United States
Environmental Protection
Agency
ERL-Narragansett
South Ferry Road
Narragansett Rl 02882-1198
401 782-3000
EPA-600/8-89/084
ERL-N TT-02
November 1989
vvEPA
A Framework for
Real-Time
Decision-Making
New Bedford Harbor
Pilot Dredging Study
Pre-Operational Data
and
Site-Specific Criteria
Decision
Criteria
Committee
Operational
Data Analysis
Real-Time
Monitoring
Better
Environmental Decisions
U.S. Environmental Protection Agency
GLNPO Lil.jry Collection (PL-12J)
77 West Jackson Boulevard,
Chicago, II 60604-3590
-------
PREFACE
Numerical water quality criteria have been employed by EPA in the
protection of the environment for decades. Biological tests and analytical
chemical procedures have been developed to assess the state of environmental
quality based on these criteria. Numerous monitoring programs have been
implemented to collect those data necessary to make decisions based on
criteria values.
This technology transfer document provides an overview of a unique project
that incorporates each component listed above into a "real-time" decision
making framework. It was successfully used in a pilot study to determine
whether dredging posed an "unacceptable" hazard as a remediation option at the
New Bedford Harbor Superfund Site in Massachusetts. It represents a framework
that can be employed at other locations to provide environmental protection
during clean-up operations.
The successful completion of this project is the result of a team effort of
over 80 individuals from the Federal and contract staff at our laboratory, as
well as EPA Region I, the U.S. Army Corps of Engineers, and the State of
Massachusetts' Department of Environmental Protection. This effort was part of
a pilot study, therefore, any comments, suggestions, or other input are
welcome.
William G. Nelson, Ph.D
Project Coordinator
Environmental Research Laboratory
Narragansett, RI 02882
U.S. Enviror~ action Agency
Region 5, Li: . ••.}
77 West Jack-... ^,,,,,/ard, 12th Floor
Chicago, IL 60604-3590
-------
INTRODUCTION
New Bedford Harbor (NBH) is located
along Buzzards Bay between the cities
of New Bedford and Fairhaven,
Massachusetts (Fig. 1). Since the
1940' s, electronics and manufacturing
companies in the area have discharged
effluents containing polychlorinated
biphenyls (PCBs) into the Acushnet
River and the harbor. High PCS
concentrations in river and harbor
sediments were first documented in 1974
(Connelly and St. John, 1988). Over the
past 15 years, nearly 18,000
acres of PCB- and heavy metals-
•Long istanti SounO
UQOBT Bmzartt B«v
'3 000 9.000 IM
FIGURE 1.
contaminated sediment have been identified, with PCB concentrations as high as
100,000 parts per million (ppm) in some areas of the upper harbor. In 1982,
the site was added to the Environmental Protection Agency's (EPA) National
Priorities List of hazardous waste sites slated for cleanup under the
Super fund Act.
A feasibility study conducted by EPA in 1984 proposed several
alternatives for the remediation of NBH. One option common to most
-------
remediation alternatives included dredging contaminated sediments out of the
harbor. Federal, State, and local officials, as well as the public, expressed
concern over dredging. Many believed that sediments resuspended during
dredging would cause the release of contaminants that would affect biota
inhabiting both the harbor and Buzzards Bay. Others cited potential pollution
problems from contaminated water (leachate) leaking from the proposed disposal
site (Averett and Francigues, 1988).
In order to address these concerns, the EPA decided to pre-test dredging
and possible disposal options. Working with the U.S. Army Corps of Engineers
(COE), EPA Region I designed a pilot study to examine dredging as a
remediation option for the Superfund Site. A monitoring plan (including
biological, chemical, and physical measurements) for all aspects of the Pilot
Project was designed and implemented by EPA's Environmental Research
Laboratory, Narragansett, R.I. (ERL-N). This technical transfer document
summarizes the decision-making process and the "real-time" monitoring data
used by project managers to assess the environmental "acceptability" of the
dredging operation on a day-to-day basis. Subsequent publications will provide
greater detail of the monitoring program with respect to evaluation of
dredging and disposal options.
PILOT DREDGING PROJECT DESCRIPTION
The NBH Pilot Project was designed to examine and compare the efficiency
and effects of three hydraulic dredges and two disposal methods for use in a
possible large scale remediation with more highly contaminated sediment at the
NBH Superfund Site. The COE selected dredges capable of removing sediment with
-------
minimal resuspension as well as their ability to operate in the shallow water
at the Pilot Study site. The two disposal methods investigated included: 1) a
confined disposal facility (CDF), which required construction of a containment
dike partially in-water and partially on land; and 2) a confined aquatic
disposal cell (CAD), an in situ underwater disposal method (Otis, 1987).
MONITORING STRATECT/PECISIOM-MAKING FRAMEWORK
Evaluations of possible unacceptable contamination due to dredging during
the Pilot Study was complicated by the fact that Federal and State water
quality standards for PCBs and certain heavy metals were exceeded in NBH under
preoperational baseline conditions. In addition, the U.S. Food and Drug
Administration (FDA) action level for PCBs in seafood was exceeded and
sediments were known to be toxic.
Because of these special conditions, typical monitoring program and
management strategies were inappropriate. Therefore, it was necessary to
develop a unique site-specific monitoring/management strategy for NBH (Fig 2).
This framework included several
Pro-Operational Data
unique aspects: 1) the development I
, . .,. Decision Criteria
of a set of site-specific I
numerical decision values, the Decision Criteria Committee <*-
Decision Criteria, 2) the Construction/dredging Operational Data
establishment of a panel of Operational Data Analysis
(12-24 hr turnaround)
environmental managers, the A
Environmental Decision
Decision Criteria Committee (DCC),
to use those data in a timely manner, FIGURE 2.
-------
provide the necessary environmental data to the DCC in a rapid time-frame (12-
24 hours). This approach provided an effective feedback loop to evaluate,
modify or terminate the dredging operation if environmental risks were
unacceptable.
Each aspect of this strategy was successfully implemented. The site-
specific Decision Criteria were established for a number of physical,
chemical, and biological parameters based on data collected prior to the
initiation of dredging. The DCC was formed with representatives from each of
the principal parties involved in the study: EPA Region I, COE, Massachusetts
Department of Environmental Protection, and ERL-N. A monitoring plan was
developed to collect samples during the dredging and disposal operations,
complete sample analysis within 24 hours, and compare those results to the
Decision Criteria values. If the Decision Criteria values were exceeded, the
DCC could require engineering corrections to the dredging operation before
work was resumed, or termination of the project if environmental effects were
judged excessive. The Pilot Project was completed successfully and
environmental risks minimized by modification of dredging activities whenever
transitory increases above Decision Criteria values were detected.
MONITORING PLftN
The philosophy adopted by the DCC during this project was that some "short-
term environmental impact was worth long-term improvement in water quality."
Station locations for the Decision Criteria were selected to reflect this
principle. Some short-term minor increases in water chemical concentrations
and chronic biological impacts in the immediate vicinity of the dredging
-------
and chronic biological impacts in the immediate vicinity of the dredging
operation, at Station NBH-2, were considered acceptable. However, any far-
field impacts affecting Buzzards Bay were deemed not acceptable. This was
accomplished by including a second strategic station at the Hurricane Barrier,
Station NBH-4, representing the transition between NBH and Buzzards Bay.
The Pilot Project employed a suite of biological, chemical, and physical
monitoring techniques used at ERL-N. The biological procedures ranged from the
short-term acute and chronic methods used in the Complex Effluent Toxicity
Testing Program (CETTP) (US EPA, 1988) to in situ mussel deployments (Nelson,
et al., 1987). Before any operations were begun by the COE, baseline physical,
chemical, and biological measurements were completed. The biological
measurements were used to assess the effects of existing water quality on
plant and animal survival, growth, and reproduction. These tests served as a
benchmark against which increased contamination and/or toxicity associated
with the operational phases of the study were compared.
Five stations were selected for
water quality monitoring, four in NBH,
and a reference station in Buzzards
Bay (Fig 3). Station NBH-1
was located north of the dredge
site; Station NBH-7 was adjacent
to the cove where dredging
occurred; Station NBH-2 was at the
Coggeshall St. Bridge, the
transition point between the more
severely polluted upper harbor and
NEW BEDFORD HARBOR
FIGURE 3.
-------
point between NBH proper and Buzzards Bay.
The reference station for all water quality toxicity tests was
NBH-5, located at West Island in Buzzards Bay. Mussels were deployed at
stations NBH-2, NBH-3, NBH-4, and NBH-5. Only two of these stations, NBH-2 and
NBH-4, were used in the Decision Criteria because of their strategic
locations.
Seawater samples were collected separately for the ebb and flood tide at
each NBH station. Flow proportional collections at NBH-2 allowed estimation of
net transport. Each water sample was analyzed for total suspended solids,
PCBs, copper, cadmium, and lead. In addition, biological measurements were
completed including acute toxicity tests (survival of fish, mysids, mussels, a
red alga, and the sea urchin sperm cell fertilization test) and chronic
toxicity tests (fish growth, mysid growth and reproduction, mussel scope for
growth, and algal reproduction).
Once the operational phases of the Pilot Project began, water samples were
collected identical to those of the preoperational phase, however, the ebb
tide samples were returned to ERL-N immediately, and chemical analyses and
acute biological tests were completed overnight. These results were
transmitted to the Decision Criteria Committee prior to the start of that
days' dredging to assess any adverse environmental impacts and make any
necessary adjustments to the operation. This "real-time" monitoring allowed
the managers of this project to make timely decisions based on actual data,
thus ensuring the best degree of environmental protection possible.
-------
SUMMARY OF RESULTS
Total PCD (>
-------
exceeded at NBH-2, however, because this occurred during the same storm it was
judged not to be related to the operation.
Mussel Chemistry. Mussels deployed in NBH showed a distinct spatial and
temporal pattern with respect to PCB uptake. The PCB concentrations in mussel
tissues from the preoperational deployments were highest in the upper harbor
(NBH-2) and decreased moving down the harbor (NBH-4). PCB tissue
concentrations also increased with length of exposure. Concentrations of PCBs
in mussel tissues during the operational phases were not significantly
elevated, indicating no increased bioavailability of PCBs due to the dredging
operation.
Biological Tests. The short-term biological tests employed in this project
demonstrated sporadic toxicity immediately adjacent to the dredging area
(NBH-7). Reproduction in the red alga, Champia parvula, was consistently
reduced and on one occasion fertilization was reduced in the sea urchin
(Arbacia punctulata) sperm cell test. No effects were detected on growth or
survival in the sheepshead minnow, Cyprinodon variegatus, or on growth or
reproduction of the mysid, Mysidopsis bahia. The SFG of mussels never exceeded
the Decision Criteria values. The acute and chronic toxicity tests indicated
no unacceptable biological impacts from this project.
-------
CONCLUSIONS
The New Bedford Harbor Pilot Dredging Project demonstrated the utility of
biological, chemical, and physical monitoring techniques to evaluate, on a
"real-time" basis, the environmental risks of a dredging operation. A set of
site-specific criteria were developed and utilized by environmental managers
to assess, on a day-to-day basis, the impacts of this dredging operation on
water quality in NBH.
Monitoring data indicated that the dredging operation had a minimal effect
on existing water quality. On those occasions when elevated PCB concentrations
were detected, they were attributed to a specific causative operational
procedure or meteorological event. Operational modifications were implemented
effectively, thus limiting any environmental damage.
It would be unrealistic to expect to complete a Superfund remediation at
an aquatic site with absolutely zero short-term impact. However, this program
successfully established a set of limits (Decision Criteria) beyond which the
impact was considered unacceptable, and a mechanism (real-time monitoring
program) which provided the information necessary for environmental managers
(Decision Criteria Committee) to effectively oversee this project to
completion.
-------
References
Averett, D.E. and N.R. Francingues, Jr. 1988. A case study: dredqing as a
remedial action alternative for New Bedford Harbor, Massachusetts. Superfund
'88. Proceedings of the 9th National Conference. The Hazardous Materials
Control Research Institue, pp 338-342.
Connelly, J.P. and J.P. St. John. 1988. Application of a mathematical food
chain model to evaluate remedial alternatives for PCB-contaminated sediments
in New Bedford Harbor, Massachusetts. Superfund '88. Proceedings of the 9th
National Conference. The Hazardous Materials Control Research Institue, pp
359-362.
Nelson, W.G., O.K. Phelps, W.B. Galloway, R. Pruell, and P. Rogerson. 1987.
Effects of Black Rock Harbor dredged material on the scope for growth of the
blue mussel, Mytilus edulis, after laboratory and field exposures. Technical
Report D-87-7. Prepared by the U.S. EPA Environmental Research Laboratory,
Narragansett, R.I. for the U.S. Army Corps of Engineers Waterways
Experimental Station, Vicksburg, MS.
Otis, M.J. 1987. Pilot study of dredging and dredged material disposal
alternatives. Draft. U.S. Army Corps of Engineers, New England Division,
Waltham, MA.
Otis, M.J. and D.E. Averett. 1988. Pilot study of dredging and dredged
material disposal methods, New Bedford Harbor, Massachusetts Superfund Site.
Superfund '88. Proceedings of the 9th National Conference. The Hazardous
Materials Control Research Institue, pp 347-352.
U.S. Environmental Protection Agency. 1988. Short-term methods for estimating
the chronic toxicity of effluents and receiving waters to marine and estuarine
organisms. US EPA Environmental Research Laboratory, Cincinnati, OH. EPA
600/4-87/028
10
-------
U.S. Environmental Protection Agency
GLNPO Library Collection (PL-12J)
77 West Jackson Boulevard,
Chicago, IL 60604-3590
U.S.
Region 5, '
77 V/~-s- <-• •
9 I 1*^Ji w
------- |