EPA 90J-R-99-010
                                                             CBP/TRS 222/106
                                                             June 1999
           Targeting Toxics:  A Characterization Report
    A Tool for Directing Management & Monitoring Actions
               in the Chesapeake Bay's Tidal Rivers
       Basinwide Toxics Reduction and Prevention Strategy Commitment Report:
        A Supporting Document for the 1999 Toxics Reevaluation and Revision
                                          U.S. EPA Headquarters Library
                                               Mail code 3201
                                          1200 Pennsylvania Avenue NW
                                            Washington DC 20460
                    Chesapeake Bay Program
EPA
903-
R-
99-010
June 1999
                         Printed on Recycled Paper by the U.S. Environmental Protection Agency for the Chesapeake Bay Program

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 The Chesapeake Bay Program is a unique regional partnership that has been
leading and directing restoration of the Chesapeake Bay since 1983. The Bay
Program partners include the states of Maryland, Pennsylvania, and Virginia;
    the District of Columbia; the U.S. Environmental Protection Agency,
 representing the federal government; the Chesapeake Bay Commission, a tri-
      state legislative body; and participating citizen advisory groups.

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             Targeting Toxics: A Characterization Report
      A Tool for Directing Management and Monitoring Actions
                 in the Chesapeake Bay's Tidal Rivers
CX
                                June 1999
                                                  U.S.
                               Chesapeake Bay Program
                              410 Severn Avenue, Suite 109
                              Annapolis, Maryland 21403
                                 1-800 YOUR BAY

                             http://www.chesapeakebay.net
                  Printed by the U.S. Environmental Protection Agency for the Chesapeake Bay Program

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                            ACKNOWLEDGMENTS

       This Toxics Characterization would not have been possible without the commitment and
valuable expertise from members of the Regional Focus Workgroup over the past five years:

                                 Joe Winfield, Chair
                               Old Dominion University

                       Barry Gruessner, Chair from 1997 - 7/1998
                    Interstate Commission on the Potomac River Basin

                         John Kennedy, Chair from 1995 -1997
                      Virginia Department of Environmental Quality
                                           Dr. Beth McGee
                                           U.S. Fish & Wildlife Service

                                           Mark Richards
                                           Virginia Department of Environmental
                                           Quality

                                           Jim Stine
                                           Baltimore Gas & Electric
David Bailey
Potomac Electric Power Company (PEPCO)

Kelly Eisenman
U.S. EPA Chesapeake Bay Program Office


Lenwood Hall
University of Maryland
Wye Research & Education Center

Paul Jiapizian
Maryland Department of the Environment
       Other Regional Focus Workgroup members who were involved in developing the
Chesapeake Bay Chemical Contaminant Geographical Targeting Protocol in 1995 which served
as the basis for this Toxics Characterization are Dr. Steve Brown, Maryland Department of
Natural Resources; Dr. Ian Hartwell, Maryland Department of Natural Resources; Dr. Deirdre
Murphy, Maryland Department of the Environment; Dr. Haniette Phelps, University of the
District of Columbia; and Dr. Fred Pinkney, U.S. Fish and Wildlife Service.

       The Chesapeake Bay Program Office (CBPO) Toxics Characterization Team also
deserves recognition for acquiring and loading the data, preparing the data analyzation tools, and
coordinating the efforts of the Regional Focus Workgroup. The CBPO Team consists of Kelly
Eisenman, Toxics Coordinator, U.S. EPA CBPO; Brian Burch, GIS Coordinator, U.S. EPA
CBPO; Carrie McDaniel, Heather Daniel, and Kelly Mecum, Chesapeake Research Consortium;
and Christy Stoll, SAIC. Marcia Olson, NOAA Chesapeake Bay Office and Ananda
Ranasinghe, Versar, are recognized for their expertise in benthic community data analysis.

       For objective outside review of the public and technical characterization reports, we
recognize Richard Batiuk, U.S. EPA CBPO; Greg Bowen, Calvert County; Jack Greer, Maryland
Sea Grant; Wink Hastings, National Park Service; Jim Keating, U.S. EPA; David O'Neill, Center
for Chesapeake Communities; Steve Stewart, Baltimore County DEPRM; and Lori Shirley, City
of Bowie.

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                               TABLE OF CONTENTS

Executive Summary	iii

I.      Why was this characterization conducted?	.....................................—..........................1
A.     Purpose of this report	1
B.     Background information	1
            Toxics and the Chesapeake Bay	1
            Chesapeake Bay Program and Regional Focus Workgroup	1
C.     Purpose of this characterization	3
D.     Geographic focus of the characterization	5
E.     Other characterization efforts	6

II.     How were the characterizations determined?	...........	7

III.    What will be done with this characterization?	9

IV.    What are the results of the characterization?	.............	9

V.     References	.......................................	........49

VI.    Appendix A.....		...............A-l

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                            EXECUTIVE SUMMARY

       There are many types and sources of chemicals - both natural and manmade - in our
environment. For example, chemicals such as metals and pesticides are released into the
environment from natural processes and/or human activities.  Although many chemicals do not
pose a threat, certain types and levels of chemicals found in waterbodies have the ability to affect
the reproduction, development and, ultimately, the survival of living resources. By living
resources we mean the fish, shellfish, crabs, worms, grasses and other creatures. These
chemicals are called toxics or chemical contaminants.

       Chemical contamination in water, sediment and/or in animal tissue is an important issue
for people everywhere.  In the Chesapeake Bay region, scientists and managers have been
carrying out a multi-step effort to assess the Bay's tidal rivers and identify, or characterize, areas
that are either free of chemical contamination or show early warning signs of chemical
contamination. The result of that effort is this report:  Targeting Toxics: A Characterization
Report - A Tool for Directing Management & Monitoring Actions in the Chesapeake Bay's Tidal
Rivers. At the same time, scientists have been working to identify the sources of chemical
contamination in the Bay's tidal rivers. That study resulted in a related report:  the 1999
Chesapeake Bay Basinwide Toxics Loading and Release Inventory (TLRI). The information in
these reports will help Chesapeake Bay Program  decision makers target specific tidal rivers for
management and monitoring efforts.

Development of the Results
       It is important to note that this report is the Bay Program's first comprehensive attempt to
characterize the Bay's tidal rivers.  It  gives the most up-to-date picture possible based on
available data. The panel of experts who characterized the rivers, the Regional Focus
Workgroup of the Bay Program's Toxics Subcommittee, underwent an extensive three-year
effort to weigh all available chemical contaminant data for each river segment  and, based on their
best professional judgement, developed consensus on the final characterization.

       The Chesapeake Bay Program's Scientific and Technical Advisory Committee (STAC)
technically reviewed the technical workplan and the public report and provided a very favorable
and constructive review, indicating that this initial assessment of the Bay's tidal rivers "provides
a good model for other estuary programs to utilize" (See Appendix A for the STAC review and
the Toxics Subcommittee's response).

Top Findings
       Of the 38 river segments that the Bay program characterized for the report, there were no
new Regions of Concern. The report  supported previous conclusions about chemical
contaminant-related problems, including where they were suspected. The effort also highlighted
areas needing additional data. Overall, the Bay Program panel identified:
•      No New Regions of Concern  (hot spots) - Three areas were designated in 1993 and still
       remain. These are areas where available data indicate that there is a probable chemical
       contaminant-related problem.

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•      Eight Areas with Low Probability for Adverse Effects (clean bill of health/no known
       problems with chemical contamination) - These are areas where available data indicate
       that it is unlikely that there is a chemical contaminant-related problem.
•      10 Areas of Emphasis (early warning signs/areas where living resources may be
       affected by chemical contamination) - These are areas where available data indicate
       that there is a significant potential for a chemical contaminant-related problem.
•      20 Areas with Inconclusive or Insufficient Data - Available data are inconclusive or
       insufficient for characterizing the region into any of the three previous categories. Either
       the data are too limited temporally and/or spatially, do not provide a sufficient mix of
       concentration and effects data, are inconclusive or conflicting, or are not of good enough
       quality to characterize the region.  These regions will be given high priority for future
       characterization.

Human Health
       This report was designed to identify areas where chemical contaminant effects on the
Bay's living resources occur or have the potential to occur. Human health impacts from
contaminated air, soil and drinking water are not addressed. However, because potential human
health impacts are an important issue, state agencies have already looked at human health issues
in the tidal rivers of the Bay. Where human health concerns already have been identified,
appropriate fish consumption advisories or other warnings have been issued. This report should
not alter the current recreational or commercial uses of any of the rivers. If swimming, fishing
and boating are allowed now, they should continue.

Context of the Characterization Effort
       The Bay Program's Toxics Strategy calls for voluntary toxics reduction and prevention
actions that are consistent with, and supplement, the requirements under the Clean Water Act.
These Bay Program efforts build upon the ongoing state and federal regulatory programs to
ensure the protection of the Bay's living resources and human health. This characterization
report of the Bay's tidal rivers augments the state assessments of impaired waters required under
the Clean Water Act by identifying areas with potential contaminant problems, areas with no
known contaminant problems, and areas needing more data.  This report is a first cut at
characterizing the status of chemical contaminant effects on the living resources inhabiting the
Bay's tidal rivers.

       This report gives the most up-to-date picture possible based on available data; however,
there are specific limitations to what the report is and is not.

What the Characterization Report IS:
•      IS the most comprehensive characterization to date of the chemical contaminant-
       related problems that could affect living resources in the tidal rivers of the Bay.
       This characterization is more comprehensive than any other effort in the region. It goes
       beyond the state's  impaired waters lists by identifying the areas with early warning signs
       where living resources may be affected by chemical contamination (Areas of Emphasis),
       areas that do not have any known contamination problems (Areas with Low Probability

                                          iv

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      for Adverse Effects) and areas where the data are insufficient or inconclusive (Areas with
      Insufficient or Inconclusive Data). This report enhances the picture of the status of
      chemical contaminant-related problems in the Bay's tidal rivers.

•     IS a broad characterization of chemical contaminant conditions in the Chesapeake
      Bay's tidal rivers. The panel of experts who characterized the rivers weighed all
      available chemical contaminant and effects data for each river segment and, based on
      their best professional judgement, developed consensus on the final characterization. All
      of the available data evaluated had to convey a reasonably consistent record throughout
      an entire segment, describing the status of chemical contaminant effects on living
      resources, to make a characterization. If available data were spatially or temporally
      insufficient to represent the entire segment, or if data were conflicting or inconclusive in
      describing the entire segment, a segment was characterized as an Area with Insufficient or
      Inconclusive Data.  The characterization of a particular river segment does not mean that
      the entire area has a chemical contaminant-related problem because chemical
      contaminant conditions are not uniform throughout each segment.  For example, even in
      the Regions of Concern, there are areas that have no known problems. When more data
      are available, future efforts will characterize specific areas within a river segment.

•     IS a supporting document to assist the Bay Program in reevaluating and revising
      the 1994 Chesapeake Bay Basinwide Toxics Reduction and Prevention Strategy. The
      characterization report will be used to help formulate future goals to direct chemical
      contaminant reduction and prevention and to direct management and monitoring in the
      appropriate areas beyond the year 2000.

What the Characterization  Report IS NOT:

•     IS NOT a  barometer for measuring the potential impacts on human health. This
      report was designed to identify areas where chemical contaminant effects to the Bay's
      living resources occur or have the potential to occur. Human health impacts from
      contaminated air, soil and drinking water are not addressed. However, because potential
      human health impacts are an  important issue, state agencies have already looked at
      human health issues in  the tidal rivers of the Bay. Where human health concerns already
      have been identified, appropriate fish consumption advisories or other warnings have
      been issued. This report should not alter the current recreational or commercial uses of
      any of the rivers.  If swimming, fishing and boating are allowed now, they should
      continue.

•     IS NOT a  characterization  of the mainstem Bay or non-tidal rivers.  The mainstem
      Bay was not characterized because levels of chemical contaminants tend to be very low
      and effects are unlikely. Techniques for detecting effects at these low levels are under
      development.  Also, the report characterizes the tidal rivers of the Bay, as opposed to
      non-tidal waters, because tidal waters are the focus of the Bay Program's toxics efforts.
      The sites of many of the known toxics problems are in tidal waters, and most of the urban

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       areas and toxics-related land use activities are adjacent to tidal waters. However, it is
       important to note that non-tidal waters (above the fall line) are also a source of chemical
       contaminants to tidal waters.

•      IS NOT a ranking of the tidal rivers in the Bay based on chemical contamination.
       This report is not intended to determine which river has the highest chemical
       contamination relative to all others. The report was designed to classify the Bay's tidal
       rivers into one of four categories based on the severity of chemical contaminant-related
       problems and the resulting need for chemical contaminant reduction, prevention, and/or
       assessment actions.

•      IS NOT an inventory of the sources of chemical contamination. This report only
       identifies whether there is or is not chemical contamination in the Bay's tidal rivers. It
       does not indicate where the particular contaminants  are originating. The 1999 TLRI
       addresses the sources and amounts of chemical  contaminants into the Bay and rivers.  It
       also is part of the Bay Program's toxics reevaluation and revision effort.

How The Chesapeake Bay Program Will Use This Information
       Overall, the characterization report and the 1999 TLRI will serve as valuable planning
and targeting tools to assist the  Bay Program in assessing the success of its previous toxics
reduction and prevention goals, and to formulate new goals. More specifically, the Bay Program
is committed  to take the following actions based on the results of this characterization effort:
•      Identify and  implement  necessary pollution prevention actions in the Areas of Emphasis
       to eventually eliminate the potential for chemical contaminant-related impacts.
•      Take actions necessary to ensure future protection of the Areas of Low Probability for
       Adverse Effects.
•      Initiate necessary assessments  in Areas with Insufficient or Inconclusive Data to order to
       characterize these areas.
                                           VI

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     Segment-by-Segment Results for the Tidal Portions of the Bay's Rivers
      The segments are being listed north to south and east to west. They are not ranked.
3 Regions of Concern
 Patapsco River/Baltimore Harbor, MD
 Anacostia River, DC
 Elizabeth River, VA

10 Areas of Emphasis
 Middle River, MD
 Back River, MD
 Magothy River, MD
 Severn River, MD
 Patuxent River, MD (2 segments - Upper and Middle)
 Potomac River, MD (2 segments - Upper and Middle)
 Chester River, MD
 James River, VA (1 segment - Lower)

8 Areas with Low Probability for Adverse Effects
 Potomac River, MD (1 segment - Lower)
 Sassafras River, MD
. Nanticoke River, MD
 Tangier Sound, MD/VA
 Rappahannock River, VA (2 segments - Upper and Lower)
 York River, VA (2 segments - Lower and Upper Mobjack Bay)

20 Areas with Insufficient or Inconclusive Data
 Bush River, MD
 Gunpowder River, MD
 South/Rhode River, MD
 Patuxent River, MD (1 segment - Lower)
 Northeast River, MD
 Elk River/Bohemia River, MD
 Wye River/Miles River/Eastern Bay, MD
 Choptank River, MD (2 segments - Upper and Lower)
 Wicomico River, MD,
 Manokin River, MD
 Big Annemessex River, MD
 Pocomoke River, MD/VA
 Rappahannock River, VA (1 segment - Middle)
 Mattaponi River, VA
 Pamunkey River, VA
 York River, VA (2 segments - Upper and Lower Mobjack Bay)
 James River,  VA (2 segments - Upper and Middle)
Segment Profile
Page Number
page 25
page 12
page 22
page 40
pages 29 & 30
pages 33 & 34
page 15
page 21
page 35
page 39
page 26
page 42
pages 36 & 38
pages 46 & 47
page 14
page 18
page 41
page 31
page 27
page 17
page 44
page 16
page 43
page 23
page 13
page 32
page 37
page 24
page 28
pages 45 & 48
pages 19 & 20
                                        VII

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                    Status of Chemical  Contaminant Effects on  Living Resources
                                        in the Chesapeake Bay's Tidal Rivers
                                                                                             Northeasi River
                                                                              Chester River
                                                                              EactamBay
                                                                              Wye River
                                                                              Miles River
           CMdcrixxniny River	-.,
                
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I.     Why was this characterization conducted?

A.     Purpose of this report

       This report, Targeting Toxics: A Characterization Report - A Tool for Directing
Management & Monitoring Actions in the Chesapeake Bay's Tidal Rivers, is intended to provide
the public with a summary of the purpose and methods used to characterize the status of
chemical contaminant effects on the living resources inhabiting the Bay's tidal rivers, as well as
to discuss the results of each river's characterization. A more detailed description of the steps the
Chesapeake Bay Program took to develop the characterization is outlined in the Targeting
Toxics: A Characterization Report - A Tool for Directing Management & Monitoring Actions in
the Chesapeake Bay's Tidal Rivers - A Technical Workplan [1].

       The Chesapeake Bay Program's Scientific and Technical Advisory  Committee (STAC)
technically reviewed the technical workplan and this public report and provided a very favorable
and constructive review, indicating that this  initial assessment of the Bay's tidal rivers "provides
a good model for other estuary programs to utilize" (See Appendix A for the STAC review and
the Toxics Subcommittee's response).

B.     Background information

Toxics and the Chesapeake Bay
       Chemicals in the sediment, fish tissue and water that have the ability to affect the
reproduction, development, and, ultimately,  survival of living resources have been referred to as
toxic chemicals, or chemical contaminants.  Scientists have pointed out that any large body of
water will never be completely free of chemical contaminants. In fact, many chemicals,
including zinc, copper and other metals, occur naturally in the Bay and its sediments.

       Chemical contaminants entering the Bay and its tidal rivers come from natural processes
(such as weathering of rock) and human activities (such as manufacturing and driving). Many
problem chemicals are currently being loaded into the Bay's rivers from  a variety of sources,
such as pesticide usage, urban activities, industrial activities, and shipping and boating activities.
Chemicals travel through the watershed and are eventually deposited in the Bay or rivers.  For
example, oil and grease from a parking lot can be washed down a drain by stormwater and into a
stream, eventually leading to the Bay.  Some chemicals reach harmful levels when they
accumulate in the sediment at the bottom of the Bay, in animal tissue, and/or in the water
column.

Chesapeake Bay Program and Regional Focus Workgroup
       The Bay Program is a unique regional partnership that has been leading and directing the
restoration of the Bay since 1983. The Chesapeake Executive Council, consisting of the
governors of Maryland, Pennsylvania, and Virginia; the mayor of Washington, D.C.; the EPA
administrator; and the chair of the Chesapeake Bay Commission, is the Bay Program's governing

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body and guides Bay restoration with directives and policies.  The Bay Program is divided into
subcommittees to address numerous Bay issues. One of the subcommittees, the Toxics
Subcommittee, handles all chemical contaminant issues in the Bay watershed.

       Since the  1980s, Bay scientists have agreed that the nature, extent and severity of toxic
impacts vary widely throughout the Bay system. Based on further research, scientists determined
that there was no evidence of severe, system-wide chemical contaminant problems in the Bay or
its tidal rivers. However, three localized problem areas, or "hot spots," were discovered.  In
1993, the Executive Council designated these hots spots as Regions of Concern:  the Anacostia
River (DC), the Baltimore Harbor/Patapsco River (MD), and the Elizabeth River (VA). These
three specific areas were targeted for intense management efforts by Bay Program partners
because notable chemical contaminant problems were well documented and living resources
exhibited chemical contaminant-related effects. The Executive Council directed the jurisdictions
to work with stakeholders to develop Regional Action Plans to remediate (clean up), reduce, and
prevent chemical contamination in these chemical contaminant hot spots.

       The Executive Council realized the importance  of characterizing the chemical
contaminant conditions in tidal tributaries outside these Regions of Concern to provide additional
information about chemical contamination to the public, managers, and scientists. In the 1994
Chesapeake Bay Basinwide Toxics Reduction and Prevention Strategy, the Executive Council
committed the Bay Program signatories to:

       "...evaluate available data through the Chesapeake Bay Regions of Concern
       identification protocol, determine whether additional Regions of
       Concern should be designated, and publish a revised characterization of Bay
       and tidal tributary habitat status with regard to evidence for the presence of
       chemical contaminant-related impacts. Every three years this same evaluation
       of data will be conducted using data collected since the previous evaluation [2]."

       In  1995, the Toxics Subcommittee formed the Regional Focus Workgroup to characterize
the status of chemical contaminant effects on the living resources inhabiting the Bay's tidal
rivers. The workgroup represents a good balance of technical experts from state agencies, federal
agencies, interstate commissions, research institutions;  and industries. Workgroup members
weighed all available chemical contaminant data for each river segment and, based on their best
professional judgement, developed consensus on the final characterization. The strength of this
report is represented by the workgroup's technical knowledge of chemical contaminant data, its
diversity of interests and membership, and its ability to reach a consensus on the final
characterization.

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         What has the Bay Program been doing to reduce chemical contamination
                            in the Chesapeake Bay and its rivers?
  The Bay Program has been working to reduce chemical contamination in the Bay since 1983 with the Executive
  Council's signing of the historic Chesapeake Bay Agreement. In 1994, the Council adopted the 1994
  Chesapeake Bay Basinwide Toxics Reduction and Prevention Strategy. The goal of the strategy is "...a
  Chesapeake Bay free of toxics by reducing or eliminating the input of chemical contaminants from all
  controllable sources to levels that result in no toxic or bioaccumulative impact on living resources that inhabit
  the Bay or on human health." The 1994 strategy called for a regional focus to address chemical contaminant
  problem areas, a focus in chemical contaminant assessments in direct support of management actions, and an
  increased emphasis on pollution prevention. As a result of this toxics strategy, Bay Program chemical
  contamination reduction efforts have focused on:
  •       Controlling chemical contaminants in areas of known chemical contamination. The three Regions
         of Concern (areas with known chemical contamination) have developed Regional Action Plans to
         reduce, remediate and prevent future chemical contamination.
  •       Reducing chemical contamination entering the Bay.  These efforts have focused on determining
         contaminant sources as identified in the Toxics Loading and Release Inventory, reducing pesticide use
         through Integrated Pest Management practices, and preventing pollution from point and nonpoint
         sources.
  •       Quantifying the chemical contamination in the Bay's tidal rivers. This effort provides a
         characterization of the chemical contaminant-related problems that could affect living resources in the
         tidal rivers of the Bay. This comprehensive characterization identifies areas with chemical
         contaminant-related problem areas, areas with no known chemical contaminant problems and areas
         needing more data.

  More information about any of these programs can be obtained by calling the Chesapeake Bay Program Office
  atl-800-YOURBAY.
C.     Purpose of this characterization

       This characterization represents the Bay Program's first comprehensive analysis of
available data to assess the status of chemical contaminant effects on living resources in the
Bay's tidal rivers.  This characterization goes beyond identifying areas with known chemical
contamination to identifying areas where significant potential exists for chemical contaminant-
related impacts on living resources and their habitats. This effort also identifies areas that do not
show evidence of adverse impacts due to chemical contamination and areas where data are
lacking and additional study is required.

       This report identifies areas where chemical contaminant effects to the Bay's living
resources occur or have the potential to occur. Human health impacts from contaminated air,
soils, and drinking water are not addressed.  State agencies have already looked at human health
issues in the tidal rivers and where human health concerns already have been identified,
appropriate fish consumption advisories or other warnings have been issued by the respective
state/district.  This report should not alter the current recreational or commercial uses of any of
the rivers segments.  If swimming, fishing and boating are allowed now, they should continue.

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       Based on all available chemical contaminant data, the workgroup characterized all tidal
river segments of the Bay into one of four categories:
 Region of Concern - Available data indicate that there is a probable chemical contaminant-
 related problem. Concentrations of chemical contaminants are above thresholds associated
 with adverse effects, and these chemicals appear to be causing toxic effects on living
 resources.

 Area of Emphasis - Available data indicate that there is significant potential for a chemical
 contaminant-related problem. Data reveal either elevated concentrations of chemical
 contaminants above thresholds associated with adverse effects and/or chemical contaminant-
 related adverse effects on living resources, but limited or no evidence for a relationship
 between the measured chemical levels and observed effects exists.

 Area with Low Probability for Adverse Effects - Available data indicate that it is unlikely that
 there is a chemical contaminant-related problem in the region. Data reveal measured chemical
 contaminant concentrations below thresholds associated with  adverse effects and no observed
 chemical contaminant-related adverse effects on living resources.

 Area with Insufficient or Inconclusive Data - Available data are insufficient for characterizing
 the region into any of the three previous categories. Either the data are too limited temporally
 and/or spatially, do not provide a sufficient mix of concentration and effects data, are
 inconclusive or conflicting, or are of unknown quality and cannot support the level of
 confidence required to characterize the region. These regions will be given high priority for
 future characterization.
       Characterizing the tidal rivers into these categories has management and political
ramifications. In the 1994 toxics strategy, the Bay Program signatories committed to take the
following actions based on the results of this characterization:

•      Develop, adopt, and begin implementation of Regional Action Plans within two years of
       designation of additional Regions of Concern;
•      Identify and implement necessary pollution prevention actions in the identified Areas of
       Emphasis to eventually eliminate the potential for chemical contaminant-related impacts;
•      Take actions necessary to ensure future protection of resources in Areas with Low
       Probability for Adverse Effects; and
•      Initiate necessary assessments in Areas with Insufficient or Inconclusive Data to
       characterize the habitat status through the protocol.

       The Executive Council committed the Bay Program signatories to reevaluate and revise,
as necessary, the basinwide toxics strategy by 1999. This characterization report is part of the
overall strategy reevaluation and revision effort and will serve as a valuable tool to help the Bay

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Program formulate future goals for beyond the year 2000.  In reevaluating and revising the 1994
toxics strategy, the Bay Program will use this information to identify the link between sources
(as identified in the Bay Program's 1999 Chesapeake Bay Basinwide Toxics Loading and
Release Inventory) and the Bay/river chemical contaminant conditions to target specific sources
and chemicals to reduce.

       Characterizing the tidal rivers of the Bay also has an educational and outreach focus.
Information on impacts and chemicals causing impacts, coupled with the updated 1999
Chesapeake Bay Basinwide Toxics Loading and Release Inventory (TLRI) and available land use
data, will enable managers, scientists, and the public to target their toxics reduction and
prevention activities toward specific sources and chemicals in impacted areas of the Bay.
Resource managers may find the characterization of their jurisdictional waters insightful for
formulating site-specific or contaminant-specific action plans.  Scientists may use this
characterization to target specific areas for additional assessment to better characterize chemical
contaminants conditions. The public, community groups, and watershed associations can
augment the Bay Program's activities by helping to develop and implement a targeted response
to contaminant problems on a local watershed scale.  They can use this information about the
tidal rivers with estimates of loadings to help
clean up local waters and/or protect them
from potential contamination. Stakeholder
action has worked well in the Elizabeth
River, a Region of Concern, with the creation
of the Elizabeth River Project (see inset).
This successful stakeholder organization
could serve as a model for the development
of additional community stakeholder groups.
For additional information on activities to
reduce chemical contamination, please refer
to Section III.
Elizabeth River Project
The Elizabeth River Project was founded in 1992 to
build broad community involvement in restoring the
environmental health of the Elizabeth River, a Region
of Concern. This partnership includes businesses,
educators, military and government representatives.
In order to improve the conditions in the Elizabeth
River, the Elizabeth River Project's Watershed Action
Team developed and implemented a detailed
Watershed Action Plan which outlines specific
guidelines to combat the river's degraded status.
D.     Geographic focus of the characterization

       The Chesapeake Bay has a direct connection with the Atlantic Ocean.  Because of the
ocean tides, saltwater from the Atlantic is mixed in the Bay with freshwater derived from land
runoff.  The part of the Bay and its rivers that are influenced by the tide are referred to as the
"tidal Bay" and "tidal rivers." Moving upstream, there comes a point at which the rivers are no
longer influenced by the ocean tide.  The portions of the rivers that are not under the influence of
the tide are referred to as "non-tidal." The boundary between the non-tidal and tidal portions of a
river is called the "fall line." The fall line is the physiographic boundary representing the natural
geographic break between the non-tidal and tidal regions of the Bay watershed.  On the western
shore, Interstate 95 generally follows the path of the fall line.

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        Chemical contaminants entering the tidal rivers tend to get trapped in the rivers with only
a small amount making it to the mainstem of the Bay [3]. The mainstem Bay was not
characterized because levels of chemical contaminants tend to be very low and effects are
unlikely. Techniques for detecting effects at these low levels are under development. The
workgroup characterized the Bay's tidal rivers, as opposed to non-tidal rivers, because tidal
waters are the focus of the Bay Program's chemical contaminant efforts. In addition, non-tidal
waters were not targeted because the sites of many of the known toxics problems are in tidal
waters, and most of the urban areas and toxics-related land use activities are adjacent to tidal
waters. However, it is important to note that non-tidal waters  — above the fall line ~ are also
sources of chemical contamination.  All waters in Pennsylvania are non-tidal; therefore, the
workgroup did not characterize these rivers.

       The Bay Program divided the Bay and its tidal rivers into a number of geographical
segments for the purpose of identifying areas in the Bay with similar attributes for collecting,
analyzing, and reporting data.  The workgroup used this segmentation scheme to characterize 38
tidal river segments.  Most of the western shore tidal rivers are divided  into 3  segments, while
most of the eastern shore rivers and the smaller western shore  rivers are represented by one
segment. Some segments may comprise more than one river.  The characterization worked well
at this spatial scale given the amount of data available. Also, this scale is appropriate for
stakeholder groups who are often organized around a river or watershed.

       The three Regions of Concern designated by the Executive Council in 1993 were not re-
characterized because current chemical contaminant data support the previous characterizations.
E.
Other characterization efforts
       There are several characterization efforts that identify chemical contaminant-related
problems in the Bay watershed. National efforts such as the Environmental Protection Agency
(EPA) Environmental Monitoring and Assessment Program and National Oceanic and
Atmospheric Administration's ongoing sediment characterization effort in the Bay are designed
to compare estuarine and coastal conditions on a nationwide scale. The national datasets used in
these efforts also were used in the Bay Program's characterization.

       There are also several regional programs that characterize chemical contamination in the
Bay's rivers.  Each state/district is required by section 303(d) of the Clean Water Act to develop
a list of impaired waterbodies that do not meet their designated uses, such as aquatic life use
(including fish/shellfish consumption), recreational use (swimming and boating), and  use as a
public water supply. The 303(d) list helps focus regulatory efforts to reduce chemical
contaminant impacts on living resources by reducing chemical contaminant loads into the Bay's
rivers. The Bay Program's characterization goes beyond the Clean Water Act requirements and
not only identifies chemical contaminant-related problem areas, but also identifies areas with
potential chemical contaminant problems, areas with no observable chemical contaminant
problems, and areas needing more data to assess chemical contamination problems. Such a

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comprehensive characterization is essential to better target management actions (e.g., voluntary
pollution prevention activities) in those areas with known chemical contaminants problems and
target more assessments in areas with limited chemical contaminant information. Together, these
efforts give the most complete, up-to-date picture possible based on the best available data.

       The Bay Program strived to be as consistent as possible with the state/district 303(d)
assessments, recognizing differences that may occur with the use of additional data and
interpretative tools. The state/district impaired waterbody designations are mainly based on
exceedences of EPA-approved water quality criteria and fish consumption advisories, with
supporting evidence from any available sediment and biological data (e.g., assessments of
benthic community in the sediment).  Due to the regulatory nature of the 303(d) lists, sediment
and biological data oftentimes do not serve as the sole basis for these characterizations, since
there are no  EPA-approved criteria. In this characterization, all available chemical contaminant
and biological data were evaluated, using the best interpretative tools available, to characterize
the probability of adverse effects on living resources due to chemical contamination in the Bay's
tidal rivers.  Maryland and Virginia state agency representatives were members of the workgroup
and ensured coordination with the state 303 (d) efforts.

II.    How were the characterizations determined?

       Before a final characterization of the Bay's tidal rivers could be developed, all available
chemical contaminant and biological data were acquired.  Due to the generally high cost of
chemical contaminant assessments, the Bay Program relies heavily on data collected by
federal/state agencies and research institutions in addition to Bay Program-funded assessments to
use in targeting its chemical contaminant management and monitoring activities.

       Two types of data were used in this characterization: chemical contaminant concentration
and effects data.  Most of the available data were contaminant concentration data (particularly
sediment data) with very limited effects data.

Concentration data
       Concentrations of chemical contaminants can be measured in the water column, the
sediment, and in finfish or shellfish tissue.  Living resources are exposed to these contaminant
levels in their habitat.

       Contaminant concentration data were compared to thresholds specified by the workgroup
in order to determine whether or not the chemical contaminant data presented a threat to exposed
living resources. A threshold is a chemical concentration level above which harmful effects on
living resources are suspected to occur if the exposure to that chemical concentration is
sufficient. Comparing available measured concentrations to chemical concentration thresholds is
necessary because it is difficult to know with certainty when concentration data are responsible
for harmful effects on the Bay's living resources.

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Effects data
       Laboratory toxicity data and benthic community data were considered "effects" data
because they indicate the measurable effect chemical contaminants have on living resources. For
example, the toxicity of a river's sediment and water can be determined by exposing sensitive
Bay species to water and sediment samples in a laboratory and observing the chemical
contaminant impacts (e.g., mortality, reduction in growth and reproduction, etc.).  Chemical
contaminant effects also can be measured in the rivers by directly assessing the effect of
chemical contaminants on living resources inhabiting the rivers, such as benthic communities
living in the sediment.

Characterization process
       Finally, workgroup members weighed all available chemical contaminant data for each
river segment and, based on their best professional judgement, developed consensus on the final
characterizations. Many different factors were considered when reviewing the available data and
making the characterizations, such as the quality of the data, the spatial and temporal distribution
of the data, the frequency of elevated levels of chemical contaminants, and the correlation
between  elevated levels and effects on living resources. To make a characterization, all of the
available data evaluated by the workgroup had to be reasonably consistent throughout an entire
segment, describing the status of chemical contaminant effects on living resources. If data were
spatially or temporally insufficient to represent the entire segment, or if data were conflicting or
inconclusive in describing the entire segment, the workgroup characterized the segment as an
•Area with Insufficient or Inconclusive Data.  The strength of this characterization is represented
by the workgroup's technical knowledge of chemical contaminant data, its diversity of interests
and membership, and its ability to discuss the data and reach a consensus on all segment
characterizations.

       As called for in the 1994 toxics strategy, the Bay Program signatories have committed to
update this characterization every three years based on data collected since the previous
evaluation. Triennial updates to the characterization will allow the Bay Program to assess
progress  in reducing the number of Regions of Concern and Areas of Emphasis, increasing the
number of Areas with Low Probability for Adverse Effects, and eliminating all Areas with
Insufficient or Inconclusive Data.

Limitations of Data
       It is important to note that, to date, there is no Baywide monitoring program designed to
characterize toxics conditions in the Chesapeake Bay's tidal rivers on the scale necessary to
perform comparable assessments of all rivers. Information used for this characterization was
collected for a wide variety of studies that were conducted for different purposes.  The result of
this collection is a dataset with uncoordinated and incomplete spatial and temporal coverage.
The workgroup was faced with the challenge of piecing together these different datasets and
developing a consistent set of decision rules for how to interpret this information in making a
characterization. As such, this characterization has limitations in the level of detail at which it
can characterize toxic effects on the Bay's living resources.  Through increased funding,
intensified coordination with federal and state toxics monitoring and research efforts, and
intentional collaboration between Bay Program signatory  states at the governmental and
academic level to address Bay-wide issues, the gaps in data coverage will be filled.
                                           8

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III.   What will be done with this characterization?
       The primary value and utility of the characterization is in identifying areas that need
additional monitoring and assessment to better characterize the status of toxic effects on living
resources inhabiting those areas. This characterization can also serve as a planning tool to help
the Chesapeake Bay Program determine the areas in which to focus its voluntary pollution
prevention and reduction efforts and the areas in which to focus its voluntary
preservation/conservation efforts. The characterization gives the State/District partners base
information to allow them to conduct the more detailed risk assessment analysis, site specific
analysis, and source assessment studies which may be necessary before regulatory actions can be
taken. The Bay Program will use this characterization to help focus management and monitoring
activities and reduce chemical contamination in the Bay's tidal rivers, but the public can
supplement governmental efforts and provide valuable assistance in the restoration and
protection of the Bay. The public can use this characterization by:

•      taking action to reduce or eliminate chemical contaminants that enter the Bay and its tidal
       rivers by informing private citizens, industries, municipalities, military facilities, and
       state/local governments about a local river's characterization and the loadings into local
       waterbodies;
•      calling attention to the lack of data or chemical contaminant conditions in local rivers and
       informing the Bay Program about ongoing local research studies;
•      developing local watershed groups to call for better management of chemical
       contaminant problems in the public's waters;
•      attending technical assistance workshops and public forums to learn more about chemical
       contaminant-related problems; and
•      implementing pollution prevention in their communities to protect areas with a  clean bill
       of health.

       This characterization provides unique information about chemical  contamination in the
Bay's tidal rivers.

       In the future, the Bay Program will strive to expand its chemical contaminant data,
improve its interpretive tools,  and improve its understanding of chemical contamination in the
Bay's rivers to enhance this characterization.

IV.   What are the results of the characterization ?

Segment Profiles

       The following segment profiles represent a summary of each segment characterization,
including a brief justification of the characterization, the available data considered, and any
caveats or limitations of the characterization. Where necessary, a section has been included on
"caveats/limitations" of the characterization which indicates the workgroup's level of confidence
in the characterization.  Also included for each segment are additional assessments of each river

-------
conducted by Maryland and Virginia as directed by the Clean Water Act. These assessments list
any "water quality limited segments" (areas that are "impaired" or "threatened" by chemical
contaminants) and any waters with fish consumption advisories.  Together, the Bay Program
characterization and the state assessments provide the most complete picture to date on chemical
contamination in the Bay's tidal rivers based on the best available data.

       It is important to note that areas identified by the states' assessments do not necessarily
correspond to the segment characterizations because the purposes of the characterization and the
state assessments are different.  The purpose of the Bay Program characterization is to provide a
status of chemical contaminant effects on the living resources inhabiting the Bay's tidal rivers.
This characterization will serve as a planning tool to help target future monitoring and voluntary
chemical contaminant reduction and prevention activities. The states' assessments are mandated
by the Clean Water Act and serve as a regulatory tool for reducing loads of contaminants to
impaired waters. Because of the regulatory nature of the states' assessments, the states place
more weight on data that indicate levels of chemical contaminants that exceed EPA-approved
thresholds, such as the EPA water quality criteria or State Water Quality Standards.

       Overall, good spatial and temporal coverage of chemical contaminant concentration and
effects data are lacking. If data were spatially or temporally insufficient to represent the entire
segment, or if data were conflicting or inconclusive, the workgroup characterized the segment as
an Area with Insufficient or Inconclusive Data. In most cases, more effects data (i.e., sediment
and water toxicity tests and benthic community assessments) are needed to  confirm initial
characterizations or to make characterizations for those segments with insufficient or
inconclusive data.

       These profiles summarize evidence about adverse effects to living resources and the
chemical contaminants that are likely causing the effects. Examples of contaminants that may
cause effects are metals (such as copper, lead, mercury) and organic contaminants such as
polynuclear aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). Metals come
from both point and nonpoint sources from a variety of activities, PAHs come from the
combustion of fossil fuels and from oil and grease used in cars. PCBs were used as fire
retardants and can be found in older electric transformers and other machinery. Although PCBs
and some pesticides are banned, they are still found in the environment. For information about
the sources and loads of chemical contaminants entering the Bay and its tidal rivers, please refer
to the 1999 Chesapeake Bay Basinwide Toxics Loading and Release Inventory (TLRI) [3].  As
previously stated, this characterization provides the status of chemical contaminant effects on
living resources. Coupled with the updated TLRI, this characterization will enable Bay Program
managers to target their chemical contaminant reduction and prevention activities toward specific
sources and chemicals in impacted areas.  For information about how the Bay Program will use
this information, see the Executive Summary of this report.
                                           10

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For More Information...

•      For more information about the datasets used to support these characterizations, please
       refer to the technical workplan [1].
•      For electronic copies of the data evaluated by the workgroup, please refer to the Bay
       Program Home Page at http://www.chesapeakebay.net or contact the Bay Program Office
       at 1-800 YOUR BAY.  Note that where feasible, links are made to the actual datasets or
       summary reports/abstracts.
•      For a copy of the 1999 Chesapeake Bay Basinwide Toxics Loading and Release
       Inventory, call the Bay Program Office at 1-800 YOUR BAY.
•      For more information on Maryland's assessment of impaired waterbodies and fish
       consumption advisories, please refer to the Maryland Department of the Environment
       Home Page at http://www.mde.state.md.us.
•      For more information on Virginia's assessment of impaired and threatened waterbodies,
       please refer to Virginia Department of Environmental Quality at
       http://www.deq.state.va.us.
•      For more information on Virginia's fish consumption advisories, please refer to the
       Virginia Department of Health at http://www.vdh.state.va.us.
                                                        U.S. EPA Headquarters Library
                                                              Mail code 3201
                                                        1200 Pennsylvania Avenue NW
                                                          Washington  DC 20460
                                         11

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Tidal Back River, Maryland
Area of Emphasis
   Region of Concern

   Area ot Emphasis

   Low Probability
   for Adverse Effects
   Insufficient Data
  AddttionilStjt*
   Afsisimtnts


£  Fsh Advisories
•  Impiired Witeri

B  Thfeit«n«d Wjt«rs
                                                              Summary: The tidal Back
                                                              River was characterized as
                                                              an Area of Emphasis
                                                              because metals and
                                                              polychlorinated biphenyls
                                                              (PCBs) found throughout
                                                              the river in sediment were at
                                                              levels that indicate probable
                                                              adverse effects on living
                                                              resources. Additionally,
                                                              there is an existing fish
                                                              consumption advisory for
                                                              eels and catfish due to
                                                              chlordane contamination.
                                                              Results and Justification:
                                                              The available data
considered in making this characterization were chemical contaminant concentration data for
sediment, effects data (sediment toxicity tests), and information on an existing fish consumption
advisory in the river. The spatial coverage of the recent sediment contaminant concentration data
was excellent and indicated a widespread distribution of metals, such as zinc and nickel (and in
some areas, lead, mercury, and chromium), and PCBs at elevated levels that could cause adverse
effects on the Bay's living resources. Only one out of four sediment samples taken from
different areas of the Back River was found to be toxic to Bay organisms when exposed to the
sediment in the laboratory.  However, widespread, consistently elevated levels of metals and
PCBs in the sediment, coupled with the existing fish consumption advisory in the Back River,
was sufficient evidence of the potential for adverse effects in this river.

Additional State Assessments: In 1998, in assessing the conditions of its waters as directed by
the Clean Water Act, Maryland designated this area as a chemical contaminant-impaired
waterbody and placed it on a priority list of waters to manage. Currently, there is an advisory for
the consumption of eels and catfish from Back river due to the presence of chlordane in the tissue
of these fish.
                                           12

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Big Annemessex River, Maryland
Area with Insufficient or Inconclusive Data
                                                             Summary:  The Big
                                                             Annemessex was
                                                             characterized as an Area with
                                                             Insufficient or Inconclusive
                                                             Data because data were
                                                             temporally and spatially,
                                                             insufficient to describe the
                                                             conditions in the river.

                                                             Results and Justification:
                                                             The available data considered
                                                             in making this characterization
                                                             were chemical contaminant
                                                             concentration data for
                                                             sediment and effects data
(benthic community assessments).  The spatially limited sediment chemical contaminant
concentration data did not indicated chemical contaminant levels that would cause probable
adverse effects on living resources. However, benthic communities were degraded at two out of
the four areas sampled, with the cause unknown. Additional assessments in this river are needed
to describe the condition of the river.

Additional State Assessments: In 1998, in assessing the conditions of its waters as directed by
the Clean Water Act, Maryland did not designate the river as impaired by chemical
contamination.
 Region of Concern

 Area of Emphasis

 Low Probability
 for Adverse Bfeots
 Insufficient Data
AdditionilStite
 Asscsxmtntf

 Fih Adviforit*
 Impjirid Wjttrs
 Threjttntd Wtters
                                            13

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Tidal Bush River, Maryland
Area with Insufficient or Inconclusive Data
                                           Region of Concern

                                           Area of Emphasis

                                           Low Probability
                                           for Advene Effects

                                           Insufficient Data
                                          Add ilia n«l Stjte
                                           Ass ess merit*

                                        •  Fish Advisories
                                        •  impjiitd Wittis
                                        a  ThrtJtintd Wjlera
Summary:  The tidal Bush
River was characterized as an
Area with Insufficient or
Inconclusive Data because
data were insufficient to
describe conditions in the
river.  The spatial coverage of
the sediment chemical
contaminant concentration
data was very poor and there
was no available water or fish
tissue chemical contaminant
concentration data or effects
data.
Results and Justification: The only data available for this river were sediment chemical
contaminant concentration data which were spatially insufficient for describing the entire river.
The Aberdeen Proving Ground is in the process of submitting electronic data to the Bay Program
from a recently conducted ecological risk assessment of the Bush River.  Therefore, this river has
been initially characterized as an Area -with Insufficient or Inconclusive Data until the new data
are available and analyzed for future updates to the characterization.

Additional State Assessments: In 1998, in assessing the conditions of its waters as directed by
the Clean Water Act, Maryland did not designate the river as impaired by chemical
contamination.
                                            14

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Chester River, Maryland
Area of Emphasis, with the need for additional data to confirm characterization
                                              Region of Concern

                                              Area of Emphasis

                                              Low Probability
                                              for Adverse Effects
                                              Insufficient Data
                                             AddiifcnjIStite
                                              Assessments


                                              Ffeh Adviloiief
                                              Impaired Wjtin

                                              ThiMttntd Waters
                                                                 Summary: The Chester River
                                                                 was characterized as an Area of
                                                                 Emphasis because available
                                                                 water and sediment toxicity data
                                                                 and the elevated levels of a few
                                                                 pesticides and metals in some
                                                                 areas of the river indicated the
                                                                 potential for adverse effects on
                                                                 living resources.

                                                                 Results and Justification: The
                                                                 available data considered in
                                                                 making this characterization
                                                                 were chemical contaminant
                                                                 concentration data for water,
                                                                 sediment, and fish tissue and
effects data (water/sediment toxicity tests and benthic community assessments).  The sediment in the
upper portions of the Chester River was found to cause adverse effects on Chesapeake Bay organisms
exposed to it in the laboratory. Two banned pesticides, Dieldrin and DDT, were found in these
sediments and may have contributed to some of the biological effects observed. Metal toxicity is
unlikely. The ambient water was also found to cause adverse effects on Chesapeake Bay organisms
exposed to it. In laboratory studies, sediment from the upper reach of the Chester River was more toxic
to animals that live in the sediments than most other sediments tested in the Bay (ranking seventh out of
46 stations sampled in 16 rivers Baywide). Water from another station in the upper reach of the Chester
River was more toxic to animals that live in the water than most other water samples tested in the Bay
(also ranking seventh out of 46 stations sampled Baywide). DDT in the upper portion of the river and
lindane, arsenic, and nickel in the lower portion of the river were at levels in the sediment that indicate
adverse effects on living resources. Fish tissue data were too old to be representative of current
conditions. Although elevated levels of contaminants in the sediment were not pervasive and effects data
were lacking in the lower portion of the river, the elevated sediment contaminant levels and the observed
water and sediment toxicity data provided sufficient evidence of the potential for adverse effects in this
river.

Caveats/Limitations: Several workgroup members favored characterizing the Chester River as an Area
with Insufficient or Inconclusive Data based on what they perceived as inconclusive chemical
contaminant concentration and effects data.  The characterization of this river was driven largely by the
observance of water and sediment toxicity at sites in the upper and middle portions of the river.
However, for the most part, measured contaminants at these sites were below probable effects levels.
Data for the lower reaches were dated and toxicity information was lacking. The benthic community
data, which was fairly extensive both spatially and  temporally, suggested the presence of healthy
indigenous populations in more  than half of the sites sampled. The degraded benthic  communities
appeared to be related to low dissolved oxygen levels. Future assessments of both chemical contaminant
concentration and effects data are recommended to confirm this initial characterization.

Additional State Assessments: In 1998, in assessing the conditions of its waters as directed by the
Clean Water Act, Maryland did  not designate this segment as impaired by chemical contaminants. Based
on the data evaluated by the state, there was no evidence of a water quality  standards violation.
Furthermore, the Bay Program characterization considered additional data that were not included  in the
state's analysis. Future state efforts will consider additional data, as it becomes available.
                                               15

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Upper and Lower Choptank River, Maryland
Area with Insufficient or Inconclusive Data
                                       ^| Region of Concern

                                       {QQ Area o< Emphasis

                                       CS Low Probability
                                       *"" for Adverse Effects
                                       FTil Insufficient Data
                                         Additional Stjte
                                          Ass ess mints

                                       •   Fish Advisories
                                       •   Impjircd Vtfjttn
                                       Q   Thrcjttrxd Wjt«n
Summary:  The Choptank
River (both upper and lower
segments) was characterized
an Area with Insufficient or
Inconclusive Data because the
available sediment chemical
contaminant concentration data
were insufficient temporally
and spatially, and the fish
tissue chemical contaminant
concentration data were too
old to represent current
conditions. No water chemical
contaminant concentration or
toxicity effects data were
available.
Results and Justification: The available data considered in making this characterization were
chemical contaminant concentration data for sediment and fish tissue and effects data (benthic
community assessments).  Although sediment data were insufficient to describe the entire river,
the levels indicated a low probability of adverse effects on living resources.  Benthic community
data were inconclusive, since the main cause of degraded communities is likely low dissolved
oxygen levels. Water and sediment chemical contaminant concentration, water and sediment
toxicity tests, and benthic and fish community assessments were conducted on the Choptank in
1998 through a Bay Program funded study.  Once these data are available, they will be used to
update this characterization.

Additional State Assessments: In 1998, in assessing the conditions of its waters as directed by
the Clean Water Act, Maryland did not designate the river as impaired by chemical
contamination.
                                            16

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Elk and Bohemia Rivers, Maryland
Area with Insufficient or Inconclusive Data, with a potential metals contamination problem in
the sediment.
                                          Region of Concern

                                          Area of Emphasis

                                          low Probability
                                          for Adverse Effects
                                          ^sufficient Data
                                         Additioru! Slit*
                                          Assessments


                                       •  Fiti Advisories

                                       •  Impjii«d Waters

                                       D  Threatened Wit«rs
Summary:  The Elk and
Bohemia Rivers segment was
characterized as an Area with
Insufficient or Inconclusive
Data because the data were
insufficient to describe the
conditions of the segment.
The available sediment data
were too limited spatially and
temporally, water data were
too old, and benthic data were
too limited spatially to
adequately describe the entire
segment.
Results and Justification: The available data considered in making this characterization were
chemical contaminant concentration data for sediment and water and effects data (benthic
community assessments).  Although the data were too limited for describing the entire segment,
there was evidence for the potential for adverse effects on living resources. The available
sediment data indicated metals such as lead, silver, copper, cadmium, arsenic, zinc, and nickel at
levels well above those indicative of causing adverse effects on living resources.  Older water
data also showed elevated levels of copper and nickel. Furthermore, benthic communities were
degraded in several areas of this segment where low dissolved oxygen levels do not appear to be
the cause. Further assessments in this segment will help to confirm this suspected metals
contamination problem.

Additional State Assessments: In 1998, in assessing the conditions of its waters as directed by
the Clean Water Act, Maryland designated a section of the Elk River as a chemical contaminant-
impaired waterbody and placed it on a priority list of waters to manage. In May 1999, a fish
consumption advisory was issued in the C&D Canal for no consumption of all finfish species due
to PCBs. This information will be considered in making a future characterization of this segment
once all available data have been acquired.
                                           17

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Tidal Gunpowder River, Maryland
Area with Insufficient or Inconclusive Data
                                            Region of Concern

                                            Area of Emphasis

                                            Low Probability
                                            for Adverse Effects
                                            Insufficient Data
                                           Additional State .
                                           Assessments

                                        •  Fish Advisories
                                        •  Impaired Witers
                                        B  Threatened Waters
Summary':  The tidal
Gunpowder River was
characterized as an Area
with Insufficient or
Inconclusive Data because
the data were insufficient to
describe the segment. The
spatial coverage of the
sediment chemical
contaminant concentration
data was very poor, and
there were no available
ambient water or fish tissue
chemical contaminant
concentration data or
effects data.
Results and Justification: The only data available for this river were sediment chemical
contaminant concentration data which were spatially insufficient for describing the entire river.
The Aberdeen Proving Ground is in the process of submitting electronic data to the Bay Program
from a recently conducted ecological risk assessment of the Gunpowder River. Therefore, this
river has been initially characterized as an Area with Insufficient or Inconclusive Data until the
new data are available and analyzed for future updates to the characterization.

Caveats/Limitations: Future assessments of effects in this river will be helpful in confirming
this initial characterization.

Additional State Assessments: In 1998, in assessing the conditions of its waters as directed by
the Clean Water Act, Maryland designated a section in the upper portion of the river as a
chemical contaminant-impaired waterbody by heavy metals and placed it on a priority list of
waters to manage. This information will be considered by the Bay Program in making a future
characterization of this area once all available  data have been acquired.
                                            18

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Upper Tidal James River, Virginia
Area with Insufficient or Inconclusive Data, with some evidence of a potential contaminant
problem.
                                           Region of Concern

                                           Area of Emphasis

                                           Low Probability
                                           for Adverse Effects
                                           Insufficient Data
                                          Additional State
                                          A*f«simtntt

                                           Fish Advisor its
                                           Impaired Wattis
                                           Thr«jt«i«d Waters
Summary:  The upper tidal
James River was characterized
as an Area with Insufficient or
Inconclusive Data because data
were insufficient to describe
the segment. Data were not
available for those chemical
contaminants that were thought
to be problematic in this
system due to historic or
current use.  Additionally,
water and fish tissue chemical
contaminant concentration data
were insufficient, and effects
data were lacking.
Results and Justification: The available data considered in making this characterization were
chemical contaminant concentration data for sediment, water, and fish tissue.  Effects data were
lacking. Although sediment levels of the contaminants measured showed a low probability for
adverse effects on living resources, many of the chemicals that were thought to be problematic,
such as kepone, were not measured. Although the spatial coverage of water chemical
contaminant concentration data was lacking, the available data indicated metals such as
chromium, copper, iron, lead, and zinc were at levels in the water that indicate the potential for
adverse effects on living resources. More relevant chemical contaminant concentration data need
to be collected, along with effects data, to better describe this system.

Additional State Assessments: Currently, this area is included in a health advisory for the
James River due to earlier fishing bans caused by kepone, a substance that has since been
banned. The health advisory covers the mainstem James River and all tidal tributaries from the
fall line at Richmond to the Hampton Roads-Norfolk Bridge Tunnel.  In 1998, in assessing the
conditions of its waters as directed by the Clean Water Act, Virginia did not designate this area
as an impaired or threatened waterbody.
                                            19

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Middle Tidal James River, Virginia
Area with Insufficient or Inconclusive Data
                                          Region oi Concern

                                          Ares of Emphasis

                                          Low Probability
                                          for Adverse Effects
                                          hfuffieient Data
                                         Additional State
                                         Asstscmtnte


                                          Fish Advisories
                                          Impaired Waters
                                          Threatened Waters
Summary:  The middle portion
of the tidal James River was
characterized as an Area with
Insufficient or Inconclusive
Data because data were
insufficient to describe the
segment.  The spatial coverage
of sediment chemical
contaminant concentration and
effects data was poor and there
was no recent water or fish
tissue chemical contaminant
concentration data.
Results and Justification: The available data considered in making this characterization were
chemical contaminant concentration data for sediment and water and effects data (one sediment
toxicity test). Spatial coverage of sediment chemical contaminant concentration data was poor,
and water chemical contaminant concentration data were too old. Although sediment in the
lower portion of the segment was found to cause adverse effects on Bay organisms exposed to it
in the laboratory, spatial coverage of effects data were too limited to describe the entire system.

Additional State Assessments: Currently, this area is included in a health advisory for the
James River due to earlier fishing bans caused by kepone, a substance that has since been
banned. The health advisory covers the mainstem James River and all tidal tributaries from the
fall line at Richmond to the Hampton Roads-Norfolk Bridge Tunnel. In 1998, in assessing the
conditions of its waters as directed by the Clean  Water Act,  Virginia did not designate this area
as an impaired or threatened waterbody.
                                           20

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Lower Tidal James River, Virginia
Area of Emphasis, with special concern for Willoughby Bay
                                                 Region of Concern

                                                 Area of Emphasis

                                                 Low Probability
                                                 for Adverse elects
                                                 Insufficient  Data
                                                Ad ditio nil Stile
                                                Assessments


                                             •  FEh Advisories
                                             •  Impiirtd Wjttis
                                             D  Thrcittntd Waters
Summary:  The lower tidal portion of
the James River was characterized as
an Area of Emphasis because
available water and sediment toxicity
data for Willoughby Bay indicated
evidence of adverse effects on the
Bay's living resources, most likely
due to metals contamination. Since
toxicity also was observed further
upstream in the James River, the
entire segment was characterized as
an Area of Emphasis.  The Elizabeth
River was excluded from this
characterization because it has been
previously designated  a Region of
Concern in 1993.
Results and Justification:  This segment was one of the most extensively sampled segments in a!l of the tidal
tributaries of the Bay. The available data considered in making this characterization were chemical contaminant
concentration data collected throughout the segment for water, sediment, as well as fish tissue and effects data
(water and sediment toxicity tests) collected in the lower and middle portions of the segment. The data convey a
consistent record for the potential for adverse effects on the Bay's living resources.

Both the water and sediment in Willoughby Bay were found to cause adverse effects to Bay organisms exposed to
the water and sediment in the laboratory. In laboratory studies, water and sediment from the Willoughby Bay was
more toxic to animals that live in the Bay than almost all other sites tested in the Bay (ranking third and fifth
respectively out of 46 stations sampled in 16 rivers Baywide).  These stations ranked slightly less toxic than stations
sampled in the nearby Elizabeth River, a known "toxic hot spot," or Region of Concern. The combined toxicity of
metals in the sediment such as arsenic, copper, lead, mercury, nickel, and zinc may account for a major portion of
the toxicity observed in Willoughby Bay. Organic contaminants such as pesticides and polynuclear aromatic
hydrocarbons (PAHs) were not detected.

Available data also provided evidence for chemical contamination problems in areas of this segment outside
Willoughby Bay. Sediment and water at two locations above and below Newport News in the middle portion of the
segment were found to cause adverse effects on Bay organisms, but to a lesser degree than in Willoughby Bay.
Additionally, contaminant concentrations in ambient water in the upper portion of the segment in 1990 revealed
levels of copper, zinc, and nickel high enough to raise concern about the potential for adverse effects in this area.
Although these data are too old to represent current water conditions and analysis methods have improved since
these data were collected, they provided supporting evidence for the potential for upstream problems.

Caveats/Limitations: Sediment contaminant concentration data for kepone and tributyitin, two substances of great
concern in this region, were not available.  Future assessments in the upper portion of this segment will be helpful in
better characterizing the degree of toxicity upstream.

Additional State Assessments: In 1998, in assessing the conditions of its waters as directed by the Clean Water
Act, Virginia designated sections of this segment as "threatened waters" due to chemical contamination.  Currently,
this river segment is included in a health advisory for the James River due to earlier fishing bans caused by kepone,
a substance that has since been banned. The health advisory covers the mainstem James River and all tidal
tributaries from the fall line at Richmond to the Hampton Roads Bridge Tunnel.
                                                   21

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Tidal Magothy River, Maryland
Area of Emphasis, with the need for additional data to confirm characterization
                                         Region of Concern

                                         Area of Emphasis

                                         Low Probability
                                         for Adverse Effects
                                         Insufficient Data
                                        Additional Stale
                                         Assessments

                                      •  Fish Advisories
                                      •  Impaired Waters
                                      Q  Thitjtcned Waters
Summary: The tidal Magothy
River was characterized as an
Area of Emphasis because
sediment contaminant levels
and sediment and water toxicity
tests provided evidence of
adverse effects on the Bay's
living resources. Contaminants
in the sediment such as arsenic
and polynuclear aromatic
hydrocarbons (PAHs) were at
levels where adverse effects on
living resources are probable.
                                                           Results and Justification:
                                                           The available data considered
in making this characterization were chemical contaminant concentration data for sediment and
water and effects data (sediment and water toxicity tests, benthic community assessments). The
water and sediment in the Magothy River was found to cause adverse effects on Bay organisms
exposed to the water and sediment in the laboratory. The sediment in the upstream area near
South Ferry was found to more toxic than the sediment in lower portion of the river at Gibson
Island. The sediment near South Ferry was more toxic to animals that live in the sediments than
most other sediments tested in the Bay (ranking ninth out of 46 stations sampled in 16 rivers
Baywide. Sediment contaminant concentrations of lead, arsenic, and PAHs were elevated to
levels where adverse effects on living resources are probable. Downstream, where there was a
lesser degree of toxicity, levels of PAHs were elevated.  Degraded benthic communities appear
to be caused by low dissolved oxygen levels. Although the spatial coverage of data was
somewhat limited, the evidence of elevated levels of contaminants and associated toxicity, both
upstream and downstream, was sufficient evidence of the potential of adverse impacts in this
river.

Caveats/Limitations: The characterization of this river was driven largely by the observance of
water and sediment toxicity at sites in the upper and middle portions of the river.  However, with
the exception of a few contaminants, many of the measured contaminants were below levels that
may cause probable effects on living resources.  Future assessments of both chemical
contaminant concentration and effects data are recommended to confirm this initial
characterization.

Additional State Assessments: In 1998, in assessing the conditions of its waters as directed by
the Clean Water Act, Maryland did not designate this segment as impaired by chemical
contaminants.  Based on the data evaluated by the state, there was no evidence of a water quality
standards violation.
                                           22

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Manokin River, Maryland
Area with Insufficient or Inconclusive Data
                                           Region of Concern

                                           Area of Emphasis

                                           Low Probability
                                           for Adverse Effects
                                           Insufficient Data
                                          Addition!) Stilt
                                          Assessments


                                        •  Fish Advisories
                                        •  Impiii«d Waters
                                        B  Thrnttntd WJteri
                                                              Summary:  The Manokin
                                                              River was characterized as an
                                                              Area with Insufficient or
                                                              Inconclusive Data because
                                                              data were insufficient both
                                                              spatially and temporally to
                                                              describe the conditions in the
                                                              river. Additionally, some of
                                                              the available data were
                                                              inconclusive.

                                                              Results and Justification:
                                                              The available data considered
                                                              in making this
                                                              characterization were
chemical contaminant concentration data for sediment and fish tissue and effects data (benthic
community assessments).  Sediment chemical contaminant concentration data were spatially and
temporally limited and fish tissue data were too old to represent current conditions in the
segment. Although the sediment chemical contaminant concentration data indicate levels of
chemical contaminants that were unlikely to cause adverse effects on living resources, benthic
communities in one out of the three areas sampled were degraded, and low dissolved oxygen
does not appear to be a problem. Additional assessments are necessary to characterize this river.

Additional State Assessments: In 1998, in assessing the conditions of its waters as directed by
the Clean Water Act, Maryland did not designate the river as impaired by chemical
contamination.
                                           23

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 Tidal Mattaponi River, Virginia
 Area with Insufficient or Inconclusive Data
                                           Region of Concern

                                           Area of Emphasis

                                           Low Probability
                                           for Adverse Effects
                                           Insufficient Data
                                          Additional State
                                          Assessment;


                                        •  Fish Advisories
                                        •  Impaired Waters
                                        B  Thriit«fie
-------
Tidal Middle River, Maryland
Area of Emphasis, with limited data in eastern portion of river
                                       m
Region of Concern

Ar«»ot Emphasis

Low Probability
for Adverse Effects
Insufficient  Data
                                         AdditnnilStJtt
                                          Aitessmtntf


                                       •  Fih Advisories
                                       •  Impiirtd WJttrj
                                       Q  Thrtittntd Wjteu
                                                             Summary: The tidal Middle
                                                             River was characterized as an
                                                             Area of Emphasis because
                                                             available water chemistry and
                                                             toxicity data provided
                                                             evidence of a chemical
                                                             contaminant problem thought
                                                             to be associated with metals
                                                             contamination. Data for the
                                                             eastern portion of the river
                                                             were lacking.

                                                             Results and Justification:
                                                             The available data considered
                                                             in making this
characterization were chemical contaminant concentration data for water and sediment and
effects data (water and sediment toxicity tests). Although data are lacking for the eastern section
of the river, the elevated levels of metals in the water column and the associated ambient water
toxicity were sufficient data to indicate the potential for adverse effects in this river.

Water collected from the Middle River in both the fall and spring seasons was found to cause
adverse effects to Bay organisms when exposed to it in the laboratory.  This toxicity was thought
to be caused by metals such as copper and nickel which were at levels  that could cause adverse
effects on living resources. When compared to a total of 46 stations sampled in 16 rivers
Baywide, the two sites tested for ambient toxicity in the Middle River  ranked fourth and eighth
highest for ambient water toxicity.  Although sediment toxicity was not observed, elevated levels
of lead, nickel, zinc,  and several polynuclear aromatic hydrocarbons (PAHs) were detected.

Caveats/Limitations:  Future assessments in the eastern portion of this river will be helpful in
confirming this initial characterization.

Additional State Assessments: In 199S, in assessing the conditions of its waters as directed by
the Clean Water Act, Maryland designated this area as a chemical contaminant-impaired
waterbody and placed it on a priority list of waters to manage.
                                            25

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Nanticoke River, Maryland
Area with Low Probability far Adverse Effects, with the cause of benthic degradation unknown.
                                          Region of Concern

                                          ATM of Emphasis

                                          Low Probability
                                          for Adverse Effects
                                          hsufficient Data
                                         Ad Ditto nil St«tt
                                          Af» tsi me nts


                                           Fsh Advisories
                                           Impjiitd Waters
                                          Thr*jt*n*d Wittrs
                                                             Summary:  The Nanticoke
                                                             River was characterized as an
                                                             Area with Low Probability
                                                             for Adverse Effects because
                                                             levels of contaminants in the
                                                             water and sediment were
                                                             below those associated with
                                                             adverse effects on living
                                                             resources. Additionally, the
                                                             sediment and water showed
                                                             no toxicity, and benthic
                                                             communities were healthy.

                    	                               Results and Justification:
                                                             The available data considered
                                                             in making this
characterization were chemical contaminant concentration data for sediment and effects data
(water/sediment toxicity tests and benthic community assessments).  The levels of contaminants
in the sediment are below levels associated with adverse effects on living resources.  The
sediment and water showed no significant toxicity when Bay organisms  were exposed to the
water and sediment in the laboratory. Benthic communities were healthy at two out of the three
sites sampled. The cause of benthic degradation at the third site does not appear to be due to
sediment contamination. Although the spatial coverage of data was sparse, the high level of
confidence in the ambient toxicity data indicating no effects and the supporting chemical
contaminant concentration and benthic community data provided enough weight of evidence to
assume a low probability for adverse effects in this river.

Caveats/Limitations:  At one station, the cause of benthic community degradation is unknown.
The degradation does not appear to be due to low dissolved oxygen nor due to chemical
contamination.  The workgroup did not have a reason to believe that contaminants in the
sediment were higher than those thought likely to cause adverse effects on living resources.
Future assessments should clarify the cause of this benthic degradation.

Additional State Assessments: In 1998, in assessing the conditions of its waters as directed by
the Clean Water Act, Maryland did not designate this area as  impaired by chemical
contamination.
                                           26

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Northeast River, Maryland
Area with Insufficient or Inconclusive Data
                                            Region of Concern

                                            Area of Emphasis

                                            Low Probability
                                            lor Adverse Effects
                                            Insufficient Data
                                           Addition*! Stjtc
                                           Assessments
                                        •  Fish Advisotits
                                        •  Impaired Water;
                                        Q  Threittned Waters
                                                              Summary: The Northeast
                                                              River was characterized as an
                                                              Area with Insufficient or
                                                              Inconclusive Data because
                                                              the temporal and spatial
                                                              coverage of sediment data
                                                              was insufficient to describe
                                                              the system. No water or fish
                                                              tissue chemical contaminant
                                                              concentration data or effects
                                                              data were available.
                                                              Results and Justification:
                                                              The available data considered
                                                              in making this
                                                              characterization were
chemical contaminant concentration data for sediment.  No effects data were available. The
sediment chemical contaminant concentration data revealed metals such as arsenic, zinc, and
nickel and a few polynuclear aromatic hyrdocarbons (PAHs) at levels that indicate probable
adverse effects on living resources. Although these data provided evidence for the potential for
adverse effects, data were too sparse to adequately characterize the entire river.

Additional State Assessments:  In 1998, in assessing the conditions of its waters as directed by
the Clean Water Act, Maryland designated a section in the lower portion of the river as a
chemical contaminant-impaired waterbody and placed it on a priority list of waters to manage.
This information will be considered in making a future characterization of this area once all
available data have been acquired.
                                            27

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Tidal Pamunkey River, Virginia
Area with Insufficient or Inconclusive Data
                                       | Region of Concern

                                       fflll Area of Emphasis

                                       E3 Low Probability
                                          for Adverse Effects
                                       fT-l Insufficient Data
                                         AdditionjIStite
                                          Ass «»mcnts


                                       •  Fish Advisories
                                       •  Impaired Wjters

                                       B  Thf«jtin«d Wjttis
                                                             Summary: The tidal
                                                             Pamunkey River was
                                                             characterized as an Area with
                                                             Insufficient or Inconclusive
                                                             Data because data conflicted
                                                             and were therefore
                                                             inconclusive.

                                                             Results and Justification:
                                                             The available data considered
                                                             in making this characterization
                                                             were chemical contaminant
                                                             concentration data for
                                                             sediment and water and effects
                                                             data (sediment toxicity test).
Overall, the fairly good spatial coverage of recent sediment data showed levels of chemical
contaminants that are considered unlikely to cause adverse effects on living resources. However,
at one site in the lower portion of the river, polynuclear aromatic hydrocarbons (PAHs) were
found at levels in the sediment that are thought to cause probable adverse effects. Additionally,
the sediment in the lower portion of the river showed evidence of adverse effects to Bay
organisms exposed to it in the laboratory, although little weight was placed on these data due to
poor survival of test organisms in the control (clean) sediments during the laboratory test.
Because data were conflicting, this river has been initially characterized as an Area with
Insufficient or Inconclusive Data. Additional assessments are needed to make a characterization
in the future.

Additional State Assessments: In 1998, in assessing the conditions of its waters as directed by
the Clean Water Act, Virginia did not designate the river as impaired by chemical contamination.
                                           28

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Upper Tidal Patuxent River, Maryland
Area of Emphasis
                                            Region of Concern

                                            Area of Emphasis

                                            Low Probability
                                            for Adverse Effects
                                            Insufficient Data
                                           AdditionilStlt*
                                           A5> tn mints


                                        •  Ffeh Advisories
                                        •  Impjirtd Waters
                                        Q  Thic*t*n«d Waters
Summary:  The upper tidal
Patuxent was characterized
as an Area of Emphasis
because available data
indicated that levels of
pesticides in the water and
sediment were at levels that
indicate probable adverse
effects on living resources,
with supporting evidence
of water toxicity and
degraded benthic
communities.
                                                               Results and Justification:
                                                               The available data
considered in making this characterization were chemical contaminant concentration data for
water and sediment and effects data (sediment toxicity tests).  Pesticides in the water
(chlorpyrifos and malathion) and sediment (DDT) were at levels indicative of probable adverse
effects on living resources in both the upper and lower portions of the segment. The water in the
lower portion of the segment was slightly toxic to Chesapeake Bay organisms exposed to the
water in the laboratory. Benthic communities were degraded at several sites in the middle
portion of the river and may be a result of chemical contamination, since dissolved oxygen levels
do not appear to be problematic.  Polynuclear aromatic hydrocarbons were at levels in the
sediment that indicate probable adverse effects on living resources in the lower portion of the
segment, although sediment toxicity was not observed. The weight of sediment and water
chemical contaminant concentration data, water toxicity data,  and the degraded benthic
communities was enough to characterize this segment as an Area of Emphasis.

Caveats/Limitations: Future assessments of effects in this river will be helpful in confirming
this initial characterization.

Additional State Assessments:  In 1998, in assessing the conditions of its waters as directed by
the Clean Water Act, Maryland designated portions of this segment as impaired and placed it on
a priority list to manage.  The Bay Program characterization considered additional data that were
not available at the time of the state's analysis. Future state efforts will consider additional data,
as it becomes available.
                                           29

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Middle Tidal Patuxent River, Maryland
Area of Emphasis
                                            Region of Concern

                                            Area of Emphasis

                                            Low Probability
                                            for Adverse Effects
                                            Insufficient Data
                                           AdditionjISiJtc
                                            Assuf mtnfc

                                         •  Fish Advisories
                                         •  Impiiitd Waters
                                         B  Thrutinc
Summary:  The middle
section of the tidal Patuxent
River was characterized as
an Area of Emphasis
because available data
indicated that pesticides in
the water and sediment
were at levels that indicate
probable adverse effects on
the Bay's living resources.
Additionally, the water and
sediment were found to be
toxic.
                                                                Results and Justification:
                                                                The available data
considered in making this characterization were chemical contaminant concentration data for
Water, sediment, and fish and effects data (water and sediment toxicity tests). In the upper
portion of the segment, recent pesticide (chlorpyrifos) levels in the water and sediment were at
levels indicating probable adverse effects on living resources. In the lower portion of this
segment, metals and the banned pesticide DDT were found at levels that could cause adverse
effects on living resources.  Additionally, the water and sediment were found to cause adverse
effects on Bay organisms exposed to the water and sediment in the laboratory.  The contaminant
levels, coupled with water and sediment toxicity, provided evidence of a chemical contaminant
problem in the lower portion of this segment.  Even though the fish tissue data were too old to be
representative of current conditions and the spatial coverage of the sediment and water
contaminant concentration data was not adequate, the water and sediment chemical contaminant
concentration and effects data provide sufficient evidence for the potential for adverse effects on
living resources in this section of the Patuxent River.

Caveats/Limitations: Future assessments of effects in this river will be helpful in confirming
this initial characterization.

Additional State Assessments:  In 1998, in assessing the conditions of its waters as directed by
the Clean Water Act, Maryland did not designate this area as impaired by chemical contaminants.
Based on the data evaluated by the state, there was no evidence of a  water quality standards
violation. Furthermore, the Bay Program characterization considered additional data that were
not available at the time of the state's analysis. Future state efforts will consider additional data
as it becomes available.
                                            30

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Lower Tidal Patuxent River, Maryland
Area with Insufficient or Inconclusive Data, with potential for toxicity near Broomes Island.
                                             Region of Concern

                                             Ar»aof Empha»t

                                             Low Probability
                                             for fldvene Bf«ctf
                                             insufficient Data
                                            Additional State
                                             Assessments

                                          •  Ffch Advisories
                                          •  Impjlrid Wjttrs
                                          Q  Thiettened Witers
Summary:  The lower tidal
Patuxent River was characterized
as an Area with Insufficient or
Inconclusive Data, with the
potential for toxicity in the
middle of the segment, near
Broomes Island.  Although there
was fairly good spatial coverage
of recent water and sediment
chemical contaminant
concentration data and effects
data were available, the data
were inconclusive and did not
provide consistent, conclusive
evidence to make a segment-
wide characterization.
Results and Justification: The available data considered in making this characterization were sediment,
water, and fish tissue chemical contaminant concentration data and effects data (sediment/water toxicity
tests and benthic community assessments). Near Broomes Island, water taken from the river was found
to cause adverse effects to Bay organisms exposed to it in the laboratory. In the laboratory studies, water
from near Broomes Island was more toxic to animals that live in the water than almost all other waters
tested in the Bay (ranking third out-of 46 stations sampled in 16 rivers Baywide). Benthic communities
in this area were degraded, although sediment toxicity was not reported. Additionally, a pesticide
(endosulfan II) was at levels indicative of probable adverse effects on living resources.

Although the spatial coverage of recent water and sediment chemical contaminant concentration data
was good and biological effects data were available, the data did not provide sufficient evidence of a
segment-wide chemical contaminant problem to characterize the entire segment as an Area of Emphasis.
Likewise, the majority of the segment could not be considered an Area with Low Probability for Adverse
Effect because some metals such as arsenic and nickel upstream of Broomes Island were at levels in the
sediment that are associated with probable adverse effects on living resources. Additionally, benthic
communities were degraded in several areas throughout the segment. Since the data were inconclusive,
this area was characterized as an Area with Insufficient or Inconclusive Data. Additional assessments are
needed to better characterize the nature of chemical contaminant-related problems in this segment.

Caveats/Limitations: Future assessments of effects in this river will be helpful in confirming this initial
characterization.

Additional State Assessments: In 1998, in assessing the conditions of its waters as directed by the
Clean Water Act, Maryland did not designate the river as impaired by chemical contamination.  Based on
data evaluated by the state, there was no evidence of a water quality standard violation. Furthermore, the
Bay Program characterization considered additional data that were not included in the state's analysis.
Future state efforts will consider additional data as it becomes available.
                                               31

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Pocomoke River, MarylancWirginia
Area with Insufficient or Inconclusive Data
                                          Region of Concern

                                          Ar«»of Emphasis

                                          Low Probability
                                          for Adverse Hfects
                                          Insufficient Data
                                         Addition!] Statt
                                       •   Ftfh Advisories
                                       •   Impjiitd Wit*»
                                       B   Thr.jtirnd Wjt«(l
Summary:  The Pocomoke
River was characterized as an
Area with Insufficient or
Inconclusive Data because the
available data were
insufficient to describe the
segment. The sediment
chemical contaminant
concentration data were too
limited temporally and
spatially to adequately
describe the system, and no
water chemical contaminant
concentration data or effects
data were available.
Results and Justification: The available data considered in making this characterization were
chemical contaminant concentration data for sediment and fish tissue.  No effects data were
available. Although the sediment chemical contaminant concentration data were too limited to
describe the river, the available data indicated the unlikelihood of adverse effects on living
resources. At the time this characterization was made, a preliminary study found elevated levels
of metals (arsenic, selenium, and lithium) and steroids in the water.  Follow-up studies are under
way and will be used to update this characterization.

Additional State Assessments: In 1998, in  assessing the conditions of its waters as directed by
the Clean Water Act, Maryland and Virginia did not designate the river as impaired by chemical
contamination.
                                           32

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Upper Tidal Potomac River, Maryland
Area of Emphasis
                                              Region of Concern

                                              Areaot Emphasis

                                              Low Probability
                                              for Adverse Effects
                                              Insufficient Data
                                             Addition^ State
                                              Assessments


                                               Fish Advisories
                                               Impelled Waters

                                               Thitatened Wjttrt
                                                                   Summary: The portion of the
                                                                   tidal Potomac River was
                                                                   characterized as an Area of
                                                                   Emphasis because metals were
                                                                   found in sediment throughout
                                                                   the river at levels that suggest
                                                                   probable adverse effects on
                                                                   living resources.  Available
                                                                   sediment toxicity data in the
                                                                   lower portion of this segment
                                                                   indicated adverse effects on
                                                                   living resources, most likely
                                                                   due to the presence of metals
                                                                   contamination. The Anacostia
                                                                   River was  excluded from this
                                                                   characterization because it has
                                                                   been previously designated a
                                                                   Region of Concern in 1993.

Results and Justification:  The available data considered in making this characterization were chemical
contaminant concentration data for water, sediment, and fish tissue and effects data (water and sediment
toxicity tests). There was good spatial coverage of sediment chemical contaminant concentration data.
Metals such as copper, zinc, and nickel were found in sediment throughout the river at levels that
indicate probable adverse effects on living resources.  At various locations in the segment,
polychlorinated biphenyls (PCBs) were at levels that indicate possible adverse effects on living
resources. Elevated levels of polynuclear aromatic hydrocarbons (PAHs) were detected in the sediment
downstream of the Anacostia River.  The sediment collected from the lower portion of this segment was
found to cause adverse effects to Bay organisms when exposed to it in the laboratory. When compared
to a total of 46 stations sampled in 16 rivers Baywide, one station ranked tenth highest for sediment
toxicity, most likely due to metals. Even though no effects data were available for the upper portion of
this segment, the pervasive elevated levels of metals, the persistent elevated levels of PAHs in the upper
portion of the segment, and the sediment toxicity observed in the lower portion of the segment provided
sufficient evidence of the potential for adverse effects in this section of the Potomac River.

Caveats/Limitations: Future assessments of effects in this river will be helpful in confirming this initial
characterization.

Additional State Assessments: In 1998, in assessing the conditions of its waters as directed by the
Clean Water Act, Maryland designated a portion of this segment as impaired. This area has been placed
on a priority list of waters to manage. In April 1999, a PCB fish consumption advisory was placed on
the tidal Potomac River (from the Woodrow Wilson Bridge to Smith Point, MD/Brent Point) for channel
catfish larger than 18 inches (limit consumption to no more than 1 8 oz meal/month). In addition,
caution  was recommended when eating carp and eel.
                                              33

-------
Middle Tidal Potomac River, Maryland
Area of Emphasis
                                          Region of Concern

                                          Area of Emphasis

                                          Low Probability
                                          for Adverse Effects
                                          Insufficient Data
                                         AddiiionalStJt*
                                         Assessments

                                       •  Fsh Advisories
                                       •  Impjired Witeis
                                       Q  Thieitentd Wit«u
Summary: The middle
portion of the tidal Potomac
River was characterized as an
Area of Emphasis because
metals found in the sediment
throughout the river and
pesticides found in the upper
and lower portions of the
segment were at levels that
indicate probable effects on
living resources. Also, the
sediment showed some degree
oftoxicity.
Results and Justification:  The available data considered in making this characterization were
chemical contaminant concentration data for water and sediment and effects data (water and
sediment toxicity tests).  Throughout the segment, nickel was at levels in the sediment that
indicate adverse effects on living resources.  In the upper and lower reaches of this segment,
pesticides were found in sediment at levels that indicate adverse effects on living resources. At
various locations in the segment, polychlorinated biphenyls (PCBs) were at levels in the
sediment that indicate possible adverse effects on living resources. In the lower portion of the
segment, sediment showed some degree oftoxicity. Water chemical contaminant concentration
data collected in the upper and lower portions of this segment in the late 1980s and early 1990s
revealed levels of metals such as copper, zinc, cadmium, lead, and nickel high enough to raise
concern about potential contamination problems in this area.  Although these data are too old to
represent current water quality conditions, they provided supporting evidence for the potential
for adverse effects. There was sufficient sediment data, toxicity data, and supporting (yet older)
water data to indicate the potential for adverse effects.

Caveats/Limitations: Future assessments of effects in this river, particular in the upper and
middle portions of the segment, will be helpful in confirming this initial characterization.

Additional State Assessments: In 1998, in assessing the conditions of its waters as directed by
the Clean Water Act, Maryland designated portions of this segment as  a chemical contaminant-
impaired waterbody and placed it on a priority list of waters to manage. In April 1999, a PCB
fish consumption advisory was placed on the tidal Potomac River (from the Woodrow Wilson
Bridge to Smith Point, MD/Brent Point) for channel catfish larger than 18 inches (limit
consumption to no more than 1 8 oz meal/month). In addition, caution was recommended when
eating carp and eel.
                                           34

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Lower Tidal Potomac River, Maryland
Area with Low Probability for Adverse Effects, with the need for additional data to confirm
characterization
                                             Region of Concern

                                             Area of Emphasis

                                             Low Probability
                                             for Adverse Effects
                                             ^sufficient Data
                                            Additional State
                                             Assessments


                                             Fith Advisories
                                             Impiired Wjie»
                                             Thriitened Wjttts
                                                                 Summary:  The lower tidal
                                                                 Potomac River was characterized
                                                                 as an Area with Low Probability
                                                                 for Adverse Effects because the
                                                                 excellent spatial coverage of
                                                                 recent sediment contaminant
                                                                 levels throughout the river are
                                                                 below levels associated with the
                                                                 potential for causing adverse
                                                                 effects on living resources.

                                                                 Results and Justification:  The
                                                                 available data considered in
                                                                 making this characterization
                                                                 were chemical contaminant
                                                                 concentration data for sediment,
                                                                 water, and fish tissue.  No effects
data were available. The spatial and temporal coverage of recent sediment chemical contaminant
concentration data was excellent and, for the most part, indicated levels of chemical contaminants that
were below levels associated with adverse effects on living resources. The fish tissue data were too old
to be representative of current conditions, the spatial coverage of water chemical contaminant
concentration data was poor, and effects data were lacking. However, the sediment chemical
contaminant concentration data were plentiful and recent, and the preponderance of evidence indicated
that adverse effects are unlikely.

Caveats/Limitations: Although the preponderance of evidence suggested a low likelihood of adverse
effects on living resources, there was conflicting evidence that needs further  evaluation. Some levels of
contaminants in three Virginia shore creeks indicated the potential  for adverse effects, these data stored
in the STORET database were ambiguous and the precision and sensitivity of the analytical methods
were unknown. Benthic communities were degraded in several areas on the southern shore of this
segment, where dissolved oxygen did not appear to be the problem. A more  thorough quality check of
the STORET data and additional assessments in this area of the lower Potomac are necessary to confirm
this initial characterization.

Additional State Assessments: In 199S, in assessing the conditions of its waters as directed by the
Clean Water Act, Maryland did not designate the river as impaired by chemical contamination.  Based on
data evaluated by the state, there was no evidence of a water quality standard violation.  Virginia
designated a few small creeks on the southern side of this segment  as "threatened waters" due to
chemical contamination in the sediment.  These creeks will be targeted by Virginia for future
assessments.  The Bay Program characterized the entire segment of this river and not individual creeks.
Even though there was evidence for a site specific problem in a small creek, the overwhelming weight of
evidence indicated that, overall, this segment had a low probability for adverse effects.
                                              35

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Upper Tidal Rappabannock River, Virginia
Area with Low Probability for Adverse Effects, with a site-specific contaminant problem
                                         Region of Concern

                                             Emphasis
                                         Low Probability
                                         lor Adverse Effects
                                         Insufficient Data
                                        Additional State
                                         Assessment!


                                         Fish Adnsories
                                      D  Thieitentd Wjters
                                                           Summary: The upper tidal
                                                           Rappahannock River was
                                                           characterized as an Area with
                                                           Low Probability for Adverse
                                                           Effects because the good spatial
                                                           coverage of recent sediment
                                                           chemical contaminant
                                                           concentration data indicated that
                                                           levels of contaminants were
                                                           well below levels  associated
                                                           with adverse effects. Data
                                                           provide sufficient  evidence that
                                                           polynuclear aromatic
                                                           hydrocarbons (PAHs) in the
                                                           sediment from  a superfund site
in the upper portion of this segment are localized in a tributary and are not transported
downstream.

Results and Justification:  The available data considered in making this characterization were
chemical contaminant concentration data for sediment, water, and fish tissue and effects data
(sediment toxicity tests).  The excellent spatial coverage of recent sediment contaminant data
indicated that levels were well below those associated with adverse effects on living resources.
Sediment taken from the lower portion of the river segment was found to be not toxic to Bay
organisms when exposed to the sediment the laboratory. Although recent water and fish tissue
chemical contaminant concentration data and good spatial coverage of effects data were lacking,
the sediment chemical contaminant concentration data conveyed a consistent story that adverse
effects were unlikely in this area.

In the far upstream portion of the tidal Rappahannock River, remarkably high levels of PAHs
were observed in close proximity to a former wood preserving facility that used  creosote (a wood
preservative).  The area of the Rappahannock near this facility has been designated  as a
superfund site.  The available data indicate that the PAH sediment contamination is localized and
is not transported downstream. Therefore, overall, this section of the Rappahannock has a very
low probability for adverse impacts on living resources, with a site specific  contamination
problem that is being addressed.

Additional State Assessments: In 1998, in assessing the conditions of its waters as directed by
the Clean Water Act, Virginia did not designate this area as an impaired or threatened waterbody.
In 1986, the EPA placed a portion of the river which is in close proximity to a former wood
preserving facility on its National Priority List.  Clean up actions were taken to address the
contamination problem caused by creosote.
                                           36

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Middle Tidai Rappahannock River, Virginia
Area with Insufficient or Inconclusive Data, with potential contamination at one site.
                                       ^|  Region of Concern

                                       [flj  Area of Emphasis

                                       Efj  Low Probability
                                       ~™  for Adverse Btects
                                       [!^]  Insufficient Data
                                          Ad ditto nil Stite
                                          Ajsessm«nts


                                        •  Fish Advisories
                                        •  Impjirtd Witers
                                        a Thi*it*ntd Waters
Summary:  The middle
portion of the tidal
Rappahannock River was
characterized as an Area with
Insufficient or Inconclusive
Data, with the potential for
contamination at one site.
Although the available data
indicated that the rest of the
segment  had a lower
likelihood of a chemical
contaminant problem, the
spatial coverage of the data
was insufficient to make a
definite characterization.
Results and Justification: The available data considered in making this characterization were
chemical contaminant concentration data for sediment, water, and fish tissue and effects data
(sediment toxicity test). One station near the mouth of the Famham Creek in the lower portion
of this segment showed levels of polynuclear aromatic hydrocarbons (PAHs) at levels that
indicate probable adverse effects on living resources.  The sediment chemical contaminant
concentration data indicate levels of chemical contaminants that are unlikely to cause adverse
effects on living resources. Sediment taken from one location in the upper portion of the
segment was not toxic to Bay organisms exposed to the sediment in the laboratory.  Even though
these data showed evidence that a chemical contaminant problem is unlikely outside of the one
problem site, the fish and ambient water chemical contaminant concentration data and the effects
data were too spatially limited to confirm this.

Additional State Assessments: In 1998, in assessing the conditions of its waters as directed by
the Clean Water Act, Virginia did not designate this area as an impaired or threatened waterbody.
                                           37

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Lower Tidal Rappahannock River, Virginia
Area with Low Probability for Adverse Effects, with limited effects data
                                       ^  Region of Concern

                                       [jj]  Area of Emphasis

                                       CS  Low Probability
                                       ™  for Adverse Etlects
                                       fTH]  Insufficient Data
                                          Additional StJtt
                                          Assessments

                                       •>  Fish Advtsoiits
                                       •  Impiiitd Wfttis
                                       Q  Thruten.d Wittrt
Summary:  The lower tidal
Rappahannock River was
characterized as an Area with
Low Probability for Adverse
Effects because the recent
sediment chemical
contaminant concentration
data with good spatial
coverage indicated that levels
of contaminants were well
below levels associated with
adverse effects.
                                                             Results and Justification:
                                                             The available data considered
in making this characterization were chemical contaminant concentration data for sediment,
water, and fish tissue and effects data (sediment toxicity test).  Overall, levels of contaminants in
the sediment were well below those associated with adverse effects on living resources and the
sediment sampled at one location was not toxic to Bay organisms exposed  to it in the laboratory.
Although the recent water and fish tissue chemical contaminant concentration data and sediment
toxicity data did not have good spatial coverage, they provided supporting  evidence for this
characterization.

Caveats/Limitations: Sediment was tested for toxicity at only one site in the upper portion of
this river segment. Future effects assessments are needed on a broader spatial scale to confirm
this initial characterization.

Additional State Assessments:  In 1998, in assessing the conditions of its waters as directed by
the Clean Water Act, Virginia did not designate any waterbodies in this segment as impaired by
chemical contamination. However, they did identify a small creek (Urbana Creek) as threatened.
The Bay Program characterized the entire segment of this river and not individual creeks.  Even
though there was evidence for a site specific problem in a small creek, the overwhelming weight
of evidence indicated that, overall, this segment had a low probability for adverse effects.
                                            38

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Sassafras River, Maryland
Area with Low Probability for Adverse Effects
                                           Region of Concern

                                           Areaot Emphasis

                                           Low Probability
                                           for Adverse Effects
                                           Insufficient Data
                                          Additional State
                                        4)  Fish Ad vis odes
                                        •  Impaired Waters
                                        D  Threatened Waters
 Summary: The Sassafras
 River was characterized as an
 Area with Low Probability
for Adverse Effects because
 the fairly good spatial
 coverage of recent sediment
 chemical contaminant
 concentration data indicated
 that levels of contaminants
 were, for the most part,
 below those associated with
 adverse effects on living
 resources.  The sediment
 showed no toxicity and water
 showed very low toxicity,
 and benthic communities
 were healthy.
Results and Justification: The available data considered in making this characterization were
chemical contaminant concentration data for sediment and effects data (water and sediment
toxicity tests and benthic community assessments).  The water showed a low degree of toxicity
to Bay organisms exposed to the water in the laboratory.  The spatial coverage of recent sediment
chemical contaminant concentration data was fairly good and, for the most part, indicated levels
of multiple chemical contaminants below levels associated with adverse effects on living
resources. Even though some contaminants in the sediment were at levels that indicate probable
adverse effects on living resources, the sediment was not found to be toxic to Bay organisms
exposed to it in the laboratory. Furthermore, the benthic communities living in the sediment
were found to be healthy.

Additional State Assessments: In 1998, in assessing the conditions of its  waters as directed by
the Clean Water Act, Maryland did not designate this area as impaired by chemical
contamination.
                                           39

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Tidal Severn River, Maryland
Area of Emphasis
                                        m Region of Concern

                                        IU] ATM of Emphasis

                                        pg Low Probability
                                        ™ for Adverse Effects
                                        FT] Insufficient Data
                                          Ad ditto Ml State
                                           Assessments


                                            Fish Advisories
                                            Impaired Waters
                                            Thr«jttn«d nVitcrs
Summary:  The tidal
Severn River was
characterized as an Area of
Emphasis because recent
data indicated widespread
metals, polynuclear aromatic
hydrocarbons (PAHs), and
some pesticides for multiple
years at levels that indicate
probable adverse effects on
living resources.
Additionally, there was
supporting evidence of
sediment and water toxicity.
Results and Justification: The available data considered in making this characterization were
chemical contaminant concentration data for water and sediment and effects data (water and
sediment toxicity tests and benthic community assessments). Metals (such as copper, zinc, and
nickel) throughout the tidal river, pesticides (lindane, DDT) in the upper and middle river, and
PAHs in the middle and lower river were at levels in the sediment that indicate probable adverse
effects on living resources. The water and sediment were found to cause adverse effects to Bay
organisms when exposed to the water and sediment in the laboratory. Even though benthic
communities appeared to be healthy in the Severn River, the widespread elevated levels of
multiple chemicals over multiple years and the toxicity data provided sufficient evidence for the
potential for adverse effects in this river.

Caveats/Limitations:  Future assessments of effects data in this river will be helpful in
confirming this initial characterization.

Additional State Assessments: In 1998, in assessing the conditions of its waters as directed by
the Clean Water Act, Maryland did not designate this area as impaired by chemical contaminants.
Based on the data evaluated by the state, there was no evidence of a water quality standards
violation. Furthermore, the Bay Program characterization considered additional data that were
not included in the state's analysis. Future state efforts will consider additional data as it
becomes available.
                                            40

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Tidal South/Rhode Rivers, Maryland
Area with Insufficient or Inconclusive Data
                                           Region of Concern

                                           Area of Emphasis

                                           Low Probability
                                           lor Adverse Effects
                                           Insufficient Data
                                          Additional State
                                          Asitsimtnts


                                       •   Ffcti Advisories
                                       •   Impaired Wjftri

                                       Q   Thrtittnerf Wjttrs
                                                              Summary:  The South/Rhode
                                                              River area was characterized
                                                              as an Area with Insufficient or
                                                              Inconclusive Data because
                                                              available data were spatially
                                                              and temporally insufficient to
                                                              describe this system.

                                                              Results and Justification:
                                                              The only available data for
                                                              this area were sediment
                                                              chemical contaminant
                                                              concentration data which had
                                                              poor spatial coverage and fish
                                                              tissue chemical contaminant
concentration data which were too old to be representative of current conditions. No current
ambient water or fish tissue chemical contaminant concentration or effects data  were available.
Since sediment and ambient water toxicity data and concurrent sediment and water chemical
contaminant concentration data will be available later in 1999 from a Bay Program funded study
(as well as some previously collected sediment toxicity data from Maryland Department of
Natural Resources), this area initially has been characterized as an Area with Insufficient or
Inconclusive Data until the data are available and analyzed for future updates to the
characterization.

Caveats/Limitations: Future assessments of effects in this river will be helpful  in confirming
this initial characterization.

Additional State Assessments: In 1998, in assessing the conditions of its waters as directed by
the Clean Water Act, Maryland did not designate the river as impaired by chemical
contamination. Based on data evaluated by the state, there was no evidence of a water quality
standard violation. Furthermore, the Bay Program characterization considered additional data
that were not included in the state's analysis. Future state efforts will consider additional data as
it becomes available.
                                            41

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Tangier Sound, Maryland/Virginia
Area with Low Probability for Adverse Effects, but effects data are needed.
                                           Region of Concern

                                           Area of Emphasis

                                           Low Probability
                                           for Adverse Effects
                                           Insufficient Data
                                          Additional state
                                           Assess me nti

                                           Ffch Advisories
                                           Impjiied Witen
                                           Threaten tit Waters
Summary:  The Tangier
Sound was characterized as
an Area with Low
Probability for Adverse
Effects because the excellent
spatial coverage of recent
sediment chemical
contaminant concentration
data indicated levels of
contaminants that were well
below those associated with
adverse effects on living
resources. Benthic
communities appeared fairly
healthy.
Results and Justification: The available data considered in making this characterization were
chemical contaminant concentration data for sediment and effects data (benthic community
assessments).  Even though there was no sediment/water toxicity test effects data, the excellent
spatial coverage of sediment contaminant data and the fairly healthy benthic communities
provided sufficient evidence that contaminant problems in the Tangier Sound are unlikely.

Caveats/Limitations: Future effects assessments involving collection of concurrent water and
sediment toxicity testing and chemical contaminant concentration data are needed to confirm this
initial characterization.

Additional State Assessments: In 1998, in assessing the conditions of its waters as directed by
the Clean Water Act, Maryland did not designate this area as impaired by chemical
contamination. Virginia designated a small creek in the southern portion of the sound as
threatened by chemical contamination. The Bay Program characterized the entire segment of this
river and not individual creeks.
                                            42

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Wicomico River, Maryland
Area with Insufficient or Inconclusive Data
                                        m
Region of Concern

Area of Emphasis

Low Probability
for Adverse Bfects
Insufficient Data
                                          Additional State
                                           Assessments

                                           Fish Advisories
                                           Impaiied Wjttrs
                                           Threatened Waters
                                                              Summary:  The Wicomico
                                                              River was characterized as an
                                                              Area with Insufficient or
                                                              Inconclusive Data because
                                                              available sediment chemical
                                                              contaminant concentration
                                                              data were insufficient both
                                                              spatially and temporally to
                                                              describe the conditions in the
                                                              river.  Fish tissue chemical
                                                              contaminant concentration
                                                              data were too old to be
                                                              representative of current
                                                              conditions, and no effects data
                                                              were available.  Additionally,
the available data did not include any pesticide data which is necessary to characterize a river in
an agriculturally dominated region.

Results and Justification: The available data considered in making this characterization were
chemical contaminant concentration data for sediment and fish tissue.  No effects data were
available. Available evidence indicated a low likelihood of adverse effects on living resources;
however, limitations in the data preclude a definitive conclusion.

Additional State Assessments: In 1998, in assessing the conditions of its waters as directed by
the Clean Water Act, Maryland did not designate the river as impaired by chemical
contamination.
                                            43

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Wye River, Maryland
Area with Insufficient or Inconclusive Data, with evidence of a low probability for adverse
effects on living resources.
                                           Region of Concern

                                           Area of Emphasis

                                           Low Probability
                                           tor Adverse Effects
                                           Insufficient Data
                                          Additional StJte
                                          Assessment:


                                           Fish Advisories
                                           Impaired Waters
                                           Threitened Waters
                                                             Summary: The Wye River
                                                             was characterized as an Area
                                                             with Insufficient or
                                                             Inconclusive Data because the
                                                             available data were
                                                             insufficient temporally and
                                                             spatially to describe the entire
                                                             river.

                                                             Results and Justification:
                                                             The available data considered
                                                             in making this characterization
                                                             were chemical contaminant
                                                             concentration data for
                                                             sediment, water, and fish
tissue and effects data (sediment and water toxicity tests). The sediment and water toxicity tests
data were conducted over several consecutive years and indicated a decline in toxicity in the later
years.  Although the workgroup members had a high level of confidence in the concurrently
collected sediment and water toxicity and chemical contaminant concentration data, the majority
did not think these data were spatially sufficient to describe the entire river. Data were
particularly lacking for the mainstem of the Wye River. Additionally, fish tissue data were too
old to be representative of current conditions.

Caveats/Limitations: The Wye River was classified as an Area of Insufficient Data by a
majority of the workgroup members. At  least one workgroup member disagreed with this
classification and felt that there were sufficient data to classify the Wye River as an Area with
Low Probability for Adverse Effects. Even though ambient toxicity data were limited to two sites
in one of the river's creeks, these data were collected at these sites for several consecutive years.
The water and sediment toxicity and elevated levels of nickel in the water observed in the earlier
years were not observed in later years, suggesting that toxicity in this area is not persistent.

Additional State Assessments: In 1998, in assessing the  conditions of its waters as directed by
the Clean Water Act, Maryland did not designate the river as impaired by chemical
contamination.
                                           44

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Upper Tidal York River, Virginia
Area with Insufficient or Inconclusive Data, with concern for a contaminant problem near the
confluence of the Pamunkey and Mattaponi Rivers.
                                          Region of Concern

                                          Area of Emphasis

                                          Low Probability
                                          tor Adverse Bfects
                                          Insufficient Data
                                         Additional State
                                         Assessments


                                       •  Fsh Advisoritc
                                       •  Impaired Waters
                                       Q  Threatened Waters
Summary:  The upper portion
of the York River below the
Mattaponi and Pamunkey
rivers was characterized as an
Area with Insufficient or
Inconclusive Data, (with  a
contaminant problem in the
upper portion of the segment).
Although the available data
indicated that the rest of the
segment had a low likelihood
of a chemical contaminant
problem, data were spatially
insufficient to make a definite
characterization.
Results and Justification: The available data considered in making this characterization were
chemical contaminant concentration data for water and sediment and effects data (water and
sediment toxicity and benthic community assessments). Water collected in the Pamunkey River
below West Point was found to be cause adverse effects to Bay organisms exposed to the water
in the laboratory. When compared to a total of 46 stations sampled in the 16 rivers Baywide, this
site ranked sixth for water toxicity. No water or sediment toxicity was observed upstream of this
site, although a metal (lead) was found at levels that indicate probable adverse effects on living
resources.  Even though chemical contaminants measured in the sediment in the rest of the
segment were at levels that are unlikely to cause adverse effects on living resources and benthic
communities appeared to be healthy, the spatial coverage of these data was not sufficient to
describe the entire segment.  Therefore, it was characterized as an Area with Insufficient or
Inconclusive Data.

Additional State Assessments:  In 1998, in assessing the conditions of its waters as directed by
the Clean Water Act, Virginia did not designate this area as  an impaired or threatened waterbody.
                                           45

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Lower Tidal York River, Virginia
Area with Low Probability for Adverse Effects
                                       | Region of Concern

                                       JQQ Area of Emphasis

                                       B Low Probability
                                       6=1 lor Adverse Effects

                                       f^TI Insufficient Data
                                         AdditionalStjte
                                          Aft t» mentf

                                       •  Fkh Advis«ri«t
                                       •  Impaired Waters
                                       Q  ThitJtened Wrttrs
Summary:  The lower portion
of the tidal York River (north
of Mobjack Bay) was
characterized as an Area with
Low Probability for Adverse
Effects because sediment
levels of contaminants were
below levels that are
associated with adverse
effects, and the water and
sediment was not toxic to Bay
organisms.
                                                             Results and Justification:
                                                             The available data considered
in making this characterization were chemical contaminant concentration data for water,
sediment, and fish tissue and effects data (water/sediment toxicity tests). The excellent spatial
coverage of recent sediment chemical contaminant concentration data indicated levels of
contaminants below those associated with adverse effects on living resources. Water and
sediment showed no significant toxicity when exposed to Bay organisms in the laboratory.  The
water and fish tissue chemical contaminant concentration data were too old to use in this
characterization.  The sediment chemical contaminant concentration data and supporting water
and sediment toxicity data demonstrated a consistent record that adverse effects are unlikely
throughout the segment.

Additional State Assessments: In 1998, in assessing the conditions of its waters as directed by
the Clean Water Act, Virginia did not designate any waterbodies in this segment as impaired by
chemical contamination. However, they did identify a small creek (Queen Creek) as threatened.
The Bay Program characterized the entire segment of this river and not individual creeks. Even
though there was  evidence for a site specific problem in a small creek, the overwhelming weight
of evidence indicated that, overall, this segment had a low probability for adverse effects.
                                           46

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Upper Mobjack Bay, York River, Virginia
Area with Low Probability for Adverse Effects
                                          Region of Concern

                                          Area ol Emphasis

                                          Low Probability
                                          for Adverse Bfects
                                          Insufficient Data
                                         Additional State
                                          Assessments

                                           Fiih Advisories
                                           Impaired Waters
                                           Threatened Waten
Summary: The portion of
Mobjack Bay, north of the
York River mainstem, was
characterized as an Area with
Low Probability for Adverse
Effects because good spatial
coverage of recent sediment
chemical contaminant
concentration data indicate
that levels of multiple
chemical contaminants were
well below those associated
with adverse effects on living
resources.
Results and Justification: The available data considered in making this characterization were
sediment chemical contaminant concentration data. Good spatial coverage of recent sediment
chemical contaminant concentration data indicated that levels of contaminants were well below
those associated with adverse effects on living resources. Although no effects data were
available, the sediment chemical contaminant concentration data conveyed a consistent record
that adverse effects are unlikely in this area.

Additional State Assessments: In 1998, in assessing the conditions of its waters as directed by
the Clean Water Act, Virginia did not designate this area as an impaired or threatened waterbody.
                                            47

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Lower Mobjack Bay, York River, Virginia
Area with Insufficient or Inconclusive Data, with potential contaminant problem in Back River
                                          Region of Concern

                                          Area of Emphasis

                                          Low Probability
                                          for Adverse Effects
                                          Insufficient Data
                                        Additional State
                                         Assessments

                                         Fish Advisories
                                         Impaired Waters
                                         Thitjttned Witirs
Summary:  The portion of
Mobjack Bay, north of the
York River mainstem, was
characterized as an Area with
Insufficient or Inconclusive
Data because data were
insufficient to describe the
segment. Throughout the
segment the spatial and
temporal coverage of chemical
contaminant chemical
contaminant concentration data
was poor, and effects data
were lacking.
Results and Justification: The available data considered in making this characterization were
chemical contaminant concentration data for sediment and water. No effects data were available.
The Back River is the site of two federal facility superfund sites.  Contamination is suspected
from metals (such as copper), polynuclear aromatic hydrocarbons (PAHs) and polychlorinated
biphenyls (PCBs). Copper was found in the water of Back and Poquoson rivers at levels that
indicate a high likelihood of adverse effects on living resources. Measurements for the other
chemical contaminants that are suspected to be problematic were unavailable. This segment will
be characterized once data from the federal facility superfund sites and data from ongoing studies
become available.

Additional State Assessments:  In 1998, in assessing the conditions of its waters as directed by
the Clean Water Act, Virginia designated the Poquoson River of this segment as a threatened
waterbody. This information will be considered in making a future characterization of this area
once all available data have been acquired.
                                           48

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V.    References

[1]    Chesapeake Bay Program.  1999. Targeting Toxics: A Characterization Report - A Tool
      for Directing Management and Monitoring in the Chesapeake Bay's Tidal Rivers - A
      Technical Workplan.  U.S. EPA CBPO, Annapolis, Maryland.

[2]    Chesapeake Executive Council.  1994.  Chesapeake Bay Basinwide Toxics Reduction and
      Prevention Strategy. Annapolis, Maryland.

[3]    Chesapeake Bay Program.  1999. 1999 Chesapeake Bay Basin-wide Toxics Loading and
      Release Inventory.  U.S. EPA CBPO, Annapolis, Maryland.
                                        49

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VI.   Appendix A:  Scientific and Technical Advisory Committee Review of
       Characterization
June 1, 1999

Mr. Robert Summers
Chair, Toxics Subcommittee
Maryland Department of the Environment
2500 Broening Highway
Baltimore, MD 21224

Dear Mr. Summers:

In response to the request from the Implementation Committee, the Scientific and Technical Advisory Committee
(STAC) conducted an expedited, independent technical review of the Toxics Subcommittee's publication Targeting
Toxics: A Characterization Report - A Tool for Directing Management and Monitoring Actions in the Chesapeake
Bay's Tidal Rivers, and its Technical Workplan.  The results of this review process are described in the attached
report.

The review panel for this effort, chaired by Dr. Jonathan Phinney from the Center for Marine Conservation, was
charged with three tasks: (1) evaluate the protocol used for the characterization, and its utility as a management tool,
(2) determine of the protocol was properly implemented, and (3) recommend how this information can be more
effectively communicated hi the future. Each of these charges are addressed in detail in the attached report. A
presentation and discussion with the subcommittee of the findings of the review panel can be arranged, if requested.

In general, the review panel found the protocol used for this toxics characterization, and its implementation given
the available data sets, to be appropriate. They commended the Toxics Subcommittee for pulling together so many
disparate datasets to be effectively used for a single purpose. However, despite the large number of data sets used in
the characterization, significant information gaps exist for the Bay's tidal rivers. As such, the reviewers recommend
that the results of this characterization be used primarily to direct future toxics research and monitoring efforts.

The attached report recommends some specific changes to the characterization report and its technical workplan.
STAC requests that the Toxics Subcommittee respond to those recommendations, identifying how they were
implemented or clarifying why such changes were not feasible and/or appropriate, by June 18, 1999.  After the
responses are received, STAC will submit the technical review report to the Implementation Committee.

STAC appreciates the opportunity  to participate in the review of the toxics characterization report. If you have any
questions or need further information, please feel free to contact myself or Caryn Boscoe, STAC Coordinator.

Sincerely,
Richard L. Jachowski
Chair, Scientific & Technical Advisory Committee
CC:    Kelly Eisenman, TSC Coordinator
       Carrie McDaniel, TSC Fellow
       Joe Winfield, Regional Focus Workgroup Chair
                                                A-l

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                                 Technical Review

                                         of

                 Targeting Toxics: A  Tool for Directing Management and
                 Monitoring Actions in the Chesapeake Bay's Tidal Rivers

                         Public Report & Technical Workplan


                                    June 1,1999
                  Conducted by the Scientific and Technical Advisory
                      Committee to the Chesapeake Bay Program
Review Panel Members

Jonathan Phinney (chair); Center for Marine Conservation
Richard Coffin; Naval Research Laboratory
Dan Dauer; Old Dominion University
Dennis Suszkowski; Hudson River Foundation
Caryn Boscoe (coordinator); Chesapeake Research Consortium

                                        A-2

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Introduction

In April 1999, the Chesapeake Bay Program's Implementation Committee requested that the
Scientific and Technical Advisory Committee establish a review panel to conduct an expedited,
independent, technical review of two publications produced by the Toxics Subcommittee:
Targeting Toxics: A Characterization Report - A Tool for Directing Management & Monitoring
Actions in the Chesapeake Bay's Tidal Rivers and the characterization's Technical Workplan.
The ad hoc review panel was charged with the following three tasks:

1.      Evaluate the scientific merit of the protocol and criteria used in the characterization of
       any designated region of the tidal Chesapeake, as detailed in the 1999 Technical
       Workplan. Address the suitability of this protocol as a management tool.

2.      Provide  an assessment of whether the protocol was properly used to categorize tributary
       segments described in the workplan and the report,

3.      Recommend how future reports on characterization of contaminant-related impacts can
       most effectively and accurately communicate information about habitat status.

Foremost, the Toxics Subcommittee and its Regional Focus Workgroup is to be commended for
weaving together the many databases used in the characterization into a centralized, useable
system. Formatting so many disparate sources such that they can be used to address a single
problem is a significant challenge. In addition, the successful coordination of the many agencies
and individuals  involved in the Workgroup's development of the protocol and the
characterizations is a major accomplishment in itself.

The data available for use in the development of this characterization posed a considerable
challenge to the Regional Focus Workgroup. Information was collected from a wide variety of
research and monitoring efforts which tested for different compounds at different time scales,
using a range of sampling protocols.  The result of this collection is a dataset with uncoordinated
and incomplete spatial and temporal (historic and seasonal) coverage. As such, this toxics
characterization has limitations in the level of detail at which it can classify toxicity, as well as
identify sources and primary  contaminants in a system. This paucity of data should be
emphasized in the report, both for an accurate understanding of the limitations and to encourage
further, coordinated monitoring efforts. The review panel makes some specific recommendations
about future research and monitoring later in this report.

Review Process

Reviewers were chosen to represent expertise in a range of toxicological disciplines. Following
the review of the two documents and the datasets used by the Regional Focus Workgroup to
characterize the Chester River segment, the review panel submitted written comments to Caryn
Boscoe, who drafted the initial report. Based on three group discussions of the pertinent issues,
reviewers made revisions to two subsequent redrafts before completion of the final report.
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1. Scientific Merit of the Protocol and Criteria

In general, the review panel found the protocol used in the Technical Workplan to be suitable for
the limited dataset presently available, and should be considered a first attempt to characterize
the toxicity in the Bay's tidal rivers and to direct future monitoring efforts.  The characterization
protocol presented a logical series of steps that involved identifying and compiling relevant data,
interpreting the data in light of established endpoints, and then characterizing river segments into
qualitative categories.

       Categories:  Given the present level of data and information, the four categories used in
       the characterization are appropriate: (1) Region of Concern, (2) Area of Emphasis, (3)
       Area with Low Probability for Adverse Effects, and (4) Area with Insufficient or
       Inconclusive Data. The review panel recommends that descriptions and figures
       (particularly Figure 3) for each of the segments in Category 4 specify whether the data
       available were insufficient or inconclusive. Insufficient data requires more general
       monitoring, while inconclusive data calls for focused research and/or monitoring.

       Endpoints: The endpoints, or thresholds, used to characterize the level of contamination
       in each segment were generally appropriate.  Those used to evaluate water quality were
       found to be conservative and appropriate guidelines. The thresholds for sediment
       analyses are currently a subject of scientific debate, but appropriately based on current
       information.

       Management Tool: As a management tool, the protocol is useful as an initial assessment
       of the Bay's tidal tributaries and provides a good model for other estuary programs to
       utilize.  It summarizes existing data and sets up priority segments for future analysis.  The
       greatest strength of the characterization may be its role as a scientifically sound means to
       identify future sites and issues for study and monitoring, and should be used to direct
       upcoming efforts.

       The current characterization presents two potential problems related to management
       actions and public interpretation of the results: (a) it may overstate problems because the
       relationships between cause and effect in the segments are not well established, or (b)
       they may understate problems because data are limited or lacking altogether.  These
       information gaps limit the ability of the characterization to identify specific locations
       and/or contaminants which require regulation or management. This qualification should
       be considered when using the  characterization as a management tool.

2. Protocol Implementation

The reviewers examined the datasets available from the Chester River as a case study for the
implementation of the characterization protocol.  Based on this information, the reviewers felt
that the consensus process utilized by the Workgroup successfully implemented the criteria and
decision rules described in the technical workplan. The panel would like to reemphasize a point
made in the workplan, that making a characterization is not a standardized or reproducible
process. Rather, the Workgroup members had to apply their best professional judgement and
group consensus in the characterization of each of the segments.
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The review panel recommends the following revisions to the Technical Workplan and Public
Report:
•      The segment profiles in the public report make statements about the toxicity levels in the
       tributaries which are inappropriate and/or misleading, particularly when based on a
       limited number of presumably uncoordinated toxicity tests. For example, the Chester
       River profiles states "The sediment in the upper portions of the Chester River was found
       to be highly toxic...to Chesapeake Bay organisms..." The panel recommends that
       descriptors such as "highly toxic" be changed to more neutral language (e.g. "adverse
       effects") unless detailed definitions are included for such classifications.
•      Areas with Low Probability for Adverse Effects: the report should emphasize that just
       because there is not a chemical contaminant-related problem does not mean that the
       tributary is healthy, requiring no further management or restoration efforts. Other
       environmental factors, such as low dissolved oxygen, may impact chemical fates and
       transport times, having future implications for the segment. A notation of this caveat
       could also be included in the figures (especially Figure 3).
•      Include more information about the datasets used in the characterization. For example:
       (1) Discuss the temporal coverage of the water column data.  Were samples collected
       seasonally? Monthly? Coordinated with precipitation events? (2) What does the toxicity
       data consist of? What species are used?  What are the degrees of toxicity?
•      The public report mentions the "Workgroup's confidence" or "level of confidence."
       From a scientific perspective, the report should clarify the level of uncertainty, where
       possible, in making a decision about the potential toxic effects in a segment, thus
       illustrating the possibility of an incorrect (either positive or negative) classification.
•      The major purpose of the characterization is to prompt action when problems are found -
       or yet to be found.  There  is very little detail about the types of actions that might be
       taken. Though it may be premature to describe detailed remedies, it is likely that ongoing
       inputs will be problematic in areas of concern. What will be done to investigate the
       sources of the pollutants?  If multiple sources are discovered, then some relative
       significance will have to attached to the various sources.  If this is the case, loadings will
       have to quantified and models may be necessary to link the loads with observed
       conditions in water, sediment and biota.  Is modeling planned? Will sources be
       quantified? Will the existing data support model development?
•      Pollution Prevention is stated as an option, however, this form of contaminant reduction
       may not be appropriate to deal with problematic compounds like PCBs and DDT ~
       chemicals that were banned years ago. What about TMDLs or other regulatory tools?

3. Future Research and Monitoring

As stated earlier, the greatest utility of the toxics characterization is to direct and influence future
chemical contaminant research and monitoring programs. It is clear from the inconsistencies in
the present dataset that a focused, coordinated monitoring program would allow a much more
detailed, comprehensive analysis  of the toxicity problems in the Chesapeake Bay ecosystem.
The following are a few specific recommendations for consideration in future monitoring and
research programs, in anticipation of an updated characterization project.
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•      Identifying those contaminants which have significant adverse effects on living resources
       would allow the prioritization of monitoring and restoration efforts.  Genetic and tissue
       toxicity assays can demonstrate the contaminant effects at multiple levels of the food web
       and be beneficial in setting priorities. (See References)
•      Continuing studies on the impact of low level, long-term exposure to ambient toxicity
       should be encouraged.
•      Future work for assessing habitats in the segments would benefit from a more thorough
       analysis of spatial and seasonal variations in contaminant concentrations and the
       contaminant turnover time. For example, sampling should be coordinated with pesticide
       applications in the spring.
•      Repeated measurement of chemicals which are no longer in use (e.g. DDT) may be of
       limited utility for regulation and prevention, particularly in areas where new introductions
       are unlikely. If initial surveys demonstrate that these chemicals are not present or in
       harmless amounts, monitoring should be shifted to incorporate chemicals and pesticides
       currently used in the watershed.
•      As data availability improves, the guidelines and criteria used for the characterizations
       should also be updated. For example, EPA's Acute and Chronic Water Quality
       Guidelines are outdated and do not take into account advances in toxicity assessment
       such as AVS measurement of sediment toxicity, speciation measurements, and synergism
       between toxicants. The Guidelines should be used as a first assessment of a potential
       problem that could require follow-up speciation and toxicity tests.

•      Public health implications of chemical contaminants would seem to be of paramount
       importance, and should have greater emphasis in future characterizations. Specifically,
       (1) highlight fish tissue data and associated health advisories in future reports, (2) in
       conjunction with state organizations, conduct a Bay-wide assessment of contaminants in
       edible species, with an emphasis on organics, (3) considering the movement of
       contaminants in fish, reassess the characterization of the mainstem Bay as free of toxics
       impacts.

Textual Comments

Reviewers identified specific questions and comments about the text of the documents,  detailed
below.

Overview comments / questions

•      Throughout the report, the distinction between "exposure" and "effects" is unclear.
       Recommend changing to "concentration" and "toxicity" (or other appropriate terms).
•      How will PCBs be quantified? The Workplan states that arochlors and congeners will be
       summed. Will the 18 or so congeners be combined to  obtain a measure of total PCBs? If
       so, this total will likely be a factor of 2 too low. Why was the Workgroup's confidence in
       using a total PCB threshold...fairly  low?
•      Are there other endpoints that have management implications that could be used in the
       characterizations?  For instance, is dredged material analyzed in relationship to any toxics
       endpoints? If so, these endpoints would be useful to include.  The more endpoints that
       have specific management implications, the better.
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Page-specificcomments / questions
•      Pg 2 para 2 bullet 1. Change sentence to read Better identify and conduct risk assessment
       analysis in the Areas of Emphasis. As written, "implement necessary pollution prevention
       action" is premature given that there is little data available in some areas of emphasis.
       More direct field studies would be the logical next step.
•      Pg 4: the mainstem of the Bay is not characterized because contaminant levels are low.
       The sentence about technique development implies that there are possible effects in the
       mainstem (or also in the tributaries) which can not be detected.  Is this statement based
       upon caution or suspected cases in the data set where toxicity effects were found but no
       measured levels of contamination?
•      Pg 4, bottom: "... spatially or temporally insufficient.... inconclusive... data.." A bit
       vague and never resolved. Possibly this is an outcome of the shear size and complexity
       of the task at hand.
•      Pg 5: "... limited or no evidence for a relationship..." "... Strong evidence for a linkage..."
       Vague.
•      Pg 5 para 4: drop "pollution prevention actions" replace with better characterization of
       toxicity using speciation, risk assessment, other tools. See explanation first bullet.
       Pg 6 para 1: "Chemical contaminants entering the tidal rivers tend to get trapped...." This
       indicates that a mass balance of input relative to dilution from river and tidal energy has
       been accomplished. If this has not been done this needs to be restated.
•      Pg 7 para 1: Table 1 need to have sources embedded in a legend, so the reader doesn't
       have to interpret Appendix B. For instanced, water column contaminant data
       concentrations could include EPA's Acute and Chronic Toxicity Guidelines.
       Pg 8 para 4, line 2: What was the QA/QC on data going back to 1976? For trace metals,
       "clean techniques" were developed during that period and not implemented for another 10
       years or so. There should be added emphasis on screening of data sets.
•      Pg 9 para 2, line 2: "water exposure" should be changed to "water concentration."
       Exposure is a nebulous term and the data are generally reported in concentration units.
•      Pg 9 para 2 line 4: Define "adequate spatial coverage": 50 % of tributary? other?
•      Pg 10 para 2 line 5: "no random benthic sampling data were available for Virginia
       waters.." A benthic monitoring program has been in place in Virginia since 1996.
       Statement in the report needs to clarify that the data from this program were just not used
       in the characterization.
•      Pg 11, bottom: Last sentence about "absence of data" and inference from expectations is
       troublesome.
•      Pgs  12-13: List the actual data sets used in the guidelines. It is done in some sections
       such as water Column Concentration-(e.g. EPA aquatic life criteria) ,but not Bottom
       Sediment or Finfish/Shellfish.  Just listing the Chesapeake Bay Program Toxic
       Databases is not enough; list NOAA's ER-L/ER-M threshold document and others.
•      Pg 13: benthic B-IBI criteria conflict with those in Appendix B, page 10.
•      Figure 6 shows locations of benthic community samples used in the report.  There were
       hundreds of EMAP locations that are not indicated here. Were EMAP data used?  In
       1996 the Virginia Benthic Monitoring Program began random sampling at 100 locations
       each year. There are 200 random Virginian locations that were available for the period
       1996-1997. Were these data used?
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References

Ray, S., Dunn, B.P., Payne, J.F., Fancey, L. and Belands, P. 1991. Aromatic DNA-carcinogen
adducts in Beluga whales from the Canadian Arctic and Gulf of Lawrence. Mar. Pollut. Bull. 22:
392-396.

Stein, J., Collier, T.K., Reichert, E., Casillas, T., Horn, T. and Varanasi, U. 1992. Bioindicators
of contaminant exposure and sublethal effects: studies with benthic fish in Puget Sound,
Washington. Environ. Toxicol. Chem. 11: 701-714.

Reichert, W.L. and French, B. 1994. 32P-Postlabeling protocols for assaying levels of
hydrophobic DNA adducts in fish. NOAA-NWFCS Tech Memo-14.
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Chesapeake Bay  Program
410 Severn Avenue, Suite 109, Annapolis, Maryland 21403 • 410-267-5700 • FAX 410-267-5777- Toll free 800-968-7229

       June 15, 1999

       Richard L. Jachowski
       Chair, Scientific and Technical Advisory Committee
       U.S. Geological Survey
       11410 American Holly Drive
       Laurel, MD 20708-4015

       On behalf of the Toxic  Subcommittee, I would like to thank you for coordinating such a comprehensive
       STAC technical review of the toxics characterization effort The review panel's
       in depth review of the scientific merit of the protocol and criteria used in the characterization, the
       application of the protocol, and communication of the results has helped us to strengthen this initial
       characterization and will provide insight on how to improve the characterization in future updates.

       Attached is our response to the  STAC review which details how we have responded to the
       recommendations and issues that were raised. We would be happy to meet with the STAC review panel
       and the entire Committee to discuss the review in more detail if desired. You will note throughout our
       response, that we highlight several areas where follow up discussions and further coordination with
       STAC would be beneficial, particularly in acting on the review panel's recommendations for future
       research and monitoring.  We would like to continue this dialogue with the broader scientific community
       as we undergo reevaluating and revising the 1994  toxics strategy this year, particularly at the upcoming
       "science forum" in September.

       The reviews that the STAC has conducted over the years on key Toxics Subcommittee products and
       budget proposals have been invaluable. We look forward to continuing these discussions and
       interactions with the STAC and the broader scientific community as we plot our course for the year 2000
       and beyond.
                                                                               — ™"~ ••(*•*•*« *^f w i_i4ji QI y
                                                                             Mail code 3201
                                                                     1200 Pennsylvania Avenue NW
                                                                         Washington DC 20460
Sincerely,                                                      .. 0 __.. ..
                                                               U.S. EPA Headquarters Library
                                                                      Mail code 3201
                                                               1200 PI
Bob Summers
Chair, Toxics Subcommittee
Maryland Department of the Environment

Attachment
cc:     Jonathan Phinney, Chair of Review Panel/Caryn Boscoe, STAC
                                                   A-9

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            Toxics Subcommittee Response to the STAC Technical Review of
           Targeting Toxics: A Tool for Directing Management and Monitoring
                       Actions in the Chesapeake Bay's Tidal Rivers
                          Public Report & Technical Workplan

       This report represents the formal response from the Toxics Subcommittee to the
Scientific and Technical Advisory Committee (STAC) review report of the characterization
(Attachment A). The STAC recommendations are listed under heading topics used in the STAC
review report in the order they appear in the review report. The Toxics Subcommittee's response
follows each recommendation and includes a combination of actions (in bold text) and further
explanations. The "workgroup" refers to the  Toxics Subcommittee's Regional Focus Workgroup
which was charged with conducting the toxics characterization.
Introduction
RE:    Data Limitations: "This paucity of data should be emphasized in the report, both for an
       accurate understanding of the limitations and to encourage further, coordinated
       monitoring efforts."

       Agreed. We appreciate that the review panel recognized one of the more important
       limitations to our efforts. It is important to emphasize that the database used in this
       characterization is from a wide range of research and monitoring programs [sic:
       uncoordinated efforts] that provide inadequate descriptions of the presence of
       contaminants and their potential or actual impacts for much of the Bay [sic: incomplete
       spatial and temporal (historic and seasonal) coverage]. This characterization is limited in
       the level of detail at which it can classify problems related to contamination [sic:
       toxicity]. It should be apparent that a better understanding and more clear picture of the
       problems can only be provided by enhanced and coordinated monitoring efforts at all
       levels within the Chesapeake Bay Program. This limitation is clearly stated in the
       technical workplan (Section III.A.5. Data Limitations and Section VI. Recommendations
       for Future Updates). We have added the following section in the public report
       "Limitations of Data" (Section II) to ensure that this limitation is clearly stated:
       "Limitations of Data: It is important to  note that, to date, there is no Baywide  monitoring
       program designed to characterize toxics  conditions in the Chesapeake Bay's tidal rivers
       on the scale necessary to perform comparable assessments of all rivers.  Information used
       for this characterization was collected for a wide  variety of studies that were conducted
       for different purposes. The result of this collection is a dataset with uncoordinated and
       incomplete spatial and temporal coverage. The workgroup was faced with the  challenge
       of piecing together these different datasets and  developing a consistent set of decision
       rules for how to interpret this information in making a characterization.  As such, this
       characterization has limitations in the level of detail at which it can characterize toxic
       effects on the Bay's living resources. Through increased funding, intensified
       coordination with federal and state toxics monitoring and research efforts, and  intentional
       collaboration between Bay Program signatory states at the governmental and academic
       level to address Bay-wide issues, the gaps in data coverage will be filled." We have also
       added the following sentence in Section VI Recommendations: "Only through
       increased funding, intensified coordination with all Federal and State toxics monitoring
       and research efforts, and intentional collaboration between the Signatory states at the

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       governmental and academic level to address Bay-wide issues, will the gaps in data
       coverage and gaps in our knowledge of the distribution and extent of toxic effects be
       filled."

/. Scientific Merit of the Protocol and Criteria
RE:   "... should be considered a first attempt to characterize toxicity in the Bay's tidal rivers
       and to direct future monitoring efforts."
       Agreed. Prior to future updates to the characterization, an accounting of the "lessons
       learned" would be useful for future refinements and the next characterization to be
       performed in 3 years (see 1994 Chesapeake Bay Basinwide Toxics Reduction and
       Prevention Strategy) or for periodic updates as new data become available (an alternative
       strategy to triennial updates).
       "The review panel recommends that descriptions and figures ... for each of the segments
       in Category 4 specify whether the data available were insufficient or inconclusive."
RE:
       We agree that distinguishing between areas with insufficient data versus areas with
       inconclusive data is important. Initially, the Regional Focus Workgroup (hereafter,
       workgroup) was working with only the category of "insufficient" and found that in some
       cases it was difficult to classify a segment because the data, although of adequate
       spatial/temporal coverage, were considered "inconclusive" or conflicting for one or more
       reasons. "Insufficient" was considered just too little data to interpret for the spatial scale
       of the segment.  In developing a consensus, the workgroup "lumped" these two categories
       together because the best professional judgement was that any additional monitoring or
       research in these areas would have to be directed at answering one question: what is the
       level of impairment due to toxics, if any? The workgroup has not developed specific
       definitions or decision rules to distinguish segments with insufficient data from segments
       with inconclusive data and therefore cannot provide extra detail on the map. We have
       clearly indicated when data were spatially or temporally insufficient versus
       inconclusive in the summary section of each segment profile in the public report.

       It is obvious that the two strategies suggested by STAC ("more general monitoring" vs.
       "focused research and/or monitoring") are good approaches for resolving the
       classification uncertainties.  The Toxics Subcommittee will continue to use the more
       detailed information in the segment profiles and the data used to make the
       characterizations to set its characterization priorities in the Areas with Insufficient
       or Inconclusive Data. It may be appropriate for STAC and the Toxics Subcommittee to
       work together in the process of setting specific objectives for the research and monitoring
       programs. That is, the Toxics Subcommittee should recognize the differences among the
       Areas with Insufficient or Inconclusive Data and decide the appropriate monitoring
       strategy with STAC review so that the uncertainties can be resolved  at a management and
       scientific level, respectively.
RE:    Endpoints
RE:
       Concur.
       Management Tool
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1st f   RE: "model for other estuary programs" and "greatest strength of the characterization
       may be its role as a scientifically sound means to identify future sites and issues for study
       and monitoring."

       Concur.

2nd ^   (a) "two potential problems related to management actions"
       We agree that the "greatest strength of the characterization may be its role as a
       scientifically sound means to identify future sites and issues for study and monitoring,
       ...". We also agree that there are limitations in how this characterization can be used for
       targeting management activities. We believe that this initial characterization can serve as
       a valuable planning tool to help the Bay Program to better target its voluntary
       management actions in the watershed. We have always pursued two goals:   to improve
       our understanding of toxic impacts in the Bay, while concurrently acting with the
       knowledge we have now to ensure that we are reducing and preventing chemical
       contamination in the Bay.  As our understanding increases, we will be able to better target
       our management actions. This characterization will allow the Chesapeake Bay Program to
       determine the areas in which to focus its voluntary pollution prevention and reduction
       efforts and the areas in which to focus its preservation/conservation efforts.  For example,
       in the Areas of Emphasis where point source loadings of chemicals of concern are
       substantial (based on the recently published 1999 Chesapeake BayBasinwide Toxics
       Loading and Release Inventory) we could target businesses in those watersheds for
       further voluntary chemical reductions through the voluntary pollution prevention
       program, Businesses for the Bay. The characterization gives the State/District partners
       base information to allow them to conduct the more site specific analysis and source
       assessment studies necessary for implementing regulatory programs called for in  the
       Clean Water Act.

       We agree that we need to clearly state the utility of this characterization, highlighting its
       primary value as a tool for targeting monitoring and carefully describing how it can be
       used for targeting voluntary management activities. To clarify the utility of the
       characterization, we have added the following paragraph into the public report
       (Section III: What will be done with this characterization effort) and in Technical
       Workplan (Section V. Implications of the Characterization): "The primary value and
       utility of the characterization is in identifying areas that need additional monitoring and
       assessment to better characterize the status of toxic effects on living resources inhabiting
       those areas. This characterization can also serve as a planning tool to help the
       Chesapeake Bay Program determine the areas in which to focus its voluntary pollution
       prevention and reduction efforts  and the areas in which to focus its voluntary
       preservation/conservation efforts. The characterization gives the State/District partners
       base information to allow them to conduct site specific analysis and source assessment
       studies which may be necessary before regulatory actions can be taken."
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 2nd f  (b) RE: "overstate problems"
       The workgroup made every effort to be conservative in characterizing an area as an Area
       of Emphasis. However, due to the limitations of the data, it is possible that some
       problems may be overstated either in degree or extent of contamination. Uncertainty in
       the characterizations has been detailed in the caveats in the segment profiles in the public
       report. It is important to note that the burden of proof for an Area of Emphasis does not
       require a demonstrated cause and effect relationship. It may be argued that, with few
       exceptions, direct cause and effect relationships are impossible to define when working
       with ambient exposure and effects data. Only where there are site-, contaminant- or
       effects-specific studies with the objective to identify causative agents and to confirm their
       actions against target species, populations or communities is there a chance for some
       level of confidence in defining causality. We intentionally restricted our efforts to
       looking at ambient data and not data from known "hot spots" for contaminants or effects
       to ensure that we were characterizing an entire segment rather than letting a known
       problem (hopefully under responsible management attention such as the implementation
       of TMDLs or remediation efforts) drive the classification for a segment. Also, we "raised
       the bar" for our use of the "disputed" thresholds or benchmarks to reduce the likelihood
       of overstating problems because of the concern for unwarranted alarm or management
       action.

2"^    (c)     RE:   "understate the problem"
       Agree. This is an issue that the workgroup struggled to address. We are highly
       concerned about overlooking a problem where current data "suggest" that there is no
       problem and giving the managers and public a false sense that the entire segment is clean
       or safe from either a natural resources, habitat, or human health perspective. We have
       addressed any limitations or caveats in the characterizations in the segment profiles
       in Section tV of the public report.

2.  Protocol Implementation
RE:    CASE STUDY: Chester River "...the reviewers felt that the consensus process utilized
       by the Workgroup successfully implemented the criteria and decision rules described in
       the technical workplan."

       Concur.

Bullet 1:      "The panel recommends that descriptors such as 'highly toxic' be changed to
             more neutral language (e.g. 'adverse effects') unless detailed definitions are
             included for such classifications."

       Agree that a more globally understood term or terms be used throughout the report to
       describe results of toxicity tests.  The author of the source document for these data used
       words such as "highly toxic" and "low to moderately toxic" to indicate the severity of
       toxicity observed based on the number of toxicity tests and endpoints showing toxic
       effects. Since these words are not in and of themselves descriptive, we have replaced
       them  with text which describes that an adverse effect occurred and gives an
       indication of the severity of toxicity. An example of the change in wording is: "the

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       [sediment/water] was found to cause adverse effects on Chesapeake Bay organisms
       exposed to the [sediment/water] in the laboratory. In laboratory studies, sediment from
       [location] was more toxic to animals that live in the sediments than almost all other
       sediments tested in the Bay (ranking third [for example] out of 46 stations sampled in 16
       rivers Baywide)." Where the author provided inferences regarding what chemical
       contaminants may be contributing to the toxicity, we have provided that information as
       well.  For those people wanting more detail on the toxicity test results, the number of
       endpoints significantly different from the controls, the toxicity index, etc. we have
       included the following reference in Section IV.  For More Information of the public
       report: "For electronic copies of the data evaluated by the workgroup, please refer to the
       Bay Program Home Page at http://www.chesapeakebay.net or contact the Bay Program
       Office at 1-800 YOUR BAY. Note that where feasible, links are made to the actual
       datasets or summary reports/abstracts."

Bullet 2:      "... the report should emphasize that just because there is not a chemical
              contaminant-related problem does not meant that the tributary is healthy..."

       Agreed, but assessing impacts due to non-anthropogenic substances was beyond our
       charge-of-duties and beyond our capacity to evaluate with the available data. We did take
       into consideration in situ effects measures where low dissolved oxygen levels may have
       been a causative factor for reduced benthic indices because the data were available.  It is,
:       however, very important to describe other factors that can influence the survival of living
       resources by affecting the toxicity of substances in the environment. We have
       mentioned this in the Section III.A.5 of the Technical Workplan.

Bullet 3:      "Include more information about the datasets used in the characterization..."

       Agree that the more detailed information regarding the purpose of the study, the sample
       design, the species used in toxicity tests, etc. is necessary to folly evaluate the
       characterization. It was beyond the Regional Focus Workgroup's charge to develop a
       narrative summary of the numerous datasets it evaluated in conducting the
       characterization. However, we understand that many users of the characterization are not
       as familiar with  the data as the workgroup is and need background information. The
       characterization reports, supporting data, and references for all data evaluated will be
       published on the Chesapeake Bay Program homepage. Where feasible, we will provide
       links from the reference table to the actual studies to ensure that the more detailed
       information about the study can be accessed. We have indicated this in Section IV.
       For More Information of the public report We are hopeful that we will have the
       cooperation of the scientific community in making their datasets, reports, and abstracts
       available via the web.

Bullet 4:      "The report should clarify the level of uncertainty, where possible, in making a
              decision  about the potential toxic effects in a segment,..."

       Agree that the level of uncertainty in making a characterization is important to stress in
       the report.  The level of confidence by the workgroup is an expression of the magnitude,
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       frequency and extent (or distribution) of the contaminants or effects measured. The level
       of confidence cannot be numerically quantified in the sense of a quantitative risk
       assessment process for ambient concentration gradients about a source, but it can be
       expressed in terms of how convincing or compelling the data were when carefully
       weighed and subjected to the best professional judgement by the individuals and
       confirmed through a consensus process. The Regional Focus Workgroup has clearly
       indicated the overall uncertainty in the characterization effort in the technical workplan
       (Section A.5. Limitations of Data, B.6. Limitations in Data Interpretation, VI.
       Recommendations for Future Updates to Characterization) and in the way the decision
       rules were set up to account for uncertainty in the data and thresholds used (see Section
       B.2. Decision Rules for Interpreting Data and Appendix B.). The workgroup's level of
       uncertainty in individual characterizations is stated in the limitations and caveats section
       of each of the segment profiles. To ensure that uncertainty is more directly addressed
       in the public report, we added a statement in the first paragraph of Section IV to
       point the reader to the caveat/limitations section of each of the segment profiles for
       more description on the level of uncertainty for each characterization.

Bullet 5:     "What will be done to investigate the sources of pollutants?"

       Agree in concept, however, identifying sources and recommending actions to take in
       certain areas is beyond the workgroup's charge-of-duties and greatly exceeds the level of
       effort available for this report. Actions can be taken on two fronts; 1) regulatory and 2)
       voluntary. To recommend regulatory actions may overstep our relationships with the
       States.   Voluntary programs underway can benefit from some of the information in the
       characterization and more detailed segment profiles. For example, for voluntary
       programs in an area classified as an Area with Low Probability for Adverse Effects, the
       participants can encourage preservation and  good stewardship of an impacted resource.
       Point and nonpoint source chemical contaminant loads to the Bay and its major tidal
       rivers have been quantified in the 1999 Chesapeake Bay Basinwide Toxics Loading and
       Release Inventory. The characterization, coupled with the loadings inventory, will
       provide initial information to enable managers, scientists, and stakeholders to target their
       toxics reduction and prevention activities towards specific source categories and
       chemicals.  Further assessments may be necessary to elucidate the problems and sources,
       before regulatory actions can be taken. With respect to the data supporting model
       development, only the modelers will know if the data meet their assumptions and needs
       (See related responses in Section 1.  Scientific Merit re: management tool, Bullet 6 of this
       section, Section IV. Page Specific Textual Comments, Bullet 1).
Bullet 6:
'What about TMDLs or other regulatory tools?"
       It was beyond the scope of the Regional Focus Workgroup to determine the specific
       activities and remedies that should be taken in each of the characterized segments. The
       report outlines general actions that the Chesapeake Bay Program can take in each of the
       four categories which originated from the 7994 Chesapeake Bay Basinwide Toxics
       Reduction and Prevention Strategy.  We agree that pollution prevention activities will not
       address contamination problems that are due to historically used chemicals that are
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       banned, yet persistent. Regulatory programs at both the federal and state level are
       necessary to address the intractable problems of sediment contaminated with historically
       used persistent bioaccumulative chemicals.  The Chesapeake Bay Program's role in
       toxics management is to supplement the regulatory programs with voluntary actions
       where necessary. We believe it will take a combination of both regulatory and voluntary
       actions to effectively address chemical contaminant impacts in the Bay. It is up to the
       Chesapeake Bay Program and its partners to determine the next steps that need to be
       taken to prevent and reduce chemical contaminant impacts in the Bay and to protect and
       conserve areas in the Bay from future harm.

3. Future Research and Monitoring
       Many of the recommendations for future research and monitoring were incorporated into
       the FY2000 Request for Proposal for Toxics Subcommittee funding for chemical
       contaminant characterization efforts.  As part of the Toxics Strategy Reevaluation and
       Revision, the Bay Program will hold a forum in September with the scientific community
       to discuss many of these issues and recommendations.  We are working with STAC to
       ensure that this dialogue with the scientific community continues so that we can develop
       actions to deal with these information gaps in order to better target our management
       actions.

Bullet 1:      "Genetic and tissue toxicity assays can  demonstrate the contaminant effects..."

       The endpoints suggested must be shown to be important and relevant to the stakeholders.
       That is, resource managers and the public should fully understand the meaning of the
       endpoints for genetic and tissue toxicity assays. For resource managers, these endpoints
       must relate to some decision point in their regulatory programs.

Bullet 2:      "Continuing studies on the impact of the low level, long term exposure to ambient
              toxicity should be encouraged."

       Concur.  The Toxics Subcommittee is working closely with the NOAA Chesapeake Bay
       Environmental Effects Committee's Toxics Research Program to ensure that the funded
       research addresses management questions. Although the focus of the research program
       for the next 5 years is on contaminated sediment in the three Regions of Concern, impacts
       from low levels will also be addressed.  It may be necessary for STAC and the Toxics
       Subcommittee to partner with other such research programs to leverage additional funds
       to more thoroughly address this issue.

Bullet 3:      "...more thorough analysis of spatial and seasonal variations..."

       Concur.  Although resource limited, a subset of this problem is addressed in the FY2000
       Request for Proposals for Toxics Subcommittee funding which solicit projects to assess
       the effects of pesticides in the Eastern Shore rivers by coordinating sampling with
       pesticide applications in the spring.
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Bullet 4:      "Repealed measurements of chemicals which are no longer in use., .may be of
              limited utility..."

       Concur. However, it is important to note that some of these banned chemicals (i.e.,
       PCBs and chlordane) are continuing to have an impact and accumulate in aquatic life,
       resulting in fish consumption advisories and potentially other problems.

Bullet 5:      "As data availability improves, the guidelines and criteria used for
              characterizations should also be updated."

       Concur. However, if we do not use the US EPA Acute and Chronic Water Quality
       Criteria for surface waters (or the States' standards) what does STAC recommend?
       Updating existing criteria and developing criteria for additional chemicals and media (i.e.,
       sediment) is a long standing issue.  We cannot expect to improve our characterization
       unless our interpretative tools improve.  We will address this issue as part of the Toxics
       Reevaluation and Revision with STAC and the broader scientific community and other
       stakeholders in our Toxics Revaluation and Revision "science forum" that will be held in
       September.

Bullet 6:      "—(1) highlight fish tissue data and associated health advisories in future reports,
              (2) in conjunction with  state organizations, conduct a Bay-wide assessment of
              contaminants in edible species... and (3) reassess characterization of the mainstem
              ofBay..."

       Concur with all 3 items listed.  However, each and every endpoint must be matched to a
       regulatory decision framework or decision endpoint to  ensure that something will be done
       if a problem is discovered.  We will need to rely on the States and EPA to declare human
       health advisories from fish consumption to use in future characterizations.  It is important
       to note that this characterization is not a human health assessment. Where human health
       concerns already have been identified by the states, appropriate fish consumption
       advisories or other warnings have been issued. Please note: The Toxics Characterization
       did not assess the mainsteitLas  free of toxic impacts.  The mainstem was not characterized
       due to historically low levels of chemical contaminants. We are considering formally
       characterizing the mainstem of the Bay in subsequent updates.

4.  Textual Comments
Overview Comments/Questions
Bullet 1:
'...the distinction between 'exposure' and 'effects' is unclear."
       We will clarify the distinction between "exposure" and "effects" in the report. We
       will replace "exposure" with "concentration" when describing the data that was
       used in the characterization and will provide the definition stated below. We will
       continue to use the word "effects" for the reason stated below.  "Concentration" data
       refer to a method-defined value derived from a measurement by an instrument or other
       direct observations. It does not necessarily express the bioavailable form of the
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       contaminant measured and the pathway by which the contaminant has an effect on an
       individual organism, population, or community. "Effects" covers all potential and actual
       impacts to living resources as opposed to "toxicity" which suggests that we can attribute
       the impairment to a substance, eliminating all other potential and real causes.

Bullet 2:      "How will PCBs be quantified? ... Why was the Workgroup's confidence in using
              a total PCS threshold fairly low?"

       The Workgroup's confidence in using a total PCB benchmark was fairly low because the
       confidence of the authors who developed the total PCB benchmark was low (Long et ah,
       1995). The process for how PCB levels in sediment and fish tissue were evaluated is
       described in the Decision Rules (Technical Workplan, Appendix B, pages B-6 and B-9).
       Because the confidence of this approach was fairly low, PCB data were used to support a
       characterization and did not drive a characterization unless they were the cause of an
       existing fish consumption advisory. The reviewers mention that the sum of the
       congeners "will likely be a factor of 2 too low" but did not provide a reference for us to
       review so we cannot respond directly to that statement.

Bullet 3:      "...is dredged material analyzed in relationship to any toxics endpoints?"

       Data for or from site-specific problems or biased study areas (e.g., dredge material
       assessments, investigations at "hot spots") were not evaluated since we were attempting
       to characterize large areas (segments). Information or data concerning dredge material
       was not used since the material was probably targeted for removal and the problems, if
       any, may be resolved or will be resolved in the near future at the test site (don't know
       what will happen at the location where contaminated sediments will be placed). Also, we
       choose to use the most relevant and important management and characterization
       endpoints that we could find and that had some level of quality control and had passed
       some form of quality assurance.  The workgroup felt that relevant endpoints were
       important since neither management or the public will listen to any description of a
       problem unless it is relevant  and important to their respective interests.

Page-Specific Comments/Questions
Bullet 1:

       It is important to note that the verbiage used in the technical workplan and the public
       report regarding actions that  the Bay Program will take in the four different areas comes
       directly from the 1994 Chesapeake Bay Basinwide Toxics Reduction and Prevention
       Strategy. By classifying a segment as an Area of Emphasis we have determined by
       weighing the evidence and applying best professional judgement that there is sufficient
       data to say there is a problem and that actions are necessary now.  The Bay Program can
       use this characterization to act now to target  voluntary actions in these areas. Further
       studies may be necessary to better elucidate the problem and its sources before regulatory
       actions such as developing TMDLs are implemented by the States/District.

       As mentioned in section 1 of this response, we have added the following paragraph

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       to both the public report and technical workplan to explain the limited utility of the
       characterization for guiding management actions:  "The primary value and utility of
       the characterization is in identifying areas that need additional monitoring and assessment
       to better characterize the status of toxic effects on living resources inhabiting those areas.
       This characterization can also serve as a planning tool to help the Chesapeake Bay
       Program determine the areas in which to focus its voluntary pollution prevention and
       reduction efforts and the areas in which to focus its voluntary preservation/conservation
       efforts.  The characterization gives the State/District partners base information to allow
       them to conduct the more detailed risk assessment analysis, site specific analysis, and
       source assessment studies which may be necessary before regulatory actions can be
       taken."
Bullet 2:
       The statement is based upon our lack of knowledge of the potential for low levels of
       contaminants in the mainstem to have subtle yet important impacts on living resources
       throughout the Bay and tributaries. Our current arsenal of toxicity assessment tests do
       not allow us to adequately assess the impacts of the low levels of contaminants on living
       resources. Endocrine disrupters alone at extremely low concentrations have the potential
       for affecting population dynamics and community assemblages in the plankton found in
       the mainstem.
Bullet 3:

       The Regional Focus Workgroup did not develop set rules for defining how much data is
       enough to make a characterization because the size and attributes of each segment and the
       available data for each segment varied a great deal.  Adequate spatial coverage was an
       issue that was resolved by visually integrating the distribution of stations within a
       segment, the complexity of the watershed, and amount of data for each media type (water,
       sediment, and tissue) and contaminant class (metals, organic compounds). The
       determination of adequate coverage was treated in a weight of evidence fashion by each
       member of the workgroup and decided by best professional judgement. Reading through
       the segment profiles and the supporting data is a good way to get a feel for how much
       data was enough to make a characterization, when data were insufficient, and when data
       were inconclusive.

Bullet 4:

       It is unclear why the review panel thinks these terms are vague.  A good way to illustrate
       the difference between "strong evidence for a linkage" and "limited or no evidence for a
       relationship" is to compare data from a Region of Concern with an Area of Emphasis.
Bullet 5:

       See explanation in Bullet 1.
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Bullet 6:
       The reference provided for this statement in the public report is the 1999 Chesapeake Bay
       Basinwide Toxics Loading and Release Inventory which summarizes a preliminary mass
       balance conducted by Dr. David Velinsky, ANS, and Dr. Joel Baker, UMD-CBL.
Bullet 7:
       We are describing the data we used and not the thresholds. Thresholds are referenced in
       Appendix B of the Technical Workplan.

Bullet 8:

       Table 2 refers to the dates for which the Chesapeake Bay Program has data stored in its
       toxics database. Only a subset of these data were evaluated for the toxics characterization
       as described in Table 3. We clarified this in the Technical Workplan (Sections III.A.3
       and III.B.3.1) with the following text: "Of particular concern is the issue of methods for
       the measurement of metals in water. Older data did not use the "clean techniques" for
       measuring metals. It is believed that historical studies report metals that are bound and
       freely dissociated in the water column, while it is known that the more toxic form of a
       metal is the freely dissociated ion. The historical data were used with caution by the
       workgroup and were customarily used to confirm suggestions of concentrations in other
       media (sediments or tissue) that metals were a problem in a segment."

Bullet 9:

       Agree. We replaced the term "exposure" with "chemical contaminant concentration".

Bullet 10:

       We will include the following definition of "adequate spatial coverage":  "Adequate
       spatial coverage was an issue that was resolved by visually integrating the distribution of
       stations within a segment, the complexity of the watershed, and amount of data for each
       media type (water, sediment, and tissue) and contaminant class (metals, organic
       compounds). The determination of adequate coverage was treated in a weight of
       evidence fashion by each member of the workgroup and decided by best professional
      judgement."

Bullet 11:

       You are correct that additional data are available for the Virginia waters that,
       unfortunately, were not considered in the characterization.  The 1996 and 1997 benthic
       data from random sites in Virginia waters were not provided to the workgroup for use in
       the initial characterization. We will ensure that we acquire these data and evaluate
       them in future updates to the characterization.
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Bullet 12:
       To clarify this sentence we added the following text: "(e.g., lack of pesticide data in
       highly agricultural areas would tend to drive a classification towards an Area -with
       Insufficient or Inconclusive Data.)"
Bullet 13:
       Appendix B provides the complete set of decision rules and outlines the thresholds used
       and how they were interpreted. By listing the thresholds in a summary paragraph in the
       workplan as suggested, we run the risk of the reader assuming that we took these
       thresholds at face value. Therefore, we continued to list them only in the decision
       rules in Appendix B. It is important to note that although our characterization approach
       will stay more or less the same, it is likely that we will update the list of thresholds in
       future characterizations as our interpretative tools improve.
Bullet 14:

       We edited the text in section B.I. to be consistent with the correct text in the decision
       rules in Appendix B.

Bullet 15:

       See Bullet 11 for response.

Additional Actions:

       We have included a copy of the STAC review and the Toxics Subcommittee
       response as  an Appendix to the characterization report.
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