U.S. Department of the Interior

U.S. Geological Survey

Open-File Report 2010–1050

Review of Oceanographic and Geochemical Data Collected 

in Massachusetts Bay during a Large Discharge of Total 

Suspended Solids from Boston’s Sewage-Treatment System 

and Ocean Outfall in August 2002
Cover. Deployment of a subsurface mooring in Massachusetts Bay from the U.S. Coast Guard Cutter Marcus Hanna. The yellow 

funnel-shaped instrument below the red subsurface float is the time-series sediment trap used to collect data shown in figures 3–9.
Review of Oceanographic and Geochemical 

Data Collected in Massachusetts 

Bay during a Large Discharge of Total 

Suspended Solids from Boston’s SewageTreatment System and Ocean Outfall in 

August 2002

By Michael H. Bothner, Bradford Butman, and Michael A. Casso

Open-File Report 2010–1050

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2010

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Suggested citation:

Bothner, M.H., Butman, Bradford, and Casso, M.A., 2010, Review of oceanographic and geochemical data 

collected in Massachusetts Bay during a large discharge of total suspended solids from Boston’s sewagetreatment system and ocean outfall in August 2002: U.S. Geological Survey Open-File Report 2010–1050, 11 p., 

at http://pubs.usgs.gov/of/2010/1050/.
iii

Contents

Abstract...........................................................................................................................................................1

Introduction.....................................................................................................................................................1

Oceanographic and Geochemical Data.....................................................................................................1

Bottom Photographs ............................................................................................................................3

Near-Bottom Time-Series Observations...........................................................................................4

Sediment Traps......................................................................................................................................5

Sediment-Trap Sample Analysis ........................................................................................................7

Surficial Sediments...............................................................................................................................7

Summary..........................................................................................................................................................7

References Cited..........................................................................................................................................11

Figures

1. Map showing location of the Massachusetts Bay outfall, U.S. Geological Survey 

long-term mooring station A (LT-A), and sediment sampling station 3................................2

2. Photographs of the sea floor from an instrumented tripod on (A) August 10, 2002, 

1840 GMT; and (B) August 25, 2002, 1704 GMT ........................................................................3

3. Graphs showing (A) significant wave height at National Oceanic and Atmospheric

Administration buoy 44013; (B) standard deviation of burst pressure; (C) beam

attenuation; (D) sediment-trapping rate at 10-day intervals from time-series

sediment trap; and (E) current speed at a depth of 31 meters, 2002....................................4

4. Graphs showing (A) significant wave height at National Oceanic and Atmospheric

Administration buoy 44013; (B) standard deviation of burst pressure; (C)

sediment-trapping rate from time-series sediment trap at 4 meters above bottom

and total suspended solids concentration from the Deer Island Sewage Treatment

Plant; (D) beam attenuation; (E) current speed at a depth of 31 meters at station

LT-A for August–September 2002...............................................................................................5

5. Graphs showing total suspended solids concentrations from Massachusetts Water

Resources Authority records and sediment-collection rate in a time-series

sediment trap deployed at station LT-A during (A) summer 2002, (B) summer 2003,

and (C) summer 2004 ....................................................................................................................6

6. Graph showing concentration of Clostridium perfringens in sediment-trap samples

at the end of each 10-day sampling interval and concentration of total suspended

solids in the waste steam at the Deer Island Sewage Treatment Plant on the day of

collection, summer 2002 ..............................................................................................................8

7. Graph showing concentrations of silver and copper in sediment-trap samples at

the end of each 10-day sampling interval and concentration of total suspended

solids in the waste steam at the Deer Island Sewage Treatment Plant on the day of

collection, summer 2002 ..............................................................................................................8
iv

Conversion Factors

Multiply By To obtain

Length

centimeter (cm) 0.3937 inch (in.)

millimeter (mm) 0.03937 inch (in.)

meter (m) 3.281 foot (ft) 

kilometer (km) 0.6214 mile (mi)

kilometer (km) 0.5400 mile, nautical (nmi) 

meter (m) 1.094 yard (yd) 

Area

square kilometer (km2

) 247.1 acre

square centimeter (cm2

) 0.001076 square foot (ft2)

square meter (m2

) 10.76 square foot (ft2) 

Volume

liter (L) 0.2642 gallon (gal)

cubic meter (m3

) 0.0002642 million gallons (Mgal) 

cubic centimeter (cm3

) 0.06102 cubic inch (in3) 

Mass

gram (g) 0.03527 ounce, avoirdupois (oz)

Density

gram per cubic centimeter (g/cm3

) 62.4220 pound per cubic foot (lb/ft3) 

Pressure

millibar (mb) 0.0145038 pounds per square inch (lb/in2

)

Concentrations of chemical constituents in water are given in milligrams per liter (mg/L). 

Concentrations of chemical constituents on dried sediment are given in parts per million (ppm), 

which are equivalent to micrograms of constituent per gram of dry sediment.

8. Graph showing concentrations of organic carbon, iron, and arsenic in

sediment-trap samples at the end of each 10-day sampling interval and

concentration of total suspended solids in the waste steam at the Deer Island

Sewage Treatment Plant on the day of collection, summer 2002.........................................9

9. Graph showing concentrations of cadmium, mercury, lead, and zinc in

sediment-trap samples at the end of each 10-day sampling interval and

concentration of total suspended solids in the waste steam at the Deer Island

Sewage Treatment Plant on the day of collection, summer 2002.........................................9

10. Graphs showing concentrations of (A) silver, (B) Clostridium perfringens, 

and (C) clay in surface sediments at station 3, 1989–2007...................................................10
Review of Oceanographic and Geochemical Data 

Collected in Massachusetts Bay during a Large Discharge 

of Total Suspended Solids from Boston’s SewageTreatment System and Ocean Outfall in August 2002

By Michael H. Bothner, Bradford Butman, and Michael A. Casso

Abstract

During the period August 14–23, 2002, the discharge of 

total suspended solids (TSS) from the Massachusetts Water 

Resources Authority sewage-treatment plant ranged from 32 to 

132 milligrams per liter, causing the monthly average discharge to exceed the limit specified in the National Pollution 

Discharge Elimination System permit. Time-series monitoring 

data collected by the U.S. Geological Survey in western Massachusetts Bay were examined to evaluate changes in environmental conditions during and after this exceedance event. The 

rate of sediment trapping and the concentrations of near-bottom suspended sediment measured near the outfall in western 

Massachusetts Bay increased during this period. Because 

similar increases in sediment-trapping rate were observed 

in the summers of 2003 and 2004, however, the increase in 

2002 cannot be definitively attributed to the increased TSS 

discharge. Concentrations of copper and silver in trapped 

sediment collected 10 and 20 days following the 2002 TSS 

event were elevated compared to those in pre-event samples. 

Maximum concentrations were less than 50 percent of toxicity 

guidelines. Photographs of surficial bottom sediments obtained 

before and after the TSS event do not show sediment accumulation on the sea floor. Concentrations of silver, Clostridium 

perfringens, and clay in surficial bottom sediments sampled 

10 weeks after the discharge event at a depositional site 3 

kilometers west of the outfall were unchanged from those 

in samples obtained before the event. Simulation of the TSS 

event by using a coupled hydrodynamic-wave-sediment-transport model could enhance understanding of these observations and of the effects of the exceedance on the local marine 

environment.

Introduction

From August 14 to 23, 2002, the discharge of total 

suspended solids (TSS) from the Deer Island Sewage Treatment Plant (DITP) through the Massachusetts Bay outfall 

exceeded the 30-mg/L limit (monthly average) specified in the 

National Pollution Discharge Elimination System (NPDES) 

permit granted by the U.S. Environmental Protection Agency. 

The event was caused by an upset in the secondary treatment 

process caused by “an overgrowth of filamentous bacteria” 

related to “discharge of sulfate-rich industrial effluent to the 

DITP through the Massachusetts Water Resources Authority 

(MWRA) Alford Street Pump station” (Michael Hornbrook, 

Massachusetts Water Resources Authority, written commun., 

2002). The peak TSS concentration during the exceedance 

event was 132 mg/L on August 18, 2002. This report examines 

observations made by the U.S. Geological Survey (USGS) in 

Massachusetts Bay to document the effects of the exceedance 

event in the water column and on the sea floor.

Oceanographic and Geochemical Data

The USGS has carried out a long-term research program 

(1989–2006) to investigate the transport and fate of sediments 

in Massachusetts Bay (Bothner and Butman, 2007). As part 

of this program, time-series oceanographic observations and 

geochemical analyses of suspended and bottom sediments 

were made at locations near the Massachusetts Bay outfall 

(fig. 1). Measurements relevant to the August 2002 exceedance event include (1) sequential photographs of the sea floor; 

(2) observations of near-bottom light attenuation, pressure, 

and current speed; (3) sediment-trapping rates; (4) chemical 

analyses of trapped sediment; and (5) chemical analyses of 

surficial bottom sediment.

To provide a context for this review, we made an orderof-magnitude estimate of the concentration of suspended solids in the water column and the maximum amount that might 

accumulate on the sea floor at the site of the USGS time-series 

observations following the exceedance event. We used the 

dilution model results presented by Signell (2007) that predict 

that, on average, the concentration of effluent in the water 1.5 

km from the outfall would be diluted to about 1 percent of the 

initial concentration. Concentrations would be higher nearer 

to the outfall and lower farther from the outfall. The TSS 
2 Data Collected in Massachusetts Bay during a Large Discharge of Total Suspended Solids in August 2002

71° 70°50'

42°20'

42°30'

Water depth, in meters

0 40

0

0

6 KILOMETERS

5 MILES

Boston

Harbor

LT-A

Station 3

Massachusetts

Bay outfall

Figure 1. Location of the Massachusetts Bay outfall, U.S. Geological Survey long-term mooring station A (LT-A), and sediment 

sampling station 3.
Oceanographic and Geochemical Data 3

concentration in effluent diluted to 1 percent would be about 

0.7 mg/L and would be confined to the lower 15 m of the 

water column by the summer thermocline. If all of this material settled on the sea floor during the 10-day TSS event and 

remained there, the deposition near the USGS moorings would 

be a layer about 0.6 mm thick (if a wet bulk density of 1.2 g 

wet/cm3 is assumed). This estimate is an upper limit because 

the effluent would be increasingly diluted farther from the outfall and because the dilution calculations are for a conservative 

tracer (that is, no settling). The estimate could be improved 

by running a coupled hydrodynamic-wave-sediment-transport 

model for the time period of the TSS event with a modification 

that allows TSS particles to sink at measured sinking rates. 

This approach would provide estimates of sediment concentration and accumulation throughout Massachusetts Bay associated with this event.

Bottom Photographs

Photographs of the sea floor were taken every 4 hours 

from a camera fixed about 2 m above the bottom at station 

LT-A (fig. 1) about 1.3 km south of the outfall site at a water 

depth of about 32 m (Butman and others, 2008). A comparison 

of photographs taken before and after the event (fig. 2) shows 

no obvious accumulation of fine sediment on the gravelly 

B

A

0

0

10 CENTIMETERS

5 INCHES

0

0

10 CENTIMETERS

5 INCHES

Figure 2. Photographs 

of the sea floor from an 

instrumented tripod (U.S. 

Geological Survey mooring 

number 690) on (A) August 

10, 2002, 1840 GMT; and (B) 

August 25, 2002, 1704 GMT. 

The original photographs 

were tinged red and 

underexposed, especially in 

the periphery; the bright spot 

reflects the strobe light that 

illuminated the sea floor. No 

change in sediment cover is 

apparent. (From Butman and 

others, 2008.)
4 Data Collected in Massachusetts Bay during a Large Discharge of Total Suspended Solids in August 2002

bottom or on the compass mounted on the tripod; however, the 

sea floor is poorly illuminated because the instrument was near 

the end of a deployment and the strobe was most likely fouled 

or losing battery power. Even with improved illumination, the 

maximum predicted accumulation of about 0.6 mm would be 

difficult to observe in these photographs.

Near-Bottom Time-Series Observations

The continuous record of beam attenuation (a measure 

of suspended-sediment concentration) at approximately 2 m 

above bottom (in a water depth of about 32 m) shows an 

increase that began on August 18 and reached about 0.5 m-1

on August 23 (figs. 3, 4). There is no calibration of the beam 

transmissometer appropriate for this period, but a 0.5-m-1

increase in beam attenuation is equivalent to about 1 mg/L 

suspended sediment using the calibration in Harris and others (2003) from the middle Atlantic Bight. Beam attenuation 

continued to rise gradually from August 23 to about September 5. From August 18 to about August 23 the currents were 

less than 0.1 m/s and there was no surface wave activity, 

so the increase is unlikely to have been caused by sediment 

resuspension (although a single spike in current speed reached 

0.2 m/s just prior to this event). The increase in beam attenuation could be associated with the TSS event, but also could 

have been caused by advection of different water masses past 

the tripod or occasional resuspension by internal waves that 

occur throughout Massachusetts Bay in summer (Butman 

and others, 2006). The gradual increase in attenuation after 

August 23 is associated with a period of surface waves and 

likely reflects some sediment resuspension from the sea floor. 

Figure 3. (A) Significant wave height at National Oceanic and Atmospheric Administration buoy 44013; (B) standard deviation of burst 

pressure; (C) beam attenuation; (D) sediment-trapping rate at 10-day intervals from time-series sediment trap; and (E) current speed at a 

depth of 31 meters (~1 meter above bottom), 2002. (Trapping rates greater than 20 grams per square meter per day are shown in red; the 

trapping rate, rounded to an integer, is shown at the top of the bar. The period of total suspended solids exceedance is indicated by the 

solid black line in (C). Modified from Butman and others, 2009. See figure 4 for period August 1 to September 15, 2002.)

0

5

10

0

10

20

30

40

50

0

1

2

3

4

5

0

5

10

15

20 30 27 37 32 36

JAN. FEB. MAR. APR. MAY JUNE JULY AUG. SEPT. OCT. NOV. DEC.

0.0

0.1

0.2

0.3

A

B

C

D

E

2002

SPEED,

IN METERS

PER SECOND

SEDIMENT TRAPPING

RATE, IN GRAMS PER

SQUARE METER

PER DAY

BEAM

ATTENUATION,

IN METERS-1

PRESSURE STANDARD

DEVIATION,

IN MILLIBARS

HEIGHT,

IN METERS
Oceanographic and Geochemical Data 5

A gradual increase in background is also typical of biological fouling of the optical windows on the transmissometer; 

the reduction around September 5 is hypothesized to reflect 

removal of material from the transmissometer windows by the 

bottom currents, which increase to more than 0.15 m/s on a 

tidal cycle. The August 18–23 increase in beam attenuation is 

of the same order as the short-term increases observed prior to 

the TSS exceedance event that correlate with small increases 

in wave-induced bottom stress, and is much smaller than the 

peak in attenuation (which exceeded 4 m-1) during the resuspension event on June 16, 2002, associated with surface waves 

(fig. 3). Simulation of the TSS event using a coupled hydrodynamic-wave-sediment-transport model could provide estimates 

of the distribution of suspended sediments associated with the 

TSS event that could be compared to these observations. The 

hydrodynamics have been modeled (for example Signell and 

others, 2000), but the sediment-transport calculations would 

require information on particle-settling velocity of the introduced material, which is presently unavailable.

Sediment Traps

The sediment-collection rate in a time-series sediment 

trap deployed at 4.3 m above bottom at station LT-A (fig. 1) 

increased from about 5 g/m2/d to more than 15 g/m2/d during 

the August 16–25 period (bottle 10 of 13), which is nearly 

synchronous with the discharge event (fig. 5A). Because the 

highest collection rate coincides with a period during which 

little bottom-sediment resuspension was expected (low wave 

heights and bottom current speeds), it would not be unreasonable to consider other sources of settling particulate matter, 

Figure 4. (A) Significant wave height at National Oceanic and Atmospheric Administration buoy 44013; (B) standard deviation of burst 

pressure; (C) sediment-trapping rate from time-series sediment trap at 4 meters above bottom (histogram) and total suspended solids 

(TSS) concentration from the Deer Island Sewage Treatment Plant (dots); (D) beam attenuation; (E) current speed at a depth of 31 

meters (~1 meter above bottom) at station LT-A for August–September 2002. (The period of TSS exceedance (August 14–23) is indicated 

by the heavy black line in (C). Time-series data for station LT-A from Butman and others, 2009; TSS data from Massachusetts Water 

Resources Authority.)

0

5

10

A 

0

10

20

30

B

0

50

100

150

200

0

5

10

15

20

0

1

2

3

4

D

0

0.1

0.2

0.3

E

08/01 08/07 08/13 08/19 08/25 08/31 09/06 09/12

SPEED,

IN METERS

PER SECOND

SEDIMENT TRAPPING

RATE, IN GRAMS PER

SQUARE METER

PER DAY

BEAM

ATTENUATION,

IN METERS-1

PRESSURE STANDARD

DEVIATION,

IN MILLIBARS

HEIGHT,

IN METERS

CONCENTRATION,

IN MILLIGRAMS

PER LITER

2002

C 
6 Data Collected in Massachusetts Bay during a Large Discharge of Total Suspended Solids in August 2002

Figure 5. Total suspended solids (TSS)

concentrations from Massachusetts 

Water Resources Authority records and 

sediment-collection rate in a time-series 

sediment trap deployed at station LT-A 

during (A) summer 2002, (B) summer 

2003, and (C) summer 2004. The dashed 

blue line in (A) shows the start of the 

exceedance event, August 14–23, 

2002. Plots (B) and (C) illustrate that 

increases in sediment-trap collection 

rate can occur in late summer with no 

correspondence to the concentrations 

of TSS leaving the Deer Island Sewage 

Treatment Plant. Higher sedimenttrap collection rates have often been 

observed during periods of low waveinduced bottom stress, and the full 

explanation of the high rates has been 

elusive.

Trap collection rate

Total suspended solids

Exceedance event starts

COLLECTION RATE, IN GRAMS PER SQUARE

METER PER DAY

0.0

2.5

5.0

7.5

10.0

12.5

15.0

17.5

DATE

06/01/02 07/01/02 08/01/02 09/01/02 10/01/02 

COLLECTION RATE, IN GRAMS

PER SQUARE METER PER DAY

0.0

2.5

5.0

7.5

10.0

12.5

15.0

17.5

TOTAL SUSPENDED SOLIDS CONCENTRATION,

IN MILLIGRAMS PER LITER

0

25

50

75

100

125

150

175

DATE

04/01/03 05/01/03 06/01/03 07/01/03 08/01/03 09/01/03 

COLLECTION RATE, IN GRAMS PER SQUARE

METER PER DAY

0.0

2.5

5.0

7.5

10.0

12.5

15.0

17.5

TOTAL SUSPENDED SOLIDS CONCENTRATION,

IN MILLIGRAMS PER LITER

0

25

50

75

100

125

150

175

DATE

06/01/04 07/01/04 08/01/04 09/01/04 

TOTAL SUSPENDED SOLIDS CONCENTRATION,

IN MILLIGRAMS PER LITER

0

25

50

75

100

125

150

175

A

B

C
Summary 7

such as the TSS event, to account for the observed increase. 

However, the high collection rates continued for 30 days 

past the TSS event and increases in trapping rate were also 

observed during August and September of 2003 and 2004, 

which also were periods of low waves and currents (figs. 5B 

and 5C) when TSS discharges were low. We have hypothesized that these recurring late-summer increases in sedimenttrapping rate may be related to decomposition of biological 

mucus that binds sediments, releasing fine sediments into 

the water column even under very low current stress, but this 

hypothesis remains to be fully explored. In addition, the concentration of organic matter in the trap did not increase during 

the high collection rate, which would have been expected from 

the filamentous bacteria that reportedly caused the exceedance event. Because of the recurring seasonal increase in 

sediment-collection rate and the absence of expected chemical signal, the increase in collection rate recorded in bottle 10 

(fig. 5A) cannot be uniquely attributed to the pulse of high 

TSS discharge.

Sediment-Trap Sample Analysis

Analysis of the time-series sediment-trap samples 

revealed that concentrations of Clostridium perfringens

(fig. 6), a chemically resistant bacterium spore found in sewage (Buchholz ten Brink and others, 2000), increased from 

July to mid September and there was no change in this gradual 

increase at the time of the exceedance event. The consistent 

slope of the increase and the observation that the concentration was greatest (50,000 spores/g) about a month after the 

exceedance event make it difficult to conclude that the highest 

Clostridium perfringens concentrations are directly related to 

the event.

The metals copper (Cu) and silver (Ag) (fig. 7), also tracers of sewage particles, reached their maximum concentrations 

(61 and 1.7 ppm, respectively) in a sample obtained 10 days 

(one trapping interval) following the TSS event. These values 

are about 0.5 and 2 times higher, respectively, than the average 

concentrations in pre-event samples (June–mid August). From 

a toxicity perspective, these maximum concentrations are 

below the warning levels set by the NPDES permit for bottom 

sediment (Cu, 270 ppm; Ag, 3.7 ppm). Although the increase 

in the concentrations of these metals is consistent with an 

increase in sewage discharge, running the hydrodynamicwave-sediment-transport model would help to determine 

whether such a delay in the signal reaching the sediment trap 

is reasonable.

There was no difference between the pre- and post-event 

range in concentrations of organic carbon (C), iron (Fe), and 

arsenic (As) (fig. 8), or of cadmium (Cd), mercury (Hg), lead 

(Pb), and zinc (Zn) (fig. 9). There were no chemical analyses of the TSS samples that were collected from the effluent 

stream during the exceedance event. Such data would assist 

in identifying chemical parameters and chemical ratios that 

would link the particles from the treatment plant to those in 

the sediment traps. Would the “overgrowth of filamentous 

bacteria” dilute the signal of Ag and Cu in the TSS, for 

example? Analyses for additional components of a bacteriarich discharge, such as isotopes of sulfur (S), C, and nitrogen 

(N), could be useful as well.

Surficial Sediments

The concentrations of Ag, Clostridium perfringens, and 

clay in a sample of surficial (0–0.5 cm) sediment collected at 

station 3 (fig. 10) about 10 weeks after the TSS exceedance 

event were not appreciably different from those in samples 

collected before the event. This station is about 3 km west of 

the Massachusetts Bay outfall, in a slight depression where 

sediments are muddy. The site is thought to be a sink for fine 

sediments and associated contaminants (Bothner and others, 

2007).

Summary

Oceanographic and geochemical observations in western 

Massachusetts Bay near the MWRA ocean outfall have been 

examined for evidence of the August 2002 high-TSS discharge 

event. The collection rate in a sediment trap at the USGS 

mooring station LT-A, located 1.3 km from the Massachusetts Bay outfall, increased at the same time as the maximum 

TSS discharge and could be directly related; however, such 

increases in trap collection rate also were observed in late 

summer 2003 and 2004 when TSS discharge was low and 

constant, indicating that other natural factors may be responsible for the high collection rates observed in 2002. A small 

increase in concentrations of the typical biochemical tracers 

of sewage particles (Ag, Cu, and Clostridium perfringens) 

was observed in the suspended matter trapped following the 

exceedance event. Chemical analyses of the TSS at the DITP 

during the event are not available and, therefore, direct chemical comparisons between TSS and trapped sediment are not 

presently possible. On the basis of simple calculations and 

a number of assumptions, it is estimated that about 0.6 mm 

of sediment could have been deposited on the sea floor in 

the vicinity of station LT-A in association with the increased 

discharge. Although no accumulation is apparent in the timeseries bottom photographs, an accumulation on the order of 

0.6 mm would be difficult to quantify from these photographs. 

Near-bottom measurements of light attenuation show a small 

increase consistent with increased concentrations of suspended 

sediments between August 14 and August 23. Concentrations of sewage-particle indicators in the surface sediment 

(0–0.5 cm) collected at station 3 about 10 weeks after the TSS 

discharge event were not greater than those in the surface 

sediment collected before the discharge event. Simulation of 

the TSS event using a coupled hydrodynamic-wave-sedimenttransport model may provide additional insight about the fate 

of sewage-derived particulates and facilitate further interpretation of the observations presented here.
8 Data Collected in Massachusetts Bay during a Large Discharge of Total Suspended Solids in August 2002

DATE AT END OF 10-DAY SAMPLING INTERVAL

JUNE JULY AUG. SEPT.

TOTAL SUSPENDED SOLIDS CONCENTRATION,

IN MILLIGRAMS PER LITER

0

50

100

150

0

10,000

20,000

30,000

40,000

50,000

60,000

Total suspended solids

Exceedance event starts

C. perfringens

CLOSTRIDIUM PERFRINGENS CONCENTRATION,

IN CELL-FORMING UNITS PER SALT-FREE DRY GRAM

DATE AT END OF 10-DAY SAMPLING INTERVAL

JUNE JULY AUG. SEPT.

TOTAL SUSPENDED SOLIDS CONCENTRATION,

IN MILLIGRAMS PER LITER

0

50

100

150

COPPER CONCENTRATION, IN PARTS PER MILLION

0

25

50

75

SILVER CONCENTRATION, IN PARTS PER MILLION

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Total suspended solids

Copper

Silver

Exceedance event starts

Figure 6. Concentration of Clostridium perfringens (salt-free) in sediment-trap samples at the end 

of each 10-day sampling interval and concentration of total suspended solids in the waste steam at 

the Deer Island Sewage Treatment Plant on the day of collection, summer 2002.

Figure 7. Concentrations of silver and copper (salt-free) in sediment-trap samples at the end of each 

10-day sampling interval and concentration of total suspended solids in the waste steam at the Deer 

Island Sewage Treatment Plant on the day of collection, summer 2002.
Summary 9

Figure 8. Concentrations of organic carbon, iron, and arsenic (salt-free) in sediment-trap samples at the end of each 10-day sampling 

interval and concentration of total suspended solids in the waste steam at the Deer Island Sewage Treatment Plant on the day of 

collection, summer 2002.

Figure 9. Concentrations of cadmium, mercury, lead, and zinc (salt-free) in sediment-trap samples at the end of each 10-day sampling 

interval and concentration of total suspended solids in the waste steam at the Deer Island Sewage Treatment Plant on the day of 

collection, summer 2002.

DATE AT END OF 10-DAY SAMPLING INTERVAL

JUNE JULY AUG. SEPT.

TOTAL SUSPENDED SOLIDS CONCENTRATION,

IN MILLIGRAMS PER LITER

0

50

100

150

IRON CONCENTRATION, IN PARTS PER MILLION

0

8,000

16,000

24,000

32,000

40,000

48,000

PERCENT ORGANIC CARBON

0

5

10

15

ARSENIC CONCENTRATION, IN PARTS PER MILLION

0

5

10

15

20

25

30

Total suspended

solids

Iron

Organic carbon

Arsenic

Exceedance

event starts

EXPLANATION

DATE AT END OF 10-DAY SAMPLING INTERVAL

JUNE JULY AUG. SEPT.

TOTAL SUSPENDED SOLIDS CONCENTRATION,

IN MILLIGRAMS PER LITER

0

50

100

150

LEAD CONCENTRATION, IN PARTS PER MILLION

0

20

40

60

80

100

ZINC CONCENTRATION, IN PARTS PER MILLION

0

50

100

150

CADMIUM AND MERCURY CONCENTRATION, IN PARTS PER MILLION

0.0

0.2

0.4

0.6

0.8

1.0

Total suspended

solids

Lead

Zinc

Cadmium

Mercury

Exceedance

event starts

EXPLANATION
10 Data Collected in Massachusetts Bay during a Large Discharge of Total Suspended Solids in August 2002

Figure 10. Concentrations of (A) silver (Ag), (B) Clostridium perfringens, and (C) clay in surface sediments (0–0.5 centimeters) at 

station 3, 1989–2007. There is no significant change in the concentrations of Ag, C. perfringens, or clay that could be attributed to the 

total suspended solids (TSS) event in samples of surface sediment that were collected 10 weeks after the August 2002 event. The 

highest Ag concentrations were observed in 1993 and are attributed to the transport of fine-grained sediment bearing Ag from near 

the shore to this location during the intense storm of December 11–16, 1992. Average post-outfall concentrations of Ag at station 

3 are not statistically different from average pre-outfall concentrations (even with storm-related values removed from pre-outfall 

average). The post-outfall concentrations of Ag are not increasing with time. Error bars are defined by analysis of two or more replicate 

samples. Highest concentrations of C. perfringens and clay, like those of Ag, follow the storm of December 11–16, 1992. Average 

post-outfall concentrations of C. perfringens at station 3 are not statistically different from average pre-outfall concentrations (even 

with storm-related values removed from the pre-outfall average). The post-outfall concentrations of C. perfringens are not increasing 

systematically with time. Post-outfall clay content in the 4 years following outfall startup (September 2000) were on average higher and 

more variable than during the 3-year period prior to outfall startup. Variations in the clay content of the surface sediment may account 

for the similar patterns observed in Ag and C. perfringens concentrations during the period. (From Bothner and Butman, 2007, fig. 7.3)

YEAR

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

0

20

40

60

0.0

0.5

1.0

1.5

2.0

0

10,000

20,000

30,000

A

B

C

Storm

Outfall

startup

TSS

event

CONCENTRATION OF CLAY,

 IN PERCENT

CONCENTRATION OF SILVER,

 IN PARTS PER MILLION

CLOSTRIDIUM PERFRINGENS

CONCENTRATION, IN CELL-FORMING

UNITS PER SALT-FREE DRY GRAM
References Cited 11

References Cited

Bothner, M.H., and Butman, B., eds., 2007, Processes influencing the transport and fate of contaminated sediments in 

the coastal ocean–Boston Harbor and Massachusetts Bay: 

U.S. Geological Survey Circular 1302, 89 p. (Also available 

at http://pubs.usgs.gov/circ/2007/1302/.)

Bothner, M.H., Casso, M.A., Rendigs, R.R., Lamothe, P.J., 

and Baldwin, S.M., 2007, Using sediments to monitor 

environmental change in Massachusetts Bay and Boston 

Harbor, in Bothner, M.H., and Butman, Bradford, eds., 

Processes influencing the fate and transport of contaminated sediments in the coastal ocean—Boston Harbor and 

Massachusetts Bay: U.S. Geological Survey Circular 1302, 

section 5, p. 48–55. (Also available at http://pubs.usgs.gov/

circ/2007/1302/.)

Buchholtz ten Brink, M.R., Mecray, E.L., and Galvin, E.L., 

2000, Clostridium perfringens in Long Island Sound sediments—An urban sedimentary record: Journal of Coastal 

Research, v. 16, no. 3, p. 591–612.

Butman, B., Alexander, P.S., Scotti, A., Beardsley, R.C., and 

Anderson, S.P., 2006, Large internal waves in Massachusetts Bay transport sediments offshore: Continental Shelf 

Research, v. 26, no. 17–18, p. 2029-2049 (also available at 

http://dx.doi.org/10.1016/j.csr.2006.07.022).

Butman, Bradford, Dalyander, P.S., Bothner, M.H., Borden, 

Jonathan, Casso, M.A., Gutierrez, B.T., Hastings, M.E., 

Lightsom, F.L., Martini, M.A., Montgomery, E.T., Rendigs, 

R.R., and Strahle, W.S., 2009, Long-term oceanographic 

observations in Massachusetts Bay, 1989–2006: U.S. 

Geological Survey Data Series 74, version 3.0, DVD-ROM. 

(Also available at http://pubs.usgs.gov/ds/74/.)

Butman, Bradford, Dalyander, P.S., Bothner, M.H., and Lange, 

W.H., 2008, Time-series photographs of the sea floor in 

western Massachusetts Bay, 1996–2005: U.S. Geological 

Survey Data Series 266, version 1.0, DVD-ROM, (Also 

available at http://pubs.usgs.gov/ds/266/.)

Harris, C.K, Butman, B., and Traykovski, P., 2003, Wintertime circulation and sediment transport in the Hudson Shelf 

Valley: Continental Shelf Research, v. 23, no. 8, p. 801–820.

Signell, R.P., Jenter, H.L., and Blumberg, A.F., 2000, Predicting the physical effects of relocating Boston’s sewage 

outfall: Journal of Estuarine Coastal and Shelf Science, 

v. 50, p. 59–72.

Signell, R.P., 2007, Effluent dilution simulations in Massachusetts Bay: An evaluation of relocating greater Boston’s 

sewage outfall, in Bothner, M.H., and Butman, B., eds., 

Processes influencing the transport and fate of contaminated sediments in the coastal ocean–Boston Harbor and 

Massachusetts Bay: U.S. Geological Survey Circular 1302, 

section 5, p. 34–37. (Also available at http://pubs.usgs.gov/

circ/2007/1302/.)
Prepared by the West Trenton Publishing Service Center.

For more information concerning this report, contact:

Director

U.S. Geological Survey

Woods Hole Coastal and Marine Science Center

384 Woods Hole Road

Quissett Campus

Woods Hole, MA 02543-1598

bschwab@usgs.gov

508-548-8700 or 508-457-2200

or visit our Web site at:

http://woodshole.er.usgs.gov/
Bothner and others—Data Collected in Massachusetts Bay during a Large Discharge of Total Suspended Solids in August 2002—Open-File Report 2010–1050