D-RI86 119 MNGEMENT OF BOTTOM SEDIMENTS CONTINING TOXIC1/£ SUBSTANCES: PROCEEDINGS 0.. (U) ARMY ENGINEER WATERWAYS EXPERIMENT STATION YICKSBURG MS ENVIR. T R PATIN UNCLASSIFIED APR 87 F/G 24/3 NI.
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US Army Corps of Engineers

Water Resources

Support Center

wg Management of Bottom Sediments

Containing Toxic Substances

Proceedings of the 11 th U.S./Japan

Experts Meeting

4-6 November 1985

Seattle, Washington

Thomas R. Patin, Editor

L C..

April 1987
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11 TITLE (include Security Classification)

Management of Bottom Sediments Containing Toxic Substances: Proceedings of the 11th

U.S.IJapan Experts Meeting

12 PERSONAL AUTHOR(S)

Thomas R. Patin, Editor

13a TYPE OF REPORT 1 3b TIME COVERED 14 DATE OF REPORT (Year, Month, Day) IS PAGE COUNT

Final report FROM ____TO ____ April 1987 29))

16 SUPPLEMENTARY NOTATION

Available from National Technical Information Service, 5285 Port Royal Road, Springfield,

VA 22161.

17 COSATI CODES 18 SUBJECT TERMS (Continue on reverse if necessary and identify by block number)

FIL GOP SUB-GROUP Dredging Sedimentation

Marine deposits Toxicology

9 ABSTRACT IContinue on reverse if necessary and identify by block number) ~'' -The 11th U.S./Japan Meeting on Management of Bottom Sediments Containing Toxic

Substances was held 4-6 November 1985 in Seattle, Washington. The meeting is held

annually through an agreement with the US Army Corps of Engineers and the Japan Ministry

of Transport to provide a forum for presentation of papers and in-depth discussions on

dredging and disposal of contaminated sediment.

,10 DISRB~JrlON A lAnABILITY OIF ABSTRACT 21 ABSTRAC* SE(uR (Ai~(A ~ J NICLASSiFlED UNL MI1FD 0 SAVE AS RPT C] DT.C IAFPS Unclassified

22a NAME OF RESPOJNSIBLE NOiVIDUAL 22b TELEDcONE~ V(Iclwe AraCoy 2 (j i

DO FORM 1473, 84 MAR 81 AP d1iC ryb ,FI7'.vaAQ1, As i (A' ,4 U0 0 All other edi it p omo lar i/e (n o si

%r Pe
PREFACE ".

The 11th U.S./Japan Experts Meeting on Management of Bottom Sediments

Containing Toxic Substances was held 4-6 November 1985 in Seattle, Washington. S

The meeting is held annually through an agreement with the U.S. Army Corps of %-,% -F %

Engineers and the Japan Ministry of Transport to provide a forum for presentation of papers and in-depth discussions on dredging and disposal of contaminated sediment.

COL George R. Kleb, Commander and Director of the Water Resources Support B

Center, was the U.S. Chairman. Mr. Kenichi Fujimori, Ministry of Transport,

Tokyo, Japan, was the Japanese Chairman.

Coordinator of the organizational activities and editor of this report W, b

was Mr. Thomas R. Patin, program assistant, Dredging Operations Technical Support Program (DOTS), U.S. Army Engineer Waterways Experiment Station (WES), -

Vicksburg, Miss. Ms. Jamie W. Leach and Ms. Betty W. Watson, WES Information

Products Division, were instrumental in editing, coordinating, and preparing . .• .. -

the text. Dr. Robert M. Engler is the Manager of the DOTS Program.

-' ..- ". •- "

• +

. ,,, .. .

% - - -

A * -o + m ,

-O S

*.'~ • .

• ai'
CONTENTS

* Page

PREFACE ............. ................................ .. i

DELEGATES ................ ............................... iv

AGENDA ................. ................................ vi

JOINT COMMUNIQUE ........... ........................... . viii

STUDY ON IMPROVEMENT OF THE MARINE ENVIRONMENT

by K. Fujimori . . . . . . . . . . . . . . . . . . . . . . . . . . .. 

LAKE RESTORATION METHODS: SOME WORK, SOME DON'T

by S. A. Peterson .......... .......................... . 15

SEDIMENTATION AND EFFLUENT CONCENTRATION OF SOFT CLAY ON RECLAMATION

WORKS by Y. Watari, N. Aritomi, and N. Morii ............ 26

COMMENCEMENT BAY - A REMEDIAL INVESTIGATION OF CONTAMINATED SEDIMENTS IN

A MARINE ENVIRONMENT by J. D. Krull, T. C. Ginn, and

R. C. Barrick ........... ............................ . 48

CONTAMINANT MOBILITY AND ENGINEERING DESIGN AT A NEARSHORE CONFINED

DISPOSAL SITE--PORT OF SEATTLE TERMINAL 91 SHORT FILL

by D. A. Hotchkiss and W. W. Watson ..... ................. .. 65

TEST RESULTS OF SEDIMENT REMOVAL IN ISE BAY

by T. Nakano, M. Natori, and Y. Taguchi .... ............... .. 85

EVALUATION OF DREDGING AS A REMEDIAL TECHNOLOGY FOR THE COMMENCEMENT BAY

SUPERFUND SITE'by K. E. Phillips and J. F. Malek .. ........... ... 103

EFFECTS OF SEDIMENT REMOVAL IN TOKYO BAY

by T. Sato, S. Kojima, and H. Mori ..... ................. .. 136

DEVELOPMENT OF LEACHATE TESTING PROTOCOLS FOR DISPOSAL OF CONTAMINATED

SEDIMENTS by T. E. Myers, J. M. Brannon, and D. M. Griffin, Jr . . . . 149

- METHOD FOR ESTIMATION OF METHYLMERCURY DISSOLVED INTO WATER FROM

DREDGED MATERIAL BY USING THE MARINE COPEPODACARTIA CLAUSI

by R. Hirota, M. Fujiki, S. Tajima, and J. Asada .. ........... ... 158

WATER QUALITY MANIPULATIONS IN A EUTROPHIC IMPOUNDMENT

by J. W. Barko, A. R. Klemer, D. G. McFarland, and R. L. Chen . . . . 164

THE EFFECTS OF SEDIMENT ON THE SURVIVAL OF MYSIDS EXPOSED TO ORGANOTINS

by M. H. Salazar and S. M. Salazar ....... .................. .. 176

FOOD CHAIN STUDIES AT TIMES BEACH CONFINED DREDGED MATERIAL DISPOSAL

SITE'BUFFALO, NEW YORK by R. P. Leonard ..... ............... .. 193

i

°9
Page

THE INDIANA HARBOR EXPERIENCE

by J. A. Miller ............ ........................... 213

THE MOVEMENT OF SEDIMENT UNDER A PROGRESSIVE WAVE p _

by M. Gomyoh, E. Yauchi, and H. Kojima ......... .. . ..... 220

THE LONDON DUMPING CONVENTION AND ITS ROLE IN REGULATING DREDGED -

MATERIAL: AN UPDATE by R. M. Engler ...... ................. 233

ANALYTICAL SURVEY OF ACCUMULATIONS OF SEDIMENTS IN CANALS OF TOKYO PORT .

by S. Kimura, T. Naganuma, and S. Wano ...... ................ 245

TE ';NIQUES FOR MONITORING STABILITY OF OFFSHORE SUBMERGED DISPOSAL .'.".4.'

_NDS by E. B. Hands .......... ........................ 262

USE OF ANTI-TURBIDITY CURTAINS AT A SAND COMPACTION PILING AREA IN

YOKOHAMA HARBOUR by R. Hatano, and Y. Abe ..... .............. 264

%W-:.*-,;

., ."~ .4

*.-. .. .,4

a-:-:. ."

, . '. -

i 4 '2> .':

. -.
DELEGATES

llth U.S./JAPAN EXPERTS MEETING ON MANAGEMENT

OF BOTTOM SEDIMENTS CONTAINING

TOXIC SUBSTANCES

Japanese Delegation

Kenichi Fujimori Director, Environmental Protection Division,

Co-chairman Ports and Harbours Bureau, Ministry of

Transport

Motoo Fujiki Institute of Community Medicine, University of

Tsukuba

Shinzo Kimura Bureau of Port and Harbour, Tokyo Metropolitan

Government

Hiroshi Kojima Japan Dredging and Reclamation Engineering

Association

Nobumasa Morii Japan Bottom Sediments Management Association

Shinichi Kojima Japan Bottom Sediments Management Association

Hiroaki Mori Japan Bottom Sediments Management Association

Makoto Natori Executive Director, Japan Bottom Sediments

Management Association

Yasuo Abe Japan Bottom Sediments Management Association

Yutaka Tagunchi Japan Bottom Sediments Management Association

Naoshi Ishimatsu Japan Work Vessel Association

US Delegation

COL George R. Kleb Commander/Director, Water Resources Support

Co-chairman Center, US Army Corps of Engineers

Spencer A. Peterson Chief, Hazardous Waste and Water Branch, US

Environmental Protection Agency

J. D. Krull Project Manager, Washington State Department

of Ecology

D . A. Hotchkiss Port of Seattle Krr

K.E. Phillips US Army Corps of Engineers, Seattle District

Bob Parker US Army Corps of Engineers, Seattle District

iv

...o f.-~ - . -. - - . ~~ .. . . . . . .
*Tommy E. Myers US Army Engineer Waterways Experiment Station

*John W. Barko US Army Engineer Waterways Experiment Station

M. H. Salazar Environmental Sciences Division, Naval Ocean

Systems Center

Richard P. Leonard US Army Corps of Engineers, Buffalo District

Jan A. Miller US Army Corps of Engineers, Chicago District

RoetM nlr SAm niee aewy xprmn tto

Robert M. Eanle US Army Engineer Waterways Experiment Station

Edwad B. Hatn US Army Engineer Waterways Experiment Station

David Mathis Water Resources Support Center, US Army Corps

of Engineers

Bill Murden Water Resources Support Center, US Army Corps

of Engineers

Art Hurme Water Resources Support Center, US Army Corps

of Engineers

vp

% % %.

IL --
AGENDA

l1th U.S./JAPAN EXPERTS MEETING ON MANAGEMENT

OF BOTTOM SEDIMENTS CONTAINING

TOXIC SUBSTANCES

Seattle, Washington

4-6 November 1985

Co-Chairmen

Mr. Kenichi Fujimori

Director, Environmental Protection Division

Ports and Harbours Bureau, Ministry of Transport

Colonel George R. Kleb

Commander/Director, Water Resources Support Center

U.S. Army Corps of Engineers

Monday, November 4, 1985

0830-0930 Registration

0930-1000 Opening Remarks

1000-1030 Mr. Kenichi Fujimori, "Study on Improvement of the Marine

Environment"

1030-1100 Break

1100-1130 Dr. Spencer A. Peterson, "Lake Restoration Methods: Some Work,

Some Don't"

1130-1200 Mr. Nobumasa Morii, "Sedimentation and Effluent Concentration of

Soft Clay on Reclamation Works"

1200-1330 Luncheon (Ticket Required)

1330-1400 Mr. James D. Krull, "Commencement Bay - A Remedial Investigation

of Contaminated Sediments in a Marine Environment"

1400-1430 Mr. Douglas A. Hotchkiss, "Contaminant Mobility and Engineering

Design at a Nearshore Confined Disposal Site--Port of Seattle

Terminal 91 Short Fill"

1430-1500 Mr. Makoto Natori, "Test Results of Sediment Removal in Ise Bay"

1500-1530 Break

1530-1600 Mr. Keith Phillips, "Evaluation of Dredging as a Remedial

Technology for the Commencement Bay Superfund Site"

1600-1630 Mr. Shinichi Kojima, "Effects of Sediment Removal in Tokyo Bay"

vi

JQ.z
.,

1800- U.S. Reception (Madison Hotel - Ticket Required) p,,

Tuesday, November 5, 1985

0830-0900 Mr. Tommy E. Myers, "Development of Leachate Testing Protocols

for Disposal of Contaminated Sediments"

0900-0930 Dr. Motoo Fujiki, "Method for Estimation of Methylmercury

Dissolved into Water from Dredged Material by Using Marine

Copepod, Acartia clausi"

0930-1000 Dr. John W. Barko, "Water Quality Manipulations in a Eutrophic

impoundment"-

1000-1030 Break

1030-1100 Dr. Michael H. Salazar, "The Effects of Sediment on the Survival

of Mysids Exposed to Organotins"

1100-1130 Mr. Richard P. Leonard, "Food Chain Studies at Times Beach

Confined Dredged Material Disposal Site, Buffalo, New York"

1130-1200 Mr. Jan Miller, "The Indiana Harbor Experience" - U

1200- Travel to Port of Seattle Vessel

1300-1500 Port of Seattle Harbor Technical Tour and Luncheon

(By Invitation - Ticket Required)

1830 Japan Reception (Westin Hotel)

(By Invitation - Ticket Required)

Wednesday, November 6, 1985

0830-0930 Mr. Yasuo Abe, "Use of Anti-Turbidity Curtains at a Sand

Compaction Piling Area in Yokohama Harbour"

0900-0930 Mr. Michio Gomyoh, "The Movement of Sediment Under a Progressive

Wave"

0930-1000 Dr. Robert M. Engler, "The London Dumping Convention and Its Role

in Regulatory Dredged Material: An Update"

1000-1030 Break

1030-1100 Mr. Shinzo Kimura, "Analytical Survey of Accumulations cf

Sediments in Canals of Tokyo Port"

1100-1130 Mr. Edward B. Hands, "Techniques for Monitoring Stability of

Offshore Submerged Disposal Mounds"

1130-1200 Closing Remarks, Signing of Joint Communique

vii V .-. i. i

Wf.Z ..,
JOINT (:OK1UNIOI'E

The eleventh meeting of experts on bottom sediments containing toxic

substances pursuant to the Agreement Between the Government of the United

States of America and the Government of Japan on Cooperation in the Field of

Environmental Protection was co-chaired by Colonel (;eorge R. Kleh, Commander

and Director, Water Resources Support Center, U.S. Army Corps of Engineers,

and Mr. Kenichi Fujimori, Director, Environmental Protection Division, Ports

and Harbours Bureau, Ministry of Transport, Japan. The purpose of the meetings conducted under this agreement is the exchange of information in regulatory, technical, and operational areas relevant to management of bottom sediments and exploration of areas where joint effort appears fruitful.

Experts from both countries presented technical papers on a variety of

subjects including legal and research programs to evaluate and protect the

environment. More specifically, evaluating and predicting the behavior of

nutrients, organics, and contaminants in dredged sediments and identifying and

evaluating the many alternatives to dredging and disposal of contaminated

sediments from: lakes, rivers, waterways, estuaries, and marine waters

associated with these sediments. Management practices with the most promising

long-term utility were emphasied.

This eleventh meeting was highly successful and fruitful. The information exchange was very effective. The conference generally agreed that the

dredging technology and sediment management programs of both countries will

significantly benefit. The Co-Chairmen agreed that the next meeting will be

in Japan in 1986 and that that date will be decided jointly.

I

Commander/Director, Water Director, Envi onm al tection

Resources Support Center Division, Ports a *a!bours Bureau

US Army Corps of Engineers Ministry of Transport

COLONEL GEORGE R. KIFB KENICHI FUJIMORI

November 6, 1985 November 6, 1985

viii

-p%

J %
7.7.-.x.. Wril -. 9

STUW,' ON IMPROVEMENT OF TIlE MARINI F.NVIRONMENi

Kenichi Fujimori

Director, Environmental Protection Division

Ports and Harbours Bureau

Ministry of Transport

Kasumigaseki, Chivoda-ku, Tokyo 100

ABSTRACT

Although the marine environment in Japan has

significantly improved, problems such as eutrophication in closed bays still remain. The Ports and

Harbours Bureau of the Ministry of Transport administers improvement projects and has developed related

technologies. The success of these projects requires -.

the study of various technologies which promote the

self-cleaning functions of natural seawater and the

integration of relevant technologies into combinations

of the highest efficiency.

INTRODUCTION

The Ministry of Transport (Department of Ports and Harbours) is designated to undertake "projects for the prevention and elimination of marine

pollution." For this purpose, the Ministry of Transport has undertaken execution and investigation with regard to improving the marine environment through

direct (,,,ntrol projects (undertaken by the Ministry of Transport) and subsidized projects (undertaken by local public bodies with government subsidy).

Special investigations are made on the prevention and elimination of organic

pollution in closed bays. This paper describes future studies on improvement

of the marine environment with reference to changes in the marine environment

and results obtained in investigations already conducted.

CHANGES IN THE MARINE ENVIRONMENT

Seawater

Health and living environmental standards concerning pollution of seawater were established in 1971 based on the Basic Law for Environmental

Pollution Control. . -

Health environmental standards apply to items such as cadmium, cyanide,

Organic phosphorus, lead, hexavalent chromium, arsenic, alkvl mercury, polyclihbrinated t iphenvs (PCB) , and total mercury, which are harmful to human

hellth. !iving environmental standards apply to organic pollution sources

whiici tre hazardou5 to usable water, and are measured in units pH, such as

di olved o:{ygen (DO), biochemical oxygen demand (BOD) or chemical oxygen

.. n "l W(Io ", ded sol.-ids (SS), ":uspe" and a number o co"i fom- " groups.
J4' F'P1V LI

As a regulating measure to fulfill environmental standards, the effluent

% regulations based on the Water Pollution Control Law were enforced the same

% year. Since then, considerable improvement has been recognized in health

environments. Improvement of the living environment, however, has not been as

successful, especially in enclosed bays such as Tokyo Bay, Ise Bay, and Seto

Inland Sea (Figure 1).

me The locations of Tokyo Bay, Ise Bay, and Seto Inland Sea are shown in

Figure 2 and pertinent data given in Table 1. The seawater of these enclosed

bays is still, and the waters are not exchanged as well as in the open sea.

The bays are utilized for shipping and are surrounded by densely populated

* urban area. Therefore, the use of these waters is very dense and, at the same

time, chronic organic pollution is created by the inflow of large amounts of

industrial and household wastewater.

Under these circumstances, the reduction of the total quantity of the

pollution loads of Tokyo Bay, Ise Bay, and Seto Inland Sea has proceeded since

1979. Due to the urgent need for environmental preservation in Seto Inland

Sea, the Temporary Control Law for Preservation of Seto Inland Sea Environment

was enacted in 1973, and was revised to a Special Control Law in 1978.

Organic pollution of these areas is caused by direct inflows of pollutants and P

100

.990

9082 81

80 Total sea area 8

Seto Inlandk

70 sea

Tokyo Bay61 1

60

U50IsBa r

40 41

30

20 Number of water areas where environAchievement rate = mental standards were achiee 100 (Z) Number of water areas where environ10 mental standards were applied

0 1974 75 76 77 78 79 80 81 82

(Year)

Figure 1. Changes in environmental standards%

achievements in wide, closed water

areas (COD). Values from a survey

by Environmental Agency.

2

% .. . . .
TokyoBa

*Sea

'F0

Figure 2. Location of Tokyo Bay, Ise Bay,

and Seto Inland Sea

by organic matter generation (secondary pollution) such as phytoplankton propagation caused by increased nitrogen and phosphorus (eutrophication). In recent years eutrophication control of enclosed bays has been vigorously

investigated.

Preservation of the sea environment in the enclosed bays is intended to

protect fishing areas, prevent and eliminate red tides, and preserve

recreation areas. These situations are discussed below.

TABLE 1. TOKYO BAY, ISE BAY, AND SETO ISLAND SEA DATA

Tokyo Bay Ise Bay Seto Tsland Sea

Area, km2 1,200 1,700 21,800

Volume, km3 18 34 816

Average depth, m 15 20 37

3 ,

%,
Regarding protection of fishing areas, excessively eutrophic waters are

unsuitable for the growth of marine animals. Marine resource exhaustion is

thought to be caused by deteriorated water quality such as generation of poor

oxygen water mass from excessive oxygen consumption in water through increased

CO), and the decrease of benthos is thought to be caused by increased organic

pollution and bottom sludge.

In the relationship between water quality and marine organisms, it should

be noted that the optimum water quality differs depending on the species of

fishes, and that objectives of fisheries vary according to the change in

tastes. But, fundamentally, water quality preservation is a prerequisite for

the preservation of fishing areas, and environmental control is now required

for effective utilization of fishing areas.

Regarding the prevention and elimination of red tides, the causes of red

tides were specified after much investigation. Increased nitrogen and

phosphorus (eutrophication) is today regarded as the major cause. A red tile

is a sudden development of phytoplankton on a mass scale. The number of red

tide occurrences in Seto Inland Sea is shown in Figure 3. The frequency has

decreased since 1976, the peak year, but still remains at a comparatively high

level. Water quality has not sufficiently improved from the viewpoint of

prevention and elimination of red tides. Red tides force people in the fishing industry to limit the quantity of fish cultures and to evacuate fish

cultures (to limit or evacuate cultured fish to avoid the damage by red tides)

which involves extra costs (which are not included in the damages shown in

igure 3). Types of damage by red tides are death of potential fish catch,

escape of fishery resources from the sea areas, development of poisonous

shellfi-h (poisonous matter accumulation in shellfish bodies), death of bottom

organisms due to low oxygen levels, and adverse effects to recreation

facilities (closing of bathing resorts).

ke4 ,arding the preservation of recreational areas, clean sea water is a

prime requisite. Bathing resort water quality standards established by the

Fnvirnrnment Agencv are set under . ppm of ) ). The future demands for recreation in :a areas wi 1 l show a stead" increa-e., Ind to accommodate that inCrea.;e, it ic de-irable to create conlrtible .c,i ctnvironment- where people -

can en ov varimu'- mirire re rc,titiorn . - ,. I urvt-' determie ! that the P

(evl t bathing rts,,rt 1, t it ie i , , l.t,,, that s w,iter qual it% e

]in'it :,,nd it ion,, or , i inta jn, I;,t , ' r -

4 ,ottr, siiI' --

" 1I: v i r t .. r , , • w p o in t r:

wI r qt I;, . hIt .. T ,,ed, because ,

its !, b e . ',, , .' . ,. , ,. , . ',chinge and

- wit! the , i . . :, ,.,,'cs, the

S* ' ,, , . , 11 (ignition -.

, . .,, iles of each index in %%

% , .i,.. Standards for sludg-.

% T.., and rivers irv a.i, ,' .... .: ).8 - 1 . . ... ," , 4

. ' I, inT J apa n ' I

.4o.

4.e
(Numbe rs) H 400

4Total number of red tides

Damaging red tides 326

300 298 300

236

210 216 218 213

200

164 165

136

100 79

67 61 d 3

jj -8 2

2n18 17 277 ,. 17 8 8 ~ 1

1968 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83

(Year)

Figure 3. Total number of red tides and number of damaging red

tides in Seto Inland Sea (survey by Fishery Control

Office of Seto Inland Sea, Fisheries Agency).

700 million m 3 of sludge with over 30 mg/g COD in Tokyo Bay and others. Moreover, changes in bottom substances with the passage of time show no improvement. Table 2 shows the quantity of polluted bottom sediment in five bay

areas.

TABLE 2. PRESENT QUANTITY OF POLLUTED BOTTOM SEDIMENT IN

FIVE BAY AREAS (Over 30 mg/g COD)

Tokyo Osaka Hiroshima Suo-Nada

Sediment Bay Bay Bay Sea Ise Bay

Total Area, km2 1,200 1,529 946 3,100 510

Polluted Bottom Sediment

Area, km2 441 670 530 16.4 112

Thickness, cm 53 34 42 5 20

Quantity, million m3 235 226 221 0.8 22

NOTE: Osaka Bay, Hiroshima Bay, and Suo-Nada Sea are in Seto Inland Sea.

...

N' . ~ % .a.. % a.a-'. 'X 5 t
A.J.

_a

CIRCULATION IN THE SEA s

As previously stated, the present condition of the enclosed bays is

not satisfactory, and various efforts are under way to improve the sea

environment. Tife Ministry of Transport is also conducting bottom sediment S.

clarification projects as one sea environment cleaning measure. In such measures it is necessary to understand the balance of substances and the mechanism of seawater pollution. A model of the circulation mechanism in the sea

is discussed in the following paragraphs.

Figure 4 shows a conceptional diagram of circulation patterns. Fundamentally, seawater pollution is caused by dilution and mixing by dispersion of

inflow pollutants. This model, however, includes a eutrophication process

which is a production of organic matters (COD) from inorganic phosphorus by

phytoplankton. Phytoplankton production requires light. The model has double

layers in a vertical direction in the seawater, one with light and the other

without. Seawater pollutants exchange with the bottom substances by sedimentation and by redissolution of bottom substances back into the seawater.

The factors of each process in the model (production, decomposition,

sedimentation, dissolution, oxygen consumption) were obtained from in situ

experiments and laboratory experiments and represent the present state of pollution by adding an inflow load. In the pollution mechanism, a significant

phytoplankton production effect is calculated and shows water pollution by

eutrophication. Biological activities other than phytoplankton production and

organic matter decomposition by bacteria (such as predation by higher animals), are excluded from this model.

Table 3 shows the balance of organic pollution substances of seawater

obtained from the above model. These results reveal that internal production

(COD production by the production activity of phytoplankton from nutritive

Re-expoetton

to air Inflow inflow

load Load

OOD calcuilation oclclto

light).t F,

DQ Stt L by dProductionn

S DOn consumption

I-P DO by decopOStton

F u ia 4. Cnce t Dispersion by

flow.ingN

a- U 7 0U -. Dispersion by

Deomposition C0O I-P DO 00OnSXO~PtiOn

by deoMIPOSitIOn

COS

0p 0

U? .

(Bottis sludge)

Figure 4. Conceptional diagram of water circulation

6
.40 4o' *~~

- 12

444~~ 4 ' N '0 ~ 0~ C4 mC4%

04J.

*0 -1 10 co

0 Co M 14

0 4-

V m C3 mi(

0J 0 '1

4 0 Go2 a,4 - C4~ i

04 04.

Z 0 - 0 0 0 0% . 0 

.4, a 0% -4 a Ncc

-4 14 V - 0% 4, -4 .1
salt) has a very large COD load ratio in the sea, and that the dissolving load

from the bottom sludge has a considerable ratio in the load of nutritive salt,

which is a major cause of internal production. Therefore, bottom sludge plays

a significant role in organic seawater pollution.

SELF-CLEANIN(; ACTION OF THE SEA AND ITS ENHANCEMENT ,

As the previously mentioned circulation mechanism indicates (Figure 4),

nature is provided with a mechanism to clean inflow pollution load by dilution

and mixing, sedimentation, or decomposition. Therefore, if the inflow pollution load is under the permissible level, the environment can be maintained by

the sea's own self-cleaning action. Consequently, the concept of "environmental capacity" is proposed as maximum pollution load at permissible limits in a

definite area (e.g. enclosed bays).

Thus, nature's self-cleaning action can be taken into consideration when

environmental cleaning measures are aL nted. Specifically, the self-cleaning

action such as dilution and mixing in the above-mentioned substance circulation mechanism can be promoted, or actions which have been excluded (e.g. predation by higher animals) can be promoted. Development and research in this

field are under way at various organizations. In the field of wastewater

treatment, soil infiltration systems of small-scale wastewater treatment (by

the adsorption, filtration, and decomposition actions of soil) and the stabilizing process of nitrogen and phosphorus with water plants (waterhvacinth,

etc.) are especially being developed.

The Ministry of Transport has studied methods to promote the sea's own

seif-cleaning action.

The main factors of the sea's self-cleaning actions are exchange of sea- water, exposure to air, predation, and the seawater cleaning action of dry

. beaches and sand beaches. These factors are discussed below.

Seawater exchange to prevent standing water in enclosed bays can be promoted by widening and deepening the mouths of the bays, forced water convev- ance with electric power, excavation of new waterways, and construction of

trenches (excavation of trenches in the sea bottom). Seawater exchange

' promotion processes for wide bays such as Tokyo Bav, Ise Bay, and Seto Inland

Sea are now being researched with model tests, and value simulations are under

way. It can be expected that seawater exchange can be promoted as an additional effect Irom excavation of new fairways at bay mouths. On the other

hand, in small areas such as inside harbor breakwaters, a process to promote

seawater exchange has been achieved in harbor improvement projects. In these

cases, one measure is to construct a raceway in one part of a breakwater which

will promote interchange with water from the open ocean. Figure 5 shows a

raceway in the Kikuma Harbor breakwater, Ehime l'refecture, constructed in

1984.

Exposure to air is a process which >upplies oxvgen to seawater. This 

exposure promotes organic pollutant (COlD) decomposition, one of the substance

circulation mechanisms (Figure 4). This process adopts a method by which air

bubbles are blown into the seawater bv using electric power; therefore pollutant dilution by mixing with seawater is expected to result ai; an additi ona I

effect. In this respect, the Ministrv of TranMport carried out veri ication

S".

..-.

. -. . -
C- WY'~. W-T. . XWWWWj ~ jP J U.." kr WUP .F J* SI. PW Pi ~ ~-... PWVV~ .. ..

-#5

6.00

Cwo 1. 50 1. 20

of the facility 3. ,0

0.20

-5.70 +4.50

-3.40 "

4.0Om x 4. 4m x S. 4m

W = t173. 63 /un t 7

2.505'V

1 .10

Covered i'

ripraps Covered

-0.20 20e0. 4 40o

2.30 1.2 .8 4.40 Lo - .20 0.50

8.40.

Figure 5. Kikuma Harbor raceway project

tests at Shimizu Harbor in 1982, the outline of which is shown in Figure 6.

The result of the tests revealed that, in a definite sea area, exposure to air -.

shows layer breakdown and air dissolution effects. .5'.,

The increase of DO and the decrease of phosphorus were especially significant. Though this system requires maintenance, spectacular effects can be

expected by using the system as an ornamental fountain. It is desirable to

utilize the system in a tutal waterside environment improvement project.

Regarding predation by higher animals, the activities of seaweeds, fish,

and shellfish to take in pollutants were observed in nature, and a concept to ,. *"

preserve the environment by controlling these activities was realized. Utilization of living creatures and plants presents certain problems such as the

scale of effect, compared with total pollution load, and the maintenance of

living conditions for the creatures and plants. It is, however, possible to

use this method as a very reasonable environmental cleaning method by utilizing recovered living creatures and plants as resources. It was determined %4

from laboratory tests that the maximum intake speed was 20 Ltg COD/piece/minute

with filter feeders (shellfish). Nitrogen and phosphorus stabilization using

large seaweeds has been studied hv the Fisheries Agency, and the Ministry of

9

tf o E

"5.'o
F11

f

Buoyw

iii I IWire

T I o I I I I I I I I I I I I I I I i i p e s l t b

Buried block%

Figure 6. Test of exposition to air at Shimizu Harbor

*Transport is conducting verification tests related to the use of a living fil-

*ter of reeds to treat excess organic sludge water at Ube Harbor, 1982-1984.

Figure 7 is a plan view of the site.

The main factors of the seawater cleaning action of dry beaches and sand

beaches are filter feeder predation, exposure to air by wave breakdown which

accelerates the decomposing action of bacteria in aerobic environments, and

absorption of pollutants by sand particles. It is calculated that these provide significantly high cleaning functions. Therefore, the preservation and

preparation of dry beaches and sand beaches are very effective sea environment

preservation measures together with utilization as recreation places. Further

studies are expected.

FUTURE SEA CLEANING MEASURES

As stated, there are various proc.-sses to promote self-cleaning actions

of the sea. In adoption of cleaning methods for wide enclosed bays such as

Tokyo Bay, Ise Bay, and Seto Inland Sea, these processes can be combined or

arranged, but many problems still remain, for example, determining, the best

arrangements for raceways, choice of air exposure equipment, construction of

dry and sand beaches, adjusting living conditions for higher animals to maintain their predation activities, and arranging equipment for nitrogen and

phosphorus stabilization by seaweeds.

However since 1979 the Ministry of Transport has carried out feasibility

studies related to bottom sediment clarification (removal of organic sludge

* from the sea bottom) as part of a study concerning seawater cleaning measures

in enclosed bays. The investigations were carried out on actual pollution

situations; the scope of the research was broad and included simulation of
' g rowth ,- ~~condition .

valve

~a~* ecerArea where reeds grow

,low Weds or

(I West side

treatment East sidear s

plant %-Y treatnentWte

SplantC)po

WaterS~g poolexi j 1u~wte Excess

Water wate

Figure 7. Sludge water treatment facility at Ube Harbor

(a living filter)

seawater pollution and test engineering works. Dissolution of nutritive salts

from the surface layer of the sea bottom, biological production in the sea,

and other important data were obtained.

The effects of various bottom sediment clarification processes were confirmed through tests and follow-up studies in the sea areas. Dredging, sand

covering, and trench digging were tested, and the results of follow-up studies

were reported. Some are as discussed below.

Sand covering work was carried out in Hiroshima Bay in Seto Inland Sea.

In November 1979, sand covering (1.92 ha) was done to a 50-cm thickness, and

sand covering (4.48 ha) to a 30-cm thickness was done in August 1980.

Figure 8 shows the results of follow-up studies of dissolution controlling effects. It was determined that pollutant dissolution (COD, T-P, and

T-N) from the sea bottom was decreased by covering the bottom sludge with

sand, and that the effects of the covering lasted. Dissolution of T-P was

remarkably decreased by sand covering. It is assumed that the chemical adsorption of phosphorus by sand particles in the aerobic environment at the sea

bottom in addition to physical restriction by covering served to decrease

pollution in the bay.

%i
.44

0 50 Sand Covering IF

100 6 30 cm Sand Covering I P---"k\

5 Other areas I I I

50 l

., 7 . , _ , " "o

-'00 ' " % 

a. COD.-.

10

. 6

44

a. IOD

100-

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g I I • I , / ' I

I ' / I __, /-; S.'-::.

b. T -I." .

250 "."/

-50

Oc.be.Fb . T-. Pb u .Io . Fe.Aq o .Ft-4u, 

2s0 44

200 ,

ct ro1 on 1r shfmt.. 

-50-

%..

con ro /i -ioBa "

"".- / 4 

0i'2*"--p"4

- *54%'44t
Dredging and sand covering were carried out in Ise Bay. In June 1980, V

dredging 60 cm in depth (1 ha), and in June 1981 dredging (I ha) of 30 cm in

depth was conducted. In June 1983, sand covering (5 m by 5 m each) was

applied to a 10-cm and 30-cm thickness. Figure 9 shows the results of followup studies of benthic organism recovery. The average number of benthic organism species and the actual organism population increased. The increase of

benthic organisms in cases of sand covering was especially remarkable.

Improvements in the sea environment are expected to result from bottom

sediment clarification work such as dredging and sand covering. Further investigations and research will be continued to undertake bottom sediment clarification projects. It should be noted that, as stated, the selection of

suitable cleaning methods should be made carefully because the sea's substance

circulation is extremely complicated.

Therefore, overall sea environment cleaning measures will be established

by combining bottom sediment clarification works and various self-cleaning

promoting methods. Details of the processes will be established in the

future. It is important to review closely the most suitable process combinations to preserve the environment of enclosed bays.

CONCLUSIONS

Tokyo Bay, Ise Bay, and Seto Inland Sea will become more important as

valuable spaces and their resources will become more important with the progress of the development of the sea. Under these circumstances, the Ministry

of Transport will continue in its efforts to establish total cleaning measures

for the environment of the sea around Japan. Adequate cleaning projects will

be carried out in accordance with changes in seawater quality and bottom substances, and with the demands of the time.

A.•

13

P w % %
1

40

1 0 0 6 10. o 2 4 6 8 10 12 2 4 6 13 i0 12 2 4 6 9 10 12 2 4 10 12 - 20

* ...

-a Iooo

m °. ~ ~0-----0 60 cm Oredginq/l %

.. 1800 .

--k 30 an Dredging

Othe areas

0---D, 10 on Sand Covering

150

" --- g 30 ow Sand Covering. ," ~~~1400ii It a

1300

1200

2900

2800

2700 b 0c r~lgT

2600 Otrars

,"00 Ix

0 6 a t0 12 2 4 6 a t0 12 2 4 h 8 to 12 , 4 6 8! 10 1,2 4 6 8 l 03 12 2 4 " %

"i 'l F 1B ' '64 MI.,

,i q

_ Figure 9. Recovery, of benthic organisms after

dredging and sand covering, se Bay-

*° '1

-" 14 % 2300

°° 'em

2200 -I,]
LAKE RESTORATION METHODS: SOME WORK, SOME DON'T

Spencer A. Peterson

Chief, Hazardous Waste and Water Branch

US Environmental Protection Agency

Corvallis Environmental Research Laboratory

200 S.W. 35th Street

Corvallis, Oregon 97333 %

ABSTRACT

Lake restoration has grown out of pilot and fullscale lake manipulation studies of the late 1960s and

early 1970s. Some procedures have proven to be successful, and some have failed. This paper broadly

divides the techniques into those that have proven to

be successful, those that require more research, and

combinations of treatments that are desirable together

and those that should be avoided together. The procedures are divided further into those that reduce

nutrient concentrations, and those that control algae

and macrophyte biomasses directly. Both successes and

failures are addressed with assessment of the reasons

for either response. The procedures are summarized

with assessment of the reaons for either response.

The procedures are summarized briefly from the major

reference on this topic: Lake and Reservoi4"

Restoration (1986) by G. D. Cooke, E. B. h, S. A.

Peterson, and P. R. Newroth, Butterworth Press.

Boston, Massachusetts.

INTRODUCTION

Cultural eutrophication of lakes was thought for many years to be an

irreversible process. Even those lakes which had wastewater discharges

diverted from them showed little if any signs of recovery. This latter fact

attests to the very slow process of lake recovery if the lakes are left to.o"

their own devices. However, a blooming of research in the late 1960s and

early 1970s began to reveal some aspects of the trophic dynamics of lakes - -

previously not understood. For example, in 1966, Sakamoto published his now

famous paper depicting the relationship between total phosphorus concentrations in the water and algal biomass. Vollenweider (1975) began to publish

papers in 1975 describing the relationships between phosphorus loading rates

to lakes and their hydraulic residence times. The phosphorus discharge rates

and internal loss rates were gradually refined throughout the early 1970s,

thus producing the basis for lake restoration design criteria. The object o(-

lake restoration became either phosphorus reduction in the water column or

direct control of algae or macrophyte biomass. Kany methods were developed to

accomplish these goals. Some of the methods have proved successful and srme

15'

~. - %-|
have not. The purpose of this paper is to provide a brief summary on the

success and failure of several different lake restoration procedures. The

information in this paper is from a forthcoming book by Cooke et al. (1986).

SUCCESSFUL TECHNIQUES

Procedures to Reduce

Nutrient Concentrations

Nutrient Diversion

Diversion of nutrient income is widely recognized as a highly necessary

and usually essential first step to obtaining improvement in lake trophic

state. Uttormark and Hutchins (1980) examined the responses of 23 lakes to

diversion and found that while concentration of nutrients (P in this case) may

have declined, only 30 percent of the lakes showed improvement to a lower

trophic state. This may have been because diversion was insufficient to lower

concentration to the level that would change the lakes from eutrophic to mesotrophic. Despite this problem, a reasonable reduction in algal biomass, absence of blue-green algal scums, and a reduction of fecal coliform counts to

an acceptable range will make diversion a success. '.

Another reason diversion might fail to significantly improve trophic

state is continued release of nutrients from sediments into the water column.

This factor, along with morphometric and hydrologic features such as mean

depth and flushing rate, is important in determining how much change in concentration will occur after diversion and how long it will take for the lake

to reach a new, lower concentration equilibrium. Ultimately, internal P release should decline as older, richer sediments are depleted of nutrients and

are covered with those of lower nutrient content, thus producing lower nutri- P

ent levels in the water column.

Silt income control may be very significant in preventing the rapid

development of shallow water and the spread of nuisance matrophytes An

extensive littoral area from long-term deposition might require sediwent

removal or other procedures before macrophyte growth is controlled. Control

of sediment income from the watershed is thus again an essential first step to

improvement in trophic state.

Dilution/Flushing

Dilution reduces the concentration of nutrients in the water column by

adding nutrient-poor water. Flushing reduces algal biomass by increasing the

loss rate of cells. Both effects will occur if large amounts of low nutrient

water are added.

Dilution has been very effective in Moses Lake and Green Lake, Washington

(Oglesby 1969). Welch (1981) concluded that the best plan is to have a continuous low-rate input of low-nutrient water, coupled with nutrient diversion. %

While this procedure will bring about lake improvement, its applicability is

limited by availability of nutrient-poor waters for diversion into eutrophic

lakes.

16

0 . . % *. .- *~ ~. * % % % r. %~ d 
Phosphorus Inactivation/Precipitation

The purpose of this technique is to lower the concentration of P in the

water column by either precipitating it or preventing its release from sediments (inactivation). Phosphorus in the water column is sorbed to salts of

aluminum (aluminum sulfate or sodium aluminate) as they are added to the lake

surface or to the hypolimnion. With inactivation, sufficient aluminum is

added to create a barrier to P release at the sediment/water interface.

Phosphorus inactivation/precipitation has the potential to create aluminum toxicity in lakes. This situation could occur through excessive application of soluble aluminum (Al III) or through a decrease In pH following application of appropriate amounts of aluminum. Kennedy and Cooke (1981, 1982)

have described a method for determining the maximum safe dose of aluminum

sulfate for a lake, based on lake water alkalinity and toxicity of dissolved

aluminum to trout. An alternative dose procedure for softwater lakes has been

described by Dominic (1980). Following these procedures ensures maximum P

inactivation while minimizing the potential for creating toxicity problems.

The P inactivation technique is particularly effective in long-term

control of P concentration in the water column (Cooke and Kennedy 1981a, %

1981b). The longest period of P control to date is 12 years (Garrison and

Knauer 1984). Failures have been due to insufficient dose, polymixis, and

insufficient nutrient diversion.

Sediment Removal

Sediment removal is one of the most commonly prescribed techniques for

long-term lake improvement. Lake deepening and the removal of toxic materials, macrophytes, and nutrient-rich sediments are its main purposes. Until

recently (Peterson 1979, 1981, 1982), little published documentation about its

effectiveness, environmental impact, and costs was available.

Lake deepening projects are generally successful except in instances

where sediment income remains high. Similarly, control of nutrient release

from sediments can be achieved by removal, although it is often less costly to

do so through P inactivation. There is little documentation of macrophyte

control by dredging. The success or failure of macrophyte control appears to

be associated with dredging beyond the light compensation depth. C-.

There is widespread concern about the negative environmental impacts of

dredging, but most negative effects (algal blooms, high turbidity) are of

short duration. One common problem is inadequate sizing of disposal area.

Diking in upland areas is the most frequently used means of containing the

dredged material since the filling of wetland areas is strictly controlled.

Fill permits are required for any areas in excess of 10 ha.

Dredging costs range from $0.25 to $14.00/m 3 . Removal of contaminated

material may exceed $25.00/m. One way of lowering costs is to sell incontaminated dredged material for topsoil dressing.

17 (C

.1~~ ~ .. ~~ . . . . . . . . ... .. .... . . . .
PEP no V M,%p r -0 MP -J. -. F~ -e -4 -W. rnpr ... e 

Procedures to Control

Algal and Macrophyte Biomass

Drawdown

'U'

Lake level drawdown is used successfully to control the growth of certain

mactophyte species, to consolidate flocculent lake sediments, to provide an

opportunity to repair docks and dams, to remove sediment or to install sediment covers, and to manage fish (Cooke 1980a).

Not all aquatic plants are susceptible to the freezing or high temperature conditions of a winter or summer drawdown. Alligatorweed (Alternanthera

philoxeroides) and brittle naiad (Najas f~exilis) have been reported to in- -V

crease in density after a drawdown. Waterlily (Nuphar sp.), waterhyacinth

(Eichhornia crassipes), and musk grass (Chara vulgaris) usually decrease. For

most macrophytes, the published data are too sparse to generalize. A danger

may be that susceptible species will be replaced by tolerant ones, leading

some investigators to suggest that the best control will be achieved by 2 to

3 years of drawdown, followed by 2 years of stable water levels (Lantz et al.

1964; Lantz 1974). Most drawdowns are done during the winter since this does

not interfere with most recreational uses and there is no invasion by terrestrial plants. Also, there is greater assurance of refill during spring melt

and rainfall.

Drawdown has been effective in fish management. In Louisiana reservoirs,

populations of shad and sunfish are removed by winter drawdown, and their A

spawning is prevented by summer drawdown (Lantz et al. 1964). In reservoirs

with 5 or more consecutive years of drawdown, game fish standing crops and

reproductive rates have increased.

Negative effects of water level drawdown include algal blooms upon

refilling. Fish kills have occurred in isolated pools of water during drawdown, and great changes have taken place in the macroinvertebrate communities.

This management technique can be effective in macrophtyte control and can be beneficial in the sense that it provides management personnel with access

to the lake for the purpose of enacting other techniques.

Sediment Covers 'a

Several sheeting materials have been tested for their effectiveness in

preventing macrophyte growth (Cooke 1980b). Impermeable materials such as

polyethylene have been found to be effective but troublesome because they

accumulate gases underneath and balloon to the surface. One way to prevent

"ballooning" is to cover the plastic with gravel and silt, but this practice

provides new substrate for plant growth, thus defeating the purpose of the

plastic cover. Burlap has been shown to be effective for one growing season,

but the material usually decomposes and must be replaced annually.

Fiberglass screen coated with polyvinyl chloride (PVC) has been very

effective in preventing macrophyte growth. It is easy to install and does not

"balloon," but is very expensive ($140 to $170/ft 2 ; $2.15/M 2 ). Perkins,

Boston, and Curren (1980) suggested that control with screening was achieved

by physical restriction of plant growth through the screen. In most'..N.

18" • .
instances, the screens must be repositioned annually to remove accumulated

silt. Due to its cost, this material appears to be best suited for small

areas around docks and bathing beaches.

TECHNIQUES REQUIRING MORE RESEARCH AND DEMONSTRATION

*Procedures to Reduce

Nutrient Concentration

Hypolimnetic Withdrawal

The object of this technique is to siphon or pump nutrient-rich hypolimnetic water from the lake. This technique removes nutrients from the lake

and should reduce the impact of vertical entrainment of nutrients on the

epilimnion. The siphon is sometimes called an "Olszewski tube" after its

originator (Olszewski 1961).

Experiences with this device in small European lakes have been described

by Bjork (1974) and Gachter (1976). Total P and internal P release decreased,

transparency increased, and fewer blue-green algae were present.

This technique deserves further study since it is simple, dependable, and

inexpensive. The high P, low dissolved oxygen content of the hypolimnion

water could pose a threat to receiving waters. Other possible problems might

include disruption of the thermocline, excessive water loss from the lake, and

the requirement that the discharge end of the siphon be below the surface

level of the lake.

Sediment Oxidation

Ripl (1976) described a procedure (discussed below) for oxidizing the top

15 to 20 cm of anaerobic lake sediment to reduce internal nutrient release.

There are few published data regarding the success of this new procedure and

its cost.

Fe(C1 3 ) is added first if Fe is naturally insufficient. Ferric hydroxide

formation binds P and the sulfur in FeS is lost as H S. Calcium hydroxide is

added next to increase pH to the optimum for denitrification. Finally, calcium nitrate is added to the sediments, oxidizing reduced carbon and acting as

an alternative electron receptor. Reduction of iron (III) does not occur

until the nitrate is exhausted. The chemicals are added using a harrow

device. A positive result (lower pH, NH4 decrease, 02 demand lowered) was

found in Lake Lillesjon, Sweden (Ripl and Lindmark 1978), but costs of chemicals and equipment were high. Further laboratory and field evaluations of

this technique are needed.

Procedures to Control

Algae and Macrophyte Biomass

Biological Controls

Biological control methods may be the most promising because they offer

the possibility of exerting control of nuisance plants without eradication and

19

.

%'- - -- - *. * - -
without the use of expensive machinery or toxic chemicals. Among the most

controversial of the proposed biological control methods is the introduction

of grass carp, or white amur (Cterzopharyngodor idelia Val.), a voracious consumer of macrophytes. Successful introductions have been reported by Mitzner

(1978) and by Shireman and Maceina (1981). The US Army Corps of Engineers and

others are conducting large-scale feasibility studies in Florida. While new

data are now being accumulated, there remains no certainty with regard to the

effects of these animals on other species, their role in nutrient recycling,

whether they transmit fish diseases, and whether or not they will reproduce

and infest nontarget waters. Currently the fish is widespread in the southern

Mississippi River system. It will be fortunate indeed if this animal proves

to be useful for plant control. Many releases were made before mans of the

above questions were addressed.

A plant pathogen (Cercoopora rodmanii) appears to be effective in control

of waterhyacinth (E'ichhornia crassipes) and is now being prepared for a largescale operations test by the US Army Engineer Waterways Experiment Station

(Freeman et al. 1981).

Since LaMarra (1975) reported the nutrient recycling ability of the com- ..

mon carp, others have further demonstrated eutrophying characteristics of benthivorous fish (Anderson et al. 1978; Keen and Gagliardi 1981). The word

"biomanipulation" has been used to include lake improvement activities in

which fish such as bullheads (Ichtalurids) are removed, or in which the pelagic food web is altered to decrease predation on the large herbivorous zooplankton (Shapiro, LaMarra, and Lynch, 1975; Shapiro 1979). These and other

procedures deserve considerable further support and attention. These methods

may, for example, be one way to improve lakes where significant nutrient

diversion cannot be achieved.

Artificial Circulation

The purpose of this procedure is to prevent thermal stratification or to

destratify the lake. The most effective and least expensive technique is to

introduce compressed air at maximum depth, increasing a curtain of bubble and

intensive mixing. An airflow rate of 9.4 m 3 /min/km2 should be adequate

(Lorenzen and Fast 1977).

Artificial circulation is included as a "technique requiring more research" because the expected results often are not realized. The reason for

this is not readily explained. However, Pastorak, Ginn, and Lorenzen (1981)

found that in only 20 percent of the cases reviewed was the flow rate of

9.4 m /min/km2 achieved, a factor that might account for some of the reported

failures of the technique. The principal improvement is increased aeration of

the water column and expanded fish habitat. Theoretically, aeration and circulation should inhibit P release from sediments, limit algal productivity by

increasing cell residence time in dark waters, decrease pH, and perhaps shift

the competitive balance from blue-green algae to greens and diatoms, limit the

survival of blue-green pseudovacuoles (buoyancy), and favor the survival of

herbivorous zooplankton. Phytoplantkon decreased in about half the cases examined by Pastorak, Lorenzen, and Ginn (1982). Transparency decreased more

often than it increased. Circulation may introduce nutrients to the water

20

%
column, and in nutrient-limited lakes an increase in biomass may occur. This

technique might be most effective in lakes where nutrients are not limiting. However, additional research is needed.

Hypolimnetic Aeration

This is a technique to aerate the hypolimnion without achieving destratification (Pastorak, Lorenzen, and Ginn 1982). It is accomplished by an "airlift" in which water is lifted up a cylinder by compressed air to the lake

surface, aerated, and then returned to the hypolimnion.

Successful oxygenation is usually achieved, although metalimnetic oxygen

minima may occur with an undersized aerator. Phosphorus concentration may be

reduced following the introduction of oxygen; however, hypolimnetic levels

tend to remain high. There are few data on biological effects, including

those on phytoplankton, zooplankton, and fish (Pastorak, Lorenzen, and Ginn

1982). More documentation about the responses of lakes to this treatment is

needed.

Harvesting

Harvesting is one of the more controversial procedures, in part because

there is little scientific evidence to demonstrate long-term effectiveness.

The technique has been incorrectly categorized with herbicides as a cosmetic

treatment. Unlike the introduction of toxic materials to lakes, nutrients and

oxygen-consuming biomass are removed during a harvest, thus protecting the lake

from acute oxygen depletion as occurs with herbicides. There is some evidence

that longer term control of macrophytes can be achieved by employing a proper

cutting frequency and cutting technique. Since harvesting is usually less

costly than herbicides, and because removal of nuisance plant biomass can have

a protective effect for the lake, the use of this procedure deserves more

careful attention and additional experimental work.

COMBINATIONS OF LAKE RESTORATION TECHNIQUES

For the most part, each lake or reservoir restoration or improvement

technique has been addressed separately, as if the use of one precludes the

simultaneous use of another. However, "integrated control methods," similar

to those used in agriculture, may be far more effective and less costly than

use of any single technique.

Some procedures, when used together, could counter each other or produce

a negative effect. Some of these situations are summarized below.

* Flushing. Do not use with hypolimnetic withdrawal because the probability of destratification is greatly enhanced and would negate the effectiveness of withdrawal if it occurred. It is not compatible with dilution

unless the water used for flushing Is very low in nutrients, th's making the

effects of the two essentially identical. If used with phosphorus inactivation or sediment oxidation, there is a r;:;k that chemicals added to the sediments might be removed. Flushing in conjunction with sediment removal would

have to he used with care since turbidity and nutrients generated by the

dredge would quickly be transported through the lake. If they are used

simultaneously, then silt curtains around the dredge site would be useful.

21P

",'--"--'--",' "'""'":" ",'"' "'""''
Flushing and lake level drawdown should not be used in the same season. The

introduction of phytophagous fish must be done only where the fish cannot

escape to downstream ecosystems.

* Phosphorus Inactivation. Flushing is not compatible with this procedure, as described earlier. Aluminum salts and the reagents used in sediment oxidation might be incompatible, especially if pH is affected and denitrification is impeded. Artificial circulation and hypolimnetic aeration

could interfere with the effectiveness of phosphorus inactivation by mixing

the treated sediments with overlying water.

Sediment Oxidation. As noted above, there could be problems with the

combined use of sediment oxidation and flushing or phosphorus inactivation.

* Biological Controls. Phytophagous fish should be introduced only where

they cannot escape downstream. Hypolimnetic withdrawal, dilution, and flushing together with fish stocking would require barriers to prevent the fish

from escaping.

Very little information has been published on the application of two or

more techniques in the same lake or reservoir. This is due in part to high

costs and also to the desire to learn about one procedure without the confounding effect of additional manipulations. The next major advances in lake

restoration technology might well be in the area of combinations of lake "'

restoration techniques.

The compatibility of some procedures is obvious. An example is lake

drawdown with sediment removal and the application of sediment covers. It is

also used in fish management, where it might result in production of larger

sport fish. Harvesting can enhance the effectiveness of 2,4-D applications by

allowing access of the chemical to root systems, and plants damaged by a harvester may be more susceptible to plant pathogens. Diversion of nutrient

loading is obviously compatible, if not necessary, with every technique.

The entire area of integrated control of nuisance aquatic vegetation is

in its infancy. Documentation of lake management via combined methods is

strongly urged. Effectiveness of the techniques as well as a cost analysis is

needed.

CONCLUSIONS

The goal here is to briefly review and analyze the current state of knowledge of the procedure to protect, improve, and restore eutrophic lakEs and %

reservoirs. An obvious finding, while not always explicitly stated, is the

small amount of actual knowledge about protection, management, and restoration

of freshwater resources. At present, solutions seem to be based almost exclusively on the application of chemicals or the introduction of machinerv. In

many cases these approaches are effective, but they are also expensive. The

developing interest in biological control may greatly add to the arsenal of -

effective and inexpensive techniques. This avenue may become extremely important in the near future as the demand for clean water increases.

%

"2 ) )

, $*
There re ample reasons to believe that surface water resources of both

developed and developing nations will continue to deteriorate with the rising

demands of agriculture and the inability of governmental units to provide

adequate sewage treatment as urban populations increase. There is a need to

greatly increase our knowledge of freshwater ecosystems and of the methods to

manage, protect, and restore them. This is vital, not only for recreational

purposes, but for consideration of human health and economic development.

Several of the above procedures rely on chemical manipulations of the '1

sediments. Far more knowledge is needed about this practice, including studies on the significance of internal loading. We have very little information

about the long-term effectiveness and impacts of these restoration and improvement methods and, finally, we know next to nothing about the efficacy of

combined uses of these procedures. An in-depth coverage of the above lake

restoration practices is contained in the book entitled Lake and Reservoir

Restoration by G. D. Cooke, E. B. Welch, S. A. Peterson, and P. R. Newroth.

It is scheduled for publication by Ann Arbor Science, Butterworth Press,

Boston, Massachusetts, in February 1986.

REFERENCES

Anderson, C., Berggen, H., Cronberg, G., and Celin, C. 1978. "Effects of

Planktivorous and Benthivorous Fish on Organisms and Water Chemistry in

Eutrophic Lakes," Hydrobiologia, Vol 59, pp 9-16.

Bijork, S. 1974. "European Lake Rehabitation Activities," Institute of

Limnology, Univ. of Lund, Lund, Sweden.

Britt, D. L., and Fraser, J. E. 1983. "Effectiveness and Uncertainties

Associated with the Chemical Neutralization of Acidified Surface Waters,"

Lake Restoration, Protection, and Management, EPA-440/5-83-001, pp 96-103.

Cooke, C. 1). 198 0a. "Lake Level Drawdown as a Macrophyte Control Technique,"

Water Res. Bull., Vol 16, pn 317-322.

C.oke, G. 1 1980b. "Covering bottom Sediments as a Lake Restoration

Technique," Water Res. Bull., Vol 1H, pp 921-926.

Cooke, G. )., and Kennedy, R. H. 1981a. "Precipitation and Inactivation of

Phosphorus as a Lake Restoration Technique," EPA-600/3-81-012.

Cooke, (;. )., and Kennedy, R. H. 1981b. "State-of-the-Art Summary of

* Phosphorus Inactivation as a lake Restoration Technique," Proceedings,

Workshojq (in Al gal Management and Control, Technical Report F-8I-8, 5.S Army

(orps of nfgi neers, l.as Vegas, Nev.

C ike, . K, We lch, F. B., Peterson, S. A., and Newroth, P. R. 1986. lake

and Res,rvoir Restoration, Ann Arbor Science, Butterworth Press, Boston, Mass. " -

(in ( pr ess

[)ominlic, 1). k. , If. 1980. "Hypolimnetic Aluminum Treatment of Soltwater

Arnab e':,;.,-i ok lake," Restoration of Lakes and Inland Waters, EPA-', 4i(/',-8-(1l]0,

23

-. - ... % *.**.,*> .".. *

.... ... ... ... ... ... ... ... ... ... ... ... .--
Freeman, T. E., Charudattan, R., Conway, K. E., Cullen, R. E., Martyn, R. D.,

McKinsey, D. E., Olexa, M. T., and Reese, D. F. 1981. "Biological Control of

Aquatic Plants with Pathogenic Fungi," Technical Report A-81-1, US Army Engineer Waterways Experiment Station, Vicksburg, Miss.

Gachter, R. 1976. "Lake Restoration by Bottom Water Siphoning," Schweiz Z.

Hydrol., Vol 38, pp 1-28.

Garrison, P. J., and Knauer, D. R. 1984. "Long Term Evaluation of Three Alum

Treated Lakes," Proceedings, North American Lake Management Society Conference, Knoxville, Tennessee, EPA-440/5-84-O01.

Keen, W. H., and Gagliardi, J. 1981. "Effect of Brown Bullheads on Release

of Phosphorus in Sediment and Water Systems," Prog. Fish Cult., Vol 43,

pp 183-185.

Kennedy, R. H., and Cooke, G. D. 1981. "Aluminum Sulfate Dose Determination

and Application Techniques," Restoration of Lakes and Inland Waters,

EPA-440/5-81-010, pp 405-411.

Kennedy, R. H., and Cooke, G. D. 1982. "Control of Lake Phosphorus with

Aluminum Sulfate. Dose Determination and Application Techniques," Water Res.

Bull., Vol 19, pp 389-395.

LaMarra, V. J., Jr. 1975. "Digestive Activities of Carp as a Major Contributor to the Nutrient Loading of Lakes," Verh. Int. Ver. Limnol., Vol 19,

pp 2461-2468.

Lantz, K. E. 1974. "Natural and Controlled Water Level Fluctuation in a

Backwater Lake and Three Louisiana Impoundments," Louisiana Wildlife and

Fisheries Comm., Baton Rouge, La.

Lantz, K. E., Davis, J. T., Hughes, J. S., and Schafer, H. E. 1964. "Water

Level Fluctuation--Its Effects on Vegetation Control and Fish Population

Management," Proc. 19th Ann. Conf. Southeast. Assoc. Game and Fish Comm.,

Vol 18, pp 483-494.

Lorenzen, M. W., and Fast, A. W. 1977. "A Guide to Aeration/Circulation

Techniques for Lake Management," EPA-600/3-77-004.

Mitzner, L. 1978. "Evaluation of Biological Control of Nuisance Aquatic

Vegetation by Grass Carp," Trans. Amer. Fish. Soc., Vol 107, pp 135-145.

Oglesby, R. T. 1969. "Effects of Controlled Nutrient Dilution on the

Eutrophication of a Lake," Eutrophication: Causes, Consequences, Correctives,

National Academy of Sciences, Washington, pp 483-493.

Olszewski, P. 1961. "Versuch elner ableitung des hypolimnischen wassers aus

etnen See, Ergebhisse des ersten Versuchsjahres," Verh. Int. Ver. Limnol.,

Vol 14, pp 855-861.

Pastorak, R. A., Ginn, T. C., and Lorenzen, M. W. 1981. "Evaluation of

Aeration/Circulation as a Lake Restoration Technique," EPA-600/3-81-014.

24

.. .. .~ -4 .-. . , . . . , . . . . . . . . . . - . i:
Pastorak, R. A., Lorenzen, M. W., and Ginn, T. C. 1982. "Environmental

Aspects of Artificial Aeration and Oxygenation of Reservoirs: A Review of

Theory, Techniques, and Experiences," Technical Report E-82-3, US Army

Engineer Waterways Experiment Station, Vicksburg, Miss.

Perkins, M. A., Boston, H. L., and Curren, E. F. 1980. "The Use of Fiberglass Screens for Control of Eurasian Watermilfoil," J. Aquatic Plant Manage.,

Vol 18, pp 13-19.

Peterson, S. A. 1979. "Dredging and Lake Restoration," Lake Restoration,

EPA-400/5-79-001, pp 105-114.

Peterson, S. A. 1981. "Sediment Removal as a Lake Restoration Technique,"

EPA-600/3-81-013.

Peterson, S. A. 1982. "Lake Restoration by Sediment Removal," Water Res.

Bull., Vol 18, pp 423-435.

Ripl, W. 1976. "Biochemical Oxidation of Polluted Lake Sediment with

Nitrate--A New Restoration Method," Ambio, Vol 5, pp 132-135. %

Ripl, W., and Lindmark, G. 1978. "Ecosystem Control of Nitrogen Metabolism

in Sediment," Vatten, Vol 2, pp 135-144.

Sakamoto, M. 1966. "Primary Production by Phytoplankton Community in Some

Japanese Lakes and Its Dependence on Lake Depth," Arch. Hydrobiol., Vol 61,

pp 1-28.

Shapiro, J. 1979. "The Need for More Biology in Lake Restoration," Lake

Restoration, EPA-440/5-79-001, pp 161-167.

Shapiro, J., LaMarra, V., and Lynch, M. 1975. "Biomanipulation--An Ecosystem

Approach to Lake Restoration," Water Quality Management Through Biological

Control, P. Brezonik and J. L. Fox, eds., Univ. of Florida, Gainesville,

pp 85-96.

Shireman, J. V., and Maceina, M. J. 1981. "The Utilization of Grass Carp,

Ctenopharyngodon idella Val., for Hydrilla Control in Lake Baldwin, Florida,"

J. Fish. Biol., Vol 16, pp 629-636.

Uttormark, P. D., and Hutchins, M. L. 1980. "Input-Output Model as Decision

Aids for Lake Restoration," Water Res. Bull., Vol 16, pp 494-500.

Vollenweider, R. A., 1975. "Input-Output Models with Special Reference to

the Phosphorus Loading Concept in Limnology," Schweiz Z. Hydrol., Vol 37,

pp 53-84.

Welch, E. B. 1981. "The Dilution/Flushing Technique in Lake Restoration,"

Water Res. Bull., Vol 17, pp 558-564.

25

AZ A%%

°•9
SEDIMENTATION AND EFFLUENT CONCENTRATION P

OF SOFT CLAY ON RECLAMATION WORKS

Yoshiharu Watari, Norlyoshi Aritomi, Nobumasa Mar11

Japan Bottom Sediments Management Association

ABSTRACT

N This paper establishes a basic design standard

for the disposal of effluents in a containment area.

Field investigations and model tests were conducted to

clarify the flow patterns and settlements of the discharged material. By considering the results obtained

by these investigations, we discuss the method of estimation for effluent suspended solids (SS) concentration during dredging and reclamation works.

The basin in front of a spillway is an ideal sedimentation basin. The settling tests that introduced

the idea of overflow rate in an ideal sedimentation

basin gave a good correlation between overflow rate

and SS residual ratio. If settling tests of the bottom sediments are carried out in advance, from which

correlation coefficients are obtained, an approximate

estimation of effluent concentration can be determined

by the regression equation corresponding to the

reclamation progress.

INTRODUCT ION

Dredging sea bottom sediment and placing it into diked containment areas,

thus preventing water pollution, is important for the preservation of the environment. Recently in Japan, it has been very common to dredge soft clay

that contains a large amount of oil or organic substances. A very important

problem is management of the effluent SS concentration--this management must

be incorporated in the design and execution of dredging and reclamation work.

This paper describes the behavior of effluents with the progress of sedimentation at the pump dredging and reclamation site, based on field investigations and the model tests of the containment area.

This paper also describes a simplified method of estimating the effluent

concentration in the containment area by applying a settling test using a cylinder. Because settlement and sedimentation change in the containment area in

a very complicated fashion with the progress of reclamation, there is a limit

in accuracy of estimation from laboratory tests involving a number of assumptions. However, the method to estimate the approximate effluent SS concentration derives its utility from its simplicity and speed of test execution.

26

r e
FIELD INVESTIGATION

Outline of the Project

The project for the investigation is the dredging and reclamation works

of about 400,000 m3 in dredged volume by a cutter suction pump dredger of

4,000 ps in horsepower. The site is located in Imari Port in Kyushu, Japan.

Figure I shows the site location of the dredging and reclamation area and

Table I gives the specifications of the project.

Sampling po ints

Dredging area

43 02 4 Sedimentation basin

Contaiment area

4' N3-out let

Kyot or

-Tokyo

Osaka , 0 100 2(X) 300 400O ~ ']|i

Figure 1. Plan of the dredging and reclamation area

Method of Investigation

To determine the soil characteristics, the sea bottom sediments around

the dredging area were sampled by penetration of an acrylic tube, 75 mm in

* diameter and 850 mm in length. The sediments were also sampled at the outlet

of the conduit pipe to determine wet density and unit weight. Turbidity in

the containment area was measured by three submersible turbidimeters.

Measurement points were 50 cm below the water surface and I m above the

bottom. Effluents at the spillway were sampled three times a day throughout

the construction period and brought into the laboratory for suspended solids

test. Flow pattern in the containment area was surveyed by tracing the locus

of a buoy.

27

.1 sd* 
TABLE 1. PROJECT SPECIFICATIONS

Item Specification

Dredged volume 389,000 m3

Area of containment 272,000 m2

p

Design thickness of 3.25 m

rec lama tion (+3.20 m from water level)

*Area of sedimentation 16,960 m 2

*basin (160 m x( 106 m)

Volume of sedimenta- 61,000 m 3

tion basin

Investigation Results

A field survey was carried out in the middle and latter periods of construction. The reclamation progress ratio was 30 to 40 percent at the middle

period and 80 to 90 percent at the latter period. Physical properties of the E

dredged material are shown in Table 2.

Figure 2 shows the contour lines of the sedimentation and the flow pattern of disposed material during the first observation (reclamation progress

ratio about 40 percent). The thick lines in Figure 2 are the depths at which

the turbidimeter (Tb) indicated more than 500 ppm (the limit of detection) and

the dotted lines are the depths measured by use of a lead. The difference

between the two lines, calculated to be about I to 2 m, is considered to be

* the height of unconsolidated sedimentation of the dredged material. Water

content of this layer was about 150 to 230 percent. The dredged mixture

* flowed toward both sides due to the higher sedimentation in front of the

* outlet. The extremes of the oblique lines in Figure 2 indicate dead zones -

where flow was very low.

Figure 3 shows the depth measured by a ruler, during the second observation (reclamation progress ratio about 90 percent). The sedimentation pro-

* gresses through almost the entire region and shows a leveled configuration.

Water content at 50 cm below the sedimentation surface was 200 to 450 percent.

From Figure 2, it can be seen that the inclination of the sedimentation surface varies from I in 250 to I in 200 in the most steeply inclined regions.

On the other hand, in Figure 3, the inclination in the latter period of the

reclamation becomes less than I in 1,000. It is presumed that the sedimentation liquefied in the containment area due to the high water content and, as a j

necessary consequence, the inclination became less steep. Actually, it was

ohserved that the sedimentation surface in the detention area located farthest

from the outlet ascended slowly with the progress of reclamation.

28

. . . . . . .
TABLE 2. PHYSICAL PROPERTIES OF THE DREDGED MATERIAL €-

Natural Ignition A

Specific Water Content Grain-Size Distribution, % Los

(;ravitv Sand Silt Clay 7

2.620 97 3 - 5 48 - 57 40 - 47 10

1 2 3 5 6 7 8

Somr 75m

first observation

ob.. D of T

jo,,, y? ,spi /way

hthr o et esue yla

ed ti bu

Fiur.2 Cnou -lneadflo atrsi th cotimetae

concntrtionaftr aout 3 h ofSettlent. Turbdit atw oinsA B n

',-C.inFigure 4 shows maredreincreasescafterou15,u45,dand 80amremfrom the5begin-

-'- ninglof the earsurment. Theegn ar peumed be thetes othat0 te17disposed

mTerialorehed tret pofIt The prpagatrin vhelocirtestg of turbidityuare *'i calcultatdionbea23ecm/secufromh ou etletento pointdAy6acm/sectfrom poind

...::::, inFigure 5 shows thred plncesibton otubiit atd 0 cnrm belowegthe . nwate sfahe; conour inTes ae also pncued. to quiahete tridty inessd"

-"" i.,sprerala riganglsit thens diha ropgaition, idcatingo theidt efflet

falwed sl toward both/ses aso hompaed th pit discargec direction duA

| ~to pthe sdmatio , inm/e frot pon the oitC

1229

.' " Fiure shos th plne dstriutio of urb Dityth of cmbeo the

*,-".,~ fswd e s l o a d o h s d s a o p ild w ath disc Dept a sudredcty ona d u

pf

.........................................

buy9

Fiue2 Cnorlie n fo aten nth-otinetae

Figure 4 hw h euto otnos ubdt esrmnsa 0c

beo.h.ae.ufae rdigwspefre ewe bot70 o1:0
VJ.

1 2 3 4 5 6 7 8

50m 5x

0.0 0 4.0 9.0 4.0 14.0 8.0

0.0 - 0.5 ____ 0.3 ____ 0.5 0.5 17.0

.0.5 O0te 0.3 _ _ 9.0

d 1.06.5 7.5Z--70510

e .-0 2.5 __ _ 3.01 17.0 13.0 11.0yN

f 50. 3.0,, .C Sedimentat ion

1 0.0 0.0 1.0 11.0

Figure 3. Depth measured by a ruler (March 2, p.m.)

250-

-ut let A

200-

150-

100-

SO-p

F..igurii!Iesutof continuous measurementof turbidity (February 17, a.m.)
1 2 3 4 6 7 8 %

i -- -

30 80 50 < I50 150 68 54

r-,) ,' ;7 1

500< 260' 2 24,

L% ". " , I

50 _ 2Er " 1? 140 A -54' 2 20. _31 d

150ppw 0V

4 38: Q2 17 221B 23 20 23 /

d

50 56 40 "- 2 Seh*mentatcs BasIn ...DeiDth of Tb ">SOOppm , %

30,,

Figure 5. Plane distribution of turbidity at 50 cm below .' .,

the water surface; contour lines are also. included (February 17, a.m )

Continuous turbidity measurements at points A to C in Figure 6 show a'iquite different tendency. In Figure 6, though the turbidity at point A, which

is almost centrally located, increases with time, the turbidity at point B and

C remains constant. -'.,

Figure 7 shows the plane distribution of turbidity and the contour lines

measured during the afternoon of the same day. Dredged mixtures on that day

spread in a radial dispersion as was shown in Figure 2; therefore, it is concluded that propagation of the dredged mixture increased the turbidity at

point A, buotnt directly to the points B or C. tyAlthough the dredging work rbgan on February 7, it was February 15 when

the effluent began to overflow ot the spillway. Variations of the effluent s

SS concentration with time show a sawtooth tendency as shown in Figure 8. The --

control limit of SS concentration at point Y In Figure 8 was 50 mg/ to a prevent water pollution. High molecular coagulants BorC were added to the effluents 

to satisfy the standard since Fehruarv 15. Some 10,50 kg of high molecular

coagulants were used. Average dosage was 26 g/cum of dredged material.

MODEL TEST OF THE (CONJAINMEN'F AREA

As the flow patterns and sedimentations in the containment area are considered to be a complicated phenomenon in which many parameters interact with

each other, a simplified model test was carried out to predict the phenomena.

o'I
500

A

BC---

400

E~300-

.200-

• : . ...." ... ........ b.

9 :00 10 :00 11 :00 12:00 13 :00

TIME

Figure 6. Result of continuous measurement of

turbidity (February 18, a.m.)

2 3 4 5 6 7 8

C , -1 Oit let

~ 9 60 SOO, 500, 220 20 35

E 10 p , Io 5 0 p-. I It

65,I Coo C C690 --- 40 6 75

I p " ..- - Opm- 

.

5 8 i _( 1 4 0 I ' 3 1 [ 2 . .4@' % 6 1 ,'

58~

C7 \8. 2 6 If8 20 B 32 41 /37

',,

2.rn - 22 30 311

91 -2 44, 14r C ----

) I8 ' 95 8 1 4 4 1 , d m ,n t t mo n B R im - t u r h d i tv

2(im ...... Delpt of Tb -) -i

Figure 7. Plane 

the water 

distribution 

surface, 

of 

contour 

turbidity 

lines 

at 

are 

50 

also

cm below A

included (February 18, a.m.). . -

".,.'

32 ..-

p%,#p

'%9 
" I i

U.

rOr

1XX-2

Sedimentation basin

105 _Y

-1I Dike

X-2 ------ ZI"

4 - Y A[,r

10 z

03 A Ae,.V

,%U

101

-V /\.."V, \* I

9 13 15 16 17 18 20 21 22 23 24 25 26 27 28 29 1 2 3 5 6 7 8

FE B. MAR.

DAY

20 40 60 80 100

.II ,,I .

Reclamation progress ratio (%) UFigure 8. Elapsed time fluctuations of the effluent SS

concentration in the sedimentation basin

Test Equipment

During the latter period of the reclamation, should the depth become

shallow, the dredged mixture spreads radially and sedimentation progresses in

" a three-dimensional mode. However, during the early or middle period, at

* rather high depths, the sedimentation can be considered as a two-dimensional

phenomenon, in the longitudinal and vertical directions. Thus a twodimensional model test using water tanks was conducted. The test equipment is

' illustrated in Figure 9.

The prescribed concentrated slurry with the sea bottom sediments and

artificial seawater, as described later, were poured from one side of the

water tank keeping a constant water head by the siphon principle. On the

other side of the water tank an effluent weir is established. Samples of the

sedimentation were taken during the experiment at points BC, DE, and (i, shown

33 5-.

, %-

"-" ," ,.-".",1" ' ,".'" " ,'. " 4" J e ' ' " """£" ' ", "' "" """-# " ""' - ~ .
in Figure 9, to measure the concentrations. The samples were taken at six

points vertically using a sampling device as illustrated in Figure 10. After

pouring the slurry, water content and grain-size analysis were performed at

points A through H in Figure 9. Table 3 shows the test conditions.

I %

140 cm

25, 7@450 = 350 125" I ' -

B C D E F G H %

I II I .. -.

Clayey Soil *.

± Y 

orflow

-Seaw

Vr Contaihe ( 3 0 s4 x65 x6S) .% 

* IJLJl

Figure 9. Outline of test equipment (all units in centimeters)

Results of Test

We attempted to clarify the effect of kinds of water on the settling

velocity of particles. Figure 11 shows the decrease of the clarified water SS

concentration with time using several different solutions. The variation of

the clarified water SS concentration of artificial seawater (commercially -,

called "Aquamarine" in Japan) shows a similar tendency to that of natural seawater. In saline solutions, the SS concentrations are larger than the other

cases; the SS concentrations in fresh water are the largest. This means that

the settling velocity of particles in seawater is greater than in fresh water

due to flocculation of negatively charged sediment particles into Mg++ or Na+

in seawater.

Figure 12 shows the grain-size distributions in fresh water and in arti- ,

ficial seawater obtained by mechanical analysis of soil using a hydrometer.

When seawater is applied to the analysis, the result shows that there are

fewer particles smaller than 5 wm; the apparent grain size becomes larger.

Therefore, for actual sedimentation in seawater, artificial seawater was selected for the n' iel test due to its similar properties to natural seawater.

Figure 13 shows the outline of the sedimentation condition 10 min after

the beginning of discharge. Discharged material reached the bottom of the

tank as a forced plume, then spread slowly in the horizontal direction. A

suspended layer in the upper region, a zone settling layer in the middle region, and a consolidated settling layer in the bottom region developed as

shown in Figure 13.

.,

34 % %

%
. ... M, . - v . ~ . -3 . .. .. . . -*, , - ,

-

isC

: I

DE

GH '

Seawater

Vinyl Tube

' Figure 10. Sampling device 3mm

of the mixture 0

E

J Guide Bar °° I w-J

. ) "..

TABLE 3. TEST CONDITIONS

Influent Diameter of Influent Velocity of Elapsed DisConcentration Inlet Pipe Loading Rate Inlet Pipe charge Time

mg/z mm ml/min m/sec min

96,300 4 250 0.33 240

J.

Figure 14 shows the vertical distributions of the concentration at points

BC, DE, and GH as a function of elapsed time. Though the water content in

each layer changed only slightly with the passage of time, it tended to increase with distance from the outlet tube. The water content distributions in

consolidated sedimentation shown in Figure 15 exhibited the same tendency.

35

.1%

I x ,.1A
.. "

% %

100 ,00 0 . "a

7-

5

7 Fresh water

3-. 5-.

1,000 / Saline soution

7 3-

S100

7-

3 

A /Seawater

10 Artificial seawater 10"

7-

5-

3-

35 57 3 57 3 -57 5 7

1 10 100 1.000 i0,000--

Time (min) "

Figure 11. Variation of clarified water SS concentration using several different

solutions (SS = 33,690 mg/I)

This tendency corresponds to the grain-size distributions of each point.

Smaller particles are accumulated in proportion to the distance from the out- .'

let tube (Figure 16). It may be noticed that the content of colloids :-"-

increased remarkably with distance from the outlet.

SETTLING TEST ESTIMATION OF EFFLUENT CONCENTRATION a.

Based on the findings of this study, we determined a simplified method

for the estimation and management of effluent SS concentration.

Relation Between Overflow

Rate and Effluent Concentration

Overflow rate is one of the most important indices in an ideal sedimentation basin in the field of water and wastewater works. Overflow rate , -"

36 %

.,9< > '.,

-''.. " '.- ,z .'-.'° .'-, °.'.'-- .

"''' ...- "-". "aa*- , -". "m .'.-",.*% . ";% ,., -.-.- •••.•°- '. ,. p : -, .-...-.-. ,-,..,-.._-* V~ - .'-, . ,p -.. .i - ,.,- ,,;, . &, - .

1 c - w.---,-..- .- -, . -..-.-.... . .- ... ,-,
Jp

100.

90

80 L

70 -in iresh water

00-

20

140

30

S-0.001 0.01 0.1 1.0

'S Grain size (mim)

Figure 12. Grain-size distributions of tested sediments

in fresh water and in artificial seawater

ivp

N- %

% &A
3 A

BC

I-'

I,'.

DE

S25-

-J7

G H 0 T- 3 Omin

60%

E 2 5 rn.120

S240

o' ---

Figure 14. Density distribution of

* sedimentation

Water content(%

100 200 300 400 500 570

E

5-.

C

L. E

19- F

2 G

0 H

Figure 15. Water content distribution of consolidated sedimentation

38

% . . .. ... . . . .' N.. 

- . I- 
'.

>.4

100

SI I .

F 7

D

Clay St ISand

-- "-I.

7 I 1 11 I I l l , I 1 l ,

0.001 0.01 0.1 "

d ( mm ) .

Figure 16. Grain-size distributions with

distance from the outlet tube .-

is expressed as the dimensional quantity Q/A where Q is the influent loading rate and A is the surface area of the sedimentation basin. An ideal

sedimentation basin is shown in Figure 17 based on basic assumptions, as .

follows : -

_a. Fluid flows only in the horizontal direction and has an equal.9 velocity at all points.

b. Concentration of suspended solids is the same at all depths."

c. The particles, once settled on the bottom, are not resuspended."'

Overflow rate is the rate of climb when fluid springs with uniform veloc- .

ity from the entire floor; therefore all particles having a faster settling

velocity than this spring velocity Q/A will be settled. This is a reason-

..

able explanation if the basin has sufficient depth, but there is a limit in..

depth to adapt this assumption due to deflection or scouring effects. From

the authors' experience, this limit is applicable up to about 50 cm in depth,

at about I to 3 hr of detention.

Overflow depths are usually designed to be to 15 cm S in actual reclama-"

tion works. At a point I0 cm below the water surface, in front of the spillway, after t sec from dredged material propagation, the particles having a

settling velocity greater than 10/t cm/sec would be deeper than 10 cm below

the water surface. If the basin around the spillwy in the cotainmlent arA

is assumed to be an ideal sedimentation basin, m divided b .0 , ide al."

39""
4. A

1% %

|£

E n n

\ .4-

Figure 17. Schematic diagram of an ideal

sedimentation basin

corresponds to an overflow rate of Q/A . Based on this point of view, we

carried out a settling test and examined the method of estimation of the

effluent concentration.

Test Equipment

The settling test utilizes a transparent cylinder with a height of 40 cm

as shown in Figure 18. Two cylinders, 60 mm and 138 mm in diameter, were used

to study the effect of diameter. The sea bottom sediments were diluted with

artificial seawater to the specified concentration in this cylinder. A turbidimeter, shown in Figure 19, was placed 10 cm below the water surface. This

turbidimeter is a transmitted light type using a luminous diode, and can measure up to 3,000 caolinite concentrations. The relation between SS concentration and turbidity has been investigated previously; therefore, the measured turbidity values were translated to SS concentrations using regression

equations.

Results of Test and Discussion

The purpose of this cylinder test is to discuss a method for the management of effluent SS concentration from the relation between overflow rate Q/A

40

% %

%*
*- . -. .WTV..JIL

10 c

Fiur 19 rnmttdlgt urbidimet yp 

41-
and SS residual ratio SS /SS obtained by the continuous measurement of

0

clarified water at a point in a cylinder. For this purpose, it is important

to measure SS concentration on a real-time basis.

Tested sediments were sea bottom silty clays as shown in Figure 12. The

relationship between SS concentration and turbidity shows a good correlation

as shown in Figure 20. Regression equations obtained were as follows:

0 < T < 150 mg/Z : SS = 1.51T - 5.5 (1) b b

150 < T :SS =1.70T -131 (2) b b

sooo

4000-

2000"

0

1000-

0

0 1000 2000 3000 4000

Turbidity (ppm)

Figure 20. Relations between SS concentration

and turbidity

Based on a slurry content of the pump dredged material of 10 to 15 percent, SS concentrations were supposed to be about 10,000 to 100,000 mg/k. The

field investigations and model tests showed that the effluent SS concentrations in the spillway became much lower than the influent concentration due to

the removal of the sedimentation. Accordingly, tests were conducted over a -

wide range of influent concentrations, as shown in Table 4.

42

F."
TABLE 4. RANGE OF INITIAL SS CONCENTRATIONS X

ON CYLINDER TESTS%

Initial Concentration

Case mg/k

1 48,800

2 29,900

3 8,510

4 7,730

5 5,250

6 4,120

7 2,780

8 1,030

9 940

10 380

Figure 21 shows the concentrations after 8 min for typical examples.

When the initial SS concentration was 48,800 mg/i, zone settling can be

V observed, but in cases when SS is less than 10,000 mg/i, the phenomenon of

zone settling is not observed.0

Figure 21. Concentrations

after 8 min of

settlement

S48800 8510 525o

From Figure 22, it can be seen that the clarified water SS concentrations

seem to be nearly equal after about 30 min of settlement. A good correlation

is found in the relation between SS concentration and elapsed time. RegressIon equations were obtained as follows:

43 4

%
SSo = 48,800 mg/ : SS = 875t - 0 .5 68 (3)

22,900 - 8,510 SS = 1,610t - 0 6 6 4 (4)

7,730 - 379 SS = 4,440t- 0 .84 1 (5) .

In Equations 3 to 5, the regression coefficient a of the equation

SS = atb indicates virtual suspended solids after I min of settlement

(t = 1) and the greater the concentration, the smaller the value of a

100,000

7-

5-

10,000 -

7-

3-

1,000

7

5

S100

.4

7 - 5--

10 i

3 57 3 57 3 57 3 57

1 10 100 1,000 10,000

Time (min)

Figure 22. Clarified water SS concentration at 10 cm

below water surface versus time

In ordinary pump dredging the SS concentration of the dredged mixture is

considered to be about 10,000 mg/., the dredged mixture settles in a very

short time, and the SS concentration is less than 10 percent of the influent

concentration. Figure 23 shows the relationship between overflow rate Q/A

which is obtained as (10/t), and SS residual ratio (SS /SS ), where t to 

44

.5 . ..*. P* . -. . . . . . .

.5 . ... .J.. .
p.

* ~93 7lng/t. VO

10 U

8510 mg/.

CO 0.2

CID 0.1

0.01 o 480g I ~ 8o0,g/Z ::

0.005

0 001 0.01 0.1 1 10

Q/A (m/hr)

Figure 23. Relations between overflow rate Q/A ,

which is obtained as (10/t), and SS

residual ratio SS./SS

1 0

t. 1 is the elapsed time and SS. 1 is the concentration at each time. These

relationships have a significant influence on the initial concentration--the

greater the initial concentration, the smaller the residual ratio becomes.

These curves can be represented by regression equations in the form given

below:

SS i /SS = a(Q/A)b (6)

As the inclination b in Equation 6 is almost identical, they can be

treated as essentially straight lines on a logarithmic graph paper. Thus, an

approximate estimation of effluent SS concentration on reclamation work can he

performed by the relation, Q/A - SS /SS as shown in Figure 23 and In Fqua1 0

ation 6, by substituting the influent loading rate 0 , influent SS concen- U.

tration SS , and effective area A

45

.4
.1

-p

Figure 24 shows the result of calculations of the significant differences ,"

in the residual ratio (during 10 to 1,000 min) by the wholly significant difference method. In Figure 24, the symbols a through g represent temporary

group names. Groups a and b are absolutely different from each other, but

group c is not recognized to be different from group cd. In Figure 24, al-,

though significant differences can be observed in the case of different initial concentrations (ex. Case 1, Case 2), there is no difference between the

case of a small cylinder and a large cylinder. Therefore, for the settling

test, we concluded that it is sufficient to use a 60-mm diam-cylinder.

2.0

1.6 X :mean

1.2 :confidence interval

0.8 e f o dee

cn 0.4- od cdT '

-o.o -.

g-0.4-

-08

S small cylinder (,)60mm

-1.2 L large cylinder < 138mm

-16

- O I I I I I I I I I I I I I I I I

S L S L S L S L S L S L S L S L S L S L

1 2 3 4 5 6 7 8 9 10 %

CASE Numhpr

Figure 24. Calculated result on significant difference of the SS residual ratio by

wholly significant difference method

CONCLUSIONS

Various findings concerning the sedimentation and effluent SS coricentrations were obtained from the reclamation work by pump dredging from field investigations and a model test. Based on these findings, a simplified method

hiaM been determined for the estimation of effluent SS concentration. Results ,.

were as follows:

46 SO%

"""-
Sedimentation and Flow

Pattern of Dredged Mixture

" The settling velocity of particles in seawater is greater than in

fresh water due to the flocculation of negatively charged sediment -

particles into Mg++ or Na+ in seawater. It is therefore better to

apply seawater or artificial seawater to investigate prototypes.

" Flow patterns of the dredged mixture are considerably affected by the %

sedimentation of large-sized particles. Smaller particles accumulate

in proportion to the distance from the outlet.

" Clarified water concentration at the spillway is affected by

variations in the flow pattern.

• Water content at 50 cm below the sedimentation surface was 200 to

450 percent. Test results indicate that the water content on sedi- '

mentation during consolidation is 200 to 600 percent. Hence, the

sedimentation at 50 cm below the sedimentation surface is considered

to result from consolidation.

• There are significant differences in the water content and the grainsize distributions of the sedimentation with the distance from the

outlet.

Estimation of Effluent '.a

Concentration by a Cylinder Test

* Zone settling can be observed when influent concentrations are more

than 10,000 mg/i, but in the case of an initial concentration less %

than 10,000 mg/k, flocculent settling can be observed.

* The clarified water SS concentrations become nearly equal after about

30 min of settlement, independent of the initial concentration.

e A good correlation can be found in relationships between SS

concentration and elapsed time as follows:

b -5

SS = at

Coefficient a changes with the initial concentration.

9 Relationships between overflow rate Q/A and SS residual ratio

SS /SS can be represented by the regression equations in the form

given below:

b

SS./SS = a(Q/A) 1 0

The regression coefficient a also changes with the initial concentration SS and the greater the SS , the smaller the value of a 0 0

9 The diameter of the cylinder has no effect on the settling pattern or

the clarified water SS concentration within the range of tested

diameters.

47

° . . - . -
- -- - 4 -. -.-- - - -

COMMENCEMENT BAY - A REMEDIAL INVESTIGATION OF

CONTAMINATED SEDIMENTS IN A MARINE ENVIRONMENT

J. D. Krull

Project Manager, Washington State Department of Ecology

Mail Stop PV-11

Olympia, Washington 98504

T. C. Ginn

Director, Tetra Tech, Inc.

11820 Northup Way, Suite 100

Bellevue, Washington 98005

R. C. Barrick

Senior Chemist, Tetra Tech, Inc.

11820 Northup Way, Suite 100

Bellevue, Washington 98005

ABSTRACT

Contamination of sediments in Commencement Bay by

toxic pollutants has caused considerable concern about

degradation of marine habitats, induction of disease

in indigenous organisms, and contamination of organism

tissues. The approach to and results of an intensive

2-year, $2 million investigation are presented. The

goals of the investigation were to determine the

extent of contamination, determine if the contaminption resulted in adverse effects to public health or

the environment, identify problem contaminants and

their sources, and identify potential remedial

actions. An extensive synoptic data set was obtained

during the investigation. These chemical, toxicity

(bioassavs), and biological effects (benthic community

structure, bioaccumulation, fish histopathology) indicators were used along with historical data to identify problem areas and problem contaminants. Sources

of problem contaminants were identified to the extent

possible using horizontal and vertical patterns of

chemical 

data, information 

contamination, 

on dredging 

available 

history, 

source 

knowJedge 

loading 

of

I

environmental fate processes, and knowledge of past

and present industrial activities in the area.

Problem areas, problem contaminants, and contaminant

sources were prioritized such that resources could be --

effectively allocated for corrective actions.

48

%9
-U

INTRODUCTION

Commencement Bay is an urban-industrial embayment in south-central Puget

Sound (Washington). Urbanization and industrial development began in the area

during the final quarter of the 19th century. Dredge and fill activities have

transformed the broad tideflat that once existed at the mouth of the Puyallup

River into a series of industrialized waterways and an active port facility.

Past and present industrial and commercial operations located in the area

include pulp and lumber, ship building, metal plating, chlorine and other

chemical production, aluminum smelting, oil refining, copper smelting and

refining, concrete production, food processing, shipping, ship dismantling,

marinas, scrap yards, railroads, and a number of other storage, transportation, and manufacturing facilities.

The presence of these operations and the urban growth of the surrounding

area have resulted in the release of contaminants into the marine environment.

The contaminants include metals (e.g., arsenic, lead, zinc, copper, and

mercury) and organic compounds [e.g., polycholorinated biphenyls (PCB),

dibenzofurans, chlorinated pesticides, plasticizers (pthalates), and polynuclear aromatic hydrocarbons (PAH)]. Over 425 point and nonpoint discharges

have been identified in the area, each of which is a potential source of

contamination.

Concern about the potential effects of sediment contamination in Commencement Bay (e.g., toxicity to marine life, induction of disease in fish,

and potential human health impacts from consumption of fish and shellfish)

resulted in designation of the area as a National Priorities List site by the

US Environmental Protection Agency (EPA) under the Comprehensive Environmental

Response, Compensation, and Liability Act. In April 1983, the Washington

State Department of Ecology (WDOE) and the EPA entered into a Cooperative

Agreement. EPA provided funds for the investigation and WDOE was designated

lead agency.

GOALS AND OBJECTIVES

The goals of the investigation were to determine the extent of contamination, determine if contamination resulted in adverse effects to public health

or the environment, identify problem contaminants and their sources, and identify potential remedial actions. The specific objectives set were:

a. Define a problem sediment.

b. Apply definition of problem sediment to delineate problem areas.

c. For problem areas, determine problem chemicals.

d. For problem chemicals, determine problem sources.

e. Prioritize problem areas, problem chemicals, and problem sources.

f. Assess impacts of fish and crab consumption on human health.

Document alternative methods of dredging, handling, and disposing

of contaminated sediments.

49

% ~ .. .%~*.. % % ~
S1-r1, , w- IL.A k- _Al 4_N~X %V - k

h. Initiate a decisionmaking framework for managing the disposal of

contaminated sediments.

i. Identify potential remedial alternatives.

This paper will deal mainly with objectives a through e. Discussion and

results of objective f through i may be found in Tetra-Tech (1985), US Army .

Engineer District, Seattle (1985), US Army Engineer Waterways Experiment

Station (1985), and Versar, Inc. (1985).

APPROACH

The major elements of the decisionmaking approach developed for the 4P.

investigation are presented in Figure 1. The first step in the process was to

determine the types of information needed to best meet the objectives of the

* project (i.e., determine problem areas, problem chemicals, problem sources,

and a means of ranking these in priority order). Because definitive causeeffect information and sediment quality criteria were not available for the

marine environment, it was necessary to collect information on both chemistry

* and biological effects. The indicators chosen were chemical analyses of

- sediments, toxicity tests of field-collected sediments (i.e., amphipod bloassays as a lethal indicator and oyster larvae bioassays as a sublethal Indicator), bioaccumulation of contaminants in English sole (arophrys vet .,) .,

and cancrid crabs, and biological effects (i.e., alterations of benthic

invertebrate assemblages and prevalences of liver lesions in English sole).

Ancillary information determined necessary included physical characteristics

of the sediments (e.g., grain size), organic content of the sediments, and a

measure of the oxidation state of the sediments. Chemical analysis of water

column particulates was also determined to be useful in making judgments on

contaminant movement in the project area.

The next step in the process was to review and evaluate the existing

data base. A sampling and analysis plan was then developed. Stations were

located to fill gaps in the historical data base, to define more precisely

areas of known contamination, and to evaluate gradients of contamination and

effects relative to suspected sources of contamination.

A project reference area was selected so that Commencement Bay data could

be compared with data from an embayment judged to have relatively uncontam- .

inated sediments. The project reference area is distant from the industrialized areas of Puget Sound. Concentrations of chemicals in the sediments

sampled from the project reference area were comparable or lower than those in

other Puget Sound reference areas. .-

The sampling plan was implemented by an intensive field survey. Results ,'

of the field survey were used to characterize the project area (Figure 2) on A

several degrees of spatial resolution:

a. Overall project area.

b. Study areas (the eight waterways and the Ruston-Point Defiance

shoreline).

c. Problem areas (area within segments determined to be a problem). "

50 "". "

--
77.

o

Co

L 22

U. S.) - Ci) LCon

uI).)

-w Z

CC~j

w C -jCE CL I.

U ) zL) C co

0) e

0

0 z 0

0 0.

W (n- U) mW

o) <J C.) - (A _ ><z>u. ri

'I w i

Z0L(

C) C U zuj W 

D0 

)

Z 2 u w >- )

Z 'a.

*l 5 c

20 0 cp . > U) :j 
4-44

o cc

4'4

00

Goo

I- 0

ara.

-0 *.- 

j CNJia 

52-
Sediment contamination, toxicity, bioaccuimulat in,. i,,

were described by establishing an index for each CTIVir,,Tt

indicator investigated, calculating "elevations ah,:v r'.' ,

each indicator, and testing each EAR for signit icatnce. f Al ' ,•

indicator variable at a Commencement Bay area and at th, r, t,,rT- e.

example, an EAR = 5 indicates that the variable was five t ir - .' ,' -

mencement Bay than in the reference area. For toxi( itV, , !Fii it i.. ... ., Ni 

biological effects, a significant EAR was one that was stat i: dtic, :, rt

(P < 0.05) from the project reference area (except lor benthic .!t,.rt ioulwithin the waterways, where Blair Waterway was used in lieu ot the pr(, ect

reference area). For sediment chemistry, the EAR was determined t- he signiticant if the contaminant value exceeded the maximum value in an, , -evera]

reference areas throughout Puget Sound.

In addition to characterization of the project area as described ;ibove,

results of the field survey were also used to develop quantitative relationships among sediment contamination, toxicity, and biological effects. These

analyses were conducted primarily to determine levels of sediment contamination above which significant toxicity or biological effects would be expected

to occur, and to identify contaminants suspected of causing the observed

effects. Results of the quantitative relationships analyses were used to help

define boundaries of problem areas and to identify potential problem

chemicals.

EAR for study areas and segments were assembled into action assessment

matrices. These matrices display the indices (EAR) for each environmental

variable or indicator for each study area or segment under consideration.

Also displayed is whether the EAR is significant or not significant and the

reference value from which the EAR was determined. Action level guidelines

were then applied to identify study areas and segments of concern. The

action level guidelines defined the minimum levels and specific combination of

environmental indicators required before problem area definition could proceed. This threshold for action was always exceeded if at least three of the

five indicators of sediment contamination, toxicity, and biological effects

were determined to be significantly elevated above reference conditions in an

area. Each study area or segment of concern included either a problem area

that extended over most of the study area or segment, or a "hot spot" of major

significance within the study area or segment.

After areas of concern were defined, problem areas were identified, and

their spatial extents were determined. Problem area definition incorporated

all available data, including historical data and use of results of the

quantitative relationships among indicators developed as part of the present

study. Problem areas were then ranked according to their most extreme levels

of contamination, toxicity, and biological effects. Priority for evaluation

of potential sources of contamination was based on this ranking. Potential

problem chemicals were also identified and ranked at this point.

After problem areas and potential problem chemicals were identified and

ranked, potential sources of contamination were evaluated. Final prioritization of problem areas recommended for remedial action was then determined on

the basis of the relative magnitude of problems in each area, the spatial

extent of each area, and the level of confidence that sources of potential

problem chemicals were accurately identified.

53

. . . . .
The efforts of source identification integrated a large data base on

potential contaminant sources, observed contaminant levels in water and

sediment, and ancillary information. Some of the most valuable information

utilized in source identification included:

a. Spatial gradients of contamination in surficial sediments.

b. Vertical gradients of contamination in sediment cores. 3

c. Analyses for the contaminant(s) in discharges.

d. Dredging history.

e. Environmental fate processes.

f. Industrial activities.

APPLICATION OF APPROACH AND RESULTS

Action Assessment Matrices

An example of an action assessment matrix is shown in Table 1. These

matrices were prepared on both a waterway (area) basis and on a segment basis 4

in which major waterways were divided into three to five smaller areas. The

matrices display the magnitude of the indicators (elevations above reference)

and whether or not the EAR value is significantly different from reference.

Reference values are also displayed so that absolute values of indicators may

be determined. The indicators are:

a. Sediment chemistry

- Selected metals and organic compounds .

b. Sediment toxicity

- Amphipod bioassay

- Oyster larvae bioassay

c. Benthic infauna

- Total benthos abundance

- Polychaete abundance F7"

- Mollusc abundance

- Crustacean abundance I.

d. Fish pathology

- Hepatic neoplasms, preneoplastic nodules, megalocytic %

hepatosis, nuclear pleomorphism

e. Fish bioaccumulation

- Selected metals and organic compounds

In all Commencement Bay study areas, average concentrations of one or

more chemicals exceeded the range of concentrations found in Puget Sound

reference sediments (Table 1). However, surface sediment contamination

throughout Commencement Bay was variable both in concentration and composition. lowest concentrations of chemic;ls were found in Blair and Milwaukee"

54

. . .
k% .

NI

TABLE 1. ACTION ASSESSMENT MATRIX OF SEDIMENT CONTAMINATION, '

SEDIMENT TOXICITY, AND BIOLOGICAL EFFECTS INDICES

FOR COMMENCEMENT BAY STUDY AREAS

S T U 0 A R EA E LE V AT 1 0 NSa..0

REFERENCE

VARIABLE Hylebos Blair Sitcum Milwaukee St. Paul Middle City Ruston VALUEb .,I1

SEDDEWI OENISTRYN

Sb 10. 4.0 8.0 3.6 4.2 93 7.0 510. 110. ppb

As 12. F-76[Tr?]11 3.6 2.2 9.6 B7.5 620. 3370. ppb

Cd 2.4 1.9 1.7 1.7 2.8 5.5 27. 950. ppb

Cu*Pb.Zn 10. 4.8 5.5 18. 22. 120. 35000. ppb Hg < 3.7 5.0 3.8 5.1 26. 10. 160. 40. pp, Ni 0.7 0.6 0.8 0.8 1.4 2.8 1740. ppb

Phenol <'6.4 ' 5.2 4.3 ~ 1 1. 11. 9.4 4.5Z < 33 pp

Pentachlorophenol 1.7 2.3 < 2.1 U 1.9 1.9 CT10 U 33. ppb

LPAH '45. (2. '68. '60. '<7-7 10 120. '87. ( 41. ppb HPAH <120. '42. '65. <68. <27. 9 <140. 85. < 79. ppb

Chlor. benzenes 9.9 < 4.4 2.6 2.5 < 6.1 < 9.0 < 3.3 U 21. ppb

Phthalates . 0.66 c 0.56 5 1 7.1 4 ( 280. ppb PCBs 7. 1 1. 6.0 ppb

4-Methylphenol 7. . 10 113. 30 3.1F-T1 331 <1 13. ppb Benzyl Senzoic alcohol acid 0 [22 23. <.A. i 1.2 U 

< 140. 10. ppb ppb

%

Dibenzofuran 2 25 L7 3..:2 U 3.7 ppb

Nltrosodiphenylanine) .3 U 1.0 U 1.2 ' 1.0 U 4.1 ppb

Tetrachloroethene [12.J --- U 1.0 . 1. . U 10. ppb

SIDDENT TOXICITY

DAmphipod bioassay 2. 1.2.11. 2-7 r 37993%

*Oyster bioassay 2. . . . 1 1 .6 22 3. INFAUWAc

Total benthos 1.2 1.0 0.7 0.8 1.9 1.5 0.7 0.6 d * m Polychaetes 0.6 1.0 0.4 0.7 1.5 0.7 0.8 0.5 d ."

Crustaceans 1.5 1.0 3.8 0.4 1.0 1 .6 . 0.7 d

FISH PAThOLOGLesion prevalence 3 2 3 2 2.7 1.7 2.1 6.7 %

FISH 4IOACCUJULATION

*Copper 5.6 1.0 ET 2. -7 1.0 3.8 25 U 38. ppb

Mercury 0.93 8 1.6 1.3 0.82 0.96 U 55. ppb

Naphthalene0.6, 0.41 0.33 rf.- 0.19 0.19 4.1 0.19 < 54. ppb P Phthalates ,se .2 70. 0.5L0. .6 0.41 0.41 6.7 5.6 < 74. ppb ., .7, -.-- 1.9 < p36. .., DOE 3.4 1.7 1.7 1 I. 2.9 < 1.8 ppb

a Boxed numbers represent elevations of chemical corcentrations that exceed all Puget Sound reference area values.

and statistically significant toxicity and biological effects at the P<0.05 significance level compared with reference

conditions. The "U" qualifier indicates the chemical ws undetected and the detection limit is shw. The "0 qualifier

indicates the chemical was undetected at one or more stations. The detection limit Is used in the calculations.

b Elevation aove reference (EAR) values shown for each area are based on Carr Inlet reference values for each variable -

except for benthos (see footnote d).

t Infauna EAR are based on the elevation in biological effects represented by reductions in infaunal abundances

relative to reference conditions. EAR for all other variables reflect an increase in the value of the variable at

Commencment Bay compared with reference conditions.

d Different benthic reference values were used depending on sediment grain size.

e Locations where PCB concentrations are significantly elevated also pose a significant health risk to the exposed

populat ion.

"7A

5 5

'.-* ,,'.'.-'-'.-',.'".'., .,~ ,.-U,,. .*, ' ' %;- . . -. -.-.. -.... .... -. ..... . . . .
Waterways, and at stations located in deeper waters outside of the waterways.

Highest chemical concentrations were typically found adjacent to point source

discharges. An exception was PCBs, which displayed a more patchy distribution

not always associated with a particular point source. Highest PCB concentrations were found in Hylebos Waterway [2,000 wg/kg dry weight (DW)]. At some

stations, concentrations of selected chemicals exceeded reference conditions

by several orders of magnitude. The highest concentration of PAH

(35,000 pg/kg DW) was found in sediments near the head of Hylebos Waterway.

At the mouth of the same waterway, chlorinated butadienes were found at concentrations up to 65,000 wg/kg DW. Concentrations of alkylated phenols

exceeded 96,000 ig/kg DW in sediments adjacent to the main outfall of a pulp

and paper mill at the mouth of St. Paul Waterway. Metals contamination was

greatest in sediments adjacent to the main outfalls of the now closed ASARCO

copper smelter on the Ruston-Point Defiance shoreline. Maximum concentrations

of four metals [arsenic (12,000 mg/kg DW), antimony (420 mg/kg DW), copper

(14,000 mg/kg DW), and mercury (52 mg/kg DW)] all exceeded 1,000 times reference conditions in these sediments.

As is indicated in Table 1, there are also distinct differences among the

study areas in the kinds and magnitudes of biological effects. Lowest sediment toxicity and effects on infauna were observed in Blair and Milwaukee

Waterways. Overall, the waterway benthic assemblages were dominated by high

abundances of polychaetes. However, areas of extreme biological effects

(i.e., almost 100-percent response in bioassays or nearly complete absence of

benthic infauna) were found in isolated areas adjacent to industrial facilities near the mouth of St. Paul Waterway and along the Ruston-Point Defiance

shoreline. English sole from five of the eight study areas had significantly

elevated prevalences of one or more serious liver lesions. The highest liver

lesion prevalence of about 40 percent was measured in Middle Waterway (compared with 6.7 percent in the reference area). Relatively few of the sediment

contaminants detected in Commencement Bay were measured at elevated concentrations in English sole muscle tissue. PCBs were detected in most fish tissue

samples and were measured at highest concentrations (approximately 10 times

reference) in City and Hylebos Waterways. PCBs were also the contaminants of

greatest concern relative to potential effects on human health from seafood

consumption.

Problem Chemicals

e' I

Quantitative relationships among the independent contaminant, toxicity,

and biological effects variables were evaluated to meet two objectives: -- V

a. Determine levels of sediment contamination above which significant

toxicity or biological effects would be expected.

b. Identify problem contaminants from the numerous contaminants

detected in Commencement Bay sediments.

Both statistical and nonstatistical approaches were used to evaluate

whether toxicity or biological effects increased with increasing sediment

contaminant concentrations. In this study, It was assumed that contaminants

displaying monotonically increasing relationships with toxic or biological •

56 "

%9
r

effects have a higher relative priority (i.e., a higher potential for being a

? causative agent) than do contaminants displaying no discernible relationship

with biological effects.

Where synoptic biological and chemical data were collected, significant toxicity in both the amphipod mortality and oyster larvae abnormality bio- ,.

assays as well as benthic effects (i.e., depressions of abundance of total

taxa, Polychaeta, Mollusca, or Crustacea) were observed at all but one station

where the DW concentration of at least one contaminant exceeded 1,000 times

reference conditions. The exception was at one station where trichlorinated

butadiene concentrations were nearly 2,000 times reference conditions, but..

neither bioassay nor any benthic effect was significant. In other sediments

without significant toxic responses or benthic effects, concentrations of

organic compounds (other than chlorinated butadienes) ranged from I to

<400 times reference conditions, and concentrations of metals were <50 times

reference conditions.

Sediment toxicity and the number of significant benthic effects were

highest in the most chemically contaminated study areas. Typically, toxicity

increased and abundances of major taxa decreased with increasing concentrations of some contaminants over the entire study area. A common characteristic of these relationships was that at lower chemical concentrations, there

was considerable scatter in the magnitude of sediment toxicity and taxon

abundances. When trends were observed, the minimum toxicity observed at a

given concentration of a chemical increased and the maximum abundances

decreased at higher contaminant concentrations. When data from all study

areas were plotted together for a given contaminant, there was no clear trend

in the values of maximum toxicity or minimum abundances over the concentration

range of the contaminant. Thus, it is concluded that no one contaminant or

contaminant group correlated with the effects observed in all areas.

In some cases, there was random scatter in the values up to a certain

contaminant concentration. Above that concentration, there was a rapid change

to uniformly high toxicity or low abundances at the few most contaminated

sites. If the high contaminant levels were associated with the effects

observed, the abrupt change in the scatter suggested an "effect threshold" for

the contaminant.

The synoptic chemical, toxicity, and benthic infaunal data for 52 Commencement Bav stations were examined for each contaminant of concern to evaluate effect thresholds. An example of this approach using lead data is shown

in Figure 3. In this case, the available data indicated that significant

toxicitv or benthic effects did not occur when sediment lead concentrations

were below 11 mg/kg DW (EAR = 1.2). This level defined a "potential effect

threshold." This threshold was termed "potential" because toxicity or benthic

effects were found at some, but not all, of the stations with higher lead

concentrations. The effects observed at these stations could have resulted

from other contaminants or conditions.

Toxicity "apparent effect threshold" (AFT) was defined as the lowest

contaminant concentration above which significant toxicity was observed at all

stations. An analogous benthic AFT was defined as the lowest contaminant

concentration above which significant benthic effects occurred at all sta- 0

tions. For leaid, the toxicitv AfT was -6n mg/kg DW (AR = 72) and the

7" "
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benthic AET was 300 mg/kg DW (EAR = 33) (Figure 3). The effect thresholds

were termed "apparent" because significant toxicity or benthic effects were ..*

not found at some stations with equal or lower lead concentrations, while

significant sediment toxicity or benthic effects were found at all stations

with higher concentrations. These empirical relationships do not prove that

contaminants found above an AET were responsible for the observed toxicity or

benthic effects. However, within the limits of this data set, chemicals

present above these concentrations were associated exclusively with problem

sediments having significant toxicity or depressed benthic infaunal abundances

(or both). Because of this association, all chemicals present above toxicity

or benthic AET were defined as problem chemicals requiring further evaluation.

.

The approach shown in Figure 3 was used to identify toxicity and benthic

AET for all chemicals of concern. AET expressed on a DW basis are summarized

for metals, organic compounds, and conventional sediment variables in Table 2.

AET were exceeded by a number of chemicals at most of the 29 stations

exhibiting statistically significant biological effects. All 6 of the

29 stations where neither AET was exceeded were unusual in that only one of

the biological indicators showed a response. Most of these six stations

exhibited toxicity by the amphipod bioassay only, and the toxicity may have

been related to the high percentage of fine-grained material (>80 percent) at

each station. The difference in thresholds for toxicity and benthic effects *"

for several chemicals suggests that both bioassays were more sensitive to

organic compound contamination, and that benthic infauna depressions were more

sensitive to metals contamination.

AET were also calculated for normalizations to organic carbon and percent

fine-grained material. For most sediments with multiple toxicity and benthic

effects, chemicals exceeded an AET regardless of normalization.

Gradients of effects were analyzed for study areas having a sufficient

number of stations with biological measurements to allow such analyses. Five -

such areas were analyzed. Strong relationships were observed for a few chemicals that were present at concentrations above an AET. Exposure-response

relationships were found at selected sites for the following chemicals: PCBs,

4-methylphenol, PAH, mercury, lead, zinc, and arsenic.

Problem chemicals are defined as those exceeding an AET. Problem

chemicals were further prioritized into three categories:

a. Priority I - Present above an AET, with distribution corresponding to

observed toxicity or benthic effects gradients.

b. Priority 2 - Present above an AET at more than one station in the

problem area, with no apparent relationship to toxicity or benthic

effects gradients, or insufficient effects data were available for

evaluation of gradients.

59

j. % -- , h

% %.'r'."%
TABLE 2. APPARENT EFFECT THRESHOLDS (AET) FOR SEDIMENT

CONTAMINANTS AND CONVENTIONAL VARIABLES

Toxicity, Benthic Effects,

Metals AET, mg/kg DW AET, mg/kg DW

Antimony 5.3 3.1

Arsenic 93 85

Cadmium 5.8 5.8

Copper 310 310

Lead 660 300

Mercury 0.59 0.52

Nickel 39 39

Zinc 490 260

Toxicity, Benthic Effects,

Organic Compounds AET, ug/kg DW AET, pg/kg DW

Phenol 420 1,200

2-methylphenol 63 72

4-methylphenol 670 670

LMW aromatic hydrocarbons 5,200 5,200

HMW aromatic hydrocarbons 12,000 17,000

Chlorinated benzenes 270 400

Chlorinated butadienes* >47,000 >47,000

Total phthalates 3,400 5,200

Total PCBs 420 1,100

Benzyl alcohol 130 130

Dibenzofuran 540 540

n-Nitrosodiphenylamine 28 28

Tetrachlorethene 140 140

Ethylbenzene 37 37

Total xylenes 120 120

Conventional Variables Toxicity, AET Benthic, AET

Total volatile solids, % 22.2 22.2

Total organic carbon, % 15.1 15.1

Nitrogen 0.28 0.28

Oil and grease, mg/kg 2,200 4,300

* No station exhibiting toxicity or benthic effects had concentrations

exceeding these levels.

60

,.. %'"
C. Priority 3 - Present above an AET at only one station within the .

problem area.

Priority of Problem Areas

After source evaluations (which are not presented in this paper but may %

be found in Tetra Tech (1985)), problem areas were ranked so that resources

could be effectively allocated to remedial actions. The ranking was based on

a quantitative evaluation of:

a. The environmental hazard indicated by the problem area .

contamination, toxicity, and biological effects. .

b. The spatial extent of each problem area.

c. The confidence that sources of problem chemicals in each problem

area had been accurately identified.

The spatial extent and general priority for source evaluation of all

problem areas identified in Commencement Bay are summarized in Figure 4. At

the highest priority sites, all three site-specific indicators were significant. Of the twenty-one problem areas, eight received the highest priority

for source evaluation, including three within Hylebos Waterway, two within

City Waterway, one within Sitcum Waterway, one within St. Paul Waterway, and

one along the Ruston-Point Defiance shoreline. The second priority sites are

"hot spots" where chemical contaminants exceeded an AET, and both bioassays

were significant or multiple benthic depressions were observed within the

problem area. Four problem areas received second priority for source evalua- -.

tion, including one within each of Hylebos, Middle, and City Waterways, and at *.

a single station along the Ruston-Point Defiance shoreline. Third priority

sites include those where chemical contaminants exceeded an AET, and one of

the bioassays was significant or a single benthic taxon was significantly

depressed. The lowest priority sites for source evaluation include those

areas where no sediment toxicity or benthic effects were observed, but where

AET applied to available chemical data suggested that toxicity or benthic

effects would have been found had biological data been collected.

CONCLUSIONS

The complex task of dealing with chemical contamination of sediments is

complicated by the lack of criteria for sediments and the lack of scientific

cause-effect relationships between chemical contamination and effects on

marine biota. The approach used for the Commencement Bay project was successful in defining problem areas and potential problem chemicals. Determination

of problem sources was partially successful. The approach also generated a

starting point for development of numerical sediment criteria, i.e., the

"apparent effects thresholds." -

61

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'I-:

REFERENCES .-_

Tetra Tech. 1985. "Commencement Bay Nearshore/Tideflats Remedial Investigation," prepared for Washington Department of Ecology and US Environmental

Protection Agency. Tetra Tech, Inc., Bellevue, Wash.

US Army Engineer District, Seattle. !985. "Evaluation of Alternative Dredging Methods and Equipment, Disposal Methods and Sites, and Site Control and

Treatment Practices for Contaminated Sediments," prepared for Washington State

Department of Ecology, Seattle, Wash.

US Army Engineer Waterways Experiment Station. 1985. "Decisionmaking Framework for Management of Dredged Material: Application to Commencement Bay,

Washington," prepared for Washington State Department of Ecology, Seattle,

Wash.

Versar, Inc. 1985. "Assessment of Human Health Risk from Ingesting Fish and

Crab from Commencement Bay," EPA 910/9-85-129, Springfield, Va.

•%-

I%

64-

r5M'

-.
CONTAMINANT MOBILITY AND ENGINEERING DESIGN

AT A NEARSHORE CONFINED DISPOSAL SITE--

PORT OF SEATTLE TERMINAL 91 SHORT FILL

Douglas A. Hotchkiss, Wade W. Watson

Port of Seattle

PO Box 1209 % %

Seattle, Washington 98111

ABSTRACT

Though the use of a slip fill as a containment

site for mildly contaminated dredged material disposal

is not unprecedented, the agreements between the Port

of Seattle and the regulatory agencies concerning the

long-range monitoring and the remedial actions plan

are unique. The Port of Seattle's Terminal 91 Short

Fill must serve a dual purpose. The fill provides the

additional Terminal 91 area required by the major

tenant. The fill also serves as a disposal site for

mildly contaminated dredged material unsuitable for

open-water disposal from other Port terminal expansion

projects. Both goals are complicated by the existing

elevated street structure across the head end of the

slip, which has necessitated a berm at both ends of

this slip fill. As a result a pond is created between

the new fill and the old end of the slip. The Port's

preferred construction option is disposal of mechanically dredged sediments behind berms of clean structural grade, well sorted, sandy gravel. This will

contain the sediments while allowing dewatering of the °

dredged material through the relatively permeable

berms.

The Port was initially faced with regulatory

agencies unable to appraise the Port's preferred construction option in light of heightened concern over

Puget Sound and the lack of field data on contaminant

mobility in nearshore disposal sites. A researchlike

approach was worked out where the Port did an extensive computer model analysis necessary to apply the

existing information to the particulars of the Terminal 91 site. After this showed the option acceptable,

the Port, in coordination with the regulatory agencies, designed the Criteria, Thresholds, Monitoring,

and Remedial Actions Plan. In addition to the monitoring, the Plan defines the criteria under which

containment will be judged, the trigger thresholds,

and the remedial actions to be taken if the site does

not perform as designed and modeled. This Plan will,

through extensive monitoring, study the effectiveness

65

Lr 0.
.,

of the fill at minimizing contaminant mobility. It

will verify the preproject modeling and reevaluate

long-range predictions. This example provides a reasonable approach to pursuing a project when faced with

environmental concerns and a lack of directly applicable data.

.0

INTRODUCTION

The project, known locally as the Terminal 91 Short Fill, is the Port of

Seattle's plan to combine the construction of additional terminal area for the

major tenant (Nissan) and the need for a disposal site for mildly contaminated

dredged materials. Terminal 91 is a mixed-use terminal owned by the Port of

Seattle. It has an upland area of approximately 100 acres and has a unique

* configuration including two parallel piers, each with a length of approxi-

* mately one-half mile (Figure 1). The piers have an earth-fill central core

with timber, piling-supported aprons around the perimeter. The Short Fill - project consists of an approximate 5-surface-acre earth fill at the north end

of the waterway between the piers. The purpose of this project is to provide

both the additional space at Terminal 91 and a disposal site for mildly contaminated dredged materials from other terminal expansions, along the Duwamish

Waterway.

BACKGROUND

Recent history of dredged material disposal in Seattle may be helpful in

understanding the project. Dredging at the Port of Seattle has been done predominantly as a part of terminal construction. This dredging has been necessary to provide adequate berth depth and to provide structural stability along

the shoreline. Maintenance dredging requirements have been minimal. Histori-

* cally, dredged materials have been dispose" in deep water in Elliott Bay, or

used as fill in terminal construction. In recent years we have become more

concerned with the water quality impacts of dredging. Initially, that concern .

was limited to water column effects during dredging and disposal. We monitored dredging and disposal operations for changes in water quality such as

pH, dissolved oxygen, turbidity, and release of metals and polychlorinatedbiphenyls (PCBs). We did not detect significant degradation of the existing

water quality regulations during those operations. The discovery that the

beds of our waterways have accumulated chemical contamination has led to increased concern for proper disposal of dredged materials and the long-term

impacts involved. The sediment contamination is caused by a multitude of

sources (industries, highways, farms, and residences) and carried to the

waterways by direct discharge, combined sewer overflow, and storm runoff.

When we proceed with construction of marine facilities, we are forced to deal

with these mildly contaminated sediments. A major difficulty that we have

encountered is that there are no generally accepted standards for proper disposal of mildly contaminated dredged materials. We have experienced a rapid

evolution in what is considered acceptable for disposal of dredged material.2

Less than 4 years ago we were disposing of mildly contaminated dredged materials within a shoreside fill with little chemical testing and no ongoing postdisposal monitoring. Today, for the Terminal 91 Short Fill, we are

subjecting the proposed dredged materials to extensive chemical testing and

66
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predisposal, site-specific contaminant mobility analysis, as well as preparing

the substantial monitoring and remedial action plan which is the subject of

the second portion of this paper. ,

ENGINEERING DESIGN

The following is a brief description of the engineering and construction

of the Terminal 91 Short Fill (Figure 2). Two containment berms are under --

construction between the piers at each end of the fill. The berms are approximately 55 ft high (18 ft above mean lower low water (mllw)) and are constructed of well-sorted sandy gravel material. The slopes are 2H:IV and are

covered with riprap. The berms are constructed in lifts. The riprap is

placed first to help stabilize the sandy gravel material that is then deposited in the lower lifts by bottom dump barge.

It was necessary to locate the north berm 75 ft south of the elevated

street structure at the head end of the slip to prevent downdrag on piling *1 -

which supports the structure. Consequently, a pond will be created which will

require surface aeration and possibly mixing to prevent stagnation. The south

berm will be constructed initially with a 100-ft-wide notch in the center down

to -6 ft mllw. This will allow the bottom dump barges to be floated between

the berms for disposal. A turbidity curtain is to be drawn across the notch

during the disposal. When the contaminated fill rises to within 4 ft of the

notch elevation, the notch will be raised to +0 ft mllw, and then on to final

grade +18 ft mllw. This will minimize the loss of contaminants by overtopping P -

due to the surge from the disposal. All of the mildly contaminated dredged

material placed at the site will be dredged and deposited by mechanical means.

After the contaminated dredged materials are placed within the berms, they

will be capped with a minimum layer of 10 ft of sandy gravel fill. This will

serve to surcharge the fill and promote dewatering of the dredged material % %

prior to paving the surface with asphalt concrete.

CONTAMINANT MOBILITY

Original Design

The proposed design's ability to restrict contaminant mobility was based % NI

on the tendency for the typical contaminants found in Duwamish sediments to

remain adsorbed onto the sediments. Therefore, if the sediment was held in

place by the well-sorted sandy gravel berms, so would the bulk of the contaminants. Secondarily, the negligible leaching expected through the berm should

not cause any water quality problems. This was due in part to the large dilution factor of the tide flowing in and out of the berms. These ideas were

based on results from several US Army Corps of Engineers studies and our own

study at Terminal 105.

The previous studies that addressed leachate and contaminant mobility

were primarily those from the Corps of Engineers Dredged Material Research

Program. These studies (Brannon, Plumb, and Smith 1978; Chen et al. 1978;

Hoeppel, Myers, and Engler 1978; Mang et al. 1978; and Yu et al. 1978) indicated that with adequate control of the solids and the dilutions expected by

tidal mixing, there would be no significant impact and the project should meet

the appropriate water quality criteria.

68

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The Port of Seattle's previous study (Port of Seattle 1985) included a

preproject survey and five postproject surveys for priority pollutants in the

surrounding nearshore uplands disposal site of mildly contaminated dredged

material. This site at Terminal 105 was a pit excavated in the nearshore uplands about 400 ft from the Duwamish Waterway. Brakish ground water at the

site is tidally connected with the adjoining Duwamish Waterway through the

sandy soils. This study clearly showed the initial dewatering stage with a

small pulse of metals seen in the monitoring wells during the first few

months. The organic compounds of the priority pollutants generally showed no

movement except for phenols which were higher in the downgradient wells during

months one through seven. This is not entirely unexpected due to the mobility

of phenol and the mildly acid (pH 6.1) condition of the Terminal 105 ground

water. It was concluded from this field study that disposal in partially saturated, tidally connected uplands with a fresh ground-water head "upstream"

resulted in no loss of contaminants that would constitute a water quality

problem in the adjacent waterway.

Climate of Concern

More recent studies in Puget Sound have been focusing on the mass flux of %

contaminants and the "ultimate fate" of contaminants in disposal sites.

Among these was the Metro Toxicant Protreatment Planning Study (TPPS)

(Municipality of Metropolitan Seattle 1984) which looked at the fate and mass

flux of toxicants in Puget Sound as a system and, in particular, at the con-

*. tribution of municipal sewage effluent to the mass budgets. The TPPS brought

to the forefront the realization that, due to its glacier carved bathymetry

with a shallow inlet sill, Puget Sound has restricted flushing. The deeper

sediments become the final sink for much of the contaminant load. These findings led to concern about the carrying capacity of the Puget Sound sediments

and to the development of new contaminant criteria for the uncontained openwater disposal of dredged materials, and greater amounts of dredged material

requiring contained disposal.

The "ultimate fate" of materials placed in a contained disposal site was

also being reviewed by the Corps of Engineers' work (Javandel, Doughty, and

Tsang 1984) which focused on dredging as a means of disposal for the Commencement Bay Superfund site (sediments). This work was done as a part of a Superfund site remedial investigation requiring the consideration of "ultimate

fate." Based on more recent studies and approaches, the conclusion was that

dredged material kept in its original state, saturated and anaerobic, will

have maximum retention percent of contaminants. If unsaturated and oxv- -

genated, it will lose more contaminants. Contaminant losses are proportional

to water moving through the system.

Based on this more recent information, the regulatory agencies have required the Port to provide a more site-speciffi study of thc u:l Iimate fte of

the materials to be disposed of in the Terminal I fill. This was requested

in order for the agencies to assess the proposed constructisn, even though the

analysis of the sediments scheduled for disposal at the site ohowed that ontamination levels were well below hazardous waste classification (Vihle i).

,\s a result, the Port contracted for a modeling Study (hart -( rw .r .T J!( -

elates, Inc. , and IJRS Corporation 1985) to comb i ne data Iroy plk-.,i,,t , tnt. u,! 

7A* . .-... '-VV
TABLE 1. CONTAMINANT LEVELS IN TERMINAL 32 SEDIMENTS FOISPOSAL

~IN TERMINAL 91 SHORT FILL AND OPEN WATER*

Open-Water

Terminal 91 Disposal

Disposal Terminal 32

Terminal 32 Sediments Open Water Sediments ..

Failing 4-Mile ('#-Mile Rock) Passing 4-Mile .

Contaminant Rock Criteria Criteria Rock Criteria

Metals, ppm..

As 17.4 _t 3.3 19 3.7 -t 1.1 '.

Cd 5.0 t+ 2.9 0.9 0.68 _t 0.25 "''

Cu 119.0 -+ 48.7 115 17.6 t 7.2 ~

Pb 88. t 95.5 158 11.3 ± 15.5

%Hg 1.0 + 0.44 1.4 0.05 ± 0.06 "

Zn 435.9 ± 244 450 39.1 ± 11.3 -

Organics, ppb -',

PCBs 2,763 +-2,498 760 5.9 -+ 24.'-'

DDTs 72 + 74 9 N.D."'

High PAHs 8,485 -± 7,206 14,000 292 -± 547 .

Low PAHs 3,778 ± 3,620 855 236 _± 202

*Values are total sediment concentration, reported on a dry weight basis and

expressed as mean -+one standard deviation.

sediment chemistry, chemical theory, site permeability information, and

ground-water information. The goal was to produce site-specific recommendations for the design and monitoring of the proposed project.

Mode ling

'; This effort was conducted in three interdependent areas: site permeabil- .:

'itv, two-dimensional modeled flow rates, and final predictions of the concen-

-. trations of contaminants throughout the berm. "

a -

rPermeablaity

The permeaility study (Hart-'rowser and Asciates, Ic. 195) was aseda-g4i

on previou ground-water Crig wells, and ,tor Rixisting studies

, f propo sed bermn structural material . The in-plac' perrca ilitv, of tile

-2 .dredged material f illI was estimated from gri-iemeasqurements of the ma te - M ial. This pplid study (Figure 3) showed filled ei.:tinr piers with approximate ly 1 ( ft of sl1ightlIy more porons rerent lh,.,(r:i! ic i 1 ,-erlvin -r v i c

;.- ;0 1tv sainds, which are also( tile floor ,ot the slip. 7

Pb 8. 5. 15 1.3± 5.

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The ground water inland from the head end of the slip, though being 4 ft

above mean tide (+6.6), was found to be only minimally connected to the tides.

Approximately 2 percent of the measured tidal movement was reflected in the

ground water.

The permeability of the project berms is much lower than the existing

filled piers which are also much wider. The net result is that dewatering and

hydraulic tidal connection between the central fill and the open waterway is

expected to occur through the project berms. The permeability of the fill is

predicted to be orders of magnitude lower than the berms, and therefore controls water movement through the site.

Ground-Water Flow V

The hydraulic response of the system was modeled using the FPM Finite -

Element Model (Golder 1983) in a vertical two-dimensional slice configuration

with output (flow velocities and directions) used as input to the transport

model. It was run for both initial dewaLering and steady-state conditions In

a variety of situations representing possible construction alterations and

possible remedial actions.

The model used a two-dimensional cross section, north-south through the

berms and fill. The boundaries were the pond north herm face, the low permeability silt layer 20 to 30 ft below the silty sand of the existing waterway,

and the south berm waterway face. This cross section (Figure 4) was divided

into 214 elements defined by 240) nodes (corners). The output was tables (it

hydraulic heads for each node. D arcy flow vel(cities (magnit ude and direction)

for each element, and plots of head contours. The dewatering phase assumed

instantaneous construction; therefore, we used the 3(0 day- postconstruction as

an environmentally conservative highest level. The idealized 2-hr tidal component was simulated bv holding boundary condition water levels on the south

berm face at eight constant steps throughout the period. The head and duration ot each step were based on mean tidal values for Seattle.

The water f low modeling show- that the movement of water through this

fill is mainly dependent rn the groind-water head established in the upstream

pond and the permeability of the fill material. It also shows that artificiallv elevating the pond level to +1 during dewatering (to minimize flow

into the pond) has no signilicant benetit. However, after dewatering, artiIic al l lowering tile pond to mean tide level would P] imnate through flow

through the ti I and theref ore minimize Ctamlnant losses.

The cover till with I high permteahI I i tv equaI to that of tile berms, acts

as a top drain during the dewatt ring phase, and does not act as a pathway

liil()winw f,'nit icant cycling of pond tidal water o)r tidal cvcling through the

till ;is w. I ni ti al I y suspected. Manipulating the permeabil itv of the cover

f11, there!(,re, does not pr(ovide a significant environmental advantage. Infiltration through the aspihalt paving cap does not create a significant flow

thr~ughi the system as compared with tidal action or -dvective flow.

The h'draulic head contours (f igure 5) showed that most of the tidal

action occurs in tle herm and not in the till. The tidally induced velocities

- (Table ') are one to two orders of magnitude higher in the upper portion Of %

the berm.

.

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EL -39 . .Y (GRVELL.. SAND FILL) EL -39

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-- ____613 -,

Figure 4. Finite element mesh for berm-fill system

TABE 2. DARCY VELOCITIES AND MIXING AT THE BERM FACE (POND AT +9)

Flevation Tidal Velocit' Advective Velocity Mixing

It, msl m/day m/day Ratio %

+; to -3 5.7 10-1 3.8 10 - 3 150:1

- to -Is 1.5 10-1 6.7 10 - 225:1

- .4 t , - 1 3 IO 3.8 10 -- 350:1

ontaminant Transport

Fhe contaminant mass transported through the system was modeled using the

,,,tput ot the hydraul ic model as input to the LEACH 1-) (curvilinear) analvti-

(.I transport model (a modified form of OI)AST, lavandel, Doughty, and Tsang

. The contaminant mass transport model was run using the various hydrauitc model ottputs with a range of contaminant absorption/desorption constants

from d(k' = 0.1) to PCB (k' - 2900). This modeling showed that:

a. Implementation of the proposed Terminal 91 Short Fill as a dredged

material containment facility using the as-planned construction is

unlikely to produce concentrations of deleterious contaminants at the

waterway berm face which exceed chronic saltwater exposure criteria.

(admium and mercury concentrations within the south berm may begin to

exceed these standards at some time approximatelv 40 years in the

future. The maximum concentration should never be more than 10 times

above the criteria. Mixing at the berm face with dilution ratios of

more than 100 to I is likely to reduce these concentrations below

chronic saltwater exposure criteria.

b. Allowing the pond to remain at its natural level (estimated at elevation +9 ft) over the long term is unlikely to cause water flow to increase to the point that waterway berm face concentration levels

would exceed chronic saltwater exposure criteria. Concentrations

within the berm may reach these levels within 20 years if the dispersion in the berm is very low (0.1 m2 /day).

74

J. %,
Low Pond with High Permeability Top Fill 6

-.-. ~-..9.0

N 75 8.08.5

Tide= 10.0

(Rising)

180 Min

/6.7 6.0

Tide 5.15

* (Falling)

* 490 Min

7.0

* Tid=0.0 //$/~150 4.2.

~5.5

* (Low Low Water)4053

642 Min

* --- 1 2 Head Contour S

~ Flw DrecionHART-CROWSER & associates inc.

Figure 5. Hydraulic head contours during tidal cycle

75

e,
c. Contamination will be removed from the fill through two dominant

mechanisms: advective flow (caused both by dewatering of the dredged

material during consolidation and by flow from the pond during later

periods) and dispersion of contaminants (caused by tidal action).

Dewatering advection will dominate during the early stages (less than

1 year) while tidal dispersion will dominate after this period.

d. Cadmium and mercury are the contaminants most likely to reach concentration levels in the berm which could exceed chronic saltwater exposure criteria. Absorption is likely to retard the movement of most

organic contaminants.

e. Mixing at the waterway berm face is likely to cause more than a

100-to-i average dilution in comparison with concentrations in the

middle of the berm. The dilution of the berm is the result of mixing

of clean seawater with ground-water flow from the berm during each

tidal cycle. The bulk mixing ratio of more than 100 to 1 is based on

the ratio of the relative volumes moved by tidal action, to the volumes moved by advection from the elevated pond (+9 ft), and infiltrated precipitation. The actual concentration at any given time

during the tidal cycle is a function of dispersion. High dispersion

results in actual concentrations during most of the tidal cycle close

to the average produced by bulk mixing. Low dispersion will result

in actual concentration near seawater levels during most of the cycle

with short periods equal to in-berm concentrations.

f. Monitoring wells should be placed at the intertidal elevation in

order to first detect contaminant movement. Flow velocities are

highest and flow paths from the fill are shortest in this intertidal

zone. The first contaminants to discharge from the system are likely

to travel through this zone. Deeper wells should also be placed in

order to verify long-term discharge and to compute average discharge

rates and concentrations. Wells should be placed at the waterway

berm face to measure the actual concentration of discharges. Wells

in the middle of the berm area are also recommended to monitor inberm concentrations.

. Sensitivity analyses indicate that the system is sensitive to variations in the value of: dispersivity, hydraulic conductivity of the

fill, and pond elevation. Sensitivities were such that:

(1) A one-order-of-magnitude variation in dispersion could cause a

variation of one order of magnitude in concentration at certain

distances and times.

(2) A one-order-of-magnitude variation in dredged material fill hydraulic conductivity could cause a variation in flow velocity of

one order of magnitude within the berm.

(3) A 3-ft increase in pond height could cause a fivefold increase

in berm velocity through the berm.

h. The system was not sensitive to hydraulic conductivity of the berm,

rate of infiltrated precipitation through the asphalt-covered top,

76

%
storativity of the dewatered fill, or specific storage of the whole

system. An order-of-magnitude variation in these parameters (except

specific storage) caused less than a 20 percent variation in berm

flow velocities. A 50 percent variation in specific storage caused

no measurable variation in berm flow velocity.

In summary, the modeling shows that the performance of the project is expected to meet the water quality criteria and the general goals of the containment. It shows that the probability of excessive contaminant loss is

small and that even if it occurs, the impact is minimal on the specific site.

The minimal impact conclusion is due to the low level, small quantity aspect

of the leachate, and existing site contamination. The sediments of the existing site are as contaminated as those requiring containment in the fill. The

site receives a large contaminant from several major storm drains and combined

sewer overflows emptying into the immediate and nearby arch.

On the strength of these conclusions, the Port has been allowed to pro- .- ,

ceed, provided that an acceptable monitoring and remedial actions plan could

be prepared.

Criteria, Threshold.,

Monitoring, and Remedial Action Plan

The following is a detailed summary of the plan (Port of Seattle 1985)

designed by the Port in cooperation with the Washington Department of Ecology

and the other regulatory and resource agencies. The goals of this plan, and

the subsequent monitoring program, are:

a. Establish the basic criteria against which performance of the disposal site will be measured.

b. Set up the monitoring program to measure the performance and follow

the movement of contaminants at the site.

C. Establish threshold levels for initiation of remedial actions.

d. Set up the remedial actions that will be undertaken if the system

does not meet the criteria and should prove to be a long-term water

quality problem.

e. Propose research and modeling verification that will make these results more applicable to other dredged material disposal projects.

f. Prepare a monitoring plan to ensure the protection of local water

quality during the filling operation.

The containment performance monitoring program is based upon accepted

marine water quality criteria and consists of berm well samples and water col- 2 umn samples that will be or are in the threshold/remedial action phase. Additional well and pond samples will be collected to provide research information on movement of contaminants in the confined disposal site. All samples

will be analyzed for heavy metals and some for full priority pollutants. .

77 .'. .'

% %

%~~~ LM 1
There will also be a monitoring program for the pond and a water quality mon- %

itoring program for the disposal operation. These are standard water quality

type programs and will not be elaborated on in this paper.

The thresholds for remedial action apply only to the wells in south berm,

Pier 90 and Pier 91. The dilution factors for calculating the threshold levels from the well data will be derived from the field sampling of the corresponding sets of berm face wells, and vertical berm wells located at the center of the south berm. Exceeding a threshold value will initiate notification

of the agencies and a series of confirming samples. Action decisions will be

based on these sample sets. -'

The sampling frequency will be high during the first 6 months to document

the dewatering stage and to establish dilution factors. The frequency will

then be reduced. The monitoring program will be reviewed annually with the

objective of reducing unproductive sampling. The long-term monitoring will be

conducted quarterly and then semiannually. It will last for a total of

4 years after capping. At this point, the entire program will be reviewed and

any future work decided upon.

The data will be reported to Washington Department of Ecology (WDOE), the

Corps of Engineers (CE), and the Environmental Protection Agency (EPA) after

each sample series. Water quality data from the disposal operation will be

reported within 48 hr. Any decision regarding the performance o! the fill

containment and the need to institute remedial action will include WDOE, EPA,

CE, and the Port of Seattle.

The main focus of the remedial action is to repair the site if a chronic

water quality problem should exist. It is understood that the extensive con- 2e

struction necessary for the more extreme remedial actions and the time delays

in confirming any real problem make it unrealistic to consider it applicable

to the initial dewatering plan.

After the first year of monitoring and research, the data from the field

studies will be used to update and reevaluate the long-term projections from

computer modeling.

Criteria %

The criteria used to judge the acceptable operation of the confined disp(sal site will be the EPA marine water quality criteria applied at the south

berm face or side pier faces. The chronic criteria will be applied at the

berm or pier face "discharge area." Where there are no EPA-accepted criteria,

"background" seawater and 10 times background seawater will be used in a twotier criteria. Exceeding l) times (1OX) background will initiate the same

response as the EPA chronic criteria. Above background will initiate notitication of WDOE , EPA, and (:C and meetings with the Port and these regulatory

agencies to determine the need for contirming samples, the impact o1 the compound detected, and the appropriate remedial actions, if any. These discus-

,ions will rely heavily on the EPA list of "Lowest Reported Toxic Concentrations" for priority pollutants. Any decision to call for remedial action will

be based on a confirmed water qualitv problem. Though the WIM)OE, EPA, and CE

'I 78 %

% * "*%"
have independent authority under the Clean Water Act that could apply to this

situation, any decision to require remedial action will be made by consultation among these regulatory agencies.

Action Thresholds

The action threshold levels are those levels in the monitoring wells fop%

which would indicate a high probability of exceeding chronic saltwater criteria at the berm faces. This would indicate a failure of the disposal site ' -

to adequately contain the contaminants of concern, and could justify initiating remedial action. Initially, data from samples taken in the berm face

wells will be compared against the established criteria. If criteria are

exceeded, discussions between the Port of Seattle and the WDOE will be initiated. These discussions will first establish an appropriate dilution ratio. - -

Secondly, there will be an analysis of the contaminant at the dilution ratio

established to determine if there is an adverse impact to the aquatic

environment.

The site-specific information used to establish the dilution factors between the berm face, the berm face wells, and the vertical berm wells will in- "IZ

clude both the modeling information and the field sampling data from the south

berm. When finalized, these factors will be applied to all the south, east,

and west berm pier vertical wells.

Decisions to begin remedial action to reduce the mobility of contaminants

will be made based on the wells installed in the south, east, and west berms,

and the seawater sample stations. Samples exceeding the threshold levels

will initiate a more intense sampling sequence of three additional sample

sets, taken at the affected sites every other week for 5 weeks and analyzed '.

for the contaminants of concern. If the mean of these four samples is statistically greater than the threshold level, then discussions of the appropriate

remedial action will be initiated with WDOE, EPA, and CE.

The exception to this sequence will be during the initial 6 months

dewatering/consolidation phase. The dewatering is an extension of the construction phase and therefore is an accepted short-term impact (6-month) that

may affect water quality at the berm face, but not beyond the dilution zone in

the center waterway slip. During this period a problem with the disposal oper-

;ition would be indicated by exceeding acute water quality criteria at the berm

face or by exceeding chronic water quality criteria in the center slip beyond

the dilution zone (100 yards south of the south crest of the south berm). . .

Monitoring Program

The monitoring program consists of ten well sites (Figure 6), three of

which are three level well nests, and six water stations.

The frequency of sampling (Table 3) will vary during initial construction, the early consolidation phase, and the long-term monitoring phase. A

suite of six metals (Cd, Hg, As, Zn, Pb, and Cu) and total organic carbon

(TOC) will be sampled on a regular basis. There will also be several sampling

series for the compounds on the priority pollutant list, an hourly sampling

across a tidal cycle, and other research sampling.

79

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* The construction period sampling will consist of two samples from the

* upstream and east and west pier wells. The other berm wells will be drilled

* as soon as possible and sampled twice during the fill operation along with the

east and west pier wells.

Sampling will begin when the south berm is in place with vertical well

nest and berm face well nest installed and in operation. This will be about

the same time the fill is capped. This standard sampling will begin withN,

monthly sampling for 6 months, then change to quarterly for the next

1-1/2 years, and finally to semiannually for the last 2 years. At this time

there will be a major program review. If there are no significant water quality problems, the stations and analyses will be greatly reduced based on the

knowledge gained.

Monitoring samples are to be taken during the last half of an outgoing

tide. The water station samples will be taken on the same day, preferably on

the same tide. All samples will be processed for the dissolved contaminants

and not particulates. Standard field observations of time, tide well water,

height, etc., will be taken at all stations. Standard analysis will be by the

* EPA-approved methods and to the standard minimum detection limits for

seawater. 1N

Remedial Actions

The following remedial actions represent those techniques found to be

feasible in a site-specific engineering study of the possible options. Remedial actions will be implemented incrementally with follow-up testing to

determine the effectiveness of each increment. The appropriate initial increment will be chosen by mutual agreement between; WDOE, EPA, and CE in discussions with the Port. The actions include:

a. Maintain the pond water at mean tidal level (+6.6).

b. Pump interstitial water out of the fill and discharge to a METRO

treatment plant (an interim measure). This would minimize water flow

seaward through the south berm.

c. Ensure in-place chemical stabilization. This is a new technique, and

* would be used only if available information shows it to be acceptable

for a specific contaminant.

d. Install a slurry wall in the north and south berms.

e. Install a slurry wall in the east and west piers.

f. Remove the contaminated dredged material from between the berms.

CONCLUS IONS...

The Terminal 91 Short Fill project is providing a demonstration that

* nearshore unlined contained disposal of mildly contaminated dredged material

is a viable option, even with increased concern over contaminant mobility.

Because of the factors affecting mobility, a site-specific analysis must be

* performed.

82

.. ..Z . . . . . . 9
* - - - - ~N~L%.- " ,,

__|

The approach taken by the Port is a reasonable route to obtaining the

permits to begin construction when generic information indicates, but does not

give specific assurance, that the project will meet newer, more advanced water

quality concerns. Using computer modeling in a site-specific preproject

analysis in conjunction with monitoring and agreed-upon remedial action steps GNP.

gives the greatest assurances that containment goals will be met and the envi---1. 0

ronment protected. This is an expensive approach and only cost-effective e

where the site-specific analysis shows a high probability that the water qual- f/f

ity criteria will be met. po

REFERENCES

Brannon, J. M., Plumb, R. H., Jr., and Smith, I. 1978. "Long-Term Release of

Contaminants from Dredged Material," Technical Report D-78-49, US Army Engineer Waterways Experiment Station, Vicksburg, Miss.

Chen, K. Y., Eichenbeger, B., Mang, J. L., and Hoeppel, R. E. 1978. "Confined Disposal Area Effluent and Leachate Control (Laboratory and Field Investigations)," Technical Report DS-78-7, US Army Engineer Waterways Experiment

Station, Vicksburg, Miss.

Goler, 1983. Groundwater Computer Package.

Hart-Crowser and Associates, Inc. 1985. "Modeling Assistance, Terminal 91,

Seattle, Washington," Hart-Crowser Report J-1029-03.

Hart-Crowser and Associates, Inc., and URS Corporation, 1985. "Hydraulic and

Contaminant Modeling, Terminal 91, Seattle, Washington," Hart-Crowser Report

J-1039-05.

Hoeppel, R. E., Myers, T. E., and Engler, R. M. 1978. "Physical and Chemical

Characterization of Dredged Material Influents and Effluents in Confined Land ..

Disposal Areas," Technical Report D-78-24, US Army Engineer Waterways Experiment Station, Vicksburg, Miss.

Javandel, I., Doughty, C., and Tsang, Chin-Fu. 1984. "Groundwater Transport:

Handbook of Mathematical Models," Water Resources Monograph 10, American Geophysical Union, Washington, D. C.

Mang, J. L., Lu, J. C. D., Lofy, R. J., and Stearns, R. P. 1978. "A Study of

Leachate from Dredged Material in Upland Areas and/or in Productive Uses,"

Technical Report D-78-20, US Army Engineer Waterways Experiment Station,

Vicksburg, Miss.

Municipality of Metropolitan Seattle (METRO). 1984. "Presence, Distribution,

and Fate of Toxicants in Puget Sound and Lake Washington," Toxicant Pretreatment Planning Study, Technical Report C1, Seattle, Wash.

Phillips, K. E., Malek, J. R., and Hamner, B. W. 1985. "Evaluation of Alternative Dredging Methods and Equipment, Disposal Methods and Sites, and Site

Control and Treatment Practices for Contaminated Sediments," US Army Engineer

District, Seattle, prepared for Washington State Department of Ecology,

Seattle, Wash.

83 "

%_r-
Port of Seattle. 1985. "Monitoring of Cround Water Surrounding an Upland

Disposal of PCB-Contaminated Dredged Material," Planning and Research Department, Seattle, Wash.

Port of Seattle. 1985. "Criteria, Thresholds, Monitoring and Remedial Actions Plan," Environmental Planning, Engineering Department, Seattle, Wash.

Yu, K. Y., Chen, K. Y., Morrison, R. D., and Mang, I. L. 1978. "I'hvsicaI and

Chemical Characterization of Dredged Material Sediments and Leachate in Confined Land Dispsal Areas," Technical Report D-78-43, U'S Army Fngineer

Waterways Experiment Station, Vicksburg, Miss.

-.

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U,.'

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84 

N
.

'p

TEST RFSJTLTS OF SF1) N11V RFMO%',A I'.ISE BAY

Tsutomu NXikano

Chier, Sea board Improvement Di, isien, The 5th District

Port Construction Bureau, Ministry of Transport

Makoto Natori

Executive Director, lapan Bottom

Sediments Management Association

Yutaka Taguchi

Director, Manager of Technical Division,

JTapan Bottom Sediments Management Association 5,.

ABSTRACT

The 5th District Port Construction Bureau, Ministry of 'raiispor1, lidS been conducting studies to

obtain a feasible method for sediment removal in Ise

Bay. These studies were conducted in Mikawa Bay to

ascertain the effect and method of sediment removal

since 1980. These studies were conducted prior to

carrying out the sediment removal in Ise Bay, one of

the major works for improvement of the ocean

environment.

This paper summarizes a study of the effects of

sediment removal, in terms of the amount of released

organics and nutrients, and recovery of biotas and

other findings in dredging tests performed in 1980 in

highly contaminated sediments.

INTRODUCTION

Mikawa Bay, a part of Ise Bay, is backed by the City of Nagoya and is

situated at the center of the Japanese Archipelago. Mikawa Bay is a closed

inland bay bounded by the Chita Peninsula and the Atsumi Peninsula (Figure 1).

The 600-sq-km Mikawa Bay is shallow with an average depth of 9.2 m and a I

very narrow (about 10 km) mouth. These conditions de nct favor the interchange of seawater, but do favor eutrophication.

First class rivers such as the Yahagi Rivet and the Toyo River flow into

the sea. The inflow loads from these rivers to the whole area of the Mikawa

Bay included approximately 69 tons/day of chemical oxygen demand (COD),

35 tons/day of total nitrogen (T-N), and 3.0 tons/day of total phosphorus

(T-P) in 1979. The Aichi Prefectural Government established the total amount

regulation program with regard to COD in Ise Bay and Mikawa Bay in 1980, and

has been implementing the program to reduce the inflow loads.

85
>D-R196 119 MANAGEMENT OF BOTTOM SEDIMENTS CONTAINING TOXIC /

1L SUBSTANCES: PROCEEDINGS .. (U) ARMY ENGINEER HTER AYS ' EXPERIMENT STATION VICKSBURG MS ENVIR.. T R PATIN

RSIIDAPR 87 F/G 24/3 M
-~ W ~ h * ~ ~ ~-U9W b .~ hIH ~. .--. -- .-

-..,

I

'NI'

lull-,-- liii- I

'ml" :L:E2

.°.. m
It" I go ti

1- igure 1. 1 (;1t i on of M ikawa Bay

Hoewever. i, _v~en in 1-igute .. in spite, ot the program to reduce COD),A

'-e.iw.tt vr p11- 11t, ha - no t i mproved mutch s Ince thte env ironmen talI qua I i tv

~t in!a rd 1 enit i nta I Iv e \,-eeded.

*The ir eq ient otf red t i de I s shown i n Figuire 3, and t he f I she rv i s he i ng

*I#I .r v-tf hAdlv. figure 4 indicates that organic sediments with a concentraiOn1 (1 over 40 mg ~:..of COO) is accumulating at the central part of Mikawa

ina\ Since sedimt'nt OD1 at teers the occurrence of red tides, sediment removal

Was On,, I de red.

'leow cond it ions i n M ikawa Bay are clIoc-kwise and steady In the Inner part

,) the bav and counterclockwise and steady in the central part of the bay. At

the central part of these two steadv flows, highly concentrated orgaric sedi-

* Rment accumulates and is coincident with the retention area.

In order to improve water quality in Mikawa Bay where eutrophication has

* aidvanced considerably, it is necessary to reduce inflow loads and to minimize

nutrient release. To do this, The 5th District Port Construction Bureau, Ministrv ot Transportation, is presently examining sediment removal projects.

5%

C2-------- -- - - - - Environmetal standard

.0 )~972 73 74 7576 77 78 79 80 ) 882 83 84

Figure 2. Annual variation of COD)

86

le - V %ij
, .... I

...'*ON

516 % ~*

Tota' number I3C Totai numrer It

80 73 233

4024' . se ,% 302 ._ 1 5 ,,

ura Ba. 2 0 Kinuura Bay " 5

1973 '78 80 62 1973 '78 180 '82

,. Variations of red tide h. Numbers of days of

occurrence occurrence

Figure 1. Red tide frequency of occurrence and numbers of days of

occurrence in Ise and Mikawa Bays (Note: Total number

in 1979, 1981, 1982, and 1983 includes one case that

occurred in the open sea of Atsumi)

Nacoya c'tv I

SSediment COC 20 mq~

E2 Sediment COD 30 m, gsizuka C t i

4atsijsaka c"tY "M".--a

1-20

yI

Figure 4. COD distribution of sediment in Ise Bay

One of the projects involved sediment removal at the center of Mikawa Bay,

where substantial organic sediment accumulates. A general description of this

part of the study is given below.

SYSTEM OF STUDY

The system of study is shown in Figure 5. 'W

87

,% w ". ". ". ". % " " % ", . ,. ..- . . . . . . - , %,. ..- . , ,- - . . -, . , . -, Z *,i N ** , ,, , * -,, .7 .-..-.. , . - t, - ,..-;.. ,,..,... - .-.7,-,..- '-7 .:
%,.

r

* TEST SITES

N*...... ... . ......

TaFigure of 6. stady At "k'wy•

Higashi-hazu dredge in June Harbor in Mikawa Bay, sediment removal was performed by pump-type"" 1980. Sediment removal was conducted in the area extending

00 m south and north, 100 m east and west, and with a depth of 0.6 m. The .

outer circumference was dredged in a deep ditch in order to prevent settling'.

back of sediment from surroundings. Plane and cross-sectional views are shown i.

in F ig u r e 7 . . _. See Appendix A for details of tTe study.

Sl%

.,3 - 'Dredged Area.,

"I ,// / / ,.

) / .. ... " - "

50. , 1c 00,0. - " i,/ [- 13.6 Trench

,, - . . *-7. ,-q Si...

- - 2Cm, 2 k" - 1.2. ic,,

0 'S

Figure 7. Plane and

Figure 6. Location of test sites cross-sectional of dredged area view

88

TEST SITE%
Fol OW-PP STIUiP O F SEIMIFNT-REM(OVIN(; EFYE(C:'I

The study conducted in 1980 and 1981 is discussed below. Some Items of

the study have been continued.

Purpose of Study

The study was performed to determine the elfects of sediment removal on .0 %

the conditions of organic and nutrient release from sediment, oxvgen demand,

and recovery of biot,,.

Sampling Stations

Seven sampling stations were set up inside and outside the dredged area

(Figure 8); stations No. I to No. 3 are located within the dredged area, and

No. 4 to No. 7 are outside the area of dredging.

No. 3 NO.

,,,

Figure M. Sampling stations ...... , .. .

L _ __ , O.5NO'5

Contents of Study

A list of the items studied is shown in Table 1.

Results of Study

Results of the study are itemized below:

a. Conditions of flow.

(1) Tidal current. The tidal current of the upper and lower water

layers runs toward the inner part of the bay during rising tide

and toward the mouth of bay during ebb tide.

(2) Steady flow. Steady flow (daily average flow) varies widely

with flow direction and velocity. The maximum velocity In the

upper water layer reached 20 cm/sec during both examinations and

can temporarily run faster than the tidal current.

89

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b. Sediment (Figure 9).

(1) Organic pollutant index. The examination (in June) prior to the

test indicated that the values of sediment between the outside

and inside area were similar; however, after sediment removal a "

reduced amount of organics and nutrients inside the area was %J1

noted. Subsequently, the sediment indicated almost -onstant "

values until the third study in December after the test. The

fourth study in February indicated a slight increase, piubably a

seasonal variation, he difference between the outside and

inside area was ma*- .

(2) Oxidation - reducti, n potential of sediment. The sediments outside the area were highly reduced when compared with the dredged

inside area. Inside the area the oxidation reduction potential

(ORP) is reduced during periods from the first study in July to

the fourth study, and a tendency of weak reduction of sediment

is shown. However, seasonal variations of T-S and sulfatereducing bacteria are small.

(3) Physical properties. The sediment consisted of fine silt and

clay, but little difference is seen in unit volume weight and

moisture content ratio.

c. Benthos (Figure 10).

(1) Seasonal variations. Macrobenthos showed a noticeable reduction

in wet weight, number of species, and number of individuals in

the second study in September, compared with the study in June

before the test and the first study in July. Theora fy-agiZc.'.

belonging to Mollusca, predominant up to that time, disappeared

and AneiptrosylZic hanaokai and Prionokio cirrifera of Polychaeta now predominate. However, an increase in numbers of ,%'

species and number of individuals occurred in the third study in

December and the fourth study in February. This may indicate a

recovery of the biota.

(2) Difference between the outside area and the dredged inside area.

The first study in July after the test showed a noticeable reduction in microbenthos in the dredged inside area. This may he

a result of the influence of testing. However, the second study

In September, the third study in December, and the fourth study

in February after the test showed a slight increase In the microbenthos of the inside area compared with the outside.

d. Pore water concentrations of P, N, and COD. --

(1) Vertical distribution (Figure 11). Generally, the concentrations in the pore water were lower in the dredged area.

Seasonal variations tend to be high in September and low in

December; however, N and P in the area of sediment removal have

been depressed since July.

91

- . -.,-. 
1'0

2 2

2 6 2 6

1 J8: 1980c 81 82 -

Is

* 0

19J828 82

09 Tj 8 68

-iV

F ~ it__ i -_ _ '"1
418.

44%*

dX',

419~

41 %

4 4?

e 0-- 0~ l

C CD

4 0 D0

')~4 -C) (N 0A'

93-

%C
".%

COO (-I* ri*m r-O % J.* ,

O 0 1 0 2, 2 , 40 B 1 . 0 2

8 10 100 %

201 20'

30 30' 30. I

0 0

1C 10

- ob \_\_- ___-_.

co---__ ---------- '- 9 , 0Q 2' 4. ,:"

"\I \\'"" °

£2' 0 20k

3 . 30 30.

C 20 30 4 8 B '2 16 1 2 3

0r

j 1"°C' ] o ""

10;

" 2ok ,\o, ]20t,/ ,

3 C, 30'i ,

Figure It. Vertical distribution of pore water

(2) Decomposition rate of organics in sediment (Figure I2). The

pore water daily variation of organic concentrations was studied

for 3(0 days by incubating the sediment (0-10 cm) with water

temperature of the testing stations. The decomposition rate ol

organics inside the area ot removal was slower than that outside

the area in the second to fourth studies. This may indicate

that hard-to-decompose organic,; are prevalent in those c;tudv

areas.

V-. Re lease test (Figure 1 ). Release test equipment was installed Inside and ,ntside the dredged area to determine variations in release

I lux. Both N and P showed higher valte S iti the otitside area iT1 the

first studv In .IuIv and the third study in Jiecember. lhe second

study in September indicated a vecv low reiease I lux, and considerable differences between two areas were not seen.

%.

i. % . ,* f d .. .'- 2-"- ". ' *'-'* ." "-*.*.%'-' ; . -" . .. .. . % .. ,% .'- .. .. .*.. .. "• ." "
Decomposition rate of COD

0 0 200 4W0 mr~a

I. st

Figure 1?1. Sediment decomposition rate 2nd

~ 3rd S..

St. 7

~'4th

T-N release flux T-P release flux

0 30y IQ3 ~

2nd a

T 0- elaefu

T1release flux ~rlaefu

0 10 30 50 N/Mday 10 30 50md, *

I s:

2n~ 2nd

3 -3rt

Blro

S*a.

f. 1) isso Ived o~xvp en demand tes t (Figure 14) . The dissolved oxvgen (D))

demand o)f seawater in the inside and outside area was determ.-ied )n -

the seabed. Resnl ts obtained from each study showed the value in the

inside irea to he lower than the outside area.

g.New deposition. A sampler was installed in the wattr to determine

deo~t onratoe qince the tests were conducted. The I irst stud-, it)

July r~o-.uted in 0.2 to H.3 cm/year at a laver rr, above the- ceahed.

ec1tsof the third study in December showed the vultuO to he Olne

order greater than that of the f irst study. This re.su] ted irom tht,

nt luence ot scatter ing.

9 5

.7-
i .- .

00 demand rate

Q%"

0 ,G UI ) rncz./m: a -

IS: -

Figure 14. DO demand rate at stations

No. I and No. 7

CONCLUS IONS

In order to understand the effects of sediment removal on ocean environmental improvement, a dredging project was conducted in Mikawa Bay, along with

a follow-up study on the effects of the removal. Conclusions ascertained one

year after the test was completed are as follows:

a. The organic and nutrient content in sediment was reduced.

I. The pore water index was low in the dredged inside area.

C. Decomposition rate ot organics in sediment tended t(, he higher In the'"-

outside arei.

d. f T bt, nths, the numbers irdividu:1l I , number >pe je, and wt. t

weight Ir:( reased cn,, iderahlv iri'. ide the area ;a ,mpajrt-d with, the

,ut side area.

Hf wever, tie result -,o! t longer tvrr , tudv fh,,w that t It- c !, 0i. - -"

twev r, t!iv ,ue t - (!t- area and t: e d redwed ii-. ide area, i- , r ; 7in-: , n' , :it

Tl i,itered init-,, . r lye !, . ",ng-ter re -Va e. trn,- e . t. .,. ta r "'" 

it ... i, ot '-,- i ent ,( iurroiund ir!. ires,, .

rn,- t' t A .. ',-V, t tii',, it Wit- I- Irt lit . : t 7t,- tr" ,

We .eti. t1 ' ,. r; re !t 'er , ,-e ' .. nt I r- .. . , 

: e ,t t ht, r,-r Mttb-i * r t'ie i fwl. eflVl,!!. I. I . tn; . a , -

% . % % ...

J e ... ... .. . .. .. * . . . .-.. . -... : . .. 2- - . - a -----
- - - S - - -. a

-p.

-a

'p

p

.1 p.

p

p

-a

-a

4

4

4

4

-p.

4

4-.

4-.

a.

4-

'p APPENDIX A: STUDY DETAILS

4-.

-a

-p.

4.

-%

- ~. V V.. -. V C :.2. . . . . %\'.~
V)V

cm,

00 4 . %

U,

0. - -.V

44

4

S.-

CL w'

co,

to

C7)

-,A" %,

U- "7-"

S--

-. .

-.' -

"" - ",, . -"-" . ..o" " " .*". .' * . = .¢ . . . "* , .. . . - ., . . • " - . .". " . ." . , .. . - .- • "- -

.., , , _ ,, - ,. . " "- ,, ,, . ., ." . . ," . . . i" " " " " " " " " " "% "

N." "* "' ".'' -" . " -
4..-.

TABLE Al. ANALYTICAL RESULTS OF SEDIMENT

Items Analvtical Results Criteria

Cyanides (mg/i) 0.1 (mg/) Less than 1 (mg/)

Cadmium (mg/i) 0.005 (mg/i) Less than 0.1 (mg/'r)

Arsenic (mg/) 0.02 (mg/i) Less than 0.5 (mg/i) e_

Alkaly mercury (mg/i) Should not be Should not be detected

detected -

Total mercury (mg/i) 0.0005 (mg/) Less than 0.005 (mg/i)

Lead (mg/) 0.05 (mg/i) Less than I (mg/,)

Sexivalent (mg/i) 0.02 (mg/i) Less than 0.5 (mg/t)

chromium

Phosphorus (mg/i) 0.1 (mg/i) Less than I (mg/0)

PCB (mg/k') 0.0005 (mg/k) Less than 0.003 (mg/U)

Construction period and volume of dredged soil

Construction: June 5 - July 31, 1980

Volume of soil: 11,990 M1 (Area 10,000 i 2 )

e Main capacity ot dredge

IPepth of dredging: 3.5 - 20.0 m

* i tance for tr.tnsporttion: hiarp' loaiding - m, "

re'dging ip,wcitv: I 1) to 4() m' 1,r

I..'.

4..

* - . - . . .- . . - - . . . . . ;,., - . - . ..* -

%.%'. .

•~W e ,-]
Sludge collector

Sludge collector driving A

unit: DC 110 kW

Bearing revolution: 3 - 15 rpm

Open/shut shutter: Oil pressure, remote control type

Ladder control: Oil pressure, remote control type

Gas purge: Ejector

Dredge pump

Ladder Pump In-Ship Pump

Type: Volute

Rated power: 150 PS

Pumping capacity: 800- 2,000 m3 /h 800 - 2,000 ms/h

Head: 10 - 20 m 20 - 50 m

Revolution: 490 - 700 rpm 200 - 310 rpm

Motor: AC 110 kW D 2,000 PS

Pipe size: Suction/delivery 400 im/400 m

Check valve: Oil pressure type

* Operation monitoring '.

TV monitoring system: Submerged TV camera,

Monitoring video unit,

Lighting unit

TurbiditY monitoring system: Analog meter with recorder

Depth monitoring system: Analog meter with recorder

S(Composition of ships

Dredge D 2,25( PS I vessel

Wincier 15 tons I vessel

:7,

23 m - 11 m 2.25 m I vessel

rransport Ion 2,'00 m 3 1 vessel

Pi1i r 1) 2,600 PS 1 vessel

100
(1) With CapsI

ValIve

MMl

Seawater

exchanged

befor e test

-77--,

(2) With Caps (blank)

Seawa ter

excha nge~i

before test

Partition

plate to

prevent release from

r seliment

(3) Without Caps

During Test

* 1~Tai

Figure A2. Release test pipes C

%0
% "O,

.

-10mm

20mm 1t layer

Cover

2nd layer

2Lcylindrical bottle ndlae

-~ 3rd ayer a.'. LI 'aa

~~St la4hy lye

Enlarged drawing 5th layer I

a% .. '

o. 25,m///! Sea ///

a. Upper and intermediate layer (1 - 2 layer) .

,€a..

1000 B 7 5 4 3 2 71-'

ffn 8 rZF4-4Ar :D *,,

2 Z cylindrical oottle

0

- I|-- -

awn

b. Lower laver (3- 5 layer)

Figure A3. Installation of newly precipitating

matter sampler

F r W" % %

l~l. . - '

,.-. _, .,L,'LW'LV._,CW.'%,r -. ,.,. ,.- % .% . ",, .%," ., ... -. , ,r., .. .. ,.-. . .. , • ,. , "". ". ".,'..'-,.' , •. •• ",, ". " ' ."'- "" ,,
EVALUATION OF DREDGING AS A REMEDIAL TECHNOLOGY

FOR THE COMMENCEMENT BAY SUPERFUND SITE

i.

Keith E. Phillips, John F. Malek %

US Army Corps of Engineers

Seattle District

PO Box C-3755

Seattle, Washington 98124-2255

ABSTRACT

Recent studies in Puget Sound have demonstrated a .-

link between elevated concentrations of chemicals in

bottom sediments and serious diseases (e.g., liver carcinomas) in bottom-dwelling fish. These and other

studies have led to intensified efforts to identify

contaminant sources and to clean up problem sediments.

Remedial action at the Commencement Bay Nearshore/

Tideflats Superfund Site, in the State of Washington,

USA, is expected to include dredging and disposal of

contaminated sediments from the bay's industrialized

waterways. In addition, intensive navigation activities often require handling contaminated sediments.

In response to this close interaction between Superfund cleanup investigations and navigation needs, the

Corps of Engineers assicted the State of Washington by

conducting an analysis of alternative dredging methods

and equipment, disposal methods and sites, and site

control and treatment practices for contaminated sediments derived from the bay.

This paper reviews some of the conclusions of the

alternatives study regarding preferred dredging and

disposal practices for sediment contamination found in

Commencement Bav. Factors influencing contaminant mobility and an example application of chemical partitioning coefficients to a screening assessment of contaminated sediments are discussed. Key considerations

in selecting appropriate equipment and methods, and

the preferred methods for various classes ol contaminants. are presented. Subsequent work by the Corps to

develop dec isionmaking guidawce for dredged material

management is briefly reviewed.

The ('onmencement hay Superfund evaluations served

to highlight a numbet of issues related to navigation

project planning, acceptable dispo;alI practice,, andlong-term management of contaminated sediments. I he

int luence and consequences of these issues to dredged

material man.agement in I'et Sound ;ire (list(s1 ed.

• "4.

.[ .'p
INTRODUCTION ". d

In the late 1970s, Puget Sound (Figure 1) was generally perceived as an

ecologically rich and diverse marine water body nestled between two snowcapped mountain ranges to the west and east. The region's abundant precipi- _*

tation and snowmelt swelled the numerous rivers that were the source and destination of the region's other famous resource, salmon. "Water quality"

problems of the 1950s were improving. "Pollution" in Puget Sound referred to

the aroma emanating from the occasional pulp mill and smelter stacks of the

Northwest.

This perception abruptly shifted with the identification of chemical S.

pollutants concentrated in sediments and biota at numerous locations in the

Sound. While highest concentrations of these chemicals have been identified

near major population and industrial centers, contaminants also have been

identified in marine sediments and organisms in areas previously thought to be

clean. Many of the chemicals accumulated in bottom-dwelling fish, and high

levels of certain toxic chemicals in the urban bays were linked to serious

diseases (e.g., liver carcinomas) of English sole (Parophrys vetuZus) and

other demersal fish species (Malins et al. 1984). These discoveries increasingly focused agency and public attention on the health of the Sound, raising

questions regarding past practices and decisionmaking criteria.

In October 1981, the US Environmental Protection Agency (EPA) identified

the Commencement Bay area of Tacoma, Washington, as one of the top priority

sites on the national list of "Superfund" (Comprehensive Environmental Response, Compensation and Liability Act of 1980) hazardous waste sites. Site ""

priority was based on widespread contamination in the soils, sediments, and

biota of the bay resulting from airborne emissions of arsenic and cadmium from

a local copper smelter, leaching of toxic metals from the large quantities of

smelter slag deposited along the marine shoreline at the plant and as fill in

the intertidal areas of the bay, and organic contaminants discharged by historical and current Industrial activities (including four chemical manufacturing plants, two petroleum refineries, a pulp m4ll, a municipal treatment

plant, and numerous waste disposal sites). Over 900 individual organic compounds have been detected In the bay sediments (Malins et al. 1984).

Remedial investigations of the site, performed with the State of Wash- -

Ington Department of Ecology (WDOE) as lead agency, focused on defining the

extent of contamination in water, sediments, and biota; determining the contamination threat to health, welfare, and the environment; and identifyingr.s

contamination sources and feasible remedial actions.

A major output of the remedial investigations has been the identification

,:I i "problem" sediment that is sufficiently hazardous in place to warrant

Superfund remedial action. A "problem" sediment was defined by all action

thres,,Id level that considers variables such as degree of sediment chemical -

ol,,t; mlnat ion, sediment toxicitv, contaminant bioaccumtlation, fish pathology,

And benthic macroinvertebrate community structure. Areas exceeding predetermined action levels were evaluated in terms of appropriate remedial response: %

(ai) outaminant source control only, (h) sediment removal/containment only,

I source control and ,;ediment removal/containment, and (d) areas that are

e.xpected to recover to levels helow threshold by natural processes. Dredging "'.

Iq a 111,-'' remedial rethod f(r, problem groups (b) and (c), In addit ion,

.01
PUGET SOUND, WASHINGTON

-----------

----------

EVERETT.

HOOD CANA

SEATTLE.

BREMERTON

('(W iI't V 'v( -

HATACOAAA

OtYMSI..
intensive navigation in the Bay's inutra waterways routinely requiresre

moval of contaminated sediments that may fall below (and occasionally above) I

the action threshold level.

By agreement with WDOE, the Seattle District, Corps of Engineers, analyzed alternative dredging methods and equipment, disposal ,nethods and sites,

and site control and treatment practices that may be applied to Commencement

Bay sediments (Phillips, Malek, and Hamner 1985). Concurrently, the US Army

Engineer Waterways Experiment Station (WES), working with the Seattle District, developed a decisionmaking framework to specify testing requirements

and methods and provide guidance on interpreting and evaluating test results

to determine whether management restrictions are needed to dredge or dispose

d of the material (Lee et al. 1985). This paper discusses select results of the

alternatives analysis, briefly overviews the decisionmaking framework, and

* identifies a number of management issues associated with dredging and disposal

of contaminated sediments.

ASSESSMENT OF DREDGING AND DISPOSAL METHODS

Primarily an assessment of existing information, the alternatives analysis for Commencement Bay was based on three evaluation factors: (a) cost of

each alternative, (b) degree of contaminant confinement and release resulting

with each alternative, and (c) considerations and limitations specific to each

alternative (e.g., equipment and site availability, method efficiency, equipment depth limitations, sociopolitical concerns, and other indicators of practicability). Characteristics, operational considerations and control, and

equipment considerations and modifications for dredging contaminated sediments

were described for each dredging alternative.

The two basic types of dredges addressed, hydraulic and mechanical, were

evaluated in terms of contaminant loss during dredging. Special-purpose

dredges (many developed in Japan) that have been designed for contaminated

sediments were included in the hydraulic dredge category. Three generic

disposal methods for contaminated sediments, confined aquatic, upland, and

nearshore, were examined in terms of their strengths and weaknesses in

successfully containing various contaminant classes.

Chemical constituents associated with sediments are unequally distributed

among different chemical forms and sediment phases depending on the physicalchemical conditions in the sediments and the overlying water. When contaminants introduced into the water column become fixed into the underlying sediments, they rarely if ever become part of the mineral structure of the

sediment. Instead, these contaminants remain dissolved in the sediment interstitial water (pore water), become sorbed to the sediment ion exchange

portion as ionized constituents, form organic complexes, and/or become involved in complex sediment oxidation-reduction reactions and precipitations.

Dredging of contaminated sediments causes short-term loss of contaminants from

gas, interstitial water, or solid phases. The dredging method also influences

long-term contaminant losses at the disposal site.

Contaminated confinement and release during dredging and disposal were

addressed In terms of three generalized contaminant classes: volatile,

soluble, and sediment-ipound. These classes refer to the phase (gas, liquid,

solid) for which a~ contaminant has greatest affinity and in which relatively

S I 106
higher concentrations might be expected during the dredging and disposal process. The authors recognized that contaminants will partition and move between these phases to differing extents based on a number of factors. The

classification was used solely as a basis for comparing dredging and disposal

alternatives using existing data and information. No specific list of contaminants was developed.

Dredging

In Puget Sound, dredging normally occurs for one of three objectives:

(a) maintenance or construction for navigation purposes (the most common);

(b) projects where the dredged material is sought as fill; and (c) for sediment cleanup efforts. While much of the marine sediments in Puget Sound are

relatively clean, dredging of contaminated sediments is common in the urban

embayments. Dredging objectives for Commencement Bay include: (a) Federal

channel dredging about every 10 years; (b) a large (2 million cubic yards)

waterway fill project proposed for port development; and (c) Superfund contaminated sediments removal.

Characteristics of the dredges evaluated are summarized in Table 1.

Evaluated on the basis of sediment resuspension at the dredge site, specialpurpose hydraulic dredges (e.g., the Oozer dredge) produce less resuspension

than conventional hydraulic dredges, and, with the exception of hopper dredge

overflow, conventional hydraulic dredges produce less resuspension than conventional mechanical dredges. While mechanical dredges do not produce a

slurry, c'aventional hydraulic dredges produce abundant slurry water; specialpurpose dredges fall somewhere in between. In addition, hydraulic dredges

produce less resuspension of solids at the dredging site and have a higher

removal efficiency for liquids and solids than do mechanical dredges. However, using a hydraulic dredge to obtain high removal efficiency at the dredging site involves a trade-off requiring consideration of effluent quality and

potential treatment at the disposal site.

There is no hard and fast rule to selection of the "correct dredge."

Different dredging methods appear more appropriate for certain contaminant

classes. If concern exists for loss of volatile contaminants during dredging,

mechanical dredges perform better than hydraulic dredges. For sediment-bound

contaminants, removal efficiency is greater using hydraulic dredges than

mechanical dredges and appropriate technology exists to control solids at the

disposal site. Soluble contaminants can be removed more efficiently by a

hydraulic dredge, but are difficult to contro" at the disposal site and may

require treatment of the effluent. Mechanical dredges using a watertight

bucket offer an alternative to the water treatment concern by eliminating or

reducing the slurry, but could necessitate double-handling for some disposal

opt ions. %

A variety of modifications to dredging equipment and operation are appro-

, priate when dredging contaminated sediments. Dredge equipment modilications

that appear most promising for hydraulic dredges include the walking spud.

ladder pumps, in-line production meters, and degasser collection and treatment

(in the dredge furnace) system. Use of large, watertight buckets appears.

promising for mechanical dredges. Operational modifications for hydraulic

cutterhead dredges include minimizing cutter revolution speed, controlling.

swing speed, and not overdigging the maximum cut depth. For mechanical

107 A

•.7.
-4 P U

No 0 u 441

u 41 CNi C14 CN 4 CJ 

4J c 4- - - 03 

4-~~ 4->)4

V) 4-40 - r

4.~~ U 4,4 ~ 41 -

Q)i cc14 0 Q 14041 

4- 4-H 44 4 0: 04+4 4+ 00 0

E -11 00 C) 0 0' 01L~hi zi - '. .0 '0 ". 4 - '0 . .- 410 4 1

-4 -4 3tj~

H~~~~j 0 4H -. ~ J4- 0V 0 0 - r .Z m- = -0 -4 U

C ".4 (0 " 1 0) c

H*-4 m3 m r C

CD Ci) - 0 C) 0 00 C4 0

0 4- Q C 4-) 41 ~O4 m 0 w : 03 4r) Lr) ' Le) 0 - 0 0 C) 0 -4 E CD)

u' () = 0& (VC CD) *41" 

Q0 Q) cu ) r.I0 0 0 0 0 Ci) 41 (n4

0m0 .1 00 m 41

2O'-~Lr .00 * J ' U 1 0 w~

~. '0 ll . f~L/ ~ - (N - C~ .r-N 0 oU -4

).) 0) 0.C 0 0 0 00 a C1 0f -4VI 

0~ Ur L4- (NJ Ln (N) 0c. MN '0 L 0 r--

L4.) u Lc: 0. -4 0 mN 0 1 0CV

Ci) C4 01 041 4) 0)0 r-r 4 ) mCIM

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;> 41o LrI Zr (Z Z) 0r (- ~10 T W~ 

: C Q U I 1 - 0 0 cc -4~0 (2 . 1 41 -. j 4. o u oca Q

>1 c- - - g. C 4-0 w 0- I.

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0 cc0E0 0 0 0 0 Cu Ci) 4 Q -

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% % % % % %V %
- - . h " 

dredging, sweeping the bottom with the bucket, and digging fine-grained sediments from underneath (heavy buckets penetrating through soft surface materials) are practices to be avoided.

Short-term losses of soluble contaminants represent the key factor in se- %.P

lecting dredge type. These losses can be estimated by assuming a slow rate of

contaminant transfer between phases during dredging and using a modified elutriate test. For hydraulic dredging, test results can predict weir concentra- .

tions (total and dissolved) expected for a given site, and predicted values %

can be compared against decisionmaking criteria with or without consideration

of dilution in the receiving waters. It is more difficult to predict losses

for mechanical dredging. Bucket size, sediment characteristics, and other

job-specific factors will influence the actual losses in the field. As a

usual rule, for dredging large volumes of low-level contaminated sediments

where a low percentage of the contamination is soluble, hydraulic dredging

with particulate control will provide greater confinement per given cost than

will mechanical dredging with watertight equipment. As the percentage of soluble contaminants increases, the "confinement-per-cost" indicator will begin

to favor the mechanical approach.

Most projects will contain all three classes of contamination. In terms

of overall contamination, sediment-bound contaminants usually represent the

bulk of the contamination, suggesting use of hydraulic equipment for maximum

recovery and extraction efliciencv. The amount of volatiles that may he lost

during dredging Is not likely to be a source of major concern in many projects.

As the types and amount of soluble, or easily solubilized, contaminants increase in a sediment to he dredged, reater consideration should be given to,

the (ist and environmental Im patt of mechanical dredging with waterti ht eIj -

ment relative to that of hydraulic dredgin' and water treatment at the disp,-"i

sat ite.

D i sa -"p

Ilt-re I re (,t,,r si-i, tpt iiny Ir (Isp,,,i I ut d red ed materlal: 1 ,pen

waiter , ilnconl ined; coni Ti' d aquat i( ; near-bhore ; 171d up latnd , Pigurei< ,,t. d ii.

()pen water, unu nt iTed I i spi ,i I i - the h i, tr 1 , t rad it i,,n,, r t : e %

ray . tti,,ri ,redgin): in P',et .Sitnd; the ,uther three are ((II ired ,ipt i ,In's.

. jIned ,,iat ii disp, , iiv ,lve. the placemviit ,! c eatier se , (- ett .. ..Vvr

m,,re c'unt.,rinuted '-ediieitts (( ,iing!) to isute tie cTctdrn t in. ,

i t ver i(: - ' , a T h e p a ed in T r1( r ,I ,re ,r Up ! i di s , a i t. k e "t -

n Iq,. ir.prtant ti rt-e-r ,er t hi t tf,.re Ire tr 4. .i: . ard ,.-i:- -.

tr)ment , T Teqle:i,'e ti a I i pt in) HTure- I* .ti , W tA it,

tiwa tp .; ,r rmute' P r l et , that sediment iIttminat iin : an tIt. I a-. .

r:d in lale .', the irst three patiwuvs invol ,, witer . ., .

wter ,!i chirged Irim. the itt. d,rinr ictil drv.dd ,i: ",.. '!! *- : i t in

th.It it is, -uirta f water d ( i ]trged :r - i rearsire * - ;~r ti 4- ! v t it

i r m i ranitI 1 ,r pure, wtIr e:.:trde (I-di (.nt c- d. (I, iirnI i i , , ,(I,-.-t -i ' 

I " )t etcd. e.e.o ! ote is t"U It 1 rI,-witer , .; A, 'tf It

i p t I. I i t It dred i i 1 1 1 t: i t I., t i, i lt 1 , ' , ' 1 I t , w 

I ' "

(i.e. * , nve t ,r) it - I- ,in mov'e t r1,1 u 1 t i. w.It,. i . 11- i

% iP t .nIT( 'ni r.a i I , in ,pta'iks ' d li trilut. nt1ri' tI ,t I, !W .

-,i I t'e er r rsI e.tIvct di r t I%. it C .- rdne- TICd 1) p 1 T_ t " f .I t -I

t P'r Kt.#t pert re Cta it r int it t i 1 i, t i -I ' t !I ,TI 

tnli t i

% f"o4

-..". ..-'.- ' '* --'. .- , > .- . .- ." , v -- .' -• w- . . .- - " .' " - . . - " ,
1. J

P,J

CONVECTION

SOLUBLE

DIFFUSION ~ CONVIECTIC, -

BOTTOM--- BIOTURBATION

CURRENTS DRDE

MATERIAL

SOLUBLE ,EXISTING

DIFFUSION" BID TOM

CONVECTION

a. Open water, unconfined

60-500-DEPTH OF STORM

SOLUBLE

DIFFUSION

CONVECTION BIOITURBATIONBOT-TOM3-FT CAP OF CLEAN SEDIMENTS

CONTAMINATED

SEDIMENTS ONDIER~hATFR

OL U B LE

NATURAL OR DIFFUSION

EXCAVATED CONVECTION

DEPRESSION

1). Aqua~t iC ccon t I ned%%.

I I ~U!I . . I~p(n wait r, uncon i Ined and -lqnIt Ic ('()"I1 ilI(( dic~p(w1 I
%U

.0

INILTRAT ION

CON VEC-ION

~cj~ UPSA1URATEO ONAI 9 TDPUPN

STRATED !;ED ET

VOLATILOZATLO

DDIFFUSION

NIKEAON D-3 DK

* C.4OUNO ATER LEVE

* N~irhoe and ian dspsa

VOLATIIZATIO

DIFFUSION

CAPILLAR

PREIPT IO

MOVEMEN
%~.#

TABI . PATH AW . 7A A '.

Water losses

Effluent

Runo f f

L.eachate - ,0 1 ub le di:t1 - i,n.

- soluble convectt,,r

Uptake - plants

- animals -"

Part iculates - during dredging

- effluent runoff

Volatil izat ion

volatilize to air. These processes are on diterent r, .ri'%,e irmp, rtan~e

different disposal environments; and to confound r.iters :urther, dit erert

classes of contaminants will behave different!, in dir:erent ervirnments.

Each assessment is, therefore, sediment- and environment- ei:it.

Contaminant mobility implies a quantifia!le rate process ,and i a :nction of the chemical species, the solvent (w.,.ter), the t.'pe rot 'oil .-,iment

matrix, the physical state of the system, chemical concentration leve', and

certain geometric factors. These factors are shown in Table '

Nearly all chemical contaminants are st luhle t,, s,,me degree; t!,e degree

of solubility depends on a variety of factcrs and can change as -pecific conditions are altered by the act of dredging, during transport of the dredged

material, during its discharge into the disposra site, and following its dis- .

posal. The first three actions occur during a very short time frame and their %

influence on contaminant mobility is relatively instantaneous. !nng-term condition changes and effects on contaminant phase. particularlv with recard to

solubility, are of greater complexity. -,

A percentage of the potentially soluble contaminant :raction wil' he in

solution in the sediment interst.tial water. The remainder will be bound to J'

sediment particles. Thus, an equilibrium exists within the sediment phase,

with the fraction of chemical contaminant potentfally available for short-term

release during dredging or disposal operations approximating the interstitial

water concentrations and the loosel'." bound fra(tion in the cediments.

Once deposited at the disposal site, reten i(1r it soluvle ,ont.mi'n.rt"

becomes difficult to assess. (ontaminant Ir;rt i ons that wtre ti v I r u und tthe sediment particles can, over time and due to i'terinc o0n1d it ions, ,,e-rne

more prone to go into solution. This is olt er tIe ':ico ,r fivv met i- whet 

placed in upland disposal sites. Under so t,,ratedl cin.tion-, m;ITnv met.111 !-emain tightly bound to the sediments. In unsaturated ,ot U in,' where o:. idation can occur, these contaminants can 1)ecome mr' - .n: -a' read

leach to surfa(,, runoff or ground water perrolir," t;r'i. t a , itt'tit .

Changes in pH have similar implications :or ther ',r ,

..- -d -.. .- ..1.n, . .. ..- -. .- .. . --. ..-.. . ,-,.. ..
- 

. V ° . ; .'-' * *, - . '3 , -U " . . : W • *~W U W . -. , = . - ' 1 q- t w.. i , .

ABI~~~~~~~ V N7T Ak N i-K AI ' J

,">,.iar weight and chemical structure

SolubiI.tv in water and vapor pressure

Ii, :usivitv in water and in po re gas

P1 r t it ion coe I ici ent s and 1enrv 's constant

IvenIt S ( pore wa t er and pore gas )

'(%Ietcular weight of water and gas

,ncentration and partial pressure ot other species

>11 i ;ediment matri.'

Porositv 1micrlo, macro)

i-ra'n size (average and standard deviation)

Permeaibilitv (water and gas)

Or~anic fraction and Ion exchange capacity

Water content .or soil)

Tortuos itv

LeveI and depth o bioturbation

Fluid properties

lemperature, pressure, and phase ((, L, S)

ater flow rate and direction

Cas flow rate and direction

,otal contaminant concentration level

Low: 50,000 ppm (wt)

Hii :l 50,000 ppm (wt) %

(,eometri factors

Length ot diffusion and convection pathways

Cover layer depth

Pisposal cell dimensions -,

In aerobic disposal environments, factors discussed above may have an -

even more pronounced effect on contaminant release. Brannon (1983) reported

that sediments high in total sulfur content and low in CaCO 3 equivalent concentrations generally attained the lowest leachate pH's when incubated in an

aerobic environment. Sulfide oxidation to sulfates with consequent formation

of sulfuric acids is one mechanism postulated for this pH drop. In sediments

from Seattle, Washington (total sulfide: 1,214 ppm), incubated under aerobic

conditions, pH dropped from 8.2 to 6.6 in I month, to 5.5 in 3 months, and to

4.! in F) months of observation (Brannon i983). Arsenic release from these

sediments was associated with the pH drop. Aerobic disposal also affects organ i co ntaminants: decav of 110C in upland disposal sites can change the mohflit. o: these contaminants.

A omparison ot the effectiveness of the three confined disposal -wthods4- irrovide,! In Table 4. Soluble contaminants, or contaminants with the greatest pt.til to go int,, solution under certain conditions, are of hichest

% N7

% V , . • - % . . . . .. %. . . . . . . .. . ," .
TABLE 4. (OMPARISON OF DISPOSAL METHOD EFFECTIVENESS

Relative Relative Relative

(leochemical Magnitude of Available Environmental

Effect on Contaminant Control/ Risks from

I)ispoeal Contaminant Transport Treatment Contaminant .•

Method Mobilization Mechanisms Options Release

Confined Low Diffusion: high Few Low due to

aquatic Convection: medium dilution

Bioturbation: varies (ecological

Erosion: Medium risk)

U'pland High Diffusion: low Many Varies by

confined Convection: low contaminant

Bioturbation: varies (human health

Erosion: low risk)

Volatilization: high

Nearshore High in Diffusion: high Some Medium

confined unsaturated Convection: high (human health

zone; medium Bioturbation: varies and ecologiin saturated Erosion: low cal risks)

zone Volatilization: high

concern because these are less readily contained. In general, open-water

sites, especially those in deep water, have fewer transport mechanisms (e.g.,

air is absent) than upland sites and are geochemically more similar to in situ b

conditions at the dredging site. Nearshore sites have the most transport

routes available and are located in a very active environment. Control of the

releases and/or concern with the effects of the release must be considered.

For example open-water disposal allows for very limited control of releases

other than cap or liner thickness; the relatively stable physicochemical

environment retards contaminant mobility and encourages a constant, gradual

release to the overlying water body, especially once a cap has been saturated

by migrating contaminants. The levels of contaminants released will be low,"

(possibly unmeasureable) and will be diluted by the overlying water. The risk

of significant damage in this environment is low and would not likely affect

human health. Upland disposal, on the other hand, allows for the greatest

control, through design considerations, monitoring capabilities, backup contaminant intercept systems, and treatment facilities. However, environmental

risks may be higher than in open water because of proximity to ground water

and potential human health concerns. The nearshore disposal option allows for

some greater control of contaminants than in open water, but many fewer than

are available in an upland situation. In addition, the risks to the environment and to human health often include both those of open-water and upland

sites.

Site Control and Treatment Methods

The applicability and utility of various control and treatment alternatives for contaminated sediments in Commencement Bay are shown in Table 5.

114

2.'

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". ." -' .' "'. - " ." ' .." % .-, ." ." .,. ." ' . ." .' % - . ' " ' ¢ . '& '. ..% L ' ' ' '. ..' '. ' '. .' ..' "
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rA/

a0

P,1

14 4

-4 ZZ la r. Ia. 

m 0 12.

- F1

Z0 044 --

0 r4 4 4 -& aE Q). " 0 . 0.. > 1- > 0 1-a 9-4 0.H (n C'-4 .4 41 (14046

0 4 'J 44 Co 41 0 a- a)

Q U) z (I) - = -4 C/ 00-4 4):4P

U 4

* E- V)4 w 4) -4Z 1-O0

0(U-49-

.u 440'. 04 *- 0094 ~~Lz-~~~ Oa 4 W-4 W''X9 w 

E-40 9- )- 04 0)-4 w.

) Z En0 ) 0.

0- -E-Z a

E-4 00 C: 0 ~ CO -H 4- c Iu4 a'. -H .,-4 m " o 01 W) £z) 

:<J -H 4-4 '4 0. -4

L z.. co b -4 C 0. W1 

0 Cd -4 cc$ - VU 4 9-4 

(A rz-- P. t& 00 Ci44 1-c 00 r-jL 0. Q) NE4

-CC V) 0 l)1 ui 

E--4 04 0

-4

9. 4-4 (0 0 4)

Cl) 09- 0)U

-4 U)E- 4) co 0 ~ -4V

>z 9 r4W > 0

C. a m. 44 W)-(n44 Ww

9.~ .- .U ... .CJ . . . ... UI- .f 0
p. %

cr0 '0 m s

A~~j I c I

u~4c CO

-1-4

0 0 - P

W > 04- 0 -

4 4

0

cu -4 a

c~cjj

Q))- 4- rz

0. 0. 0--Q

co - V 04-

(13 Q) cu4

o) co v 0)

-0 > = 0 AW

(1 4) 0 13

(13 C

u~0 u I.0r

'11
is tahie i I lust rite'- that the degree of site nIth ubr %oto 

,tva iio]et reatment opt ions, docreYsef I m uplIand to nea rshore to o pen -wa te

d i ,posal. Y Ii s dec reas ing ton t rolI i s t ranslIa ted i n to reduc ed opport tin i t I.es to

de s ign Add i t onalI t reartmen t measu re s t ha t woulId prev.en t uincon t rolI I edl , sud den

o r ac ce Ie ra ted c onitam inan t re l ease iniito thfe enviJronmen t and, o r t o i vo id t 'eo

eX t reme e Xpe nse sI e (I i me n t r emovalI a nd re v oca t io .,i

1)re2in and Disposal_Summary *

Fo r hvd rauI ic ofredgi ng, t le re Iitt i ve I mpor tan( e ot losses, at variousc

t ime s atnd r om var io u.- phtas e,- dutr in g t hve sd ime nt hiandtIi ing p roc ess i s 1 i st ed .e

he low in ,rder of decreas ing i mpo r tan ce.

a. Short-term loss of sediment ndwater.

b . long-term I oss; of water.

C . Sho r t -t erm l oss vI voIa t i Ie s .

*d . Long-term loss of volati les.

e . ILon g- t ermi I o ss o f se dim en t .

Normallv, disposal will result in greater short-term los.s of sediment and

water than will dredging. Based onl the above ranking of importance, shorttetrm :Aedlment and water loss (luring ( disposal wil1l1 he the f irst cons iderat ion

*and the baisis t or se lec ting d isposalI method and treatment levelI. Con~rcurrent v , but on a secondary basis, the contribut ion of dredging to this loss

shoul(! be evaluated. I'lle next subsequent step should be selecting appropriate

treatment, monitoring, and remedial response to adldress long-term loss of S

Waite rhorne contaminants. (ons iderat ion oif items c - e above would depend on

s;ediment and site-specific conditions,. For mechanical dredging, short-term

los-s 01 sediment and water and long-term loss of water from the disposal site

'tor upland or nearshore sites) may he equally important. The proportion of

*part ialIlIv so lublIe contaminants in d isposed sediment that is avaiil]ablIe for

lait er I eachlinfg is i nc rea sed relIa t ive to t ha t i n hvd rau I ica IIv dredged sed i -

*met- s .The amount of sed iments and eas i Iv soluble contaminant s lost at the

t!x t rac to edialoncrselrelative to hydraulic dredging. Hiowe ve r, the

U.,c , watter t ight buckets ma'. reduce th is loss substantilal lv. r.

PAR El'I (AMN;

* A'ses;sing contaminant loss; during dredging and disposal usual IV involves,

est imat ing the port ion of the contaminants that might be found in the sed iment

i ift (,r ,t i t ial watt er . Vlii l e the pref erred approuich to th is iss-ue is to determfinfe the port ion empir ical Ilv through direct test ing, it i s al Iso possible to

tt-,'or vt I call' I; ( ci I cui la te t he sol Ib I e po rt ionl v i aitpp Ifca t io(n o: heiica na r t i -

t ion j uc , cet I i c i en ts , as a wa'' to f I av potent i a I probf I vm,,.and i denTt i t V cont am- .

i i nt s of c on v rn Y off-sr at v i yenr pro j ec t .-

hem i i i: h;-oe partr i t i on ing, init o rmait i on 1a)ppl ied t o selc Ickt c on t.am inain ts

rorn ' mmc'n'emomnt BAV ' d imlents hah een us;ed to ilIlustrate one ipproaich to a

reeni)g: vas;ess-ment 0contaimlniitedl sedimenits4. Ihile the evll ut iln is uiseu i''r-n.- ee in? rmit ion, it mus--t he e~jnphisi7ed thalt the Viluelk- Art'

.4-4 *-4*. * % -*% **** 
flV VW rfl f ni . flf W W VWVW1C b 

C WWV V~ W flV -WV- . - V- V W rWWV W W- -w

highly variable and that present state of the art cannot provide reliable predictions of contaminant behavior or effects without sediment-specific tfsts.

Equilibrium in chemical partitioning is often not present or maintained during dredging, such that kinetics must also be considered. Furthermore, while

estimates of contaminant loss in the short term (during dredging, transport,

and initial disposal) are possible, verified predictive techniques for longterm losses are not available. This turther emphasizes the need to include

long-term monitoring and remedial respoise capability as an integral design

component for disposal of contaminated sediments.

Partitioning of Metals

Example Commencement Bay sediment chemistry is shown in Table (). Metals

in sediment can be partitioned to numerous forms of varying mobility, persistence, and bioavailabilitv. (Gambrell, Khalid, and Patrick 197S list the

tollowing potential metal forms:

a. Soluble free cations.

b. Soluble organic or inorganic complexes.

C. Easily exchangeable cations.

d. Precipitates of metal hydroxides. .

e. Precipitates with ferric oxyhydroxides. P%.-%

f. Insoluble organic complexes.

Insoluble sulfides.

h. Residual metals. r'

Brannon et al. 1976 describe a selective extraction protocol that procedurally defines metal pools by their relative extractability. They suggest

that short-term metal losses during dredging and initial disposal are likely

related to the soluble (interstitial water) and easily solubilized (exchangeable phase) metal torms, the two metal phases most easily extracted in their

procedure.

Dredging and disposal of sediments can influence the mobility o1 metals

by changing basic factors that govern their phase partitioning such as pH and

redox potential. The dredging process may influence these regulating processes in opposing directions. For example, most sediments found in the (onmencement Bay waterways are low in oxygen content and consequientl]\ reduced.

The dredging process often removes the sediments to oXidizing environmEnts and,

or introduces oxygenated water. The presence of suliide under reduced condi- "

tions will precipitate divalent metal sulfides, resulting in very low solubilit:,.. Sul fides will oxidize under aerobic conditions, possibly rel, asing heavv

metals. On the other hand, metals may he present in higher coni'nt rat ions in 

sediment interstitial waters tnder reduced cond ft ions due to redu( t ion i" r"

and mnganese hydrous oxides wh ich ten(i to sorb or copreT ip i tate Mt.1l Is lndt

oxidized conditions (Kha lid et a I. 1 1 ). Wh ich of t ve;e two t10 trq wi ll I .I 

prelominate is specific to a given sedintent and dredging prije, t.

118

. . . . . . . . . - o

%M . . . • ° . . . . . . . . % " . % % % " * " . % " • .. •"
.tl " . ON '! t I A.MP I I > I I M F I 

Pr irmeter _ I I e . .. _ r -i .

,r, et d dt : h+) pe ren t .. .1F 0 . * e Tb+ i 't l f

' I ~id,, } p .r ent gilt: .... ' per~es - r ,,

lay: . pe rcent 'O

Metal, ,, ppm,

A1

it

(r gan i ,pph

C.tY

HM , P..\h(MU .

Hexa~h ,,r,,t t ad i eTit 7 W) '

]e t r;i i , r e t h v I e -i v 140

* l tal ,,rganic carb n..

** .w m, t ular we ight pnl vnuc lear aromat ic hydrncarbons.

t Hi vh mo I eIcular wei ght polvnuc lear aromatic hvdrocarbons.

i,.'vt- the number t)? variables that in' luence metal partitioning, estimate. t ,r the (,ommencement Bav sediment presented below are based on representat ive v lties derived empirical lv from other projects. Brannon et al. (1976)

report values 1()r soluble and exchangeable phase (easily removed from sedimentI me ,lt I rom various sediments collected around the United States.

Represt.nr.,t ive values for use with the (ommencement Bay sediment and the

range 40 vt1uv- zeen in the Brannon et al. project report are shown in

* Lil'le

I AKI t . RI P'RFSFNTA I VE AN1) kAN; G0F VAL PES FOR

SOLI'BI. AND FASIILY SOI'BI1.17FE) METALS*

Soluble and .asiljjlubilized, Percent

I e e resentat lve Va le Range o f Values Reported

IM ))} 0 ). )00 4 - 0. 0t)..7

.r U .,u.O0{1 - .'.

0.0004 - '.(8

I.

-C

- . . C * * *. ... ... "

-= "'° / " , I -" " " " " " % " " + " . .. . """"" "" " " " "" """ """*"" "
For the example sediment lable 8 shows that copper sediment concentratiln- o1t I, 4010 ppm would translate into i.57 ppm in the soluble plus ex-

. Irlgeible phast. , assuming that a I inear relationship exists between total

metail c,ncentrat ions and their respect ive concentrat ions in the soluble plus

eCx hngeablI phase. For zinc and arsenic, combining information in Tables ( -.

,nd ' provides estimates o1 I1.28 ppm of zinc and 29.1 ppm of arsenic in the

I,, I cbiC and exch1angeahle phase.

I'ABI.F S. (ASF ST'l)Y PARTITI ON IN VAILUES* . . . . . . . p ..

(7 (7 " '

P a rame t er s oc I I S

e t aIs, ppm

I t 11, 40() NA (.57 0.023

,n 2(0 NA 13.28 0.170

,s q, 70)0 NA 29.1 (0.440

(Irganics, pph . Pheno 1 3 H) i, 5O 146 1 %f

'T tt rach 1 oroethvl ene 1 40 I , 59() 7.9 --

Hexach I(robutad iene 7I0 8,270 4. 1 --

P( H 26 290 (,001 - O.jt() 0.010 ..

1. MW PAHs o ,0n 2 f6, 500 45 I 0

HMV PAH s 31 ,(0 5 I , 10 0. 4 10

* ' = hulk sediment concentration.

bulk concentration normalized to TOC content of sediments.

I = estimated interstitial water concentration.

IS = interpretive standard or reference concentration.

Part it ioning of Organic Contaminants p....

Blo)m et al. (1976) reported seeing no evidence that IOC in a sediment directlv controlled release of metals during dredging, as no positive correla- %

t ions between meta Is re lease and TOC or soluble organic carbon were observed.

For manv organic contaminants, however, TOC appears to plav a central role in

contaminant release and availability. Pavlou and Weston (1984) report that

the variability in interstitial water concentrations of nonpolar, organic contaminant!s is a function of sediment 'IOC and not bulk sediment concentration.

(onsequentlv, a first-step estimation of interstitial water concentrations is

possible by assuming thermodynamic equilibrium and using bulk sediment cheristrv, T(W content, and ii -ormat ion on the partitinning c(elfticient of ea(

c(ntaminant. Mar v of the necessary coefficients are avai Iat)e in t he I ,Urature; a summary of orgqinic carbon-water part it ioning coefficients, K for ,,

the example sediment chemicals is provided in Table 9. For the values shown

in Table 8, bulk sediment concentrati,.ns were t ir st normalized to TO( content,

,.nd then interstitial water concentrations were estimated using K values

from Table 9.

% % % "
TABLE 9. PARTITIONING COEFFICIENTS FOR

ORGANIC CONTAmINANTS

Contaminant K -

Hexach 1 orobutad i ene 2,000-

PCB (2-6) 4,600-,()0

Phenol 24

I.MW PAHs

Acenaphthene 4,700

Naphthalene 890

Acenaphthy lene 3,900 .-

Anthracene 7,400

P!.enant hrene 9,300

Fluorene 4,800

x = 5,098

HMW PAHs

Fluoranthene 45,000

Benzo (a)anthracene 37,000

Benzo (a) pyrene 300,000

Benzo(b)fluoranthene 500,000

Benzo(k)fluoranthene 840,000

Chrvs7i e 77,000

Benzo(g,h,i)Pervlene 1,800,000

l)ibenzo(a,h) anthracene 160,000

Ideno(I,.',3-cd)pvrene 4,100,000

Pvrene 33,000

x = 789,200 ,.

Tet rachl oroethv 1ene 200

ioaV i lab) il I i-tvv 

McFirland (1984) reports that is is theoretically possible to predict the

potential maximum level of bioaccumulation resulting in an organism from a

given sediment. Proposed as a first-level screening device to identify

important compounds and sediments worth further evaluation, the technique

, rIaculate- thermodvnamic bioaccumulation potential in lipid content of an

irganism based on bulk sediment contaminant concentration, TOC content, and

partitioning coett icient equations. Using this technique for the PCB levels

in the example sediment would show the following:

* a,. P' h bulk sediment concentration = 26 pph.

b. T) 8.8 1 percent.

C. As.,mmed lipid cuntent in animal muscle = S percent.

*121-" ,
d. TBP (thermodynamic bioaccumulation potential in lipid)

(26 ppb/8.83 percent)/0.52 (equation from McFarland (1984)).

Screening Assessment

Data on soluble and exchangeable forms of metals, such as that summarized -

in Table 8, coupled with elutriate test results, can provide the basis for

assessing potential contaminant losses in the water during dredging and ini-,*..

tial disposal. Developed by use of K values, the predicted water concentra- % oc

tions for organic contaminants can serve as a basis for assessing potential

release. Note that indications of priority contamination ("contaminants of

concern") as provided by bulk concentrations are sometimes reversed when partitioning is considered (e.g., copper versus arsenic, phenol versus low molecular weight PAHs). These predictions can be assessed by comparing them with

available interpretive standards. These comparisons, shown in Table 8, again

reorder the relative importance of various sediment contaminants. Predictions %

on potential muscle concentrations can also be compared with reference values,

demonstrated effects data, and/or other decision criteria to determine if further testing with PCBs is warranted. The two-orders-of-magnitude difference

between the estimated value (28 ppb) and interpretive value (2 ppm) for PCB

concentrations provides a way to weight the intensity of further testing of

these sediments.

The number of missing interpretive standards, and, in other cases, differing standard values for the same contaminant, highlight the difficulty in

completing an assessment of dredged material.

COST

Theoretical (or empirical) estimates of soluble contamination and bioaccumulation potential serve to emphasize the need for decision criteria. Consideration of cost is a second emphasis for the same need. The Commencement

Bay analysis found a very diverse array of technology that could be applied to

dredged material disposal, including solids/water control, as well as treatment techniques and long-term management options. Table 10 notes that increased control and treatment has a proportional cost- impact. Looking at

detailed cost estimates (Tables 11 and 12), dredging can go from $1.50 per

cubic yard to $9.40 per cubic yard with addition of a liner, to $15.10 per

cubic yard with chemical clarification, and to $20.10 per cubic yard with carbon adsorption. A variety of advanced treatment systems can push costs even

higher. As expected, the critical issue becomes the appropriate balance between environmental protection and cost.

DE(: I IONMAK IN( FRAMEWORK

To improve interpretation of theoretical or empirical contamination data

on dredged material and to assist decisions associated with high cost of control technology, a decisionmaking framework was developed for Comr.encement lay

(Lee et al. 1985). The framework is a staged management strategv designed to

assess, via a number of specific tests and interpretive guidance, the need tor

restrictions in dredging and/or disposal and to determine the appropriate

level of those needed restrictions. It has five overall steps: (I) identi:v

the potential contaminant ef tects at the disposal site, (2) characterize the'

1%2 %P

..-

.','-,z..-'-'.'-". ." " """ " " .' '"d "- "." -" "''" '."-. . . .. " -" " " " . . . " '' "'
I~..

TABLE 10. COST OF 1)ISPOSAI, AND cONTROL. OPTIONS p

FOR HANDLING CONTAMINATED SEDIMENTS*

Alternative Cost**

Disposal

Site preparation

- upland/nearshore $500,000't

Weir construction

- upland $25,000

- nearshore $35,000

Diking - imported materials $4./cu yd

- onsite materials $1./cu yd

Open-water vertical diffuser

- construction $50,000-$I00,000

- operation +$I.-2./cu yd

Offsite material transport

- truck +$.20/cu yd/mile

- barge +$.20-.25/cu vd/mile

Site control

Open-water capping material $1.40/cu yd

Liners - soil (volume) $16.29-18.29/cu yd

- soil (area) $1. 8 1-2.03/sq ft

- synthetic $.ll-l.50/sq ft

Surface covers $1.27-24.20/sq yd

Underdrains $2,500/acre

Sediment stabilization

- lime $10,O00-14,000/acre '-

- dust palliatives $1,000-17,000/acre

- water sprinkling $2,000/acre

- chemical solidification $40/cu ydtt

Treatment costs not included because of their dependence on flow rates (see

Tables 11 and 12).

U** US dollars, January 1984.

Average for potential sites identified in Commencement Bay. Includes

diking and weir costs.

tt Cost based on proposed treatment of 37,000 cu yd of material in

Commencement Bay.

dredged material by chemical and biological tests, (3) identify any specific

contaminant mobilltv problems, (4) design problem specific solutions, and

(5) prepare a site management plan, including any needed monitoring and re- -

medial response. -

Select ion of dredging equipment and design of a disposal site for a given

contaminated sediment first reqire specific tests to assess contaminant concentrations and types, to estimate contaminant release at various points during the handling process, and to predict contaminant effects under various

dispw-al conditiuns. Test results are then compared with predetermined 'd V 12-3

N.

...............".-. .."....".".. %,"- - - - . . .. . .. . . . . . . . . P ..
TABLE II TREATMENT IEVEI, CtoS' COMPAR I S).-

FOR NEARSHORE 30-ACRE SITE*

Cost ($1 ,000) . -

Uni t Cumulative

Cost Component for 4-Month Process Total

Dredgin 1,000,000 cu yd Construction O&M 1,500 1,500

:.evel I

Plain sedimentation 5,880 50 5,930 7,430

Chemical clarification 214 220 4'14 7,864

Filtration

Option I - Pervious dike 75 5 80 7,944

Option 2 - Sandfill weir 86 20 106 7,970

(Assume

Option 2

level II in Level I)

Precipitation 869 464 1,330 9,300

Level III

Carbon adsorption - Option 1 5,000 495 5,500 14,800

Ozonation - Option 2 1,600 300 1,900 16,700**

(As sume

Option 2 in

Level IV Level III)

Distillation 47,850 4,452 52,300 69,000 ,€,

Electrodialysis 24,850 827 25,700 42,400

Reverse osmosis 28,850 598 29,+50 46,150

Ion exchange 21,350 987 22,300 39,000

• Costs for site control and treatment at a nearshore site cannot be directly

compared with costs for an upland site; treatment levels contain different

site control options.

** Total cost includes Option 1, carbon adsorption, plus Option 2, Ozonation.

standards or reference values (i.e., decision criteria) to determine where

predicted contaminant behavior will require some form of restriction or control. The purpose of the necessary restriction(s) is to reduce (or eliminate)

the contaminant loss or effect to an acceptable level. Selecting an appropriate restriction method often requires additional sediment testing as part

of project design. Thus, a given sediment to be dredged may undergo several

different test series. For se.-iment "clean-tip" projects, these are the

following:

a. Testing to determine in-place hazard warranting cleanup (is it a.

problem" sediment?). ..

b. Testing to determine if restrictions are required to dredge and dispose the sediment in a given disposal environment. 'IThese tests ire

often tiered for cost efficiency.)

124

% ° 
.' ,

TABLE 12. TREATMENT LEVEL COST COMPARISON

FOR NEARSHORE 80-ACRE SITE*

Cost ($1,000)

Unit Cumulative

Cost Component for 4-Month Process Total r %

Dredging 1,000,000 cu vd Construction O&M 1,500 1,500

ILevel I 

Pla'n sedimentation 15,762 50 15,812 17,312

'hemical clarification 214 220 434 17,746

k. Filtration

Option I - Pervious dike 75 5 80 17,826

Option 2 - Sandfill weir 86 20 106 17,852

(Assume

Option 2

Level II in Level I)

Precipitation 869 464 1,333 19,185

*[ Level II I

"arbon adsorption - Option 1 5,000 495 5,495 24,680

Ozonation - Option 2 1,600 300 1,900 26,580**

(Assume

Option 2 in

level IV Level III)

Di.,tillation 47,850 4,452 52,302 78,882 -""

Flectrodialysis 24,850 827 25,677 52,257

ieverse osmosis 28,850 598 29,448 56,028

I exchange 21,350 987 22,337 48,917

* o~ts for .site control and treatment at an upland site cannot be directly

&rrpared with cofts or a nearshore site; treatment levels contain different

.it. contro options.

S* ,,tail cost includes Option 1, carbon adsorption, plus Option 2, Ozonation.

. v.ting to select and design the necessary restrictions.

,il 1c to rcpresentative costs for conducting the testing outlined

t.. tcrsriiakii ! rarmework. Not all tests are needed for all projects;

t,- ir. veci ic t,, the disposal environment being evaluated.

API, I A'I ! I S IN Pl'I;ET SOUND EXAMPLES

J .7-%

.d! , f t t t-', r.t t , ,_,i . ...

. . ? t e nt i'. t.. ,tcted 1verett, Wash., as its preferred location

- , tt I (,rrier group home ported on Puget Sound. Conii "'': Iv' , W l' a~id disposal of 2.5 million cubic yards of

* " : ,, , r . e, n ti!t, hrb or and excavation of I.1) nilion cubic yards

,- .riv,.: i Hj, to r-(, -n i,'ur- a Mole pier. In June 1984, the Navy

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0 0 0CC

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0 0 0 CC. 0 

0 C ~0 C00

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w Z 4- co C , -

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-IC 0k 0%CC - 1% C0 ~ 0 Lf'~ 0 ~ 0 1C26 0 0 

o 0 ~~c 0 ~ 0 0C C2 ~ -- I - I0 0 0. C2,
contracted with the Corps to provide them technical assistance for dredging

and disposal of project sediments. Applying the Commencement Bay approach,

the Corps tirst sampled and chemically characterized project sediments. This

characterization effort identified two distinct layers of marine sediments

that would be disturbed by the Navy's proposed dredging: one laver of organicallv rich, fine sediments (2 to 6 ft thick) overlying a layer of relatively

cleaner "native" sediment. The organic laver was found to contain significantlv elevated levels of chemical contaminants (metals and PAHs) and was

determined to be unacceptable for unconfined, open-water disposal. In the

Phase I report to the Navy, biological testing was recommended. Phase II

studies and report concluded that the top I to 3 ft of the native material

should be dredged and disposed with the overlying, contaminated fraction, but

that the remainder of the material appeared acceptable for unconfined disposal. Phase III studies are currently under way at the WES applying the

suite of tests previously described for the Commencement Bay decisionmaking

framework; these studies are scheduled to be completed in mid-1986. The Navy

is proceeding with state and Federal permit processing in order to meet a very

tight construction schedule. Their present proposal is for confined aquatic

disposal of the contaminated material (approximately 800,000 cu yd), on a

250f-tt-deep shelf in adjacent Port Gardner, using the remainder of the project %

material for construction of the cap. Results of the suite of tests will be

key to permit decisionmaking and final design of the Navy's dredging and

disposal plans.

Puget Sound Dredged Disposal Analysis

The Commencement Bay work brought a number of issues and options to

light; the Puget Sound Dredged Disposal Analysis (PSDDA) is a study to resolve

the major issues associated with navigation dredging. A problem-solving component of an overall cleanup program for Puget Sound, the PSDDA study focuses

primarily on unconfined, open-water disposal of dredged material. Sound-wide ".*$ -.

in its perspective, the 3-year study has three major objectives:

a. locate and designate sites for open-water, unconfined disposal of

dredged material. %

b. Define evaluation procedures for dredged material. These are the

chemical and biological tests and test interpretation needed to

decide if dredged material is acceptable for open-water, unconfined

disposal. resting and test interpretation for material requiring

confined disposal will also be covered.

c. sormul,, site management plans for these open-water sites, likely

-nvolvil-, a ,nei -erm and more carefully monitored approach to site

management than used in the past.

At the heart of the PSDDA process will be several key decisions (shown in

Table 14). These include whether to continue open-water, unconfined disposal

shown as 1; what level of chemicals should be placed and managed at these

sites, shown as II; and where the sites should be located, shown as I11. Initiated in April 1985, PSDDA is due for completion in April 1988, with a total

study budget of $3.7 million.

127

0. %
% ,4

TABLE 14. ALTERNATIVES -'OR THE PUCET SOUND

DREDGED DISPOSAL ANALYSIS

1. No unconfined, open-water disposal in Puget Sound

a. No dredging

b. All confined disposal .

II. Unconfined, open-water disposal in Puget Sound

a. No chemical effects in biological resources

b. Minor chemical effects in biological resources

c. Moderate chemical effects in biological resources

d. Major chemical effects in biological resources

I1. Alternative unconfined, open-water disposal site locations in Puget

Sound

I SSUES

Dilution Versus Confinement

The Superfund effort in Commencement Bay has significantly heightened

regional awareness of the contrasting management philosophies embodied in the

Clean Water Act (CWA) and the Resource Conservation and Recovery Act (RCRA).

In the past, concern about the environmental health of Puget Sound and its

effects on human health concentrated principally on water quality considerations and standards. It was assumed that dilution would reduce pollution

loading to safe levels and that these diluted wastes would be flushed from the

Smund by normal water exchange with the Pacific Ocean. Passage of the CWA of

1972 eliminated direct sewerage and waste discharges without permits and

required greater treatment of municipal wastes. Water quality criteria were

established for a few, major compounds defining levels of pollutants that ."

could not be exceeded. Research related to regulating safe levels of

pollutant discharges concentrated on "mixing zones" that would ensure the

proper dilution of wastes. Revision of the CWA in 1977 led to increased

monitoring and more stringent requirements for discharges, but brought no

changes to the dilution philosophy.

RCRA, passed in 1976, established a different philosophy toward chemical

wastes and contaminants, based on controlling the contaminants from their

creation to destruction (i.e., "cradle to grave"). Priority was given to the

late of contaminants, their long-term effects, liability of producers of these

contaminants, and the objectives of "ultimate disposal" and maximum confinement. (riginallv targeted for upland control of chemical contaminants, RCRA

makes no clear exception for dredged material that Is contaminated. Researchers and regulators began to discover that dilution to maintain water quality

standards did not resolve the problem of loading of chemical contaminants into

marine waters. Often the contaminants became or remained bound to sediment

particles where thev were available for uptake by aquatic organisms and,

through the food chain, potentially bv humans. In addition, other research

concluded that Puget Sound acted more like a giant bathtub whose water and

128

-v"

,. #" _, . '.,.-.-4 , ,,' , '-. .'€ '.'-€ ' 0. .€ ' '.. '.. .' .4-,€%. ,••-,-. ""
bottom sediments sloshed back and forth rather tian flushing into the open

ocean. Pollutants discharged into Puget Sound tend to remain in Puget Sound

and over the years chemical contaminants have accumulated in urban embayments

and are apparently causing histopathological and visible pathological abnormalities in local biota. P

Water Quality Versus Sediment Quality

Studies by the National Oceanic and Atmospheric Administration (e.g., / '

Malins et al. 1984) were the first indicators that sediments, rather than

water quality, constituted a problem potentially affecting the health of Puget

Sound. The evidence strongly indicates that protection of water quality via

application of water quality criteria to the water column does not appear to

be the best approach. Dredging rarely violates Federal water quality criteria

in the water column. Even the most contaminated sediments are unlikely to do 0.

so because the contaminants are predominantly bound to particles. So sedimerits are being contaminated even in the absence of water quality criteria

violations.

With evidence of chemical contaminant enrichment and apparently related

biological degradation at several deep water disposal sites in Puget Sound, %

questions and concerns have been expressed by agency personnel and the public

over the contaminant levels in dredged material destined for disposal in Puget

Sound. As a result, the R(CRA philosophy is being heard more frequently during

discussion of dredging projects: long-term confinement, mass loss, residence

periods, and a "cradle-to-grave" solution as the means to address the many unknown effects and fates of chemicals in the environment.

Management goals for Puget Sound are being shifted from the water column.

to the sediments, and new decision criteria are being generated to reflect

this shiIt in management. Increased vertical and horizontal stratification in

-ampling the dredging prism and complete chemical and biological testing of

the sediments to be dredged have become normal requirements.

* Mgulatory ',eed tor Simplicity

*" A fundamenta l problem associated with the selection of a management approach to contaminated sediments is the conflict between "technical adequacy"

and "regulatory simplicity." Sediment contamination and its etfects are inlamouisly complex. However, an equally complex regulatory structure is often

perceived a. too complicated to implement. This latter view is reinforced .7

when the time and cost of the technical assessment become apparent. This has

led to numerous debates on the merits of a technically adequate assessment Of

contamination problems versus the use ot a "best available technology" or

overdesign approach.

The "(;rav Zone"

Much of I'S law seems to be derived from a school of thought that lie] ,.

that it is possible to identify specifically the level of contamination that

is "safe" for a particular environment, such as marine waters. There are two

reasons why such an approach will not work:

129

t .. . . . .- . . . % % %" .'N%:
a. Thie def inition of a ''safe'' level is, of tenl Itt to sienci.; 'C lemi tthte t irst to adiIt that tit e rta intt it, aln ih d inT tV to i C

b. SaIe tv i s at rela t ivv t erm , req iir ing ai () i .1 aie udnlg it I:

Iferent cooI tirci, d i tfterent 't ite , iiiJi !I tr v1 o-nt ! t, k.~h,. Tinot

agree on what is an aicceptahle contarminant ri-4 'ir ~ t 1',1w!: ti

not

ihe product tt SI- i ent ifI ic uncert i int: lu t di l Itri i or i v0 c-- I , i ts o-cal led "grav zone'' in contaminant (orirent rajt ion,, I h is ve~o requent Ilv orders oi ma$ nitide ) zone requi rt-, tec is'ion,, ito ase t T ~- e:f ects and r isks in ofii Ierent envi ronilents. It t 1o s is" te re t i't

regii It ,r\ vIlIe x ibi I it v'" i i ageT-nr' de c i ions on iridi v i d;iI p)re t t

Aqu~5jcihiposal as, a Viaible (I t ion

Aquatic disposa.l of dredged materialI is- undergoing cer iio re-a a i

at th 1s t ime . Mulh 1 oItis " rieeva ltz o I jtis atitjlii iT_ ug ist sl"i- as -

ate d wi th sed imet-hound ontaiminant-, or example , esltahlI i tbhing) (t jsl i'telnt

tes;t ing tnd cv.a luit ioni procedtires. hut mother aspect i , 1 ti: r ee v. i Hai t i o n

iq1a t ic d is;psa t' ast tile "I east pre! erred,' or ''last, r es ort d dis po - i o1)t i on,

ermlodliod in ciirrent Federal laiw (e.g. , "!,trinie Protection, Research, and >a.n(-

ttiar ie vAc t )I I) (ocean )umpinc Act). In trying to IniniMize iMp~l ts in) a

* 7'gle eli rumerit, stch is tile waiter, it is ipls to dEscoiragei 4t, o

e~t t ir nt r it e r ii as" t i gh tlIv as possibIe . liut w i t It t te adven11t o t R(t%,% , h''Ir

a (Ii *er et ;b 1 i otph and t Ii a ''ha imm er p ro\%'i s i on o tr eniid in g Iaindo ti 1 1i in g, pot en -

tia it p)rol Iems a re reaid i Iv atp paire nt . 'Ihte aIt erna te pe rs pe ct i ve towa rds, aquat ic

d i yI("-; I is tt' cons-,ider i t at viali Ie d isposajl opt ion. ih e . tofva nc t:, of c a ppi n i

t l1in olog; v rt ke% t o thtis; chai tngwed( p e rs-p-c t iv e. t' Iti manyv a d vatnt ag es tin re-

*tairdl g cintlMin ITt Mobil it' , And the prestnt e of at reduced, butif eed eniv ironmt--i t , t he is o I it tion ofI many con tamIinnts- can be ve rx eff ec t ivu i n cotf med

ta71 t i, s i t t- Th e Co rps o f F itg in e urs ( CF) ha s r e ce nt I % e m ptIved ca pp ed(

1 1ips i 11 the ~uwaim ish Wa te rwa-. at iea t tIe , a sh., and ttie I'S Nav,. has-'

propost-dci ipping as, part of the ir hotmeptrtprosl

* Si 115,1 I- efnv i roitme nt 'e rstus

It i- I t i- n v i r onme-n t ASS es SMenTt S

be c t lyve , t e chIi tIai s elIect io of a d red(Ig ed maiit e r Iil (I s ) i Itop t itn is

very muiichI in'i ex er c i i r is k maitnaig e ment . Var vi ngp s it e r es ouiirc es var irIn g

siteC getciem i ctrv , vary ing contam inat Ion types and concent rat ion, etc., all

imp Iv that there are no ''r isk-i ree'' optitons . "He f irst ctn(-litsion of the

I- tongressiona liv mandated, $30) millI ion research program onI dredged materialI

Cl ndIc t et inT the? lat e 70 ' s, was : ''There is no single best dlispoisal environment , no panacea.'' This is why the Co rps active ly sup~port s F:PAs efforts On I

mulitimedlia, multienivironment assessments, which w ill eventually requireseve ra I c hanges i n F ede ra I I aiws tha t a re env ironment -spec i t i c . Ihe approaich

i s to ass each d i sposalI op t i on and i ts problIems befIo re selIec ting the best

opt ion.

,New 1.i ab iIi ty

A (Ii rec t repe rcussion of the inttent of tile S upe r!und law Ii a ''ew

I Ii ai I i t Y'' t hat anyone hay i rig anY t h i nlg to do wi tih conl tam i na t i On has to0

130
W kno~wl1edge. Ihi ilI it Cllded( 'cntaig ious' 1 iali i t;, requ ired to I tie] the

mpujrt und ~.s eco)verv program, ha,, set a clear precedent for contaminant

It r II! ; t1r t ers .~A ,, e ill1 ( tit I tr I ow thIi is I i ahbiIi t - can af fect pro jects i s

i! r ed V.'the p r t, itu , 1.I ref urout-ed iluwimishl capping project which involvedl

met KJIllit. r ed gnig 71)1 .d )ISediment contaminajted primarily with U

met.,.- aid lo)w-I( eve- P(4s . [,1t. , !))( cIn Vd! oft contaminaited sediments used for

t iic .pp i rg 11r( oc t we re i t ial IlIv to (,1o placed inl an upland area. [he State o

'iI nitnapproved the pro; jet t wi th thle condition that the Corps monitor ;O,

rft'e groun1[d waIter, and ; i t became' 1I-;' Ited, to' "! iX it .'' ''ixing'' ground

t er i nt a I tb %tr t h1)e aIssu iImetd I iwhit lv ; remedlatlion , it possible,

I IW. V11 trit rf, high IOs ts. itI irts eaIr t r, dait Ia ,availabltIe Itor uplIand le aciin g rr I.,, Iiti sh1 o rhe n t s r wa- in our v iew , an uncetbelaiiy n

tI uidg4rnen-t , IMo)re acce1ptatble I i abhi I i tv ri.-lF- inr volv-ed co-nfining the contain-

:na,It e l mt r i 1 w ithfinI th ;Iq *pa t i ( eni ro nmenTit. The disposal barge was disdrr1) er. r Vs s ON 41 1 - I t i) ill thle West Waterway of thle l)uIWamish

I .rv T- I eat tI e, IK leane r sandy ma ter ial 1 rum upst ream , in severalI

a rI g- id , wl as l I ret leased o'ver the depression. 'Ilie capping was hyvdro-

~tiI m on ito(7re Iat t er e ach ot(v e r l oad un tilI the c ap wa- i n plac e. As a

Kn .demon- t rat ion I"' the pro, ect was c os,-e Il% mon it oredi during const ruc-e

t in; ijonger tetrm mon i tor ing involIves use o, t ak ibracoire. Samples are taken

togt ftt q)i tl cheJ to (,- ap thtickness/ 'ltegr i tv and possible l eachtinrg.

ir thle iritb-t r i a I waste managers , thte hest protect ion f rom I i ab i Ii ty i s

e t dt t. be a (tt i nutusu -inavI ,-t calI t rac k, an ''ac count ahi 1 itY.'" Th is %

prnipln i dreddgd materiail ac countahi 1 i tv, combined with et forts totward

fbe e i e tns is t en cv in r e W IIt itt n s atn d gu ide]I tones , i s at:t the h e art o f it h e

1,'11111A t-! fort . AlIso1, d redg!ed ma t er ialt tes t ing is now more than j ust for enrInoMnt r* i 11pr, t ect ion ; i t is alIso a measure o t puss ibl Ie I tab iIi t:i es wiithI

v 1 I~ tIt'l ~er su. e ifnt rod uc t ion

lb ii s raiises, a c hi I I len;,e ais to whether (Iredginp and open water, unconfined

ps si tdci - ng con tami nat ion into tile Sound or simply re locat ing it

within tl, > ('Iind. '-Unce much dredging is done tor navigation purposes, with

TldiIgt ionI mon'iesi, it canIl be viewed defensibly ( ttt a certain ext<ent) as a mantgemnent t'pptrtunlitv to, decide where and how toi plIace again thle contaminants.

* rr hIs becomes more challenging is when dredging, fs listed ats a point

st51 rce 11n a maiss lotad ing fo muii a for the Sound . Are thle sediment contaminants

a I ridv ''loaded'' due to thle industrial di!,charge, or does dredging reload

* thieml " The answer depend,; on what extent agencies and dec isionmakers wish to

ta-ke advantage ot the navigation" dredging opportuni tv to address existing "hot

ISi rig le Technt Iogv

e rsus PrtoblIem Management

A re lated sp in-ut I issue is tine coot I ut between contaminant handlIing by,

spec if ied, perhaps "best aval ]abe," I techinologv and hand 1 ing by probl em ident i Iicat ion and prob lem-spec iftic management. Ini the CWA, different wastes (for

example, municipal sewage versus dredged material) received dif ferent handling

p ph is o p h ie s .Bnt RCRA , withn its sit itutory design standards, has involIved

dredged material with several questions. Should detailed tests he conducted

% 'P

A...
on dredged material to ident itv what priOlems" it might illse,1! tit1

t ions to those problems be des;igned, )r !-.iuld we minir i' test 111,! 2nd wi t'

a sing Ic-approach di sposal1 s i te design.

Two Cost References

Because 01 thfe many new i ;ies, j:ld *)Ce rns de> rk thed ih, -k- r-,i i ve W

have t wo re te ren ce po in ts t o ev~iIalut e t he vct i dre d I- k! ~tei . >' '-a.I

0 'I'le t ra d t o na I c os t 1i n-nt iinI me, iwt e l1)sa 1 p Ir

Cubic vard)

* Tile kCRA best ia i I tle technii ug-, I I- i~''*o ' perii' rid,

$4() to $6(j per CIh ic yard)

I n addressi ng tile CO'It ; 11tiMf )I irt riiiint '1i vit Iit I'!i'' ho 4,'

r.atvrial , the s;pli itters, andI limper-: wi 1 1 prdut' Itw, v er.i' r r Tt ~t

curves depending on flow thle'.' appl) 1, tf'vhIn)I1gV to;drs it (I FtC: tI 

Fikiit- I Ilustrtes, examp:e,, o1 these twoi *s)t irv."i -iv,,i thfit two) rv: cr

OnIce itsin cotor dred 'ed materiail (iF'-l the ij~it i(TIi' 'st

1;'ii wate r , ,iniint ined djipsasIl , Ind1 t he hih 's ( o :' ''7 ti vile" ( di'

aI I t te di ret ion1 ekAled in mi'r nd i':; I. i iic -11- 11$ u- i )T t tt , I -

inc st ,to :(Ient it' probhlers, Ind dtsi, pr~ilemr-pt-, i' ''u isa

to( T I In i Z. e COiist rll('t ionI Co ~t

ill ti(Orseqube' I thes e inci ,r eas t-d 't, 0 t t i ')nTIrg d'(I - het

ipp1)r'eh ton manog - jug ,n t im i iieted 'ed iret-i t, :inl 1 fi, h ''r e i Trpe ret v': I,

inlirv,%ed ac'i'iiiitil ii it, is thfe nieed t' -! rivg-lte r 1 1 ,n nl. r I'I, ( i Tit'r

mir';i,'er,'ent a , f)mprehenlS i ve 1,wP it qu;int 2i esIi mI n o~rr s thd

moit er ia i iI i a det.ij lIed inI.v enItor','- I the t d ips 1it e r esur{'- is e C F -

ii I. F) Iu low in,! thfe pith h)l1azed hv indut r iai waste manavers,; w ith th11e ir

m u I t im i I on (I I Ilitr r eg i )n .I I i nc i ne rito)rs; , mu It i iiser (I I p'sp I sit es 'I I

dr,-dgt-d mit erija1 ire ain obv i tm' next step. Yhis, ipprolt, t,) I), tO ii c n i I

A nd I 1 -onlIi Tied d i sposal. I, is th h:Ce)0s;t Wa-',' to ! , ucns r e q,1ir tecs , .it florY-d p ro peI

do, sili a1nd miitri n, i nd r';.im1 eiv -un it ah i I i t' vIn thle (Ireding 1 jrog-

'ure ii )Iont ro I Ve rsnus .)e'lime It Irrnva i

Ass essinTg p rongr e in 11 clanup I I r t requl rv- isL I I, t, whe it we P -r

el-in 11ip. ( inn s en s e (I itau t it t e 1 pitt'ttIt 1 I' I. I wj .a iti 'it I--

ina t i oi i 1 a1 I II I i T) t riti I I ) n p J) i t t t li e MI I- (n C . 11 i s i -, tI II 111A Ii t 1) T- I

t he c 1 e-iniup' p rogras- inde r wa v in se'''r, I Puigl-t "'iiiuI 1 rh ll I':' 1 li (c )

'ailt io 0 I 1d v I im11i iat io ul 'onlt amin at sor' to the aquai I iteiv iiimmct't

!'I isL is a reafo-i;n.Ih Ic se nt en,'e , as r,,iev i , aIi I( n e es-sa-rv iprih. hilt there

;I rev add it i onn I t h ings to tonis i de r

al. Many (it thle chemicailsL we i nd i n m. ir imu-e ite Pe1t T1 t eg. ii nd

(itie r pe;t ic ides and P( s) are no ong)er 1) 1' 1d or(10- .1Iwi (in

p)re s ent i ntu s tr ia I d isc ha rges. 1 In liget l SIImiIl 1- -sidi I or h it onric , co)n tam i natJ!in i s be ing I ()i nd eve '('i i n r,I'eit v d '~' i te d

sedi Iment s.

I %

%9

*,.* %~"**..*.*.** *.* .e, ~ **. %'~'*.'.* ''*** - .,.~ iL~%
- b

M M

C

u rI ~ ~ ~ __ _ C _ _

crL

to 0

ku4 a

LUU

LL4

_ I-----0)-o 5e%
b Current sediment cont am initt ion in urban are as is I ike Ilv the resu It of

.1 chronic,* long-term discharge. 1t' contaminated sediment,- are removed, it may he many years be fore contaminated scdiments, are reestablished given current industrial contaminant discharges aillowanceS . Combined with historic contaminat ion sources, this has

sign ificrant imrypIi ca tion to the relI at ive cos t e ffec t ivenes s ( per g ivenl

unit of reduction of risk to the environment and human health) of

'red iment removal versus source control. Both become of comparable

importance.

C . Most treatment experts agree that in the near term (decades), eft lueot control t echinology will st ill requ ire res idualI d ischarge of contamination. These much lower concentrations will take proportionateiv longer to slgniticantlv recontaminate sediment,; near effluent

dIischarge poiints.X

d .(. i ven t reatment pathway-lIen gth I im i tat iocns and the prospec t of 11ongterm residual releases, it appears, logical, though perhaps radicalW

to ext end the 1 oncept of 't reatment processes"' to inl ude the diments outs ide the effl Iuent pipe as "f urther treatment ." Th es eJ.

s~ediments could be monitored and periodically removed, resulting in a

mlo re cost-c: fec ti ye method than some prohibit lye advanced treatments,

Ind perhaps als 1hc e more risk acceptable. Given the residuals, both

bet ter source treatment and sediment cont rol should he considered as

co(mplementary in developing source control permits. At least it

would provide some discharger responsibilitv beyond the pipe.

e . ()n thte o thetr i de oft th1i S i Ssue , na t uralI sed Imen t at io(n i n Puge t

"ound, a long with biodegradat ion of somecotmansprid a

c onc e pt ualI, t houg h un kn own , a ss imjIla t ive capacity, for contaminant

of i so:I a r ges . The locat ion of , and possiblIe t ransport routes to, these

naitural graives,'' are also unknown. But it suggests that source

reduct ion may perhaps work as a long-term solut ion.

R1-FFFN CE S r

Mo'm, B. , Jen k ins , e gge tt , 1) ., aind Mu rrman n, R 1970. ''I Ile ct ofI Sedofim v it or gai ic Ia t t er o n M ig r at i oni oft Va r io us Che m ic alI (Jouis t i tuie nt s DuTir iniig

11 isp,,sa Io(, Dredged M1ater ial I' (ont rac t Report D- -7f-,C Army Fnginee r 1 a ter-%

Eas xper iment Stat ion, Vicksburg, Miss.

hrainnon , J. 1198 1. "'The Transformation, Fixat ion :mnd Mobil izit ion or Arson i

,'Ind An!t i mony vin C on tam ina ted Se dimen ts,' Ph. 1). Thesis, louis iaiia St ate tni -

vers itv , Baton kougf , La.

Pr annon , 1. , EnglIer , k. , Rose, .1. ,Hunt, I). , aind Smith, I 10 I f ''el1e S ct lyve

Anuilyt ical Part it loning cdt SedimetIs to I'valuati' Potential MIobilI itv of Cliemicalt ( on~t ituents During Dtredging and lDlspcs al Operation," Technical Report

US/,3 Army, Engineer l ,iterwavs Experiment )t at ion, Vicksb;urg ,Mi.

iambr elII , K Rhai lid (I , a nd Pa t r ic k, W. I4 Q ''Physitoclhemical Parameters.

tha.t Iegulite Mohiliiat ion and lmymolbiIi,at ion o)I lox ic fleavv Metls,''

lrd~edings ()I the Spec ia Itv Conference on D~r edlging and Its FnvironmlentailV

Ft f ects, Amer ican Soc letv oif Civil I ngineers, New York, N. Y.

1 34
.-.

11

Khalid, R., ;ambrell, k., Verloo, M., and Patrick, W. 1975. "Transformations

of Heavy Metals and Plant Nutrients in Dredged Sediments of Affected by

Oxidation-Reduction Potential and pH, Part 1: Literature Review," Submitted

to I'S Army Engineer Waterways Experiment Station, Vicksburg, Miss.

. ... .... "..::

L.ee, C., Peddicord, R., Palermo, M., and Francingues, N. 1985. "Decisionmaking Framework for Management of Dredged Material: Application to Commencement Bay, Washington, Commencement Bay NearshoreiTideflats Superfund Site,

Remedial Investigations," US Army Engineer Waterways Experiment Station, a- a

Vicksburg, Miss.

Malins et al. 1984. "Chemical Pollutants in Sediments and Diseases of

Bottom-Dwelling Fish in Puget Sound, Washington," Environmental Science and

Technology, Vol 18, No. 9, pp 705-713.

McFarland, V. 1984. "Activity-Based Evaluation of Potential Bloaccumulation

from Sediments," Proceedings of the Conference "Dredging '84," American Societv, ot Cilvil Fngineers, New York, N. Y.

Pavlou, S., and Weston, 1. 1984. "Initial Evaluation of Alternatives for

Development of Sediment-Related Criteria for Toxic Contaminants in Marine

Waters (Puget Sound), Part 11: Development and Testing of the Sediment-Water

F quilibrIum Part it ioning Approach," JRB Association under EPA

Contract hm-f1-6388, Washington 1). C.

Phillips, K., Malek, J., and Hamner, W. B. 1985. "Evaluation of Alternative

Dredging Methods and Equipment, Disposal Methods and Sites, and Site Control

and Treatment Practices lr Contaminated Sediments, Commencement Bay

Nearshore/Tideflats Supertund qite, Remedial Investigations," US Army Engineer

District, Seattle, Seattle, Wash. r

135.

%* %

25-.

-...

-':.'

*--::
EFFECTS OF SEDIMENT REMOVAL IN TOKYO BAY

Tsuneo Sato

District Port Construction Bureau

Ministry of Transport

Shinichi Kojima, Hiroaki Mori

Japan Bottom Sediments Management Association

INTRODUCTION

Although the removal of organic sediment is conceptionally understood as

an effective countermeasure against environmental pollution, few data exist

concerning the extended removal effects of sediment. To study this problem,

the Second District Port Construction Bureau of the Ministry of Transport conducted several surveys on organic sediment of Tokyo Bay to observe dredging .-

effects in 1982-1984. This paper reports the findings of these surveys. ..

TEST LOCATIONS AND TEST APPARATUS

The test locations given in Figure I (A, B, and C) have three different i

removal depths.

Portf Toe. P at ofchi

/"~ ~ ,r.. r . '-.

Fort o!. Y' o "la'

S50 som Figure 1. Test

of locations

T

aw -- :

-36

% . . . . . .
W. .-

The first test was conducted in 1982 at C, where a sediment depth of

120 cm was removed inside a steel circular frame of 4.5 m 0 , as shown in

Figure 2. Three release test pipes, one of which has a cover, were inserted

inside the frame and two pipes, one of which has a cover, were outside the

frame. When not in use, the release test pipes without caps were extended to

the surface of the frame by additional pipes.

z

':4

removed removed

10cm 80cm O

C) 0 0 0 0reoeIa

06 5m 05M

1.2m

S-777471 - I ... 7 ...-

C

Test Points A itim R lest Point C

Figure 2. Test points A, B, and C

The second test was performed in 1983 at A and B, where a sediment depth

of 10 cm was removed from half of a steel circular frame of 6.5 m 0 (area A)

and 50 cm from the other half (area B). Five release test pipes were inside

the Irame.

The test pipe, without caps were lengthened when not -in use in the sanme

wav 15 those in the I test.

RYJVASF "IES! 'IS S'i ITV'

r re UO e,;c 1 t test piIpe T I t t Ii it i t w ithout 11 aps ) ha d -a d iaiet er o I

" nr , :ind a Ien 2tl h , 1 ,(ii' mr 1 Ei I, rk, i fiChI piplt W.'; in'4Vrtk'd ilt<' tHt'.

tediment to I depth o! " k nm. est pr,,e dir,- rt ii lcm1tr;ittcd in Iiiir, .

T ' It fr . MW'Ii, t : ,w 't, p t,, ", ri h e , (!T,.i~ , ,. t - 1, , i: .1." -

r- -T t t 1"t rt° 7 t i ', I l ' , lir 

%°. . %..

.. • . . ., % &• .. .. °
VIP

,SCover

zIOI - Figure 3. Release test pipe

(unit: mm)

No Test I Pirlto

Test Ii*p

Figure ~..Test proceiliires;

CHA F M.* P(I IANT ('(N(FTAIM

A5- imp Ii ed b-, the vtirt ica ( lt iI r J hnt i,,n po Ilutirt"

F 1 urv ') , it il nitura 1 that ti Ve P" On Qnv Cu 1-t t rit I, IT 'I ~ ~i.e f ter sed irent removalI Viigure F, seow,. tw, k.am "IT. 1

eren1

Ocm ot setliment w.-s c-irriedi 'lit in ecptemher M'- I 1!- 07 CeTn t 1.t 7'i

;epter-.ber 1(48 intl were comitictetl ;evev ti:"e' !!uir %

O'n: t rat i Tn- i T t e tippr I ) )I r I',' IC eT t irt . T , ~ V

ime. I1he (Itterenet-. in poillit in) uor-ci" It i'r:-l''lit <' ~ I' ~'~i

raire .)re (I 1 1ii i1 l, WithI t imp'. Iii i - r- C ! h;t- I

rirt fu ui t c'' t iie roethit t i ,T 1 't I n

t i
oeter content(%) ignition loss(Z

0 200 400 600 c0 5 10 15

0 0 %on

20 -20-

~40 -40 -

so / 60.

K I

100 100

120 120

suif ei~/g)T-P (mg/g)

0 1 2 3 4 5 6 0 0.4 0.8 1.2

0• "

20 - 120-

0-

I,.'

E40'/

-60- 60/

~80 *~80-

100 100

120 1 120

COD (mg" g) T-N (Mg/s)

0 20 40 60 0 2 4 6

0 0

20- 20-

-40 -a 40"

60 .60

80 ,,80

Do 100.

_,_- _0_40- an

0

mm. S. D. TX

Fivuire C hanges in pollutant concentrations

ver-us Se diment depth

139 K

. .0 . ". 80 "..--

,b 4-

i'.'.Y ,m re 5 (:h n.e oll t.n.co ... cen r.ton
.%

control (outside) 100 5 - -"

80 - 4 a, " '4

I6 E 60 Control (outside) .. 3,' " "

o * ---. r

' 

- .o -- r.

0 40 " -0 2 d "Ifter removal (inside) I after removal (inside)

20 1 d.

0. 01

83 84 85 83 84 8s

S J M S J S I M S

Figure 6. Change irt pHl lttnt n " ' :

(inside -nd ,it-,:e t ..

100

T-,-

60 

-

4 0-

201

N,-
0 ... ,

. 2 83 04O85

I 5

-. VA S i M 5 M S J, ,.." 

-~ lj ocn ~j~e t O ihtsi u Fme

..%

das

"800 coo

P . ! Sulf ide...

4 0 0 80 '00 '20 '40"

M S I

'° i .. ...-, , . '- "* ' v i ti -. -."--"-.'c, n --' ti-m e-- -o- ,'"w'it"-h- 
ODCOD mq/l P- mil NH 4-N mq/I r,

5 5 11 5 21 25 20 .1 .l 0 109

50 O 200 0 %

%%

. .. .... so. .. .. ... A2

'# lfl Il 6-

P SD

150 '151 16

zOO 200 205

Ae

Release IWater

, Sediment

artitioned

Material

Pore Water

Figure 10. Change in pollutant concentrations In port, water

CHAN;E IN RELEASE RATES

Figure 11 shows the release rate,; In test pipes with imid w i t,,t Iit

outside the test frame. The release rates in test pipes witht p- it.,,- -ii'

larger than the ones in pipes with caps. This may he c.Iu! i ,., re.,r.

rial such as newly settled solids or floating c ediment whi, , ,t,

p i pes.

Therefore, the measured dati -houlld he ;.;'e,i ed ,

1!, ',rpi , material.

€ - re I. -;!jw- t fit- 9* red(Iio( t , i . A re r -j', .6* 

1' %

A6°
""T

S le

i ::

~NA,

s.

o --' - '

210

so-.

50 /OO

10

0 TO so 100 500 1000 J

Fe tm in Pan 64thl M

igure I I Release rates in pipes with and %-"e

without caps outside test frame

120

C049. 5&PoP) /vvt/dy

Co-7O. BNT-*)

o

T-I

•" %

40-

.5'.o *%

2 0 .0 ',Ty 9. -'4-

0 0 r .20c

, - .5- d "0 . *'*.O ' c * * *.' -

.*. *5* 5. *•5'.*.-- *5 5
" %.

Figure 13 shows the reduction of release rates in test pipes without

caps. In test pipes without caps the release rates decrease to a smaller

extent than the pipes with caps. As mentioned before, this may be caused by

foreign material in the test pipes.

100

so

j 60 0 -'

0 Figure 13. Reduction

of release rates in .|

Co-408(T-N) ma/r4/day pipes without caps

40 ~Co-75.3CPOd-P)

20 SePt. 984 without Cans

0* % %

0 10 50 120cm

Thickness of Removed Sediment

The measurements at test points A and B were conducted 12 months after

removal, and at C, 24 months after removal. Therefore, at the start of the

tests much larger quantities of foreign material had flowed into the test

pipes of C than those of A and B.

As Figure 14 shows, the release rates of PO 4-P at C is about four times

larger than the original. It is no wonder that the foreign material which 'e'.

flowed into the pipes during 24 months manifested a big release. The release

rates of rest point ( are believed to result from the foreign material which

flowed into the pipes before the tests. This means that the :()reign material

is rich in pollutants.

"lhe leve.- (of PCB were used to determine the amount ol foreign material

which had flowfd into the steel frame. P(h is relativelv stable in an environment ind is scarce in the lower laver of natural sediment (Figure 1 5 . . -

ThereIore, little P(B wa,. detected -t test point ( immediately after dredging.

/ fter i months, however, L;ome PCB was; observed in the 0I- toi l-cm laver .111d, at

pre-v4nt, is observed in the P)- to Ill-cm laver. This s g ts that 1oreign

miter i. does ] ,w int) the test po)int V rome

. ................ ... .- .........
.'.1 -... ,.

4 - i%

Ile

3 1C

Sept. 1984 without cap I "

2 P04-P

1 Aof T-N

0 12 24 months

Figure 14. Differences in release rates

between A, B, and C

(outside)

Aug 19S2

Ill (Inside) 

" *

I1..

" L -.

0 s i M s j M s , 'i

f~igurJ {h n g:. e in PCB concentration in " '

a. 

.5-

se~liment test Point C) . '-.

..........

• " 

• ".%.3,

(In ide

% 

,', 

II
EFFECTS OF SEDIMENT REMOVAL

Nutrient concentrations in sediment increase gradually with time after

sediment removal under the influence of foreign material such as newly precipitating matter or suspended sediment. This gives the impression that no

restorative effects can be expected from sediment removal. However, it should

be studied from the viewpoint of release rates. Figure 16 shows the change in

release rates with time. As Figure 16 (Case II) indicates, the release rates %

increase with time as the foreign material accumulates, and result in an early

increase of release rates, thereby cancelling the removal effects.

Figure 16 (Cases I and III) indicates the release rates excluding the

released volume from foreign material. Although some variations are found,

release rates generally decrease.

It is believed that the decrease in release rates in the early stages may

result from diffusion into the underlying sediment because the underlying sediment is clean due to removal of the polluted material. Diffusion into the

underlying sediment continues until both the concentrations of release material from foreign materials and in sediment pore water become equal. After

that the release rates increase again.

Figure 17 shows the relationship between dredging depth and release rate

of COD, PO 4 -P, and T-N released from the bed for 1 year after the dredging.

Both cases (with and without cap) show that the release rates decreas" with

increasing thickness of the sediment removal. This feature is much clearer in

the case with the cap.

CONCLUSIONS

These tests were conducted to study the restorative effects of sediment

removal. At sea tnere are many conditions such as tides, newly precipitating

material, and suspended sediment. These conditions cause complicated sea

conditions that require much time and plenty of data to obtain a decisive

opinion.

Our tests faced this problem. In spite of the unsatisfactory conditions ..

such as short test times and small test spaces, the test results gave us some

valuable data. f

In summary, we succeeded in determining the effects (it sediment removal

on reducing release rates. An even more signiticant finding of this study Is

that foreign materials accumulating on conventional sediment have a great :iI influ1,enc e. %'.

%J

~ ~r c .a..a.a 
140".

12 0 .-

Case II ,4 %.' Without Cap .. 100 

q

s-o404

20 LA 0

4,' 20 40 0

- 40 

120-

60

0 6 12 1s 24 t

120

so %

0 6 1 2 IS 24 jranh i'

012

. 4 * . - . 4..4 . J
1.4-

1.2 (Without cap)

0. d.0

0.8

*COD

0.6 8 f(f..

T -N f

0.2 ft

0 20 40 so so 100 120 f

Thickness of Remved Sediment (cm)

(With' cap) . f

00

cc 0

0

0 20 4 0 s 0 2

Tnickness of1 Remo~ved Sedirmnt (cm)1

'I - '. '1111 t c ' ~. i mt-lit T ren~t v;I re, f I 1 - ITf

. . . . . lflrti . . .T iz.. ll' ~h

%- .*tde.* %tt * * t . f, : . . . . . . .. - - f
DEVELOPMENT OF LEACHATE TESTING PROTOCOLS FOR

DISPOSAL OF CONTAMINATED SEDIMENTS

Tommy E. Myers, James M. Brannon

US Army Engineer Waterways Experiment Station

Vicksburg, Mississippi 39180-0631

D. M. Griffin, Jr.

Associate Professor, Department of Civil Engineering

Louisiana Tech University, Ruston, Louisiana 71272

ABSTRACT

A testing protocol is described herein for evaluating desorption characteristics of contaminants from

dredged material. The procedure relies on comparing

the effluent trace predicted by the one-dimensional

advection-dispersion equation containing an equilibrium source term with that from an operating laboratory column. System specific parameters (v, p, 6, D

p

K ) required to solve the transport equation are evalud

ated separately. Such comparisons provide insight into

the mechanisms responsible for contaminant desorption.

The procedure was applied to a highly contaminated sediment from Indiana Harbor, Indiana. Preliminary leaching data for two heavy metals, arsenic and

cadmium, can be interpreted as film-controlled desorption rather than equilibrium partitioning.

I NTRO)UCT ION

hottom sediments contaminated with organic matter, heavv metals, polychlorinated biphenvs, and polvaromatic hydrocarbons are present in most urban

waterways. When contaminated dredged material is placed In a confined disposal taci I itv ((I')", the potent ial exists to generate leachates that may have

adverse impacts on ground waters. When the potential for adverse environrcnt~il impact exists, disposal of contaminated material must be planned to

limit these Impacts by restricting contaminant mobility. To design facilities

.it ;vstems nec'essarv too sat istv s i te-spec it ic requ irements for environmental

pr,)tect ion, int ormat ion is needed (n potential Contaminant mobil ity. Lacking

4pe lcic pi.intitative information on contaminant mobilitv, project engineers

ofr . l ,rcl to ;i(opt contaminant containment strategies thait are possibl' more

c,nc,rvat ire tIn nec ;,ai r..- resullt ing in t revaqd costs without a comme n iiurAt., in, r ea se in envirnment i pr,tect T- ion . I f Ila irh te" (4tua] I t v Ind generat iO(l

r.it o,, ,.n .I P prvd it teo, the p, nt iaI ipr ts ot using .a W'F 1 or disposal ot

,',,trri n.iteo dredI4d mater ia' an be det,,r, irned, a ti lowiny, the most costet t i I t e de'; ign t he tit i I i 7'd.

.1 %

** * *l,*~ * J g r t ** %~ ~ .. Wfl~lts&. 7 f..ILILt.t .. k. t E 
At present, there is no routinely applied laboratory testing protocol

capable of predicting, or even approximating, leachate quality from confined

dredged material disposal sites. Testing procedures to predict leachate quality are therefore needed to fully evaluate the confined disposal alternative

for contaminated dredged material. In order to predict leachate quality with

any degree of confidence, information concerning the fundamental processes

controlling contaminant transfer from the sediment solids to the aqueous phase

is needed. J_ %

SCOPE

This paper describes research that is being conducted by the US Army Engineer Waterways Experiment Station to develop testing procedures for evaluat-

* ing desorption mechanisms that control leaching in contaminated sediments.

The theoretical basis for understanding leaching of dredged material is

briefly described, and selected findings from an ongoing study are presented.

TECHNICAL APPROACH

Hill, Myers, and Brannon (1985) have presented a theoretical basis for

understanding the leaching of dredged material. Several models based on mass

transport theory were considered for describing contaminant transfer from the

dredged material solids to the aqueous phase. Mathematical descriptions of

equilibrium, film diffusion, intraparticle diffusion, reversible reaction,

irreversible reaction, and solubility limited, kinetic models were developed.

The one recommended by Hill, Myers, and Brannon (1985) for application to

dredged material uses an equilibrium distribution (partitioning) coefficient

to relate aqueous phase concentration to sediment phase concentration.

The approach described below uses numerical as well as experimental results to test the assumption that leaching is governed by equilibriumcontrolled desorption. Sequential batch leach tests are used to estimate a

distribution coefficient for each contaminant of interest. The distribution

coefficient is considered an intrinsic parameter that describes contaminant

release from the sediment. This parameter is then used in a one-dimensional

mass transfer equation containing an equilibrium source term to predict effluent quality from a continuously leached column. Interpretation of batch and

column data is based on a comparison of the predicted curve to the observed

data. Hence, this is an integrated approach that combines batch data, column

data, and mass transport theory. A schematic of the Integrated approach is

shown in Figure 1.

The one-dimensional mass transport equation describing contaminant

transport in confined dredged material is

P( c. I ~ - / d 

I = buI di p vr.i- ,Irlon tet I icient Ior conitaminalt i, 1 t

'4IIO(OJ% phi "t, (o tltri lrlm t (otcei nt r t ion, Mc /l-

.. . . . . . . . . . -

%**.*:- . *2v .:.y..................-..-
dp ,

Z = direction '

V =average pore water velocity-, L./t

=sediment bulk density, Ms/L-3

6=volumetric water content of sediment, 1.311.3 S~

K d = slope of desorption isotherm, 1,3M

t = time

Details of the development of this equation have been described by Hill, Myers,

and Brannon (1985). If the laboratory leaching column is short, it may be possible to assume that the liquid within the pores remain completely mixed, thus

allowing Equation 1 to be simplified and written as the ordinary differential

equation, shown below: ~

dc./dt =-(Q/V) C - P/6)K (dc /dt) (2)

where V =volume of voids, L3. Equation (2) has the solution v

In /\C~c -V/OL( d t (3)

where

C 0=contaminant concentration in the pore water at t 0, Mc/L7 r

1. = column length, 1.-

Tile bulk density ~.vold x'oltie V ,and voluimetric water content

are obtained using standard soil test procedures. The dispersion coeff ic ient 1) is obta ined uising cont inuous flow coluimn rest; as described b%,

p

I evens piel (H ')Fhe pore water velocity, and coluimn length I are (+t~lineO3

rowr ColUtMn opvrit ing records. The in1 i t ia I Con1 t AMi nant C 1C Ocnt rat i onk

obtinied by% chemica-l anlyi ilTe desorpt ion coel ic t-ent K is crute 'm1 d

tded (1 1': thtie Colum IT)n uin g s e quten t ial hlt t k-st T! A i t or t le-. *t.

hiave lt'f e o b ht a i nt!d , * ( ti uat i,)n - ca n te v o I\%ed , Jand t Ie e ? ril i! t -W

(-,ntariinant 1Ientratt c in'- v er-u t p(,rt, 's me ('!'he ITrj: I-, 'i tr T" ,

u I' lue'i t c(ncent rait ir!- rrr 11: ('PC ratin (ilflin. lit, ie

i I e~ t I! e f I I OW iI I

e X' '-) re r i' 4' 11 to Ir IK I'. T*7 ' !I

tl 11 '
4 

a

Z >-

z 

(

z u co

UoU

z 

c

z2

ozU *0
PRESSURE OUTLET

PERMEAMETER

TOPPLATE-

+ - ..

---IEAC HATE _-" ,' + "r,, _' _-: =-_-- r C H A M B E R :- -- ; ,/'' _ I_... . . .

-' ..7.. NEOPRENE 0 RINGS

1 .. C..

::.:SEDIM ENT:."... . . -

,, ~~INNER RING :- i

w:: !. N : J,.,

PERME AMETER_9. CM TEFLON

BASE PLATE Z - GASKET

OUTE "-LE OUTER OUTLET ''" , OUER OTLET "+ k...INNER OUTLET

Figure 2. Divided-flow permeameter used for

continuous flow column testing

b. Column test conditions used to obtain the dispersion coefficient D

are identical to those in the laboratory column.

c. The physical-chemical mechanisms governing desorption are the same in

batc', tests as in continuous flow systems, thus allowing the use of a

Kd determined from batch studies in Equations 1-3.

d. The degree of dredged material saturation and consolidation in the

column is homogeneous and does not vary during the test or is known

and can be accounted for.

A SPECIFIC APPLICATION

• "The integrated approach is presently being used (October 1985) to assess

the assumption of equilibrium-controlled desorption of contaminants from a

" sediment obtained from Indiana Harbor, Indiana. In some reaches of the Indi-

,na Harbor (:anal, the sediments are heavily contaminated with oil and grease,

,,'rkanic, and heavv metals.

(urre nt testing involves using sediment maintained under anaerobic condit inTIs-; . (0mta,,rinants of interest are the heavy metals As, Cd, Cr, Pb, and Zn

.i- well i; s-elected organics. Prior to making comparisons, a value of Kd is

,,,r-~in, 1,r eaich contaminant (Figure 1). The Kd is the slope of a deSr'rr :, < cthorr nstructed from a table of equilibrium values for solid

, nta-' i n.nt -ncentration q and aqueous phase contaminant concentra- .'.

'r i ,olI ii ind corresponding aqueous phase concentrations are

cnct l.'+i1:1" ailv I eaching the sediment in batch tests as outlined in

dil sorprion isotherm is shown in Figure 3. ".'

15'3 S?5 ,.+.5,.,

.% .. ... %
TABLE 1. TF1si SlFlF

TFST I I,( I' A'XAr-o

Fo k MFITA:.S A:,

Step 1 Load sediment into appr-npi iit. ,

polycarbonate for metal, i-t, I -

contaminants. Add quff icient ~'tr .'. .

water to sediment ratio of Ii ii: .

tubes must be loaded to ohta ;- in :,

for use in leaching fresh ,e,!irrrt.

Step 2 Shake horizontally at IW' cv,''t- -:vrI

Step 3 Centrif ugE f or 3(0 min at 6,I r ir -,

metals. Prior to f ilIter ing., ce it rti<:

through acid-washed glass wol, !(r irer 1 .1 4

glass wool for organics. Sanp If- tr ~r~ v7, C i

repetition on step 3 using clean ~ti~~<.

tubes to remove oil.

Step 4 Acidify leachate for organic a T-.i't ,- e.

metals analysis with ultrex nitric aicid. tr m

organic analysis in acetone-rinsed a- r ..

for metals analysis in plastic hn-ttleq.

Note: The anaerobic integrity of the sample waq ma int~i ine, *irin ;! i-:> - addition to centrif uge tubes, shaking, cent r f ug~ir i n , !r.l Iq K C+qr

Figure i. i'.pic i ! ,r

iith v r 7

154
. , IrFnT reliable data with which to construct desorption

'.- ,ana ",r nirhor sediment was hampered by the oil and grease in

I ,mt. r ,the vigorous shaking used in the batch tests separated much of

. ' ,,T-, the sedimenit solids, resulting in a water-oil and grease emul-

. t wmi necessarv to separate the oil and grease from the leachate prior

rnamit .. analvsis in order to obtain K values indicative only of d

,-!" ent water interactions. As shown in Table 1, for metals this required J

,eritrituva.tion followed by passage through glass wool in order to avoid

!, in of the 0.45-pm membrane filter used in phase separation.

initial metal concentrations in the pore water were determined by centrinn the sediment at its natural moisture content and then filtering the

-1pi-rnatant through a 0.45-m membrane filter. The bulk sediment concentratimn, initial pore water concentrations, and equilibrium distribution coef- 'I.,

-ti-nts tor arsenic and cadmium are presented in Table 2. - '

TABI.F 2. BULK SEDIMENT AND INITIAL PORE WATER ARSENIC AND %dCADMIUM CONCENTRATIONS AND EQUILIBRIUM DISTRIBUTION

COEFFICIENTS FOR INDIANA HARBOR SEDIMENT

Bulk Sediment Co d

, mg/kg dry wt. mg/z ml/g

T. U 29.5 0.0137 7.47

1 20. 0.0047 2.87

",.'; -it , t the integrated approach is Illustrated in Figure 4. The

, t-'WT I i i gure ire measured contaminant concentrations from three

11* t,. !i t :he curve, In Figure 4 result from plotting Equation 3. In

. ,... rptn i assumed to be an equilibrium-controlled process

,r',, T* h' thlie dvorpr ion coet ticient, K for that particular

.. r { . ... ,tt-rh , .rve lctrmes no ,desorption (K = (P. For both

d

S. . , ,f riim, o' .#.p-r imenti 1; determined concentrat ions are lower than

o'! , ; t i, ) . ini the ippropriate vailuie of K d * In fact, the

i: the ,,ir% e- which a-;%ime no desorption (Kd = (f1. It -e

. t )T, .t , ri, irm, it terst it i,,i 1 ipiid I pushed tror the col umn- - ,, i I and I urn et . t ve I t op, . Thi1 (oI c , I l' ile to Ii

it i,)g ,ti t . -ed if-int part i'les that Inhibits , tam inant

'*"I + + , t , + , I: l M 0 T) t t I t fi ' i'l t-o', ll' p i!la ";e .

-t.. i Vt , , trt , jo,,re .( Juime trace shcWn In Fiwir '. 1oe-;

',,r t : r , .... ,,t l ii, , r11 '., t, i ck re, ,e I t h;it ,ccii' dturing the

r, *0 . r . A t ., - ,, . . . cl * I t i ro t v r" i I t e( , t P.o . d i m rt ' t

"", , ,cr , , m , iJ t i , cf t he et 'c tI c,, i - ci t ,.,TT

K. T T,1 r A . . tit. It c -,'K i l t t hi 1' s h t' r - l I t ici t t 1

" , Pt . W tr; p V i u., I w i I I . -e i c t t it ' r i i ,t . In ,1(1!i 1t .. e.

% %
0015 *- 1

E 0010 PRDCTDWIEOPTO

U PREDICTED

* m WIO DESORPTION

0006 * * * p S

DETECTION LIMIT

0,001

0

0 12 3 45 6 7

0006

000650

0004

00- PREDICTED Wi DESORPTIONV.%*

PREDICTED

-mpatr io ,t ;ir, nic in idlrn i.,m ,rifcentrit ions.~

n w ti-ii t redi I e c tit od i I-x.
V

.4.

tt- t .rv, in p r 1,rt ,s to (et ermine the di spersio, i r t he c I t rt-n, lie

*avai .li it- : t t il - nt urmati, r will aid in tile ,ng. ing, interpret.it on .

umr (!v ,(rpt i )nl dat a.%

An Integrated approach to leachate testing i nvolvIng batch and lumn

leac l tests and maos transport equations was described. The integrated P'

tpproach appears to be a useful tool for characterizing the process that governs contaminant leaching from sediment solids. Preliminary results suggest

that leaching ot arsenic and cadmium from Indiana Harbor sediment Is governed

bv an oil and grease film rather than equilibrium partitioning between the

sediment and aqueous phase.

ACKNOW . EDGEMENTS

The tests described and the data presented herein were obtained from 

"

research conducted by the IUS Army Engineer Waterways Experiment Station and

sponsored by the Chicago District, US Army Corps of Engineers. a.

REFERENCES

Hill, D. 0., Myers, T. E., and Brannon, J. M. 1985. "Development and

Application of Techniques for Predicting Leachate Quality in Confined Disposal

Facilities, Part I: Background and Theory," Draft Report EL-85-XX, US Army

Engineer Waterways Experiment Station, Vicksburg, Miss.

Levenspiel, 0. 1972. Chemical Reaction Engineering, 2d ed., Wiley New York.

. %

•, .- .,

' e

"4.-5 "- '::I
MFTHOi t i ESTIMArIOUN I)F MFTHYLIMFR(1'RY I 5 ()LVEI 1N11 W'AlER FROUM

I)KFI)(;FD MATERIAL. BY I'SINC, THE MARINI: (fP.p())D

Reiichiro Ilirota

Aitsu Marine Bi(logical Station, Kumamoto flniversitv .

Aitsu, Amakusa-Matsushima, Kumamoto 861- 1, Japan .

Motoo Fujiki, Shizuko Tajima , Junko Ajada

Institute of Community Medicine, University of Tsukuba %

1-1-I Tennodai, Sakura, Niihari, Ibaraki 305, Japan

a.

ABSTRACT

Floatable marine copepods (Acartia c'au.-<) were

reared for 24 hr in seawater containing sediment. The

sediment contained 0.002 to 0.003 ppm of methylmercury

and 32.47 to 59.01 ppm of total mercury. Before the

start of the rearing experiments, the sediments were

irradiated with sunlight for 6 hr a day for 23 days.

The population density of the copepods was 10 to 41

individuals per litre. The copepods were collected

and methylmercury and total mercury in copepods were

measured. Then dissolved methylmercury concentration

in the seawater was estimated by the use of the

correlation between the bioconcentration factor of '

methylmercury and population density of copepods, and

by the use of methylmercury concentration in the copepods. The concentrations of methylmercury and total

mercury in the copepods increased by 0.0045 to

0.17 ppm and 0.7 to 1.706 ppm, respectively. The

estimated concentrations of dissolved methylmercury

were 0.000012 to 0.00026 ppb. These concentrations

correspond to 1/100 to 1/6 of methylmercury contents

in the sediments used in the experiments. From the

experiments, it was concluded that short-term sunlight

irradiation and short-term exposure of aerobic -e

condition did not form methylmercury from inorganic

mercury in the sediments, but dissolved methvlmercury

and inorganic mercury into the seawater from the

sediments.

I NTRODllCT ION

In dredging it is very common for the dredged mtt erial to contain to.i

su,stinces. When inorganic miercury e>: is- in tilt idreeldgd maitorial, it is,

fearedi that inorganic mercury changes into me-thvlr1'eV'rv inl tit' .se(diment,: 1% , .

the irridiation -t ,nl i ght and aerobi c U(Mdit i, (Iu I i l mi M" 19,

19 1p,) f1 methvlr&-rcurv is f(rmed In the d redged minter i;a!, mI ,tHi h% ,,rtr'; wi 11

1'! 7)t the Ip I rTIt nt oII tt . w;t e r and ten the ri %,r ,r I w Itr wi I -

p,! !iltoI bv tihe metliv tIercntr,.. Iheretorv, monit,,r i , o! th, . 'i . tlt nt w t,,-

-~ A -. S .1_

-:'-" ' " '""""""" " """ " ."".. ". " 't .'''.f '. '.i-." ' '. %. '. .'d._ , .. '_" . .'.'. -''8
t rrm dredged .edim ent ponds is inl I spen sb . Howev r, the hi o 'n,,', trt rur i on

i-at, :'t r o me Nth\lmercurv is predom inant. ( ted tr thaLt th, Pith r, r k Ir-- rv 1 ,r1 

milzit ton rm water into 1 ish ex×ists and j, s etect;flje, the methW.TImerctir% (,acent rat in In theo water i.s so -,I ght that It is undetectal e.

f irta et al. (1982) reported that the neg,,itive corre!,atio ,, xisted he-

*' tween the biconcentrati an aof methvmercurv and the densitV of capepod;. : 1 e

met hv I me rcu rv accumu I at ion in to I Ish is a slow process, but the met h\' I me rcur% %

accumu lat ion into copepods is rapid and the methy Imercury concent rat ion i n

copepods reaches a plateau in 24f hr. There fore, copepods are useful indi( atars for methylmercury pollution. "lo develop a method of estimation for dis- C.

solved methvlmercurv into water from the sediment containing mercury, the following experiments were conducted.

EXPERIMENTAL METHODS

Experiment I

Floatable marine copepods (Acartia clausi) obtained from the fish pond at

the Oyano Branch of the Kumamoto Prefectural Fisheries Experimental Station in

May 1982 were used in this experiment. Filtered seawater was placed in a

500-Z fish-rearing tank. Bottom sediment containing mercury obtained from

Minamata Bay was added to the seawater in the fish-rearing tank so that the

concentration of suspended substance was maintained at about 500 ppm. Irradiation with sunlight and aeration with an air pump to the seawater in the fishrearing tank were continued for 6 hr. Then the fish-rearing tank was removed

to an indoor laboratory, and the copepods at a density of 15 to 41 individuals

per litre were added to the seawater. The copepods were reared in the seawater aerated with an air pump. The water temperature was 25.6 to 26.9' C

% during the experiment. After 24 hr, the copepods were collected with a

plankton net (mesh size was 328 1.im), picked out by using a needle, rinsed

* briefly with distilled water, and dried in an oven at 600 C until they reached

, a fixed weight. The dry materials were stored in a desiccator. Then

methylmercury and total mercury in the copepods were measured.

Experiment 2

Floatable marine copepods (Acartia clausi) obtained from the fish pond at

v the Oyano Branch of the Kumamoto Prefectural Fisheries Experimental Station in

June 1982 were used in this experiment. Bottom sediment containing mercury

obtained from Minamata Bay was placed in a 30-k fish-rearing tank, and filtered seawater was added to the fish-rearing tank so that the seawater came up

to the surface of the sediment. Then the fish-rearing tank was set outdoors

and the sediment irradiated with sunlight for 23 days. The weather during

this irradiation with sunlight was as follows: 10 days fine, 9 days fine/

cloudv, and 4 days cloudy/rainy. After 23 days, the sediments irradiated with

sun Iight were added to t iltered seawater in a 5)0- . fish-rearing tank so the

,ncentrat ion of suspended substances was maintained at about 500 ppm. The

t sbi-rearing tank was removed to an indoor laboratory, and the copep,,ts at a

den, it , ot I!) to 1 ind ividuals per litre were added to the seawater. Ilhe 

c,,pmp, , wert, reaired in the ;eawater aerated wi h an air pump. The u.:iter t e':- ,

1.r.trire w.is .4.Jm t o 7. ()" ( dhrirign the experiment. t e r .4 hr, t 1,, apepo,1 ) -

w,.r. , v, ted with a I nkton , nut (ries4h .li 't was , ,.m , ri n',d h ', 1% wii-

% F

%. ... . .
r r.,

t,, tu

ol'Iitr i tt were kIold; th, 1 Will the i" Iit . A*It 1 14 ;.

i. r ,',,Ie t M ! r' 4-It 1-, 7r' r i it , t it I C wa I , I t tt.lt t t e, ., I '

Stit l t. I'sT ;it t l 1 or t " t . T rI h . 1 t %. " I I tr t ' ,' ~ ~ r : t w : ( l t i , n t r ; i, *4 u I" .* i U i r C t ," ; i ~ I* I T ' c" 1- !1 t I i ti I i /"" '

t ;c i n t ? i Id I 1t~ i e l 't 1 1 , k wii D - t , I i'(l e i'ri ~ t ~ I,, ,:';I: ' " i ,t,

i,, d ~ ro: i i wI iT r t I , ; ~ 11 th e ;li,) I~ tit i .'r }li 'id t,,] (I t ii.cc t h,,l' lK ' "-

m:il'thl , ,ind¢ marlig,in],t , 

d ( i t)X i de . Yk r ci'l"' ill [t ; , ioll k-, t/ l ,,.

- %

I I me I ,*;, a tnm ic ad sorp1)t on pe c t ro ph( ,t oret rv. ..

An, I Vt i ia I Method of Iota 1 Mercurv .-

%

Analvsis of total mercury In the copepods and the sedinent 'as cndut t,.

as fo] lows: copepods were placed in an ashing flask, concentrated nitric icid ,

was added, and the flask was heated until the solition became clear. (oCncentrated sulfuric acid and 4 percent potassium permanganate solution were then

added to the flask, which was heated again. After ashing, IO percent hydroxvlamine hydrochloride solution was added to reduce the potassium permanganate

and manganese dioxide. Mercury in the solution was measured by flameless

atomic absorption spectrophotometry.

RESULTS AND DISCUSSION

The experimental results on mercury uptake in Acoart ,t i a'Q are presented in Tables I and 2. In these tables, the mercury contents of the copepods are shown on a dry weight basis, and the mercury contents of the sediments are rhown on a wet weight basis. The initial concentrations of mercury

in the sediments used in these experiments were as follows: in HH-I and HH-2,

methylmercury and total mercury were 0.002 ppm and 56.45 ppm, respectively; in

HH-3 and HH-4, methylmercury and total mercury were 0.003 ppm and 40.14 ppm,

respectively; in HH-5, methylmercury and total mercury were 0.003 ppm and

59.01 ppm, respectively; in HH-6, methylmercury and total mercury were

0.003 ppm and 32.47 ppm, respectively.

The initial concentrations of methylmercurv and total mercury in the

copepods were 0.069 ppm and 0.081 ppm (dry weight basis), respectively,. Alter

the rearing experiment, the concentrat ions of methvImercury and total mercury

in the copepods were as follows: in Hkk-l, methyvlmercurv and total mercury

were 0.028 ppm and 0.808 ppm, respectivyelv; in ill-. methylm rcurv and ota "

mercury were 0. ()I ppm andt (). 14) ppm, respect ive ly; in lih-I, metltvlmercurv adl

t'tal mercury we re .()qq ppm and I. 1.< ppm, respect ivtl; in l-, methIlr-,erc'nr., aid total m urc,rv were . ' pm , ainl (I'.. pp)m, r,'ep, t ivelv; in fIf-,

metk v Imercnrv nod t (t,,l mercurv were . i ' ppm inI I ppm, rcMpect ivol'; in

itil-h, ni tli I m'.olc,,r ',lrv ntI t ,, I i rc r, wer,. . pj t' ind . I -...

rve r,( t ive lv".

° . . . 1 . * . . . . . - . - - - .7.
..

T< ;I L I 21t

'T, iyt urn! ' e rt , 1nPt at ion

i Ti"' , t ,. jt I' . ppm , I)r' 'ei_6ht ,i.; be nsi tv'

ti. eIthv, ttl - Methyl- ) pepd.

r it . :'tmt' r . r M e r(tr-. me r cur ,, I Id I;/ I a s

"I. ' i.a 0,18 I0 

* {-- . (i * M I. ] , () . 0 1 1 17

,t - -- 0.()8 00T 9.~ --

IABI F 2 MER:lRY UPTAKF- IN (OPEPOI)S EXPER IMENT 2 f;"

.

Mercurv (oncentration Mercury Concentration P e

In Sediments, in Copepods, Population

Wpm, Wet Weight Basis ppm, Dry Weight Basis Density

Total Methyl- Total Methyl- of Copepods

Number Mercury mercury Mercury mercury Individuals/Z

HH-5 59.01 0.003 1.431 0.125 10

HH-6 32.47 0.003 2.152 0.353 13

Control I-... 0.081 0.069 --

%

In experiment 1 , the concentration of methylmercury accumulated in the

copepods for 24 hr was 0.074 ppm (average). This concentration was higher

than initial concentration (0.069 ppm), and it increased by 0.0045 ppm. The

concentration of total mercury accumulated in the copepods for 24 hr was

0.781 ppm (average). This concentration was higher than initial concentration

(0.081 ppm), and it increased by 0.700 ppm. In experiment 2 the concentration

of methylmercury accumulated in the copepods for 24 hr was 0.239 ppm (average). The concentration was higher than initial concentration (0.069 ppm), ..

and it increased by 0.170 ppm. The concentration of total mercury accumulated "',"

In the copepods for 24 hr was 1.787 ppm (average). This concentration was

higher than initial concentration (0.081 ppm), and it increased by 1.706 ppm.

In experiment 1, on the assumption that mercury in the sediments (the

;uspended n, tance is maintained at about 500 ppm) dissolves completely into

the seawater in the 5h)-, fish-rearing tank, increased concentrations of

metiv[mercury ,ind total mercury in the seawater were 0.0013 pph (average) aiJ

4 . I pph (., rain I, re'spectivelv. In experiment 2 on the assumption that

me (rrv in th, ;edimen (as ))) ppm (0 suspended s1ubstance) dissolves0V on-

,' lv jut , ;c.iwitot in the f ish-rearing tank, increased c one1- , r ,i t ; - ,n ,; o ,i w t .t i v I. r , .r t i t i , t i, : ( I t o( t I l mI e r ( ,t i r v i n t h t, ' .t , .i w a t e r w e r e ( M 1 !(1 1 p p ' -j

'r-rh pp,, (per.rg,) . ,l)pct it lv. I 'xper iment I t h

• ..-..... -. ....... v.-.-...-.., :..- -
.

.

.' h t 'it 1ul v !), t 1 C V! 1' - I I r V II, t fi, m r ; ' tu t..- f

St h. '" cii r 1' 1ird t t I i, I I r %I wt, re t it ,id t '7-1 t! k, t 7 Vt-,v.

I t e c in t i k c i mev t me I (u I- T T v t;'iw I ti I r i ) ,'A-t-p 'd <s. ; t "

re p trIt-(I that a o oud ni-gat i vc rt r lIt 1ii r I I t. x t t_w i1Ih 

tie( ii 'tlii elltrit Br , C i meit tal'. Iv II: i rtlir ii! te d'r d v n. I , ,, iir, % ,

titnlr , t lit corr c at it n n 1 Fi'ulre I lg Y .)g-- . " 4 ,'g X the

b 1i1nc01tit rIt i On l actor t or .r i popIlat ion dvns itv; tv , ind i vti(I ,i p lit re

exper iment I g roup) and I(or a dens i tv < I . i iv vi idua I per it re exper imerit .' group were estimated. The bloconcentrat for factor for tile experimerit I gruiu wits about 18 ,()()() times, and the hiocorcentration tactor !(or tie

experiment .' group was about i ,(0()0 ) time-. fy using tile biocuncentrat .on

factor obtained from the -st imat Ion and the concentrat inn of met hy lmercurytaken into the copepods, it is possible to estimate the concentration of dissolved methivImercurv in the seawater. obtained results were as follows. In

the experiment I group, the concentration of dissolved methylmercury in the

seawater was 0)00012 ppb. This concentration corresponds with 1/100 ofmethylmercurv contents in the sediment. In the experiment 2 group, the concentration of dissolved methylmercury in the seawater was 0.00026 ppb. This .

concentration corresponds with 1/6 of methylmercury contents in the sediment.

xl04

100 e

X

.:'4

10 Mercury

0 concentration c- 0 in seawater

x MMC 0.5 ppb •

r

oMC 0.3 ppb

0

log Y 6.4530 - 0.6014 -log X

(r * -0.9310) a, MMC 0.1 ppb

a MMC 0.05 ppb

-I,-. %I

10 100 1000 %

Population density (ind./:)

Figure 1. Correlation between bioconcentration ,)J methylmercury (14MM) and density of .

%

- *.*~ ~ * - -.-.-..-
i e pt, p Lment 'it wai- expected thit metliv lmercurv tormation f ror

i no -,inIc mercur V in the sediments exis;ted, and that the concentraition o! ","p

met1b\ylrrer irv in the copepods increased by 0. 17 ppm (dry weight 11asis)

howe\'r, the, estimation method explained in this paper suggested that the

,,ont ent ,I inc reaIed methIlimercuirv in the copepods was brought about by the _

in: t ii c,ntent; ot methv!mercurv in the sediments. It was considered that

meth\ lmerc.irv and inlrgan ic mercury in the sediments dissolved into the seawiatur wi th sun Iight irradiation.

(;oN(:I.l'S I ONS

M1arine copepods were reared in seawater containing sediment with methylmercury and inorganic mercury on the particles. Then dissolved methylmercury

concentration in the seawater was estimated by using the correlation between

the bioconcentration factor of methylmercury and the population density of".

copepods and by using methylmercury concentration in the copepods. From the

experiments, it was estimated that short-term sunlight irradiation and shortterm exposure of aerobic condition did not form methylmercury from inorganic

mercury in the sediments, but dissolved methylmercury and inorganic mercury

into the seawater from the sediments.

REFERENCES

Fujiki, M., and Tajima, S. 1974. "Studies on the Transformation to Methyl

Mercury from Inorganic Mercury in the Muds in Minamata Bay," J. Kumamoto Med.

Soc., Vol 48, pp 117-123.

Fujiki, M., and Tajima, S. 1976. "Studies on the Transformation to Methyl

Mercury from Inorganic Mercury in the Environment (2nd Report), Transformrrion

to Methyl Mercury from Mercuric Sulfide," Kankyo Hoken Report, No 37, pp 6-9. %'."

Hirota, R., Asada, J., Tajima, S., and Fujiki, M. 1982. "Accumulation of %.-'.

Mercury by the Marine Copepod Acartia clausi," Bulletin of the Japanese ,

Society of Scientific Fisheries, Vol 49, pp 1249-1251.

"O*

< .p

,,.... -
WATF Q 'ALITY MANIPI'1ATIBNS IN A E "TR(i'Hi(c IMPOI'N1 5>tN .-..

John W. Barko, Andrew k. Klemer, Dwilette (;. McFarland, Pox I.. Chen

Environmental laboratorv

Waterways Experiment Station

Vicksburg, Mississippi il180

ABSTRACT

Poor water quality in Eau (;alle reservoir, located in west-central Wisconsin, has been associated

historically with an overabundance of nuisance planktonic algae (phvtoplankton) during the summer months.

In an attempt to improve water quality, a variety of

experiments was conducted over a 2-year period in

large (10 m diameter) enclosed water columns. Spe- r*,e

cifi,, objectives of these experiments were to reduce

phytoplankton standing crop and to promote favorable

changes in species composition, i.e., away from nuisance algae (cyanophytes and dinoflagellates) toward

more desirable algae (diatoms and chlorophytes). Experimental treatments, implemented singly and in combination, included destratification by mixing, addi- I'

tion of soluble silica, sediment sealing with sand,

and precipitation of phosphorus with block aluminum

sulfate. Mixing, alone or in combination with silica

addition, extended the presence of vernal diatom populations into the summer in one investigation. In contrast, addition of silica to the water column without

mixing had no effect on diatom production. In general, mixing stimulated phytoplankton production by

increasing phosphorus availability. However, phosphorus inactivation with block aluminum sulfate suspended in the water was sufficient to overcome this

effect. Individual effects of phosphorus precipitation and sediment sealing were similar; both decreased

phytoplankton standing crop in association with decreased total phosphorus concentrations. Since most

of the phosphorus contributed to the phytoplankton in

Fau Galle reservoir derives from the sediment, complexation of sediment phosphorus is recommended to .-

improve water quality.

I NTRO [t'CT I ON

Algae ,re an essential component oi aquatic ecosvqt em,. These orginf-ms

ar rfsponsie tor the svnt hesis o, organic materials, pr, vi ding much of both

the organic structure and ener-x upon whi oh other c emponnts , aq(ati ic .-.

%- %

_4.- -~ & .A. ~ J Z. .. .". 'u
C O~ -~ .•V 1 ..•t 

.:ri,. e ,! ,, -u rent:, ,,' "1c t! ti. C" i ! v ' t .. . , .• -, ."

~, , 1 ,~ .

rt.,,'.. irs s ~. ;,, t in, cx s --,i e l[: , i.. .....- . "" .. .. -,. t' I t

te re di I toIr x-r , t i 11 1 t, t C and i t rt-szt ' I" 1 ,. r , " t t 7 -- t I"

I C C' t it r I' e n1 ), t I-, i ' t' I it IIII , to P 0n .- .t.t' -;u, t ,

I e' t, re i I I",la te aI I I ta I n'V i, 1. r \ v m, i not I "ut r ilt 'II Ad >1.,1

1-p Ike ;Ippro . lies to :l mali manageme nt, perhaps i rVlvin chIanges in ',p5

)T, p,-i t in (i.e. , IrOw nutlisance species to mort, desir.alle specie ttjil'% ' nit-d 

he d evelop(ed . 7owaird t h i end we have condutc te e en c 1I osut r e cx perimen t s iii

.(ttt'7pts to manipulate hoth the standing crop and species compositi.,' ,i tie

plainktonic algae (phytopiankton) of 1-IatGal le reservoir, A classicalIv eltrophlic system located in west-central Wisconsin. Results of these experiment,,

are reported here for initial consideration in formuliating a management plan"

specific to algal problems in Fau Galle.

SITE DESCRIPTION

Eau Galle reservoir is a small (0.6 km 2 ), shallow (3-m mean depth), moderatelv alkaline (2-4 meq 1-1) dimictic impoundment. It has one major and two

minor tributaries, which deliver nutrients from cattle lots and associated

agricultural lands, and a single outflow, which receives water from both surface and bottom withdrawal points. Major water exchange and external nutrient

loading occur during spring thaw, when as much as half of the reservoir volume

is replaced within a period of several days. Throughout the remainder of the

year, hydraulic exchange is relatively minor. During the summer, bottom withdrawal of water in combination with wind-driven mixing processes promote hypo- %

limnetic warming (,l15' C), which accelerates mineralization rates and enhances

nutrient cycling. Historically, algal blooms in Eau Galle reservoir have been

severe.

The seasonal succession of phytoplankton in Eau Galle is fundamentally

similar to that described for many temperate eutrophic lakes (Wetzel 1983).

Eau Galle is dominated by diatoms during spring and fall periods of destratification and codominated by cyanophytes (blue-green algae) and dinoflagellates

during summer stratification. Three species (G7 >, :'J, .4-n7, w: .... , run.,

(L.) Ralfs, and ',,t,, e- ... ., (O.F.M.)

Schrank) typically contribute 50 percent or more of total annual phvtoplankton

bioma s. Depressed epilimnetic silica concentrations occur during spring and

fall periods<, of diatom growth. The development of nitrogen-fix:ing cvanophyte

popuiations during the -u mmer reflects reduced inorganic initrogen a-trailibilitv. The combirti,,n of changes in thermal conditions, water co1Umn.

%W. % "
S t. '."It -

nI

c l t tr i r' t.ors I ,iii tc ro 17", 1' t

11 ( e11d e ( t o e TIC u kI I t ? d i ~ . .I-

,iI g* it the exp i\'i ;' ,. ! L v l Ilk)I 

FAB! F: I LAt ? x .E. .

Column Number , -

3

.4

* Si] ica was appl ied cont i'u, Iv I . ". 

2) g Sit)) per cubic r'tre per mwitl.

The -Pr inc I pi I t r it c' ,mF t 1,,

* C A .' 111, 1 ~ l11( P1 1 W . ' -li r~' :. n j' ,t d p : h , t . , ; "',

P2 . , -- -%. . ". . -.... ." " . , . ,
,_ % -._

I H I : IKNTAI. . TREATMENTS IN 1984 -

Treatment *-

Sediment Seal* + Mixed

Alum** + Mixed

Sediment Seal

Alum

. !-"-o et" th ' cm of washed silica sand. Total mass added

.,ercent) was added in block form. Blocks were continkeep p ice with dissolution rate.

S:te,'rted sampl.s (0-3 m) were taken from each enclosed water

ptn water. Separate aliquots of each sample were analyzed for

rphll a content corrected for phaeopigments (American Public

It i0T,, IAi'HA) 1l480), total phosphorus, total soluble phosphorus,

.r u, totai soluble nitrogen (Raveh and Avnimelch 1979, for N and

~:~~td 41ica (automated molybdosilicate method, APRA 1980).

, a . counts and cell volume determinations were fixed in Lugol's

:-n:pes of 1l0 to 50 ml were transferred to sedimentation chambers

S- eV with a Wild M-40 inverted microscope following the technique of '.-.]

and leCren (1958). Cell volume determinations were made in

. it t technicues described by Barko et al. (1984).

RESULTS

__ , .on Response in 1983

investigation had three phases. During the first phase (May 9

columns ; l and #2 were mixed continuously, and silica was added

Ird ;- (Table 1). Silica enrichment continued through the

1,-:t 'line 13 to Julv 19), but mixing was intermittent due to stormt p.,.r a ilures on three occasions: June 13, June 28-29, and July 3-6.

S",- tK, : l period (,Julv 19 to August 16), a secondary treatment (addi-

.i l, i jm) was implemented in column #1, silica enrichment continued

. iTd tuntil ulv, 22, and mixing in columns #1 and #2 until

:,-i '1nt.'n 1)i omass and commun ity compos it ion varied among s tudy

';,atoms and cryptophvtes were most abundant during the .. . . *'et ,, c t inn. Diatom biomass during the first period was

, -o . I tmn,- than in either the unmixed columns or the

, rvptoplito hiomas.s was greatest in the unmixed

S.. iinvestigat ion, total phvtoplankton biomass

-pen wito r and in all co I umns except 1.2.

was due almost entirely to the develop- " I m t blooms as populations of diatoms anld

." %'
p .

OPEN WATER CONTROL

COLUMN #4

70-

60,

50 F

40-

30 -

20-

10- %

0. ...

SILICA SILICA + MIXED

COLUMN #3 COLUMN #1

C-%,

E 70,

60- -

50-

u540-

0 30-

20-

10- 

-

0 o ... ..-. ,. n 1 MAY 1 JUN 1 JUL 1 AUG 1 SEP

DATE IN 1983

MIXED ALGAL GROUP SYMBOLS COLUMN #2 MISCELLANEtli I CHLOROPHYTA CPYRRHOPHYTA - EUGLENOPHYTA

70 CHRYSOPHYTA 8ACILLARIOPHYTA 60" CRYPTOPHYTA CYANOPHYTA

50

40

30- 20 ""-

0 .........

I MAY I JUN 1 JUL 1 AUG 1 SEP

DATE IN 1983 ,%.".ll

1. (o tributions of ",arious algal groups (taxonomic g

divisions) to total phvtoplankton biomass in the

Ptn water and in experimentallv enclosed water

,r: .,rir the simriner of 19 83

r I - T: t hr. T7.1 t i-irl i T' t h# t- -

r I ... . ' th " t prp v, <we',.r ,rt ,n , I diu , bi ma :', 6
Phvtoplankton Response in 1984

The 1q84 investigation was continuous, with no interruptions in mixing. -

Phytoplankton biomass in 1984, with the exception of that in column #1, was

about half the biomass in 1983 (contrast Figures I and 2). Greater biomass in

column #1 than elsewhere was due solely to the development of a massive chlorophyte population (principally the filamentous species, M,!bcotia) during mid

through late summer (Figure 2).

,. '4

OPEN WATER ALUM

COLUMN #4

40'

30

20-

10,

SEDIMENT SEAL ALUM + MIXED

COLUMN #3 COLUMN #2 ," .

C 40-

,.":E 3 0 -"

' 2 0 - e : . '

~10~

A JUN I JUL I AUG I SEP

DATE IN 1984

SEDIMENT SEAL + MIXED

COLUMN #1

40- ' , ALGAL GROUP SYMBO.LS

30 - MI'ILANIGU 1111 CNLI0 PH 1TA

PYARMOPN YTA IU t [ 10 P"Y 1A

20 CNAYSOP'VYIA SOACIUIARIOPHV'A

CPYPIOPN A CYANOPEYTA

10 v °- ,

JON I JUL I AUG I SEP

DATE IN 1984

.,

! I I ~ '! i -" ' III i n , II , "-"- d Id I I iI ,= .. ..
Jinol lag lates peaked in tile open water and in all columns except 0,

dUr ri i Tune o 01 , apprnx fmate I v I month earl ier than in the previou, year

These peaks corresponded with the waning', of re lat ive lv minor d iatom and

chrvsophvte popul at ions. During mid-JlulV cvanophvtes assumed dominance over

dinotlagellates. hiomass in all columns except #1I at that time was exceptionallv low, but comparable to that in the open water. Throughout the

remainder of the study, cyanophytes continued to dominate all columns and the

open water. Dominance in column #1, however, was shared by chlorophytes.

Physical and Chemical

Effects on Phytoplankton

Additions of silica to the water column in 1983 significantly increased

silica concentrations, up to threefold greater than in the open water, but

this treatment alone had no effect on diatom biomass. Diatom production was

stimulated by addition of silica in combination with mixing (column #1), but

to a lesser extent than mixing alone. Dissolved SiO concentrations in 1984

2

increased progressively from <3 mg k-1 to 9 mg k-1 throughout the study, did

not vary among treatment columns or the open water, and were unrelated to

diatom abundance. %

Total nitrogen concentrations were essentially unaffected by the various

treatments in either investigation. In contrast, total phosphorus was higher

and ratios of total nitrogen to total phosphorus were lower in mixed columns

and the open water than in unmixed columns, particularly in 1984 (Figure 3).

Part of this effect was due to reductions in phosphorus associated with sediment sealing (1984, column #3) and addition of alum (1984, column #4). How- ,

ever, the same trend in 1983 with no experimental reductions in phosphorus

indicates that mixing did elevate total phosphorus levels. In both investigations there were strong associations between high total phosphorus concentrations, low nitrogen-to-phosphorus ratios, and high cyanophyte biomass.

Conversely, low total phosphorus and high ratios of total nitrogen to total

phosphorus were associated with high dinoflagellate biomass.

Concentrations of total phosphorus were significantly correlated positively with total phytoplankton biomass (r > 0.55, p < 0.01) and negatively Z

with Secchi depth (r < -0.73, p < 0.01) during both study years. Secchi depth

decreased in these investigations proportionately with increasing phytoplankton biomass, and was further depressed periodically in mixed columns due to

turbidity caused by sediment resuspension. Mixing increased the rate of phosphorus flux from sediment interstitial water into the overlying water

(Table 3). Notably, however, sediment sealing reduced the rate of phosphorus

flux to less than half that determined under unsealed conditions. All experimental water columns remained aerobic from surface to sediment surface; thus,

di e rences in phosphorus flux were probably not determined hy differences in ..

re.dx pot,.7 t iaI. -I•

Oit , it i-c W.I. I ,t t e if . t 

4 . t ir 'i ) t r I' (if t r

P"~I *'S ..... t 1.r 1 t 11., tI.t ho. : * . 94 4-4.'. 4 -

_it

%

%
0.04-

0.02

0.07-

0.06

0

20--

10

1~~~~~ 41AG841SP8~ ~~ JU 41JL 

% SMPLNG AT40r

TREATMENT

ALU ALM+MIE30 OPE WATE LI

SIIC + IE

Fiue 1 1oaIpophrs ClIcneta in., n a iso oa

20rgnt oa hshou nteoe ae d I nd encose i re per waer i e nta olums drin th

,imrir of 98,
TABLF 1. FI.I'X RAIES (AT I C) I)F flRTHIPHOSPHAIL F-IM SHI)IMFLT5 - I Till I.

S FEI(TRO EXPERIMENIAI, lT'MNS URf)('TN'; ILE 1984 INVESTI ;ATI(ON

-2 -1 ] .

Treatment Condition Flux Rate, mgm day *

Sediment Sealed 14.4

Sediment Sealed + Mixed 20.6

Sediment Unsealed 32.9

Calculated using a modification of Fick's equation from vertical profiles of

orthophosphate concentration measured in sediments.

open water as well as in the unmixed columns, diatoms began declining in mid- *%

May as water column stability (i.e., resistance to mixing) increased. .%.

Diatoms, because they are relatively dense and lack the ability to maintain

position within the water column, are particularly disadvantaged in hydrau-. ..w

lically stable environments (Hutchinson 1967). Destratification by mixing in

1983 facilitated the extension of spring diatom populations into the summer,

but this effect was not enhanced by silica additions. Thus diatom population

dynamics in Eau Galle appear to be more responsive to hydraulic conditions

than to the availability of silica.

Unlike conditions in 1983, experiments in 1984 were initiated a full

month following the collapse of vernal diatom populations (Barko, unpublished), and in contrast to the previous year's results, diatom production in

1984 was not encouraged by mixing. Apparently, mixing in Eau Galle is only

cffective in maintaining vernal diatom populations when initiated prior to

dirtom collapse (see also Nicholls, Kennedy, and Hammett 1980).

We were partially successful in maintaining preferred algae (diatoms) by

mixing, but not at the expense of nuisance algae (cyanophytes and dinoflagellates). In general the growth of cyanophytes was stimulated by mixing, while

that of dinoflagellates was either depressed somewhat or unaffected under the

same conditions. The growth of chlorophytes, principally filamentous Mougeotia, which is not a desirable species, was also stimulated under some circumstances by mixing--in combination with alum treatment in 1983 and sediment r---

sealing in 1984. Chlorophytes were essentially absent from columns in which

mixing was implemented alone. ,'

Trimbee and Harris (1984) suggested that the most notable effect of

periodic natural mixing episodes on phytoplankton was a shift in dominance

from nonnitrogen-fixing to nitrogen-fixing species. In our investigations

nitrogen-fixing cyanophytes dominated at times under both mixed and unmixed

conditions, but were generally more abundant in mixed columns. The most prominent cyanophyte taxa In mixed columns were il)(21'hICK and Aphan;;om :.on speties, both of which readily fix nitrogen. Nitrogen fixation has been viewed

• a ri.*pons;fe to ;to icliomttrtc imhal ance between nitrogen .und phosphorus

ivli);ih I i tv 1S l ( i ter ci ). Accordin I,'-, r l/ativeIv low rat i,s, of tot.il

1 r1 .n to tt t. I h,phr, (TI /' l), a,, in ,,,r mij d c'o ,Imns, t end to favor

%% %

.,'-t

* - ,* .. - "4 
Dinot lagel lates, principaly 1 , .'; ' were dominaint in the .ah;,'lz e ()f

mixing during mid through late summer In 1981. Hwever, in 19 '

, mlx in, hidi nJ* _

obvious effect on dinof lagellateS, which a'C hieVd dol hCl mi iltl11e i a l (,,1M n and

in the open water during the earl%, summer. An intere,tIng (hbrv.1t ion alpp] icable to both years ()f invest igat ion is that dinof lagel lates genfe'r.i v fared

best where c%.anophvtes fared poorest. On the whOle, t18 Was d min itd t , IlV%

d nof lage I lates while in 1984 cvanophytes dominated. There mav he in anta('-

nistic interact ion that accounts for the apparent inverse reiati 4niship between

dinoflagellate and cyanophvte populat ion deve lopment ( Vance I 9t,') ; Iot tniLindgren and Ekbohm l'4 7 9; and NIchol Is, Kennedy, and H.ammet t I 4() , h,,t ia'; a I

mechanisms have not been satisfactorily explained. ,

In general, the production of phvtoplankton biomass was stimulated by '"

mixing, and this effect was most pronounced in 1983. We attribute this response to increased phosphorus availabilitv caused by sediment restispension

and enhanced phosphorus diffusion from sediments under mixed conditions. Notably, phosphorus inactivation with block aluminum sulfate under these conditions was sufficient to overcome stimulated biomass production. Although

these results are strictly applicable only to relatively shallow regions (less

than about 3 m) of Eau Galle, they do underscore the important influence of

sediments or phosphorus availability and resultant phytoplankton production.

The sediment is the major source of phosphorus in Eau Galle during the

summer months, when inflows account for no more than a few percent of the

total phosphorus budget (James, Kennedy, and Gaugush 1985). During this

period phosphorus in concentrations >2,000 wg Z-1 in the anoxic hypolimnion is

made available to the phytoplankton by periodic weather-related mixing events

(Gaugush 1984). Mixing in Eau Galle is facilitated by relatively low water

column stability due to the effects of bottom withdrawal of water on the .-

thermal regime. Similar effects of weather-induced mixing on phosphorus

dynamics have been reported for Shagawa Lake, Minnesota, another relatively

shallow basin located within the same climatic setting as Eau Galle (Stauffer

and Armstrong 1984).

Sediment sealing with sand in the absence of mixing was fairly effective

in reducing total phosphorus release from sediments under ambient aerobic

conditions, but would probably have had a lesser effect under anaerobic conditions due to enhanced phosphorus availability at low redox potentials

(Wetzel 1983, p 261). Mixing largely negated the effect of sediment sealing

on phosphorus release, izidicating that the advantage gained by increasing the

diffusion distance between sediment surface and overlying water was minor.

Addition of alum in the 1984 investigation decreased total phosphorus concentrations in an unmixed water column, and thus was effective in precipitating a

portion of the phosphorus released from underlying sediment.

Improved water quality in Eau Galle will require a reduction in phosphorus release from sediments during the summer months. We propose to do so

by administering alum directly onto the sediment surface within the profundal

region (i.e., >3-m depth) according to procedures described in Kennedy and

Cooke (1982). The advantage to using alum as opposed to an inert sediment

seal is that the former selectively complexes phosphorus in chemical forms

that are unaffected by changes in redox potential. Prerequisite to the successful application of this approach is the knowledge that internal loading of

phosphorus from sediments dominates the midsummer phosphorus budget. Alum

".- .

173 "wv

. % " * A- % .. . .P_. .
.11 111 tfit- t A ! "r ) i 1 - , ,i l . " ;

iV ill t' i , c, 'tg . \' !I ttT t Iii 1 - ? iIT

r 'I 7i t . lw I . ( I I.r j . '111d g 7 1101 1 ( 1 'ul h w 7Ip wk, I f. Ji , V' I tl I . 7 . 7

t. In

.\," r i(,ItI i I ii I le i It h As siw i t i7~ Ir 18). .St rldi ~rd Me t ho.iI~ or t he f X;I1 'T,I -

tn- oit t: tr e -In d .'a't cwat er. I 5thI ed. N New Yo r k New Yo rk, VA.

fir k, W1 ba. Kt es, 1). I th i n,1 .1, Hlennlington, S M, Arid FIa rI-In d(1 ). 1 98 "Se,,uona I Growth and Conunni t v ('ompos i t i on ol I 'livtp.,likton in aI Futrophic k'.scons in Impoundment,'' Journal ot Freshwvater Fc)o ugv

VoI ,No., pp 519-)13.

Cooke , C 1). and Kennedy, R. H. 1981. "Precipitation and Inactivwation of

Phosphorus as a Lake Restoration Technique," EPA-600/3-8l-0l 2, Corvallis

E-nvironmental Research Laboratory, US Environmental Protection Agency,

Corvallis, Oreg. , LISA.

iDottne-lindgren A., and Ekbohm, G. 1975. "Cerzt-,iurr hinrdir,,Ila in Lake

Erken: Horizontal Distribution and Form Variation," Internationale Revue der

gesamten Hydrobiologie, Vol 60, pp 115-144.

Caugush, R. F. 1984. "Mixing Events in Eau Calle L~ake," L~ake and Reservoir

Management, Proceedings of the Third Annual Conference, North American Lake

Management Society, US Environmental Protection Agency, Washington, DC, USA,

pp 286-291.

Henning, M., and Kohl, J.-C. 1981. "Toxic Blue-Green Algae Water Blooms Found

in Some Lakes in the German Democratic Republic," Internationale Revue der

gesamten Hydrobiologie, Vol 66, No. 4, pp 553-561. ".'

Hutchinson, C. F. 1967. A Treatise on Limnology, II, Introduction to L~ake

Biology and the limnoplankton, Wiley, New York, USA.%

James, W. F., Kennedy, R. H., and Caugush, R. F. 1985. In press. "H-ypolimnetic Phosphorus Dynamics in Eau Calle L~ake, Wisconsin," l~imnological Studies

at Fail Galle, Wisconsin, Technical Report, R. H1. Kennedy, ed., US Army

Engineer Waterways Experiment Station, Vicksburg, Miss., USA. .

Kennedy, R. 11., and Cooke, G. D. 1982. "Control of L~ake Phosphorus with

Aluiminum Sulfate: lDose Determination and Application Techniques," Water

Resources Burl letin, Vol 18, No. 3, pp 389-395.
Ii:

t , t .

, 

Vt.l, d t. Iu c!T p "l'i p t iili ,i t' o 'ti Ivti c tlll li L l ilt P ti'i l ii !> , i I he I t t '.. ,o t i h tit u lnd A liv '

ii' t4

, .i II j,. I. n111 i. t1r1(l '"'hI . l ve, r t td M i i ,

op t t , I , ji t A] '. %1N1uttri .i nd t t St,l t iFl t a i h.i ;i , t I ima TIt -

t i t, n , ., H t tdI , wh ia Va , I 1 I Ii I i - I .

.i~ c. h 11, , 1' l 1' + , ii<v .]i)4f H..1mitle t t , . I ,';.i I "A F " f F- I I in Hel t.,

St f w I lit-, t I .;o ."_ . . . . . .. , V I a f t ) , on pp t -I 

ritt i , '. i , liii a ut en . I I1 . I I. A low i-nerg%,v lake D)etrat i I i ,

r l_ - t t! I. t if \it' r i Slt , t uit I itu r a I vr, i, ttvr , Voli Ifin, No. ',

k,veh, A. .ii ,\v ni mt-lI Y. 19 7 "Total ' Nitroyen Analysis in Water, ,iI

-ind P tlant . 1.it,,ri.il wi th !'erstul Iit t i lx at ion ," Water Res,-earch , Vol 1 3,%

Ichiindler, I'. 1B7'. ' F. lution o t Phosphorus l.imitatiion in lakes:

Natural Mec'hliTii ;ins tompensate for Deficiencies of Nitrogen and Carbon in

utrophiod l ake<" Science, Vol 195, pp 26)-Th2

Smith, V. H. 1 1 I. "low Nitrogen to Phosphorus Ratios Favor Dominance by

Blue-;reen Algae in Lake Phytoplankton," Science, Vol 221 , pp 669-671.

Stauffer, R. F., and Armstrong, 1). E. 1984. "Lake Mixing and Its Relationship to Fpilimnettc Phosphorus in Shagawa Lake, Minnesota," Canadian

Journal of Fisheries and Aquatic Sciences, Vol 41, pp 57-69.

Trimbee, A. B., and Harris, G. P. 1984. "Phytoplankton Population Dynamics

of a Small Reservoir: Effect of Intermittent Mixing on Phytoplankton Succession

and the Growth 'P.

of llue-Green Algae," Journal of Plankton Research, Vol 4,

pp 699-713.

Vance, B. D. 1965. "Composition and Succession of Cyanophycean Water

Blooms," Journal of Phycology, Vol 1, pp 81-86.

Wetzel, R. G. 1983. Limnology, W. B. Saunders, Philadelphia, Pa., USA.

175 ".

I b

% % -'7
UWVn V_

FI EFFE 'S M. ,F P1MFNT IN F1, St'RVIVAI , ()F" MOS M I XPDS DI) t)R(;ANI .\

M. H. Salazar, S. M. Salaz,r %

ETnvironmental .,ciences Division %

Naval Ocean ,.vstems Center

San Diego, (alilornia I .'.'

ABSTRACT(.SA l)-dav flow-through toxicity test was conducted :%

by exposing mvsids (..c'rtt,'lo ,:'a" r u t:) to organotin .* "

antifouling (AF) leachates. A paired design with and

without sediment was used to determine if sediment afecots the survival of mvs.ids exposed to organotin AF

leachates. Since the Navy is considering a fleetwide

conversion from copper-based AF coatings, it is studying the potential environmental impact of organotins

and their effect on the dredging permit proenp,

Eighteen-day-old mysids were exposed to

tributyltin (TBT) concentrations averaging 0.60 ppb

for 10 days in the presence and absence of sediment.

TBT concentrations in tanks with and without sediment

ranged from 0.41 to 0.80 ppb and 0.54 to 0.78 ppb,

respectively. Sediment did not accumulate detectable

quantities of TBT during 31 days of exposure.

Sediment and toxicant both affect the survival of

mysids. Sediment became a statistically significant

factor in the survival of mysids by day 7 and continued to be a factor until the end of the experiment.

Mysids exposed to TBT exhibited significantly higher

survival in tanks with sediment than in tanks without

sediment. A significant decline in survival in the

TBT tanks without sediment was observed 2 days before

such a decline in the TBT tanks with sediment. The

TBT toxicant became a significant deleterious factor

by day 8. After 10 days control survival was 100 percent with sediment and 95 percent without sediment;

TBT treatment survival was 46 percent with sediment

and 30 percent without sediment.

I NTRODUCTI ON

AF coatings for ship hulls contain toxic compounds such as copper and

organotin which leach out of the coating matrix to inhibit attachment of

marine organisms. These toxicants enter the water column and a significant

portion is then adsorbed by the sediment. Since the Navy is considering a

1 70

• .- ..9

%" % -N 

V ~ ~ vV' .~%J%\V.V.. V . ,s
,, 'v rsi ,r rom copper to organot in-based A l coat ings, it is studvinr' the

p ete i. ' ,rivironmerit I impact that might be attributed t, I leetwide '*mplementt ') t i org ,,t in-tbased Al coatings. In a related prog ram the Navv is a Iso - tl ','I T , tht' p~t On t il I eV! fect otf organt, tti~s (in d redg ing and d isposal, and thle._. ,

htdg i I pet I prs 0..

ed i ment dredging" is a ma jor and cont inu ing Navy requ I rement which is

TrI t -ippr olh ing I 'i mill Ion cu cd/vear. With a pro jected introduction of %

I ,.(p Ir,a t , ,e I s and a potent ial 6(00-ship Navv by the year 2(00, thiis burden %

w i , i r rv,,se. Ant icipating thi s potent in problem, the Navv has (level-

,,t,,'e a pr,,r t to expedite Navv dredging by opt imizing the dredging permIt

,,s .As part of this program, a Memorandum of Agreement (MOA) with the

A rm\ orp o' Engineers (IF) has been proposed• As part o I this program a %

* <,i,,,sirL w.P. c,,nducted on organotin-contaminated ediment Irom San liego Bay

SI j, a Ir '111d -qa aza r l -8 .".

Alth ,!h some commercial fleets and private owners currently use

* ,rg.4nol, :i-l isod AF coat ings, the behavior of organot in compounds In the marine

e environment is not clearlV understood. To date there are no regulatory cri-

*, terla for the disposal of organotin-contaminated sediments. Since there are

potential environmental problems associated with organotin AF coatings, the

' 'Iv " i' sp , .. .. d a research program over the last 5 years to study the fate

aind effects ot organotins in the marine environmpnt. Much of this time was

spent developing techniques for accurate measurement of organotins in sea-

- water, sediment, and tissues. Concurrently a number of programs were devel-

* oped to measure the toxicity of organotins.

The principal toxicant in organotin coatings is TBT either in unbound

mixtures or in controlled release polymers. The TBT is released from the

coating through hydrolysis to marine waters. It is generally accepted that

the TBT cation is the toxic component and the anion is not a factor in its

toxicity. TBT degradation products are less toxic than the parent compound.

Our work has shown that TBTs are nearly an order of magnitude more toxic than

dibutyltins and two orders of magnitude more toxic than monobutyltins (Salazar

and Salazar 1985). Smith (1979) has reported similar results. Smith also

reports that the most important use of TBT oxide is in marine AF paints. For

these reasons we have conducted almost all toxicity tests with the TBT form.

Only recently have the most meaningful results been produced due to refinements in both the biological assessments and analytical techniques. Ira,

Our early work, as well as the work of others, has shown that sensitive

- marine species exhibit significant mortality at TBT concentrations below

I ppb. During the past year we have measured TBT concentrations in seawater

as high as 0.93 ppb in an enclosed yacht basin in San Diego Bay (Valkirs

et al. 1985a). This concentration exceeds the 0.60 ppb TBT reported to cause

effects on sensitive marine organisms like copepodp and mysids in laboratory

tests (U'Ren 1983; and Valkirs, Davidson, and Seligman 1985). To assess

future dredging problems, we conducted a standard dredged material bioassay

*~ 4ith organotin-contaminated sediment from an area in San Diego Bay where we

Shad previously measured the highest concentration of TBT in sediment. The

results from that study indicate organotins bound to and released from -

sediments were not as toxic as anticipated. We were surprised to find no

%

177

I--

"" " "" ... " " " " " " C. " " , ',-",-", . . .- . , , . : €*' .C", .".,"- .. -a- - -"" , _'". m -a. *f "' *.** *. C.. - . . . ' . .~ ~ .. C . d 
sta t i St i cal. 1 ifhj~n t1ict ttl~ Wn 1t i g~j h I c~etr

t het sed imt. ir jte v(onc klt Vait ions i1 thault test '11 ,r .I cie d th 11

p)rod(Iuci I ug sgn iI I L'.111t TTO r t A I i t Cs in ot hVr t uld i e

lIi t. - Li1 1tj ollsh i p1 h etwen IISecd imenTlt an 11 i! t (x it t o T.Vs w, vI . iXI r T; t

inl more detai 1 dolring the pIresent stuld:,. :hk-pirp-.t this wi4t was- t. dutevr in l i I t le suiir ia I t m v s iIs expos )-;ed( to Walinot il N I Iv l I~ ic 1,1ts Ii 

te cte t,(11 the p)r esen ce t sedI iment.

M ETH 1) S A N: MATFl:k I A

Y i r n en1t al I Ies I kn

Fo)ur exper imentalI cond it ions were used to te'st the I0(t ec Of seVi imett

aInd (Irganot in I e~ichiate (on rn's id surv ivalI They, were: clecan seawaiter on] v

((:SO), CleanI T seawater wi th sedo iment ((SS) TBT I eachate, seawa ter o)n Iv

(TBT-SOi) , and TWI I eaichate se.,wa te r and sedimfent (TBT-S";) . T1i e f i r-s t t wo

cond it ions, CSOi and ('SS, were des igned as controls. M~s id survivall data for

treatments were compared with controls with a two-way analyvsi s of variance

(AIN0V A (F Igu re ).The variables, compared were toxicant ("control" versus

organot in exposures") and substrate ("seawater" versus "sedimeInt") . The * *

ANV also permitted testing for signiticant interaction o1 1131 and sediment

on mvsid survival. The conditions tested can be summarized by the following %

hypotheses:

H 1: Organot ins have no effect on mysid survival. 0

H 02: Sediment has no effect on mysid survival.

H 3: Organotins and sediment do not interact to affect mysid survival.

0

To test the hypothesis that sediment increases the survival of mysids

exposed to organotin, the experimental design consisted of monitoring the survival of mysids exposed to TBT-contaminated seawater with and without sediment

present. Five replicate tanks were prepared for each test condition with

20 mysids per replicate. A total of 20 test tanks was used, ten with sediment

and 10 without. The test was run for 10 days to duplicate conditions

recommended in the Implementation Manual (Environmental Protection Agency

(EPA)/CE 1977) for the solid-phase portion of the standard dredged material

bioassay and in the bioassay conducted with organotin-contaminated sedimentg

(Salazar and Salazar 1984). ~'~

TOXICANT

NO TOT TBT

S

u CLEAN SEA WATER QNLY TBT lEA WATER

B NO SEDIMENT QNLY

S(CSO) (TOT-SO)

T .

R .QLEANIEAWATER A 13] SEAWATER A A SEDIMENT SlEDIMENT SEDIMENT

T (CSS) (TOT-SS)

Figure 1.Experimental design

178

%9
J..

, t W 'I "1 I ' I !(Lt t 111 t0 ,' .i w V t ', lit II t t

-..

1ti c . " ti' .

',, I t t t t ,t W ,l II -

it t ArI li Ted ti ON I t i prtet tlit k t' .I!I L l ,.t V-t- - Il ot,! ! io ,,m i;u~r a c .;,oopl~int ,I,,: M\'iv q < I t. (,!I thelt> .p")? e spt', :,t., . ' "

I -i0' i! iLredlget 'l l,itt rjil hjois ( P-A '( f, I Q i rt~t,rl, thlt I,' i , , -

s red v Imprtant ei,1 "gh to be rujIl red for both ti1e 1 iqui , p.irt i 1,! tt pha,t.

Aitd t h solid ph,i se port io s Io t lie sta ndard )bloassi'..

Y ids were co I ected ,n I N,1irc 1 1 5 just uit side the mouth of Sir Ii i-o

Ray wi th in a )(M-m raldius of the laboratory" seawater intake. They were collected in the surface kelp cainopv with buckets and returned to the laboratorv

holding system. These mvsids were maintained in flow-through rearing tanks.

Released iuveniles were collected and maintained separately so that all test

animals would be in the same age class. Juveniles used in this test were separated from adult tanks on 4 April 1985 and held for 18 days before the test

began. All mvsids were fed maintenance levels of brine shrimp (25-30 nauplii/ -".

mysid) twice per day.

Test Sediment

Sediment was collected vith a stainless steel Van Veen grab from a site

on the west end of North Island, San Diego Bay (Figure 2). The North Island

site was selected for sediment collection because grain-size composition and

contaminant levels have been well documented. The sediment has been demonstrated to be reasonably "uncontaminated" during previous bioassays. A

physical/chemical description of the sediment used in this test is given in

Table 1. It is classified as very fine sand (Wentworth 1922).

Sediment from the grab was stored in 60-Z ice chests lined with plastic

bags. Ice chests were used for ease in handling sediment and to maintain the

temperature of sediment between collection and storage. The sediment was

stored for 72 hr at 40 C. Approximately 50 1 of sediment was collected. The

sediment was sieved through a 1.0-mm stainless steel screen to remove endemic

organisms and achieve homogeneity. After sieving, I £ of sediment was distributed to each of the 10 sediment tanks (five controls and five treatments).

This I k of sediment produced a 20-mm layer on the bottom of each "substrate"

test tank. Seawater was allowed to flow through all 20 test tanks (10 with

sediment and 10 without sediment) for 21 days before starting the test. Seawater to half of these tanks contained the TBT leachates.

179
V_%-.V _W _L4wlf _I- W -W-W-WN-WJ J J ,

4.

NKf

ISAN

-4TR

Figure .. Site map

* Seawater

Nearshore seawater available at the NOSC Marine Life Scilences 1hrtr

was used I-r this toxicity test. The seawater intake lor this system was approximately 250 m from Thore (Figure 2). This natural seawater was passed

through large sand filters prior to laboratory use.

In the laboratory physical and chemical parameters of- incoming seawater

were measured during the test with the Seawater Quality Monitoring System

(SQMS) developed by NOSC. This system consists of several commercially available sensors arranged in an in-line manifold system. Output is recorded with

a data acquisition system linked to a microcomputer. Parameters monitored

daily included pH, temperature, and salinity. l)issoived oxvgen was measured

*with a hand-held meter. Seawater temperature was measured at 14.1 to 15.30 C,

*salinity at 32 to 33 ppt, dissolved oxygen at 6.5 to 7.9 ppm, and pH at 7.8 to

8.0. Thie light regime consisted of a 14L:JOT) cycle as recommended in the

.41%
:* 1CAl., CHF.MICAl. D)ESCRIPTION OF "CONTROL SEDIMENT"

T% I'IiF 'YS IWDORGAINOTIN LEACHATE EXPERIMENT

Sediment Composition Information

Percent Composition

Sand Silt Clay Classification

80.1 11.7 8.2 Very fine sand

Contaminant Information, ppm

'7'7Chromium Copper Mercury

15.0 18.0 01

PHF PCB Pesticides

0. 100 0.0060.W

Organotins, ppb

Tributyltin: 8.0

Dibutyltin: 3.0

Monobutyltin: 5.0

:r'pleentation Manual (EPA/CE 1977). Irradiance was measured with a ltter and ranged between 100 and 200 Ww/cm 2 for the Acanthornyo;2 .:-

t;3nks.

lest Conditions

Mysids ware held in 4-k polycarbonate tanks. Our research'T

metals and organometallic contaminants has shown that polvcarh)onr.t

quality glass are similar in their nonabsorptive properties (

1983). Ease in drilling for flow-through fittings, dtirab flit' .

polycarbonate tanks preferable for toxicity tests. Trhe tiou'

tank was approximately 170 ml/min. This corresponds t r .'

changes per hour (assuming complete exchange).

Mysids were fed brine shrimp nauplii (2 to'

day and aerated at a rate of 3 to 7 mI/mmn. 1Tcaid it

and removed. With 20 animals per 4-1 tank, live -

count. We counted dead animals becau-e the w !i

on the dark sediment. U'sually mvsid bocdlelive o3dy individuals atrdah could be made. cutn Py- r'!:-u' 

live animals on dav 10, we wv'e i,le t"

counting method. W e could -croit -T

experiment, q8.8 percent.
D-R1BS 119 MANAGEMENT OF BOTTOM SEDIMENTS CONTAINING TOXIC SUBSTANCES: PROCEEDINGS 0 .(U) ARMY ENGINEER MATERNAYS EXPERIMENT STATION VICKSBURG MS ENVIR. T R PATIN

BBBBBBBII

UtNCLAS7SIFIED APR 9? F/G 24/3 NU.

EIIIEIIIIIIII

mhhElhhhlhhlhI

m§/hhBIIIIElhI
112- 1.02.2

1111 136 [2.

11L25
Toxicant

The TBT toxicant was introduced as a leachate from AF paint on Plexiglas

panels. Panels (15 by 15 cm) were coated with SPC-956 (International Paint,

Inc.). This paint contains 9.4 percent TBT methacrylate, 0.5 percent bis(TBT)

oxide, and 44.7 percent cuprous oxide as the toxicants. Two coats were

applied by dipping the panels into the paint can, allowing them to dry overnight, and dipping them again. These panels were installed in the polycarbonate troughs of a flow-through seawater delivery system previously

developed (Meador, U'Ren, and Salazar 1984). In this system (Figure 3) seawater is forced to flow over a series of panels at a rate of 6 k/min before

distribution to test tanks. The concentration of TBT in seawater delivered to

test tanks is determined by the flow rate of incoming seawater and the number

of panels in the mixing trough.

During an 8-week equilibration and stabilization period without sediment

in test tanks, chemical measurements were made to determine the TBT concentration in the leachate. By altering flow rates and removing panels, the approx- imate desired concentration of 0.60 ppb TBT was achieved. Previous measurements of leachates from this coating system have demonstrated that the copper

concentration is about twice the TBT concentration. However, due to differences in effective toxicity, the effects of copper are relatively insignificant. This concentration was selected after review of the most current toxicity data. In a previous flow-through experiment without sediment, 0.61 ppb

TBT produced 50 percent mortality in 4 days with 1- to 3-day-old Acanthomysis

a 0

DRI

I a.X

CONTROLMXNTAKLCAT MIXING TANK "

'"¢.Figure 3. Flow-through bioassay system

0002

. ". -,~

' ",,'#" # "#" .. '2 .'+ .- ." .. " '..".''+.,. .. " " e'+ .. .,' -+- + ,.+',,+",,p".,..v,,.."..,,.' +"+,. ','.,- .".,", % % + _ %. .. " .'.. .. " \ .,",.
scuipta juveniles (Valkirs, Davidson, and Seligman 1985). TBT concentrations

were measured by hydride derivatization atomic absorption spectrophotometry

(HD-AAS) (Valkirs et al. 1985b).

Organotin Measurements

The concentration of TBT in seawater and sediment was monitored before A

and during the assessment. Four sets of tanks were prepared as chemical

blanks. By comparing TBT measurements in tanks with and without mysids, we

could assess the effect of mysids on TBT chemistry. Each set consisted of two

tanks, one tank with sediment and one without (total of eight tanks). No

mysids were added to these chemical blanks. Three sets were used to monitor

organotin concentrations in the seawater during the test. The fourth set was

used as a chemical blank for the controls to monitor potential TBT contamination. Seawater from the TBT chemical blank tanks was measured prior to starting the test to confirm the concentration of TBT in the leachate solution. A

50-ml aliquot of seawater from each of the three chemical blank tanks was

pooled for one composite sample. In addition to samples from the chemical

blanks, seawater to be used for chemical analysis was collected from the out- .

flow ports of treatment tanks to avoid stressing the test animals.

Composite seawater samples of 100 ml each were collected from the following sets of TBT treatment tanks on a daily basis: mysids with sediment,

mysids without sediment, chemical blanks with sediment, and chemical blanks

without sediment. Polycarbonate bottles were used for the samples. After

collection, samples were frozen until chemical analysis. The HD-AAS was used

to determine the TBT concentration in both sediment and seawater samples. All .,

samples were not analyzed due to constraints in analytical support.

RESULTS

The sediment/organotin toxicity test with mysids was conducted between

March-May 1985. Praily mysid survival (from daily counts of dead animals) is

presented in Table 2 by replicate, with total percent survival by test condition. Percent survival versus time for each of the four test conditions is

presented in Figure 4. Inspection of the data shows there was no significant

difference in survival among any of the treatments during the first 6 days of O-W

the test. The two-way ANOVA confirmed no statistically significant effect in

either substrate or toxicant treatments. Sediment did not become a statistically significant factor until day 7 (Table 3). The effect was positive in

that mysid survival was greater with sediment than without sediment. Mysid

survival in TBT-SO tanks began a significant decline 2 days before a significant decline in TBT-SS tanks. By day 8 there were two statistically significant effects on mysid survival, sediment and TBT. The sediment (substrate)

effect remained positive, but the TBT (toxicant) effect was deleterious. Con- 1%

trol survival in the CSO and CSS tanks remained constant at 95 and 100 percent, respectively, from day 7 to day 10, the end of the experiment. Survival

data from days 8, 9, and 10 showed significant effects due to sediment and

TBT. The sediment (substrate) effect was positive while the TBT (toxicant)

effect was deleterious. No interaction effect was shown.

In the TBT-SO tanks mysid survival dropped rapidly from 95 percent on

day 6 to 90 percent on day 7, 83 percent on day 8, 64 percent on day 9, and

30 percent on day 10. Survival of mysids in TBT-SS tanks remained high at

183

"V..6.
TABLE 2. SURVIVAL OF MYSIDS EXPOSED TO ORGANOTIN-CONTAMINATED

SEAWATER WITH AND WITHOUT SEDIMENT

Time, days

Tank Rep 0 1 2 3 4 5 6 7 8 9 10

CSO 1 20 20 20 20 20 20 20 20 20 20 20

2 20 20 20 20 20 20 20 20 20 20 20

3 20 20 20 19 19 19 19 19 19 19 19

4 20 20 18 18 18 17 17 17 17 17 17

5 20 20 19 19 19 19 19 19 19 19 19

100% 100% 97% 96% 96% 95% 95% 95% 95% 95% 95%

CSS 1 20 20 20 20 20 20 20 20 20 20 20

2 20 20 20 20 20 20 20 20 20 20 20

3 20 20 20 20 20 20 20 20 20 20 20 %

4 20 20 20 20 20 20 20 20 20 20 20

5 20 20 20 20 20 20 20 20 20 20 20

100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100%

TBT-SO 1 20 20 20 20 20 20 20 19 18 11 6

2 20 20 20 20 20 20 19 19 19 17 10

3 20 20 20 20 20 20 20 18 16 10 2

4 20 20 19 19 19 19 19 18 15 12 3

5 20 20 19 18 18 18 17 16 15 14 9

100% 100% 98% 97% 97% 97% 97% 907 83% 64% 30%

TBT-SS 1 20 20 20 19 19 19 19 19 19 17 11

2 20 20 20 20 20 20 20 20 20 16 8

3 20 20 20 20 20 20 20 20 19 17 7

4 20 20 19 19 19 19 19 19 19 16 11

5 20 20 20 20 20 20 20 20 19 17 9

100% 100% 99% 98% 98% 98% 98% 98% 96% 83% 46%

96 percent until day 8 and then dropped rapidly to 83 percent on day 9 and

46 percent on day 10. The difference in mysid survival between toxicant tanks

was statistically significant on days 7, 8, and 9. Survival of mysids exposed

to TBT with sediment was greater than survival of mysids exposed to TBT without sediment. The difference on day 10 was not statistically significant. In

addition to no significant interaction effect on survival between sediment and

organotin, there was no statistically significant difference in survival between controls (CSO and CSS) when compared with a Mann-Whitney U Test

(Tables 3 and 4).

The concentration of TBT toxicant in the mixing trough 3 days before the

test began was measured at 0.60 ppb TBT. During the test TBT concentrations

184 - .

RN~~~~ % .

01
tO0 -

* CIO

20 - TBT1SS

S10 * TITSO

40 20 I I I0

0 2 4 a 10

TIME (DAYS)

Figure 4. Mysid survival ,

TABLE 3. RESULTS OF TWO-WAY ANOVA PERFORMED

ON THE MYSID SURVIVAL DATA

Probability Level

Day "F" Value Prob > F Toxicant Substrate Interaction

7 4.5858 0.01683* 0.10410 0.00557* 0.47088

8 8.5866 0.00126* 0.00558* 0.00240* 0.12916

9 21.5859 0.00001* 0.00000* 0.00308* 0.05918

10 57.0658 0.00000* 0.00000* 0.03779* 0.25287

* A < 0.05 indicates a significant effect.

in the TBT-SO tanks with mysids varied from 0.41 ppb to 0.80 ppb TBT with a

mean of 0.60 ppb TBT. TBT concentrations in the TBT-SS tanks varied from

0.54 ppb to 0.78 ppb with a mean of 0.60 ppb TBT. The means were the same for

both TBT treatment conditions. The TBT-SO chemical blanks varied from

0.37 ppb to I.11 ppb TBT and had a mean of 0.78 ppb TBT. The TBT-SS chemical

blanks varied from 0.47 to 0.80 ppb TBT and had a mean of 0.61 (Table 5).

The clean sediment used in this test had TBT levels below the limits of

detection. Further, sediment did not accumulate detectable quantities of

organotins during 31 days of exposure to seawater containing an average TBT

concentration of 0.A0 ppb. There were no measurable increases in tri-, di-,

or monobutyltin in cp:it sediments since organotin were below the limit of

detection before and after exposure to TBT leachates (Table %).

..-N,-

)i" V
TABLE 4. RESULTS OF MANN-WHITNEY U TEST*

Day U-Critical U-Calculated

TBT-SO Versus TBT-SS Data

7 21.0 23.0*

8 21.0 23.0*

9 21.0 36.5* ..

10 21.0 19.5 .-P

CSO Versus CSS Data

10 21.0 20.0

* If U-Calculated > U-Critical, there is a statistically significant differ- V

ence at the 95 percent confidence level when a = 0.05

TABLE 5. ORGANOTIN CHEMISTRY SUMMARY TABLE

(CONCENTRATIONS IN PPB TBT)*

Composite Seawater Chemistry SamlesT -3 T

Samples o o Day 2 Day 3 Day 7 Day 9 Day 10 Mean

Chemical blanks

TBT-SS 0.47 0.57 0.80 0.61

TBT-SO 0.6 0.37 0.87 1.11 0.78

Mysid tanks e %

TBT-SS 0.58 0.55 0.57 0.54 0.78 0.60

TBT-SO 0.41 0.46 0.53 0.79 0.80 0.60

Sediment Chemistry**

TBT-SS Samples T Day 10

Tributyltin <8.0 <8.0

Dibutyltin <3.0 <3.0 ,

Monobutyltin <5.0 <5.0

* At T the control sediment had been exposed to a nominal concentration of

approximately 0.6 ppb TBT for approximately 21 days. By day 10 the sediment

had been exposed to TBT for over 31 days. .

** All butyltin concentrations were below detection limits.

DISCUSSION

Based on the results of the two-way ANOVA there was no significant effect

attributed to a 0.60-ppb TBT exposure after 6 days. By day 7 there was a significant effect attributed to sediment and the effect was positive. The

186

-P~~~~~~1 * *. . .. VL..
reason for this statistically significant effect is higher survival in both

sediment treatments (CSS = 100 percent, TBT-SS = 98 percent) than in the seawater treatments (CSO = 95 percent, TBT-SO = 90 percent). This may appear to

be anomalous, but we have routinely seen higher survival of mysids in dredged

material bioassays in the presence of sediment than in the absence of sedi- ,

ment. This positive effect attributed to sediment continued from day 7 to

day 10, the end of the experiment.

By day 8 there was also a significant effect attributed to the TBT toxicant. This effect was deleterious. Mysid survival dropped from 90% on day 7

to 83 percent on day 8. This deleterious effect attributed to the TBT toxicant continued from day 8 to day 10. Mysid survival dropped precipitously in b

b'-'n TBT-SO and TBT-SS treatments near the end of the experiment. These data

s ,6 est that juvenile mysids are capable of withstanding low-level exposures

to TBT for periods up to 6 days. The actual toxic insult was present during

the entire 6 days, but the result of that insult was not expressed as death

until day 7. This trend has been noted in previous work performed with TBT

and mussels (Mytilus edulis) (Smith 1979). One possible explanation is a

cumulative effect over time or a deterioration of the animal's defense mechanisms. A 6-day experiment with the same design and TBT concentrations followed by a recovery period without TBT would clarify the 6-day effects of

0.60 ppb TBT in Acanthomysis sculpta. Pickwell and Steinert (1984) have

described a quantifiable sublethal stress measurement for mussels exposed to

copper. A similar system would prove useful with mysids or other sensitive

test animals. Until those techniques are available, death is the most

reasonable measurement.

Daily inspection of the control and treatment tanks revealed that mysids

exposed to TBT leachates were generally less active than control animals.

Treatment mysids did not respond as quickly to stimuli such as changes in

light intensity or the presence of moving objects in test tanks, i.e.,

pipettes to remove dead animals. In many instances the mysids from treatment

tanks were not actively swimming but rather "resting" or debilitating on the

bottom. Similar responses with copepods have been described by U'Ren (1983).

Throughout the test the control animals were very active and demonstrated

behavior patterns similar to freshly collected mysids held under standard

laboratory conditions.

During the experiment mysid survival was higher in the presence of

sediment. However, at the end of the experiment when mysids remained on the

bottom for extended periods, the presence of sediment may have become a deleterious factor. We believe the animals were smothered by sediment if they

remained on the bottom in a weakened condition. The ANOVA could not extract

this effect on day 10 due to the magnitude of the positive effect in both the

CSS tanks (100% survival) and the TBT-SS tanks. The Mann-Whitney U Test

showed that mysid survival in TBT-SS tanks was significantly greater than in

TBT-SO tanks on days 7, 8, and 9. There was no statistically significant !-

difference in mysid survival between those tanks on day 10. There was no %..

statistically significant difference in mysid survival between CSO and CSS

tanks at any time. Chemically, the positive effects of sediment in the TBT-SS

tanks were still present, but they were probably tempered by the physical

effects -)f smothering. This was not the case in the TBT-SO tanks where mysids

could remain on the bottom without bei'ig covered with sediment.

187 . . . .. .. .. . . . . ..
VV [V W'_'_

' %.

The question of environmental significance in every toxicity test is an

important one. Since we have shown that mysids exposed to organotins exhibit

higher survival in the presence of sediment than the absence of sediment, it

can be assumed that in other toxicity tests with mysids, similar results would

occur if each experiment had a paired design such as this one. The next question is which experimental design best represents conditions in the marine

environment. We suggest that toxicity tests with sediment are more realistic

than toxicity tests without. Sediment may reduce toxicity and bioavailability

through physical and chemical processes related to sediment particles and naturally occurring organics. There may also be some chemical in the sediment

that increases mysid survival. Our experiment may underestimate toxicity .. 4.

since the volume of sediment was a significant portion of the total volume in

the tank. However, standard toxicity tests in sterile glass aquaria with few

organics, particles, or sediment probably overestimate toxicity. This raises

doubts about much of the TBT toxicity data that exist in the literature. The

expected toxicity of organotin-contaminated sediment from a previous experiment (Salazar and Salazar 1984) was not realized because it was probably affected by some of these physical/chemical processes.

Waldock and Thain (1983) have shown that sediment affected oyster

(Crasoostrea gigas) growth rates. Compared with the control without sediment,

oyster growth rates were higher in the tanks with sediment. When exposed to

TBT concentrations between 0.15 ppb and 1.6 ppb, growth rates were higher in

tanks with sediment and TBT than in tanks with TBT only. The only mortalities

occurred in tanks with TBT.

Another problem in assessing potential environmental impact is interpreting the relationship between toxicity data reported from the laboratory and

field measurements from contaminated areas. The problem with the TBT toxicity

literature has just been discussed. The problem with field measurements is

that they are usually discrete samples taken at one point in time and space

and may be quite variable. Zirino, Lieberman, and Clavell (1978) have shown

that the concentration of certain heavy metals can vary by a factor of three

or more with tidal cycle. They have explained that within San Diego Bay the

incoming tide transports a large volume of clean, uncontaminated ocean water

into the bay. The outgoing tide carries a large volume of water that has been

contaminated from sources within the bay. Recent measurements by our labora- e

tory at one particular location within San Diego Bay have shown that variations in TBT concentration approach an order of magnitude during the tidal

cycle. These measurements raise even more questions regarding field measurements previously reported for San Diego Bay (Valkirs et al. 1985a) and their

significance as related to toxicity values previously reported. Further, the

variability in TBT concentration in our test system precludes a precise LC-50

determination, which enhances the problem. Attempting to extrapolate environmentally significant numbers for regulatory purposes by using these data is k

not reasonable.

The bioavailability of contaminants and their actual toxicity in seawater

are highly variable. Although a minimum concentration of certain trace metals

is important for phytoplankton growth (Guillard and Ryther 1962), the form or

chemical state of those metals determines whether or not they are usable by

organisms (Johnston 1964). Studies on some species of phvtoplankton show that

growth inhibition and copper uptake are related to cupric ion activity and not

to total copper concentration (Sunda and Cuillard 1976). Along with others,

188 -. "

%9 ~ .q..
%1

6.

we have shown that toxicity is also related to the state of the cupric ion .,

tested (Smith 1979). In experiments with mysids and brine shrimp nauplii,

TBT was far more toxic than its degradation products, dibutyltin and monobutyltin (Seligman 1984). The addition of sediment to test tanks reduces the

toxicity of copper to Neanthes arenaceodentata (Pesch and Morgan 1978) while

the type of sediment influences copper toxicity and copper bioaccumula- N

tion (Pesch 1979).

It has been shown that organic chelators are often the most crucial

factor in bioavailability of nutrients for phytoplankton growth in seawater

(Johnston 1964, Barber and Ryther 1969). It has also been suggested that, except for copper and iron, complexing agents have a relatively minor effect on

initial complexation in seawater and that organic compounds adsorbed on the

surface of sediment particles control the adsorption of metals (Morel and

Morel-Laurens 1981). Although the actual chemical mechanism is unclear, some

organics found in natural sediments can reduce toxicity and bioavailability.

The results of our previous experiment (Salazar and Salazar 1984) suggest that

something in the TBT-contaminated sediment had the capacity to reduce toxicity

and bioavailability of TBT in that sediment.

The present study suggests that something in the sediment may have reduced the toxicity and bioavailability of the TBT leachates. Another alternative may be that the sediment itself adsorbed a significant amount of TBT.

However, TBT adsorption was not measurable. Measurements of TBT from sediment

in TBT-SS tanks was below 8.0 ppb before, during, and after the experiment,

and not significantly different from the CSS tanks.

In addition to naturally occurring organic chelators in sediments that

reduce toxicity and bioavailability, animals also have the ability to sequester and detoxify contaminants. There are several possible methods of detoxification. Accumulated organotins may be modified by the animals to become

biologically unavailable, or they may combine with lipids to reduce toxicity.

- Organotins may bind to metallothioneins (Roesijadi 1981) or be sequestered

within cellular organelles (George et al. 1978). In each case, there is a

reduced opportunity for toxic expression.

Thus, when estimating the potential toxicity of organotin AF leachates

from Navy hulls to marine organisms, more effort should be directed toward

duplicating natural conditions. This will prevent overestimating toxicity

values and reduce the significance of questionable values currently appearing

in the literature. For our purposes, however, the survival of mysids exposed 4.

to TBT leachates was higher in the presence of sediment than the absence of

sediment. Questions could be raised about the variability of TBT concentra4. tions during the 10 days of exposure. The flow-through leachate system

"- described here is not perfect, but the alternative is less desirable. TBT

solutions are very unstable, time-consuming to prepare, and present a storage

problem for experiments of any length. To clearly define an LC-50 for

Acanthomysis sculpta, a flow-through leachate system as used here is not the

most appropriate technique. As in LC-50 tests we conducted with

Metamysidopsio elongata (Smith 1979) and those conducted with A. tonsa (U'Ren

4 1983), a more appropriate technique would be a static renewal test using

leachates. In the present study using 18-day-old juveniles, the 10-day LC-50

for Acanthomysis scuipta exposed to TBT leachates in the presence of sediment

was approximately 0.60 ppb TBT. Only one concentration was used in this

48. 189
46

experiment, and thus it is impossible to predict precisely the comparable

10-day LC-50 for mysids exposed to TBT leachates. A 30 percent survival at a

nominal 0.60 ppb TBT was observed after 10 days. The concentration necessary

to produce 50 percent survival under these conditions is higher than for

mysids exposed to leachates and sediment simultaneously.

An additional problem is that new contaminants like organotins are not

well characterized. As they are studied further, new insight should be gained

into their toxicit means of improving the required ecological evaluation of

dredged material and standard toxicity tests. The Navy research programs to

expedite dredging and study the fate and effects of organotins in the marine

environment will help guide the assessment of the potential for environmental

impact. However, as the use of organotins increases, so will the need for

additional work to understand fully the chemistry and bioavailability of

organotins and to predict their effect on the marine environment.

CONCLUSIONS

The results of this toxicity test demonstrate that sediment affects the

survival of mysids exposed to organotins. Juvenile Acanthomysis scuZpt

exhibited higher survival in the presence of sediment than in the absence of

sediment. The variability in TBT concentrations during the course of the

experiment precludes an accurate LC-50 prediction and raises doubts about

LC-50 values reported by others using similar systems. Further, the absence

of sediment in some of these other experiments probably indicates an overestimation of organotin toxicity. The environmental significance of all

available data with regard to fleetwide implementation of organotin AF coatIngs is not clear. Additional work is required to understand fully the

chemistry and bioavailability of organotins and to predict their effect on the

marine environment. The Navy and regulatory agencies like CE/EPA should work

closely together to establish realistic criteria for fleetwide implementation

and dredging. The approach in testing organotin toxicity should be reevaluated in terms of environmental significance using protocols that address TBT

variability in test tanks, the significance of field measurements, and the

effects of sediment on survival.

ACKNOWLEDGMENTS

This study was sponsored by the Environmental Protection Office of the

Naval Facilities Engineering Command through a program to expedite Navy dredging. Analytical support was provided by the Energy Office of the Naval Material Command through a program to determine the fate and effects of organotins

in the marine environment.

We wish to thank all of our chemistry/biochemistry colleagues for helping

us understand the importance of accurate chemical measurements during toxicitv

tests and all of our friends at the Marine Life Sciences laboratory who reviewed this manuscript.

Special thanks are due Steve Hurley who has supported our programs in

environmental quality for the last I0 years when many within the Navy did not

understand the relevance of our research. Special thanks are also due Marc

Weissman who provided technical assistance, ideas on experimental design and

interpretation of results, and moral support.

1 90

9

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i:i

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REFERENCES %,

Barber, R. T., and Ryther, J. H. 1969. "Organic Chelators: Factors Affect- %

Ecol., ing Primary Vol 3, Production pp 191-199.in the Cromwell Current Upwelling," J. Exp. Mar. Biol. a

Dooley, C. A., and Homer, V. 1983. "Organotin Compounds in the Marine Environment: Uptake and Sorption Behavior," Naval Ocean Systems Center Technical ~Report No. TR 917.

Environmental Protection Agency/Corps of Engineers. 1977. "Ecological Evaluation of a Proposed Discharge of Dredged Material into Ocean Waters,"

Environmental Effects Laboratory, US Army Engineer Waterways Experiment

Station, Vicksburg, Miss.

George, S. G., Pirie, B. M. S., Cheyne, A. R., Coombs, T. L., and Grant, P. T.

1978. "Detoxication of Metals by Marine Bivalves: An Ultrastructural Study

of the Compartmentation of Copper and Zinc in the Oyster Ostrea edulis," Mar.

Biol., Vol 45, pp 147-156.

Guillard, R., and Ryther, J. 1962. "Studies on Marine Planktonic Diatoms,"

Can. J. Microbiol., Vol 8, pp 239-299.

'N

Johnston, R. 1964. "Seawater, the Natural Medium of Phytoplankton, II, Trace

Metals and Chelation, and General Discussion," J. Mar. Biol. Assn. U. K., J

Vol 44, pp 87-109.

Mauchline, J. 1980. "The Biology of Mysids and Euphausiids," Advances in

N-, Marine Biology, J. H. S. Blaxter, Sir F. S. Russell, and Sir M. Yonge, eds.,

Vol 18, Academic Press, London, pp 1-681.

Meador, J. P., U'Ren, S. C., and Salazar, M. H. 1984. "A Flow-Through Bioassay System for the Evaluation of Organotin Antifouling Compounds," Water

Research, Vol 18, No. 5, pp 647-650.

Morel, F. M. M., and Morel-Laurens, N. M. L. 1981. "Trace Metals and Plankton in the Oceans," Trace Metals in Sea Water, C. S. Wond, E. Boyle,

K. W. Bruland, J. D. Burton, and E. D. Goldberg, eds., Plenum Press, New York.

Pesch, C. E. 1979. "Influence of Three Sediment Types on Copper Toxicity to

the Polychaete Neanthes arenaceodentata," Marine Biology, Vol 52, pp 237-245.

Pesch, C. E., and Morgan, D. 1978. "Influence of Sediment in Copper Toxicitv

Tests with the Polychaete Neanthes arenaceodentata," Water Research, Vol 12,

AN pp 747-751.

Pickwell, G. V., and Steinert, S. A. 1984. "Serum Biochemical and Cellular

Responses to Experimental Cupric Ion Challenge in Mussels," Marine Environ.

Research, Vol 14, pp 245-265.

Roesijadi, C. 1981. "The Significance of Low Molecular Weight

Methallothionein-Like Proteins in Marine Invertebrates: Current Status,"

Mar. Environ. Res., Vol 4, pp 167-179.

191 12

%, % %

" " "" " " ","• . .. . .. _ _ " '7 f .$L," L .'% L " " _ '.
Salazar, M. H., and Salazar, S. M. 1984. "Ecological Evaluation oi

Organotin-Contaminated Sediment," Proceedings 10th U.S./Japan Experts Meeting

on Management of Sediments Containing Toxic Substances, October 30-31, 1984,

Kyoto, Japan.

Salazar, M. H., and Salazar, S. M. 1985. "Acute Effects of (Bis)tributyltyin °e

Oxide on Marine Organisms," Naval Ocean Systems Center Unpublished Technical

Report.

Seligman, P. F. 1984. "Fate and Effects of Organotin Antifouling Leachates

in the Marine Environment," Progress Report I Oct 82 - 30 Sept 83 prepared

for Energy Research and Development Office, David W. Taylor Ship Research and

Development Center, and Chief of Naval Material.

Smith, P. J. 1979. "Toxicological Data on Organotin Compounds," International Tin Research Institute Publication No. 538.

Sunda, W., and Guillard, R. L. 1976. "The Relationship Between Cupric Ion

Activity and the Toxicity of Copper to Phytoplankton," J. Mar. Res., Vol 34,

No. 4, pp 511-529.

U'Ren, S. C. 1983. "Acute Toxicity of Bis(tributyltin) Oxide to a Marine

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Valkirs, A. 0., Seligman, P. F., Vafa, G., Stang, P. M., Homer, V., and P

Lieberman, S. H. 1985b. "Speciation of Butyltins and Methyltins in Seawater

and Marine Sediments by Hydride Derivatization and Atomic Absorption

Detection," Naval Ocean Systems Center Technical Report No. TR 1037.

Waldock, M. J., and Thain, J. E. 1983. "Shell Thickening in Crassostrca

Cgaj: Organotin Antifouling or Sediment Induced?," Mar. Poll. Bull., Vol 14,

No. 11, pp 411-415.

Wentworth, C. K. 1922. "A Scale of Grade and Class Terms for Plastic

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Zirino, A., Lieberman, S. H., and Clavell, C. 1978. "Measurement of Cu and

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A.. I 192 2, -- ~ ~ ~ ~ ~ ~ -.- . ~ ."'... ~ ~ .° . . .. . . .. . . .. . . .
FOOD CHAIN STUDIES AT TIMES BEACH CONFINED

DREDGED MATERIAL DISPOSAL SITE -\

BUFFALO, NEW YORK %

iI

Richard P. Leonard

US Army Corps of Engineers ,e

Buffalo District, 1776 Niagara Street

Buffalo, New York 14207 %

ABSTRACT

The 46-acre Times Beach Confined Disposal Facility (CDF) Buffalo, New York, was half filled with polluted dredged material between 1972 and 1976. Filling

was stopped at the request of environmental groups because of the large numbers of migratory waterfowl and

birds which occupied the area. In the intervening

years, open water, wetland, and wooded upland zones

have evolved with associated wildlife and vegetation.

An objective of the biological and chemical studies in

progress at Times Beach is to determine the extent to

which contaminants in the dredged material are bioaccumulating in plants and animal food chains in the

three environments of the Times Beach CDF. A further

long-term objective is to determine if bioaccumulation

()r biomagnification produces deleterious effects on

food chains including chronic toxicity, suppressed reproduction, carcinogenicity, and disruption of community structure.

Up the the present time, wetland and aquatic

plant communities, earthworms, fish, insects, and

toads have been sampled from the disposal area and

analyzed for heavy metals, polychlorinated biphenyls

(PCBs), and polyaromatic hydrocarbons (PAHs). Results

of these samplings and analyses are reported in this

paper. The data showed less accumulation of metals in

plant seeds than in leaves or rhizomes. Cattail rhizomes were high accumulators of heavy metals, especially cadmium and arsenic. Aquatic plants accumulated greater concentrations of metals than wetland

plants. Very low concentrations of organic contaminants were found In plant samples.

Accumulation of metals in earthworms at Times

Beach was much higher than accumulation in earthworm.q

from a natural reference area. Cadmium levels in

earthworms were elevated. In general, metal levels in ,., r insectc. and toads J rom dredged material and a

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contiguous background location were comparable. Cadmium appeared to be higher in insects from the dredged

material.

Concentrations of heavy metals in fish indicated

that mercury was more elevated in fish from the Times

Beach site compared with a reference site at the mouth

of the Buffalo River. PCBs and PAHs were also more

elevated in fish from the Times Beach CDF.

Mammal, fish, and bird polulations have been inventoried at the Times Beach CDF. Future study will

be directed at sampling and analyzing key higher food

chain species at the Times Beach for contaminant bioaccumulation and effects.

INTRODUCTION

- ,

The Times Beach disposal area is a 46-acre confined dredged material disposal area near the confluence of Lake Erie and the Buffalo River. The site

received approximatelv 550,000 cu yd of polluted dredged material from the

Buffalo River and Buffalo Harbor from 1972 to 1976. While being filled, the 2.

area became intensively used by migratory waterfowl, songbirds, and other

wildlife. "ver 200 species of birds and ducks have been observed at the Times

Beach site (Andrle 1985). At the request of local environmental groups, filling was stopped in 1976 because of the large numbers and varieties of birds

using the site. The completely enclosed area now contains about 50 percent

shallow open water (I to 7 ft deep), 25 percent marsh, and 25 percent scrub

trees. Figure 1 is an aerial photograph of the site.

The marsh wetland is vegetated primarily with cattails, smaller areas of

phragmites, rice cutgrass, purple loosestrife, and minor inclusions of sedges

and rushes. The more elevated upland portion of the disposal area contains

primarily cottonwood trees generally in the 2- to 10-in.-diam range. Understory consists primarily of dogwood, goldenrod, willow, and impatiens.

A 1985 animal survey (Andrle 1985) showed muskrat to be common in the

marsh area, while cottontail rabbits frequented the wooded area. This survey

inventoried 26 species of resident and breeding species of birds at the site.

Although the area is observed to foster lush vegetative growth and abundant wildlife, there is concern that contaminants from the sediment may accumulate and bioconcentrate in plant and animal food chains. Consequently, a

long-term program has been initiated to study bioaccumulation by aquatic and

terrestrial plants and animals, and possible effects on organisms including

growth, reproduction, vitality, and carcinogenicity. This paper describes

initial work on chemical characterization of sediment and bioaccumulation by I

plants, earthworms, fish, insects, and toads. %

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Al thoughl much work has been done (in biO,-ccuImI.It ion by the above organ-"."

ism.s in controlled experiment- in the laboratory and at the Times Beach site ,'

(.'1arquenie, Simmers, and Kav 19}85), thi, paper will he concerned with bio-O

na-cumulat ion by natural plant and animal COMMUnitie, . ":

ST1'1)Y ME'II(IU .);"- .

'ege tit ion Assoc iat ions I''

Veg;eta-ion special ists examined the Times Beach disposal site and ideate! ied aind mapped five major vegetation associattions as q-,flwn in Figure 2.

, -ri i s open water varying from I to 7 ft in depth with ;I meain de'pth o ,

t > '.() ftt. 'fI.'l; area exhibits prolific algal growth ind an ahlnld !nCe of atitACjl( ,And flanting ;iq(uatic plantc4 1Cin ling potclMogetOT1 (pondwe,.d) and "

Ar(v;i .) c h/ir/-iu ter i ze(d ;ilmos't (at iretv bv br(o,-d anidt n~l r -w ]e (I I ',Ittt.1i "

t'. pj), I , wh il I ar(.., 1 11,1!; T-1ixed c"Itt ta il I .;i d phra)'r i t k.; . Areal . h1,'t; minlv "

k," ' , .)d M thIe ;IrL',t WOD w dI Ifd i:; d )m ill,-]ted bV\ ((t tOnWOO~d (p, pII)U IuI I . A re,' I

i '; do>mi I];'t t ] h pllril .r t e k !i c e (it r ss itll( purple, Ioo ;(,;t rile atre' ilI;o

hl )i 111 I'l 11t i l IT Ir(.:i '.i

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I - Open Water

2 - Cattail (Typha)

3 - Mixed Phragmites and Cattail

4- Sedges

5 - Woodland (Poplar)

6 - Phragmites Ja

Figure 2. Location of Times Beach vegetation

zones and sampling transects

Transects (A and B in Figure 2) were laid out for sampling of vegetation,

soils, and earthworms from vegetation areas 2 through 5. In addition, sediments, plants, and fish were sampled from the open water of area No. 1. Insects and toads were sampled from pitfall traps located in the wooded area as

shown in Figure 3 (area 5 of Figure 2). Part of area 5 is nondredged soils -

and was sampled for background levels of contaminants in insects.

The approximate location of the pipe which discharged hydraulically

dredged sediments from the Buffalo River and Harbor into the Times Beach is

shown in Figure 2. This method of discharge resulted in deposition of coarser

material (sand and gravel) and higher elevated topography in the vicinity of

the discharge pipe. Silt and clay were carried further out into the disposal

area at lower elevations.

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A 10 " " o *MX Bckground . -. -

rronsect C . .

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Site I .€

(25m) ite 7 (45m) ,.

Site 8 (80m)"-=

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Figure 3. Position of (65r.) pitfall traps placed in the upland area ,

of the Times Beach confined disposal site ;

'-O

River at the point where it flows into Lake Erie, just north of the disposal ,.

A. %

site. Reference samples of earthworms were obtained from Grand Island are located 

in the Niagara River about 12 miles north of Buffalo. The soils of this area

were undisturbed but probably had received atmospheric fallout of pollutants

from the Niagara Falls/Buffalo industrial complex. -..

RESULTS AND DISCUSSION

Soils :

As discussed previously, sandier sediments were deposited on the surface

nearer to the pipeline and finer silts and clays carried out further. ispos

19.i

sit.e. Reference samples.. "-".".",- of"earthworms we,re obtaind f. G. I.and l

in aout12 te Nagar mlesnort Rier ofBufflo. The oil of hisare
Figure 4 illustrates sediment profiles advancing from the pipeline in the

woodland through the wetland and into the open water. In the intervening

9 years since disposal ceased, there has been considerable drying and oxidation in the sands of the wooded area, whereas the silts of the wetland and

open water bottom remain saturated and chemically reduced. These physical and

chemical differences are believed to be of considerable significance to the

chemical transformation and bioavailability of inorganic and organic pollutants present in the sediment. Sampling transects were arranged to examine the

physical, chemical, and biological differences proceeding from the discharge

pipe point of entry to the open water of the disposal area.

The brown sandy surface sediment, especially in the woodland, has a

"natural" soil appearance and odor with no visual or olfactory suggestion of

contaminants. This layer dries out in summer months and is oxidized with the

appearance of reddish iron-oxide colors. The underlying black to grey silty

sediment has a semiliquid consistency and a strong oily odor. This chemically

reduced material appears to be practically unchanged from the time of deposition, and the depth to this material appears to coincide with the permanent

water table.

In June 1981, 16 surface samples of sediment were analyzed from the wetland and woodland. Metal and organic pollutants found are given in Table 1.

Additional sediment analyses are given with plant uptake data. Major organic

pollutants include PAHs and aniline compounds. The major source of PAHs is

believed to be coking facilities from steel plants in the Buffalo Harbor and

Buffalo River. Aniline compounds originate from a dye plant on the Buffalo

River.

Vegetation

Four different plant species from the wetland area were identified as

important food sources for local birds and ducks. Samples of these species

were collected along with soil around their roots. Species collected included

two rushes (Carex stipata and Scirpus atrovirens), cattail (Typha latifozia),

and Phragmites austrailis. In addition, whole plant samples of pondweed

(Pot ao eton) and elodea were collected from the open water. Seeds, leaves,

and, in the case of cattail, rhizomes were analyzed individually. Results of

the plant analyses are given in Table 2.

The data show that, for all species analyzed, accumulation of metals in

seeds is less than in leaves or rhizome. Seeds and leaves of the wetland

plants (cattail, phragmites, rush) do not appear to accumulate toxic heavy

metals to any extent. Aquatic plants (elodea, potamogeton) accumulated heavy

metals to a much greater extent than the wetland plants.

Cattail rhizomes are seen to be high accumulators of heavy metals and may

biomagnify cadmium and arsenic. Since rhizomes constitute an important food %

for muskrats, which are common at the site, future work will be directed at

obtaining and analyzing muskrats for transfer of metals through the food

chain. Roots of the wetland plants have also been collected for analysis %

since the rhizome data indicate that roots of other plants may have higher

metal levels than leaves or seeds.

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TABLE 1. METAL AND ORGANIC ANALYSES OF TIMES BEACH

SURFACE SEDIMENTS (w~g/g DRY WEIGHT)*

Pollutant Range Mean

Metal

Zinc 1031-1845 1283

Cadmium 10.9-13.3 11.9

Copper 238-269 251

Arsenic 2.6-58.9 22.7

Mercury 2.9-9.4 4.8

Nickel 49-63 55

pChromium 302-393 332

Lead 156-1037 497

Organic

Bis(2-ethylhexyl) phthalate 1.5-5.5 3.0

PCB(Aroclor 1242) 0.42-1.0 0.75

PCB(Aroclor 1254) 0.62-2.5 1.5 .*

Aniline 1.7-2.8 2.3

1-amino-napthalene 1.7-4.1 2.7

N-benzyl-N-e thyl-anil The 2.4-7.0 4.5

4-(dimethyl-amino) benzo phenone <0.1 <0.1

4,4-methylene bis (N, N-dimethyl-aniline) 0.54-1.4 0.93

N,N,N',N'-tetramethyl benzidine <0.1 <0.1

p,p'-benzylidene bis (N, N-dimethyl-aniline) 2.6-4.7 3.3

benzo- (a) -pyrene 20-96 3.9

Chlordane <0.2 <0.2

Toxaphene <0.2 <0.2

Dimet-hyl phthalate <0.2 <0.2

Diethyl phthalate <0.2 <0.2

Dibutyl phthalate <0.2 <0.2

Benzyl butyl phthalate <0.2 <0.2

Lindane <0.1 <0.1

Heptaclor <0.1 <0.1

Aldrin <0.1 <0.1

p,p'-DDE <0.1 <0.1

Dieldrin <0.1 <0.1 d

Endrin <0.1 <0.1 ~ .

p,p'-DDD <0.1 <0.1

psp'-DDT <0.1 <0.1 -

Methoxyclor <0.1 <0.1

Mirex <0.1 <0.1

Phenol <1.7 <1.7

0%

*16 samples.

200
TABLE 2. METALS CONCENTRATION, VEGETATIVE

ANALYSES FOR TIMES BEACH -Vi

Metal, wg/g dry weight

As Cd Cr Cu Hg .-

Sample .- I S-2 S-1 S-2 S-1 S-2 S-1 S-2 S-1 S-2

C. stipata (Rush) j

Seed 0.17 0.18 0.22 0.12 0.57 0.16 7.5 8.8 0.029 0.031

Leaf 0.22 0.27 0.97 0.24 0.92 0.81 11 6 0.028 0.036

Sediment 74 48 4 4 177 129 228 232 4.71 3.83

T. ZatifoZia (Cattail)

Seed 0.07 0.05 ND 0.48 0.03 ND . 16 13 0.003 0.009 #. ,"1%

Leaf 0.15 0.14 2.76 1.44 0.26 0.21 4.9 3.7 0.021 0.023 .."

Rhizome 59 39 6.85 5.88 29 70 49 96 0.294 1.19

Sediment 117 39 8.89 2.27 268 106 350 149 9.16 2.41

P. australis (Phragmites)

Leaf 0.15 0.39 0.06 0.11 0.4 2.3 15 15 0.024 0.052

Sediment 81 62 3.3 4.8 206 287 249 215 4.27 5.88

S. atrovirens (Rush)

Seed 0.05 0.11 0.03 0.07 0.12 0.13 11 10 0.02 0.02

Leaf 0.17 0.17 0.41 0.13 0.5 0.9 8.5 8.9 0.05 0.04

Sediment 28 26 1.03 0.76 73 100 94 77 1.21 2.18

Aquatic Plants

As Cd Cr Cu Hg .

Pota- 12 1.7 11 11 0.19

mogeton

Elodea 6 2.3 6.3 26 0.13

.

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EARTHWORMS -I..

Native worms were collected from the wooded area of the Times Beach site

and from the reference area on Grand Island. Very few earthworms were found

in the wetland portion of Times Beach, probably because of the high water -

table and periodic inundation. The only worm species collected at the Times %

Beach site was Tumbricus rube lus, a species which confines itself to the top %

layer, rich in humus. Two composite samples consisting of 85 and 57 worms

each were collected and analyzed. Two composite samples each of three worm .1

species (Lumbrious rubeZ7.us, Octalasium 7acteum, and AlZobophora chZorotica)

were collected and analyzed from the reference site. Concentrations of heavy

metals, PCBs, hexachlorobenzene (HCB), and PAHs for the worm samples from both

sites are given in Tables 3-5. PCB and PAH components are identified in

Table 6.

The data show significantly greater accumulation of heavy metals by

. rubelius at the Times Beach site compared with the reference site. Biomagnification of cadmium and perhaps arsenic is indicated. It should be noted

that metal concentrations in worms from the reference site are also elevated

when compared with values cited in the literature•.

Table 4 shows much greater accumulation of PCBs by worms from the Times

Beach woodland despite somewhat low sediment levels. Similarly, PAHs were 2-

much higher in worms from Times Beach. PAHs are elevated in Times Beach

sediments.

Insects and Toads

Insects and toads were collected from pitfall traps at the 12 locations

shown previously in Figure 3. All samples were collected from the wooded portion of the site. Earthworms which fell into the traps were also analyzed.

The purpose of this sampling was to identify dominant groups of soil-dwelling

invertebrates; to determine levels of the heavy metals Zn, Cu, Cd, Ni, Pb, and

TABLE 3. METAL CONCENTRATIONS (i.g/g ASH-FREE DRY WEIGHT) IN

NATIVE WORMS AT TIMES BEACH AND A REFERENCE AREA

Area Species Cd Cu Hg As

Times Beach I. tube Ious 113.0 59.7 1.33 30.8

84.4 58.3 1.95 52.9

Reference . rubellus 17.6 20.2 0.469 8.84

22.4 30.2 0.549 11.8

-

A. hlor otica 24.3 11.4 1.76 10.8

22.5 10.4 2.00 10.4

. ctcum 36.5 12.5 1.77 6.47

50.7 14.8 2.34 9.59 WV%

202

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TABLE 6. NOMENCLATURE OF PCB AND PAH COMPONENTS

UNDER STUDY WITH REPORTING CODE NUMBERS

PCB Components

28 2,4,4', - trichlorobiphenyl

52 2,5,2',5', - tetrachlorobiphenyl

49 2,4,2',5', - tetrachiorobiphenyl

70 2,5,3',4', - tetrachlorobiphenyl

101 2,4,5,2',5', - pentachlorobiphenyl

87 2,3,4,2',5', - pentachlorobiphenyl

153 2,4,5,2',4',5', - hexachlorobiphenyl

138 2,3,4,2',4',5', - hexachlorobiphenyl

180 2,3,4,5,2',4',5', - heptachlorobiphenyl

PAH Components

1 phenanthrene

2 anthracene

3 fluoranthene

4 pyrene

5 3,6-dimethylphenanthrene

6 triphenylene

7 benzo(b)fluorene

8 benzo(a)anthracene

9 chrysene

10 benzo(e)pyrene

11 benzo(j)fluoranthene

12 perylene

13 benzo(b)fluoranthene

14 benzo(k)fluoranthene

15 benzo(a)pyrene

16 dibenzo(a,j)anthracene

17 dibenzo(a,i)pyrene

18 benzo(g,h,i)perylene

19 indeno(1,2,3-c,d)pyrene

20 3-methylcholanthrene

21 anthanthrene

Cr in each taxa; and to assess the potential value of these organisms for use

as indicators of heavy metal mobility in the ecosystem. A complete inventory

of the numbers of individuals trapped in each order and family is contained in

Strafford (1985). Although sufficient carnivcrous and detrivorous insects for -

analysis were collected in this study, herbivorous invertebrate numbers were *.

insufficient for analysis. Future studies will include larger numbers of

herbivores.

Tables 7 and 8 contain data on metal levels in soil invertebrates, and

Table 9 contains data on metal levels in toads. Table 10 compares levels of

metals in insects from Times Beach to contaminated and uncontaminated sites

from the literature. In general, metals levels in insects and toads from

205

%* * 5 . . .
.5-o

TABLE 7. MEAN METAL CONCENTRATIONS IN SOIL INVERTEBRATES, TIMES

BEACH WOODLAND DREDGED MATERIAL (wg/kg DRY WEIGHT)

Invertebrate Zn Cu Ni Cd Cr Pb

Carnivore

Beetles 104 15 <1 2 4 <5

(Coleoptera)

Spiders 376 193 <17 85 40 <30

(Araneida)

Centipedes 246 54 <8 11 13 <12

(Chilopoda)

Detrivore

Millipedes 208 632 2 3 7 8

(Diplopoda)

Wood Lice 177 141 3 39 13 14

(Isopoda)

Earthworm 833 94 12 60 41 62

(Oligochaeta)

the wooded dredged material area and the wooded background soil are con.parable. However, cadmium appears to be higher in insects from the dredged material. Table 10 indicates that metal levels in invertebrates from the Times

Beach dredged material are higher than uncontaminated sites from the literature, and comparable with contaminated sites.

From the results available, it appears that spiders reflect the greatest

accumulation of the elements Zn, Cu, and Cd at the carnivore trophic level.

Uptake of Zn, Cu, and Cd is evident from metals and analyses of wood lice.

However, both Zn and Cu appear to have been accumulated to a greater extent by

millipedes. Strafford (1985) examined the stomach contents of Bufo americanas

and suggested that these toads had been feeding on many of the same species as

were collected in the pitfall traps. Comparison of metal levels in the invertebrates collected at Times Beach (Tables 7 and 8) with metal levels measured in the toads (Table 9) indicates little or no bioaccumulation of trace

elements between trophic levels. This may imply little mobility o'- the heavy

metals from invertebrate prey into vertebrate predators, but may alsu bo an

indication that B. arcricanas would be a poor indicator species for -e i,,

studies of metal mobility.

Discussion of the mobility of heavy metals between trophic levels in the

upland zone of the Times Beach ecosystem is incomplete due to the lack of data

on heavy metal concentrations in herbivorous Invertebrates. Specimens repre- S

sentative of the herbivore trophic level could be acquired using a longer .

sampling period. From the results available at present and summarized in

206
TABLE 8. MEAN METAL CONCENTRATIONS IN SOIL INVERTEBRATES,

TIMES BEACH WOODLAND BACKGROUND (wg/g DRY WEIGHT)

Invertebrates Zn Cu Ni Cd Cr Pb

Carnivore %

Beetles 139 16 0.65 0.95 2.3 <2

(Coleoptera)

Spiders 339 97 <6 14.6 23 <17

(Arane ida)X'

Centipedes 314 93 2.08 4.16 11.3 <6

(Chilopoda)

Detrivore

Millipedes 189 642 1.75 1.89 7.4 12

(Diplopoda)

Wood Lice 200 173 2.76 18 14.5 10

(Isopoda)

Earthworm 942 144 10.9 39 22 27

(Oligochaeta) . .

TABLE 9. MEAN METAL CONCENTRATIONS IN TOADS,

TIMES BEACH (wg/g DRY WEIGHT)

Sample Zn Cu Ni Cd Cr Pb

Whole specimen

Dredged material 132 53 2 5 5 6

Background 132 56 1.1 6 6 7

Liver

Dredged material 130 136 <4 8 13 <15

Background 107 272 <) 5 18 <11

K idne y ,zi

Dredged material 194 48 <11 12 39 <40

Background 183 89 <10 7 49 <3.

hone

6redged material 179 7 <1 3 15 <5

Background 1149 13 <2.3 1.9 14 .8

p.-

-' (37

I .o
TABLE 10. COMPARISON OF METAL LEVELS FOR INVERTEBRATE TROPHIC LEVELS

AT TIMES BEACH WITH LITERATURE VALUES (ig/g DRY WEIGHT)

Site Zn Pb Cd Cu

Uncontaminated sites (literature)* NZ,-

P.'. Carnivores 60 55 2 -6 23 Detrivores .... 2 19

Contaminated sites (literature)* 0.

Carnivores 270 130 11 - 33 568

Detrivores .... 13 343

Times Beach (dredged material)

Carnivores 242 <5- <30 33 87

Detrivores 193 11 21 387

* Strafford (1985).

Table 7, there is some indication of accumulation of Cd and Zn, but not Cu or

Pb between the detrivore and carnivore level of the ecosystem. Further

studies involving some replication which would enable statistical analysis to

be carried out are necessary to confirm any trends suggested by the results

given in Table 7.

Fish

Fish species were collected from the open water of the Times Beach confined disposal site and from a reference area in the Buffalo River. Each -.

species was pooled into one sample. In order to make a risk assessment for

local human consumption, fish fillets (muscle) were prepared. Liver tissues

were prepared in order to evaluate the presence of contaminants on a physiological basis and to compare Times Beach with the reference site for contaminants that do not accumulate in muscle tissue (e.g., cadmium).

Concentrations of heavy metals in fishes from Times Beach and a reference

site (mouth of the Buffalo River) are given in Table 11. These results indicate that only Hg in fish is more elevated at Times Beach and approaches but

does not exceed human food safety levels (Marquenie, Simmers, and Kay (1985).

PCB and HCB concentrations in fishes are shown in Table 12. Higher con- %1r,",

centrations were found in fishes collected at Times Beach than in fishes of

the aquatic reference site. The highest levels were found in muscle tissues

of the carp. The total concentration of the nine isomers that were analyzed

exceeded 1 pg/g (fresh weight basis). The concentrations in the livers were

much higher for all species. The highest total concentration exceeded 8 wg/g

for yellow perch.

Table 13 provides the concentrations of PAH components in fishes from

Times Beach and the aquatic reference area. Clearly, only the most soluble

and most volatile PAH components are found in the tissues. Known mutagens

208
~. .-a

'%,

TABLE 11. METAL CONCENTRATIONS (pg/g ASH-FREE DRY WEIGHT) IN FISHES AT

TIMiES BEACH AND THE ADJACENT MOUTH OF THE BUFFALO RIVER

Area Species Organ Cd Cu Hg As

Times Beach Yellow perch Muscle <0.013 2.44 1.16 0.214 f-.

Liver 0.042 1.32 0.102 0.936

Pumpkinseed Muscle <0.019 3.30 0.717 0.579

Liver 0.316 8.00 0.355 1.89

Rock bass Muscle <0.04 1.07 2.80 0.541

Liver 1.29 12.8 1.25 1.83 I.

Carp Muscle <0.025 2.73 0.767 0.801

Liver 0.125 8.37 0.252 0.751

Buffalo River Yellow perch Muscle <0.020 1.92 0.428 0.161

Liver 0.280 3.96 0.053 0.575

Pumpkinseed Muscle <0.028 1.99 0.730 0.534

Liver 1.26 10.9 0.363 1.82

were absent or only occasionally detected in very low concentrations. The

concentrations of the components that could be quantified were about five to -w

ten times as high in fishes from Times Beach as in those from the reference

site.

Mammal, fish, and bird populations have been inventoried at the Times

Beach confined disposal facility. Future study will be directed at sampling

and analyzing key higher food chain species at Times Beach for contaminant

bioaccumulation and effects.

REFERENCES

Andrle, Robert F. 1985(Aug). "Vertebrate Research at Times Beach Confined

Disposal Site, Buffalo, New York," Interim Draft Report prepared for Buffalo

District, US Army Corps of Engineers.

Marquenie, Johannes M., Simmers, John W., and Kay, Stratford H. 1985(Feb).

"Bioaccumulation of Heavy Metals and Organic Contaminants at the Times Beach

Confined Disposal Site, Buffalo, N. Y.," Miscellaneous Paper EL-85- (DRAFT)

US Army Engineer Waterways Experiment Station, Vicksburg, Miss.

* Strafford, E. A. 1985. "A Preliminary Investigation Into the Composition and

Heavy Metal Content of Soil Dwelling Fauna Collected in Pitfalls Traps at the

*' Times Beach Confined Disposal Site, Buffalo, New York," Rothamstead Experimental Station, United Kingdom.

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[t 212
THE INDIAN~A HARBOR EXPERIENCE

JnA. Miller

US AryCorps of Engineers

Chicago District *A

219 South Dearborn Street

Chicago, Illinois 60604-1797

ABSTRACT

Indiana Harbor and Canal is part of a highly industrialized watershed in northwestern Indiana. The

bottom sediments within the navigation channel are

highly polluted, with two reaches of the canal having

polychlorinated biphenyls (PCBs) contamination in

toxic levels (>50 ppm). The Corps has been unable to

maintain the channel for over 10 years because of the '

lack of a suitable disposal site. The Chicago Dis- -.

trict is addressing the disposal of maintenance dredgings from Indiana Harbor and Canal along two lines.

For the bulk of polluted dredgings, the District is

preparing plans for a confined disposal facility to be

constructed in Lake Michigan at East Chicago, Indiana.

For those sediments contaminated with elevated levels

of PCBs, the Chicago District has contracted with the

Waterways Experiment Station (WES) to conduct studies

on the disposal alternatives for these materials. In

addition, WES is assisting the District in evaluating

innovative dredging and disposal technologies and conducting a study on the impacts of the no-action

alternative.

INTRODUCTION

The Indiana Harbor and Canal is located in East Chicago, Indiana, on the

southern shore of Lake Michigan (Figure 1). Indiana Harbor is thle fourth

busiest port on the Great Lakes, having a deep draft navigation channel maintamned by the Corps of Engineers (CE). The Grand Calumet River, tributary to

Lake Michigan via the Indiana Harbor and Canal, has a relatively small watershed which is entirely urban/industrial. The major industries along the canal

are steel, petrochemical, lead, and gypsum. The Grand Calumet River/Indiana

Harbor Canal (GCR/IHC) has a long history of water quality problems and has

been identified by the International Joint Commission of the Great Lakes (IJC)

as a major area of concern.

J The Chicago District, CE, maintained the navigation channel at Indiana

Harbor and Canal by periodic dredging until 1972. Prior to 1970, dredglngs

were disposed to the open waters of Lake Michigan. After 1970, Federal environmnental regulations prohibited the unconfined disposal of polluted

213a

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21,

t. .,- ., % .,.,- .% ,,. -,.-. .-.. . .. ,.' , .' ,r,, l' . .. . . . '.,," .. ,i_ - .* .- . .. .- . . ,. ., . . . .", .. .

-.- ' .',r'. '. *' ,'-.*"o' ' " . .' % % % ,% ' .% %,' % 'b % I " % % . '." ''- %-II .- .
dredgings. In 1971-1972 maintenance dredgings were disposed to an enclosed

lakefill on Inland Steel. Since 1972 the Corps has been unable to maintain

the navigation channel because no acceptable disposal site was available.

Despite several attempts, the Corps could not locate a site or local sponsor

for almost 10 years. In 1983 the Corps completed a Site Selection Study for

potential dredged material disposal sites. The Lake County Board of Supervisors offered to act as sponsor for the construction of a confined disposal

facility (CDF) in Lake Michigan at East Chicago. The Corps has proceeded with

the preparation of a Draft Environmental Impact Statement to be released in

November 1985.

The dredging and disposal of polluted sediments from Indiana Harbor and

Canal have received an unusually high amount of notoriety, including consider- .

able media attention. A number of local citizens and environmental groups

have expressed their opposition to the proposed project, fearing the dredging

and disposal might endanger the quality of Lake Michigan. In November 1983, a

few months after the release of the Site Selection Study, a meeting between

the Corps, US Environmental Protection Agency (USEPA), State of Indiana officials, and representatives of citizens groups was held at the IJC biennial

conference in Indianapolis, Indiana. The citizens groups described the

GCR/IHC as a valuable resource forgotten by the State and USEPA and expressed -

doubt that the Corps would use the most up-to-date technologies in its dredging and disposal plans. At this meeting both the USEPA and Corps of Engineers, North Central Division, pledged to take actions to address the concerns

raised. The USEPA identified its intent to prepare a Master Plan for the ..

GCR/IHC, coordinating the regulatory and remedial actions necessary to improve

water quality. The Corps stated it would explore innovative technologies for

dredging and disposal of contaminated sediments.

USEPA MASTER PLAN

In 1984-85 the USEPA, Region V, prepared a "Master Plan for Improving

Water Quality in the Grand Calumet River/Indiana Harbor Canal." The Master

Plan report included a discussion of existing environmental problems and pollutant sources, a presentation of existing water quality control programs, and

recommendations for improving water quality and aquatic habitat conditions.

The summary of existing environmental problems in the GCR/IHC stated that

there were "high concentrations of conventional, nonconventional and toxic

pollutants in the sediments and overlying water column. Although improved

point source controls have resulted in significant improvements in ambient

water quality conditions in recent years, the contaminated sediments continue

to represent a major in situ reservoir of accumulated pollutants." The Master

Plan report indicated that "the continued discharge of toxic and nonconven- 5

tional pollutants (including contaminants leaching from sediments) are now the

major limitation to the biological recovery of the GCR/IHC system."

The I'SEI'A Master Plan formulated the following recommendations: %

a. (ontinue the existing cmphasis on pollutant controls. .'

215

. -. 5,.

%' ., p*- ." ,, .' '. .''." -' ' ' . ' " , ..- .. -" .. - . - " . .-. ,. -. .-. - -. . ". -. . - - . . ". ' - , . ' .' . '%
* b. Clarify the role of toxic pollutants in the river system.

c. Develop any additional toxic pollutant control programs that are

necessary for restoration of the GCR/IHC.

The recommendations are to be implemented through a cooperative, interagency effort which is directed by USEPA. The Corps' participation is centered around the Environmental Impact Statement on Indiana Harbor maintenance

dredging and its research and development study. The Corps' "assessment of

alternatives to dredging and spoils disposal from the Harbor and Ship Canal

will contribute to public and agency perceptions of the feasibility of remedial actions proposed for upriver sediment contaminations."

INDIANA HARBOR STUDIES

In 1984 the Chicago District contracted with the WES in Vicksburg, 5

Mississippi, to conduct an R&D study. The purposes of the study were

threefold. The first purpose was to fulfill the pledge made at the November

1983 IJC meeting to investigate innovative dredging and disposal technologies.

This part of the R&D study was conducted last month in the form of an equipment demonstration at Calumet Harbor, Illinois. The second purpose of the R&D

study by WES (which represents the major effort) was an evaluation of disposal

alternatives for PCB-contaminated sediments from Indiana Harbor Canal.

Thirdly, the Chicago District asked WES to investigate what has become known

as the "no-action" alternative.

Equipment Demonstration

The purpose of this study was to demonstrate two pieces of innovative

dredging/disposal equipment: a "Matchbox" hydraulic suction head and a submerged diffuser. The "Matchbox" is a Dutch-designed dredge head which had

been used effectively in Rotterdam Harbor for the dredging of highly contaminated sediments with minimal resuspension. The submerged diffuser is a Corpsdesigned "flange" to be placed at the discharge end of a hydraulic dredge

pipeline for controlled placement of dredgings directly on the ocean/lake

floor. The diffuser reduces exit velocities, reduces resuspension, and can be

used to place and cap contaminated sediments.

The equipment demonstration took place in October 1985 at Calumet Harbor

in Chicago, Illinois (Figure 1). The Corps' hydraulic dredge "Dubuque" from

the St. Paul District was used to demonstrate the equipment. The performance

of the "Matchbox" was compared with a standard cutterhead. The submerged

diffuser was demonstrated within the Chicago Area Confined Disposal Facility

(CI)F) at C;alumet Hlarbor. The results of the demonstration and water quality "#

monitoring should he available in .January 1986. ..

Disposal Alternatives for

PiCB-Contaminated Sediments

The bottom sediments of the Indiana Harbor and Canal are heavily polluted.%

with metals and organic contaminants such as PCBs and polynuclear aromatic hydrocarbons (PAHs). The levels of contamination present preclude any disposal g

of dredgfngs to the open water. Most of the sediments contain levels of con- 77-

tamination suitable for confined disposal in an upland or in-lake CDF. Two "

')10

2 l 6 %'A -'.'"

* ~. .-. a.~ *~ . .. ,... :72
reaches of the canal contain levels of PCBs exceeding 50 ppm. These sediments V- are subject to Federal regulation under the Toxic Substances Control Act

(TSCA), and the disposal alternatives are less clear. WES was asked by the

Chicago District to evaluate the feasibility of three specific disposal alternatives for these PCB-contaminated sediments and to analyze the control measures required under each alternative. These disposal alternatives are:

(1) upland CDF, (2) in-lake CDF, and (3) confined aquatic disposal (CAD).

In October 1984, 20 barrels of sediment from Indiana Harbor Canal and

Lake Michigan were collected and transported to WES. A battery of chemical,

engineering, and biological tests were performed with these sediment samples,

including:

a. Physical/engineering properties.

b. Settling and consolidation tests.

c. Solidification/stabilization tests.

d. Bulk chemical analysis.

e. Modified elutriate tests.

f. Column capping tests--chemical/biological.

g. Plant uptake.

h. Animal uptake.

i. Leachate tests.

i. Runoff tests.

The sediment collected from Indiana Harbor was a highly plastic clay,

having a high concentration of oil and grease and 12.5 percent total organic - .-

carbon content. Metals were present in elevated levels, as expected given the

industrialized area. PAHs were present in high concentrations, including

napthalene and benzo(a)pyrene. The mixed sediment sample also contained

33.4 ppm of PCB (Arclor 1248).

The tests performed by WES were used to evaluate the conditions expected

during the three disposal alternatives. Modified elutriate tests were used to

assess the quality of effluent from a CDF. Column capping tests were used to

determine the thickness of cap required to isolate the contaminated sediments

from the overlying water column. For these tests, aquatic organisms (fish, ,

clams, and crayfish) were placed in the column over capped and uncapped sediments. Plant (sedge) and animal (worm) uptake tests were used to determine

the potential for bioaccumulation in an upland CDF.

In addition to the above testing procedures, WES scientists have been

developing new methods to simulate the processes of leaching and runoff in

confined dredged material disposal. This effort was necessary because there

2 17

d.

'-.- ';';-.'''- .:- --;.'" """. -"";-;- "''.,. """, , ."t ,.-" :"" . ,",' % ..'" . .. ' ,"":'L- """. , '''- " .. ..
was either no standardized method available or the existing method was too %

costly or time-consuming. Mr. Tommy Myers of WES will be giving a presentation at this meeting on the development of leachate testing protocol. ,N

The preliminary results of the WES analysis of disposal alternatives for %0..

PCB-contaminated sediments from Indiana Harbor Canal are being reviewed by the

Chicago District and North Central Division at this time. It appears that,

with certain design and operational control measures, all three disposal alternatives would be feasible from an engineering and environmental basis. The

specific control measures are beyond the scope of this paper. The final report should be available in January 1986. Following review of this report by

the USEPA and State of Indiana, the Chicago District intends to discuss the

selection of a disposal alternative with these agencies.

No-Action Alternative

The performance of maintenance dredging has long been viewed as a necessary evil by the public and environmental groups--a messy operation having no

redeeming value except to navigation users. This preconception has been challenged only recently. If the USEPA can use dredging as a remedial action for

a cleanup under Superfund, how is maintenance dredging that different?

When the Corps prepares an Environmental Impact Statement for a planned

maintenance dredging and disposal, no action is one of the alternatives evaluated. Typically this alternative is examined only for economic impacts.

Yet, if the proposed action is to remove polluted sediments from a river or

harbor and place them in a confined environment, are there not some positive

environmental impacts as well? Navigation channels are often located at the

mouth of a river and act as a settling basin trapping sediments which would

otherwise be transported out to the receiving water body. The maintenance of

this sediment trap should be especially important if the sediments are heavily

polluted and the quality of the receiving water is highly valued.

The Chicago District asked WES to evaluate the no-action alternative at

Indiana Harbor. Since it was recognized th t this was a large undertaking,

WES agreed to do a "first-cut" investigation during 1985. This study was to

examine the existing information on the GCR/IHC system, literature on the

interaction between bottom sediment-water column, and sediment transport

information. "..-.. %

The study would attempt to prioritize the mechanisms by which the

polluted bottom sediments impact the water quality of the river and adjacent

lake and to identify laboratory or field investigations necessary to quantify

these impacts. Preliminary findings indicate that sediment-bound contaminants

represent the most important mechanism for water quality impacts and that .

field studies of the suspended sediment sources and transport are of highest

priority. The conclusions and recommendations of the no-action alternative

study will be available in January 1986.

SUMMARY

The experiences of the Chicago District at Indiana Harbor have shown the

current perceptions of the public and regulatory agencies toward the environment, dredging, and the removal of in-place toxic pollutants. The public is -. ,

218

,.. .W

;,;,:,, ,~~~~~~~~..............-..- ..... ..-.....-.......-.... ;... . ... .... .-- .. - , .. : ,....... ...-.. , .-.-.,. -. -. , . .- , - ,..
-%rVVP67W,%-L ArA1IV,,% -,

becoming 

and 

recognized 

maintaining 

increasingly 

that 

environmental 

environmental 

impatient 

quality. 

problems 

with regulatory 

are 

Organizations 

not solved 

agencies 

such 

by 

tasked 

study 

as the 

alone. 

with 

IJC 

restoring 

have

At

U

their recent biennial conference in Kingston, Ontario, the Water Quality Board

of the IJC expressed this in the theme of their presentation "Let's Get On

With It."

At Indiana Harbor, the Corps and USEPA have opportunity to make significant improvements to the existing environmental conditions. The USEPA has

formulated a Master Plan to coordinate regulatory and remedial measures. The

Corps has proposed a plan for dredging most of the navigation channel and has

completed studies on innovative dredging technologies, disposal alternatives

for PCB-contaminated sediments, and the impacts of the no-action alternative.

With this information in hand, the Corps should be able to remove and confine

a portion of the in-place pollutants from Indiana Harbor under its navigation ,.

authority. The USEPA will be able to define the environmental benefits from

the removal of in-place pollutants beyond the navigation channel and evaluate

the feasibility for a remedial cleanup action using dredging/disposal alternatives developed by the Corps.

219.

7-A

*- j

' 219 7

mm i l i i .4 ' i d. . . ... . . . . 4.............. .. r . n" . . - . - - .4 - - l
% .-.

THE MOVEMENT OF SEDIMENT UNDER

A PROGRESSIVE WAVE .4

Michio Gomyoh, Eiji Yauchi, Hiroshi Kojima

Japan Dredging and Reclamation Engineering Association

ABSTRACT

Bottom sediments in the shallow sea and in-bay

have very high water and organic matter content.

These sediments are easily resuspended and settled,

and flow easily under tidal currents or waves. These

phenomena have caused many environmental problems,

such as water pollution and decreased fairway depth in

harbors and bays. In order to solve these problems,

an hydraulic experiment on the movement of sediment

under a progressive wave was carried out under differing conditions of water content.

It was found that the length of the sediment

ripple on the interface between the water layer and

sediment layer, the wave height of sediment oscillation, and the attenuation rate of progressive wave

height reached maximum values when the water content

was about around 247 to 250 percent.

Further, these characteristics could be evaluated

by a nondimensional number 0(= .'o/2 v sediment • d)

which was obtained from the thickness of both laminar

boundary layer and sediment.

INTRODUCTION

A great volume of soft sediment has settled in the shallow sea and in-bay

due to transportation of organic matter and sands from rivers and deposition

of suspended substances. The following are characteristics of this kind of

sediment:

a. High composition of very fine soil particles.

b. High natural water contert.-

c. Easily resaspends and flows.

d. High content of organic matter. I e. Very small bearing capacity.

-2 2G9 - i - % -%
This kind of sediment is easily resuspended and settled, and flows easily

by tidal currents or waves. Therefore, these phenomena have caused constant

water pollution and decreasing fairway depths in harbors and bays. TI o movement of the bottom sediment is very complicated, and studies of t iese phenomena are few (Ohtubo 1983, Sumitomo, Ishibashi, and Kuriyama 1975, 'agai,

Yamamoto, and ludwig 1983). In particular, the study identifying the difierence of physical properties of sediment is not almost carried out.

To solve the problems caused by these phenomena, a method to predict the

movement of sediments under the currents or waves must be obtained.

This paper will focus att- cion on the movement of sediments with

differing properties, such as water content, under the progressive wave in

order to clarify the mechanism of movement in the shallow sea and in-bay.

EXPERIMENTAL APPARATUS AN) PROCEDURE

The wave tank used in this test was 21 m long, 1.5 m deep, 1.5 m wide,

and was equipped with a piston-type wave maker, as shown in Figure 1.

2.5m

I ight

video camera

wave maker

bentonite

wave meter

U

____25m

Figure 1. Experimental apparatus

A uniform bottom slope having a gradient of 1/20 was set up at the

down-wave side of thle tank as a wave absorber, and bentonite (as shown in

Table 1) was put in the trench, which was 2.5 m long and 7 cm deep at the

center of the tank.

Experiments were carried out under 91 conditions. Water content and wave

height were changed from 200 to 270 percent and from 0.3 to 8.3 cm, respectively. Wave period, water depth, and sediment thickness were fixed at

1.05 sec, 20 cm, and 7 cm, respectively.

22] N.

.................... tal appaatus" ....- *...........................'-...%% '
TABLE 1. CHARACTERISTICS OF BENTONITE .

'V.

Specific gravity 2.60

Median diameter 34 prn

Texture Sand 4%

Silt 42%

Clay 54%

Liquid limit 160.2%

Plastic limit 24.7%

The following were measured or observed:

a. Attenuation rate of wave height over sediment.

b. Development process of sediment ripple.

c. Resuspension of sediment.

d. Wave height of sediment oscillation.

e. Phase lag between wave motion and sediment oscillation.

Viscosity of sediment was measured by a rotary viscometer (cylinder type)

in order to determine flow characteristics. The influence of consolidation

was neglected because the test was completed within a few hours.

RESULTS

Physical Properties of Sediment

Physical properties of sediment should be separated into (a) that independent of water content such as chemical components, ingredient texture,

liquid and plastic limits; and (b) that dependent on water content such as%

density and viscosity. In this experiment, apparent density and flow characteristics were tested.

Shearing rate and shear stress are used as the physical indexes of shear- '

ing flow, and yield value is used for plastic flow. Figure 2 shows flow

curves of bentonite at each water content. In this figure, D is shearing

rate, S is shear stress, and the gradient of curve shows viscosity. Accord- %1,

ing to Figure 2, the viscosity of bentonite becomes high with decreasing of

water content, and the flow curve shows that bentonite is a non-Newtonian

fluid.

222
%-

".% 

(PC)

150 W226 %I

/0 AJ 

.- '-'21.0

-100

0

."0

~ 247

o 0010 

Shearing Rate, D

20 

270 

(sec-)

7

Figure 2. Flow curve of bentonite ' -

The viscosity n 0for the low shearing rates (0-10 sec-1) was calculated using this curve. The kinematic viscosity Vsediment that was calculated using n and the apparent density p are shown in Figure 3. This

figure shows that n and W (water content) are proportional at the range

of the water content in this experiment. However, the viscosity was too high

to measure by the viscometer in the case of bentonite with W of 200 and

211 percent. Therefore, the values of n were determined by extrapolation.

Movement of Sediment . '

The sediment behaved as described below with increasing wave height:

a. Appearance of sediment ripple on the surface of sediment. The sediment ripple appeared on the sediment surface when the progressive

wave height was fairly small.

b. Growth of sediment ripple. As the progressive wave height increased,

the length and height of the sediment ripple became large. Moreover,

the profile of the sediment ripple was asymmetric, leaning in the .'i-.'

opposite direction of the progressive wave.

c. Resuspension of sediment from the crest of sediment ripple. When the

progressive wave height became larger, resuspension of sediment from

the crest of the sediment ripple was observed.

223

; %. %

2 2 3 ,.:..' ' ",

* .1 .

2 . -

°

"- . °... " . - . . .' - . .- ., - - .- - .-.......... .- . w.. . -" " " -" -p"•" - " - . .%2
2' , '- "

.. _.-i

lsediment \ U ) .

V~sediment

1.5 0 -10

sediment

dsedim'ent (Crn 2

/sec)

',\.- .5

\0 & \

SO\ sgcmse -

( 2- 770/p%

sediment sediment

1.0 '0 "," 200 300

W(%)

Figure 3. Viscosity of bentonite

d. Oscillation of sediment. The phenomena mentioned in a and c were

observed on the sediment surface. However, when the progressive wave

height exceeded a certain height, the whole sediment began to

oscillate.

b-:i

e. Wave motions and destruction of sediment. The oscillation of sediment mentioned in d became large gradually, resulting in the wave .

motions or destruction shown in Figure 4.

The appearance time and the scale of these phenomena vary with differing

sediment physical properties. Therefore, in order to study further the movement of sediment, the influence of water content on the growth of the sediment

ripple and the oscillation of the sediment was examined. Figure 5 shows the 7%..

relation between the wave length X at the center of the trench and the water

content W . In this figure, the progressive wave height Hi was measured at

the fixed bed on the incident side. The length of the sediment ripple increased as the progressive wave height increased. Figure 5 shows that the

lengths of the sediment ripple are maximum at W = 247-250 percent for each -

wave height. O

Similarly, Figure 6 shows the relationship between the wave heights (Hmmeasured 

and 

side. 

Hm2) 

The 

of 

at 

wave 

sediment 

a position 

height 

oscillation 

of 

1 and 

sediment 

2 m 

and 

from 

oscillation 

water 

the end 

content, 

of 

increased 

the 

in 

trench 

which 

with 

on 

Hml 

increasing 

the 

and 

incident

Hm2 were 

wave

'U

height, and maximum values were reached at W 247-250 percent in all cases.

224

2 2 4 % ".A -,
.0

IlkV

Figue o desructon 4.Procss o sedmen

(M M) H0.71.

510 

3 1

7 ft20 250--.

0 4...

Figuestrctin 4 Proessof ofsedmen 4 22. I'm-
(mm) (mm) H

0 8.33cm

2m 7.07

_5.71 1 -1 - 1 3.83

10 10 • 2.81

Hml Hm2.

/ /

010

, ,I/

[, / , "/

AI , ,

I / i / ,I

0 -

200 250 (/ 200 250 (%) ..,

Figure 6. Relationship of wave height of sediment oscillation

and water content

Interaction of Wave and Sediment

The movement of sediment was discussed above. As the sediment movement .','

increased, the sediment and wave began to interfere with each other. In this

experiment, the wave attenuation, which progressed over the sediment, was

observed as reported by Nagai, Yamamoto, and Ludwig (1983).

The change of wave height as it progresses over the sediment is shown in

Figure 7, in which the abscissa is a measuring position of wave height. The

attenuation of wave height became considerable as the progressive wave height

became large. Further, it seems to be maximum at W = 247-250 percent in all

cases.

The attenuation rate Dw of wave height when the wave progresses by unit

length is shown in Figure 8, which indicates that the maximum value of Dw '

exists at W = 247-250 percent.

The phas lag 6 between the sediment movement and the progressive wave

(the wave height is 8.3 cm) is shown in Figure 9, where 6 is positive when . .

the phase of sediment movement proceeds with one of wave. According to

Figure 9, the phase lag 6 is zero at W = 247 percent. Moreover, this value

of W is the same water content value as when the length of sediment ripple, ,.

the wave height of sediment oscillation, and the attenuation rate of

progressive wave height are maximum.

226

Le. o.

. .,. . . ,, .- ..- .- . ,.., .- - . ..-,- ,,,.- .,- .-.. ... , . . , . . . . . ." -
N V , 

%'-'

X-225m wave X-02 bm

(C m) x

10 Wz200%/ 211 226 240 247 257 270

aV.

H.-

0~

o 8.33 c0 3...

0.2 .252.5 2.5 0252.2 05 225 02505 225 0.525

Figure Re 7. atnattnion aehih rgesn vrsdmn .

* a'r

0 .0

22.1 .

a. "0 1.99'

rate~~~d an waeotn I-

-<<4:/ .---

" H -- ___, , ...

. "/ ',,,

" 522 8252.5 .252.5 .2 22502 2 5 .5225 0 2. o,-.-.

" €,. jw

'I(.n 227'

., ,, °,9
p..

7r 5

4- °

Figure 9. Phase lag between ,

(50sediment oscillation

0 and progressive wave

200 250 (%.

w

DISCUSSION

According to the results presented earlier, the attenuation of the wave

progressing over the sediment and the movement of sediment are concerned with

the phase lag between wave and sediment oscillation. Therefore, the two layered model shown in Figure 10 was examined with reference to Dalrymple I Liu's

(1978) method. In this figure, the upper fluid is water which has the density

P and the kinematic viscosity v , and the lower fluid is sediment which has

P sediment and v sediment (n i /P sediment).

0

p V

at

Psediment sediment .

Figure 10. Two-layered model

When the wave progresses over the sediment, the pressure of the wave acts

vertically on the sediment, and the velocity V due to the vertical

228

-,----- S IS 
, X ..: d2 j~ 7. ': -j . b, h. :..:. _:P . : L % % - - L %% " - " - . • - - - - -

displacement occurs on the face of the sediment oscillation (V = d /dt). ,. 4

At this time, the upper fluid does the work P - V against the lower fluid. .%

When the wave and the sediment oscillation have the same phase, the work

P • V is the greatest. Further, the attenuation of wave height also increases because the energy transmission from the wave to the sediment becomes

great.

The following will be pointed out as physical properties which control

the movement of sediment:

a. Sediment thickness d

b. Kinematic viscosity of sediment v sediment

c. Angular frequency of wave a = 27/T

The nondimensional number is given by the thickness of laminar boundary layer and the thickness of sediment as follows:

=a12 • v sediment • d

The results, which are taken from Figures 5, 6, 8, and 9 by using € , .

are shown in Figures 11-14. Accordingly, these figures, values of the length

of sediment ripple, wave height of sediment oscillation, and attenuation of

wave height, are arranged by the use of 4 , and these values are maximum at

=0.6

0 2.81 cm

15 0 1.99

6 1.60 ..

A 1.19 %O

00.89

0.71

",,-:.-0.55

10 - 0 / ' N .::::

Figure 11. Relationship between

length of sediment

ripple and .A.

1z i .5S -_ .__-,,

-61

00 2 :

2

229 ~ ~ .- .- >;* ~ .z1.LZ A.. "

-*.'.%% S _' 

A--.X..
- - - I to - -0 --- - - - - -.. -. -

(mm)

0-.,

06

I12 Isedment d

o 8.33Jcm

10 0 7.07

A5.71

A 4.41

13 383 e

n 2.81

Hm2%

0 12

['/ 2 sediment *d .r %

Figure 12. Relationship between wave height

of sediment oscillation and ' a

230

%9
1ru WV WV Ww W mv W % V W.w; -W -z' WW -J' *W'- '. . . JF ',~ ~ ~

-21 (X.10

0 8.33 cm

2.8

2 • 7.r ..

'. [::l 3.8

V 012 -sediment d.!

Figure 13. Relationship between attenuation

rate of wave height and ~ 'X'%

V.

7 .4-.

* 6 -. *0.

.4.,,

4'

.4%'

0 1:

Figure 14. Relationship between phase

S.4 lag and 4

0 .i.'2

231

%I

.4.'
An experimental study where the wave period and the sediment thickness ,. were fixed was conducted to study the viscosity of sediment. More studies are

needed to clarify the sediment movement. For this purpose, a series of experiments under conditions with differing wave periods and sediment thicknesses is

planned.

REFERENCES

Ohtubo, K. 1983. "Experimental Studies on the Physical Properties of Mud and

Characteristics of Mud Transportation," No. 42, Res. Rept. from the National

Institute for Environmental Studies, Japan (in Japanese).

Sumitomo, W., Ishibashi, M., and Kuriyama, T. 1975. "Basic Studies on

Tractive Phenomena of Mud Materials by Wave Action," Proc. 22nd Conf. on

Coastal Eng. in Japan, pp 367-370 (in Japanese).

Nagai, ?., Yamamoto, T., and Ludwig, F. 1983. "Experiments on the Interaction of Waves with Soft Cohesive Sediments," Proc. 30th Conf. on Coastal

Eng. in Japan, pp 608-612 (in Japanese).

Dalrymple, R. A., and Liu, P. L. F. 1978. "Waves Over Soft Muds, A Two Layer

Fluid Model," Journal of Physical Oceanography, Vol 8, pp 1121-1131.

,-.5,"

2 3 2 S% . -i

L .." ',,'..', "; ..,., ,:, .;' ,',,' ,.";--'."..> .<.-, " -'. "'' "i.'"-',.'_, :,<--.,".. J . -, .. ..'.,'--..'.. , .y ..-..-..'-.:-.:... . .. ... , .
THE LONDON DUMPING CONVENTION AND ITS ROLE IN

REGULATING DREDGED MATERIAL: AN UPDATE

R. M. Engler

Environmental Effects of Dredging Programs

Environmental Laboratory

LIS Army Engineer Waterways Experiment Station

PO Box 631, Vicksburg, Mississippi 39180j

ABSTRACT

The Convention on the Prevention of Marine Pollu-I

tion by Dumping of Waste and Other Matter--known as

the London Dumping Convention or LDC--was formed in

* 1972 and came into force in the United States in 1975.

The policy, regulatory, and technical aspects of the

Corps of Engineers? ocean dumping program for dredged

material are directly affected by the United States

-~ being signatory to the LDC. The contracting nations

have met annually since LDC-1 met in September 1976.

Since that time, an extensive program of work was

adopted related to the implementation of the Conven-

-* tion concerning all aspects of dumping at sea.

Requirements of the LDC are discussed in relation to

the United States' domestic ocean dumping regulations.

Emphasis is placed on application of the technical

Annexes to the Convention. An update of the LDC

annual meetings includes LDC-8 and LDC-9--which met in

February 1984 and September 1985, respectively.

Future strategy at the Convention emphasized the need

for a multidisposal media approach at waste management

that places ocean disposal on an equal basis with land

based alternatives in the early planning phase of a

project.

INTRODUCTION

Navigable waterways of the United States have played a vital role in the

Nation's economic growth through the years. The Corps of Engineers (CE), in

% fulfilling its mission to maintain, improve, and extend these waterways, is

responsible for the dredging and disposal of large volumes of sediment each

year. Dredging is a process by which sediments are removed from the bottom of

v streams, rivers, lakes, and coastal waters; transported via ship, barge, or

pipeline; and discharged to land or water. Annual quantities of dredged

material average about 290 million cubic metres in maintenance dredging operations and about 78 million cubic metres in new work dredging operations with

the total annual cost exceeding $150 million (Boyd et al. 1972). Ocean disposal accounts for about 15 to 20 percent of the Corps' annual disposal

operations.

233

I:< Z.5
Sediment contamination has generated concern that dredging and disposal Z

may adversely affect water quality and aquatic organisms. Consequently? mst r

of the concern has centered on aquatic disposal. In recent years, the CE has

disposed of approximately half of the material at open-water sites. Because

many of the waterways are located in industrial and urban areas, sediments are

often contaminated with wastes from these sources.

The lead responsibility for development of ecological criteria and

guidelines regulating the transport and disposal of dredged and fill material

was legislatively assigned to the Environmental Protection Agency (EPA) to

share in consultation and conjunction, respectively, with the CE. Moreover,

the enactment of Public Laws 92-532 (the Marine Protection, Research, and

Sanctuaries Act (MPRSA) of 1972) and 92-500 (the Federal Water Pollution

Control Act Amendments of 1972) requires the CE to participate actively in

developing guidelines and criteria for regulating dredged and fill material

discharge. The focal point for the developmental research on these procedures

was the CE Dredged Material Research Program (DMRP) (Boyd et al. 1972, Brannon

1978)..,

Recent emphasis on deepwater port development for coal export and petroleum import and transfer will generate large quantities of dredged material in

specific locations. As an example, planned deepening of Norfolk and Mobile

harbors will generate about 35 and 141 million cubic metres, respectively.

Ocean disposal may be the only viable alternative for this generally clean

material. The ocean as an acceptable location for disposal of this material

must be thoroughly investigated.

LEGAL, REQUIREMENTS

rhe London Dumping Convention

The United States is signatory to an international treaty that is implemented through the Convention on the Prevention of Marine Pollution by Dumping

of Wastes and Other Matter (London Dumping Convention (LDC)). The signatory

countries to this convention shall then take all practicable steps to prevent

the pollution of the sea that is liable to create hazards to human health, to

harm living resources and marine life, to damage amenities, or to interfere

with other legitimate uses of the sea (Article I of the LDC).

The LDC was negotiated in November 1972. After ratification by 15 member

nations, the LDC came into force in the United States on 30 August 1975. The

contracting or member nations have met annually since September 1976.

The construction of the LDC is quite simple and straightforward. The

articles which comprise the legal framework of the Convention develop the

formal regulatory foundation. The Annexes (1-prohibited materials, II-materi- -

als requiring special care, and lll-provisions for developing regulatory

criteria) develop the technical framework to implement the articles, and the

interim guidelines for interpreting the Annexes or Articles comprise the

day-to-dav working level application of the LDC. The simplicity ends here.

Many legal and technical terms and constraints were ill defined, or even

undefined by the founders of the LDC, leaving the signatory countries a very

difficult job in implementatinn through their domestic procedures. The LDC.

% meets annually and conducts business on a consensus basis after debating the

234.'
%-'

issues at hand. A vote is rarely taken and is regarded as choice of last *..

resort. Issues (questions, legal and/or technical positions, rule changes, '

modifications or proposals, etc.) can only be introduced to the annual consultative meetings by member nations and thusly debated and acted upon by said

member nations. Technical and/or legal issues can also be referred to intersessional groups for further study and/or resolution. The LDC is an active

and dynamic treaty that tries to incorporate the state of the art in its

deliberations while remaining responsive to many opposing views regarding

ocean disposal.

The policy, regulatory, and technical aspects of both the Corps' and

EPA's ocean dumping programs for dredged material are directly affected by the

United States being signatory to the LDC. Domestic criteria must, at a minimum, he equivalent to and contain all of the basic constraints set forth in

the international regulations.

A Scientific Group was formed by the LDC to meet intersessionally to make

technical and scientific recommendations to the Consultative Body concerning

the ecological aspects of regulating dumping at sea. The group met in Septem- -

ber 1977 and has since met annually approximately 6 months prior to each .%""

annual LJ)C meeting.

A Task Team 2000 has been organized to identify long-term goals of the

LDC. The team's specific objective is to project the role of the Convention

in the Year 2000.

An ad hoc Legal Experts Group on Dumping also meets intersessionally on .-

an as-needed basis to discuss and/or resolve legal interpretation of the LDC.

Critical issues under discussion by this group are incineration at sea and

seabed emplacement of high level radioactive wastes.

The Deputy Director of Civil Works of the Office, Chief of Engineers,

attends the annual. meetings of the LDC as the Corps' policy representative.

Dr. Robert M. Engler of the Waterways Experiment Station (WES) is the Corps'

technical representative at both LI)C and Scientific Group meetings. Corps

participation is subsequently through membership on the US delegation (headed

by State Dept.) to the LDC.

Marine Protection

Research and Sanctuaries Act

The constraints of the LI)C affecting dredged material are promulgated

through Section 103 of the MPRSA specifying that all proposed operations

involving the transportation for dumping of dredged material into ocean waters

must be evaluated to determine the potential environmental impact of such

activities (Federal Register 1973, 1977). Implementation of this evaluation

program is aided by use of an EPA/CE Implementation Manual (EPA/CE Technical % 'IN

Committee 1977). The ocean dumping criteria also require that the published "- fx,

(Federal Register 1977) interim ocean disposal sites be designated as final

ocean disposal sites by Januarv 1980 or as amended. This designation can only

follow a comprehensive ecological investigation of the site and preparation of

a site designation (Environmental Impact Statement (EIS)) by the EPA (Federal

Register 1977, EPA 1977).

235,

-. -.-.

. .. .. . .. .. .. .. . . . . .
An ocean dumping evaluation must consider materials prohibited from

j disposal by international treaty (LDC) (EPA 1977) (Public Law 92-254); the

environmental impact; the general compatibility of the material with the

disposal site; the need for ocean dumping with a thorough review of alterna-

* tives; impacts on aesthetics, recreation, and economics; and impacts on other

uses of the oceans. Evaluations in CE regulation 33 CFR Parts 320 through 329

must also be applied.

Final regulations and criteria controlling ocean disposal of dredged

sediments were published by the EPA on 15 October 1973 (CE 1976) in the

Federal Register. The procedures (criteria) for assessing the suitability of

dredged sediments for ocean disposal consisted primarily on the Elutriate Test

(Saucier et al. 1978) in place of total sediment analysis. This procedure was

used to address short-term water quality impacts but not the longer term

benthic impacts. Bioassays were recommended only in general terms.

The MPRSA further required that the criteria for ocean disposal be uDdated at least every 3 years. The first updated criteria, which are currently in effect, were published in the 11 January 1977 Federal Register (1977).

These criteria account for provisions of the Convention on the Prevention of

Marine Pollution by Dumping of Wastes and Other Matter (Convention) and

reflect recent legal challenges by the National Wildlife Federation as to the

adequacy of the 1973 criteria (Federal Register 1973, 1977). The Convention

bans the ocean dumping of materials containing other than traces of certain

compounds. Compounds on the prohibited list are considered to be present in

trace quantities when the dumping of dredged sediments containing these contaminants will not cause significant undesirable effects (1977).

EVALUATIVE REQUIREMENTS

The potential effects of the ocean disposal of dredged material on marine

organisms and human uses of the ocean may range from unmeasurable to important. These effects may differ at each disposal site and must be evaluated on

a case-by-case basis. The Federal Register (1977) provides criteria for such

an evaluation, with an emphasis placed on direct assessment of biological

impacts, and the appropriate technical procedures are found in Parts 227 and

228 (Federal Register 1977). These procedures and their relationship to each

other are illustrated diagrammatically and completely described in the EPA/CE

Manual (EPA/CE Technical Committee 1977).

PROHIBITED MATERIALS

The first evaluation involves the presence of certain prohibited substances (prohibited pursutant to the LDC and domestic law) that may not be

ocean dumped under any circumstances. If materials such as high radioactive 4

wastes or chemical or biological warfare agents are present, the permit application must be denied without further consideration. Dredged material, however, is highly unlikely to contain these substances and must usually receive

the full technical evaluation required by the criteria.

236
EXCLUSIONS FROM TESTING

There are cases where dredged material is not considered chemically contaminated and would, therefore, cause negligible pollutional inpact when

* discharged at an appropriate disposal site. Thus, material thkt meets the

requirements of paragraph 227.13(b) of the Federal Register (1977) may be

excluded from the technical evaluations required by Section 227.13(b) and need

be evaluated only in terms of its compatibility with the disposal site and the 0

considerations of Subparts C, D, and E, and the appropriate sections of

Part 228. Dredged material that does not meet the exclusions must receive

full testing for its potential for environmental impact. The evaluative procedures emphasize biological effects, rather than simple chemical presence of

possible contaminants. Dredged material is separated for evaluation into

three phases, as defined in paragraph 227.32(b) (1) of the Federal Register

(1977). All three phases must be evaluatpd.

LIQUID PHASE

The liquid phase of dredged material may be analyzed chemically and the

results evaluated by comparison to water quality criteria for all contaminants

after allowance for initial mixing. The period of initial mixing, discussed in p

-Y the EPA/CE Manual (EPA/CE Technical Committee 1977), must be allowed before

comparing the predicted concentrations with water quality criteria. If the

* water quality criteria approach is not taken, the liquid phase must be evalu-

* ated by bioassays. The direct bioassay approach is to be used when the liquid

phase may contain major constituents not included in the water quality

criteria or when there is reason to be concerned about possible synergistic

effects of certain contaminants. In these cases liquid phase bioassay can aid

in evaluating the importance and the total net impact of dissolved chemical .

constituents released from the sediment during disposal operations.

SUSPENDED PARTICULATE PHASE

The suspended particulate phase of dredged material must be evaluated for

potential envirbnmental impact only by use of bioassays. The bioassays are

used to evaluate directly the potential for biological impacts due to both the

physical presence of suspended particles and to any biologically active contaminants associated with the particulates and/or the dissolved fraction. These

bioassays must also be conducted in light of initial mixing.

SOLID PHASE

It is generally felt that if a dredged material is going to have an

environmental impact, the greatest potential for impact lies in the solid

phase. This is because it is not mixed and dispersed as rapidly or to such an

extent as the liquid and suspended-particulate phases, and bottom-dwelling

animals live and feed in and on the deposited solid phase for extended

periods. Therefore, unless there is reason to do otherwise, the major evaluative efforts should be placed on the solid phase. Bioassays are required for

evaluation of the potential impact of the solid phase. Solid-phase bioassay

must also be interpreted in light of initial mixing and must be conducted with

appropriate sensitive marine organisms consisting of at least three species of

one filter-feeding, one deposit-feeding, and one burrowing species.

237

JA

'N_
BIOACCUMULATION

All biological evaluations of the suspended particulate and solid phase

are required by law (Federal Register 1977) to include an assessment of the

potential for contaminants from dredged material to be bioaccumulated in the

tissues of marine organisms. This is intended to assess the potential for the

long-term accumulation of toxins in the food web to levels that might be harmful to the ultimate consumer, often man, without killing the intermediate

organisms. Since concern about bioaccmulation is focused on the possibility

of gradual uptake over long exposure times, primary attention is usually given

to the solid phase that is deposited on the bottom. Bioaccumulation from the

suspended-particulate phase is considered to be of secondary concern due to

the short exposure time resulting from rapid dispersion of the suspended particulates by mixing. Because of the long-term nature of the concerns, bio- %- .

accumulation from the solid phase is best evaluated at present in the field.

This can be done only when a historical precedent exists for the proposed

operation; that is to say, past projects of similar pollutional characteristics were disposed at the site under assessment. Under these conditions a

field assessment provides the most useful information because the animals have

been exposed to the sediment under natural conditions for periods greater than

are now generally practical in the laboratory.

TRACE CONTAMINANTS

As described in the EPA/CE Manual (EPA/CE Technical Committee 1977), the

presence or absence of trace contaminants must be determined for all three

phases of the material. bection 227.6 of the Federal Register (1977) is

perhaps the key section of the criteria since dredged material may not be

ocean dumped if it contains any of the listed substances in greater than trace

amounts. This is not defined in terms of numerical chemical limits whose

environmental meaning is uncertain, but rather "...EPA came to the conclusion

that the basis for regulation (of trace contaminants) should be the probable

impact of these constituents on the biota and that the measurement technique

used should be bioassays on the waste itself" (EPA 1977). Section 227.6(b)

expresses in regulatory language the idea that trace concentrations should be

defined as those too low to cause an environmental effect (Federal Register

1977).

PERSPECTIVE

It should be made very clear at the outset that the policy of the United

States acting through the Marine Protection Research and Sanctuaries Act of .

1972 (Ocean Dumping Act) with application of the LDC constraints does not

strictly prohibit the ocean dumping of dredged material. Rather, it regulates

the dumping to prevent or strictly limit dumping which would adversely affect

human health, welfare, or amenities of the marine environment, ecological

systems, or economic potentialities (Federal Register 1973). The LDC prohibits the dumping of some materials as other than trace contaminants; however, dredged material contaminated with these prohibited materials may be

ocean disposed using capping or other special care techniques that will

rapidly render the contaminant material harmless.

% %%238
These critical domestic and international objectives are implemented

through criteria promulgated by EPA which incorporates state-of-the-art

biochemical evaluative guidance and testing procedures. The legislation

(Federal Register 1973, 1977) then requires that a determination be made such

that the dumping will not unreasonably degrade or endanger human health,

welfare, or amenities or the marine environment ecological system or economic

potentialities.

Additional evaluative guidance is set forth in EPA's regulations to

implement the Ocean Dumping Act and the international constraints. These are

known as the Ocean Dumping Criteria and present the testing and evaluative

procedures and specific constraints that must be applied to a proposed dumping

operation. With regard to dredged material, it also presents important exclusions from the mandatory and comprehensive testing requirements. It should be

noted that the LDC has also promulgated broad exclusions from the mandatory

testing and specific prohibitions for dredged material and sewage sludge proposed for ocean disposal. For those materials that cannot be excluded, a com- %

prehensive laboratory and field evaluative scheme is applied to the specific

project. The general constraints outlined in the Criteria (Federal Register

1977) are such that various tests are conducted, so that when the materials

are dumped, reasonable assurance is provided that no significant undesirable

effects will occur due either to toxicity or bioaccumulation. As previously

mentioned, there are numerous other constraints which must also be met, but

these are the most rigorous.

Obviously, none of this language, which is taken directly from the legislation, the treaty, and the regulations, strictly prohibits ocean dumping with

the exception of the trace contaminants provisions of the LDC. The legislation allows significant latitude and discretion in determining when effects

are adverse and will result in unreasonable degradation or endangerment or

result in undesirable effects.

As a consequence, ocean disposal should then be considered a viable

alternative of these regulations and evaluated on an equal basis to inland

based alternatives.

What have we learned about ocean disposal of dredged material since 1972 . or passage of the MPRSA? Studies of existing ocean disposal sites (Engler

1981; Herner and Company 1978; Lee, Engler, and Mahloch 1976; Saucier,

Calhoun, Engler, Patin, and Smith 1978), both domestically and worldwide, have e

not revealed the presence or formation of an ecological desert at any site

investigated. The physical effects, however, are obvious. The dumped materials form somewhat stable mounds. The site recolonizes rapidly with marine

organisms and many sites become favored fishing grounds; there has been no

documented effect found outside the legal boundaries of the disposal site

(Engler 1981; Herner and Company 1978; Lee, Engler, and Mahloch 1976; Saucier,

Calhoun, Engler, Patin, and Smith 1978). Sites used as often as the Mud Pump

Site in the New York Bight obviously remain in a state of physical stress as

would any routinely used part of our ecosystem, be it a superhighw.'v1 a navigation channel, or an intensively farmed agricultural area. More,,ver, there

are adequate and appropriate guidelines (Federal Register 7nd (,t .,

testing procedures (EPA/CE Technical Committee 1q77) to indfcit, tho i".

percent of the highly contaminated and toxic dredged materi., I I..

%) 39

-,I.
%

X   .N7 r

 1% %7% %F v .1 

 V N 

1 M .

-

may be unacceptable for ocean disposal and must be carefully managed and contained in a land disposal site, or it may be ocean disposed with appropriate

special care techniques.

LDC UPDATE

The LDC applies to dredged material as well as all other materials considered. for ocean disposal. However, guidance adopted by the past Consultative Mee; _ngs to the LDC has recognized that all the factors used to evaluate

the ocean disposal of some material may not be applicable to dredged material

and may in fact be excluded from the rigorous evaluation. First, the "Interim

Gudlnso the Implementation of Paragraphs 8 and 9 of Annex I (prohibited

* materials) to the LDC" provide that, with respect to dredged material, the

test procedures to be used for determining the potential for toxic effects,

persistence, inhibition of life processes, and bioaccumulation. This information is used to determine whether Annex I materials are "trace contaminants"

or "rapidly rendered harmless" (and thus exempt from the prohibitions of

Annex I). This information may not be needed if chemical characterization of

the material and knowledge of the receiving area allows an assessment of the

environmental impact. In addition, Appendix 1 to the Interim Guidelines,

"Test Procedures for the Interpretation of 'Trace Contaminants' and 'Harmlessness'"l exempts dredged material, in the absence of appreciable pollution

sources, from the chemical and biological testing requirements of the Annex I

prohibitions.

The LDC, meeting in February 1983, was asked by its Scientific Group

(which makes technical and scientific recommendations to the LDC concerning

the ecological aspects of regulating dumping at sea) to consider whether or

not d'-edged material contaminated with prohibited substances could be capped

with Liean material under the provisions of the LDC. It was generally agreed

* that capping techniques are considered to be technically and scientifically

feasible in low-energy environments and should continue as field research and

that the projects should be monitored until sufficient information is obtained

as to the acceptability of capping for a broader selection of ocean environments. (Note: Only 5 to 70 percent of dredged material considered for ocean

disposal may fall into the LDC category of being unacceptable for ocean disposal.) The Corps' research will continue to assess the technical applicability of innovative techniques such as capping and subaqueous borrow pits for

disposing of contaminated dredged material. The engineering aspects of capping contaminated dredged material and the efficiency of capping in isolating

the contaminated material from the water column and bottom-dwelling organisms

are published and are available from the Waterways Experiment Station.

The Eighth Consultative Meeting to the LDC (February 1984) adopted these

guidelines for the interpretation of Annex III to the Convention; these guideAnnex III1 need be applied to the ocean disposal of "some uncontaminated %%

dredged material." In addition and in regard to the evaluation of alterna- y

tives to ocean dumping, it was accepted by the 8th LDC that a general weighing

and balancing of alternatives be conducted by a comparative assessment of

human health risks, environmental risks, hazards, economics, and future uses

of disposal areas for both sea disposal and the alternatives. If this comparative assessment shows the land alternative to be more practical, sea disposal

should not he permitted. This is a major change in the philosophy that ocean

240

e9
disposal is a "choice of last resort." A report of the "Task Team 2000"

included the US position that the ocean disposal of dredged material meeting

appropriate standards is an acceptable alternative and may be evaluated with

all other alternatives and be considered throughout the planning and decision

process. This shift in past direction of US ocean disposal policy signals a

need for a comprehensive total waste management strategy that considers

environmental protection of land and its vital water and food resources as

well as that of the ocean. The LDC-VIII meeting also rejected a proposal to

expand the 1 ist of prohibited materials to include lead (Pb); their decision

was based on a strong US position documented by a thorough evaluation of the

ecological effects of lead in dredged material, sediments, and industrial

wastes. The US evaluation demonstrated that a total prohibition of lead disposal was unnecessary and that lead-contaminated wastes could be adequately

handled through other provisions of the LDC. A very divisive and still

unresolved issue discussed at the seventh and eighth LDC is the possible prohibition of all materials containing low level radioactive materials and

wastes. This could be construed to include some dredged material. It is the

current US position that dredged material is nonradioactive for the purposes

* of regulation. The radioactive material issue will be resolved at LDC-IX in

September 1985.

The ninth meeting of the LDC (LDC-IX) in conjunction with the eighth

meeting of the Scientific Group (SG-VIII) made decisions on a number of issues

significant to dredging and dredged material disposal. Criteria for allocating toxic substances to the Annexes or even removing existing substances from

the Annexes were adopted unanimously by LDC-IX. These criteria now form a

sound scientific and technical basis for designating which substances need

stringent, moderate, or minimal regulation with regard to ocean disposal. It

was determined at LDC-VIII, IX, and SG-VIII that the Guidelines for Implementing Annex III were inappropriate for dredged material and in many cases tended

to unnecessarily overregulate dredged material. Additionally, several

technical/regulatory terms remain undefined that could if adequately defined

lead to a less complex and fractured regulatory scheme. Consequently, the

SG-VIII recommended and the LDC-IX approved an intersessional meeting of LDC

experts in dredged material disposal to develop specific Guidelines for Implementing Annexes I, II, and III for dredged material. This group will also

attempt to define terms such as "rapidly rendered harmless" and "special N• care.

The LDC-IX also approved, by roll call vote, a resolution calling for the

suspension of ocean disposal of low level radioactive waste (LLRW). The

resolution is one of principle and is not binding on the Contracting Parties -

to the LDC. It is important to note that the vote was based on almost purely . -

political reasons rather than on a scientific and technical basis as is called

for in the articles of the Convention. A proposal to amend the Annexes to ban

ocean disposal of LLRW was tabled for some future action. LDC-IX action on

seabed emplacement of high level radioactive waste was delayed until 1DC-X.

Intersessional groups meeting prior to LDC-X will discuss disposal of persis- .x~.

tent plastics, ropes, netting, etc., with a view of proper regulation and

incineration at sea.

The Intersessional group of T.DC dredging experts met in London 28-31

October 1985. The experts group agreed that specific guidelines for applying

all technical aspects of the LDC were necessary. Consequently, the group

241

%. %
developed and recommended for adoption by the LDC Scientific Group and sibh;equently to the Consultative Body "Guidelines for the Application of the

Annexes to the Disposal of Dredged Material." These are "stand alone" guidelines that incorporate previous LDC Annex guidance, modified as appropriate

for dredged material, and present a new section entitled "Disposal ManageMent dh el

Techniques." All previous LDC Annex guidance will have dredged material

references delected. The "new" Guidelines have exemptions and exclusions

appropriate to dredged material and discuss the acceptability of sea disposal

in relation to techniques to mitigate effects of highly contaminated material. V

The "new" Guidelines present a complete and holistic approach at managing the

disposal of dredged material in conformity with Annexes I, II, and III of the

LDC. Mortover, the "new" Guidelines recognize various disposal management

techniques that may be used to incorporate the "rapidly rendered harmless" and

"special care" terms into a disposal management strategy. These disposal

management techniques are considered to be any actions or processes by which

conformity with the LIC and the Annexes is achieved.

Future meetings of the LDC include the Scientific Group Meeting in April

1986 and the main consultative body in September 1986. Issues affecting

dredged material at the SC-TX include (1) review of Annexes with regard to

cadmium and lead, (2) sea disposal of dredged material, (3) clarificition of

undefined terms in Allocation Criteria, (4) field verification of predictive

laboratory tests, and (5) review of comparative assessments between sea disposal and land-based alternatives. LDC-lX will address the findings of SG-IX

and seabed emplacement of high level radioactive waste issues. Numerous other

nondredging issues will be addressed. Because of the significant importance

of the LDC to navigation and ocean disposal of dredged material, the Corps

will continue to maintain an active participation and leadership role in all

domestic and international aspects of the LDC with regard to policy and technical issues. Corps participation includes numerous interagency scientific

and technical working groups and committees as well as State Department

directed ocean policy groups. Continued Corps participation at these levels

will ensure that current research on dredged material and the Corps' vast

experience in managing dredged material disposal are integral to the ultimate

direction of the LDC.

FUTURE STRATEGY

In closing, there is a critical need to develop a more integrated

approach internationally and, more importantly, domestically to uses of the

ocean in general, and to waste disposal in particular. Demands on the ocean

from multiple sources (defense, fisheries, marine mining, waste disposal,

etc.) have increased significantly in recent years with a corresponding increase in conflicts between specific user groups. At present, regulation of

ocean uses is typically along generic lines, in some cases to the exclusion of

other potential users of the ocean environment.

In regards to dredged material disposal, the present domestic approach to

this disposal is medium-by-medium regulation. This approach results in the

protection of a particular medium for its use in waste disposal without regard .

for the impact of these regulations on other disposal media. Available

research clearly indicates that nc disposal alternative or media is withousome form of environmental constraint, nor does any one disposal alternative

or media reflect the best management practice or offer the soundest

242 2 4 2 Z >'9
environmental protection. It would seem far more appropriate to develop

criteria and guidelines that regulate the waste and not the medium to ensure "'.'

that all disposal alternatives are fully investigated and weighed during the

planning process and treated on an equal basis. It is imperative that a final

decision be made based on all available facts. The LDC is moving in this

direction, although somewhat laboriously, and the US must continue to maintain '5.

a leadership role in this area.

REFERENCES

Boyd, M. B., et al. 1972. "Disposal of Dredge Spoil; Problem Identification

and Assessment and Research Program Development," Technical Report H-72-8 US

Army Engineer Waterways Experiment Station, Vicksburg, Miss.

Brannon, J. M. 1978. "Evaluation of Dredged Material Pollution Potential,"

Synthesis Report I)S-78-6, US Army Engineer Waterways Experiment Station,

Vicksburg, Miss. .

(:Corps uf Engineers. 1976. "Ecological Evaluation of Proposed Discharge of

Dredged oi Fill Material into Navigable Waters," Miscellaneous Paper D-76-17,

I'S Army Engineer Waterways Experiment Station, Vicksburg, Miss.

Engler, R. 1. 1981 (Jun). "Impacts Associated with the Discharge of Dredged

Material: Management Approaches," Symposium on Engineering Aspects of Using

the Assimilative Capacity of the Oceans; National Academy of Engineering

Levees, Delaware.

Environmental Protection Agency. 1977 (Jan). "Proposed Revisions to Ocean

Dumping Criteria, Final Environmental Impact Statement," Vol 1, Washington,

DC.

EPA/CE Technical Committee on Criteria for Dredged and Fill Material. 1977.

"Ecological Evaluation of Proposed Discharge of Dredged Material into Ocean

Waters: Implementition Manual for Section 103 of Public Law 92-532 (Marine

Protection, Research and Sanctuaries Act of 1972)," US Army Engineer Waterways

Experiment Station, Vicksburg, Miss. *J. 5,

Federal Register. 1973 (Oct). "Ocean Dumping: Final Regulations and

Criteria," 38(198). A

Federal Register. 1977 (Jan). "Ocean Dumping: Final Revision of Regulations

and Criteria," Part VI, 42(7).

Herner and Company. 1978. "Publication Index and Retrieval System,"

Synthesis Report DS-78-23, US Army Engineer Waterways Experiment Station,

Vicksburg, Miss.

Lee, C. R., Engler, R. M., and Mahloch, J. L. 1976. "Land Application of

Waste Materials from Dredging, Construction, and Demolition Processes," Mis- %"%

cellaneous Paper D-76-5, US Army Engineer Waterways Experiment Station,

Vicksburg, Miss.

243

%5'

• .-". "-""-"-"" -""-"- -'-'- "" " -"-" * "S." "¢ . . '"" - - - "" "? - - -'"-'" '¢ " "-'"- - ". - "
Saucier, R., Calhoun, C., Engler, R., Patin, T., and Smith, H. 1978.

"Executive Overview and Detailed Summary: Dredged Material Research," Technical Report D-78-22, US Army Engineer Waterways Experiment Station, Vicksburg, eV

Miss.

244-
ANALYTICAL SURVEY OF ACCUMULATIONS

OF SEDIMENTS IN CANALS OF TOKYO PORT

Shinzo Kimura, Tetsuo Naganuma, Shin'ichi Wano '. .

Bureau of Port and Harbour . .

Tokyo Metropolitan Government (BPH TMG)

8-1, Marunouchi 3-Chome

Chiyoda-ku, Tokyo 100, Japan

ABSTRACT aThe canal beds around the Tokyo port are covered

with thick oozy sediments including floating sediments. These sediments often cause not only traffic

problems but also environmental problems. In order to

remove the sediments, a dredging project has been conducted. In order to perform the project effectively,

observations and analyses were carried out to identify

sediment characteristics, sediment sources, sediment

supply, and sedimentation rates.

The thickness of oozy sediments ranged from 60 to .-

80 cm, and the color of the sediments was black due to

the highly unaerobic conditions. The characteristic '.

values of bottom sediments, the water content, the

ignition loss and chemical oxygen demand, were about

200 percent, 10 percent, and 40 mg/g, respectively. .-

These values indicate that the sediments contain a lot

of organic substances. , .

To estimate the rate of sedimentations, samples

were collected in two ways, short-term (I day) collections and long-term (3 years) collections. The former .. >.,

method gave a considerably high rate of about 20 cm/

y-.ar, and the latter gave a lower rate of 1.5 cm/year.

However, direct observations of the sedimentation rate a-,

provided a range of 1.6 to 11.4 cm/year.

The major sources of the sediment are rivers

(48 percent of the total load to the canals), phyto- .: -- °d

plankton productions (37 percent), and sewerage plants

(15 percent). a.% -,

INTRODUCTION .r

As shown in Figure 1, the Tokyo port is located at the bottom of Tokyo

Bay and is the harbor at the estuary of the River Sumidagawa. It has played .

an important role as an import and export base for goods to support industrial .'- 4

activities and civil life for the past 100 years.

245
Si P

.°

Si--

39° 1330' 140 1430' 0

Figure 1. Location of Tokyo Bay .,-

Today, Tokyo port is a gateway for the metropolitan area of Tokyo, as ,,' well as for the eastern region of Japan. In addition, it has occupied a .

position as an international trading harbour which represents Japan. .

Canals in the Tokyo port are located at the boundary between the existing

town zone and the harbor. Most of these canals are artificial and were con- .. '

structed in the process of "reclamation" accompanying the enhancement of bar- ..

bour facilities. The total length of the canals is about 55 kin, the width 9

ranges from 30 to 200 m, the depth from 2.0 to 4.0 m, and the total area about

600 ha. Warehouses and shops which need canal facilities are built among the >.

*canals, and these places use lighters. Small vessels such as fishing boats, £'

monorailroad, 

passenger boats, 

highways, 

and governmental 

sewerage treatment 

boats are 

plants, 

also moored 

seawalls, 

here. 

marine 

In addition, 

parks, 

a I

, business offices, purposes.aand mansions Pdifferent are built; the canals are utilized for many -I

Techemical oxygen demand (COD) value, which is used to reveal the condition of the aqueous environment around the Tokyo port (the reference value

s below 8 ppm), had been lowered until 1980 through encouragement of various %,

environmental integrity actions, and thus water quality had been improved. In

1981, however, the COD value began to increase. Since that time, particularly In summer, the value often exceeds the reference value for water environment

246,.-. -,

Oi

ranges ft

60~ ha. Waeoue an shp-hc edcnlfclte r ul mn h
A major cause of the increased COD value is organic sediments on the

canal beds. Such sediments cause deterioration of the water quality, producing offensive odors, making people uncomfortable, and significantly lowering

their living environment. To eliminate these problems, since 1972 the Tokyo

Metropolitan Government has been engaged in gradually removing the sediments%

from the canal over a total length of about 40 km and a total area of about e

370 ha. This has resulted in considerable improvement of the environment

including prevention of offensive odors. However, because of the placement of

the canals and the existing sediment/water conditions, new sediment buildup is

occurring.

This paper introduces services performed in the Tokyo port for integrity

of the aqueous environment, as well as summarizes results of the site survey

performed since 1979 on properties of sediments, sedimentation rates, sources ,.

of the sediments, and sediment supply to the canals in order to encourage

sediment removal.

* OVERVIEW OF SERVICES

Our bureau is currently engaged in the following services in berths, sea

*passages, and canals to maintain integrity of the aqueous environment in the .

Tokyo port.

a. Sea surface monitoring. The port is always monitored by five patrol

boats to prevent illegal disposal of soil, dust, and waste oil and to

inform the agency of such illegal disposal.

b. Collection of waste oil from vessels. To prevent oil pollution of

the port, waste oil is collected from the incoming vessels by oil

collecting boats.

c. Prevention of oil diffusion. Seven oil treatment boats equipped with

oil fences are available.

d. Sea surface cleaning. Seven cleaning boats collect and treat floating dust in the port.

e. Treatment of sunken wood and bark. The circulation of logs handled

on the sea may produce sunken wood and bark. To prevent these from

being sedimented on the sea bottom and from adversely affecting the

water quality, the bark is treated through self-propulsive incineration boats and an on-land recycle center, by contractors.

f. Treatment of sunken and scrapped vessels. Sunken and scrapped

vessels left in the port are obstacles to vehicle passage and

adversely affect the water quality, and are therefore taken to a

disposal area for incineration, etc.

Removal of sediments at canals. Services are being performed to

remove sediments in the port, particularly in the canals:

247 '
(1) Plan: pollution prevention project in the Tokyo metropolitan

area (determined in December 1972 and revised for the third time

in March 1983).

(2) Performed in: 1972 to 1986.

(3) Amount of sediment planned to be removed: about 3.1 million

cubic metres.

(4) Amount of sediments actually removed: about 2.6 million m (1972

to 1984).

(5) Sediment removal standard: six-point estimation method (tenta- -..

tive standard). Ignition loss, COD, and sulfides are measured.

If any or the total of these values exceeds a predetermined

range, the sediments are to be removed.

(6) Method: Dredging: Pump type dredging boat, sealed type grab

dredging boat; transportation: Sealed type (box type) soil

transportation boat, bottom opening type soil transportation

boat; disposal to treatment plant: Pump type sediment raising

method, secondary sediment feeding method.

DISCUSSION

Characteristics of Bottom Sediments

Stratification of Sediments

Sediments were sampled at station B-I through B-5 as shown in Figure 2.

Over the entire canal, the thickness of the sampled sediments was about 60 to

80 cm, while the thickness of sediments sampled at the Koto district was 40 to ". -

70 cm. The thickness was lower here, indicating obvious layer divisions not

observed at the other stations.

Irrespective of the sampling point, the color of sediments was black;

this indicates that sediments in the shallow sea are significantly organically ,N \

polluted. The sediments are black due to a combination of Fe2 with hydrogen

sulfides formed by decreased oxidation-reduction potential.

Except for Shibaura (St. B-2), gray-green to dark-gray layers 3 cm thick

were observed at the surface section. The layers seem to have been produced in winter because water masses were mixed and thus bottom water became

aerobic.

Characteristics of Sediments

Table I shows the results of analyzing the sediments discussed above. A

distinct odor indicated the presence of hydrogen sulfides at all stations except Harumi (St. B-3). Water content ratio was not less than about 200 percent at all stations except Koto (St. B-4). Wet density was not greater than

3 about 1.3 g/cm , ignition loss, COD, and total organic carbon (TOC) as indices

of organic pollution were over 10 percent, 40 mg/g, and 20 mg/g, respectively,

248 ~~ ~ rY6.

9
KOTO D ISTIR ICT ~

Nomama C Su9-4n S wg

- . tomI C. I Treat enT PI ont

~ M-4

I ___Berin

Sibaura Swg

< Treatment ln hnnm~tc

< Takahamra C,

i Tn-nosu C. BMp.atR. M-5 V

U

zC

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Fiur 2. Sttinoctin

-. .. p 5 -. .249
TABLE 1. VERTICAL CHANGES OF SEDIMENT CHARACTERISTICS

Sediment Station

Items Classification B-i B-2 B-3 B-4 B-5

Hydrogen Hydrogen Odor A* None None None sulfide sulfide

B** Hydrogen Hydrogen None None None

sulfide sulfide N"oe

Ct None Hydrogen sulfide None None None .-

Water A 184 720 215 283 232

content, B 251 625 178 108 199

percent C 140 502 154 80.8 253

Wet A 1.27 1.06 1.23 1.17 1.22

densitv, B 1.20 1.07 1.27 1.43 1.24

g/cm3 C 1.35 1.08 1.31 1.56 1.19

Ignition A 11.2 30.8 13.0 13.6 11.1

loss, B 14.1 31.7 13.0 7.2 12.1

percent C 9.7 30.4 12.1 5.9 15.5

COD, A 38.8 125 50.0 43.7 49.1

mg/g dry B 54.5 114 51.6 16.6 55.7

C 32.7 119 40.4 14.0 71.0

TOC, A 26.3 104 30.2 21.8 21.8

mg/g dry B 35.7 113 30.3 15.3 24.7

C 18.6 101 26.5 12.2 37.7

Sulfide, A 8.57 9.90 3.18 4.80 2.85

mg/g dry B 2.17 8.30 6.41 0.57 3.93

C 3.55 11.1 3.78 0.50 8.23

Sampling period: December 1979.

* Very high water content sediment, partially oxidized layer, found in top

3-cm layer.

** High water content and reduced sediment.

t Low water content sediment.

25.0. ,

• i*TY.

, 9 

v ". "..'.''-' ,' . .Ii.-"- .' %%., '-" " '- .% - ', V-" - " "-"•"-"-'""-'•"
* % •

each indicating high values and revealing the progression of organic pollution

in the sediments in the canal. Sulfates showed a high-value of about 3 mg/g

(dry sediments) except for Koto; the black sediments may be due to sulfides. ".IF

The sediment analyses showed that the water content ratio of the sedfments sampled in Shibaura (St. B-2) was high (500 to 700 percent), the index

of organic matter was high, and the sediment was polluted organically. The .

canal of Shibaura is located inland and is narrow; the organic matter produced

here or discharged from the sewerage treatment plants will probably settle in

the canal.

Characteristics of

Sediments and Sedimentation Rate

Qualitative and quantitative measurements have been made both daily and

annually of the canal bed sediments.

Short-Term Measurement

Using Polyethylene Bottles

One-liter polyethylene bottles as shown in Figure 3 were installed 1 m

above the canal bed to sample material sedimented for I day. Table 2 shows

the results of this sampling. The amounts of material were high in Keihin

(St. B-i) and Sunamachi (St. B-5), and low in Koto (St. B-4) and Sunamachi

(St. M-2). A comparison of these values was made with values observed in

Funka Bay from summer to fall (Handa and Tagami 1981), in Tokyo Bay during a

red tide (Sato 1977), and in Kizaki Lake (Koyama 1980). This comparison

showed that the same amount, or more material settled during the red tide in

Tokyo Bay as in the canals of Tokyo Bay, depending on the measuring point.

Table 3 shows the sedimentation rate calculated from the amount of .- '.

material sampled using the polyethylene bottles.

Marker buoy - -"""

V...%°

Bottom Weight Anchor

Polyethylene surfce.

bo ! t le T '-'-,!,' . ... /'- / /. ' ''

Side view of the sampler V,.,,"

Figure 3. Sediment trap and mooring method

)! (SpedV 

Top *-n, iew of te stinpier(Poyetylen bofiq

Bottom~V nco Wegh Poletylne 251 ac
.'9

TABLE 2. AMOUNT OF MATERIAL (g/m2 /day) COLLECTED

BY THE POLYETHYLENE BOTTLE 6.0

Period of Station

Sampling B-1 B-2 B-3 B-4 B-5 M-1 M-2

December 1979 241 124 (454)* 33.8 286 136 60.4

January 1980 326 160 138 34.6 252 117 63.4

* The value in parentheses seems to be influenced by ship propellers.

TABLE 3. BOTTOM SEDIMENTATION RATE (cm/year) ESTIMATED

FROM THE AMOUNT OF MATERIAL COLLECTED

Period of Station

Sampling B-I B-2 B-3 B-4 B-5 M-l M-2

December 1979 19.7 35.0 42.5 4.0 28.4 13.5 6.0

January 1980 26.6 45.2 12.9 4.4 25.0 11.6 6.3

* The rate of sedimentation is calculated by the following equation:

1 100+ W h =s x x 00 x 365

where

h = Bottom sedimentation rate, cm/year

s = Collected amount, g/cm2 /day

p = Wet density, g/cm 3

w = Water content, percent

The value of p and w were shown in Table I (very

high water content sediment). #

The calculated rates of sedimentation are considerably higher than both

the results of the previous survey and the direct measurement in this survey.

252

9
_I

Long-Term Measurement

Using Canvas Buckets

As shown in Figure 4, 12 buckets were placed immediately above the canal

beds to collect material. These buckets were retrieved one by one at 3-month I

intervals from 1979 to 1981.

Steel s loppe6rbar Sediment trap

11) I n oe (Canvas bucket)

Canvas bucket Subsurface buoy

50cm Anchor

150cmi

Eyelet(1) Placing 12mm0

27.7 ~Unt:cmn Btom Cna bucket

77--7 4 m7 ?7~7 (2) Retrieving

lS~crn% '..'

Figure 4. Sediment trap and placement method

Table 4 shows the sedimentation rates estimated from the water content

ratios, wet densities, and amounts of material measured at stations in the I

Koto District.

" TABLE 4. CHARACTERISTICS OF SEDIMENTS COLLECTED BY THE LONG-TERM

TRAPPING EXPERIMENT AND SEDIMENTATION RATES DERIVED

Station (Koto District) ""

Item B-5 M-I M-2

Water content, 296 159 237

percent

Wet density, 1.17 1.25 1.19

g/cm.

Collected amount, 15.5 18.7 15.5

g/m2 /day -6

Sedimentation, 1.9 1.4 1.6

rate, cm/year "d'-

Trapping period: December 1979-December 1981.

253

%~~~ % %% 

"---
The values of ignition loss, COD, and TOC as indices of organic matter

tend to decrease as the sampling period becomes longer. Characteristics of

sedimentations collected in an earlier period were similar to those of suspensions in the water. On the other hand, settlings collected later were similar

to bottom sediments.

Direct Measurement

of Sedimentation Rate

In general, the rate of sedimentation is measured using radioactive nucldesincluding 14C n 210p -

nuclides C and Pb as the tracers (Matsumoto 1975). Lately,

organic chlorides such as PCB stable in the atmosphere have also been used as

tracers (Aizawa 1975). However, methods using tracers can be applied only to

seabeds with very slow bottom flow and are not adapted to the water areas,

like the canals of interest, with violent agitations caused by dredging and

floods. In our case, stainless steel reference plates were placed about 10 cm

below the canal bed, as shown in Figure 5, and the rate of sedimentation was

determined on the basis of the plates from aging of the thickness of

sedimentations.

Steelsrfc Yi

stopper

(1) Structure (2) Placement

Figure 5. The measuring method of sediment thickness

using a stainless steel plate

Since the canal waters were highly turbid and dark, it was difficult to

directly measure the thickness of sedimentation on the plate. Divers sampled

sedimentation at three positions on the reference plates using three acrylic

transparent tubes (having an inside diameter of 3 to 5 cm), and their thickness was measured on a boat. Figure 6 shows the changes with time of the

thickness of the sedimentation, wherein the maximum value of the thickness is

regarded as the actual thickness of sedimentation. The sedimentation rates

determined 

rate of sedimentation, 

from the 3-year-long 

which is 

experiment 

affected by 

were 

the local 

1.6 to 

characteristics 

11.4 cm a year. 

of 

The 

each

.

canal, is considerably different depending on the measuring point.

254

% % ..

. ,-.. . .- - - ." ,' . " . . .
~- , .- - !- , :,W -. * j . -- ' -v W~. W.'Z '.- W '. 5. -- WVW. V '.. 7. i W '. I V .W ~ tWV VW ~W VW WV V'r W'. .

3-0

.y y 3

.

6

4 X t5 5 R.S

20 _ .-- -- - fr:0 r. 937)

to- St M-4

0 * ; 1981 1982 ;983 1984Il

3 0

F

4 Y-13.0 X I.l 7 4 X

30- lr'0430) f (r0,730) r: 

to 1 St M-5

-3o 10 1 2 1983 19,184, ,.y:19.0 X+I0.5

b' • 

( r-zO.974) . . . . 20-" y1 55 X921 I

o-St. M-6 (r:0.747) .

180 1981 982 983 1984

Figure 6. Changes with time of sediment %

thickness on the plate of stainless steel (Shibaura District)

Comparison of Methods to

Determine Sedimentation Rates

Table 5 shows the values determined from the three measuring methods:

stainless steel plate, canvas bucket, and polyethylene bottle.

TABLE 5. COMPARISON OF BOTTOM SEDIMENTATION RATES (cm/year)

OBTAINED FROM THE THREE METHODS*

Station

B-i M-4 M-5 M-6 B-3 B-4 B-5 M-1 M-2

Method (B-2) Remarks

Stainless -- 3.6 11.4 1.6 .. .. 3.8* .. .. Observed

steel plate

Canvas .. .. .. .. .. .. 1.9 1.4 1.6 Calculated

bucket

Polyethylene 23.2 .. .. 40.1 27.7 4.2 26.7 12.6 6.2 Calculated , bottle

* Observation period: August 1980-August 1981.

255 7

-r . .". 7
* = w a - S S - .-- 

From Table 5 it can be seen that:

a. The rate of sedimentation measured at the same measuring point is I

significantly different depending on the measuring method. The rate

of sedimentation measured using the stainless steel plate is 1.6 to ,-. -

11.4 cm a year.

b. The rate of sedimentation calculated from the value measured using

the polyethylene bottles is 4.2 to 40.1 cm a year, which is about

three to four times higher than the results of the direct measurement. The former seems to ignore decomposition of organic matters

and resulting consolidation of the sediments.

c. The rate of sedimentation calculated from the value measured using

the canvas buckets is 1.4 to 1.9 cm a year. This value, as it has

been determined from data obtained over an observation period of

2 years, is near the value corresponding to the actual rate of

sedimentation.

Sedimentation Rate Determined -

from Previous Water Depth Measurement .. -.

For comparison, the sedimentation rate was determined by water depth

measurement performed in 1979 and 1982. According t, this depth measurement,

the rate of sedimentation around Showa Jima, where Morigasaki sewerage

treatment plant is located, was 13 to 17 cm a year. .".-'0J

In the water area round the Shibaura District, which is almost enclosed 4

and which receives disposal water from the Shibaura sewerage treatment plant,

the rate of sedimentation was 4 to 10 cm a year. Before 1978, a high rate of

sedimentation of 32 cm a year had been estimated at a Shinshiba canal.

At Toyosu, Harumi, and Asashio canals located at the estuary of the River

Sumidagawa, the rate of sedimentation was 16 to 23 cm a year. In Koto and

Sunamachi Districts, the rate of sedimentation at Shiohama, Shiomi, and

Shinonome-Kita canals was 0.7 to 14 cm a year.

This comparison of sedimentation rate indicates few differences between

our value and the value based on water depth measurement.

Sources of Sediments and Their Supply -=-

The thickness of sediments on the seabed is increased by suspended solids

(SS) (hereinafter referred to as settlings) existing into the water and produced within the water. There are three major sources of sediments: discharged from sewerage plants, river runoff, and phytoplankton production in

the water. These three factors are discussed below along with the sources of O.N

material by water area. a.

Sewerage Treatment Plant

In the canals of the Tokyo port, there are three sewerage treatment

plants: Morigasaki, Shibaura, and Sunamachi. The amount of material

256

%I -.5!

• .5'%
discharged from the sewerage treatment plants has decreased from 4,700 tons a

year in 1980. However, BOD loads to the sewerage treatment plants and the

amount of treatment water have not changed.

The sewerage plants treat both the public sewerage and the drainage basin

sewerage. This means that when a large amount of rainwater flows into the

plants, the untreated sewerage is discharged directly to the canal.

The amount of material produced due to overflow from the sewerage treatment plant into the canal must be identified. According to preliminary studies of the untreated loads and studies done in the United States, the SS loads

are about 15 times as high as the treatment water (Hoshikuma 1982). Hence,

the amount of settlings originating from the sewerage plants and discharged

into the canal has been estimated to be about 80,000 tons a year.

River Runoff

Six rivers, Sumidagawa, Furukawa, Megurogawa, Tachiaigawa, Uchikawa, and

Shin'nomikawa, flow into the canal sections of the Tokyo port. In contrast to

a large river, the small river with a short length and small basin is characterized by sudden increases in discharge and wide variations in discharge.

The discharge during rainfalls is much greater than the discharge during sunny

weather; in particular, the discharge during a heavy rainfall is greater by

several orders of magnitude. This also applies to the rivers which flow into

the canals in the Tokyo port; while the amount of material which flows from

rivers into the canals during a heavy rainfall seems to occupy a great proportion of the overall material, no data have been obtained which indicate a correlation between discharge during a heavy rainfall and change in water

quality.

A report about characteristics of SS-loaded discharge during a heavy -"

rainfall measured at Yabata River (which is located at a crowded place in

Toshima Ward) reveals that the SS load is proportional to the square of the

discharge (Yamaguchi 1977). The amount of material carried by the rivers into

the canals has been estimated to be about 250,000 tons per year on the basis

of the above report, 85 percent of the amount resulting from heavy rainfalls.

The amount of sediments on the river beds flowing into the canal was N,

estimated to be about 600,000 cu m by our survey; some part of these sediments

flow into the canal during heavy rainfalls.

Phytoplankton Production

Eutrophication of the water leads to a large phytoplankton production and

seems to result in shallowing the canals. Red tides (abnormally high production of phytoplankton) occur every year in Tokyo Bay, which includes the Tokyo

port. To what extent the plankton productions contribute to the shallowing

needs to he investigated. To estimate potential settlings due to plankton

production, observations were made in 1981 at the eight stations shown in

Figure 2.

Measurement of dally phytoplankton production using an in situ bottle

method has shown relatively high values in summer in some canals and passages

*- and very low values in winter at every measuring point relative to summer.

' "" 257 .

29 2 *

-*

***,.*f*-*..*-**-*-.** .. *- - . . . . . .
From the results of surveying the amount of phytoplankton production, the

amount of production per unit area was calculated, which was then multiplied

by the water area of the Tokyo port to determine the amount of produced or- e

ganic carbons over the entire area. The amount of phytoplankton production

has been converted from the amount of produced organic carbons by regarding

their chemical composition as following the Redfield's model. ,..e

Thus, the amount of produced organic carbons in the Tokyo port originating in phytoplankton has been estimated to be about 50,000 tons a year, and

the SS amount becoming settlings on the bed at about 190,000 tons.

Then, for the canal, unsteady phytoplankton production during a red tide,

etc., must be examined. The amount of net production during red tides in

Tokyo Bay has been estimated to be 12 to 57 g 0 M/a. Thus, by applying '

the above-mentioned calculation, the amount of material settling due to phytoplankton in 1979 (during which a red tide occurred frequently) has been estimated at about 270,000 tons, which is about twice as many as that in 1977

(during which fewer red tides occurred).

Sources of Settlings by Water Area

Figure 7 shows the relationships between TOC and chlorophyll contained in

the sediments.

Canals in Shibaura District

40 

" .

Canals In other -"

parts "

30 - Berth and

- passage areas

0

- 20

10

0~

0 50 100 150 200 250

Chlorophyll-o + Pheophylin (.ugjg)

Figure 7. Relationship between TOC and photosynthetic pigments in the bottom sediments and their changes with region e-.,

The relationship, by water area, between hlorophyll and TOC in the sediments has shown that TO(C increases at a certain rate with the increase of

chlorophyll, although the ordinate intersections are different by water area.

This indicates that the loads ot allochthonous organic matters are different.

depending on the measuring point and organic carbons ori ,iniiting from

.-. ~ .. .. . . . . . . . . .

, , •,- , ,, -•.,, • , , • .. , ,. , , . . . . , , .. ... - . . . . . . . . •,
phytoplanktons loaded on the sediments. For the canal, the rate of contribution of the loads is different by water area. The paragraphs below discuss

the sources of settled material by water area estimated from positions and

water quality.

Around Showa Jima in the Keihin District, where the Morigasaki sewerage

treatment plant is located, are the rivers Ebitorigawa, Shin'nomikawa, and

Uchikawa, and Ebitori canal. While an attempt to investigate the sources of

sediments in the water area was made, the contributions of the rivers, the

sewerage treatment plant, and phytoplankton production could not be identified, though these three factors must contribute to sedimentations in a complex manner.

The water area in the Shibaura District, which is surrounded by Takahama,

Shibaura, and Shin-shiba canals, is highly closed. There is a sewerage treatment plant in the district which affects sedimentations significantly, phytoplankton production contributing very little to the sediments. The water area

around Ten'nosu canal is affected considerably by Megurogawa River.

The water area around Tsukishima and Harumi, which consists of Harumi and

Asashio canals, is affected significantly by the River Sumidagawa, but phytoplankton production cannot be ignored.

.

Shiomi, Shiohama, and Shinonome-Kita canals in the Koto District are

affected significantly by phytoplankton production. Near the Sunamachi canal,

belonging to Sunamachi District, is Sunamachi sewerage treatment plant; phytoplankton production cannot be ignored, but estimating the material settled is ,J.

difficult since the water flow is high.

As described above, the source of the sediments differs depending on the

causes and places, and thus cannot be discussed together.

Estimation of the Amount of "-",

Settlings Applied to Tokyo Port

The SSs that come into the Tokyo port (inside a central breakwater)

including canals, berths, and passages originate from sewerage treatment

plants, incoming rivers, and phytoplankton production, and their amount varies

significantly between steady and unsteady (heavy rainfall, red tide, etc.)

conditions. A rough estimation of the thickness of sediments from the amount

of settlings supplied to the whole Tokyo port leads to the following results:

a. 520,000 tons of SS are sedimented a year in the whole Tokyo port.

b. 48 percent of these originate from rivers; they are carried into the

port particularly during heavy rainfalls.

c. 37 percent of the SS originate from phytoplankton production; this *-..,

ratio tends to increase in years during which red tides occur

frequently.

d. 15 percent of the SS originate from sewerage treatment plants, which

affect the near canals significantly.

259 "'..-

% . --

, ..'£, ". . ...., ... . 2,%,'_ .,°. "... ..o '

.,- , ., ... , ."...' ., .I ..
The yearly SS have been converted to the corresponding volume, which has

then been divided by the water area of the whole Tokyo port to estimate the

mean rate of sedimentation. The result was about 6 cm a year. This value

closely approximates the values measured by the stainless steel plate method

(1.6 to .4 cm, mean value of 6.5 cm a year), and thus seems to be appropriate. The mean value (about 6 cm a year) is based on an assumption that

every loaded SS has been sedimented on the bed of the whole Tokyo port. As

the loaded sources contribute differently to settlings depending on the water

area, applying the mean value directly to the object of design as the rate of

sedimentation for the water area is accompanied by a number of problems yet to

be solved.

CONCLUSIONS

The degradation of the environment in closed waters such as canals and

inland bays is caused by loads from lands and by red tides occurring in the

waters. It has been pointed out that sediments on the beds of the rivers and

the sea significantly affect this degradation. The effects of sediments on

the water area include offensive odors, rolled up dirt, consumption of dissolved oxygen, and release of COD components and nutrients.

Based on this background, our bureau is engaged in sediment removal to

restore the aqueous environment of the canals. Since sediments have been observed to resettle after removal, our bureau performed this survey to understand the characteristics of sedimentation in the canal and to encourage

sediment removal.

This survey, performed for the first time in Japan, has led to an understanding of Lhe characteristics of the bottom sediments and of the rate of

sedimentation, and to the identification of the sources of the sediments and

the amounts. However, this survey revealed that the sources of sediments are

different for different canals; conditions such as heavy rainfalls and red

tides produce significant effects; and it is difficult to quantitatively

identify settled materials and sediments. Investigations will continue in

order to solve these problems.

While this survey has aimed at determining the amount of sedimentation,

the effects of sediments on water quality must be identified quantitatively y.

before the water environment of the canal of the Tokyo port can be restored.

A survey for this purpose began in 1983 and will end in 1986.

Through understanding sediments both qualitatively and quantitatively,

our bureau aims at revising the current tentative removal criteria and including the revised criteria in the next pollution prevention plan (prepared in -

1987) to establish a commercial entity for such plan implementation.

REFERENCES

Aizawa, Takako. 1975. "Cadmium, Total Mercury and PCB on Beds of Tokyo Bay,"

Report of Research for Restoration of Bottom Quality in 1974 (in Japanese).

Handa, Yasuhiko, and Tagami, Eiichiro. 1981. "Process of Perpendicular

Transportation of Organic Matters in Funka Bay," The Process of Settling and

Sedimentation in Bay and Coastal Region, Japan Fisheries Resource Conservation

Association (in Japanese).

V. 260
• " " " ""-,.--p

Hoshikuma, Yasuo. 1982. "Combined Sewer System and Water Pollution Control,"

Journal of Environmental Pollution Control, pp 327-330 (in Japanese).

Kovama, Tadashiro. 1980. Biological Earth-Chemistry, Press of Tokai

University (in Japanese).

Matsumoto, Eiji. 1975. "Rate of Sedimentation at the Bottom of the Lake Biwa ,

210 \

by Pb Method," Journal of Geology, pp 301-306 (in Japanese). . ' 'U

Sato, Yoshihiro. 1977. "An Inquiry into Form of Sediment Trap Used in Bay,"

The Process of Settling and Sedimentation in Bay and Coastal Region, Japan

Fisheries Resource Conservation Association (in Japanese).

Yamaguchi, Takashi. 1977. "Problems of Water Pollution in Urban Rivers,"

Journal of Water Quality of Japan's Rivers and Streams, Japan's River and

Stream Association (in Japanese).

261 .,

."4 %

:.4.-..

':I.)

,.-..--..-- ..... ....-..... 

* 4. . ... . ..... ....- ..... .... - .
II

TECHNIQUES FOR MONITORING STABILITY OF OFFSHORE

SUBMERGED DISPOSAL MOUNDS

Edward B. Hands

Coastal Engineering Research Center

US Army Engineer Waterways Experiment Station

P0 Box 631

Vicksburg, Mississippi 39180

4, The physical fate of dredged material released in the marine environment

often is of vital concern. If currents spread the material beyond the disposal site, problems could arise, such as shoaling of adjacent channels or

smothering of biological resources. In other instances spreading may be

desirable, for example, to increase site capacity, nourish adjacent beaches,

or simply return the material to the natural system from which it was

* captured.

In addition to site-specific questions regarding sediment migration, it

is crucial to obtain good field data for verification and calibration of

numerical models so that rates and directions of spreading can be predicted

for various conditions. Such predictive ability would lead to design criteria

to minimize problems and maximize beneficial uses of dredged material.

Several standard geophysical techniques are presently available to

provide needed basic field data. A few new tools offer promising potential to

augment today's techniques.

Hydrographic surveys can document changes in the shape of any substantial

sediment accumulation. Subbottom seismic reflections can reveal subsidence of

the foundation beneath the accumulated materials. Side-scan sonar surveys

record the surface characteristics across wide swaths of the bottom, and can

be used to identify and map edges of disposal deposits which are too thin to

be recognized on sounding or seismic profiles. Sediment samples allow direct

examination that may include sedimentary, chemical, or microscopic analysis to o

* confirm subtle distinctions between disposal and native bottom materials.

Sediment cores provide stratified sequences that record layer-by-layer accumulation and compaction within the deposit. Cores can also indicate where currents or organisms are reworking or mixing the different sediment types.

In addition to these surface-operated techniques, the observations of

technically trained SCUBA divers greatly increase our understanding of bottom

* characteristics and our confidence in the interpretation of more expansive,

remote techniques. Repeated measurements by divers of the bottom elevation

will indicate accretion and erosion independent of, and on a different scale

from, that captured on sounding records.

The foregoing techniques use readily available equipment. New technology

offering potential for monitoring disposal deposits includes (1) swath sounding systems that, from a single pass, reveal a three-dimensional picture of

the bottom; (2) seabed drifters that move with the bottom currents and indicate where moving sediments may accumulate; and (3) sediment traps that canl be

used in conjunction with current meters to quantify sediment movement. If the

26-1

% h% Nk9
disposal depth or other conditions preclude direct observation by divers, .

remotely controlled television or photography can still provide a view of the ..'.

bottom. A newly developed camera system photographs even the sediment-water

interface in cross section using a lens prism that penetrates the upper few

centimetres of sediment. All these techniques depend, of course, on good

positioning.

Incorporating the discussed elements in an efficient monitoring plan

depends on familiarity with the capability and requirements of each element. "-%.-

Because of the usual demands and expense of working at sea and the challenge

of distinguishing native from disposed material, as many of these overlapping ?...

techniques as possible should be incorporated into any survey plans. Mobili- . -

zation and boat time are major cost items. Thus, multiple element surveys .

often provide not only the best insurance of success, but also the most '.

cost-effective approach for tracking disposed material.

2-6

.;..:....:

... '. ",d,.
-- -- - - - - - - - .

s.'.

USE OF ANTI-TURBIDITY CURTAINS AT A

SAND COMPACTION PILING AREA IN YOKOHAMA HARBOUR

Rin Hatano, Yasuo Abe

Japan Bottom Sediments Management Association

ABSTRACT

Sea work, such as dredging and sand compaction

, piling, causes turbidity in the surrounding sea area.

To prevent diffusion of turbidity, anti-turbidity

curtains are generally used in the working area. In

such cases it is important to know how the curtains

affect suspended solids in seawater. In 1984 antiturbidity curtains were used at a sand compaction work

area in Yokohama Harbor, and the behavior of suspended

solids around the curtains was observed. This paper

reports the data measured at that time. ..*.

CURTAIN APPARATUS

There are two kinds of anti-turbidity curtains, continuous and jointed.

The continuous type requires a large space for assembly on land and much work

to place it at sea (Figures I and 2).

Compared with the continuous type, the jointed type requires a minimum of

space for assembling and erecting (Figure 3). -%

Fiur 1.: Asebig nhr

264

Z ..

Figure 1. Assembling onshore

264--+-.

-5* , p+ ,m . "- + ' " '++. ',.. ++,#,.,.,.P_'..._ .%** + ' . -.,J ., -. ',. " ,.+.,'_' ... -. . . -+. . 1
..-

Figure 2. Transporting from shore ::..

A

Figure~~- 3. Asemligflot

£ • •. o..- .*

- .•.,

The jointed type can also be placed at sea by connecting the elements. .... The 

mercial 

jointed a ntti-turbidity curtains in our country are called by the com- '''' name "Patoresia." The apparatus used in Yokohama Harbour is indicated "" in Figures 4 and 5. 

"(

BACKGROUND OF WORK SITE °'...

The City of Yokohama's reclamation project, "Harbour Future 21," began in" ', February 1984 (Figures 6 and 7). .

265 

' ,.

% ... . .. . . . .~ % -
.. W

Patoresia P-2

1 480 !. X 48M xn A= 2D 0 L 1... 

* 

_ l;ii i i : 

___ ____ - flfl I

Figure 4. Appearance of curtains

'E

Figure 5. Aggregate of curtain apparatus

The land to be reclaimed has an area of 76 ha and after completion will

be utilized for port facilities, international cultural exchange facilities,

park and green spaces, etc. Figure 8 shows an anticipated view of the new

port area when completed. The sand compaction piling is used to stabilize the

bottom sediment at the reclamation area.

MEASURING SITES %

The suspended solids (SS) concentrations near the anti-turbidity curtains

were measured at two different locations on February 3 and May 21, 1984. The

measuring sites are shown in Figures 9 and 10.

Figure 11 shows the work area surrounded by curtains.

Flow velocities and directions as well as SS concentrations were measured.

From these it was found that a reflection wave occurred (Figures 12 and 13). ,

It is natural that there is no pulsating wave at the lower layer underneath the curtains and outside them. The tide velocities were about

10 cm/sec. The Froude number of the pulsating wave was F = 0.0056 .

266

.%"

9
-J.

'J% %~

...... . . . ' 

%U %*

Figue prject"Harour 6.Reclmatin utur 21

Figure7. sit Wok 

267
NaIV..

Fi 8. ur A t c p te i w okcm l t o

N o

Figue sit 9.Measrin of ebrury

268.
. %*

Figure 110esrn it fMy2

269 

'
J^

4-1a

Figure 12. Reflection curve

cm/sec

Upper Layers

0

Scm/sec Curtains

0 "Middle Layers

09

O ,'.'- A

Figure 13. Pulsating wave reflected by curtains

RESUSPENSION COLUMN

At the sand compaction point some amount of sediment particles are

resuspended upwards by the turbulence (Figure 14). In this case movement ofg

Resuspension %

H Column Figure 14. Turbulence

resuspension

Turbulence

%

27..

'-(., :: - " ' .dt.. _ - ,-: ' -- "- "-" ". S""? ,"'"',., - , '''"270 , ".'' , .""" 9"-""""- 

" " .
the resuspended particles is represented as follows (tide velocity neglected):

Kz TZ- Ws = 0 (1)

where

Kz = diffusion coefficient in the vertical direction

c = concentration of resuspended solids

Ws - mean settling velocity of resuspended solids

The solution of Equation I is obtained as follows:

Kz Kz 1 .

C =A -s e + B (2)

One of the boundary conditions is Z = 0 ; C = Co.

B Co A Ws WS i

Then we have .

K z Z

C Co + A s (e

The other condition on the sea surface is

Z 0; -WsC + Kz = 0 az

Then

-_ 6%

A = Co Kz

271

*' '.5 -;:v ** .** .*.,*-**- * .S *,, S. .. *. ?WW.r\,',' 45U .t I v , .... * ,:.-*" v. ."',V:..
Finally, we have ,,,,.

.,

Ws 

t

C = Co e z(3) 3

Equation 3 indicates the resuspension column has a vertical distribution

with an exponential form. t,

Figure 15 shows two vertical distributions of the resuspension column

obtained on February 3 and May 21, 1984. The SS concentrations at the turbulence points were 900 mg/i and 1,100 mg/t, and the ones at the sea surface

(H = 0.5 m), 26 mg/i and 140 mg/i, respectively. Both vertical curves clearly

have exponential form.

SS Concentration

0 _P

2

D4 U

4-''

8 ..-. :

,..-.

S6

F 3

8 . May 2 -'-

Figure 15. Resuspension column, May 21 and February 3

When we plot the data of May 21 on half-exponentially graduated paper, we

have a curve consisting of two straight lines as Figure 16 shows. For the -

upper and lower halves we have

WsJ

z= 0. 1418 1/m

Ws2 '"

-= 0.3818 i/m

272 ",4
Then assuming Kz =2 cm2 Isec, we have%.%.

Ws =2 x 0.1418 x 10 - 0.002836 cm/sec

2Ws 2 x0.3918 x 10-2= 0.007824 cm/sec

Using Stoke's equation

2 1811Ws U (Ps- Pw)

We can obtain the mean diameters of the resuspended particles:

2 18 x 0.01 x 0.002836 3.5 7 %

1 980 (2.6 - 1.03) c

d =0.57 x 10~ cm =5.7 P'

d2 18 x~ 0.01 x 0.007824 =8.982 x10-7 cm2

2 980 (2.6 - 1.03)

d =9.48 x10- cm4 9.5 P'

2

ncr

2-

3

4-

5 Figure 16. Resuspension column,

February 3 .

6

7A

Feb. 3

273

-. - - - .- -. . . . - .- -.- . . r2
From the data of May 21, we get 2 particle diameters di = 6.54 P and

d2 = 8.02 P by the same way. From these data, it is found that the resuspension column consists of two particle groups having a mean diameter of

5.7 - 6.5 P at the upper layers and 8 - 9.5 p at the lower layers.

0'. 7,&"%

L-.." 0

2-

6

May 21

8,

Figur colun, Ma 10 100 low

SS Concentrations mg/

Figure 17. Resuspension column, May 21 ,

SEDIMENTATION PROMOTED BY CURTAINS iN

". ,Stagnation 

/

U

Ux :-'

Downward vel.

Component Uz

Inside the curtains, where the horizontal tide flow collides with the

* curtains, a stagnation flow is generated. Suffering this potential flow, the

seawater flows downwards and underneath the curtains. Meanwhile, the suspended solids contained in the seawater settle rapidly. The change in SS

concentrations influenced by the curtains is represented as follows:

c c 2 c S

-+ Ux T- + Kx - + Kz (4)

where

274%

A. .
c = concentration of suspended solids

Ux = horizontal flow velocity component of tide

Uz = vertical flow velocity component of tide S".,.

Ws = mean settling velocity of SS particles

Kx = diffusion coefficient in the horizontal direction

Kz = diffusion coefficient in the vertical direction

The turbidity soil particle with a 10-p diameter has the following settling

velocity:

Ws - s- Pw gd2

18 g

=2.65 1.03 x 980 x (0.001)2

* 18 x 0.01

= 0.009 cm/sec

With a tide of 10 cm/sec, the downward flow velocity component can be

taken as follows, when the inclined flow inside the curtains has an average

of 50.

Uz = 10 sin 50 = 10 x 0.087 = 0.87 cm/sec

Then we have

Uz + Ws = 0.87 + 0.009 = 0.879 cm/sec

Therefore we obtain the following magnification

vertical vel. component with curtains

vertical vel. component without curtains

Uz + Ws 0.879

Ws 0.009 *98

This means that the curtains increase the settling velocity of the

turbidity soil particles by about 100 times. In other words, the function of

the curtains can be regarded as increasing the particle size of the turbidity

275

*0%
N -

.- -k.-

soil particles by '100 = 10 times, compared with the soil particles without

curtains. In such a way the curtains play an excellent role in promoting the

* sedimentation of suspended solids. Figure 18 shows the change of SS concentrations inside the curtains.

Feb. 3,1984 Curtain

,N IN

2

a.,' 4 7)

6 Q9Np

10 -

121

130 m 100 50 20 5 10 30 50 lOOm

Distance from the Curtain

Figure 18. Change in SS concentrations inside curtains, February 3, 1984

The SS concentrations of the upper layers decrease from 140 mg/k (at the

turbulence point) to 26 mg/i (at the curtains). The concentrations of the

bottom layers change from 1,100 mg/k to 29 mg/i.

Figure 19 shows the data on May 21, 1984. The SS concentrations change

more gently than on February 3. This may be due to the differences in parti- .,.

cle size and tide velocity.

Distance froM the Curtain

170m 100 5o 20 0o 1P 3O

Curta i i' "

.2

Figure 

19. 

Change 

in SS concentrations 

inside 

curtains, 

May 21, 1984.

99

**A~ **~' -N.--.....P..-..-.

'. p . .. *',**.%-. . . . . . .
Figure 20 shows the horizontal change in SS concentrations at the upper

and lower layers. These figures suggest that the influence of the curtains

begins to act about 100 m from the curtains.

mg/; Distance from Curtain (m)

160 140 120 100 80 60 40 20 0

140 - " 

120 Curtain

100.

80- La 0

60 Feb. 3

40-

May 21

0'

a. Upper layers

Distance from Curtain (m)

160 140 120 100 80 60 40 20 0

mg/Z % -

~ 1200

- Curtain .- 1000-

'J May 21 . 0 800 :>

600

400

200

S0

b. Lower layers

Figure 20. Horizontal change in SS concentrations

277

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CHANGE IN SS CONCENTRATIONS OUTSIDE CURTAINS

The tide flows are changed by the curtains but return to normal after

passing through the bottom openings.

Themu minimu Point

downarddirconcTeratone of ath4gis obhesprtain at aote 20ndro

theid cutis. lopromd Atrtepitofmnmmcnetrtotefo

f~ h ~ ~ low ~ ~~Ve iue2 pward hw hspeoeo Un Flwowl.Th e

suspnsin rsuls i inreaed SMinimumraCon. Poit apit10mfo h

Atrthens passcatig1 direty undert the eutainsde folows veiliy in-urn

Sdownwo ackrudicin Theresf Soenattis pin the spn epaino. aen

soldsis paoperformed.tAfte the pavoin of minm concentration udate flow

turnsit upwr.ns Atlre tmhesoldimpartie that are rsuspendedly themojet

fy low andrtens upAdflow.iFiur 21rtshowshisl phenompe clery The vre-u

surpspeso raesultsificasedn SSloncenitreination tao 100mpfrom theyN

This peapefr hatued thten beavio ofttSSngconce nratinsaondani

tubiit crtin. e eane tatseimnttin s ubtatill2pomte

S~o%

by te crtans.Antituridiy crtans soul beappied fte fo vaiou

purposes ofwtrcaiiainaogwtsdmnain oxmlte
mg/z Distance from Curtain

0 20 40 60 80 100 m

20

16 -'-Curtain

16 --

14 -

o12

a' 10 M(0

00

2

0

Figure 21. Change in SS concentrations outside the curtains

279*B

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