1991

Massachusetts Water Resources Authority · from the MWRA · 110 pages · 5.9 MB
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January 1992

The State of
BOSTON HARBOR:
1991

Massachusetts Water
Resources Authority

Environmental Quality Department
Technical Report No. 92-3

THE STATE OF BOSTON HARBOR: 1991

Andrea C. Rex
; Kenneth E. Keay
a Wendy M. Smith
- Jerome J. Cura
| Charles A. Menzie
vt Margarete S. Steinhauer
Michael S. Connor

wh January 1992

Technical Report No. 92-3
Environmental Quality Department
Massachusetts Water Resources Authority
100 First Avenue

a Charlestown Navy Yard
af Boston, MA 02129

& (617) 242-6000

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Citation:

Rex, A., K. Keay, W. Smith, J. Cura, C. Menzie, M. Steinhauer, and M. Connor. 1992.
The state of Boston Harbor: 1991. MWRA Enviro. Quality Dept. Tech. Rpt. Series No.
92-3. Massachusetts Water Resources Authority, Boston, MA. 106 pp.

————— ee ——————

PREFACE

In this report, we provide information on the current condition of
Boston Harbor and compare it to the condition we reported last year. Our
intent is to give an overview of the state of scientific knowledge about the
harbor. For more detailed information, contact the library of the
Massachusetts Water Resources Authority (MWRA) for copies of MWRA
technical reports.

The report is organized around the issues we believe to be of most interest
to the concerned citizen, After summarizing some of the information
: necessary to understand conditions in the harbor, we look at four
i, primary concerns expressed by the public: Is Boston Harbor safe for
swimming and boating? Is it safe to eat the harbor's fish and shellfish?
Are fish and other marine resources being adequately protected from the
effects of pollution? What about the aesthetic conditions--is the harbor a
resource that people can enjoy?

As a way of summarizing the information, we grade the factors that must

be considered in answering the four questions. Each factor has two

grades, one representing the current state of the harbor the other, and

last year's grade. In the final section of the report, we compile all the

grades into a report card for Boston Harbor and explore the question of

d how the harbor is expected to improve now that the discharge of sludge to
the harbor has stopped.

| We have adjusted the grading system based on the comments that we
/ received from a wide variety of readers of last year's report. As a result of

concerns about the uses of the harbor in areas without beach access, we
a} have separately evaluated the health risks of boating. Much of the

og grading in last year's report card was based on the expert opinion of our
i staff and outside reviewers. This year we have quantified the criteria for
the grade in each category.

.4 The information in this report is drawn from many different sources.
, The MWRA Environmental Quality Department supports and
participates in monitoring efforts that involve cooperation between the
Commonwealth and a variety of public and private research
institutions. In addition, many studies with information relevant to the
harbor have been or are being conducted by other organizations. These
studies include routine monitoring performed by various State and local
agencies, small-scale research by local universities or environmental
organizations, and large national programs funded by the Federal
government. Institutions involved in long-term studies of harbor
, quality include the Massachusetts Institute of Technology, the National
J Oceanic and Atmospheric Administration (National Status and Trends
Program), the New England Aquarium, Northeastern University, the
® University of Massachusetts at Boston, the U. S. Geological Survey, and
my the Massachusetts Bays Program.

MWRA's Environmental Quality Department provides a valuable service
by synthesizing the results of these and other studies to advance both the
theoretical and the practical knowledge of conditions in the harbor. This
knowledge enables MWRA to make environmentally sound and cost-
effective decisions that benefit Boston Harbor.

Massachusetts Water Resources Authority
Environmental Quality Department
Charlestown Navy Yard
100 First Avenue
Boston, MA 02129

. (617) 242-6000

Grading system used for the Boston Harbor report card

A EXCELLENT: Consistently maintains conditions characteristic
of other clean coastal sites (e.g., Provincetown Harbor).

B_ GOOD: Frequently is better than Federal and State water quality
standards and expectations for an urban estuary (e.g., some of
Puget Sound).

C SATISFACTORY: Complies with Federal and State water quality
standards and meets expectations for an urban estuary (e.g., San
Francisco Bay).

D POOR: Sometimes fails to comply with existing standards or meet
expectations for an urban estuary; some uses of the harbor
are maintained (e.g., Boston Harbor last year).

F FAILING: Consistently fails to comply with Federal and State
water quality standards or meet expectations for an urban estuary;
there is obvious environmental degradation and uses of the harbor
are lost (e.g., New York Harbor and New Bedford Harbor).

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REPORT CARD FOR Boston Harbor
1991 1990
IS IT SAFE TO SWIM AND BOAT?
Swimming D+ D
Boating B (not graded)
IS IT SAFE TO EAT FISH AND SHELLFISH?
Shellfish: Pathogens D+ D-
Fish: Organic contamination C- C-
Fish: Metal contamination B- B-
ARE MARINE RESOURCES PROTECTED?
Sediment contamination D- D-
Water quality: Oxygen c C-
Water quality: Toxic contamination B- B-
Fish disease D- D-
Seafloor Animals D D-
IS THE HARBOR AESTHETICALLY PLEASING?
Aesthetics , D D
OVERALL GRADE C- D+

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EXECUTIVE SUMMARY

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This report updates last year's report on the
environmental status of Boston Harbor and summarizes
its condition in a report card. For each factor evaluated,
both last year's and this year's grades are recorded. Asa
result of public response to last year's report, we have
slightly changed the questions to be graded and added
more extensive quantification to the grading criteria.

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Throughout the report we find that environmental
conditions vary from one part of the harbor to another. In
general, the inner harbor and parts of the northwestern
outer harbor are most affected by contamination, and the ?
southeastern portions of the outer harbor are least ‘
affected. The environmental status of the harbor is

assessed by examining four questions that respond to

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some common concerns: 7
¢ Is Boston Harbor safe for swimming and boating? y
* Is it safe to eat fish and shellfish caught in the harbor? 4
¢ Are marine resources in the harbor satisfactorily °
protected from pollution? . q

¢ Is the aesthetic condition of the harbor pleasing?

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The factors that are graded to make up the report card are
grouped under these four questions.

Is Boston Harbor Safe for Swimming and Boating?

. recent improvement of the state of the harbor. While most

1990: D parts of the inner harbor, landward of Commonwealth

1991: De Pier, continue to have problems, many of the swimming

. beach areas are showing more improvement than we oy
anticipated last year, due to improved operation of the id
Deer Island treatment plant and more aggressive :
maintenance of the collection system by the Boston Water ra
and Sewer Commission. ‘

Swimming Beaches We consider beach condition to be the best indicator of the ]

Executive Summary

Most boating activities provide less exposure to the water

Boating : than swimming. Boating, therefore, receives a better
grade than swimming. The highest boating risks are faced

1990: No grade by windsurfing enthusiasts in the Charles River basin.

1991: B Except in the plumes of the treatment plant discharges,

the quality of the harbor for boating is quite good.

Is It Safe To Eat Harbor Fish and Shellfish?

Because of pathogen contamination, none of the shellfish

Shellfish: beds in the harbor can be harvested except by master

Patho gens diggers who take their harvest to depuration plants for
purification in clean water. The Division of Marine

1990: D- Fisheries can usually find beds that meet standards for

1991: D+ this type of harvesting during dry weather. While

. bacterial contamination of the harbor is declining,
shellfish standards are stricter than swimming
standards, so the harbor receives a lower grade.

Throughout the harbor, concentrations of
\ polychlorinated biphenyls (PCB) in lobster tomalley (or
. Fish: Organic hepatopancreas) exceed the standard established by the
} Contamination U. S. Food and Drug Administration (FDA) as acceptable.
- Concentrations of PCBs in fish and shellfish sometimes
y 1990: C- exceed U. S. Environmental Protection Agency (EPA)

_ 1991: C- guidelines for risk assessment, as do concentrations of
, polynuclear aromatic hydrocarbons (PAH).

! : Metal concentrations are elevated in fish and shellfish in
: the harbor, but not to the extent that human health

= Fish: Metal standards are violated.
; Contamination
1990: B- For heavy metals as well as organic contaminants, the
1991: B- contamination of fish and shellfish is expected to
improve very slowly. Changes since last year have been
very small.

a Are Marine Resources Protected?

Fish and sea-floor animals were chosen to represent the
status of living resources in the harbor. These groups
ih contain commercially valuable species and are likely to
exhibit the effects of living in a contaminated
a environment. Contamination in both the water column
and the sediments was assessed because of the possible
‘ effect on these species. :

~ vi

Sediment
Contamination

1990: D-
1991: D-

Water Quality:
Oxygen

1990: C-
1991:'C

Water Quality: Toxic
Contamination

1990: B-
1991: B-

—eae——————

Fish Disease
1990: D-
1991: D- !

Seafloor
Animals

1990: D-
1991: D

Executive Summary

Most of Boston's inner harbor contains sediments with
levels of organic and metal contamination similar to
those found in other urban harbors of the United States.
In Hingham and Hull Bays (the southeastern harbor),
contamination concentrations are only moderate,
whereas areas in the northwestern and central portions of
the harbor are intermediate in degree of contamination.
Changes in sediment contamination will take several
years to be observable.

Water in the inner harbor occasionally fails to meet
standards for dissolved oxygen, but concentrations rarely
approach levels that can adversely affect marine life. In
the outer harbor, water quality standards are generally
met, but concentrations of dissolved oxygen are
sometimes depressed.

Water quality criteria for the protection of the organisms
living in the harbor from toxic pollutants are met most of
the time. This is particularly true in the outer harbor,
which is well flushed with water from Massachusetts Bay.
The concentrations of toxic pollutants are less in Boston
Harbor than in many other northeast urban estuaries.

Boston Harbor has been noted for the high incidence of fin
rot and tumors in its winter flounder. The incidence of
tumors in flounder and pre-tumor conditions for tumors
has declined for the last five years, but changes in the past
three years have been only slight.

Some areas of the inner harbor and Winthrop Bay are
nearly devoid of seafloor animals, but large portions of
the southeastern outer harbor have quite active and
diverse bottom-dwelling communities. If seafloor
animals are limited by the concentrations of toxic
contaminants found in the sediments, their recovery
should be very slow, like that described for sediment
contaminants. Alternatively, benthic communities may
be more affected by the availability of oxygen for
respiration, implying that they might recover more
rapidly.

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Executive Summary

Aesthetics

1990: D
1991: D

Overall

1990: D+
1991: C-

Is the Harbor Aesthetically Pleasing?

Discharge plumes from the treatment plants have a
noticeable odor and color that mar the aesthetics of the
harbor. Last year volunteers found less trash per unit area
in Boston Harbor than in the previous year. However,
more discarded tampon applicators are still found on
Boston Harbor beaches than along any other coastline in
the United States. This major factor prevented the grade
from improving.

What Is the Harbor's Overall Grade?

Our 1991 assessment of the condition of the harbor shows
improvement compared to last year. Although the
improvement is small, and partially due to our more
quantitative grading scheme, we are excited that any
recovery is visible at this early stage of the Boston Harbor
Project. Most of the data recorded in this report were
gathered in 1988-1990, and therefore reflect past
conditions. Even so, bacterial contamination of the
harbor from CSOs and the treatment plants has
measurably lessened. Overall, the harbor is better for
swimming today than it has been in the last sixty years.
Now that sludge dumping has stopped, the water in the
outer harbor near the sludge outfall is noticeably clearer.
The sediments in Dorchester Bay and near the tip of Long
Island are beginning their recovery, though measurable
improvements may take several years.

Commercial ship traffic, the continuing problem of
stormwater runoff, wet weather CSOs and the legacy of
past pollution bound up in the sediment will prevent
Boston Harbor from attaining a pristine condition.
Nevertheless, we are already seeing signs that the harbor
is responding positively to the Boston Harbor Project.

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ACKNOWLEDGEMENTS

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The authors are grateful to the following people for their advice

and technical assistance: Jon Freshman, Michael Moore, 2
Richard Signell, Scott McDowell, Allan Michael, Robert Hillman, 4
Luisa Valiela, Eric Adams, Philip Gschwend, Gordon Wallace, and 3
Christine Werme.

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TABLE OF CONTENTS

1, THE PROBLEM AND THE PLAN. .........02e000005 lac eeeeeee eect teeennaeeeeeeees 1-1
Sources of Pollution in Boston Harbor ............ sede e eee e ee eneenenn eens 1-1
. Overview of the Plan to Improve Boston Harbor. ..........-. sees secre ence eee 13
: What Has Been Accomplished?..........2cceecee eee e teen teen cent eee eeee ees 1-3
The 1991 State of ‘Boston Harbor Report: "The Report Card". ........... 2.0005 14
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ae 2. UNDERSTANDING THE PROBLEM ..........eeseeeeeeeeeee Sec ee eee eeeeeeees 2-1
} Types of Contaminants and Their Sources. 0.0.0... cece eee cece ee eevaaeeeees 2-1
ey Fate of Contaminants in the Harbor. ....... 0 0c c ce eee eet ee teen eee ennees 2-5
: SUMMALY oo. ccccececee cece e cere eee e tenet eect teen eee e teen eenenee 2-10
3. IS BOSTON HARBOR SAFE FOR SWIMMING AND BOATING? ....... 00sec eeee 3-1
» Historical Context........ 00sec ccc e eee e eee e eee eee e ents een en ene eeeee 3-3
Effect of Recent Pollution-Control Activities on Water Quality ............. 34
- Mathematical Model of Harbor Pollution, Based on New Data............+.5 3-6
Water Quality for Recreational Use Varies among Different Areas of the
Harbor. oo... cece cece cece eee eee eee See ec eee eee eee e eee n serene renee 3-8
) REPORT CARD 20... cc cece cece eee e eee e nee c eee e nese ee eneeeeneeeeetaenes 3-11
4, IS IT SAFE TO EAT FISH AND SHELLFISH? ........ 0... e ces eecee en eeeseeeeeees 41
Pathogen Contamination in Shellfish 1.0.0.0... ccc ccc cece eee eee e eens 41
Toxic Chemicals in Fish and Shellfish ..... 0.0.0... c cece cece eee eee 43
; Metals in Seafood Species in Boston Harbor...... 0... cc eee cece eens 45
dj Organic Compounds in Flounder, Lobster, and Mussels from the Harbor..... 49
oy Summary of Chemical Contamination in Boston Harbor Fish and
; Shellfish... 0... c ccc cece eee ee cee rete rere cence eee e sense en eee ee eeeenes 49
7 REPORT CARD 0.0.00 .ccccseesecseseceeeueceeseeeteneseeeeeecsreeeeeeaes 4-12

5. ARE FISH AND OTHER MARINE RESOURCES BEING PROTECTED? ..........-. 5-1
Water Quality... ccc ccc ccc eee cee eee ee ee eee n eee e een e tee eeneeeeees 5-1
Sediments. 2.0.0... e cece ee eee cere eee een e eee een een n en en eens 54
Summary of Habitat Conditions in Boston Harbor. .......... 0.0. e cece cease 5-10
Living RESOUICES. 0... ccc eet eee teen e ee tenet teense tenn teens 5-10
Evaluation... ccc cece rennet eee eee nee n eens eee eneneee 5-15
REPORT CARD 2.0... cece cece cece e ee cee ee rene rere net e tenn eee e een seen ee 5-17

6. IS BOSTON HARBOR AESTHETICALLY PLEASING?.........0 cece eeeeeeseereneee 61
Scum and Sewage-Related Floating Debris. ........ 0... c ccc cect eee eee e ee eens 61
Effluent and Sludge.......... 0... cece cece e eee eee eee cee nett ence cence ene enes 61
Turbidity, 0.0... cece cece ee een ene nent eee e eee tree ee eee en eens 61
Marine DeDTIS.... 0... ccc ccc ence ene erent e nese een enee 62
Evaluation... ccc eee eee ee nee e eee tence ence ee tneeteneeteeaneee 63
REPORT CARD 2.0.0... cece ccc eee recente eee eee eee neta en te ne enneeees 63

7. COMPARISON AMONG DIFFERENT AREAS OF BOSTON HARBOR. ............-. 7-1

5 1) 5) 5d 2) Bd 8-1
Short-Term Recovery (Days to Weeks) .......... 0 cece deen e eer eneeeeeaneees 8-3
Medium-Term Recovery (Months to Years)...... 6... c cee e eect eee e eens 8-3
Longer-Term Recovery (Years to DecadeS)............cececeeeceeeneeeeencnes 83

APPENDIX 000. cc cece cence ne te eee e eee eee teen e nee eee eee eneee é-1
BIBLIOGRAPHY, 0... cece cece c cece eee een eee eee ener eee tent eee tee ee eee enteaes Bl
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Figure 1-1
Figure 2-1
Figure 2-2
Figure 2-3
Figure 2-4
Figure 3-1
Figure 3-2
Figure 3-3

Figure 3-4
Figure 4-1
Figure 4-2

Figure 4-3

Figure 4-4

Figure 4-5

Figure 5-1
Figure 5-2
Figure 5-3
Figure 5-4
Figure 5-5
Figure 5-6

Figure 5-7

LIST OF FIGURES

Time Line for Boston Harbor Project .... 6.6... c cece cece eee ee eee 1-2
Map of Boston Harbor Divisions ........... 0 ccs cece eee eee eee eeee 2-2
Pollution Sources to Boston Harbor........... 0c ce cee cece cence eee eee 2-4
Computer Model Showing the Flushing of Boston Harbor........... 26
Map of Erosional and Depositional Areas of Boston Harbor.......... 2-9
Bacterial Water Quality in Boston Harbor over 50 Years............-. 3-2
Fecal Coliform Counts in Fort Point Channel ............0:eeeeeees 3-7
Effect of a "3-Month Storm" on Fecal Coliform Counts in

Boston Harbor ......... cece cece eee een eee eee ene ee eee e een e ete enes 3-9
Beach Postings in Boston Harbor: 1989-1991 ......... 0. cece eee eee 3-10
Prohibited and Restricted Clam Beds in Boston Harbor ............. 42
Average Metals in Boston Harbor Seafood Compared to

Regulatory Limits 2.0... cece cece cece eee e een eee n ee en ee eneees 46
Metals Levels in Boston Harbor Mussels Compared to

Other Urban Harbors 00.0.0... cece cree eee e een een nee nanne 48
Organic Chemicals in Seafood from Boston Harbor............-.+++ 4-10

Organic Chemicals in Mussels within Boston Harbor and
Compared to Other Urban EstuarieS.......... 00. c cess eee e eee eeeees 4-11

Histograms of Dissolved Oxygen Measurements in Boston Harbor .. 5-2

Depths of Redox Potential Discontinuities in Boston Harbor......... 5-5
Patterns of Sediment Contamination in the Harbor ...............-. 5-7
Comparison of Sediment Contamination to Other Areas ........... 5-9
Declining Liver Lesions in Winter Flounder .............-.ceeeeees 5-12
Rocky Bottom Benthic Communities and Sewage Tracers from

Lovell Island to Nahant. ..... 0... ccc ccc eee een eee een eeeeees 5-14
Benthic Communities in the Harbor ......... 00. c cece eee eee eee 5-16

xii

Figure 7-1

Figure 8-1

Table 3-1
Table 3-2

Table 4-1

Table 4-2

LIST OF FIGURES, continued

Geographic Variation in Environmental Quality in Boston Harbor. . .

Relative Loadings of Sludge, Effluent and Other Sources of
Pollutants, 0... . cece cee eee ee cece cence eee e tenet eee e nee eee n cnet

LIST OF TABLES

Pumping Flow and "Choking Time”! at Deer Island Headworks . . .

Fecal Coliform Counts in the Water Near New CSO Treatment
Facihties 0.0... cee cece eee n ene ne ene eee ne eeeeeet

Restricted and Prohibited Productive Clam Beds in Boston Harbor. .

Average Concentrations of Contaminants in Edible Tissues of
Fish and Shellfish from Boston Harbor .........0+.+++-- bee beeeeeee

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FDA

MDC

NOAA
PAH
PCB

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LIST OF ACRONYMS

Biochemical oxygen demand ...........c.c cece cece eee eee e ees seeeee 3-5
Boston Water and Sewer Commission ..........0 0000 c cece eee eee 1-4, 3-1
Combined sewer overflow ...... 0... ccc cece cece eee cence eee e eens 2-3
Dichlorodiphenyltrichloroethane .......... 00. c cece cece eee eee 4-7
Dissolved OXyZeM .... ccc cece cence eee nee eee nent eee teeen eens 5-1
United States Environmental Protection Agency ..............0006. 4-4
United States Food and Drug Administration .............. 0.0 eens 4-4
Metropolitan District Commission........... Vance c eect eens scene 3-8
Massachusetts Institute of Technology... .. penne eee ee eee eee eees 3-8
Massachusetts Water Resources Authority ............... veceeeeees 1-1
National Oceanic and Atmospheric Administration ..............6. 4-7
Polynuclear aromatic hydrocarbon. ......... eee e eect eee eee eee 2-3
Polychlorinated biphenyl ........... 6. c cece cece eee eee eee e ene 4-7
Redox potential discontinuity... 0... 0... cee cece cece eee e eee eee 5-6
xiv

RSE

1 THE PROBLEM AND THE PLAN

Boston Harbor has been a busy port, an abundant source of food from the
sea, a place for relaxation and appreciation of natural beauty--and a
place for disposal of human wastes--for centuries. As the Boston urban
area has grown, the harbor has received an increasing volume of sewage;
on and an increasing number of people have discovered an appreciation for
\ the harbor as an aesthetic and recreational resource. Public concern
over the impacts of sewage disposal on these other valued uses of the
harbor has grown over the past decades, as beaches have been posted,
shellfish beds closed, and visible sewage wastes impaired uses and
enjoyment of the waters. The Massachusetts Water Resources Authority
(MWRA) was created in 1985 in large part to respond to the problem of
sewage pollution in the harbor by building modern sewage treatment
eA facilities.

Sources of Pollution in Boston Harbor

Boston Harbor and its tributaries have historically received most of the
domestic and industrial wastes from the city and its surrounding
communities. Today, more than 500 million gallons of domestic and
industrial wastes are transported through the MWRA sewer system to the
Deer Island and Nut Island sewage treatment plants each day. These two
outdated facilities provide only primary treatment, a process that
im separates the solid waste (sludge) from the liquid waste (effluent). The

\ effluent is disinfected by chlorination, and the sludge is digested to
reduce volume and kill microbes. Up until December 1991, both sludge
and effluent were discharged into the harbor, with sludge being
. discharged on the outgoing tide. Although sludge discharges have ceased,
is} inadequately treated sewage is still the major source of pollution in
: Boston Harbor.

: In addition to discharges from the treatment plants, sewage is discharged
? by over 80 combined sewer overflows (CSOs). Boston and some of the
: surrounding towns have sewer systems designed to carry both sewage and
stormwater (combined sewage) to the treatment plant. When very heavy
rains fall, overloading the capacity of the sewerage system, the excess
volume is discharged from pipes designed for this purpose into the
harbor and its tributary rivers. Although some combined sewage
. receives minimal treatment, screening and chlorination, before
a discharge, CSOs are a significant source of raw sewage to the harbor.

Other sources of contamination also degrade conditions. in Boston
Harbor. Litter and chemicals (e.g.,oil) are carried in runoff from streets
4 and land. Tributary rivers also carry a load of litter, toxic

wee contaminants, and particles of soil and organic matter into the harbor.
The atmosphere contributes airborne pollutants, especially lead.. A few
industrial discharges also flow into the harbor. Ship and boat traffic in
the harbor and runoff from waterfront construction projects add to the
pollutant load.

—

1-1

The Problem and the Plan

1988 ‘89 ‘90 94 ‘92 93 94 ‘95 96 '97 98 ‘99 = 2000

) jn ——— ~~

@ Cease discharge of scum from Deer Island
[] Improve existing facilities

@ Cease discharge of scum from Nut Island

Construct sludge facilities
4

Interim facilities completed; Permanent sludge facilities
discharge of sludge to harbor ceases —_ begin operation

Construct new primary
treatment facilities

Full primary treatment begins

Construct outfall

Discharge of effluent
to harbor ceases

Construct secondary treatment facilities

4 4 |
Battery A Battery B Batteries
Y C&D
Control CSOs
| q
Monitoring/system optimization plans submitted

Final CSO facilities plan submitted

Figure 1-1. Time line for Boston Harbor Project. In response to the 1985 Federal Court order,

MWRA negotiated a plan and a schedule for cleaning up Boston Harbor.

1-2

———— a ——— pe ——— pe ——— a ———

1988 ‘89 ‘90 91 92 ‘93 94 ‘95 '96 ‘97 ‘98 ‘99 2001

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The Problem and the Plan

Overview of the Plan to Improve Boston Harbor

Although numerous sources contribute to pollution in Boston Harbor,
the largest source of contamination and the focus of most public concern
is sewage. MWRA's mission is specifically to comply with the Clean
Water Act, which has the goal of making U.S. waters "fishable" and
"swimmable," by providing proper treatment and disposal of sewage.
Litigation over pollution of the harbor resulted in the development of a
Federal court-ordered schedule to plan and build proper sewage
treatment facilities (Figure 1-1). MWRA is now well into implementation
of this ambitious Boston Harbor Project.

Key components of the Boston Harbor Project are:
¢ Improvements to existing wastewater treatment facilities.
* Building of facilities for processing sludge to fertilizer.

* Construction of new, primary and secondary facilities for wastewater
treatment and construction of an ocean outfall.

¢ Reduction of combined sewer overflows and treatment of combined
sewage.

¢ Reduction in the amount of toxic chemicals entering the sewer system.

Progress has already been made in each component of the plan.

What Has Been Accomplished?

Fast-track Improvements

The Boston Harbor Project was designed to be implemented in phases, so

that some sources of harbor pollution would be abated quickly. These

"fast-track" improvements to existing facilities have already been made

by MWRA:

* More reliable and effective chlorination of the effluent.

¢ Removal of scum (oil and floating debris) from the effluent.

¢ Improvements to sludge digesters.

* Increased pumping capacity of wastewater flow to the Deer Island
treatment facility, This means that more sewage reaches the
treatment plants during rainstorms, decreasing combined sewer
overflows.

¢ Improvements to the combined sewer infrastructure: construction of
three new CSO treatment facilities, repair of tidegates and regulators.

The Problem and the Plan

1-4

In addition, the Boston Water and Sewer Commission has identified
illegal sewer connections to storm drains, and the MWRA has
eliminated many of these sources of pollution.

Sludge Dumping in the Harbor Ended in December, 1991

As well as the "fast-track" improvements, MWRA recently marked a
major milestone in the Boston Harbor Project, beginning operation of
the processing plant that converts the sludge to fertilizer. The discharge
of sludge into the harbor stopped in December, 1991. After decades of
receiving the pollutants and sediments in sludge, the harbor will begin a
natural cleansing process--in some locations contaminated sediments
will be buried in clean sediments, and in other places they will be
resuspended and gradually flushed out of the harbor.

The 1991 State of Boston Harbor Report: "The Report Card"

In 1990, the MWRA published the first "Report Card," which summarized
the pollution problems in the harbor and MWRa's role in addressing
problems caused by improper sewage disposal in the harbor. The report
was organized around the issues believed to be the most important to the
concerned citizen. These issues are:

¢ Can the harbor safely be used for swimming and boating?

¢ Is it safe to eat fish and shellfish caught in the harbor?

* Are fish and other marine resources of the harbor being protected?

¢ Is the aesthetic condition of the harbor pleasing ?

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2. UNDERSTANDING THE PROBLEM

Understanding the pollution problems caused by sewage discharges into
Boston Harbor requires some knowledge of the oceanographic features of
- . the harbor. Boston Harbor covers about 47 square miles of bays and
rah tidal estuaries (Figure 2-1). The harbor is shallow, between 3 and 30 feet
‘4 deep, except in President Roads and Nantasket Roads, the two shipping
channels, where water depths approach 60 feet. Small islands are
scattered throughout the harbor.

Boston Harbor is customarily separated into two main areas, the inner

: harbor and the outer harbor. However, the harbor is a complex system of
md many small bays and open-water areas that are variously influenced by
ot . different sources of contamination and that have different physical
properties which, in turn, influence the fate of contaminants. Asa
result, environmental quality can vary throughout the harbor and
4 different areas may be more or less suitable for some uses. For these
reasons, subdivisions of the harbor will be discussed separately with
respect to the four major issues. The divisions of the harbor and two
tributary areas (Figure 2-1) referred to in this report are:

e Inner harbor

¢ Northwest harbor (Dorchester Bay and areas north of Long Island)
\ ¢ Central harbor (Quincy Bay and Nantasket Roads)

¢ Southeast harbor (Hingham Bay)

Types of Contaminants and Their Sources

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The major groups of contaminants that degrade the environmental
quality of Boston Harbor are:

1, Suspended Solids -- small particles of inorganic materials such as

‘ sand and clay: living organisms, such as bacteria and
phytoplankton; and organic matter. These particles, which are
suspended in the water, can come from natural sources (, land
runoff, rivers, bottom sediments) or man-made sources (e.g.,
effluent and sludge). Suspended solids are important in evaluating

| water quality because toxic materials (see item 5 below) often

id attach to particles. Water with a heavy load of suspended solids is

also murky and unattractive.

al 2. Oxygen-Consuming Organic Matter -- decomposing organic
ve material that depletes the oxygen necessary to support marine life.
In Boston Harbor, oxygen-consuming matter is commonly
1 associated with effluent and sludge but it also is produced by
7) marine plant growth (see item 4 below).

Understanding the Problem

= OUTER NORTHWEST

Figure 2-1. Map of Boston Harbor divisions. The harbor has been divided into sections so each
can be considered separately.

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Sewage sludge and
effluent are major
Sources of most
contaminants

Different areas of
the harbor are
affected by
different types of
pollution

Understanding the Problem

3. Pathogenic Microorganisms -- disease-causing microorganisms
(viruses and bacteria). Pathogens are found in untreated sewage.
Combined sewer overflows (CSOs), which under certain conditions
discharge untreated sewage, are the most important source of
bacteria to Boston Harbor. Illegal cross connections of sanitary
sewers to storm drains can also be a significant source of
pathogens. The presence of pathogens is often indicated by the
presence of fecal coliform and enterococci bacteria.

4. Nutrients -- chemicals that are essential for the growth of
phytoplankton. In excess, nutrients such as carbon, nitrogen and
phosphorus cause eutrophication, a condition of excess plant
growth. As the excess plant material decays, oxygen in the water
can be depleted (see item 2 above). Effluent and past sludge
discharges have been the two significant sources of nutrients to the
harbor, although runoff, river input, and CSOs also contribute
nutrients.

5. Toxic Materials -- metals and organic chemicals that are
poisonous or that can accumulate in living tissue to cause long-
term effects or move up through the food chain. Most toxic
chemicals enter the sewage system through industrial discharges,
but household wastewater and storm runoff are also important
sources.

The above contaminants enter Boston Harbor from sewage effluent and
sludge, CSOs, rivers, stormwater, and the atmosphere. In the harbor,
most kinds of contaminants, except for pathogens, come principally
from effluent and sludge discharges. CSOs and failed sewer lines are the
major source of pathogens. Rivers, CSOs, stormwater runoff, and
industrial discharges into the sewer system are significant sources for
suspended solids and certain toxic chemicals. Direct discharges of
industrial waste into the harbor and its tributary rivers are less
significant than other sources of contamination. Deposition from the
atmosphere is an important source for a few chemicals, particularly lead
and polynuclear aromatic hydrocarbons (PAHs).

Because of the location of sources and the physical differences among
parts of the harbor, the key pollution problems vary among the
geographic areas of the harbor. For example, in parts of the inner
harbor, a warm, fresh, lighter water layer cuts off the underlying cold,
saltier bottom water from the atmosphere and results in frequent
depletion of dissolved oxygen, which is not observed in the well-mixed
outer harbor. Fish diseases, which can result from exposure to toxic
contaminants present in sewage effluent and sludge, are more prevalent
on Deer Island Flats, near the sewage outfall, than in other areas of the
harbor. High bacterial counts in the inner and northwest harbor areas
are due to CSOs, while high counts in the southeast harbor are caused by
contaminated stormwater.

2-3

2-4

Massachusetts

Bay

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Figure 2-2. Pollution sources to Boston Harbor. Pollution sources to the harbor include sewage

effluent, sewage sludge, and combined sewer overflows.

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About a sixth of
the water in
Boston Harbor is
flushed out during
a single tidal
cycle

The deep shipping
channels are well
flushed; shallow

bays flush more
slowly

Understanding the Problem

Fate of Contaminants In The Harbor

As described above, the primary sources of contamination to the harbor
are sewage effluent and sludge, and CSOs which are located throughout
the inner and northwest harbor areas (Figure 2-2). What happens to
contaminants from these sources after they enter the harbor? Many
contaminants adhere to small particles; these can either settle to the
bottom of the harbor or can leave the harbor and eventually settle
elsewhere. Other contaminants, such as nutrients, tend to be dissolved
in--and move with--the water. Dissolved pollutants do not accumulate
in the harbor, but their concentrations in harbor water may be high
because of the large load entering the harbor's small volume each day.
Whether contaminants are a problem in an area of the harbor depends
on whether they are attached to particles, the time it takes for particles
to settle, and the rate at which harbor water is exchanged with water
from offshore.

Water Movement

Flushing in coastal harbors depends largely on freshwater inflow, tides,
wind, and depth. Boston Harbor is unique because more than one-half of
its freshwater inflow, 20 cubic meters per second, comes from sewage
effluent, which enters at the mouth rather than at the head of the
estuary. By comparison, the combined freshwater flow of the Charles,
Mystic, Chelsea, and Neponset Rivers is about 18 cubic meters per second.
Water circulation in the harbor, however, is dominated by strong tides;
the average tidal range is 2.7 m (9 ft). About 17% of the water in the
harbor is flushed out during a single tidal cycle. Overall, most of the
harbor water exchanges with Massachusetts Bay water in about 9 days;
more in some areas of the harbor, less in others.

Water in Quincy Bay, Dorchester Bay, and Deer Island Flats in the
northwest harbor does not exchange rapidly with Massachusetts Bay. In
contrast, the deep channels at the harbor entrances, President Roads and
Nantasket Roads (Figure 2-2) are much more energetic and well flushed.
Because the large volume of tidal flow exits the harbor primarily through
President Roads and Nantasket Roads, very strong currents develop
there, resulting in vigorous mixing in these locations. Hingham Bay in
the southeast harbor is also well flushed due to the considerable influx of
Massachusetts Bay water through Nantasket Roads. Figure 2-3 shows
graphically how the tides mix Boston Harbor water with Massachusetts
Bay water. Water in the southeast harbor exchanges with Massachusetts
Bay through Nantasket Roads; water in the inner harbor and the
northwest harbor exchanges through President Roads. Quincy Bay,
although adjacent to Nantasket Roads, appears to exchange primarily
through President Roads. In general, the southern part of the harbor,
with the exception of Quincy Bay, is better flushed than the northern
part.

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Understanding the Problem

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Figure 2-3. Computer model showing the flushing of Boston Harbor. A computer model was ig
used to investigate the flushing of Boston Harbor, by defining "Boston Harbor Water" as that
water which lay west of a line connecting Deer Island to Hull. The figure shows, 3.6 days later,
how much of the water in each area of the harbor and Massachusetts Bay is made up of that
original "Boston Harbor Water." The channels at the harbor entrances are well flushed, while
the inner harbor and other small bays have not exchanged much water with Massachusetts
Bay. Figure courtesy of R. Signell,

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Most sewage
particles leave the
harbor when first

discharged or
after
resuspension

Understanding the Problem

Some parts of Boston Harbor are relatively calm and other areas are very
dynamic. The harbor's strong tides and numerous islands stimulate
mixing of the water in most areas. Recent field studies and modeling
results suggest that water movement and transport of particle-bound
contaminants in Boston Harbor can vary considerably over very short
distances. An example is the movement of water near the Nut Island
sludge outfall on Long Island. Field observations suggest that, on an
outgoing tide, this water stays near Long Island despite its proximity to
the strong currents in President Roads. On the flood tide, the water near
Long Island and the sludge plume could move south toward Nantasket
Roads. As a result, the sludge did not necessarily move out of the harbor
through President Roads, but was dispersed by strong flows from
multiple directions.

During ebb tides, the effluent from the Deer Island treatment plant mixes
with seawater in President Roads and is transported out of the harbor.
Effluent plumes from the Nut Island treatment plant are vigorously
mixed with water from the western part of Nantasket Roads in the ©
central harbor. Studies using drifters show how water parcels from the
outfalls can move on a particular day; for example, during a single ebb
tide, effluent discharged into Nantasket Roads can reach Massachusetts
Bay. To understand the net effect of several tidal cycles, we can use a
computer model; such a model indicates that Nantasket Roads and
Hingham Bay are the areas most affected by discharge from the Nut
Island effluent outfallis. However, the wind can play an important role
which is not captured in the model; field studies have shown that a west
wind can occasionally move the Nut Island plumes into Portuguese Cove
on Peddocks Island.

Particle Movement

Most toxic chemical contaminants tend to adhere to small particles in
effluent and sludge. Unlike bacteria, which generally remain harmful
for only a few days in the marine environment, trace metals and organic
compounds are persistent. Contaminant-laden particles can accumulate
in quiescent areas of the harbor, resulting in localized high
concentrations of pollutants.

Because much of the harbor is effectively flushed, it appears that most
toxic contaminants introduced by sewage treatment plant discharges do
not settle in the harbor. A recent computer modeling study predicted that
as little as one-quarter of the contaminant particles introduced by
sewage discharges are deposited in the harbor. This prediction is borne
out by measurements of the sludge tracer, spores of the bacterium
Clostridium perfringens, in Massachusetts Bay sediments. Although the
concentrations of Clostridium perfringens spores in Massachusetts Bay
sediments are generally 10-50 times lower than concentrations in
Boston Harbor, the sludge tracer is spread out over a large area of the
Bay. In fact, concentrations in western Massachusetts Bay are as high as
the levels measured in the southeast harbor; this result indicates that a
considerable amount of sludge was leaving the harbor and affecting
Massachusetts Bay.

2-7

Understanding the Problem

2-8

Sediment Deposition

Particle-bound contaminants that are not flushed out of the harbor
eventually settle to the bottom in areas of the harbor that favor
deposition. Depositional areas occur where there are depressions in the
sea floor, where water is shallow, or where currents are weak. The
sediment on the harbor floor consists primarily of natural particles that
enter the harbor from offshore, or are created by erosion of the harbor
shoreline. Particles from sewage effluent, sludge, and CSOs are deposited
along with these "clean" particles throughout the harbor. The most
contaminated bottom sediment is found in depositional areas, especially
the inner harbor and close to sources, such as the Nut Island sludge
outfall at the tip of Long Island. A computer model of deposition predicts
rapid sediment accumulation in the inner harbor, moderately rapid
accumulation over Deer Island Flats, and minimal sedimentation in
President Roads. Swift tidal currents in the latter area scour away fine
sediments, leaving heavier sand and gravel behind. In general, much of
the central harbor and northwest harbor, and most of the southeast
harbor, are depositional; the deep shipping channels, however, are
erosional or have both processes occurring at different times, and
erosion also occurs around the shorelines (Figure 2-4).

Under the influence of a storm or an unusual tide, particle-bound
contaminants in the surface layer of the bottom sediments can be
resuspended into the water, carried to a different location, and sink
again. This process of resuspension and transport moves contaminants
away from their sources and even out of the harbor. Contaminants
attached to fine sediments are re-deposited on shallow mud flats or in
deep less-energetic parts of the harbor and eventually become
incorporated into the bottom sediment.

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Understanding the Problem

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Figure 2-4, Map of erosional and depositional areas of Boston Harbor. This map, from the U.S.
Geological Survey, show the areas of the harbor in which bottom sediments are swept away
(erosion) or accumulate (deposition). In many areas, both processes occur at different times
(sediment reworking). Figure form Knebel et al, 1991.

2-9

Understanding the Problem

2-10

Summary

Past discharges of sludge and the continuing effluent discharges are the
major sources of pollution in Boston Harbor. Types of contaminants
that contribute to water-quality problems in the harbor include (1)
suspended solids, (2) oxygen-consuming organic matter, (3) pathogenic
microorganisms, (4) nutrients, and (5) toxic materials. Although
effluent, sludge, and CSOs include all of these contaminants, other
sources also contribute to the total contaminant load.

Because most contaminants are associated with particulate material,
they can either be flushed out of the harbor under the influence of tides
and other currents, or they can drop out of the water column and settle on
the bottom. Physical and oceanographic features in different parts of the
Boston Harbor influence the fate of the contaminants. Based on the most
recent studies, the majority of particle-bound contaminants are
transported out of the harbor; the material that remains settles in
depositional areas of the harbor (e.g., the inner harbor, Deer Island .
Flats). Resuspension processes, induced by storms, large tides, or strong
currents, move particle-associated contaminants, that may have
originally been deposited near their source, to distant parts of the harbor
or even out of the harbor. The net result of these interacting processes is
a patchy distribution of contaminants in sediments throughout the
harbor and the development of "hot spots" of contamination in a few
localized areas (e.g., Deer Island Flats).

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3. IS BOSTON HARBOR SAFE FOR SWIMMING
AND BOATING?

High levels of
sewage indicator
bacteria in the
harbor are
associated with
rain

Many people enjoy Boston Harbor's waters and beaches for swimming
and recreational boating, and the impairment of these uses by sewage
contamination has provoked public concern. The greatest hazard from
recreational use of sewage-polluted waters is the risk of contracting
infectious diseases (stomach ailments, as well as eye, ear and skin
infections can result from swimming-associated exposure).
Unfortunately, the major sources of untreated sewage to Boston Harbor--
combined sewer overflows and contaminated storm drains--discharge
along the shoreline, often at swimming beaches. The inner harbor and
open-water areas of the outer harbor, used intensively for boating, can
potentially be affected by CSOs and effluent or sludge from the treatment
plants.

The greater the number of sewage bacteria and viruses in the water, the
more likely it is that people swimming in the water will be exposed to an
infection. As is true for all pollutants in the harbor, many factors affect
the counts of bacteria in the water. Important factors are: the volume
and concentration of sewage discharged into the water, whether or not
the sewage is disinfected, how far away the source fs, how long it has been
since the discharge, the patterns of water circulation, the temperature
and salinity of the water, the season, the time of day, and the stage of the
tide. Probably the single most important factor affecting bacteria levels
in the harbor is rainfall, which washes sewage from storm drains and
combined sewer overflows into the water. Heavy rains can cause
overloading of the treatment plants, forcing treatment plant bypasses.
The volume of rain falling, the location of the heaviest rain, and its
duration and intensity all interact in a very complex way both with
other environmental factors and the sewerage infrastructure (pipes,
pumps and treatment plants) to give a highly variable pattern of
bacterial pollution.

Over the past two years, several studies and monitoring activities done
by scientists, the Boston Water and Sewer Commission (BWSC), and
MWRA have significantly increased our understanding of this
interaction between the environment and the structure of the sewer _
system. This better understanding has developed at the same time that
concrete progress has been made in reducing harbor pollution, including
"fast-track" improvements at the sewage treatment plants, the
construction of new CSO treatment facilities, improved routine
maintenance of the system, and inspection and correction of illegal
sewer hook-ups.

The rest of this section will discuss new information about

microbiological pollution in Boston Harbor, and how changes in
patterns of pollution relate to abatement efforts.

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Is Boston Harbor Safe for Swimming and Boating?

Historical Context

To assess our current efforts to control pollution of the harbor, it is
helpful to put the newest study results in an historical context. To see if
there have been any broad trends in microbiological water quality over
time, a study was undertaken to analyze existing historical water-
quality data.

Sewage-Indicator Bacteria Used to Assess Water Quality

Two sewage-indicator bacteria are used to assess the quality of water in
Boston Harbor: :

Fecal coliform are bacteria normally found in the intestines of warm-
blooded animals. They occur in large numbers in raw, untreated
sewage. Although fecal coliform are not dangerous themselves, their
presence indicates that the water is probably contaminated with raw
sewage. Thus, it is likely that disease-causing bacteria and viruses
(pathogens) are also in the water. In Massachusetts, beaches are posted
as unsafe for swimming when the fecal coliform count exceeds 200
organisms per 100 ml of water. Fecal coliform bacteria have been used
as indicators of bathing-beach water quality for decades.

Enterococcus 1s a bacterium also found in the intestines of warm-blooded
animals, and in large numbers (but fewer than fecal coliform) in raw
sewage. Recent studies have shown that disease rates in swimmers in
marine waters correlate better with the counts of Enterococcus in the
water than with fecal coliform counts. This better correlation is
probably because Enterococcus is much hardier in salt water than fecal
coliform, tends to persist in the marine environment longer, and
therefore better mimics the distribution of viruses in the water. EPA
calls for an average count at marine bathing beaches of no more than 33
Enterococcus per 100 ml of water, and recommends posting a beach when
the Enterococcus count exceeds 104 per 100 ml.

Coliform bacteria counts (see box above) have been used by many
agencies to assess the risk to public health from sewage-impacted waters,
and many historical coliform count data have accumulated from studies
of Boston Harbor waters, dating from as early as 1905. Despite
differences in technical methodologies in the bacterial analyses done
over the course of time, and the large variability in data due to different
study designs, a clear trend emerged--bacterial water quality has been
improving in Boston Harbor over the decades.

Figure 3-1 shows that counts have decreased 10- to 100-fold over the past
50 years in the inner harbor, near Deer Island, Nut Island, Governors
Island, President Roads, Nantasket, Moon Head, and Dorchester Bay.
Dramatic improvements in water quality were related to sewage

Is Boston Harbor Safe for Swimming and Boating?

Fast-track

improvements at
treatment plants

3-4

have improved
nearshore and
offshore water

quality

treatment projects. For example, in 1939, the highest average bacterial
counts were found near Deer Island, Moon Head, Nut Island and Quincy
Bay (all were discharge points for untreated sewage). "B. coli' counts (an
approximate equivalent of fecal coliform counts) were on the order of
3,000-5,000 per 100 mL. In the 1960s, there were still high counts found
near Deer Island, Moon Head, President Roads and Governors Island, but
counts had decreased 10-fold near Nut Island and in Quincy Bay. This
improvement followed the opening of the Nut Island Treatment Plant in
1952. Similarly, the opening of the Deer Island Treatment Plant in 1968
was followed by a 10-fold decrease in counts near Deer Island and
Governors Island in the 1970s. In the 1980s, counts were generally the
same as in the 1970s, or lower, except in Quincy Bay and near Moon
Head. Bacteria counts in the inner harbor were dramatically lower in
the 1980s compared to the 1960s. Overall, these results contradict
popular, anecdotal opinion that water quality in Boston Harbor is worse
now than it has been in the past.

Effect of Recent Pollution-Control Activities on Water Quality

While the major projects for the proper treatment and disposal of sewage
(secondary treatment plant, outfall pipe, sludge treatment) are still under
construction, significant improvements to the treatment system have
been made through smaller projects. Two "fast-track" improvements
have been important to the microbiological water quality in the harbor:
installation of new pumps at Deer Island, and more reliable
chlorination at both Deer and Nut Island Treatment Plants. The new
pumps at Deer Island have greatly increased the amount of flow that can
be directed to the treatment plant during storms (Table 3-1). This
translates to reduced "choking" (excess flow diverted from the pumping
station, or "headworks") and fewer overflows from combined sewers.

Because of the variation in weather conditions from year to year, data
for more years are needed to tell whether there has been a statistically
significant reduction in bacteria counts in the water because of this
improved pumping. However, the indications are promising. For
example, in 1990, the BWSC measured the overflow volume from Carson
Beach CSOs and found that some large storms which were expected to
produce a large volume of overflow produced little or no discharge.

While improved pumping can decrease shoreline sources of sewage, more
reliable chlorination at the wastewater treatment plants has been
associated with a dramatic improvement in offshore bacterial water
quality. The extreme violations of fecal coliform water quality
measured near Deer Island by the New England Aquarium have not been
found since 1988, and water quality near Nut Island has been good since
1987. In 1990, the geometric mean fecal coliform counts in Quincy Bay
ranged from 1 to 7 per 100 ml, including samples collected in the Nut
Island effluent outfalls.

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Is Boston Harbor Safe for Swimming and Boating?

Table 3-1. Pumping flow and "choking time"! at Deer Island headworks
have improved dramatically.

Ave. pump =‘ Ave. monthly "Choking
Time period operability rain (inches) time" (hours)
(pumps/day)
July 1988-June 1989 5.89 3.47 148
July 1989-June 1990 6.75 3.94 114
July 1990-June 1991 8.28 3.05 40

1 The amount of time flow is held back from the plant at the headworks.

CSO screening
and chlorination
facilities can
significantly
improve bacterial
water quality

Two new facilities to provide treatment to combined sewage at major
overflow points have begun operations during the past two years. These
screening and chlorination facilities are located at Fox Point and
Commercial Point in southern Dorchester Bay. These facilities do not
remove either oxygen-demanding material (BOD) or toxic contaminants,
but have been effective in decreasing the load of sewage bacteria in the
water. Table 3-2 shows that fecal coliform counts in the water near Fox
Point were significantly lower after screening and disinfection began.
Although we do not yet have enough post-operational data to yield
statistically significant results, early indications are that counts near
the new Commercial Point facility have been substantially lowered since
operation began.

One of the most effective means of reducing the flow of pollutants into
our waters is one of the least glamorous: routine maintenance of the
sewerage infrastructure. Data collected near one of the single largest
sources of raw sewage to Boston Harbor, the combined sewer overflow at
the head of Fort Point Channel, illustrate this point (Figure 3-2). In the
winter of 1989-90, a one-million gallon-per-day dry-weather overflow

Is Boston Harbor Safe for Swimming and Boating?

Table 3-2. Fecal coliform counts in the water near new CSO treatment
facilities have decreased.

Area Facility status (dates) Average fecal coliform/100 ml
(95% confidence intervals)

Savin Hill Cove Preoperational (1989) 749 (403-1392)

(near Fox Point CSO) Operational (1990 and 1991) 79 (42-150)

Commercial Point Preoperational (1989 and 1990) 175 (93-327)

Operational (1991) 49 (16-147)

More aggressive
maintenance has
improved water

quality in the
inner harbor

Progress in
eliminating

improper sewer

connections to

storm drains is
vital in making

3-6

our beaches
swimmable

caused by a malfunctioning regulator in the pipe was discovered and
repaired. After this repair, routine fecal coliform counts in the Channel
dropped approximately two-fold.

Combined sewer overflows are not the only source of untreated sewage to
the harbor. Many pipes in the Boston area which are designed to carry .
only stormwater are contaminated by sewage, which is discharged into.
the harbor or rivers. Sometimes sewage can enter the stormwater pipes
from leaks in old, poorly maintained sewer pipes. Or, wastewater pipes
from homes and businesses are improperly connected directly to
stormwater pipes (rather than to sewers). Finding and repairing these
sources of contamination can have a dramatic effect on water quality.
For example, the Boston Water and Sewer Commission discovered that a
storm drain that discharges onto Constitution Beach was contaminated--
all the houses on one side of a street had their sewer pipes connected to
the storm drain! Repairing these illegal connections during 1990 has
contributed to a significant decrease in the number of postings at
Constitution Beach in 1990 and 1991, compared to 1989. Other illegal
connections have been corrected on the Charles and Neponset Rivers,
and BWSC continues with an active program to detect and correct these
problems.

Mathematical Model of Harbor Pollution, Based on New Data

One aid to understanding patterns of water pollution and their
relationship to environmental causes is to use a mathematical model to
calculate the fate a pollutant in the environment. The model uses
measured or estimated values such as the volume of sewage entering a
body of water, the concentration of a given pollutant in the sewage, the
rate of die-off or settling of a pollutant, together with the effects of the
shape of a body of water, water depth, and tidal circulation. Ona
computer, the model gives a picture of where the pollutant will go, how
long it will persist in the water, and how concentrated it will be. Using

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Is Boston Harbor Safe for Swimming and Boating?

2000 o-

1500 §

Geometric Mean Fecal Coliform Counts/100ml

1000 4 .
500 4
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Figure 3-2. Fecal coliform counts in Fort Point Channel. Average (geometric mean)
fecal coliform counts in Fort Point Channel have decreased by approximately haif
since a malfunctioning CSO regulator was repaired. Each bar represents the geometric
mean of approximately 20 samples. Some of the variation in counts is due to weather
conditions during the sampling period. There was substantial rainfall during the
way. October 1990 and August 1991 sampling periods, while June 1990 was
very dry.

Is Boston Harbor Safe for Swimming and Boating?

3-8

new (1990) measurements of CSO volumes and concentrations of
pollutants, researchers at Massachusetts Institute of Technology (MIT)
simulated water quality in the harbor after storms of different sizes.
Figure 3-3 shows the predicted effect of a rainstorm of a size which, on
average, occurs four times a year: "a 3-month storm": According to the
model, one day after the storm the swimming standard (200 colonies per
100 mL) will be exceeded only in Fort Point Channel, and near the
shoreline in Dorchester Bay. Two days after the storm, no areas of the
harbor violated standards (not shown).

Water Quality for Recreational Use Varies among Different Areas of the
Harbor

Swimmers in sewage-polluted water are in direct contact with the water
and are more at risk than boaters. Therefore water testing for public
health reasons is focused on beaches. The Metropolitan District
Commission (MDC) has jurisdiction over most beaches in Boston
Harbor, but some beaches in Quincy and Hingham are the responsibility
of the towns. Water samples are generally collected each week from
public beaches and analyzed for sewage-indicator bacteria: fecal
coliform and Enterococcus (see box on page 3-3). If the number of
indicator bacteria in the water is higher than state standards, the beach
is posted as unsafe for swimming, Although boating areas are not
routinely monitored or posted for public health reasons, bacterial water
quality data are collected in the inner and outer harbors by MWRA, by
the New England Aquarium, and by the Massachusetts Department of
Environmental Protection.

Inner Harbor

Although there are no bathing beaches in the inner harbor, this area is
popular for sailing and rowing small boats--activities which often mean
exposure to the water. Monitoring data collected by MWRA in 1989 and
1990 showed that the inner harbor is significantly affected by combined
sewer overflows. On average. if more than about an inch of rain fell over
three days, bacteria counts in the inner harbor exceeded swimming
standards for two to four days. During dry weather, most of the inner
harbor met swimming standards. Thus, except after heavy rainstorms,
especially in Fort Point Channel, water quality in the inner harbor is
good for recreational boating.

Northwest Harbor

Water quality in this part of the harbor varies greatly. In 1989 and 1990,
MWRA sampling showed that Carson Beach, Pleasure Bay and Northern
Dorchester Bay generally met water quality standards. Samples taken
near Calf Island in the outer harbor were all within swimming
standards. Southern Dorchester Bay, at the mouth of the Neponset River,
generally showed poorer water quality. This area is affected by the
Neponset River, contaminated storm drains, CSOs and possibly sludge.

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Is Boston Harbor Safe for Swimming and Boating?

Between 1 and 13 fecal coliform/100 ml
Between 14 and 199 fecal coliform/ 100 ml

Lesesssa Between 200 and 999 fecal coliform/100 ml

Figure 3-3. Effect of a ''3-month" storm on fecal coliform counts in Boston Harbor. A
mathematical model of fecal coliform counts in Boston Harbor shows the predicted levels of
bacteria in the water after a "3-month storm." The model uses new loading estimates from
1990. The figure shows counts in the harbor one day after the storm. Counts are predicted to
exceed the swimming standard in the Mystic, Charles, and Neponset Rivers, in portions of the
inner harbor, and in Dorchester Bay.

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Figure 3-4. Beach postings in Boston Harbor: 1989-1991. Bar graphs show the percent of water 5
samples which exceeded state water quality standards. Beaches shown are under the ot
jurisdiction of the MDC. Data for three years are shown: 1989-91. Much of the annual |

variation is due to differing rainfall patterns.

3-10 ; a)

Is Boston Harbor Safe for Swimming and Boating?

Samples collected at Dorchester Bay beaches in 1991 by MDC (Figure 3-4)
indicate a decrease in the number of postings at the two beaches in
southern Dorchester Bay: Tenean and Malibu. In the past, these beaches
have been affected by two major combined sewer outfalls, Fox Point and
Commercial Point. The decrease in postings at these areas can probably
be attributed to the operation of new disinfection facilities at these
outfalls.

Central Harbor

Water quality monitoring in the Quincy Bay area over the past two years
has shown generally rather poor quality and frequent postings at
Wollaston Beach, but good water quality in the offshore areas: even in
the Nut Island effluent outfalls. Results from sampling at Wollaston
Beach have implicated sewage-contaminated storm drains as a source of
sewage to the beach. When this problem is corrected, water quality at
Wollaston Beach should improve.

REPORT CARD
Is Boston Harbor Safe for Swimming and Boating?

1990 1991
Swimming D D+
t
Boating P net a B

311

7 OS™ Gt GE TEE

4. IS IT SAFE TO EAT FISH AND SHELLFISH?

Because of the
risk of sewage-
born infectious
disease, it is not
safe to eat
unpurified
shellfish from
Boston Harbor

Flounder, lobster and softshell clams in Boston Harbor are important
commercial and recreational food resources. Public concern about the
effect of pollution on seafood safety centers on two major issues: (1) the
risk of catching an infectious disease from shellfish harvested from
sewage-polluted water, and (2) the risk of consuming toxic chemicals
possibly present in shellfish or fish living in polluted waters.

Pathogen Contamination in Shellfish

By far, most seafood-borne illnesses are infectious diseases caused by
bacteria and viruses from sewage. Shellfish have a high potential for
spreading infectious disease for three reasons: (1) their habitat is in
coastal areas most subject to sewage pollution, (2) shellfish can filter and
concentrate disease-causing bacteria and viruses from the water, and (3)
shellfish are often eaten raw or lightly cooked. In the past, serious
diseases like typhoid fever and cholera were commonly spread in oysters
and clams. Because of this problem, the National Shellfish Sanitation
Program was developed to promote regulations for the microbiological
safety of shellfish and shellfish-growing areas. In the U.S., outbreaks of
typhoid fever and cholera from contaminated shellfish have virtually
been eliminated by stringent regulations that permit unrestricted and
recreational shellfishing only in relatively pristine waters.

In the U.S., the most common disease acquired by eating contaminated
shellfish is viral gastroenteritis, which is relatively mild, not usually
requiring medical treatment. Hepatitis A is a more serious, but rarer
viral disease sometimes spread by contaminated shellfish. The most
common shellfish-acquired bacterial diseases are caused by vibrios--
bacteria that live naturally in the marine environment and are not
necessarily associated with sewage contamination of shellfish.

In Boston Harbor productive clam beds, shown in Figure 4-1, cover about
4,700 acres. None of these beds are open for recreational clamming
because sewage indicator bacteria counts (see box on page 3-3) are too
high. About 2,900 acres of clam beds are restricted to harvest only by
“master diggers." These licensed diggers must take all clams harvested to
a depuration facility, where the shellfish are held in clean water for two
days to cleanse themselves of bacteria.

The Massachusetts Division of Marine Fisheries monitors shellfish-
growing waters as well as the clams themselves for bacteriological
safety. Some areas of Boston Harbor, especially in Quincy Bay and
Hingham Bay, are often conditionally opened, while other areas, like
Dorchester Bay, are virtually never opened (see Table 4-1).

4-1

Is it Safe to Eat Fish and Shellfish?

Inner Harbor

Outer Harbor

ved

Legend

SD Proivites
Conditionally

restricted
eae may .

Figure 4-1. Prohibited and restricted clam beds in Boston Harbor. There are many acres

of soft-shell clam beds in Boston Harbor, but none are open for unrestricted harvest.

4-2

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Is It Safe to Eat Fish and Shellfish?

Table 4-1, Restricted and prohibited productive clam beds in Boston
Harbor. Some productive clam beds in Boston Harbor are virtually
always closed, while other areas are frequently harvested.

Acres of

Harbor productive Percent of clam beds_classified as
area beds Open Restricted Prohibited
Inner Harbor 3 10) 1) 100
Outer Northwest

Winthrop 311 0 : 64 36

Islands 1,920 0 71 29

orother

Dorchester

Bay 519 0 18 &2
Central 551 0) 74 26
Southeast 1,381 0 58 42

Toxic Chemicals in Fish and Shelifish

Fish and shellfish can accumulate toxic chemicals by absorbing them
from the water, from direct contact with contaminated sediments, or
from their food. People who eat fish and shellfish contaminated with
toxic chemicals may suffer adverse health effects. The health risk
depends on the level of contamination, the toxicity of the chemicals and
the amount of contaminated seafood consumed.

The incidence of obvious disease in humans from eating chemically
contaminated seafood is very low, compared to outbreaks of infectious
diseases carried by fish and shellfish. Because of this low rate, the effects
on people of eating chemically contaminated seafood are not well
understood. Most knowledge of toxic effects from contaminated fish is
from epidemiological studies which compare disease rates in people who
have consumed seafood to disease rates in people who have not eaten the
seafood. There have been only a few cases in the world where
contaminated fish was clearly the source of a serious disease.

4-3

Is it Safe to Eat Fish and Shellfish?

4-4

FDA and EPA have used statistical risk-assessment
techniques to establish criteria for contaminants in food
which might cause health problems. These include:

(1) Risk-based limits. Concentration of contaminant
which may be high enough to cause health problems. Two
types of risk-based limits are:

a) Lifetime cancer risk level. This measure is used

for chemicals that have or may have a cancer-causing
effect. It is the level of a contaminant calculated to
produce a given number of excess cases of cancer
above the background rate in the population. Thus a
1-in-10,000 lifetime cancer risk level is the amount
of a chemical estimated to produce one additional
case of cancer per 10,000 people per lifetime of
exposure. (The background risk of cancer is 20 cases
per 100 people per lifetime.)

b) Reference dose. This measure is used to
characterize chemicals not thought to cause cancers,
but which might have other adverse health effects. It
is an estimate, based on animal testing, of the daily
amount that is unlikely to produce adverse health
effects during a lifetime.

(2) Regulatory limits. Concentration of contaminant which
is high enough for the FDA to remove foodstuff from
interstate commerce. These “action levels" are calculated
considering marketplace effects together with potential
health effects.

There have been no known outbreaks of diseases caused by toxic
chemicals in seafood from Boston Harbor nor have there been any
epidemiological studies of people who consume seafood from Boston
Harbor. Therefore, the only way to judge the risk from toxic
contaminants in Boston Harbor fish and shellfish is to compare
measured levels of contaminants to levels which are presumed to have
health effects. These levels are established by the Food and Drug
Administration (FDA) and the Environmental Protection Agency (EPA),
and are described in the box above.

This section discusses toxic chemicals found in three food species in the
harbor: winter flounder, lobster, and blue mussel. Flounder and lobster
live and feed on the bottom, and are thus potentially exposed to toxic
chemicals in the water, sediment and food organisms. The mussel lives
attached to rocks and pilings, and feeds by filtering particles from the

water, potentially accumulating chemicals associated with the particles.

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Is It Safe to Eat Fish and Shellfish?

Table 4-2 shows the average concentrations of selected contaminants in
winter flounder, lobster meat (not including the lobster "green organ" or
tomalley, which can have elevated concentrations of metals and organic .
pollutants) and blue mussels. Average values are an appropriate measure
because persons who regularly consume harbor seafood would experience
the average concentration over a long period of time.

Metals in Seafood Species in Boston Harbor

Figure 4-2 shows how the average concentrations of seven metals in
different food species compares to the FDA risk-based limit. The bars
show the ratio of the average metal concentrations found in each species
in the harbor to the FDA limit. All of the average metals concentrations

Table 4-2, Average concentrations of contaminants in edible tissues of
fish and shellfish from Boston Harbor [parts per million ( 1g/g wet
weight)]. Data are from NOAA 1991a.

Winter Lobster Mussels

Flounder Meat!
PAHs 0.0004 0.024 0.275
PCBs 0.337 0.118 0.149
DDT 0.065 0.005 0.016
Mercury 0.028 0.125 0.041
Cadmium 0.002 0.006 0.264
Lead 0.013 0.071 1.73
Copper 0.230 115 1.72
Chromium 0.022 0.043 0.249
Nickel ND 0.039 0.389
Zine ND 204 22.0

1 Data are for lobster meat only, not the tomalley (hepatopancreas)

4-5

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Figure 4-2. Average metals in Boston Harbor seafood compared to regulatory limits. The
average concentrations of toxic metals from three seafood species from Boston Harbor fall fa
below the risk-based regulatory limits for health effects. \

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4-6

New

Is It Safe to Eat Fish and Shellfish?

Toxic Chemicals in Edible Fish and Shellfish
Organic chemicals

DDT: insecticide used world-wide, banned in 1972.
Most "DDT" measured is actually the DDT breakdown
products DDD and DDE.

PAHs (polynuclear aromatic hydrocarbons): complex
organic chemicals, found in petroleum and in
products of combustion of fossil fuels. Many PAHs
are known carcinogens.

PCBs (polychlorinated biphenyls): a group of complex
chlorinated organic chemicals that are industrial in
origin. ,

Metals

All metals occur naturally in trace amounts, but
higher concentrations enter the environment through
discharge of sewage and industrial wastes. Because of
their toxicity, copper, mercury and lead are of concern.

were below the FDA limits (ratio was less than 1), and except for lead in
mussels, metals concentrations were 10- to 1,000- fold lower than the
limits. Lead in mussels approached the FDA risk-based limit.

Spatial Patterns of Metals in Mussels

Because mussels attach and grow in one spot, they are useful for
comparing conditions at different locations. The National Oceanic and
Atmospheric Administration (NOAA) has gathered "Mussel Watch" data
on concentrations of contaminants in mussel tissue at several different
locations within Boston Harbor. Only cadmium showed a statistically
significant spatial pattern, decreasing in levels from the inner harbor to
the southeast harbor.

To show how Boston Harbor compares to other urban harbors, Mussel
Watch data from the East Coast are presented in Figure 4-3. Boston
mussels showed higher levels than the average for all New England sites.
Mussels from Boston Harbor showed-higher levels of mercury and lead,
and lower levels of silver and copper than Chesapeake Bay and Delaware
Bay mussels. Boston Harbor and Hudson-Raritan Bay mussels had
generally similar metals levels.

4-7

pees eS OS frm Sa ED ST. OT Rs Em TT tm

Is It Safe to Eat Fish and Shellfish?

Organic Compounds in Flounder, Lobster, and Mussels from the Harbor

PAHs, PCBs, and DDT are three groups of organic compounds of concern
(see box). Table 4-2 shows average concentrations of these contaminants
in flounder, lobster meat and blue mussels. How these concentrations
compare to FDA action levels (for PCBs and DDT) or estimated action
levels (PAHs: see Appendix for explanation) is shown in Figure 4-4a. The
average concentrations of these organic chemicals were lower than the
action levels. Except for PAHs in blue mussel and PCBs in flounder,
concentrations of organic compounds were 10- to 1,000- fold lower than
action limits. Another way of looking at these data is to see how the
levels of contaminants translate to cancer risk. Figure 4-4b shows that
only PAHs in mussels and PCBs in flounder and mussels exceed the 1-in-
* 10,000 lifetime cancer risk level.

Spatial Patterns of Organic Pollutants in Mussels

Figure 4-5a shows how organic chemicals in mussels vary in different
parts of the harbor. The highest PAHs are found near Deer Island,
intermediate levels in Dorchester Bay, and the lowest levels in the outer
harbor islands (Brewsters) and in Hingham Bay.

How Boston Harbor compares to other Mussel Watch sites on the East
coast is presented in Figure 4-5b. Boston Harbor mussels have organic
contaminant levels that are higher than the mean of New England sites,
but intermediate among other urban harbors.

Patterns of Organic Pollutants in Mussels over Time

NOAA found that the only toxic contaminant that showed a change over
time was the pesticide DDT, which has been declining over the last few
decades. DDT was banned from production and use in 1972.

Summary of Chemical Contamination in Boston Harbor Fish and
Shellfish

Overall, available information indicates that Boston Harbor fish and
shellfish contain levels of chemicals that are higher than cleaner
offshore areas but comparable to those found in other urban areas.
Average concentrations are below action levels.

For organic chemicals the grade of C- results from an average of levels of
PCBs, PAHs and DDT from mussels, the species that has had the highest
levels of organic contamination. Concentrations of PCBs and PAHs in
mussels were relatively high, exceeding cancer risk levels of 1 in 10,000,
while concentrations of DDT were relatively low. For metals, the grade
of B- is a reflection of the average metals levels in all three species, which
were well below risk-based limits.

4-10

Ratio = 1 Concentration = Regulatory Limit

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.001
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Lobster meat
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B.

1-in-10,000 risk level

J 1-in-100,000 risk level

DDT PAH

Figure 4-4. Organic chemicals in seafood from Boston Harbor. A. Average concentrations of
organic chemicals in seafood from Boston Harbor (excluding lobster tomalley) were less than
the regulatory limits. B. The estimated increased risk of cancer from consumption of seafood is
shown, assuming ingestion of 6.5 grams of fish per day. PAHs and PCBs in blue mussels
exceeded the 1-in-10,000 lifetime risk level, as did PCBs in flounder.

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3 15 4 Boston Harbor
E 1 New England average
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Figure 4-5. Organic chemicals levels in mussels within Boston Harbor and compared to
other urban estuaries. A. Average DDT, PAHs and PCBs measured in mussels in different
areas of Boston Harbor, 1990, There is no consistent geographic trend among the three
organic chemicals measured in mussels from different areas of Boston Harbor, except that
outer harbor islands and the southeast harbor show lower levels than near Deer Island and
in Dorchester Bay (data from Battelle, 1990). B. Comparison of organic chemical levels in
mussels from Boston Harbor and other east coast estuaries. Levels of toxic organic .

- chemicals in Boston Harbor mussels are similar to other urban estuaries along the east

sooo The reference site is an uncontaminated site off the Maine coast (data from Battelle,
1990).

4-11

Is it Safe to Eat Fish and Shellfish?

4-12

Report Card:

Although the grades for safety of fish and shellfish have changed this
year, the changes are due to the use of more refined and well-defined
eriteria for determining grades, and do not indicate an improvement

since 1990.

REPORT CARD

“1990
Shellfish: Pathogens D-

Fish/Shelifish: Organic
Contamination C-

Fish/Shellfish: Metal
Contamination B-

Is it Safe to Eat Fish and Shellfish?

1991

Lesetenenes) Sere ad

Nemet

4
sa

§. ARE FISH AND OTHER MARINE RESOURCES
BEING PROTECTED?

The well-being of
marine animals
is affected by
conditions in the
water and
sediments

Concern about whether marine resources are being protected from
pollution differs from concern about whether we will be able to safely eat
fish and shellfish. This section considers the well-being of the resources
themselves. We focus on fish and seafloor (benthic) animals because
these groups contain commercially valuable species and because data
about the health of these animals are available. Members of these groups
show effects that can be related to contamination of the environment.

The health of marine animals is affected by conditions in the water and
in the sediments. Thus, this section focuses not only on the condition of
the animals themselves, but the pollution levels in the waters and
sediments where they live. The quality of the harbor's waters is
discussed first, then sediment conditions, and finally indications of the
health of fish and benthic species.

Water Quality
Dissolved Oxygen

While terrestrial animals, as well as seabirds and marine mammals can
breathe oxygen from the air, marine organisms use oxygen dissolved in
seawater. Depletion of some (hypoxia) or all (anoxia) of the oxygen in the
water or in sediments can cause loss of habitat, stress, or death. For this
section, hypoxia is defined as occurring when the concentration of
dissolved oxygen is less than 5 milligrams/liter (mg/L), the
Massachusetts standard for "fishable, swimmable" (Class SB) waters.

Sewage discharged into the marine environment will decay, which uses
up oxygen dissolved in the water. Dissolved oxygen problems aggravated
by sewage discharges are likely to be most severe in the summer. There
are two reasons for this condition: (1) oxygen is chemically less soluble
in warmer water, so oxygen levels are lower in warmer waters; and (2)
the metabolic rates of marine organisms increase in warmer water,
which means they use oxygen more quickly.

MWRA routinely measures dissolved oxygen (DO) in the inner harbor,
the central harbor, the northwest harbor, and in the harbor's tributary
rivers. The New England Aquarium also measures dissolved oxygen at
sites throughout Boston Harbor. These studies give a good indication of
summertime DO levels at mid-day, when the measurements are made.
However, aquatic plants, both large (seaweeds) and microscopic
(phytoplankton) produce oxygen in daylight (increasing DO), and
consume oxygen (decreasing DO) at night. Therefore, the available data

5-1

Northwest Harbor

Inner Harbor

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Dissolved Oxygen, mg/L .

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Dissolved Oxygen, mg/L

Figuré 5-1. Histograms of dissolved oxygen measurements in Boston Harbor. Distrib

osm

ution of

tributaries of Boston Harbor. The dashed line at 5.0 mg/L indicates the Massachusetts DO

standard for Class SB waters. Data from MWRA (1991a).

summer surface and near-bottom dissolved oxygen concentrations in the regions and major

5-2

Most areas of the
harbor have
sufficient
amounts of
oxygen dissolved
in the water for
the health of fish
and other marine
animals

Are Marine Resources Protected?

may underestimate the true extent of low oxygen levels in the harbor.
Future monitoring by MWRA will include early morning measurements
designed to address this question. Figure 5-1 shows the dissolved oxygen
measurements in different areas of the harbor.

¢ Inner harbor: Bottom waters in the inner harbor frequently violate
the DO standard of 5.0 mg/L, with occasional measurements below 2
mg/L. Low oxygen conditions are much rarer in surface waters, and
tend to occur in restricted channels with high CSO input, such as Fort
Point Channel and the Reserved Channel.

¢ Northwest harbor: Dissolved oxygen in Dorchester Bay and other
parts of the northwest harbor measured by the MWRA monitoring
program are nearly always above the 5 mg/L standard, with only two
measurements between 4 and 5 mg/L at the mouth of the Neponset
River. Similarly, no depressed oxygen levels have been noted in the
northwest harbor by the Aquarium's monitoring program.

* Central and southeast harbors: As discussed in Section 2, most of
Quincy and Hingham Bays are well flushed with water from offshore,
and the sewage effluent from the Nut Island treatment plant seems to
disperse relatively quickly. DO concentrations are good in this area.

* Charles River: A large amount of seawater infiltrates through the
locks in the Charles River Dam. Since salt water is heavier than fresh
water, this causes a pool of saline (salty) water to form under the fresh
water. The saline water is cut off from the air, and does not mix well
with the freshwater flow of the river. All of the dissolved oxygen is
consumed, so that there is often no DO in summer in the bottom waters
of the Charles River Basin. Surface DO levels in the Charles River are
occasionally near or below the state standard, usually following
storms that cause CSO discharges. :

* Mystic River: The freshwater part of the Mystic River generally shows
satisfactory oxygen levels. However, low concentrations of dissolved
oxygen are common in the sluggish, heavily polluted Alewife Brook,
which feeds into the Mystic.

Toxic Contaminants in the Water

The EPA has developed water quality criteria designed to protect aquatic
organisms from the adverse effects of environmental contaminants.
Massachusetts has adopted the EPA's criteria as part of the State's Water
Quality Standards. As described in last year's State of the Harbor report,
Boston Harbor generally meets the water quality criteria for toxic
contaminants, and there is some evidence that metal concentrations in
harbor waters are decreasing.

5-3

Are Marine Resources Protected?

The inner harbor
has more toxic
chemicals in the

water than the

outer harbor near

the sewage

treatment plants

Toxic metals in

the waters of

Boston Harbor

have been
decreasing

Bioaccumulation

Clams and mussels, which filter food particles out of the water, often
concentrate toxic metal and organic compounds in their tissues to levels
well above those found in the water itself. This process is called
bioaccumulation. Studies of bioaccumulation can be used as an
indication of the potential effects of contaminants present in the water
at concentrations so low that they are difficult to measure. The level of
bioaccumulation is, therefore, useful as a measure of water quality.

Bioaccumulation studies with mussels showed that copper and PAHs
accumulated in mussels near Deer Island and the inner harbor, near the
Aquarium, to a greater level than in mussels at a relatively clean
reference site near Gloucester. This 1991 study showed that mussels at
the inner harbor site accumulated more toxic chemicals from the water
than did mussels near the Deer Island effluent and sludge outfalls. The
inner harbor location was distant from the MWRA effluent discharges
but potentially affected by CSOs, runoff from industrial and oil storage
facilities on the Mystic and Chelsea Rivers, shipping activities, and
contaminated sediments. Both sites showed less bioaccumulation of
toxic chemicals than in a similar study carried out in 1987.

The 1990 State of the Harbor report discussed recent decreases in the
amount of toxic metals in MWRA effluent discharges. There has been a
4-fold decrease in metals discharged to the harbor from 1981 to 1991.
The results of the 1991 bioaccumulation study, along with other studies
previously discussed in the 1990 State of the Harbor report, suggest that
the improvements in MWRA discharges are being reflected in
improvements in water quality.

Sediments
Dissolved Oxygen

Just as marine aquatic organisms need oxygen, so do animals living in
sediments. Marine sediments typically have an oxygenated layer (often
grayish-looking) overlaying a black layer with no dissolved oxygen. The
organisms living in sediments create a constant demand for oxygen as
they respire. This oxygen can be replaced by the slow diffusion of oxygen
from the water above the sea floor into the sediments. If the amount of
organic matter decomposed by microorganisms in the sediments is too
high, for example from too much sewage, microorganisms use oxygen
faster than it can be replaced. When this occurs, the oxygenated layer
becomes very shallow. The zone that separates oxygenated

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Are Marine Resources Protected?

Rois

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sediments (the upper layer) from the sediments lacking dissolved oxygen
(the bottom layer) is called the "redox potential discontinuity" (RPD). As
the level of oxygen in sediments decreases, the RPD becomes very
shallow. Under these conditions, animals that cannot tolerate depressed
oxygen levels disappear from the community. This situation can leave
dense communities of only the few species that can thrive in a degraded
environment. If sewage deposition increases further, the RPD moves
near or to the sediment surface, and only a small number of individuals
from one or two species can tolerate such conditions. Extreme amounts
of organic deposition to the sediments can result in areas of the seafloor
being unable to support any benthic animals at all. The depth of the RPD
is a useful indicator of sediment quality: a shallow RPD indicates that
the sediments are likely to stress the organisms living in them. The
average RPD in other open coastal systems in New England is greater
than 3 cm (2.5 cm =1 in).

Dissolved oxygen Inthe summers of 1989 and 1990, MWRA carried out surveys of sediment
concentrations conditions in Boston Harbor using a camera that photographs a cross
are low in section of the top 20 cm (20 cm = approximately 8 in) of the seafloor (see
sediments in the inset on Figure 5-2), Photographs of several cross sections at every
inner harbor and _ station allowed us to determine the average depth of oxygen penetration
northwest harbor into the sediments, the RPD, at over 100 stations within the harbor
during the 1989 and 1990 surveys (Figure 5-2).

eee

¢ Inner and northwest harbors: The average RPDs in the inner and
northwest harbor are quite low, with most stations having an RPD of 1
cm or less, with many stations near Deer Island and in Winthrop Bay
having no oxidized layer in the sediments. Some sandy areas near the
airport have RPDs greater than 2.5 cm.

wed

¢ Central harbor: Shallow, muddy areas of Quincy Bay near Squantum =|
and Wollaston Beach also have shallow RPDs, ranging from 1.8 cm to df
less than 0.3 cm. Deeper parts of Quincy Bay, which are well flushed by
the strong tides, show much deeper RPDs, as deep as 3.6 cm. iT
Sediment i
oxygenation in» Southeast harbor: Although there are some muddy areas where the oF
the central and RPD is less than 2 cm, much of Hingham and Hull Bays have the
southeast parts of deepest oxygen penetration into the sediments measured in our
the harbor is surveys, as deep as 6.3 cm.
generally
satisfactory

Toxic Contamination in Sediments

eres ly
pereny
Ripe

It has been recognized for some time that contaminants accumulate in

sediments, but most scientists considered this process a means of “my
removing toxic contaminants from the water and keeping them in place. ad
It has now become clear that toxic contaminants in sediments can pose a

threat to aquatic and human health, and can be transported on

resuspended sediment particles to other areas and released to the 8

£
ana

overlying water. Contaminants in sediments are important, but it is
more difficult to assess the condition of sediments than the condition of
water. No numerical standards have been established for sediment
contaminants, although EPA and several states are currently developing
quality criteria for sediment.

5-6 fe)

Metals

be
vo
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8 3
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T ¥ T T
° ° ° ° °
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Organic Chemicals

Total PCBs
ea Total PAHs

bo)

ERECEMEE
eearececarece
Wetetatetctatete

= 2.0.0.6.8:
KKK KO

100000

10000 q

uoThG red spied ‘suotzeIzUI0N0D

All

Northwest Central Southeast

Inner

Region

region. The

The data are from NOAA (19912).

Comparison of the

diments of Boston Harbor by

concentrations of selected toxic chemicals in the se
error bars indicate the average plus 1 standard deviation.

Patterns of sediment contamination in the harbor.

Figure 5-3.

5-7

Are Marine Resources Protected?

The inner harbor
generally has the
worst sediment
contamination in
Boston Harbor

Levels of toxic
contaminants in
Boston Harbor
sediments are
similar to other
urban estuaries

Geographic Patterns of Sediment Contamination in the Harbor

Recent studies have summarized historical data on sediment
contamination in Boston Harbor. These studies indicate that metals and
organic contaminants are widespread in Boston Harbor sediments, and
that the concentrations in the harbor are higher than naturally
occurring concentrations at uncontaminated reference locations.

Within the harbor, the pattern of sediment contamination is similar for
most chemicals. The highest concentrations are typically found in
sediments from the inner harbor, with progressively lower levels in the
northwest harbor, the central harbor, and the southeast harbor (Figure
5-3). In the inner harbor, for example, the concentrations of PAHs in
sediments are five to ten times higher than concentrations in sediments
from other regions of the harbor. Within this general trend, however,
sediment concentrations of toxic chemicals show a high degree of
variation within the individual regions. For example, in a recent study
of sediments in Dorchester Bay, concentrations of PAHs varied by a
factor of over 100, from 0.55 parts per million (ppm) to 66 ppm. This
variation may be caused by the multiple sources that contribute to
sediment contamination. Sources include point-source discharges from
local CSOs and stormdrains, as well as more distant sources like sewage
effluent and past sludge discharges.

Comparison of Boston Harbor Sediments With Those in Other Areas
Although the results of the NOAA National Status and Trends Program

shows that concentrations of most contaminants in Boston Harbor
sediments are higher than those found at New England reference sites,

’ the results also show that sediment concentrations are similar to other

urban harbors (Figure 5-4).

Biological effects of toxic chemicals in sediments: While toxic chemicals
are elevated in Boston Harbor compared to New England reference areas,
that does not necessarily imply that the sediments throughout the

- harbor are toxic to marine organisms. High concentrations of hydrogen

sulfide (the compound that gives rotten eggs their characteristic smell) in
sediments have recently been shown to bind metals so strongly to the
sediment grains that often little or no metals toxicity exists, even in
highly contaminated sediments. Similarly, bulk organic carbon in
sediments strongly binds organic contaminants like PCBs and DDT,
lessening their toxicity.

One recent University of Massachusetts/Boston study found that the
effects of sediment metal concentrations on the types and numbers of sea
floor animals in Dorchester Bay was slightly more important than the
effects of oxygen-consuming organic matter in the sediments.

anneal

a) a

tees és aay

i]
rd

eae

pound

wey ce ee
“he jana Nett

tad

1000 ~

Metals

100 4

10 4

Concentrations, mg/kg dry weight

100000

Organic Chemicals

10000 4
1000 .J
100 4

10 4

Concentrations, nanograms/gram

WH Boston

EZ Delaware Bay

PAHS PCBs DDT

Harbor [7] New England Mean Eg Hudson /Raritan

Za Chesapeake Bay

Figure 5-4. Comparison of sediment contamination to other areas. Comparison of the
concentrations of selected toxic chemicals between Boston Harbor and other areas. The data
are the averages of the NOAA Status and Trends sediment monitoring, 1984-1989.

5-9

Are Marine Resources Protected?

5-10

Some scientists have suggested that the sediment concentrations of some
contaminants, particularly metals, may be decreasing in the harbor.
These claims are based on data from sediment cores in which ;
contaminants were measured at different depths. One study indicated
that there has been a significant reduction in the input of copper and
cadmium (and possibly other metals) to the sediments of Boston Harbor
in recent years. This observation may be related to the recent reduction
in toxic chemical concentrations in MWRA's sewage effluent and sludge.
The trends noted in these sediment cores were subtle: at the rate
observed, it would take a century to reduce contaminant concentrations
by half. However, there will be dramatic decreases in loadings of toxic
chemicals to the harbor because sludge is no longer being discharged, and
the new treatment plants will remove toxic chemicals more effectively.
The decrease in toxic loadings should speed the natural cleansing of
sediments.

Summary of Habitat Conditions in Boston Harbor

The habitat in which the marine resources of the harbor live is stressed
in several ways. While conditions in the harbor's waters usually meet
water quality standards for most chemicals, there are regions in which
dissolved oxygen concentrations are likely to be at least intermittently
stressful. The shallow oxygenated zones in the harbor's sediments are
also likely to stress the organisms living within them, and there may be
some effect of toxic chemicals in the sediments.

Living Resources
Winter Flounder (Pseudopleuronectes americanus)

Boston Harbor supports a large sportfishery. Migratory striped bass and
bluefish spend the summer and fall months in the harbor following
schools of mackerel and menhaden. Historically, the mainstay of the
sportfishing industry in Boston has been the winter flounder, but
declining numbers (a New England-wide phenomenon) and a public
perception that the flounder from the harbor are contaminated has led to
a substantial decrease in the number of people fishing for flounder.

Assessments of the health and condition of winter flounder in Boston
Harbor are conflicting. On the one hand, although the actual stock of
winter flounder has decreased, the population in the harbor appears to be
capable of sustaining itself. On the other hand, a number of
abnormalities, such as fin rot and organ lesions (injuries), are found on
fish from Boston Harbor. These abnormalities can be strongly linked to
a degraded environment.

ac, oo

elo Eg

ore

Are Marine Resources Protected?

"Fish Day," sponsored by the New England Aquarium in 1989, was

i described in detail in the 1990 State of Boston Harbor report. The results
~ of the "Fish Day" studies indicate that flounder from Deer Island Flats in
., : the northwest harbor typically have a higher incidence of fin rot, liver
of lesions, and a host of other abnormalities than do fish from other parts
y of the harbor. The New England Aquarium and MWRA will be
sponsoring “Fish Day II" in the spring of 1992, to investigate how the
health of the flounder has changed from 1989.

A new study conducted by researchers from the Woods Hole
Oceanographic Institution suggests that the prevalence of liver lesions
oA has declined in recent years (Figure 5-5). The data gathered in the next
, "Fish Day" will allow researchers to see if this trend is reflected in other
indicators of the flounder population's health.

Lobster (Homarus americanus)

Boston Harbor is a suitable habitat for lobster spawning, development
and growth. Lobsters can live in different habitats in the harbor,
including mud bottoms, sands, gravel, and rock outcrops. In the spring,
summer, and fall, the harbor is heavily fished for lobster. The majority
: of lobsters landed in Boston during these months comes directly from
oa Marine animals _ the harbor. In winter the lobsters migrate offshore to warmer waters.
a in the harbor
a show signs of | Throughout much of the harbor, lobsters are found in mud burrows.
{ physiological They can tolerate low concentrations of dissolved oxygen, and so are
i] stress, but they _ generally not impacted by short-term conditions of low oxygen. The
, have abundant Massachusetts Division of Marine Fisheries reports that lobsters from
populations Boston Harbor generally do not exhibit symptoms of pollution (e.g.,
black-gill disease) observed in other areas. Histopathological evaluation
of lobsters from Quincy Bay indicated that they were generally healthy
and did not exhibit symptoms of disease.

Soft-shell Clams (Mya arenaria)

Although there are restrictions on harvesting soft-shell clams due to
bacterial contamination caused by sewage pollution, Boston Harbor is
productive: about 20,000 bushels are harvested annually. Thus, the clam
population within Boston Harbor is sustaining itself despite
contamination in the sediments where they live. The few studies that
have looked for evidence of diseases in clams have found more
abnormalities in clams from the harbor compared to other areas.

red Seafloor (Benthic) Communities

Animals living on or in the sediments at the bottom of a body of water
are called the benthic community. A marine benthic community can
include lobsters, clams, and crabs, as well as worms and small
crustaceans that are a food source for bottom-feeding fish and lobster.

5-11

Liver Neoplasia (cancers)

SSBOSTP YIM YSH JO FUIIIOg

1987 1988 1989 1990 1991

1984

Liver Vacuolation

PI eee ey
EAC Ce
NNN NNN ON
PARE EE AEE El
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sos" s Curie area ee

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NNN NN NNN SNS SUNN NUNS
FEAT AEE REED RE EEE DE
NNN NNN NANOS SS NSU RRO AU SUNS
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PRE RE AERC AERE RE DEDEDE TE AACR DE TE TE
NN SN NN NUNN A ANNA SOS AUN AUN NAS
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faraeaed

PRCA REIT DE DEDEDE TERE DEDE TE TED DED TE TT Te
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1987 1988 1989 1990 1991

1984

Year

B. Liver vacuolation, a

condition in which abnormal fluid-filled cells appear and increase in abundance within liver

tissue. This condition is commonly associated with the early stages of systemic stress.

|
G
B
3
&
2
4
oe
E
&

iy
8
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a
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6
E
8
&
3
~~
i=]
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:)
~
5
5)
.)
B)
a

Island Flats with two types of liver disease, including data from 1984
1985), and 1987-1991 (Moore et al. 1991) A. Liver neoplasia, or cancer.

Figure 5-5. Declining liver lesions in winter flounder.

5-12

ep
1

Sewage effects on
rocky-bottom
communities
are obvious

only within

two or three
miles of the
sludge discharge

Are Marine Resources Protected?

Benthic communities have long been monitored as indicators of
environmental health. Because most of these animals are sedentary,
and cannot leave a polluted area, they are more susceptible to
contamination than are more mobile animals. Pollution can change the
kinds of animals found at a particular site (community composition),
the number of different species present (diversity), and the total number
of individuals of all species (abundance or density).

Many factors besides pollution influence what types of benthic
communities develop in a given area. One of the most important
determinants of the benthic community is bottom type: mud, sand, or
rocky bottom.

Hard Bottom

Hard or rocky bottoms are usually found where currents or waves
prevent the accumulation of particles (sediment). The hard-bottom
community in and around Boston Harbor consists of organisms that
attach to rocks; for example sea anemones, tunicates (sea squirts),
mussels, and seaweeds. Other members of the hard bottom community
are sea urchins, whelks, and crabs that live with or eat the attached
plants and animals. The main impacts of sewage pollution seem to be
from sewage solids coating the rocks with a thin layer of temporary
sediment. This layer may prevent juvenile organisms from attaching to
the rocks in a normal manner, or it may smother them or have a toxic
effect if the organisms do settle on the rocks.

Researchers from Northeastern University's Marine Science Center on
Nahant have carried out a multi-year study of the effects of MWRA
sewage discharges on the rocky-bettom communities from Lovell Island,
which is near the former sludge discharge from the Nut Island treatment
plant, to a relatively pristine area off of Nahant (Figure 5-6). They found
that sewage tracers (copper and Clostridium perfringens spores) in the
fine sediment on the rocks decreased dramatically with distance from
the harbor. Near Lovell Island where sediment on the rocks was
sewage-derived, the rocky bottom community was sparse and dominated
by worm tubes. Near Nahant, there was less mud-covered rock.and a
more natural, diverse community (Figure 5-6).

Soft Bottom

Mud bottoms are found where water movement is slow enough for fine
sediments to settle, and sandy bottoms where current and wave strength
prevent permanent deposition of fine particles, but are not strong enough
to wash the sand away. The assemblages of organisms that inhabit sand
and mud bottoms are called the soft-bottom benthic community. Muddy-
bottomed areas are natural centers for the accumulation of fine sewage
particles and the toxic chemicals associated with them.

5-13

i@Deer Is- and Nut Is-
Qutfalis

4
200 1,000,000 = /oo -
Be (Copper ~ 5 — EE Tube complex
2 2 3 = Sea urchins
s = 0G - Clostridium x: 3 o>
2 8 yg J
2 i s - 3
c 3 2
z . 100,000 £ <
g § z
2 & F ow
z g 8 L 2
z E 8 404 ;
5 F 10.000 5 2 !
. 3 3 : Ly
3 3 = 20 :
a ao} 5 7 i
Ey S) z '
° 8 :
= a
1,000 5 ° (es) : °
&
= 1 2 3 4 5 6
Station Shudge Deer Broad Nahant
Discharge Island Sound

Figure 5-6. Rocky bottom benthic communities and sewage tracers from Lovell Island to
Nahant. A. Map of the rocky bottom sites sampled from Lovell Island to Nahant. Station 1 is
approximately 1 km from the old sludge discharge from the Nut Island plant, while Station 6
is almost 9 km from the nearest MWRA discharge. 8B. Concentrations of copper and counts of
the sewage indicator bacteria Clostridium perfringens at the sampling sites. C. Two
measurements of the health of the bottom community at the sites sampled. "Tube Complex" is
the sum of the percent cover of mud covered rock and the tube worms that live in the mud.
“Urchins" represents the abundance of sea urchins. While the data show high variation, there
is a trend showing stressed conditions near the harbor as opposed to normal conditions near
Nahant. Data from Sebens and Witman (1990).

5-14

Sea urchin abundance / 0.05 sq. meter

Seed | Anta

bog
Seanad

ane

ros Loy ,
al en? [onary]

3
}

}

Populations of
seafloor
animals in the
harbor are
affected by
low oxygen
levels in the
sediments

Are Marine Resources Protected?

The effects of sewage pollution and other organic-rich discharges (such
as paper-mill effluent) on soft-bottom communities are well understood.

Low levels of sewage act as an additional food source, stimulating growth
and resulting in increased abundance and diversity of the natural
community. Greater amounts of sewage can outstrip the capacity of the
soft-bottom community to use it. This excess matter leads to a buildup of
oxygen-consuming organic matter in the sediments, and the depth of the
oxygenated layer decreases. As sediment conditions deteriorate, more
and more species disappear from the community. Intermediate levels of
sewage input can result in densé communities of a small number of
tolerant species. High levels of sewage result in communities with only a
few scattered individuals of one or two pollution-tolerant species.
Extreme pollution can result in areas of the bottom having no animals at
all. Direct effects of toxic chemicals upon soft-bottom communities are
noted only infrequently; most of the degradation seen is attributable to
this enrichment (excess nutrients) effect.

Evaluation

To evaluate the conditions of benthic communities in Boston Harbor, we
have compiled data from multiple sources, including surveys conducted
by the MDC in support of the secondary treatment waiver application,
studies conducted by the U.S. Army Corps of Engineers in the inner
harbor, and recent surveys carried out by MWRA.

Figure 5-7 shows a simplified representation of the distribution of
benthic communities within the harbor.

Inner Harbor

Just as the inner harbor contains some of the most toxic-contaminated
sediments in Boston Harbor, it also contains the most degraded benthic
communities. There are only a very few species present, and some large
areas seem to have no benthic organisms living there during the late
summer and fall. Sediments from the inner harbor showed significant
toxicity to the marine amphipod Ampelisca, a shrimp-like organism
commonly used in sediment-toxicity studies. Ampelisca is abundant in
the other parts of the harbor.

Northwest Harbor

The northwest harbor is a complex area. Areas highly degraded by
sewage effluent and sludge are found in Winthrop Bay, on Deer Island
Flats, and the adjacent anchorage area.

The bottom near the northwestern shore of Long Island appears to be
impacted by sludge from the Nut Island treatment plant. Recent
sampling by MWRA indicates that much of this area is somewhat
degraded, with high densities of shrimp-like amphipods that feed on
recently deposited sediments. These types of communities are often
associated with moderate levels of enrichment impact.

5-15

LEGEND

C_] No Data
Slightly Impacted

Impacted

Degraded

Figure 5-7. Benthic communities in the harbor. A simplified representation of the
distribution of soft-bottom communities in Boston Harbor, summarizing the data and
conclusions from various studies: Blake et al. (1989), Gallagher and Grassle (1990), Hubbard
and Bellmer (1989), Michael and Menzie (1991), and SAIC (1990). The borders of the zones are
approximate. "Slightly impacted" denotes areas of bottom that, while not pristine, have
communities similar to those from un-impacted coastal New England estuaries. “Impacted!
areas have communities that are adversely affected by pollution. "Degraded" areas have
extremely polluted communities.

5-16

are

of
ene

aed

Are Marine Resources Protected?

Dorchester Bay is relatively distant from most large sources of sewage
contamination, but the University of Massachusetts/Boston study
mentioned above suggests that much of the bay may be affected by sludge
from Nut Island. Small areas of Dorchester Bay, for example Savin Hill
Cove, are highly degraded.

Central and Southeast Harbors

Most of the benthic studies in the central harbor have been done in the
well-flushed outer portions of Quincy Bay. Many of these samples, as
well as the few samples available from the southeast harbor, reveal a
diverse, abundant benthic community very similar to unimpacted
estuaries in New England. However, sediment camera images from
inshore areas in these regions, nearer to Wollaston Beach and in the
mouth of the Fore River, reveal extensive areas with shallow oxygen
penetration in the sediments. Computer modelling and the results of
sampling for spores of the sewage tracer bacterium Clostridium
perfringens indicate that these near-shore areas are somewhat impacted
by sewage discharges from the Nut Island treatment plant, but there are
no benthic samples to describe those communities.

The interplay of sediment types, water flow, and sewage impact creates a
complex mosaic of benthic communities within the harbor. Within any
given subregion (except possibly the inner harbor, which may be
uniformly bad) there is a range of impact from multiple near and
far-field sources, Despite this variation, a general trend is seen of
extreme pollution impacts upon benthic communities in the inner
harbor, with seriously degraded conditions prevailing in the northwest
harbor. The southern portions of the harbor, perhaps due to greater
flushing with Massachusetts Bay, in general appear to contain
"healthier" benthic communities than the northern harbor.

REPORT CARD
Are Fish and Other Marine Resources Being
Protected?
1990 1991

Sediment Contamination D- D-
Water Quality: Oxygen Cc c
Water Quality: Toxic .

Contamination B- B-
Fish Disease D- D-
Seafloor Animals D- D

ces a

pron
k

oi ny

roy tos tre
Beeld u a

Som TR FT ST

ey
|

6. IS BOSTON HARBOR AESTHETICALLY
PLEASING?

Aesthetic quality
is an integral part
of the
environmental
health of the
harbor

Since
installation of
scum-removal

equipment in
1988, the MWRA
has removed
23,000 tons of
scum and debris
from the
wastewater

Turbidity within
the sludge plurne
was as high as 90%

Although chemical and microbiological contaminants are important in
assessing the environmental health of the harbor, the public's
perception of environmental quality is often based on more conspicuous
signs of contamination. Offensive odors and unsightly floating debris
instinctively suggest pollution. The presence of scum, effluent, and
sludge from sewage treatment plants, as well as turbid water and marine
debris all degrade aesthetic quality. These conditions, as they relate to
aesthetics, were discussed in the 1990 State of the Harbor report. New
information and data related to these topics are presented below.

Scum and Sewage-Related Floating Debris

Scum is material in wastewater that floats. It is made up of oil, grease,
and plastic debris. Before 1988, nearly 10,000 gallons (33 tons) of scum
were pumped into the harbor each day. Since 1988, scum has been
removed from wastewater as part of the treatment process at the Deer
Island and Nut Island facilities. New screens and skimmers have
removed approximately 12,000 tons per year of scum and floating debris
that would formerly have been discharged directly into the harbor. The
scum has been mixed with a chemical stabilizer and landfilled at Deer
Island, but now will be processed with the sludge at the Quincy sludge
processing facility.

Effluent and Sludge

Until December, 1991, sludge was discharged from both Deer and Nut
Island on every outgoing tide in a black and offensive-smelling plume.

Although effluent from the sewage treatment facilities is still being
discharged into Boston Harbor, the volume of waste materials decreased
significantly (see Section 7) when discharge of sludge ceased. Sludge is
now transported to a processing plant in Quincy where it is made into
fertilizer. Discharge of treated effluent into the harbor will continue
until 1995 when the new outfall, extending into Massachusetts Bay, is
completed. Then, the unsightly plumes and odors that result from
discharging sewage wastes into Boston Harbor will be eliminated.

Turbidity

Measurements made in the sludge plumes from the Nut Island treatment
facility indicated that water turbidity--a measurement of lack of
clarity--was very high, ranging between 80 and 90%. Turbidity of the
harbor water normally is highly variable, but measurements showed

Aesthetics

Water clarity has
improved, now
that sludge is
treated

onshore

Dangerous and
unsightly
floatable

debris has many
sources

Debris collected
at Boston Harbor
beaches in

1990 was 30%
lower than the
amount collected
in 1989

In 1990, more
tampon
applicators were
removed from the
shores of
Massachusetts
than from any
other coastal state

6-2

that it generally did not exceed 50%. One hundred percent turbidity
means suspended particles are totally blocking light in the water. Now
that sludge discharges have stopped, this source of turbidity is gone.
However, particulates are still contributed by effluent, and during
periods of heavy rain and increased river flow, some particulate matter
will still be transported into the harbor and will temporarily decrease
water clarity.

Marine Debris

Marine debris is made up of a wide assortment of plastic, metal, paper,
glass, and wood waste materials. There are many sources of these wastes,
including commercial and recreational vessels, sewage treatment plants,
CSOs, beach and street litter, and deteriorating piers and waterside
structures, Either floating on water or littering the shores, marine
debris degrades aesthetics of the environment, endangers wildlife,
affects commercial and recreational activities, and poses threats to
human safety.

During the 1990 Coastweeks beach cleanup, coordinated by the
Massachusetts Office of Coastal Zone Management, almost 60,000 Ibs. of
debris were removed from 211 miles of the Massachusetts coast. Nearly
23% of this total weight came from debris collected along 22 miles of
shoreline around Boston Harbor. In 1990, cleanup at Boston Harbor
beaches produced an average of 604 Ibs of trash per mile of beach. This
amount is two times the state average and five times the average for Cape
Cod beaches, but 30% less than the average weight of trash collected per
mile of beach in Boston Harbor in 1989.

The composition of the beach debris can provide some insight about the
possible sources of the litter. For example, plastic tampon applicators
and condoms are sewage-related wastes that escape treatment facilities
or are discharged through CSO pipes. According to data collected and
published by the Center for Marine Conservation, 17,125 tampon
applicators were removed from beaches nationwide during the 1990
cleanup effort. Approximately 38% of the national total was collected
from Massachusetts beaches; 6.5% came directly from Boston Harbor
shores.

The average number of tampon applicators collected per mile of beach in
1990 was the same as the average number in 1989; in other words, the
number of these sewage-related articles did not decline between 1989 and
1990. Although in 1988 MWRA implemented new methods for collecting
scum and floating debris such as tampon applicators, no beach cleanup
data were collected prior to that date to provide a measure of the
effectiveness of the scum and debris-collecting process in removing the
plastic applicators. Some sewage-related debris may still escape the
screening and skimming processes to be discharged with the effluent or
may enter the harbor through CSO discharges.

poner]

poss
Lenses

dene

a
|
{

In Boston Harbor,
fishing gear
and tampon

applicators made
up 50% of the
total “items of
concern”

Criteria for
grading the
aesthetic quality
of Boston Harbor
consider the
amount of debris
as well as the
type of debris

Aesthetics

EPA's "Items of Concern"

Tampon Applicators
Condoms

Syringes

Fishing Nets, Lures, Traps
Fishing Line, Rope
6-Pack Rings

Plastic Bags, Sheeting
Uncut Strapping Bands

In 1990, the EPA identified marine debris “items of concern.” This list
(see box) includes articles that endanger marine life, pose risks to human
health and safety, or significantly degrade aesthetics of the marine
environment. One approach to evaluating the aesthetic quality of
Boston Harbor can consider the total number of “items of concern.”
During the 1990 beach cleanup in Boston Harbor, 44,595 total items of
debris were collected and categorized on data cards. Approximately 20%
of the debris articles was from EPA's “items of concern.” This is an
alarming proportion when compared to 8% for the nation. For both
Boston Harbor and the state, fishing equipment and tampon applicators
made up half of the “items of concern.”

Evaluation

Because the perception of aesthetic quality is somewhat subjective and
because some of the conditions that influence overall aesthetic quality
cannot readily be quantified (odors, for example), the grading criteria
were developed to specifically include quantitative data. The beach
cleanups provide specific information on types and amounts of beach
debris, and are conducted on a regular annual schedule. Therefore, future
assessment of aesthetic quality can be based on the same criteria
developed for this report.

REPORT CARD
Is Boston Harbor Aesthetically Pleasing?
1990 1991
Aesthetics D D

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7. COMPARISON AMONG DIFFERENT AREAS OF
} BOSTON HARBOR

Although throughout this report we have graded Boston Harbor as a
whole, it is important to remember that this large area encompasses a
variety of physical environments. These different areas are affected by
i different sources of pollution. The quality of the marine environment
varies within the harbor, and the response to pollution abatement
programs will also be different in different areas.

) Figure 7-1 summarizes how conditions differ among the four different
areas of the harbor and its tributary rivers. Data are not available for all
a pollution problems for all regions, but it is clear that the inner harbor is
a the worst area for bacterial contamination, low dissolved oxygen
‘ concentrations, and toxic contamination. The inner harbor is in poor
condition, even though it is less affected by treatment plant discharges
j than are outer harbor regions. Many sources contribute to the
\ degradation of the inner harbor, including CSOs, street runoff,
contaminated storm sewers, commercial and recreational ship traffic,
and leaching from old industrial sites. Other areas showing severe
degradation are the rivers tributary to Boston Harbor: the Charles, the
Neponset, and the Mystic. These rivers are affected by sources similar to
those affecting the inner harbor (except for commercial ship traffic
which only affects the lower Mystic River).

Thus, although sewage from the treatment plants is the single largest
source of pollution to Boston Harbor, smaller sources can cause more

j severe local environmental impacts. The Boston Harbor Project is

' necessary for the recovery of Boston Harbor, and will especially benefit
the outer harbor areas, but in order to achieve all the desired uses of the
harbor in the future the smaller sources of pollutants must also be
addressed.

mi 71

Comparison Among Areas in the Harbor

REPORT CARD FOR

Boston Harbor, by geographic area

Overall

Inner Northwest

Central Southeast Tributaries

IS IT SAFE TO SWIM AND BOAT?
Swimming
Boating

noo

C+
A-

IS IT SAFE TO EAT FISH AND SHELLFISH?
Shellfish: Pathogens
Fish/Shellfish: Organic Contamination
Fish/Shellfish: Metal Contamination

ARE MARINE RESOURCES PROTECTED?
Sediment Contamination
Water Quality: Oxygen
Water Quality: Toxic Contamination
Fish Disease
Seafloor Animals

D-
Cc-

C-
A- D-

1S THE HARBOR AESTHETICALLY PLEASING?
Aesthetics

OVERALL GRADE

Puget Sound),

Francisco Bay}.

environment.

7-2

Grading system used for the Boston Harbor report card

A EXCELLENT: Consistently maintains conditions characteristic
of other clean coastal sites (e.g., Provincetown Harbor).

B GOOD: Frequently is better than Federal and State water quality
standards and expectations for an urban estuary (e.g., some of

C_ SATISFACTORY: Complies with Federal and State water quality
standards and meets expectations for an urban estuary (e.g., San

D POOR: Sometimes fails to comply with existing standards or meet
expectations for an urban estuary; some uses of the harbor
are maintained (e.g., Boston Harbor last year).

Figure 7-1. Geographic variation in environmental quality in Boston Harbor. The inner
harbor has the worst environmental quality, while the southeastern harbor has the healthiest

ae
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; 8. HOW WILL THE HARBOR BENEFIT, NOW THAT
; SLUDGE DISCHARGES HAVE STOPPED?

One of the worst aspects of metropolitan Boston's inadequate sewage
treatment has been the decades-long practice of dumping sewage sludge
f into the waters.of Boston Harbor. Discharged on every outgoing tide,
| sludge has contributed huge amounts of pollutants to Boston Harbor and
Massachusetts Bay: 23,000 tons of total solids, 15,000 tons of BOD
(biochemical oxygen demand, a measure of how much oxygen-consuming
A matter is in the waste) and more than 1,000 tons of the nutrients
i nitrogen and phosphorous per year. Sludge was the second most
important source of solids, BOD, nutrients, toxic metals, and PAHs to the
24 harbor and bay. In 1991, the primary-treated effluent discharged by the
1 two treatment plants contributed 5 to 6 times more of these pollutants
: (Figure 8-1) than sludge.

\ Despite the intentions of the designers of the treatment plants, who

| hoped that tidal currents would disperse the sludge to Massachusetts Bay,
recent studies showed that most of Nut Island sludge and some of Deer
Island sludge (approximately 7,200 tons per year) returned to the harbor
on the incoming tide. Most of the environmental impacts of sludge in the
harbor have been on the sediments: sludge particles and their associated
contaminants have settled and accumulated near the Nut Island sludge
outfall at the tip of Long Island and in more distant depressions and
embayments, Sewage particles have accumulated in some parts of the
harbor to form a black, oozy mud, devoid of life. Contrary to popular
belief, there are no plans to dredge and remove these contaminated

, sediments, because the resuspension of contaminants caused by dredging
would cause more environmental damage.

Stopping the sludge discharges means that the amount of sewage solids
accumulating in the harbor has decreased by about 20%--effluent still
contributes approximately 31,000 tons of sewage solids to the harbor
annually. As primary treatment becomes more efficient, and more
solids end up in the sludge, the pollution load to our waters will decrease
even more.

Since December 1991, no sludge has been put into the water. Instead, it is
oy being converted into fertilizer pellets at MWRA's new processing plant in
| Quincy. Some changes after the sludge discharge stopped are
. immediately noticeable. Other improvements will take months to a few
years, while the most fundamental recovery processes will happen over
years to decades,

a! 8-1

Sludge J

Biochemical 4
Oxygen Demand Nitrogen Lead 4
99,150 metric tons/yr 13,140 metric tons/yr 38,620 kg/yr
7™%

15%

ry
|
Ss
Polynuclear Aromatic -
Total Solids Copper Hydrocarbons 1
99,900 metric tons/yr 77,880 kg/yr 3,470 kg/yr ;
10% % 4

23%
28%

Figure 8-1, Relative loadings of sludge, effluent and other sources of pollutants. These pie

charts show the relative amounts of pollutants contributed by different sources. Sludge is .

the second most important source of most pollutants to Boston Harbor. "Other" includes a

atmospheric deposition, street runoff, and CSOs. ad
J

8-2

» Che

Keene

Sludge

Short-term Recovery (Days to Weeks)
Water Clarity and Aesthetics near the Sludge Outfall

The dense, black, foul-smelling plume of sludge from Nut Island, visible
at the northeast tip of Long Island on every outgoing tide, is gone. Because
the Deer Island sludge was mixed with the effluent, there was never a very
pronounced plume due only to sludge, so there is no dramatic effect at the
Deer Island discharge.

Bacterial Water Quality

Because the sludge could not be effectively disinfected, fecal coliform
levels near the Nut Island sludge discharge were often high--ranging up to
10,000 per 100 mL. Future monitoring should show a sharp decrease in
sewage indicator bacteria counts near the discharge, and decreases may
be detectable farther away at long-term MWRA monitoring stations.

There may also be fewer closure of clam flats near the airport; anecdotal
evidence has suggested that sludge may have contributed to bacterial
contamination of these beds when carried there by strong southeasterly
winds.

Medium-Term Recovery (Months to Years)
Hard-Bottom Communities

Although the harbor floor near Long Island is typical for New England
rocky coasts, few of the plants or animals characteristic of this habitat
can be found there. The area has been severely impacted by silt deposits,
probably from the sludge. Within the year, ocean currents should wash
the silt away, permitting the beginning stages of colonization by
characteristic New England rocky coastal species: kelp, sea urchins,
mussels and anemones. However, it will take years for the community to
reach maturity.

Longer-Term Recovery (Years to Decades)
Soft-Bottom Communities

_ Small worms, clams and snails live in sand or mud at the bottom of the
harbor and are important links in the harbor's food chain. Large areas
of soft-bottom communities near Long Island appear to be suffering the
consequences of sludge accumulation: they are dominated by a few
species usually found only in disturbed marine environments.
Eventually, as the reservoir of organic material and toxic chemicals is
depleted or covered up, more species will find these areas habitable, and
the impacted communities will develop into those typical of healthy
soft-bottom marine environments.

8-3

Sludge

Winter Flounder

Winter flounder collected in 1984 from Boston Harbor were reported to
have high rates of diseases like fin rot and liver abnormalities,
including cancers. Presumably, these fish were affected by the toxic
materials in sludge deposited on the bottom. The flounder may have
been exposed to toxic chemicals through direct contact with
contaminated sediment and by eating contaminated food organisms.
Recently, researchers from the Woods Hole Oceanographic Institution
have found that the flounder in the harbor are healthier now than in
1984. This improvement may correlate with the decreasing discharge of
toxic chemicals from the MWRA plants. Now that sludge is no longer
contributing toxic materials to the harbor, the physical health of the
flounder should continue to improve.

Stopping the dumping of sludge is a major milestone in the Boston
Harbor Project. Because sludge has been accumulating for years, the
most important improvements will take years to be fully realized. These
environmental changes will be difficult to distinguish from the effects of
better primary treatment and moving the effluent discharge offshore.
Nevertheless, the abatement of sewage sludge discharges is critical for
the recuperation of our marine environment from decades of abuse.

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APPENDIX
Evaluation Criteria for Grades in 1991 Report Card.

As mentioned in-the Introduction, many of the comments we received on the 1990
State of Boston Harbor report were that the grades as assessed were too subjective,
and that MWRA should investigate better ways of quantifying our grade scales. For
most of the grades given in this report we have reevaluated our grading criteria,
relating grades to conditions that may form a public health threat or that violate state
or federal standards.

Depending on the amount of information available, we calculated the grades in one of
two different ways. For parameters where very limited geographic data are available,

‘such as toxic chemicals in the flesh of fish and shellfish, we pooled all available

recent data and graded the harbor as a whole. For parameters where adequate data
were available to grade the subregions separately, we did so. We then weighted the
grades from the subregions by the area of the regions, and calculated an average
grade for the harbor. Table 1 describes the computation of the harbor-wide grade for
dissolved oxygen in the water column. We did not include the tributaries in this
grading.

Table A-1: Calculating a weighted average grade for dissolved oxygen
in the water column. The region grades were based upon
MWRA 1989 and 1990 harbor monitoring data.

Area Percent of Grade, Grade Point, Weight,
Subregion (Acres) Total (A) Region Region (B) (A * B)
Inner Harbor 2,479 11 % D 1.0 0.11
Northwest 6,611 29 % B 3.0 0.87
Harbor
Central Harbor 7,438 33 % B 3.0 0.99
Southeast 5,991 27 % B 3.0 0.81
Harbor

Total 22,519 100 % 2.78/4 = B-

Section 3: Ts it Safe to Swim?
Bacterial Water Quality

We developed grades to, evaluate the safety of Boston Harbor waters for swimming
and for boating based upon (1) interviews with microbiologists who study human
pathogens in surface waters and (2) a thorough review of the literature. The
swimming grades are based upon state and EPA criteria for bacterial indicators of
sewage pollution in ‘surface waters.

Although the cause and effect association between swimming in sewage-contaminated
water and incidence of disease has been relatively well defined, little information is
available on the potential risks resulting from limited ingestion of or skin contact with
contaminated water such as may occur during boating. The state water quality
standard for fecal coliform bacteria in waters designated for secondary contact

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(boating) requires that (1) fecal coliforms not exceed 1000 organisms/100 mL and that
(2) 10% of the water samples do not exceed 2000 organisms/100 mL. For waters in”
which human contact is infrequent, EPA guidelines specify that enterococci bacteria
do not exceed 500 organisms/100 mL.

We decided to assign Boston Harbor waters that meet the Massachusetts surface
water standards for secondary contact (ie., boating) a grade of "C" (ie., waters are
acceptable for this use). Because some boating activities involve significant contact
with water (for example windsurfing) we assigned grades higher than a "C" based on
the standards for swimming. Grades "A" and "B" have been defined based on
standards that would protect swimmers, water-skiers, and wind-surfers.

Section 4: Is it Safe to Eat Fish and Shellfish?

Shellfish: Pathogens

The criteria for grading the safety of eating shellfish from Boston Harbor are based
on the availability of open or conditionally opened shellfish beds in Boston Harbor.

Shellfish: Toxic chemicals

We evaluated chemical contamination in fish and shellfish from Boston Harbor by
comparing average concentrations in edible tissue to:

. Concentrations in tissues from "clean" areas

. Risk-based levels derived using Massachusetts DEP guidance

. FDA action levels for PCBs, pesticides, and mercury, and a derived action level
for carcinogenic PAHs.

As mentioned in the text, risk-based concentrations for carcinogenic compounds are
concentrations in seafood calculated to cause a given increase in the lifetime risk of
cancer above the background cancer risk of approximately 1 case per 5 persons per
lifetime. Table A-2 shows the risk-based concentrations we derived for potentially
carcinogenic organic compounds.

For chemicals that are not thought to cause cancer, the risk-based limits were set in
relation to reference doses that are unlikely to cause adverse health effects during a
lifetime. Target levels for these chemicals are evaluated by comparison of tissue
concentrations to available Risk Reference Dose (Rf{D) or Acceptable Intake Chronic
(AIC) values. To be consistent with risk-assessment methodology used by the
Massachusetts Department of Environmental Protection (DEP), these levels are based
on 20 percent of the RfD value (see DEP, 1989). Table A-3 shows the reference
doses we derived for non-carcinogenic compounds. Development of the risk-based
criteria is described in more detail in Menzie et al. (1991).

A-4

cena
hard

Table A-2: Concentrations (ppm wet weight) of Organic Contaminants in Edible
Tissues. Concentrations are Shown for Three Lifetime Risk Levels*
and FDA Limits.

1 in 1,000,000. 1 in 100,000 1 in 10,000 FDA Limits

PCBs 0.0014 0.014 0.142 2.0
DDTs 0.032 0.32 3.25 5.0
PAHs 0.001 0.01 0.11 -

Assumes ingestion rate of 6.5 g/day

We used mean tissue concentrations calculated by NOAA (1991a) to estimate human
health risks associated with eating fish and shellfish from the harbor. For flounder
and lobster this involved comparison of the risk-based concentration levels to the
average tissue levels calculated for flounder and lobster from the harbor. For blue
mussels the NS&T Mussel Watch data were examined with respect to individual
harbor locations. In cases where tissue. data were reported as dry weights, we >
converted them to wet-weight equivalents using the U.S. Food and Drug
Administration (FDA) factors to allow comparison with the FDA action levels and
estimated risk-based guidelines. For example, to convert dry weight concentrations for
mussels to wet weights, multiply by 0.167

Table A-3: Target-level Concentrations (ppm wet wt) of Metal Contaminants in
Edible Tissues.
Target Level Comments
(ppm _ wet wt)

Mercury 1 FDA limit
Cadmium 2.1 DEP Risk Value of 0.2 Rf£D at ingestion rate of
6.5 g/day. EPA risk-based target level is 11 ppm.
Lead 3 Derived from EPA's Integrated Uptake Biokinetic Model
(JU/BK) for lead concentrations in children.
Copper 89.2 DEP Risk Value of 0.2 RfD at ingestion rate of
6.5 g/day. EPA risk-based target level is 430 ppm.
Chromium 12.3 Chromium VI; DEP Risk Value of 0.2 RfD at ingestion
rate of 6.5 g/day. EPA risk-based target level is 54 ppm.
Nickel 43 EPA risk-based target level.
Zinc ~=—SS—=«AO DEP Risk Value of 0.2 RED at ingestion rate of

6.5 g/day. EPA risk-based target level is 2150 ppm.

Arsenic 21 DEP Risk Value of 0.2 RfD at ingestion rate of
6.5 g/day. EPA risk-based target level is 11 ppm.

The grading scheme ‘we developed incorporates (1) FDA action levels, (2) an
estimated “action level" of 1 ppm for carcinogenic PAH compounds based on the 2
ppm FDA level for PCBs, and (3) risk-based criteria. We made some simplifying
assumptions in the development of the criteria for Boston Harbor. We assume an
average fish and shellfish ingestion rate of 6.5 g/day (approximately one quarter
ounce/day). This is the consumption rate used by EPA in the development of Water
Quality Criteria for protection of human health. It is probably higher than the
average ingestion rate of fish and shellfish from the harbor. For example, EPA
(1988b) used a lower rate as an average for estimating risks of eating fish (1 g/day)
and lobster (2.1 g/day) from Quincy Bay. Thus, the risk-based criteria we used are
probably somewhat conservative for the average person, that is the criteria may
overestimate the small risks associated with consumption of seafood from the harbor.
However, it is likely that a small fraction of the population may consume more than
6.5 g/day, particularly if harbor fish and shellfish are relied on for subsistence (EPA
1988a,1988b). :

A-6

ons

ened

Section 5: Are Fish and other Marine Resources being Protected?
Water Quality: Dissolved Oxygen

We developed grades for dissolved oxygen in the water column based upon
Massachusetts State water quality criteria. Regions graded an "A" have DO would
meet the Class SA criteria 99 percent of the time. Regions graded a "B" would meet
the State Class SB standard 99 percent of the time. Progressively lower grades
indicate an increasing frequency or severity of violations of the DO water Quality
Standard.

bese es

Water: Toxic Contaminants
Sediments: Toxic Contaminants %y
L 3
We were unable to quantify grading schemes for toxic contaminants in either the
water column or in the sediments. Therefore, grades for these parameters are based y
upon the same relative criteria as the grades assessed last year. These evaluations 5
are based upon comparisons of conditions in Boston Harbor to other urban estuaries.
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Living Resources: Winter Flounder

We evaluated the health of the winter flounder population in Boston based upon the
results obtained in "Fish Day 1989", as described in the text. The grading scale is
based upon an index compiled by O'Connor ef al. (1987).

In 1991. these fin rot data were supplemented by data collected by Moore ef al.
(1991) on the prevalence of liver lesions in winter flounder and a pre-cursor to such
lesions, the occurrence of hydropic vacuolation in liver cells. NOAA will be releasing
a study this spring that reports this measure of flounder health for fish throughout
New England. . A grading scale for this measure is reported below. Currently both
fin rot and histopathology criteria result-in the same grade for the harbor.

Living Resources: Sea-Floor (Benthic) Communities

Gathering data on soft-bottom benthic communities involves taking a sample of the
bottom using. any of a variety of devices collectively known as grabs or corers. The
sediment in the grabs are sieved through a fine-mesh screen, typically one with a
either a 0.5 mm or a 0.3 mm mesh (0.3 mm = 12 thousandths of an inch), and
preserved with formaldehyde. In the laboratory, the preserved sample is sorted under
a microscope and the animals are counted and identified.

Benthic communities are normally very "patchy", with large differences between
stations in the species present and their abundances, and at stations between sampling
periods. There are even noticeable differences in replicate samples taken in the same
location at the same time. Therefore, the data resulting from benthic studies is quite
complex, usually requiring sophisticated statistical analysis and experience with the
communities in an area before trends such as those described in Section 5 are seen.
Even then, the results of such analyses are often too esoteric to explain easily to
environmental managers or to the general public.

The development of a simple index that could be used to grade the condition of
benthic communities has been an area of intense work during the past two decades.
Unfortunately, benthic communities are complex enough that none of the proposed
schemes have shown themselves to be of general utility. An index that works well
with data from one study or area may break down completely when applied to other
benthic communities.

In attempting to quantify grades given to the soft-bottom benthic communities in
Boston Harbor we restricted ourselves to considerations of the numbers of species
present in samples taken within Boston Harbor. This is one estimate of species
diversity, an aspect of benthic communities that is well known to have a negative
association with the level of pollution enrichment. The number of species present in
a sample is influenced by the area of the bottom sampled. Since larger grabs sample
more species from a benthic community, we restricted ourselves to comparing data
from studies using roughly comparable sample sizes. The studies reviewed included
the environmental assessments carried out by the MDC in 1978 - 1984 during its
application for a waiver of secondary treatment requirements (summarized in Blake er
al, 1989), benthic sampling carried out by the U.S. Army Corps of Engineers in the
inner harbor, and sampling performed by MWRA.

The data available on harbor communities do not support the development of a 5-
grade scale. We decided to develop a four grade scale of A, B, C/D and F; to
correspond roughly to conditions that are Good, Impacted, Degraded, and Highly
Degraded. This scale was developed only to intercompare the different regions within
the harbor, and is not intended to suggest, for example, that an area graded as an "A"
is completely un-impacted by pollution.

A- 10

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Naoccunall

Noted

The similarities in terms of what types of species are present (species composition)
and the diversity of species in benthic communities in parts of the central and
southeast harbors to much cleaner areas outside of Boston Harbor has been well
documented (Blake et al, 1989). We decided that those samples with the most
species present would set the end-point for determining what number of species at a
station received an "A". We also compared the species number in the historical data
to the more complex information available on species composition, which means
looking at the types of species present, how they feed, or if they are recognized as
either sensitive to or resistant to pollution. Using this information we set the species
number cutoffs for the grades below "A".

Table A-4 illustrates the process followed, and contains the station identifiers, number
of species present, and assigned grade for the grading the central and southeast
harbors. All of the data for these regions are from the 1978-84 MDC surveys, which
were reviewed and summarized in Blake et al. (1989).

A- iL

yy
Table A-4 Calculating an average grade for the benthic (sea-floor) 3
community in the central and southeast harbors.
y
Station name Number of Species Grade Assigned Grade Point i
T13 25 c/D 15
T14 40 C/D 15
T15 68 B 3
T16 33 c/D 15 4
T17 71 B 3 cf
T18 59 B 3
T19 50 B 3 fa
T20 69 B 3 4
T21 50 B 3 :
T22 . 77 B 3 a
NI 43 C/D 1.5 :
Bll : 87 B 3
Bi2 105 A 4 2
B9 45 C/D 1.5 4

Number of Stations: 14 Total Grade points = 47 Average = 35.5/14 = 2.5 = C/D

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A- 12

Section 6: Is the Harbor Aesthetically Pleasing?

We assigned grades to harbor aesthetics, on the basis of the amount of debris
collected per mile of beach during the 1990 beach cleanup and also considering the
total number of debris items on EPA's list of "items of concern". A single grade was
assigned to Boston Harbor and, for comparison, to the north shore, south shore, and
Cape Cod regions. The amount and types of debris collected in each one of these
areas are compared to state and national averages obtained from the Center for
Marine Conservation'’s (CMC) National Marine Debris Database.

: collected.

A- 13

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BIBLIOGRAPHY

1: The Problem and the Plan

MWRA, 1990. The State of Boston Harbor: 1990. Massachusetts Water Resources
Authority, Boston, MA.

2: Understanding the Problem

Knebel, H.J., R-R. Rendigs, R. N. Oldale, and M.H. Bothner. 1991. Sedimentary
framework of Boston Harbor, Massachusetts. Journal of Sedimentary
Petrology, Vol. 61, No. 5, pp. 791-804.

Lee, J.-J. 1990. Contaminated sediment transport in Boston Harbor. M.S. thesis,
Massachusetts Institute of Technology Department of Civil Engineering,
Cambridge, MA.

McDowell, S., J. Ryther, Jr., and C. Albro. 1991. Field studies of Nut Island sewage
plumes and background water properties in Boston Harbor:
October-November 1990. MWRA Environmental Quality Technical Report 91-
7, Boston, MA,

Meade, R.H. 1972. Sources and sinks of suspended matter on continental shelves.
In Shelf sediment transport: process and pattern, D.J. P. Swife et al., eds.
Dowden, Hutchinson, and Ross, Inc., pp. 249-262; cited in Lee, 1990.

Menzie-Cura and Associates. 1991. Sources and Loadings of Pollutants to
Massachusetts Bay. Draft report to the Massachusetts Bays Program, Boston,
MA, April, 1991.

Menzie, C. A., J. J. Cura, J. S. Freshman, and B. Potocki. 1991. Boston Harbor:
Estimates of Loadings. MWRA Environmental Quality Technical Report 91-4,
Boston, MA.

MWRA. 1991. Combined Sewer Overflow Receiving Water Monitoring, Boston
Harbor and Tributary Rivers, June 1989-October 1990. MWRA Environmental
Quality Technical Report 91-2, Boston, MA.

Sullivan, P.A. and Robinson, W.E. 1990. The health of winter flounder from
Boston Harbor: A summary of the results from "Fish Day",
May 13, 1989. Report by the New England Aquarium. to MWRA, Boston, MA.

Signell, R. 1991. Applications and limitations of depth-averaged circulation.
modeling in Boston Harbor, Massachusetts. M. Spaulding, ed., Proceedings of
the Second Estuarine and Coastal Modeling Conference, Tampa, Florida, Nov.
1991, in press.

8: Is Boston Harbor Safe for Swimming and Boating?
Adams, E.E. and X. Zhang. 1991. Impact of CSO's on Boston Harbor: A new look
based on 1990 data. MMWRA Environmental Quality Technical Report 91-9,
Boston, MA.

Boston Water and Sewer Commission. 1990. Combined Sewer Overflow
Monitoring Report, Second Quarter, August 15, 1990, Boston, MA.

Bibliography

MWRA, 1991. Combined Sewer Overflow Receiving Water Monitoring, Boston
Harbor and Tributary Rivers, June 1989-October 1990. MWRA Environmental
Quality Technical Report 91-2, Boston, MA.

Normandeau Associates, Inc. 1991. A spatial and temporal analysis of Boston
Harbor Microbiological Data. MWRA Environmental Quality Technical
Report 91-3, Boston, MA.

Robinson, W.E., T.J. Coffey, and P.A. Sullivan. 1990. New England Aquarium's
Ten Year Boston Harbor Monitoring Program. First Report (March 1987 - July
1989). New England Aquarium, Boston, MA.

4: Is It Safe To Eat Fish and Shellfish?

Battelle. 1988. Mussel Watch 2-Year Report. Report to the National Oceanic and
Atmospheric Administration, Rockville, MD.

Battelle. 1990. Phase IV Final Report, National Status and Trends Mussel Watch
Program. Collection of Bivalves and Surficial Sediments From Coastal U.S.
Atlantic and Pacific Locations and Analysis for Organic Chemicals and Trace
Elements. Report to U.S Department of Commerce, National Oceanic and
Atmospheric Administration, Ocean Assessments Division, Rockville, MD.

DEP (formerly DEQE). 1989. Guidance for disposal site risk characterization
and related Phase II activities-in support of the Massachusetts contingency
plan. Massachusetts Department of Environmental Quality Engineering,
Office of Research and Standards. May 17, 1989.

Menzie, C. A., J. J. Cura, J. S. Freshman, and B. Potocki. 1991. Boston Harbor:
Estimates of Loadings. MWRA Environmental Quality Technical Report 91-4,
Boston, MA.

Metcalf & Eddy, Inc. 1988. Review of Historical Data for Characterization of
Quincy Bay Contamination: Task I Report. Prepared for U.S. Environmental
Protection Agency, Water Quality Branch, Boston, MA.

Metcalf & Eddy, Inc. 1988. Analysis of Risks from Consumption of Quincy Bay
Fish and Shellfish. Prepared for U.S. Environmental Protection Agency,
Water Quality Branch, Boston, MA.

Metcalf & Eddy, Inc. 1988. Summary Report for Assessment of Quincy Bay :
Contamination: Task V Report. Prepared for U.S. Environmental Protection
Agency, Water Quality Branch, Boston, MA.

NOAA. 1988. National Status and Trends Program Benthic Surveillance Project:
Summary Report, 1984-86. U.S. Department of Commerce, National Oceanic
and Atmospheric Administration, National Marine Fisheries Service,
Northeast Fisheries Center.

NOAA, 1991a. Status and trends in concentrations of selected contaminants in
Boston Harbor sediments and biota. NOAA Technical Report NOS OMA 56.
U.S. Department of Commerce, National Oceanic and Atmospheric
Administration, Seattle, WA.

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Nees

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ar

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Cot

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NOAA. 1991b. Second summary of data on chemical contaminants in sediments
from the National Status and Trends Program. NOAA Technical Report NOS

OMA 59. U.S. Department of Commerce, National Oceanic and Atmospheric
Administration, Rockville, MD.

U.S. Environmental Protection Agency. 1987. Guidance Manual for Assessing
Human Health Risks from Chemically Contaminated Fish and Shellfish
Report C723.

2 U.S. Environmental Protection Agency. 1988a. A Histopathological and
j ; Chemical Assessment of Winter Flounder, Lobster and Soft-Shelled Clams
Indigenous to Quincy Bay, Boston Harbor, and an in situ Evaluation of
. Oysters Including Sediment (Surface and Cores) Chemistry. Task I and Il
pol Report. Environmental Research Laboratory, Narragansett, RI.

U.S. Environmental Protection Agency. 1988b. Analysis of Risks from
Consumption of Quincy Bay Fish and Shellfish. Task IV Report. Prepared
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5: Are Fish and Other Marine Resources Being Protected?

Blake, J.A., N.J. Maciolek, and P. Rosen, 1989. Benthic Infaunal Communities of
Boston Harbor. Report to the Massachusetts Water Resources Authority,
Boston, MA.

Boehm, P.D., W. Steinhauer, and J. Brown. 1984. Organic Pollutant
Biogeochemistry Studies Northeast U.S. Marine Environment. Part 1: The
State of Organic Pollutant (PCB, PAH, Coprostanol) Contamination of the
Boston Harbor - Massachusetts Bay - Cape Cod Bay system: Sediments and
Biota. Final Report from Battelle Ocean Sciences to the National Oceanic and
Atmospheric Administration, Rockville, MD.

Carr, R.S., R.E. Hillman, and J.N. Neff. Field assessment of biochemical and
histopathological indicators of stress for winter flounder. Unpublished
manuscript, Battelle, Duxbury, MA.

Couch, J.A., and D.R. Nimmo. 1974. Detection of interactions between natural

A pathogens and pollutants in aquatic animals. In: Hood, M.A. and R.R, Miller
(eds). Proceedings Gulf Coast Regional Symposium on Diseases of Aquatic
Animals. Louisiana State University, Cent. Wetland Resour. Pub. No. LSU-SG-
74-05.

pian

Gallagher, E.D. and J.P. Grassle. 1989, Assessment of the Savin Hill and Fox
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| Combined Sewer Overflow, 1987. Executive Summary. Report to the
, Massachusetts Dept. of Environmental Protection, Boston, MA.

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Gilbert, T., G.C. McLeod, R. Maehl, K.V, Ladd, A. Clay, and A. Barker. 1972. Trace
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Hubbard, W. A. and RJ. Bellmer. 1989. Biological and chemical composition of
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Isaac, R.A. and J. Delaney. 1972. Toxic Element Survey. Progress Report No. 1.
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Long, E.R. and L.G. Morgan. 1990. The Potential for Biological Effects of
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Malins, D.C., B.B. McCain, D.W. Brown, M.S. Myers, M.M. Krahn, S-L Chan. 1984.
Toxic chemicals, including aromatic and chlorinated hydrocarbons and their
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the vicinity of Los Angeles. Environmental Science & Technology 21:765-770.

Mearns, AJ., and M.J. Sherwood. 1977. Distribution of neoplasms and other
diseases in marine fish relative to the discharge of waste water. Ann. N.Y.
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Michael, A. and C. Menzie. 1991. An evaluation of rapid benthic assessment.
Report by Menzie-Cura and Associates, Inc. to the MWRA, March, 1991.

Moore, M.J. 1991. Vacuolation, proliferation and neoplasia in the liver of
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dissertation, MIT/WHOI Joint Program in Oceanography.

Moore, M.J., B.R. Woodin, and J. J. Stegeman. 1991. Liver pathology of
winter flounder: Boston Harbor, Massachusetts Bay, and Cape Cod Bay--
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Murchelano, R.A. 1988. Fish as Sentinels of Environmental Health. U.S.
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Murchelano, R.A., and R.E. Wolke. 1985. Epizootic carcinoma in winter
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8: How Will the Harbor Benefit, Now that Sludge Discharges Have Stopped?

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Sebens, K.P. and J. D.Witman. 1990, Effects of sewage effluent and sludge outfall
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4 MWRA, Boston, MA.

REPORT CARD FOR Boston Harbor
1991 1990
iS IT SAFE TO SWIM AND BOAT?
Swimming D+ D
Boating B (not graded)
IS IT SAFE TO EAT FISH AND SHELLFISH?
Shellfish: Pathogens D+ D-
Fish: Organic contamination C- C-
Fish: Metal contamination B- B-
ARE MARINE RESOURCES PROTECTED?
Sediment contamination D- D-
Water quality: Oxygen c C-
Water quality: Toxic contamination B- B-
Fish disease D- D-
Seafloor Animals D D-
IS THE HARBOR AESTHETICALLY PLEASING?
Aesthetics D. D
OVERALL GRADE c- D+

eaten

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NOAA. 1987. National Status & Trends Program—Draft Interpretive Report,
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NOAA, 1991a. Status and Trends in concentrations of selected contaminants in
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O'Connor, J.S., J.J. Ziskowski, and R.A. Murchelano. 1987. Index of Pollutant-
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Robinson, W.E., T.J. Coffey, and P.A. Sullivan. 1990. New England Aquarium's
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1989). New England Aquarium, Boston, MA.

SAIC. 1990. REMOTS® Sediment-Profile Photography Surveys of Boston
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Sass, S.L., and R.A. Murchelano. 1988. Hepatic tumors and other liver pathology
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ere |

Lebvmaed

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jaded eaentceed

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ay
Aneel

Wallace, G.T., J.H. Waugh, and K.A. Garner. 1988. Metal distribution in a major
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Malibar, FL. ~

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my
i
id

Williams, J.W. 1981. The Occurrence of Fin Erosion in Winter Flounder,
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pron

6: Is Boston Harbor Aesthetically Pleasing?

Maciolek, N. 1990. Report on Floatable Debris on Boston Harbor Beaches.
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Charlestown Navy Yard
100 First Avenue
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