Water-Resources Investigations Report 90-4181 

CHARACTERIZATION OF BOTTOM-SEDIMENT, WATER, 

AND ELUTRIATE CHEMISTRY AT SELECTED STATIONS 

AT REELFOOT LAKE, TENNESSEE 

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Prepared by the 

U.S. GEOLOGICAL SURVEY 

in cooperation with the 

U.S. FISH AND WILDLIFE SERVICE ; 
CHARACTERIZATION OF BOTTOM-SEDIMENT, WATER, 

AND ELUTRIATE CHEMISTRY AT SELECTED STATIONS 

AT REELFOOT LAKE, TENNESSEE 

By Robert E. Broshears 

U.S. GEOLOGICAL SURVEY 

Water-Resources Investigations Report 90-4181 

Prepared in cooperation with the 

U.S. FISH AND WILDLIFE SERVICE 

Nashville, Tennessee 

1991 
U.S. DEPARTMENT OF THE INTERIOR 

MANUEL LU JAN, JR., Secretary * 

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director 

For additional information write to: Copies of this report can be purchased from: 

District Chief 

U.S. Geological Survey 

810 Broadway, Suite 500 

Nashville, TN 37203 

U.S. Geological Survey 

Books and Open-File Reports Section 

Federal Center, Building 810 

Box 25425 

Denver, CO 80225 
CONTENTS 

Abstract 1 

Introduction 1 

Purpose and scope 3 

Description of the study area 3 

Sample collection and processing 4 

Bottom-sediment chemistry 5 

Water chemistry 8 

Elutriate chemistry 8 

Summary 12 

References cited 13 

ILLUSTRATION 

Figure 1. Map showing location of sampling stations at Reelfoot Lake 2 

TABLES 

Table 1. Concentrations of solid-phase inorganic constituents in discrete 

vertical increments of sediment cores collected at Reelfoot Lake, 

November 1988 5 

2. Concentrations of major and minor inorganic constituents and properties 

of water collected at Reelfoot Lake, November 1988 9 

3. Concentrations of selected inorganic constituents and properties of 

unfiltered elutriate water produced by mixing bottom sediments 

and lake water from Reelfoot Lake, November 1988 10 

4. Percent mortality of Ceriodaphnia dubia following exposure to 25-percent 

dilutions of unfiltered elutriate water produced by mixing bottom sediments 

and lake water from Reelfoot Lake, November 1988 12 

. . . 

111 
CONVERSION FACTORS AND VERTICAL DATUM 

For those readers who may prefer to use metric units rather than the inch-pound units 

used in this report, conversion factors are listed below: 

Multiply BY To obtain 

inch (in.) 

foot (ft) 

pound (lb) 

gallon (gal) 

25.4 millimeter 

0.3048 meter 

0.4536 kilogram 

3.785 liter 

Sea level: In this report “sea level” refers to the National Geodetic Vertical Datum of 

1929 (NGVD of 1929) - a geodetic datum derived from a general adjustment of the 

first-order level nets of both the United States and Canada, formerly called Sea Level 

Datum of 1929. 

Use of the brand names in this report is for identification purposes only and does not 

constitute endorsement by the U.S. Geological Survey. 
CHARACTERIZATION OF BOTTOM-SEDIMENT, WATER, 

AND ELUTRIATE CHEMISTRY AT SELECTED STATIONS 

AT REELFOOT LAKE, TENNESSEE 

by Robert E. Broshears 

ABSTRACT 

To better-understand andpredict thepotential 

efSect of dredging on water quality at Reelfoot Lake, 

chemical analyses were conducted on samples of 

lake water, bottom sediment, and elutriate water. 

Chemical analyses were conducted on samples of 

lake water, bottom sediment, and elutriate water 

collected at five stations in the lake during November 1988. Lake water was of the calcium magnesium bicarbonate type with an average 

dissolved-solids concentration of 120 milligrams 

per liter. Trace constituents werepresent in bottom 

sediments at concentrations representative of their 

average relative abundance in the earth’s crust. 

Elutriate waters prepared by mixing bottom sediment and lake water had suspended-solids concentrations as high as 2,000 milligrams per liter 

which exerted significant oxygen demand Trace 

constituents in the unfiltered elutriate waters were 

elevated with respect to lake water; elevated concentrations were attributable to the increased 

suspended-solids concentrations. Concentrations 

of total-recoverable copper, lead., and zinc in many 

elutriate waters exceeded U.S. Environmental 

Protection Agency’s water-quality criteria for the 

protection offreshwater aquatic life. The toxicity of 

elutriate waters, as measured by a 48-hour bioassay 

with Ceriodaphnia dubia, was low. 

INTRODUCTION 

Reelfoot Lake in northwestern Tennessee 

(fig. 1) is a valuable resource that is threatened by 

natural processes and man’s activity. The natural 

aging of the lake has been accelerated by erosion 

of adjacent uplands, nutrient and sediment runoff 

from local agricultural areas, and waste-water discharge from lake-side communities (Tennessee 

Wildlife Resources Agency, 1985). During the 

past several decades, these processes have caused 

deterioration in the quality of the lake’s sport fish 

and waterfowl habitat. In response, State and 

Federal agencies are seeking new management 

strategies for the lake. 

Decisions concerning management options 

for Reelfoot Lake will be guided by an understanding of the physical, chemical, and biological 

processes that determine water quality. The U.S. 

Fish and Wildlife Service is contemplating a program of in-lake channelization that would involve 

dredging as much as 5 feet of lake bottom 

material. The effects of dredging on aquatic life 

in the lake will be influenced by many site-specific 

factors, including the extent, timing, and 

mechanisms of dredging and species-specific 

habitat needs and ability to survive short-term 

stresses. 

1 
Figure 1 .--Sampling stations at Reelfoot Lake .
The Tennessee Department of Health and 

Environment has reported concentrations of 

nutrients and several toxic trace metals in lake 

water that exceed U.S. Environmental Protection 

Agency’s water-quality criteria (Denton, 1987). 

Trace elements characteristically are associated 

with sediments, and their solubility may be enhanced in the anaerobic environment of buried 

bottom materials. Sediments may also be enriched in nitrogen and phosphorus species 

derived from decaying vegetation. Accordingly, 

dredging of the lake bottom could increase concentrations of these critical constituents in the 

water column, with a corresponding degradation 

in water quality. 

Purpose and Scope 

In 1988, the U.S. Geological Survey 

(USGS) entered into a cooperative agreement 

with the U.S. Fish and Wildlife Service (USFWS) 

to conduct a preliminary characterization of 

bottom sediment and water chemistry at Reelfoot 

Lake. The purpose of this report is to describe 

sample collection and processing during the investigation and to present the results of chemical 

analyses of bottom sediment and water. The 

scope of the investigation was limited to the collection of samples in November 1988 from five 

stations and the analysis of selected inorganic 

constituents in sediment cores, column water, and 

elutriate water. Elutriate water was produced by 

mixing bottom sediments and lake water. A 

bioassay was performed for the elutriate water 

only. 

Description of the Study Area 

Reelfoot Lake was formed after the 

earthquakes of 1812 (New Madrid) that shook 

northwestern Tennessee. Variable uplift and 

subsidence altered local drainage patterns and 

contributed to the formation of the lake (fig. l), 

which today covers about 15,500 acres (Robbins, 

1985). Highly erodible loess bluffs parallel the 

lake’s eastern shoreline; the Mississippi River lies 

approximately 3 miles to the west. The lake 

provides abundant habitat for wildlife, including 

bald eagles, mallards, Canada geese, wood ducks, 

and white-tailed deer. It also supports recreational and commercial fishing. Popular catches 

include bass, crappie, bluegill, and catfish. 

The early hydrology of Reelfoot Lake was 

dominated by natural cycles of flood and drought. 

Water levels rose in concert with those in the 

Mississippi River. Silt deposition alternated with 

scouring before a levee completed in 1920 effectively isolated the lake from the river. Since 193 1, 

a spillway at the southern end of the lake has 

maintained a pool elevation near 282.2 feet above 

sea level. 

Agriculture and lake-side development 

have increased sediment and nutrient loading to 

the lake, thereby accelerating its natural aging. 

This loading, combined with the maintenance of 

a static pool elevation, has led to the development 

of a layer of unconsolidated muck on the lake 

bottom which is several feet thick in many areas 

of the lake. 

A potential lake-management strategy calls 

for lowering the pool elevation to promote consolidation of the muck (Hoos and others, 1988). 

The plan requires the deepening of channels to 

facilitate drainage along strategic flow paths. 

Concern exists that dredging these channels may 

lead to the release of toxic constituents from the 

dredged material. 

The lake has been the subject of several 

investigations by State and Federal agencies and 

was classified by the U.S. Environmental Protection Agency (1976) as being “highly eutrophic.” A 

study by the Tennessee Department of Public 

Health (1982) identified the effects of nonpoint 

sources of pollution on lake quality, including the 

effects of sediment loading resulting from agriculture and stream channelization (Denton, 1986). 

3 
Nutrient loading to the lake was estimated at were analyzed for major and minor inorganic con64,370 kilograms per year (kg@) of total phos- stituents and nutrient species by the USGS waterphorus and 334,760 kg&r of total nitrogen (FIN quality laboratory. Field measurements of disAssociates, 1987). Historically, point sources of solved oxygen, specific conductance, pH, and 

pollutants in the basin include septic tanks and water temperature were made. 

feedlots (U.S. Environmental Protection Agency 

(1976). Measurements of sediment oxygen Three sediment cores were collected at 

demand range from 0.057 to 0.267 grams of each sampling station with a Wildco hand corer. 

oxygen per square meter per hour (Hoke S. This sampling device consists of a stainless-steel 

Howard, U.S. Environmental Protection Agency, barrel equipped with a liner tube made of celwritten commun., 1989). Concentrations of cad- lulose acetate butyrate. The liner tube is 2 inches 

mium, chromium, copper, lead, mercury, nickel, in diameter. The core barrel was inserted 

and zinc in the lake or its tributaries have ex- manually into the lake bottom material and then 

ceeded Federal and State water-quality criteria slowly withdrawn. During withdrawal, the sedi- 

(Denton, 1987). ment core was held in place within the liner tube 

by an eggshell core catcher fixed to the lower end 

Storm-event sampling of the major of the tube and a flutter valve at the upper end of 

tributaries to Reelfoot Lake indicates that most the steel barrel. The liner tube was removed from 

nutrient and sediment loading is associated with the sampler, and water overlying the sediment 

high-flow events (Jerry Garrett, U.S. Geological core was slowly drained. Lengths of recovered 

Survey, written commun., 1989). From October core sample varied because of differences in the 

1987 through September 1989, samples were col- texture of the bottom material and in the degree 

lected at North Reelfoot Creek, South Reelfoot of compaction after core removal. Cores were 

Creek, and Running Slough. During this period, maintained in a vertical position during transport 

about 98 percent of the annual suspended- to a lakeside laboratory, where they were immesediment load of 373,000 tons was transported by diately frozen. 

storm events. The mean-annual load of total 

nitrogen during the period was 227,000 kg; the Two frozen cores from each station were 

mean annual load of total phosphorus was sectioned into vertical increments of 10 to 

59,000 kg. 14 inches. One set of vertical increments from 

each station was analyzed by the USGS soils 

laboratory for solid-phase concentrations of 

selected inorganic constituents. A second set of 

SAMPLE COLLECTION AND PROCESSING vertical increments was used for elutriate tests. 

The third frozen core from each station was 

In October 1988, five sampling locations reserved for the analysis of organic constituents 

were selected by the USFWS and the USGS by the USFWS at a later date. 

(fig. 1). Each of these stations represents an area 

where relatively shallow water overlies mucky Elutriate tests were performed at Memphis 

bottom material. Samples of lake water and State University within 72 hours of sample collecbottom-sediment cores were collected at each of tion. Water samples were chilled prior to the 

these stations in November 1988. tests; bottom-material samples were permitted to 

thaw before the tests began. The wet weight of 

Lake water was collected by lowering a the sediment-core increment was determined. 

weighted, vertically mounted, uncapped glass bot- This sediment and a weight of unfiltered lake 

tle through the water column. Water samples water equal to four times the sediment wet weight 

4 
were placed in a 4-liter Erlenmeyer flask. Sediment and water were mixed for 30 minutes at

room temperature on an orbital shaker at approximately 100 revolutions per minute. After

the mixture was allowed to settle for 60 minutes,

the elutriate water was siph3ned from the flask.

Unfiltered elutriate water was analyzed by the

USGS for selected inorganic constituents.

The elutriate water was also used for a

bioassay. Ceriodaphnia dubia, a cladoceran crustacean, were exposed individually to 25-percent

dilutions of the elutriate water. Mortality in

10 replicate bioassays was recorded after

48 hours.

Table 1. -Concentrations ofsolidphase inorganic constituents in discrete vertical

increments ofsediment cores collected at Reelfoot Lake, November 1988

BOTTOM-SEDIMENT CHEMISTRY

Concentrations of solid-phase inorganic

constituents varied little among stations (table 1).

Also, at each station, constituent concentrations

showed little variability with depth of the sediment core. Individual elements were not present

in concentrations that would indicate unnatural

sources of contamination. Concentrations of

each element generally were representative of

their relative abundance in the earth's crust

(Mason, 1958; Hem, 1985).
Table 1 . -Concentrations ofsolidphase inorganic constituents in discrete vertical

increments ofsediment cores collected at Reelfoot Lake, November 1988 -Continued
Table 1 . -Concentrations ofsolidphase inorganic constituents in discrete vertical

increments ofsediment cores collected at Reelfoot Lake, November 1988 - Continued
WATER CHEMISTRY The physical and chemical properties of the 

Concentrations of major and minor inorganic constituents and properties of lake water 

were relatively consistent among stations 

(table 2). Water was of the calcium magnesium 

bicarbonate type and was moderately hard. Concentrations of dissolved solids averaged about 

120 milligrams per liter (mg/L). Comparisons of 

concentrations of trace metals in filtered 

(0.45micrometer filter) and unfiltered samples 

revealed that a sizable fraction of these constituents are associated with particulate matter. 

Primary water-quality standards established by 

the State of Tennessee (Tennessee Department 

of Health and Environment, 1988) were not exceeded in any of the samples. For the unfiltered 

samples, the secondary water-quality standard for 

iron [300 micrograms per liter (@I)] was exceeded at 4 of 5 sites and manganese exceeded the 

secondary standard (50,~@L) at all stations. Concentrations of nitrogen and phosphorus species 

generally were low. Most nitrogen was present in 

association with organic material. 

ELUTRIATE CHEMISTRY 

Elutriate tests provide an index of short- Concentrations of several total-recoverable 

term chemical degradation that may occur when trace elements in the elutriate waters exceeded 

bottom material is mixed with overlying water water-quality criteria for freshwater with a hardduring dredging or other channelization activity. ness of 100 mg/L as calcium carbonate (U.S. EnBecause the mechanics of mixing in a field situa- vironmental Protection Agency, 1986). For the 

tion will vary with site-specific conditions and the protection of freshwater aquatic life, the l-hour 

types of equipment used, concentrations of con- average concentration of total recoverable copstituents measured in elutriate tests may differ per should not exceed 18 &L more than once 

from concentrations that will occur during an ac- every 3 years (U.S. Environmental Protection 

tual dredging operation. Also, elutriate tests do Agency, 1986). This recommended concentranot determine the longer term chemical behavior tion of copper was exceeded in all elutriate 

or biological effects of the constituents that are samples. Similarly, the l-hour average conmeasured. Accordingly, the results of this study centration of total-recoverable lead should not 

represent only a preliminary indication of conditions that may result from dredging at Reelfoot 

exceed 82&L more than once every 3 years (U.S. 

Environmental Protection Agency, 1986). This 

Lake. concentration of lead was exceeded in 4 of the 

unfilteredklutriate waters contrasted sharplywith 

those of lake water (table 3). Perhaps the most 

striking observation was the decline in the concentration of dissolved oxygen, which decreased 

by as much as 8.0 mg/L. For each station, bottom 

material derived from deeper sections of the core 

exerted a higher oxygen demand than did the 

uppermost vertical increment. This oxygen 

demand can be attributed to the oxidation of sulfides and reduced species of iron and manganese. 

Values of pH also dropped during all elutriate 

tests. This change may be attributable to the 

release of organic acids from bottom material, or 

the evolution of hydrogen ions during the oxidation of sulfides. 

Unfiltered elutriate waters had suspendedsediment concentrations of approximately 

2,000 mg/L (Stephen J. Klaine, Memphis State 

University, written commun., 1989). Concentrations of trace elements in elutriate waters 

reflected the high levels of suspended material 

(table 3). Aluminum and iron - principal constituents of the minerals that compose local silts 

and clays - were dominant. Concentrations of 

most trace elements occurred in approximately 

the same ratios as their concentrations in the bulk 

bottom material. 

8 
Table 2. - Concentrations ofmajor and minor inorganic constituents and

properties ofwater collected at Reelfoot Lake, November 1988
Table 3. -Concentrations ofselected inorganic constituents andproperties ofunfiltered elutriate water

produced by mixing bottom sediments and lake waterfrom Reelfoot Lake, November 1988
Table 3. - Concentrations ofselected inorganic constituents andproperties ofunfiltered

elutriate waterproduced by mixing bottom sediments and lake waterfrom Reelfoot

Lake, November 1988 -Continued
13 elutriate samples. The concentration of totalrecoverable zinc should not exceed 117,ug/L at

any time (U.S Environmental Protection Agency,

written commun., 1989). This concentration of

zinc was exceeded in 12 of the 13 elutriate

samples.

Although concentrations of trace elements

in the unfiltered elutriate water exceeded some

water-quality criteria, their bio-availability may

be limited because they are associated with particulate matter. Limited bio-availability may be

one reason why very little toxicity was

demonstrated in the 48-hour bioassays with

Ceriodaphnia dubia. In half of the bioassays, no

mortality was observed (table 4). Mortality exceeded 10 percent only in the diluted elutriate

water prepared from the shallowest bottom sediments collected near Samburg (fig. 1, station 2).

Table 4. -Percent mortality ofCeriodaphnia

dubiafollowing exposure to 25percent dilutions ofunfiltered elutriate waterproduced by

mixing bottom sediments and lake waterfrom

Reelfoot Lake, November 1988

SUMMARY

To better understand and predict the potential effect ofdredging on water quality at Reelfoot

Lake, chemical analyses were conducted on

samples of lake water, bottom sediment, and

elutriate water. Samples of water and sediments

were collected during November 1988 at five stations in the lake and analyzed for inorganic constituents including nutrients and trace metals.

Additionally, elutriate samples obtained by

mixing native lake water with sediment samples

were analyzed for selected trace elements and

oxygen demand.

The results ofthe investigation showed that:

1. Concentrations of inorganic constituents

in the water and sediments did not vary

significantly among the five sampling

sites . There were no significant changes

in the concentration of inorganic constituents with depth of the cored sediments.

2. The concentrations of trace elements in

the sediments were typical of values in

surface soils, with no toxic concentrations detected.

3. The principal ions in the water were calcium, magnesium, and bicarbonate.

Dissolved-solids concentrations

averaged 120 mg/L.

4. Trace elements and nutrients in the

water were associated with particulate

matter, and did not occur at concentrations exceeding water-quality criteria for

the protection of aquatic life .

5. Elutriate samples from the mixing oflake

water and sediments exerted oxygen

demands as high as 8 mg/L. Deeper sections of cored sediment samples
exhibited higher oxygen demands than 

shallower sections of the sediment cores. 

6. Maximum recommended concentrations 

for the protection of aquatic life for copper, lead, and zinc were exceeded in 

several of the elutriate samples. However, 48-hour toxicity tests of the elutriate with Ceriodaphnia dubia resulted in 

mortality rates less than 10 percent. 

REFERENCES CITED 

Denton, G.M., 1986, Summary of sedimentation studies of 

Reelfoot Lake, 1982-1986: Nashville, Tennessee, 

----- 1987, Water quality at Reelfoot Lake, 1976-1986: NashTennessee Department of Health and Environment, 

ville, Tennessee, Tennessee Department of Health 

Office of Water Management, 35 p. 

and Environment, Off& of Water Management, 81 p. 

FIN Associates, 1987, Water quality analysis task series 300 

report, Reelfoot Lake, Tennessee: Little Rock, 

Arkansas, FIN Associates, prepared for U.S. Environmental Protection Agency Region IV, Atlanta, 

55 p. 

Hem, J.D., 1985, Study and interpretation of the chemical 

characteristics of natural water (3rd ed.): U.S. 

Geological Survey Water-Supply Paper 2254,263 p. 

Hoes, A.B., Tucci, Patrick, Bryan, B.A., and Carey, W.P., 

1988, Hydrology of the Reelfoot Lake basin, Obion 

and Lake Counties, Tennessee, May 1984 to May 

1987, and potential effects on proposed lake-level 

manipulation, in Final Environmental Impact Statement, Reelfoot Lake Water Level Management, 

Obion and Lake Counties, Tennessee, and Fulton 

County, Kentucky: Atlanta, Georgia, U.S. Fiih and 

Wildlife Service, Southeast Region, appendix D, 

p. l-74. 

Mason, Brian, 1958, Principles of geochemistry (26 ed.): 

New York, John Wiley and Sons, 310 p. 

Robbii, C.H., 1985, Hydrology of the Reelfoot Lake basin, 

Obion and Lake Counties, northwestern Tennessee: 

Tennessee Department of Health and Environment, 1988, 

U.S. Geological Survey Water-Resources InvestigaPublic water systems, in Rules of Tennessee Department of Health and Environment, Bureau of Environtions Report 85-4097,29 p. 

ment, Division of Water Supply: Tennessee 

Department of Health and Environment, Chapter 

12OO-5-1,61 p. 

Tennessee Department of Public Health, 1982, Reelfoot 

Lake report, a summary report prepared for the Reelfoot Lake rural clean water program project in Tennessee: Nashville, Tennessee, Tennessee Department of Public Health, Division of Water Pollution 

Control 157 p. 

Tennessee Wildlife Resources Agency, 1985, Reelfoot Lake 

- an assessment for water-level management: Jackson, Tennessee, Tennessee Wildlife Resources 

Agency, Region I, 65 p. 

U.S. Environmental Protection Agency, 1976, Report on 

Reelfoot Lake, Obion County, Tennessee: The Environmental Protection Agency National Eutrophication Survey, 80 p. 

--- 1986, Quality criteria for water 1986: U.S. Environmental Protection Agency, Office of Water Regulations 

and Standards, EPA 440/5-86-001,457 p. 

13