Targeting Toxics: A Characterization Report
A Tool for Directing Management and Monitoring Actions
in the Chesapeake Bay's Tidal Rivers
A Technical Workplan
June 1999
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 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
David Bailey Dr. Beth McGee
Potomac Electric Power Company (PEPCO) U.S. Fish & Wildlife Service
Kelly Eisenman Mark Richards
U.S. EPA Chesapeake Bay Program Office Virginia Department of Environmental Quality
Lenwood Hall Jim Stine
University of Maryland Baltimore Gas & Electric
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 characterization are Dr. Steve Brown, Maryland Department of Natural
Resources; Dr. Ian Hartwell, Maryland Department of Natural Resources; Deirdre Murphy,
Maryland Department of the Environment; Dr. Harriette Phelps, University of the District of
Columbia; and Dr. Fred Pinkney, U.S. Fish and Wildlife Service.
The Chesapeake Bay Program Office (CBPO) Characterization Team also deserves
recognition for loading and acquiring 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.
We recognize the Toxics Subcommittee, Regional Focus Workgroup, Jim Keating, EPA,
and Richard Batiuk, EPA CBPO, for technical review of this workplan and the Scientific and
Technical Advisory Committee for technical review of the 1995 protocol, on which this
workplan is based.
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TABLE OF CONTENTS
List of Tables and Figures iii
Abstract iv
I. Introduction 1
II. Overview 2
III. Conducting the Characterization 6
III.A. Identify, Acquire, and Compile Data
Types of Data Used in Characterization 6
Data Acquisition Efforts 7
Data Used in Characterization 8
Data Quality 10
Limitations of Data 11
III.B. Analyze and Interpret Data
Guidelines for Interpreting Data 12
Decision Rules for Interpreting Data 14
Data Analysis Issues 14
Data Analysis and Interpretation Displays 16
Factors Considered in Interpreting Data 17
Limitations in Data Interpretation 17
III.C. Characterize all Tidal Rivers of Chesapeake Bay
Guidelines for Characterizing a Segment 18
Making a Characterization 21
Insights into Making a Characterization 21
IV. Review of Characterization 22
V. Implications of Characterization 23
VI. Updates to Characterization and Recommendations 24
References 27
Tables and Figures
Appendix A: References of data in the Chesapeake Bay Toxics Database
Appendix B: Characterization Decision Rules
Appendix C: Characterization Thresholds Used based on Decision Rules
Appendix D: Scientific and Technical Advisory Committee Review of Characterization
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LIST OF TABLES AND FIGURES
Tables
Table 1.
Table 2:
TableS:
Table 4:
Figures
Figure 1:
Figures 2:
Figure 3:
Figure 4:
Figure 5:
Figure 6:
Figure 7:
Examples of Relevant Chemical Contaminant Data to consider in
Characterization.
Chemical Contaminant Concentration Data in the Chesapeake Bay Toxics
Database
Chemical Contaminant Concentration Data in the Chesapeake Bay Toxics
Database used in Characterization
Guidelines for Interpreting Chemical Contaminant Data and Making
Characterizations
Chesapeake Bay Tidal Tributary Segments Characterized for the 1999 Toxics
Characterization
Water Chemical Concentration Sampling Stations 1994-1998, Data Used in 1999
Toxics Characterization
Sediment Chemical Concentration Sampling Stations 1984-1998, Data Used in
1999 Toxics Characterization
Shellfish/Finfish Tissue Chemical Concentration Sampling Stations 1990-1997,
Data Used in 1999 Toxics Characterization
Chesapeake Bay Ambient Toxicity Assessment Program, Water/Sediment
Sampling Stations 1990-1996
Chesapeake Bay Benthic Sampling Locations (Fixed/Random) 1994-1997
Lower Potomac (LE-2) Random and Fixed Benthic Sampling Locations with
Levels of Dissolved Oxygen for 1994
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ABSTRACT
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, the status of chemical
contaminant effects on living resources inhabiting the Bay's tidal rivers. The result of that effort
is summarized in a public report: Targeting Toxics: A Characterization Report - A Tool for
Directing Management & Monitoring Actions in the Chesapeake Bay's Tidal Rivers [1]. This
report includes an executive summary, the characterization map, and profiles summarizing the
characterization for each river. This technical workplan is a companion document to the
characterization report and presents the technical approach used by the Chesapeake Bay
Program's Toxics Subcommittee Regional Focus Workgroup (hereafter, the workgroup) to
characterize the Bay's tidal rivers. This document serves as an update and expansion to the
earlier geographical targeting protocol published in 1995 [2]. This report details the chemical
contaminant and biological data used in the characterization, how the workgroup analyzed the
data, the thresholds used to interpret the data, and how the workgroup made final decisions. It
also addresses limitations to the characterization and recommendations for improving
characterizations in the future.
This characterization 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. It
goes beyond the state's impaired waters lists by identifying the areas where living resources may
be affected by chemical contamination (Areas of Emphasis), the areas that do not have any
known contamination problems (Areas with Low Probability for Adverse Effects) and the 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.
At the same time the characterization was being conducted, 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) [3]. The information in the characterization and TLRI reports will serve as valuable
planning tools to assist the Bay Program in assessing the success of its previous toxics reduction
and prevention goals and to formulate new goals for targeting additional chemical contaminant
management and monitoring efforts in specific tidal rivers.
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I. INTRODUCTION
Background
In 1992-1993 the Chesapeake Bay Program reevaluated the 1989 Chesapeake Bay
Basinwide Toxics Reduction Strategy to better understand and document the nature, extent, and
magnitude of chemical contamination and toxic effects within the Chesapeake Bay. The
resultant findings, described in the Chesapeake Bay Basinwide Toxics Reduction Strategy
Reevaluation Report, revealed that the magnitude and extent of chemical contaminant-related
problems in the Bay varied according to geographical region [4]. Findings showed that
significant chemical contaminant-related problems do not appear to be baywide, but are localized
in areas located near urban centers. The reevaluation process also indicated there are widespread
areas with low levels of chemical contaminants below thresholds associated with predictable
adverse effects on the Bay's living resources.
At its September 1993 meeting, based on the findings from the reevaluation, the
Chesapeake Executive Council designated three Regions of Concern where notable chemical
contaminant problems have been well documented by Bay scientists and managers: the
Anacostia River (DC), Baltimore Harbor/Patapsco River (MD), and the Elizabeth River (VA)
[5]. Currently, the jurisdictions are implementing Regional Action Plans, developed through the
Bay Program, in these areas to address the chemical contaminant problems. The Executive
Council also directed the Chesapeake Bay Program to revise the existing toxics strategy to
include a geographical targeting approach for reducing and preventing chemical contamination in
the Bay and rivers and for assessing chemical contaminant-related problems. Specifically they
directed the signatories to "direct reduction and prevention actions toward regional areas with
known toxics problems as well as areas where significant potential exists for toxic impacts on
living resources and habitats" and to "establish a process for characterizing and designating
additional areas of the Bay as Regions of Concern" [5].
The resulting revised Chesapeake Bay Basinwide Toxics Reduction and Prevention
Strategy, signed by the Executive Council in October 1994, commits the signatories to:
"By July 1996, evaluate available data through the 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" [6].
This report describes technical workplan followed to report on the status of chemical
contaminant effects on the living resources inhabiting the Bay's tidal rivers. This
characterization effort was much more intensive than originally anticipated, requiring five years
to complete. Similar geographical targeting efforts have been successfully applied on a regional
level in the Great Lakes and Puget Sound [7,8,9] and nationally through the Environmental
Protection Agency's National Sediment Quality Survey [10]. The background work from these
programs and the experience gained through their implementation provided a firm basis for
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establishing a geographical targeting component within the 1994 Chesapeake Bay Basinwide
Toxics Reduction and Prevention Strategy.
Regional Focus Workgroup
In 1994, the Toxics Subcommittee established the Regional Focus Workgroup to
implement the regional focus-related commitments in the 1994 basinwide toxics strategy. This
workgroup was charged with developing the geographical targeting protocol and conducting the
characterization. This five-year effort could not have been accomplished without the
commitment of the Regional Focus Workgroup's and the CBPO Characterization Team and their
perseverance.
In 1995, the workgroup developed the Chesapeake Bay Chemical Contaminant
Geographical Targeting Protocol which outlined the general approach for conducting the
characterization, including definitions of the classification categories and guidelines for making
the characterizations [2]. This protocol was reviewed and approved by the Toxics Subcommittee
and the Scientific and Technical Advisory Committee. In 1995 and 1996, the Bay Program held
a series of meetings throughout the watershed with key Bay scientists, managers, and citizens to
identify all available chemical contaminant and biological data. From 1996-1999, the workgroup
continued its extensive data acquisition by identifying additional data sets, acquiring all relevant
data, and loading data into a database for use in the characterization. In 1997, they refined the
geographical targeting protocol to include decision rules for evaluating the data. These decision
rules listed the thresholds and benchmarks to which different types of chemical contaminant
concentration and effects data were compared. By 1997, the membership of the workgroup was
composed of a consistent and well-balanced representation for conducting the characterization.
Workgroup members included representatives from state agencies (Virginia Department of
Environmental Quality, Maryland Department of the Environment, Maryland Department of
Natural Resources); federal agencies (US Fish and Wildlife Service, US Environmental
Protection Agency); interstate agencies (Interstate Commission on the Potomac River Basin);
research institutions (Old Dominion University, University of Maryland); and industries
(Baltimore Gas & Electric, Potomac Electric Power Company). From the summer 1998 through
April 1999, the workgroup engaged in the labor intensive process of using this workplan and
their best professional judgement to reach consensus on the characterization of all tidal rivers of
the Bay.
II. OVERVIEW OF CHARACTERIZATION
Purpose of the Characterization
The characterization represents the Chesapeake Bay Program's first comprehensive
analysis of available chemical and biological data to assess the status of chemical contaminant
effects on the living resources in the Bay's tidal rivers. This characterization goes beyond the
previously designated Regions of Concern, to characterize conditions in other tidal waters. The
characterization identifies areas where significant potential exists for chemical contaminant-
related effects on living resources and their habitats, areas that show evidence that adverse effects
due to chemical contamination are unlikely, and areas where data are lacking or inconclusive and
additional study is required. Based on available chemical and biological data, the Regional
Focus Workgroup characterized segments of the rivers into one of four categories:
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Regions of Concern (hot spots)
Areas of Emphasis
(significant potential for chemical contaminant problems)
Areas with Low Probability for Adverse Effects
(no known chemical contaminant problems)
Areas with Insufficient or Inconclusive Data
(data is too sparse or inconclusive to characterize conditions)
Overall, the characterization report and the 1999 Chesapeake Bay Basinwide Toxics
Loading and Release Inventory 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 effects.
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.
The Chesapeake Executive Council has directed the Bay Program to reevaluate and revise its
1994 basinwide toxics strategy in 1999. This characterization report and the TLRI report are
critical tools that will be used in developing future goals to direct chemical contaminant
reduction, prevention, and monitoring activities in the appropriate areas beyond the year 2000.
Types of Data Used for Characterization
Two types of data were considered in the characterization: chemical contaminant
concentration data and effects data. Concentration data available for this characterization were
chemical contaminant concentrations in water, sediment, and non-migratory, resident fmfish
tissue and shellfish tissue and information on any current fish consumption advisories. Effects
data available for the characterization were sediment and water ambient toxicity data and benthic
community structure data (See Section III. A. for more detail).
Human Health
The characterization identifies areas where chemical contaminant effects to the Bay's
living resources occur or have the potential to occur. Human health effects from contaminated
air, soil and drinking water are not addressed. However, because potential human health effects
are an important issue, state agencies have already looked at human health issues in the tidal
rivers of the Bay. And, where human health concerns already have been identified, appropriate
fish consumption advisories or other warnings have been issued. The characterization 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.
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Geographic Focus of Characterization
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 chemical contaminant problems are in tidal waters, and most of the urban
areas and contaminant-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.
Since the Chesapeake Executive Council previously designated the Anacostia River,
Baltimore Harbor/Patapsco River, and the Elizabeth River as Regions of Concern they were not
characterized as part of this effort. The workgroup evaluated the data from these regions and
verified that these data would have resulted in characterizing the areas as Regions of Concern,
based on the characterization process. Data from the Regions of Concern were used to provide a
context for selecting appropriate thresholds for potential or probable effects due to the presence
of contaminants and for evaluating the relative severity of contamination in other areas.
Spatial Scale of Characterization
The Chesapeake Bay Program divided the Bay and its tidal rivers into a number of
geographic segments based on salinity and other natural features for collecting, analyzing, and
reporting data. The Regional Focus Workgroup used this monitoring segmentation scheme to
characterize 38 tidal water segments (Figure 1). Most of the major 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 the spatial scale of these segments given the spatial and temporal
limitations of the available data. Also, this scale is appropriate for stakeholder groups who are
often organized around a river or watershed.
This effort represents 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 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.
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Characterization Categories
The Regional Focus Workgroup evaluated all relevant, available chemical contaminant
and biological data for all tidal river segments of the Chesapeake Bay and characterized them in
one of the four categories:
Region of Concern - Available data indicate that there is a probable chemical contaminant-
related problem. Data denote elevated concentrations of chemical contaminants above thresholds
associated with adverse effects and observed toxic effects on living resources. In this case, data
reveal strong evidence for a linkage between the presence of chemical levels exceeding
thresholds and the observed effects on living resources in this region. Regions of Concern are
formally designated by the Chesapeake Executive Council and targeted for specific chemical
contaminant remediation, reduction, and/or prevention actions through jurisdictional
development and implementation of Regional Action Plans.
Area of Emphasis - Available data indicate that there is significant potential for a chemical
contaminant-related problem. In this case, 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. For these regions, the appropriate
jurisdiction(s) will initiate the necessary actions to effectively manage the area. Pollution
prevention actions will be targeted towards specific chemical contaminants and sources with the
goal of eliminating the potential for chemical contaminated-related effects.
Area with Low Probability for Adverse Effects - Available data indicate that it is unlikely that
there is a chemical contaminant-related problem. In this case, data reveal measured chemical
contaminant concentrations below thresholds associated with adverse effects and/or no reported
or measured chemical contaminant-related adverse effects on living resources. For these regions,
the appropriate jurisdiction(s) will take actions necessary to ensure future protection.
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 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.
Relationship to 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 Actio develop a
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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 effects 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
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.
III. CONDUCTING THE CHARACTERIZATION
This section details the following three steps the Regional Focus Workgroup took to
conduct the characterization:
1. Identify, acquire, and compile all relevant, available chemical contaminant and biological
data.
2. Analyze and interpret chemical contaminant and biological data.
3. Characterize all tidal rivers into one of the four categories.
A. STEP I: IDENTIFY, ACQUIRE, AND COMPILE ALL RELEVANT,
AVAILABLE CHEMICAL CONTAMINANT DATA.
A.I. Types of Data Used in Characterization
The first step in implementing the geographical targeting protocol was to identify and
acquire all available ambient chemical contaminant data and other relevant information for all
tidal rivers of the Chesapeake Bay. A variety of different types of data is needed to build the
weight of evidence necessary in making a characterization. Examples of relevant information the
workgroup considered as evidence for the presence/absence of a chemical contaminant-related
problem are listed in Table 1.
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Chemical Contaminant Concentration Data
"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 contaminant measured and the pathway by which the contaminant has an effect on an
individual organism, population, or community. 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. Data available for this
characterization were chemical contaminant concentration data for water, sediment, and non-
migratory, resident finfish tissue and shellfish tissue and information on any current fish
consumption advisories.
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.
Spatial coverage of effects data was very limited compared to the chemical contaminant
concentration data. Effects data available for the characterization were sediment and water
ambient toxicity data and benthic community structure data. Data on finfish and shellfish
abnormalities were not used due to the difficulty of linking the observed abnormalities to
chemical contamination.
Table 1. Chemical Contaminant Data Considered in the Characterization.
CONCENTRA TION DA TA EFFECTS DA TA
\ Water column contaminant concentrations ! Water column toxicity
! Sediment contaminant concentrations ! Sediment toxicity
! Edible non-migratory, resident finfish tissue ! Impaired benthic community structure
contaminant concentrations
! Shellfish tissue contaminant concentrations
! Fish consumption advisories
A.2. Data Acquisition Efforts
Due to the relatively high costs of chemical contaminant assessments, the Chesapeake
Bay Program relies heavily on data collected by its partner federal agencies (NOAA, USGS,
EPA), state agencies, and research institutions in addition to the Toxics Subcommittee-funded
projects such as the Ambient Toxicity Assessment and Fall Line Monitoring programs to use in
targeting its chemical contaminant management and monitoring activities.
In 1995, when the Regional Focus Workgroup undertook the characterization endeavor,
the Chesapeake Bay Toxics Database was comprised mainly of baywide chemical contaminant
concentration data for water, sediment, and finfish/shellfish tissue. In order to characterize toxic
conditions in specific segments of the tidal rivers, the Bay Program turned its data acquisition
focus towards more regional datasets. In 1995 and 1996 the Bay Program held a series of
meetings throughout the watershed with key scientists, managers, and citizens to identify datasets
that would help them to characterize chemical contaminant conditions in the tidal rivers. They
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prioritized the datasets for acquisition and sent out letters requesting the data with specifications
for data submission. The Bay Program developed a database to track all identified datasets and
its progress in acquiring and loading them into the Chesapeake Bay Toxics Database.
The Bay Program's goal is to make a full range of Bay related data and information
directly accessible via the internet in consistent as possible formats. The Chesapeake Bay Toxics
Database is a first step towards a more distributed system. In the absence of a comprehensive
baywide chemical contaminant monitoring program, the Bay Program is compiling many smaller
datasets scattered across many data generators and putting them into a consistent format so that
they can be analyzed efficiently. In the future, the Bay Program will move towards a more
distributed database where data are maintained in a consistent format by the data generators and
shared with the Bay Program via the internet..
A.3. Data Used in the Characterization
The Chesapeake Bay Toxics Database contains the water, sediment, fmfish/shellfish
tissue chemical contaminant concentration data and the appropriate thresholds to which these
chemical contaminant concentration data are compared. Summaries of the effects data, including
benthic community structure and most of the ambient toxicity data are stored in spread sheets
that are linked to software that geographically displays these data. When necessary, hardcopies
of other relevant effects data were evaluated as well. The preponderance of data used in this
initial characterization are chemical contaminant concentration data, with effects data from a
limited portion of the tidal waters.
Chemical Contaminant Concentration Data
Table 2 summarizes all concentration data in the Chesapeake Bay Toxics Database as of
March 31, 1999 for the tidal waters of the Bay. These data date back as far as 1976 and include
measurements in the mainstem Bay which was not characterized. The references for all studies
in the database are attached [Appendix A]. Table 3 summarizes the subset of relevant data for
the tidal rivers considered in the 1999 characterization. In support of the characterization, a total
of 53 chemical contaminant concentration datasets were used for water, sediment, and
fmfish/shellfish tissue, comprised of 124,087 observations (including below detection limit
values) collected at 1,062 sampling stations throughout the tidal rivers.
The workgroup evaluated all available data for each segment and made a decision on the
date range they should consider for making characterizations. Sometimes the workgroup chose
to evaluate older data to assess persistence of a chemical contamination over time, particularly
for sediment contaminant data. 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 and therefore were used with caution by the workgroup and were customarily used only to
confirm suggestions of concentrations in other media (sediments or tissue) that metals were a
problem in a segment. The workgroup considered sediment data from the early to mid-1990's to
be representative of current conditions in the absence of any dredging, catastrophic freshets that
move sediment, or remediation activities. The workgroup would not use these data as
representative of current conditions if they had information that indicated that the sediment
contaminant levels had changed. An example of this type of information would be if the area
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was a high depositional area, or management actions were implemented since the data were
collected that may have resulted in clean sediments entering the system. Greater weight was
given to recent data that were considered more representative of the current conditions in the
segment. For all segments combined, sediment data from 1984 - 1998, fish tissue data from
1990-1997, and water data from 1994-1998 were evaluated for the characterization.
Table 2: Chemical Contaminant Concentration Data in the Chesapeake Bay Toxics
Database (as of 3/31/1999)
Medium
Sediment
Tissue
Water
# datasets
30
13
23
# observations
(% total obs.)
151,943(49%)
81,385 (27%)
73,570 (24%)
# monitoring
segments
46
41
36
date range
1976-1997
1976-1998
1976-1998
# (%) of
sampling
stations
1,455 (54%)
770 (28%)
495 (18%)
Table 3: Chemical Contaminant Concentration Data in the Chesapeake Bay Toxics
Database used in Toxics Characterization (as of 3/31/99)
Medium
Sediment
Tissue
Water
# studies
27
7
19
# observations
% total obs.
66,423 (53%)
4,378 ( 4%)
53,286 (43%)
# monitoring
segments
36
13
29
date range
1984-1998*
1990- 1997*
1994-1998*
# (%) of
sampling
stations
644 (61%)
46 ( 4%)
372 (35%)
* Note: date ranges for data used in the Toxics Characterization were specific to each segment characterized.
These ranges represent the earliest and latest dates of data used in any of the 36 segments.
Figures 2-4 illustrate the data density and spatial coverage of the chemical contaminant
concentration data used from a variety of different studies. Although water contaminant
concentration data comprised approximately 43% of all concentration data considered for the
characterization, the spatial coverage of recent water contaminant data was limited in many
segments (Figure 2). There was adequate spatial and temporal coverage in most segments for
sediment chemical contaminant concentration data and these data comprised approximately 53%
of all concentration data considered for the characterization (Figure 3). Recent tissue chemical
contaminant concentration data were extremely limited both spatially and temporally (Figure 4).
Although there was good spatial coverage of finfish/shellfish tissue contaminant concentration
data in the mid 1980's, these data could not be used to represent a current characterization of the
tidal rivers. The Bay Program is working with the state monitoring programs to get access to
additional fish tissue and water contaminant concentration data for future updates to the
characterization. Adequate spatial coverage was an issue that was resolved by visually
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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.
Effects Data
The Chesapeake Bay Ambient Toxicity Assessment Program provides water and
sediment ambient toxicity data and concurrent water and sediment contaminant concentration
data for 46 stations in 16 rivers (Figure 5, [11]). Benthic community data were relatively
plentiful, especially in Maryland waters (Figure 6). The random benthic sampling data for
Virginia waters from 1996 and 1997 were not available at the time of this characterization but
will be evaluated in future characterizations. No finfish/shellfish abnormality data were used in
this characterization due to the difficulty in ruling out causes of abnormalities other than
chemical contamination.
A.4. Data Quality
There were several points throughout the data acquisition, loading, and evaluation
process where the quality of the data was assessed. If data were from studies funded directly by
the Chesapeake Bay Program, the Bay Program quality assurance/quality control officer reviewed
the quality assurance/quality control project plan to ensure that the study design and data
collection and analysis techniques were sound. The Bay Program's Toxics Subcommittee and
workgroups reviewed all project deliverables to ensure that they were of good technical quality.
If data were from studies not funded by the Bay Program, the Bay Program requested the
appropriate documentation on data quality. The Workgroup carefully evaluated all data in
making its characterizations, including age of data, detection limits, analytical methods, use of
ultra-clean techniques for metals analysis, and adequacy of reference sites. Through careful
analysis of the data, they were able to detect data inconsistencies that may indicate quality
problems and eliminate questionable datasets from the analysis.
The loading of the data into the Chesapeake Bay Toxics Database was a multi-stepped
process. Upon receiving new data for inclusion in the Toxics database, Bay Program Data Center
toxics database managers reviewed the submitted data to ensure that it met quality control
criteria. At a minimum, data needed to have the following clearly identified: sampling agency;
sampling locations and their associated latitudes and longitudes; parameters sampled; dates of
sampling; medium sampled (i.e., sediment); sampling units; and an explanation of associated
qualifiers. Additionally, if the values were reported as not detected, detection limits were
required. Information that enhanced the utility of the data, but was not required for inclusion,
included: chemical species; analytical instrumentation; method detection limit; and analytical
methodology. After performing an initial review of the data, the database managers referred all
problems or questions about the data to the agency or person that submitted the data for
resolution. Also, any information that would enhance the utility of the data, but was not captured
by the current structure of the Chesapeake Bay Toxics Database, was placed in a "comment"
field. Once outstanding issues were resolved, the database managers converted the data to the
Chesapeake Bay Toxics Database format. To ensure quality control, parameters and units were
standardized. Additionally, before new location values were assigned, the location table in the
Chesapeake Bay Toxics Database was queried to identify stations that would duplicate existing
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stations. Finally, prior to uploading the data, database managers ran a series of quality assurance
programs to identify any problems that may have occurred during the data conversion process
including duplication of data or unit conversion problems.
A.5. Limitations of Data
It is important to note that there is no baywide monitoring program designed to
characterize toxics conditions in the Chesapeake Bay tidal rivers on the scale necessary to
perform comparable assessment of all rivers. That is, although the Bay Program has supported
an ambient toxicity assessment program since 1990 (the studies usually focus on one or more
segments in two basins in any year), it is inadequate for characterizing all tidal rivers at the
current funding level. The workgroup was faced with the challenge of piecing together many
disparate datasets and developing a consistent set of decision rules for how to interpret this
information in making a characterization. Some of the limitations of the data are listed below.
This initial characterization is based on only those priority data that were available and
loaded into the Chesapeake Bay Toxics Database by March 31, 1999. Many more
datasets are still being acquired and loaded that will be captured in future updates of the
characterization.
Overall there was a general lack of water and fmfish/shellfish chemical contaminant
concentration data and effects data throughout the tidal rivers. Data was particularly
lacking in most of the Eastern Shore rivers. Very little pesticide data were available.
The preponderance of available data used in this initial characterization was chemical
contaminant concentration data. Sediment chemical contaminant concentration data
make up the majority of the concentration data used in the characterization and tend to
"drive" most of the characterizations.
Available water and fmfish/shellfish tissue contaminant concentration data for most
segments were too old to be representative of current conditions and, therefore, were of
limited use in making the characterizations. Even though many of the current fish
consumption advisories are based on these older data, if the states/District have an active
fish consumption advisory in place, then the Workgroup considered them in its
characterizations.
This characterization is limited to the chemicals for which we have available data.
Therefore, chemicals were not considered in the analysis if they were not routinely
analyzed for, such as new use pesticides or nonyl phenols, even though they may have a
high use, toxicity, or persistence. However, the workgroup considered the absence of
ambient chemical contaminant concentration measurements in areas where they would
expect to see these chemicals in making its characterizations (e.g., lack of pesticide data
in highly agricultural areas would tend to drive a classification towards an Area with
Insufficient or Inconclusive Data.)
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Studies differed in their objectives, sampling strategies, type of data collected, chemicals
measured, analytical methods used, locations and time sampled, etc. The utility of these
studies may be limited because they were not conducted with the purpose of
characterizing chemical contaminant conditions on the same spatial scale as this effort.
Many of the datasets are biased towards areas of known or suspected problems resulting
in limited data for areas that are thought to be uncontaminated. The workgroup focused
on studies that reported data on the ambient environment. The workgroup qualified all
studies that were conducted for the purpose of quantifying the chemical contaminant
levels or effects in close proximity to a source (i.e., point source discharge pipe) if they
decided to use them in the characterization. If no toxicity was observed in these studies
targeted to suspected toxics sources, these findings could be used as evidence for the
unlikelihood of a chemical contaminant effects on living resources.
Although benthic community data were relatively plentiful, especially in Maryland
waters, these data were of limited use, because of the difficulty in ruling out dissolved
oxygen and other non-contaminant-related factors as the principle cause of degradation
on the benthic community. For this reason, benthic and fish community data (when
available) were used as supporting evidence in making a characterization, but did not
drive a characterization.
No finfish/shellfish abnormality data were collected and used in this characterization due
to the difficulty in ruling out causes of abnormalities other than chemical contamination.
It is important to note that other environmental factors such as low dissolved oxygen and
pH may influence the health of living resources in the Bay by affecting the toxicity of
substances in the environment. Assessing impacts from "non-anthropogenic" substances
that are not chemical contaminants was beyond the workgroup's capacity to evaluate with
the available data. The workgroup did consider in situ effects measures where low
dissolved oxygen levels may have been a causative factor for reduced benthic indices
because the data were available.
B. STEP II. ANALYZE AND INTERPRET CHEMICAL CONTAMINANT
DATA
B.I. Guidelines for Interpreting Data
In order to characterize a segment into one of the four categories, the chemical
contaminant concentration and effects data were initially compared to contaminant thresholds or
control conditions, respectively. The thresholds were developed for each media (water,
sediment, tissue) and for each effect using the guidelines detailed below and summarized in
Table 4. The comparison provided a body of "evidence" for where (spatially), when
(temporally), how much (magnitude), and what (concentration or effects) chemical contaminant
levels and toxic effects may be occurring.
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Water Column Contaminant Concentration - Observed ambient water column chemical
contaminant concentrations were compared with relevant chemical contaminant concentrations
known to be protective of most aquatic organisms (i.e., EPA aquatic life criteria, respective state
water quality standards) or with other relevant thresholds above which adverse effects to aquatic
organisms have been observed and documented (i.e., laboratory-based chemical specific toxicity
tests) (Appendix B and C).
Bottom Sediment Contaminant Concentration - Observed ambient sediment contaminant
concentrations were compared with contaminant threshold concentrations associated with
adverse biological effects. Sediment quality threshold values were compiled from peer-reviewed
literature and technical reports, summarized in a sediment threshold compendium [12] and stored
on the Chesapeake Bay Program Toxics Database. The most appropriate (i.e., higher level of
certainty and most applicable to the Bay region estuarine organisms) threshold values were
selected for comparison to sediment contaminant data (Appendix B and C)..
Finftsh/Shellfish Tissue Contamination - Measurements of the edible portion of finfish tissue
contaminant concentrations in resident, non-migratory species and shellfish tissue contaminant
concentrations were compared with thresholds associated with the protection of human health.
Available human health consumption threshold values were compiled from national and
worldwide literature and government documents and summarized in a fish tissue threshold
compendium [13] and stored on the Chesapeake Bay Program Toxics Database. The most
appropriate (i.e., higher level of certainty) threshold values were selected for comparison to fish
tissue contamination data (Appendix B and C).. Existing chemical contaminant-related fish
consumption advisories and bans also were used as evidence in making a characterization.
Water Column/Bottom Sediment Toxicity - Observed ambient water column and bottom sediment
toxicity data from the Chesapeake Bay Ambient Toxicity Assessment Program have already been
interpreted by assigning a "degree of toxicity" to a sampled area [11]. These degrees of toxicity
were used in interpreting the data for this characterization. Workgroup members also evaluated
the sediment and water toxicity index values which provide a relative measure of toxicity of a
given site compared to all other sites sampled to date by this program. Toxicity data collected
through other programs were evaluated for statistically significant differences between the
observed adverse effects (i.e., survival, growth, reproduction) and reference area or control
toxicity test results (Appendix B).
Benthic Community Structure - Benthic community data (i.e., species number, species diversity,
and biomass) collected for the Bay Program were summarized into a Benthic Index of Biotic
Integrity (B-IBI) that indicates benthic community health [13,14, 16]. A B-IBI of greater than or
equal to 3 indicates the benthic community meets or exceeds the restoration goal (a benthic
community characteristic of a non-degraded bottom habitat in Chesapeake Bay); an index of 2.6
to 3 indicates a marginal benthic community; an index of 2 to 2.6 indicates a degraded benthic
community; and an index of 2 or less indicates a severely degraded benthic community. Only
data for regions where low dissolved oxygen conditions could be eliminated as the principle
cause of benthic community degradation were used as supportive evidence in making a
characterization (Appendix B).
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B.2. Decision Rules for Interpreting Data
Through many deliberations, the Regional Focus Workgroup reached consensus on a set
of decision rules to provide a uniform and unbiased method for screening chemical contaminant
concentration and effects data for each segment (Appendix B). The decision rules list multiple
sets of thresholds used to interpret chemical contaminant concentration data. The workgroup
chose multiple sets of thresholds for each data type (i.e., water, sediment, fish tissue) because no
one set of thresholds covers all chemicals measured and because of the diversity of opinions in
the scientific community regarding the confidence and utility of each threshold. The workgroup
ranked the thresholds appropriate for each data type based upon the level of confidence in the
ability of the threshold to predict effects or protect living resources and on the scientific validity
of the approach used to develop the threshold. Appendix C provides a complete listing of the
contaminant-specific thresholds used. The decision rules also include uniform methods for
interpreting the effects data (benthic community assessments and ambient toxicity test data).
Concentration: Threshold Ratio
The concentration:threshold ratio is the ratio of the measured chemical contaminant
concentration in an environmental sample (water, sediment, tissue) divided by a relevant
threshold. If the ratio is less than 1.0, it suggests that the condition predicted by the threshold
(mortality, reduced growth or reproduction, bioaccumulation, etc.) may not be occurring. If the
ratio is greater than 1.0, the threshold has been exceed, suggesting that some level of effect may
be occurring. For ratios much greater than 1.0, there is an increasingly greater level of
confidence that an effect is occurring. This ratio was used by the workgroup to estimate the
confidence in predicting that an effect may be occurring, given the inherent uncertainty in the
thresholds and the environmental measurements. Greater weight was given to a ratio of 2.0 or
greater, but it was not considered an indicator of the magnitude of the effects. This is, higher
ratios do not necessarily indicate greater toxicity because toxicity is not always related to
concentration in a linear dose-response fashion.
B.3. Data Analysis Issues
B.3.1. Exposure Data
Below Detection Limit Values
In many cases, chemical contaminants that were measured using a specified detection
limit were not detected. Therefore the concentration of these chemicals falls somewhere between
zero and the detection limit. In the data analysis, these chemicals were referred to as "below
detection limit values" and were not assigned a specific chemical concentration. Data on
chemical measurements that were below the detection limit were used as evidence supporting
characterizing a segment as an Area with Low Probability for Adverse Effects. Sometimes the
detection limit for these chemicals was greater than the thresholds. In this case, it is possible that
the chemical value may exceed a threshold. If detection limits for a measured chemical were
greater than the thresholds used for comparison, these data were flagged in the analysis for the
workgroup's consideration.
Evaluating Contaminants that Exceed Thresholds
Some contaminants reported in the database are not considered toxic in estuarine
environments. The workgroup considered this in evaluating data for each segment, placing less
weight on metals (e.g., aluminum, manganese, and iron) that are typically non-toxic in estuarine
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settings. Also, the database contained some compounds that are present in laboratory plastics
(e.g., di-(2ethylhexl)phthalate), and these compounds were not considered in the evaluation.
Additionally, in determining its level of confidence in a chemical exceeding a threshold,
the Workgroup considered reviews in the scientific literature regarding thresholds and their
utility in predicting toxic effects. For example, NOAA ER-L/ER-M sediment threshold values
for nickel have not proven to be reliable predictors of sediment quality (Long et al., 1995); hence
the workgroup has less confidence in the exceedence of this threshold.
Consistency Issues between EPA Water Quality Criteria and State Standards
For some chemicals Maryland and Virginia used different water quality standards in
which to compare their ambient data. The workgroup decided to address this inconsistency on a
segment by segment basis if and when characterizations appeared to be driven by the use of a
threshold that was not consistently used by both jurisdictions in their individual characterization
efforts.
Metals Data
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.
Analysis of metals in sediment can be reported as either total or total recoverable,
depending on the extraction technique used in the laboratory, where the total value is greater than
the total recoverable value. Studies such as the EPA Environmental Monitoring and Assessment
Program (EMAP) report total metals, while state programs tend to report total recoverable. It is
most appropriate to compare total measurements with the NOAA ER-L and ER-M thresholds,
since they are based on total metals measurements. However, the workgroup also compared the
lower total recoverable values to the thresholds. If a total recoverable measurement exceeded the
threshold, the workgroup's confidence in that exceedence was high.
Polychlorinated Biphenyls (PCBs) in Sediment
Since there are few, if any, sediment thresholds for individual PCB congeners and
arochlors, the workgroup compared the sum of the PCB arochlors and the sum of the PCB
congeners to "total PCB thresholds" listed in Appendix B. Since the workgroup's confidence in
using a total PCB threshold was fairly low, results of this analysis were used only as supporting
evidence in making a characterization.
PCBs in Fish Tissue
Since there are few, if any, fish tissue thresholds for individual PCB congeners and
arochlors, the workgroup compared the sum of the PCB arochlors and the sum of the PCB
congeners to the "total PCB thresholds" listed in Appendix B. Since the workgroup's confidence
in using a total PCB threshold was fairly low, results of this analysis were used only as
supporting evidence in making a characterization.
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B.3.2 Effects Data
Evaluating Benthic Community Structure Data
Dissolved oxygen concentrations of 2 mg/L and below are known to have sublethal and
lethal effects on the benthic community. In some parts of the Bay and rivers during the spring
and summer months, bottom waters become hypoxic, falling below this 2 mg/L threshold
intermittently or persistently. In order to rule out dissolved oxygen as the causative factor for
degraded benthic communities, the workgroup worked with the Chesapeake Bay Program
Office's GIS and Monitoring team and the principal investigators of Maryland's Chesapeake Bay
benthic monitoring program at Versar to make a link between benthic community conditionas
expressed by its IBI score-and the degree of exposure of the community to dissolved oxygen
concentrations below 2 mg/L.
Although dissolved oxygen measurements are taken when the benthic community is
sampled, it represents only one point in time. Because dissolved oxygen concentrations at a
given site can vary greatly over a 24-hr period as well as over weeks and months, a single
measurement at or near the time the benthic community is sampled may not reflect the longer-
term exposure conditions of the community. A better characterization of dissolved oxygen
conditions at these sites can be derived from dissolved oxygen measurements collected at stations
in the vicinity (i.e., in same segment) as part of the Chesapeake Bay Program Water Quality
Monitoring Program. During the spring and summer months, dissolved oxygen samples have
been collected twice a month at most stations in the sampling network over the past 14 years.
A method was developed to estimate the depth at which benthic communities at a
particular location were exposed to a dissolved oxygen concentration of 2 mg/L or less a
significant amount of time (> 10 percent) [17]. The method uses an equation based on the 13
years of monitoring data and the relationship between average monthly or seasonal
concentrations and the percent of observations below the selected threshold concentration. The
relationships and, thus, the equations are specific to each Bay Program segment and include as
variables the specific factors of month (March through October) and depth (meters), in addition
to mean dissolved oxygen concentrations. The Chesapeake Bay Program's GIS team used the
Bay Program volumetric Mainstem and Tributary Interpolator and the depth values from the Bay
Program bathymetry database to map the region of bottom habitat showing the depth where
dissolved oxygen concentrations were 2 mg/L or less at least 10 percent of the time.
Figure 7 shows an example of the maps that the workgroup evaluated, showing the
benthic IBI scores and the low dissolved oxygen zones within a given segment. Degraded
benthic communities that are not in the low dissolved oxygen zone could be caused by other
factors such as chemical contamination. Chemical contamination may be a co-stressor for
degraded benthic communities in low dissolved oxygen zones, but the relative contributions of
these two potential stressors cannot be determined using available data.
B.4. Data Analysis and Interpretation Displays
Through programming the Chesapeake Bay Toxics Database, the Chesapeake Bay
Program Office Characterization Team developed data analysis and interpretation displays to aid
the workgroup in making its characterization. For every tidal river segment, each workgroup
member received a data packet with the following information:
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Map showing all sampling stations sampled for water, sediment, and finfish/shellfish
chemical contaminant concentration data; benthic community data; and ambient toxicity
data; and a full listing of all of the study references
Maps showing the level of contamination at each station for water, sediment, and
finfish/shellfish contaminant concentration data; ambient toxicity data; and benthic
community data based on the decision rules
Scatter plots showing years and levels of contamination for each chemical measured at
each sampling station to indicate magnitude and persistence of chemical contamination
problems
Hardcopy summaries of ambient toxicity test data to supplement maps
Maps showing benthic community data and dissolved oxygen levels to rule out low
dissolved oxygen as causative factor of degraded benthic communities.
Tables providing both raw and summarized data supporting the maps and scatter plots.
Table summarizing all references of all datasets used in the analyses
B.5. Factors Considered in Interpreting Data
The Regional Focus Workgroup members considered many different factors in reviewing
the available data for each segment. Typical questions they asked themselves as they evaluated
the data are the following:
What exposure and effects studies are available for this segment?
What is the quality of these data?
What is the spatial and temporal distribution of the data?
Was a comprehensive suite of chemicals that we might expect to find in this segment
analyzed?
Are thresholds available for most of the chemicals measured?
How often were thresholds exceeded?
How pervasive were these exceedences, spatially?
How often were chemical contaminant concentrations greater than twice the threshold?
(In other words, how confident was the workgroup in the exceedence?).
Are the chemicals that exceeded thresholds persistent over time?
Are the chemicals that exceeded thresholds considered to be bioaccumulative or toxic?
Is there similar evidence of contamination among media sampled (water, sediment, fish
tissue) or among stations?
Do the data indicate any toxic effects on living resources?
Is there a correlation between elevated chemical levels and toxic effects?
Is there evidence of a segment-wide chemical contaminant problem, or are problem areas
localized to one or a few stations?
The decision rules and data analysis displays provided a standardized output of information for
the workgroup to consider as they addressed these questions. Ultimately, the workgroup's
characterizations were based on the weight of evidence and their best professional judgement.
B.6. Limitations in Data Interpretation
The resulting characterization is only as good as the available data and the tools used to
interpret these data. Limitations in the data have already been discussed in Section II. Below are
some limitations in the interpretative tools:
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Not all chemicals measured have thresholds associated with them. In the absence of
thresholds, these data could not be used in the characterization.
Because there are no EPA-approved sediment criteria, sediment thresholds and
benchmarks used for interpreting sediment contaminant concentrations have a lower level
of confidence than water quality criteria. This is important to note since sediment data
drove most of the characterizations.
The Benthic Index of Biotic Integrity (B-IBI) is an index used by the Bay Program to
address management questions and set new restoration goals. However, interpretation of
the data have been largely limited to the known relationship between low dissolved
oxygen and degraded benthic communities. Without a way to interpret benthic data in
relation to chemical contamination, we are limited in our use of these data, particularly in
those areas where low dissolved oxygen cannot be ruled out as a cause for benthic
degradation.
The interpretation of the chemical contaminant data is based on thresholds. The extent to
which and how low level chemical contaminant exposure (including the potential for
additive and synergistic effects from multiple chemical contaminants) may pose a risk to
the Bay's living resources is largely unknown. Such information from the Chesapeake
Bay Environmental Effects Committee Toxics Research Program and other research
programs could improve the characterization and help the Bay Program better target
monitoring in the future.
Data are lacking for important assessment parameters such as total organic carbon (TOC),
acid volatile sulfides (AVS), and simultaneously extractable metals (SEM) that indicate
the bioavailability and subsequent toxicity of measured chemical contaminant levels.
AVS, SEM, and TOC measurements which are used for assessing sediment toxicity of
trace metals were only available for metals data collected concurrently with data collected
for the Chesapeake Bay Ambient Toxicity Assessment Program. A TOC content of 2%
was assumed in calculating those thresholds dependent on TOC levels since most TOC
levels in the Bay fall within a range of 1 - 4%. However, TOC can vary as much as 0.1-
10%.
C. STEP III: CHARACTERIZE ALL TIDAL RIVERS OF THE CHESAPEAKE
BAY
C.I. Guidelines for Characterizing a Segment
The final step in conducting the characterization was to evaluate the data for each
segment and make a characterization. The general characterization guidelines used by the
workgroup for characterizing a segment into one of the four categories are listed in Table 4 and
detailed below.
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Region of Concern
For a segment to be characterized as a Region of Concern, the following must be
documented:
(1) Multiple measurements of one or more chemical contaminants in the water, bottom
sediments, and/or finfish/shellfish tissue at concentrations exceeding the established
water column, sediment, or tissue thresholds, respectively;
AND
(2) Multiple observations of one or more adverse effects on living resources exposed to the
waters and/or sediments of that area;
AND
(3) Strong evidence for a causal relationship between the measured water column and/or
sediment chemical contaminant concentrations and the observed chemical contaminant-
related adverse effects on the Bay's living resources, where causes other than chemical
contamination (i.e., low dissolved oxygen conditions and disease) can be eliminated.
Area of Emphasis
For a segment to be characterized as an Area of Emphasis, the following must be
documented:
(1) Multiple measurements of chemical contaminants in the water column, bottom sediments,
and/or finfish/shellfish tissue at concentrations exceeding the established water column,
sediment, or tissue thresholds, respectively;
AND/OR
(2) Multiple observations of one or more adverse effects on living resources exposed to the
waters and/or sediments of that area;
In this case, there is limited or no evidence for a relationship between the measured water
column and/or sediment chemical contaminant concentrations and the observed chemical
contaminant-related adverse effects on the Bay's living resources, where causes other than
chemical contamination (i.e., low dissolved oxygen conditions and disease) can be eliminated. If
sufficient data are available for both exposure and effects data, then both conditions (1) and (2)
need to be met. If data are only available for exposure data, then only condition (1) needs to be
met to characterize an area into this category. If data are only available for effects data, then only
condition (2) needs to be met to characterize an area into this category.
There are several cases when a segment can be characterized into this category. If a
segment has limited or no effects data, but shows evidence for exposure data that exceed
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thresholds, it may be characterized as an Area of Emphasis. If a segment has limited or no
exposure data, but there are observations of adverse effects, it may be characterized as an Area of
Emphasis. A segment may also be characterized into this category when both effects data and
exposure data exceeding thresholds are observed, but there is no relationship between the two.
Area with Low Probability for Adverse Effects
For a segment to be designated as an Area with Low Probability for Adverse Effects, the
following must be documented:
(1) Multiple measurements of multiple chemical contaminants in the water column, bottom
sediments, and/or finfish/shellfish tissue at concentrations below the established water
column, sediment, or tissue thresholds, respectively;
AND/OR
(2) Multiple measurements of one or more chemical contaminant-related adverse effects on
living resources yield no evidence for adverse effects significantly different from controls
or reference areas.
In the original geographical targeting protocol [2], a segment could not be characterized
into this category unless both exposure and effects data provided enough evidence that there was
not a chemical contaminant-related problem. As the workgroup evaluated data, they quickly
realized that there are very few cases where sufficient exposure and effects data are available in a
segment. Good spatial coverage of effects data are limited in the tidal rivers. The workgroup
found that, in the absence of effects data, exposure data may be sufficient for assigning a segment
to this category. If sufficient data are available for both exposure and effects data, then both
conditions (1) and (2) need to be met to characterize an area into this category. If data are only
available for exposure data, then only condition (1) needs to be met to characterize an area into
this category. If data are only available for effects data, then only condition (2) needs to be met
to characterize an area into this category.
Area with Insufficient or Inconclusive Data
For an area to be designated as an Area with Insufficient or Inconclusive Data., the
following must be documented:
(1) Either the measurements of chemical contaminants in water, sediment, or finfish/shellfish
tissue are too limited temporally and/or spatially, are inconclusive or conflicting, or are of
unknown quality and cannot support the level of confidence required to characterize the
region into one of the other three categories;
AND/OR
(2) Either the measurements of the potential adverse effects on living resources are too
limited temporally and/or spatially, are inconclusive or conflicting, or are of unknown
quality and cannot support the level of confidence required to characterize the region into
one of the other three categories;
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An area can be characterized into this category if either condition (1) or condition (2) is met, or if
both conditions (1) and (2) are met.
C.2. Making a Characterization
Using these guidelines and the available data, each workgroup member weighed the
evidence for each segment and, using their best professional judgement, they made their
characterizations. The process for evaluating and integrating data was designed to standardize
the characterization process as much as possible and the workgroup sought to be as consistent in
its judgements as possible. It is important to note that making a characterization is not a
standardized process where anyone looking at a set of data and applying the general
characterization criteria and decision rules would come up with the same characterization. Each
workgroup member had to evaluate the data, recognizing certain realities such as:
the overall paucity of chemical contaminant data in the tidal rivers,
the paucity of effects data in many segments,
a database weighted heavily towards sediment data,
the different mixes of data in different rivers of the Bay,
the quality of data, and
the inherent uncertainties in different thresholds.
Each workgroup member evaluated the data independently and filled out a report card
that justified their characterization of the segment. The workgroup met 6 times from August
1998 through April 1999 to come to consensus on each characterization. In most cases, the
initial votes were not unanimous. Those with the minority vote were given the choice of either
presenting their justification to the workgroup, or allowing the majority to present their case.
After this discussion, workgroup members placed a final vote. The majority vote became the
final characterization and the minority members were allowed to caveat the characterization with
a narrative description. This process for finalizing characterizations was very effective in
building workgroup consensus and comfort with the final decisions. The strength of this
characterization is represented by the workgroup's technical knowledge of chemical contaminant
data, its diversity of interests, and its ability to discuss the data and reach a consensus on all
characterizations.
C.3. Insights Into Making Characterizations
There were some general "rules of thumb" that emerged in the characterization process
that are worth noting:
Exposure data alone can drive a characterization. The Workgroup discovered, in the
absence of effects data, that chemistry data could be compelling enough to indicate the
presence or absence of a chemical contaminant problem if the data were widespread,
recent, and pertained to persistent, bioaccumulative, and toxic chemicals. The workgroup
found cases where the chemistry data were compelling enough to characterize an entire
segment as an Area with Low Probability for Adverse Effects or an Area of Emphasis on
the basis of sediment chemistry data alone. The workgroup's confidence in these
characterization could be bolstered in the future with effects data.
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Confidence in effects data can drive a characterization. Concurrently collected
exposure and effects data from the Chesapeake Bay Ambient Toxicity Assessment
Program was compelling evidence for characterizing a segment as an Area of Emphasis
or an Area with Low Probability for Adverse Effects even if it was somewhat spatially or
temporally limited, due to the workgroup's high level of confidence in the data.
Additional assessments to increase spatial coverage of the data is necessary to confirm
these initial characterizations.
Benthic community data cannot drive a characterization. Because interpretative tools
have not been developed to distinguish chemical contaminant-related benthic community
degradation from degradation caused by other stressors such as low dissolved oxygen,
benthic community data cannot drive a characterization, but can be used in support of
making a characterization.
Information such as landuse and loadings data can be helpful in making
characterizations. The workgroup let the ambient data drive their characterization and
tried not to let their personal knowledge of a given area influence their characterizations.
However, they found that sometimes considering information about landuse, loadings,
and historical sources sometimes helped them to finalize a characterization. For example,
if an area has known kepone problems from historical sources, but the ambient data do
not include kepone measurements, then data may be insufficient in making a
characterization. Another example is if a segment was lacking data in one area and the
landuse around the entire segment was thought to be similar, the workgroup may infer
that similar ambient contaminant conditions exist in the unsampled area.
Several segments have localized problems. Several segments had specific localized
contamination problems that weren't reflective of the overall condition of the segment,
but should be addressed in future management and monitoring efforts. These localized
problem areas were noted in the workgroup's characterization, but most often did not
drive the characterization.
In some cases, the workgroup chose to characterize a segment as an Area with
Insufficient or Inconclusive Data until all available data have been collected. In some
cases, where data were currently being collected for a particular segment and would be
available in 1999 or early 2000, the workgroup decided to characterize it as an Area with
Insufficient or Inconclusive Data, pending the new data.
IV. REVIEW OF CHARACTERIZATION WORKPLAN AND RESULTS
The Chesapeake Bay Program's Scientific and Technical Advisory Committee (STAC)
technical reviewed a final draft of 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". Appendix D includes the
STAC review and the Toxics Subcommittee's response to the review. STAC reviewed the 1995
Chesapeake Bay Chemical Contaminant Geographical Targeting Protocol [2], which is the
22
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foundation for this effort. The STAC has received progress reports throughout the
characterization process, either through presentations to STAC or the Implementation
Committee. The Regional Focus Workgroup Chair presented a final briefing to the STAC on
March 25, 1999. The STAC members' reaction was very positive and they raised no concerns
about the technical merit of the effort.
The technical workplan also was reviewed by the Toxics Subcommittee, Regional Focus
Workgroup, and two technical reviewers from the US Environmental Protection Agency. The
Implementation Committee was briefed on the characterization process throughout the effort.
Additionally, a presentation was developed to aid workgroup members in communicating the
process and results to the managers on the Implementation Committee to ensure buy-in from
each of the participating agencies and institutions. Managers and communicators from Maryland
and Virginia state agencies were further briefed on this effort and the results in 1999.
The results of the characterization are summarized in a public report [1]. The Bay
Program signatory jurisdictional representatives on the Implementation Committee and the key
Principals' Staff Committee liaisons reviewed this report. Additionally, a community expert
panel and the Chesapeake Bay Program Office's Communications Team reviewed the public
report and results to ensure that the information presented was useful and relevant to
stakeholders.
V. IMPLICATIONS OF THE CHARACTERIZATION
Through the characterization process, the Bay's tidal rivers were classified 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. In the 1994
basinwide toxics strategy, the CBP signatories have committed to take the following actions
based on the characterization results:
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 effects.
Take actions necessary to ensure future protection of Areas with Low Probability for
Adverse Effects.
Initiate necessary assessments in Areas with Insufficient or Inconclusive Data.
Within six months of each subsequent review of available data, management and
assessment actions will be identified and implemented in specific regions of the Bay. 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 Bay Program will also use the characterization to inform
the public, local communities, and watershed associations about the chemical contaminant
conditions in their rivers so that they can take additional actions to protect or restore their rivers.
The characterization gives the State/District partners base information to allow them to conduct
23
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the more detailed risk assessment analysis, site specific analysis, and source assessment studies
which may be necessary before regulatory actions can be taken.
The Chesapeake Executive Council directed the Bay Program to reevaluate and revise the
1994 basinwide toxics strategy in 1999. This characterization, coupled with the 1999 Toxics
Loadings and Release Inventory, will be used to set new toxics reduction and prevention goals
for beyond the year 2000.
VI. UPDATES TO CHARACTERIZATION
The characterization of each segment will be reevaluated every three years using data
collected since the previous evaluation, as committed to within the 1994 Chesapeake Bay
Basinwide Toxics Reduction and Prevention Strategy. To prepare for future updates to the
characterization, the Bay Program will continue to acquire and load any existing, recent, relevant
chemical contaminant and biological data. Additionally, the Bay Program will direct further
assessments in the Areas with Insufficient or Inconclusive Data and those areas where data are
needed to strengthen the initial characterization. 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.
Recommendations for Future Updates to Characterization
Specific recommendations for improving subsequent characterizations are based on the
data and interpretative tool limitations highlighted in this report. To address data limitations, the
Bay Program will continue its data acquisition efforts to acquire all relevant, recent, available
information and direct assessments in particular areas to address any remaining data gaps. In
addition to improving coverage of data, the Bay Program will work to encourage improving the
interpretative tools (i.e., thresholds) for evaluating the data. The following are specific
recommendations for future updates to the characterization:
Improve spatial and temporal coverage of exposure and effects data through data
acquisition efforts.
S Through implementation of the Chesapeake Information Management System
(CEVIS) and building partnerships with state agencies and research institutions,
continue to acquire existing and future chemical contaminant exposure and effects
data for future characterization updates. Acquisition of currently available data
will be focused on filling in data gaps in the Areas with Insufficient or
Inconclusive Data and other areas where characterizations need to be strengthened
with additional data.
S Work with communities, local governments, and watershed associations to
acquire additional data to strengthen characterization in the future.
S Consider the feasibility of acquiring and interpreting fish abnormality data and
waterfowl/wading bird contaminant concentrations data in future
characterizations.
24
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Conduct monitoring, assessments, and research to support future updates. 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 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.
S If all available chemical data are not sufficient to characterize a segment, then
implement monitoring priorities defined in the Chesapeake Bay Toxics
Monitoring Strategy [18] to fill in data gaps, reduce the number of Areas with
Insufficient or Inconclusive Data, and strengthen the other characterizations.
S Increase spatial coverage of ambient toxicity testing through the enhancement of
state monitoring programs.
S Consider using a random sampling design for gathering data so that data from
particular sites are more likely to be representative of the entire segment sampled.
S Require the collection and reporting of acid volatile sulfides, simultaneously
extractable metals, and total organic carbon in conjunction with metals sediment
analysis and total organic carbon in conjunction with organic contaminant
sediment analysis.
S Identify those chemicals which may be problematic to the Bay due to their use,
toxicity or persistence but are not included in our current monitoring because they
have not been measured. These chemicals can be targeted for additional
monitoring to provide enough data to assess whether they are causing effects in
the Bay.
S Encourage more speciation measurements to determine the "free" form of a
contaminant that is bioavailable so that toxicity can be better predicted.
S Encourage research through the Chesapeake Bay Environmental Effects
Committee Toxics Research Program and other research programs to determine
the extent to which and how low level chemical contaminant exposure (including
the potential for additive and synergistic effects from multiple chemical
contaminants) poses a risk to the Bay's living resources. The characterization is
based on the best available thresholds. We do not know what, if any, the effect is
from long term exposure at chemical contaminant levels that are below these
thresholds.
Update and improve tools for interpreting exposure and effects data.
S Continually update water quality, sediment, and fish tissue thresholds as new
thresholds become available, including the application of guidelines that consider
additive effects of contaminants with similar modes of action.
S Explore the utility of using site-specific or Bay Program segment-specific total
organic carbon data for sediment thresholds that are dependent on total organic
carbon. Work with MD Geological Survey, Chesapeake Bay benthic monitoring
investigators, and the US Army Corps of Engineers to acquire total organic carbon
data. This may be difficult, given the fine scale spatial variability in sediment
type.
25
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S Explore the AQUIRE database and other sources of empirically-based
bioconcentration factors and quantitative structure activity relationship (QSAR)
predicted bioconcentration factors for relevant thresholds to use in future
characterization updates for those chemical contaminants without thresholds listed
in Appendices B and C.
S Refine the decision rules for how to include a diversity of toxicity data from
national and state programs.
S Develop interpretative tools to determine chemical contaminant-related benthic
degradation.
S Explore interpretative tools that link fish community data and finfish/shellfish
abnormality data to chemical contaminants for use in characterization updates.
Develop additional characterization rules and guidelines based on the 1999
characterization.
S Conduct quantitative analysis of characterization results to determine the
feasibility of developing quantitative guidelines for making future
characterizations. For example, determine if a certain density of data or number
of threshold exceedences was needed to characterize an area into a particular
category.
26
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REFERENCES
1. Chesapeake Bay Program (1999) Targeting Toxics: A Characterization Report - A Tool
for Directing Management & Monitoring Actions in the Chesapeake Bay's Tidal Rivers.
US EPA CBPO, Annapolis, Maryland.
2. Chesapeake Bay Program (1995) Chesapeake Bay Chemical Contaminant Geographical
Targeting Protocol, Chesapeake Bay Basinwide Toxics Reduction and Prevention
Strategy Commitment Report. US EPA CBPO, Annapolis, Maryland.
3. Chesapeake Bay Program (1999) 1999 Chesapeake Bay Basinwide Toxics Loading and
Release Inventory. US EPA CBPO, Annapolis, Maryland.
4. Chesapeake Bay Program (1994) Chesapeake Bay Basinwide Toxics Reduction Strategy
Reevaluation Report. US EPA CBPO, Annapolis, Maryland.
5. Chesapeake Executive Council. (1993) Directive No. 93-2 Toxics Reduction Strategy
Reevaluation. Annapolis, Maryland.
6. Chesapeake Executive Council (1994) Chesapeake Bay Basinwide Toxics Reduction and
Prevention Strategy. Annapolis, Maryland.
7. Great Lakes Water Quality Board Surveillance Workgroup (1987) Guidance on
Characterization of Toxic Substances Problems in Areas of Concern in the Great Lakes
Basin. A Report from the Surveillance Workgroup based on the recommendations from
the monitoring in Areas of Concern workshop held at Canada Centre for Inland Waters,
October 3-4, 1985, Windsor, Ontario.
8. Hartig, J.H. and N.L. Law (1993) Institutional Frameworks to Direct the Development
and Implementation of Remedial Action Plans. Based on a March 1993 roundtable
cosponsored by Environment Canada and US Environmental Protection Agency, in
cooperation with Wayne State University.
9. PTI Environmental Services (1990) The Urban Bay Action Program Approach: A
Focused Toxics Control Strategy. Report prepared for the US Environmental Protection
Agency, Region 10, Office of Puget Sound.
10. US EPA (1997) The Incidence and Severity of Sediment Contamination in Surface Waters
of the United States, Volume 1: National Sediment Quality Survey, EPA 823-R-97-006,
September 1997.
11. Chesapeake Bay Program (1998) Ambient Toxicity Testing in Chesapeake Bay - Year 6
Report, EPA 903/R/98/017, CBP/TRS 210/98, September 1998, US EPA CBPO,
Annapolis, Maryland.
27
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12. Chesapeake Bay Program (1997), Sediment Threshold Compendium, Draft Report, US
EPA CBPO, Annapolis, Maryland.
13. Chesapeake Bay Program (1998), Fish Tissue Threshold Compendium., Draft Report, US
EPA CBPO, Annapolis, Maryland.
14. Ranasinghe, J.A., S.B. Weisberg, D.M. Dauer, L.C. Schaffner, RJ. Diaz, and J.B.
Frithsen (1993). Chesapeake Bay Benthic Community Restoration Goals. Report prepared
for the US Environmental Protection Agency, Chesapeake Bay Program Office,
Annapolis, Maryland and The Governors Council on Chesapeake Bay Research Fund and
the Chesapeake Bay Research and Monitoring Division, Maryland Department of Natural
Resources, Tidewater Administration, Annapolis, Maryland.
15. Ranasinghe, J.A., S.B. Weisberg, J. Gerritsen, and D.M. Dauer (1993) Assessment of
Chesapeake Bay Benthic Macroinvertebrate Resource Condition in Relation to Water
Quality and Watershed Stressors. Report prepared for The Governors Council on
Chesapeake Bay Research Fund and the Chesapeake Bay Research and Monitoring
Division, Maryland Department of Natural Resources, Tidewater Administration,
Annapolis, Maryland.
16. Weisberg, S.B., Ranasinghe, J.A., Dauer, D.M., Schaffner, L.C., Diaz, R.J., and Frithsen,
J.B. (1997) An Estuarine Benthic Index ofBiotic Integrity (B-lBl)for Chesapeake Bay,
Estuaries, Vol. 20, No. 1, pp. 149 - 158.
17. Chesapeake Bay Program. (1992). Chesapeake Bay Dissolved Oxygen Goal for
Restoration of Living Resource Habitats, Chapter IV, CBP/TRS 88/93, EPA CBPO,
Annapolis, Maryland.
18. Chesapeake Bay Program (1999) Chesapeake Bay Toxics Monitoring Strategy. US EPA
CBPO, Annapolis, Maryland.
References for Appendix B
19. Pilli, A, B.R. Sheedy, and D. Grunwald (1992) AQUIRE: Aquatic toxicity Information
Retrieval Database: A Technical Support Document. US Environmental Protection
Agency, Environmental Research Laboratory-Duluth, Duluth, Minnesota.
20. Russom, C.L., E.B. Anderson, B.E. Greenwood, and A. Pilli. (1991) ASTER: an
integration of the AQUIRE database and the QSAR system for use in ecological risk
assessments. The Science of the Total Environment. 109/110:667-670.
21. Environmental Protection Agency (1993) Sediment Quality Criteria for the Protection of
Benthic Organisms: Acenaphthene, US EPA, Office of Water, Office of Science and
Technology, Heath and Ecological Criteria Division, Washington, D.C.
29
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22. US Environmental Protection Agency (1996) DRAFT: Derivation of EPA 's Sediment
Quality Advisory Levels, US EPA, Standards and Applied Science Division, Office of
Science and Technology, Washington, D.C.
23. Long, Edward R., Donald D. MacDonald, Sherri L. Smith, and Fred D. Calder (1995)
Incidence of Adverse Biological Effects within Ranges of Chemical Concentrations in
Marine andEstuarine Sediments" Env. Man., Vol. 19, No. 1, pp. 81-97.
24. Environment Canada (1996) Manuscript Report (unpublished). Proposed Canadian
Interim Sediment Quality Guidelines for the Protection of Aquatic Life. Guidelines
Division, Science Policy and Env. Qual. Branch, Eco. Science Dir., Env. Canada, Ottawa.
25. MacDonald, D.D. (1994) Development of an Approach to te Assessment of Sediment
Quality in Florida Coastal Waters. Florida Department of Environmental Regulation.
26. US Environmental Protection Agency (1993) Guidance for Assessing Chemical
Contaminant Data for Use in Fish Advisories, Volume /, Fish Sampling and Analysis,
EPA 823-R-93-002. US EPA, Office of Water, Washington, D.C.
30
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TABLE 4. GUIDELINES FOR INTERPRETING CHEMICAL CONTAMINANT DATA AND MAKING
TOXICS CHARACTERIZATION (refer to Sections III of technical workplanfor more information)
Water Column
Contaminant
Concentration
Bottom Sediment
Contaminant
Concentration
Finfish Tissue
Contamination
Shellfish Tissue
Contamination
Water Column Toxicity
Bottom Sediment
TOYIPITV
1 UAlUlLy
Benthic Community
S true turG
REGION OF CONCERN
Water column
concentrations exceed
current acute or chronic
EPA aquatic life criteria or
Bay states' water quality
standards for protection of
aquatic life or are above
laboratory concentrations
observed to cause acute or
chronic toxicity in aquatic
organisms.
AND/OR
Sediment contaminant
concentrations are above
thresholds associated with
probable or potential
adverse effects.
AND/OR
Edible portion of finfish
tissue contaminant
concentrations in resident,
non-migratory species
exceed levels required for
protection of human health
or restrictions on
harvest/consumption are in
place.
AND/OR
Shellfish tissue
contaminant concentrations
exceed levels required for
protection of human health
or restrictions on
harvest/consumption are in
place.
A ivm
AIM \j
Percent of ambient acute or
chronic effects differ
significantly from reference
areas/controls.
AND/OR
Percent of ambient acute or
chronic effects differ
significantly from reference
areas/controls.
AND/OR
Chesapeake Bay benthic
restoration goal index of 3
or less, where dissolved
oxygen can be eliminated
as the principal cause of
impact on the benthic
community.
AREA OF EMPHASIS
Water column
concentrations exceed
current acute or chronic
EPA aquatic life criteria
or Bay states' water
quality standards for
protection of aquatic life
or are above laboratory
concentrations observed
to cause acute or chronic
toxicity in aquatic
organisms.
AND/OR
Sediment contaminant
concentrations are above
thresholds associated with
probable or potential
adverse effects.
AND/OR
Edible portion of finfish
tissue contaminant
concentrations in resident,
non-migratory species
exceed levels required for
protection of human
health or restrictions on
harvest/consumption are
in place.
AND/OR
Shellfish tissue
contaminant
concentrations exceed
levels required for
protection of human
health or restrictions on
harvest/consumption are
in place.
A ivm /OT>
AIM \Ji UK
Percent of ambient acute
or chronic effects differ
significantly from
reference areas/controls.
AND/OR
Percent of ambient acute
or chronic effects differ
significantly from
reference areas/controls.
AND/OR
Chesapeake Bay benthic
restoration goal index of 3
or less, where dissolved
oxygen can be eliminated
as the principal cause of
impact on the benthic
community.
AREA WITH LOW
PROBABILITY FOR
ADVERSE EFFECTS
Water column
concentrations do not
exceed current acute or
chronic EPA aquatic life
criteria or Bay states' water
quality standards for
protection of aquatic life or
are not above laboratory
concentrations observed to
cause acute or chronic
toxicity in aquatic
organisms.
AND/OR
Sediment contaminant
concentrations are below
thresholds associated with
probable or potential
adverse effects.
AND/OR
Edible portion of finfish
tissue contaminant
concentrations in resident,
non-migratory species do
not exceed levels required
for protection of human
health and there are no
restrictions on
harvest/consumption in
place.
AND/OR
Shellfish tissue
contaminant concentrations
do not exceed levels
required for protection of
human health; there are no
restrictions on harvest or
consumption.
AMU/OR
rVll Ui W1V
Percent of ambient acute or
chronic effects do not differ
significantly from reference
areas/controls.
AND/OR
Percent of ambient acute or
chronic effects do not differ
significantly from reference
areas/controls.
AND/OR
Chesapeake Bay benthic
restoration goal index of
greater than 3, or index less
than 3 where dissolved
oxygen is identified as the
principal cause of impact
on the benthic community.
AREA WITH
INSUFFICIENT OR
INCONCLUSIVE DATA
Either no quality water
column concentration
data are available or data
are too limited or
inconclusive to
characterize area.
AND/OR
Either no quality
sediment contaminant
concentration data are
available or data are too
limited or inconclusive
to characterize area.
AND/OR
Either no edible portion
of finfish tissue
contaminant data are
available or data are too
limited or inconclusive
to characterize area.
AND/OR
Either no shellfish tissue
contaminant data are
available or data are too
limited or inconclusive
to characterize area.
A NT) /OR
Either no water column
toxicity data are
available or data are too
limited or inconclusive
to characterize area.
AND/OR
Either no sediment
toxicity data are
available or data are too
limited or inconclusive
to characterize area.
AND/OR
Either no data are
available on benthic
community structure or
data are too limited or
inconclusive to
characterize area.
0)
3
s
L 1
-------
Figure 1 - coming soon
-------
Figure 2: Water Chemical Concentration
Sampling Stations 1994 - 1998
Data Used in 1999 Toxics Characterization
20 Miles
"-O"
-------
Figure 3: Sediment Chemical Concentration
Sampling Stations 1984 - 1998
Data Used in 1999 Toxics Characterization
20 Miles
"-O"
-------
Figure 4: Finfish/Shellfish Tissue Chemical Concentration
Sampling Stations 1990 - 1997
Data Used in 1999 Toxics Characterization
-------
Figure 5,
Chesapeake Bay Ambient Toxicity
Assessment Program
Water/Sediment Sampling Stations
1990-1996
Hall clal (1998) Year 6 Rcpnrl Amhicnl Tnsicity Tc-slinu in Chesapeake Bay (1990-1996)
-------
Figure 6 - coming soon
-------
Figure 7.
Lower Potomac River (LE-2) random and fixed benthic
sampling locations with levels of dissolved oxygen for 1994
LEGEND
Severely degraded - random sampling
Degraded - random sampling
Meet; goal - random sampling
Severely degraded - Fixed sampling
Marginal - fixed sampling
DO < 2mg/l less than 10% of lime
DO < I mg/l moic than 10% of lime
d Miles
-------
APPENDIX A: SUMMARY OF REFERENCES IN TOXICS DATABASE
A-l
-------
References for the Data in the Toxics Database 17:50 Tuesday, May 25, 1999
R0000187
Sediment Survey of Priority Pollutants in the District of Columbia
Waters:Prepared for the Interstate Commission on the Potomac River
Basin, March 5, 1990
PREPARED FOR:Interstate Commission on the Potomac River Basin Rockville, MD
PREPARED BY:LTI, Limno-Tech Inc.
LTI, Limno-Tech Inc.
2395 Huron Pkwy
R0000209
1983 Crab Survey
Mary Jo Garreis, Deidre Murphy
Maryland Department of the Environment/Water Management Administration
Standards & Certification Division
R0000211
Shellstock Contaminant Monitoring Program
Mary Jo Garreis, Deidre Murphy, P.Distefano
Maryland Department of the Environment/Water Management Administration
Standards & Certification Division
R0000212
Basic Water Monitoring Program Fish Tissue Network
Mary Jo Garreis, Deidre Murphy
Maryland Department of the Environment/Water Management Administration
Standards & Certification Division
R0000238
Toxic Substances in Submerged Aquatic Vegetation Beds
January 1990
Jeffrey C. Cornwell and J. Court Stevenson
Horn Point Environmental Laboratories, University of Maryland
Center for Environmental and Estuatine Studies
-------
References for the Data in the Toxics Database 17:50 Tuesday, May 25, 1999
R0000241
Maryland Chesapeake Bay Sediment Toxicant Monitoring Program
Robert Magnien
Maryland Department of the Environment/Water Management Adminstration
Chesapeake Bay and Special Projects Program
R0000242
National Status & Trends Program for Marine Environmental Quality
Second Summary of Data on Chemical Contaminants in Sediment
from the Nationl Status and Trends Program
Dr. Thomas P. O'Connor, Manager
National Status and Trends Program
NOAA/National Ocean Service
U.S. Department of Commerce
R0000245
A Pilot Study for Ambient Toxicity Testing in Chesapeake Bay
Volume I Year I Report April, 1991.
Lenwood W. Hall Jr.; Michael C. Ziegenfuss; Steven A. Fisher; Raymond W.
Alden, III; Emily Deaver; Jay Gooch; Nikki Debert-Hastings.
CBP/TRS 64/91
R0000246
A Pilot Study for Ambient Toxicity Testing in Chesapeake Bay,
Volume II Year II Report November, 1992.
Lenwood W. Hall Jr.; Michael C. Ziegenfuss; Steven A. Fisher; Raymond W.
Alden, III; Emily Deaver; Jay Gooch; Nikki Debert-Hastings.
CBP/TRS 82/92
-------
References for the Data in the Toxics Database
R0003611
DEQ/EPA, Chesapeake Bay and Tributaries Study, '91
R0003612
DEQ, Elizabeth River Extra Study, '86
-------
References for the Data in the Toxics Database 17:50 Tuesday, May 25, 1999
R0003616
A Pilot Study for Ambient Toxicity Testing in Chesapeake Bay,
Year 3 Report, May 1994.
Lenwood W. Hall, Jr.; Michael C. Ziegenfuss; Ronald D. Anderson;
William D. Killen; Raymond W. Alden III; Peter Adolphson
CBP/TRS 116/94
R0003618
Chesapeake Bay Fall Line Toxics Monitoring Program: 1992 Interim Report
GMU (Dept. of Chemistry); MDE; USGS (Water Res. Div.) ; Metropolitan
Washington Council of Governments; Occoquan Watershed Monitoring Lab.
U.S. EPA Chespeake Bay Program, CBP/TRS 131/95, April 1994
R0003619
Inventory of Chemical Concentrations in Coastal and Estuatine
Sediments
Daskalis, K.D. and T.P. O'Conner. 1984.
U.S. Department of Commerce, National Oceanic and Atmospheric Admin.,
National Ocean Service, Office of Ocean Resources Conservation and
R0003620
Field assessment of striped bass, morone saxatilis, larval survival
as related to contaminants and changes in water quality parameters
Hall, L.W. 1984.
Johns Hopkins University, Applied Physics Laboratory, Aquatic
Ecology Section, Shady Side, Maryland
R0003621
In-situ investigations for assessing striped bass, morone saxatilis
larval and yearling survival as related to conaminants and changes in
water quality parameters-contaminants and water quality evaluations
Hall, L.W. 1985.
Johns Hopkins University, Applied Physics Laboratory, Aquatic
Ecology Section, Shady Side, Maryland
-------
References for the Data in the Toxics Database 17:50 Tuesday, May 25, 1999
R0003622
In-situ investigations for assessing striped bass, morone saxatilis,
prolarval and yearling survival as related to contaminants and water
quality parameters in the Potomac River-contaminant and water quality
Hall, L.W., W.S. Hall, S.J. Bushong. 1986
Johns Hopkins University, Applied Physics Laboratory, Aquatic
Ecology Section, Shady Side, Maryland
R0003623
Mobile on-site and in-situ striped bass contaminant studies in the
Choptank River and Upper Chesapeake Bay-annual contaminant and water
quality evaluations in east coast striped bass habitats
Hall, L.W., S.J. Bushong, M.C. Ziegenfuss, W.S. Hall. 1987.
Johns Hopkins University, Applied Physics Laboratory, Aquatic
Ecology Section, Shady Side, Maryland
R0003624
Striped bass contaminant and water quality studies in the Potomac
River and Upper Chesapeake Bay-annual contaminant and water quality
evaluations in east coast striped bass habitats
Hall, L.W. M.C. Zeigenfuss, S.J. Bushong, M.A. Unger. 1988.
Johns Hopkins University, Applied Physics Laboratory, Aquatic
Ecology Section, Shady Side, Maryland
R0003625
Striped bass contaminant and water quality studies in the Potomac
River and Upper Chesapeake Bay in 1989: Annual contaminant and water
quality evaluations in east coast striped bass habitats
Hall, L.W., M.C. Ziegenfuss, S.J. Bushong, J.A. Sullivan,
M.A. Unger. 1991.
University of Maryland System, Agricultural Experiment Station, Wye
Research and Education Center, Queenstown, MD
R0003626
In-situ striped bass contaminant and water quality studies in the
Potomac River and Upper Chesapeake Bay in 1990
quality evaluations in east coast striped bass habitats
Hall, L.W., M.C. Zeigenfuss, S.A. Fischer, J.A. Sullivan,
D.M. Palmer. 1992.
University of Maryland, Agricultural Experiment Station, Wye
Research and Education Center, Queenstown, MD.
-------
References for the Data in the Toxics Database 17:50 Tuesday, May 25, 1999 8
R0003627
PESTICIDE MONITORING OF OYSTERS, 1974-1995
VIRGINIA DIVISION OF SHELLFISH SANITATION
-------
References for the Data in the Toxics Database 17:50 Tuesday, May 25, 1999 8
R0003636
Agricultural Pesticide Residues in Oysters and Water From Two Chesapeake
BAY TRIBUTARIES
S.J. Lehotay
J.A. Harman-Fetcho
USDA, Agricultural Research Services
Beltsville Agric. Res. Center
R0003638
Ambient Toxicity Testing in Chesapeake Bay
Year 6 Report
7/1/98
Lenwood W. Hall, Jr.
Ronald D. Anderson
Univ. of Maryland System
Agricultural Experiment Station
R0003639
Ambient Toxicity Testing in Chesapeake Bay
Year 5 Report
2/1/98
Lenwood W. Hall, Jr.
Ronald D. Anderson
Chesapeake Bay Program
R0003640
A Pilot Study for Ambient Toxicity Testing in Chesapeake Bay
Year 4 Report
4/1/97
Lenwood W. Hall, Jr.
Ronald D. Anderson
Chesapeake Bay Program
-------
References for the Data in the Toxics Database
R0003644
EMAP- Estuaries Program Level Database
1993 Virginian Province
Sediment Chemistry Data
Charles Strobel, US EPA NHEERL-AED
Melissa Hughes
R0003645
VA Ambient Monitoring Network, 1992- 1998.
STORET Retrieval
Retreival Date 12/10/98
R0003646
Sediment Contamination & Toxicity Assessments in support of the development
of Benthic Restoration Goals & Sediment Quality Criteria. Final Report to
VDEQ. 29.pgs. 1998.
Dauer, D.M.
R0003648
Nitrate and Pesticide Data for Waters of the Mid-Atlantic
U.S. Geological Survey Open-File Report 98-
Data download from usgs.gov/maia/swdata
Matthew J. Ferrai
Scott W. Ator
U.S. Department of the Interior, U
USEPA
R0003650
Virginia Toxics Database
Data: 1979-1993
Virginia Department of Environmental Quality
Water Division - Office of Environmental Research
and Standards
-------
References for the Data in the Toxics Database
R0003737
Paxtuxent River Trace Element Data
Dr. Gerhardt F. Reidel
Academy of Natural Sciences
Estuarine Research Center
-------
APPENDIX B: Characterization Decision Rules
Overview
Through many deliberations, the Regional Focus Workgroup reached consensus on a set
of decision rules to provide a uniform and unbiased method for screening data for each segment.
The decision rules and data analysis displays provided a standardized output of information for
the Workgroup to consider as they made the characterizations. Ultimately, the Workgroup's
characterizations were based on the weight of evidence and their best professional judgement.
In order to characterize a segment into one of the four categories, the exposure and effects
data were compared to contaminant thresholds or control conditions, respectively. These
decision rules list the threshold sets used for interpreting the exposure and effects data. For each
exposure data type (i.e., water, sediment, or tissue chemical contaminant concentration data), the
Workgroup chose multiple sets of thresholds because no one set of thresholds covers all
chemicals measured and because of the diversity of opinions in the scientific community
regarding the utility of each threshold set. The workgroup ranked the thresholds appropriate for
each data type based upon the level of confidence in the ability of the threshold to predict effects
or protect living resources and on the scientific validity of the approach used to develop the
threshold. Appendix C provides a complete listing of all thresholds used by chemical. The
decision rules also include uniform methods for interpreting the benthic and ambient toxicity
effects data.
In addition to identifying which thresholds to use, the decision rules also serve as a
screening tool for electronically sorting data into four "levels of contamination" to make it easier
for the workgroup members to integrate the data in a given area. Levels of contamination were
assigned to each sampling station and data type based on which thresholds were exceeded and
the magnitude of the exceedence. The four levels of contamination represent evidence for
characterizing a segment as a Region of Concern (Level 1), Area of Emphasis (Level 2), Area
with Low Probability for Adverse Effects (Level 3), and Area with Insufficient or Inconclusive
Data (Level 4). Sub-levels are included for some media to facilitate the characterization. It is
important to note that classifying a station for one or more media at a particular level will not
necessarily result in characterizing the entire segment into a particular category. The final
characterization will be based on the integration of all data from all stations in the segment.
Levels of Contamination
Level 1
S Indicates probable contaminant effects.
S Primarily supports characterizing segment as Regions of Concern or Areas of Emphasis.
S Rules designed to make this group exclusive, so that only stations with the possibility of
probable effects would be classified into this level.
Level 2
S Indicates potential contaminant effects.
B-l
-------
S Primarily supports characterizing segment as Areas of Emphasis.
S Rules designed to make this group inclusive, so that any station with the potential of
having potential effects would be listed in this level.
Level 3
S Indicates low probability for contaminant effects.
S Rules designed to make this group exclusive, so that only stations with evidence of a low
probability for effects would be classified into this level.
S Primarily supports characterizing segment as Areas With Low Probability of Adverse
Effects.
Level 4
S Indicates data are insufficient or inconclusive to place the station into one of the other
levels, due to the absence of any data, the absence of appropriate thresholds for data that
have been collected, conflicting or inconclusive data, or data of unknown quality.
S Primarily supports characterizing segment as Areas with Insufficient or Inconclusive
Data.
B-2
-------
Water Column Contaminant Concentration Data
Observed ambient water column chemical contaminant concentrations were compared
with relevant chemical contaminant concentrations known to be protective of most aquatic
organisms (i.e., EPA aquatic life criteria, respective state water quality standards) or with other
relevant thresholds above which adverse effects to aquatic organisms have been observed and
documented (i.e., laboratory-based chemical specific toxicity tests). In the event where EPA
criteria differed from state standards or standards differed among states, the Workgroup decided
on which threshold was most appropriate to use. The threshold sets used for interpreting the
water chemistry data are listed below with the thresholds having typically higher values listed
first. Sub-level designations were given based on the Workgroup's judgement of the severity of
exceedences of different thresholds. For example, an exceedence of an acute criterion (Level
l.A.) was considered more serious than an exceedence of the lower chronic criterion value (Level
I.B.).
Thresholds
Set 1: EPA Acute Water Quality Criteria or State Standard
Set 2: EPA Chronic Water Quality Criteria or State Standard
Decision Rules
Level 1
A. Exceedence of Set 1 threshold for any chemical.
B. Exceedence of Set 2 threshold for any chemical.
Level 2
Exceedences of threshold Sets 1 and 2 can provide evidence for either probable or
potential contaminant effects. No additional appropriate thresholds were available
for a Level 2 designation. In the absence of EPA criteria for measured chemicals,
data were compared to benchmarks in the AQUIRE database (a source of
empirically-based bioconcentration factors and quantitative structure activity
relationship (QSAR) predicted bioconcentration factors [19,20]). Oftentimes
these benchmarks were not appropriate for estuarine environments and
exceedences of these benchmarks did not drive any characterizations. Therefore,
these thresholds were removed from the analysis until more appropriate and
relevant thresholds are determined.
Level 3
A. No exceedences of any Set 1 or Set 2 thresholds for any chemical.
Level 4
A. Above detection limit data without thresholds for comparison.
B. Below detection limit data without thresholds for comparison.
C. No water contaminant concentration data collected at station.
Note:
Anytime a freshwater threshold was used, in the absence of a saltwater/estuarine
threshold, the results were "flagged" in the data analysis tables.
B-3
-------
Sediment Contaminant Concentration Data
Observed ambient sediment contaminant concentrations were compared with contaminant
threshold concentrations associated with adverse biological effects. Sediment quality threshold
values were compiled from peer-reviewed literature and technical reports, summarized in a
sediment threshold compendium [12] and stored on the Chesapeake Bay Program Toxics
Database. The most appropriate (i.e., higher level of certainty and most applicable to the Bay
region estuarine organisms) threshold values were selected for comparison to sediment
contaminant data.
The threshold sets used for interpreting the sediment chemistry data are listed below with
the thresholds having typically higher values listed first. Sub-level designations were given
based on the Workgroup's level of confidence in the ability of the threshold to predict effects or
protect living resources. For example, an exceedence of a NOAA ER-M would be given a higher
level designation (2. A.) than an exceedence of the lower value NOAA ER-L (2.B.). A
"concentration:threshold" ratio (hereafter Ratio) was used as a measure of the magnitude of an
exceedence and was calculated by dividing the measured concentration by the threshold value. If
the concentration was greater than or equal to two, the workgroup's confidence that the threshold
was actually exceeded was higher. Since the Workgroup's confidence in an exceedence of
threshold Set 1, Set la, and Set 2 (where Ratio > 2) was the same and they could not distinguish
between the severity of the exceedences, an exceedence of these thresholds was given the same
Level l.A. designation. See Appendix C for actual threshold values.
Thresholds
Set 1: EPA Equilibrium Partitioning-based Sediment Quality Criteria
(EqP based SQC) [21]
Set la: EPA Equilibrium Partitioning-based Sediment Quality Advisory Level
(EqP-based SQAL) [22]
Set 2: Lowest of the NOAA Effects Range-Median (ER-M), Environment
Canada Probable Effects Level (PEL), and MacDonald PEL [23,24,25]
Set 3: Lowest of the NOAA Effects Range-Low (ER-L), Environment Canada
Threshold Effects Level (TEL), and the MacDonald TEL [23,24,25].
Decision Rules
Level 1
A.I Exceedence of Set 1 threshold for any chemical.
A.2 Exceedence of Set la threshold for any chemical.
A.3 Exceedence of Set 2 threshold for any chemical, Ratio > 2.
Level 2
A. Exceedence of Set 2 threshold for any chemical, Ratio < 2.
B. Exceedence of Set 3 threshold for any chemical, Ratio > 2.
C. Exceedence of Set 3 threshold for any chemical, Ratio < 2.
B-4
-------
Level 3
A. No exceedences of any threshold for any chemicals.
Level 4
A. Above detection limit data without thresholds for comparison.
B. Below detection limit data without thresholds for comparison.
C. No sediment contaminant concentration data collected at station.
B-5
-------
Evaluating Polychlorinated Biphenyls (PCBs) in Sediment
The sum of the PCB arochlors and the sum of the PCB congeners were compared to the
total PCB thresholds listed below. In the cases where multiple concentration values were
reported for the same PCB arochlor or congenor for the same study, date, and location (i.e.,
replicates or split samples), the geometric mean of these values was calculated first, and then the
concentrations for all PCB arochlors or congeners were summed and compared to the thresholds.
This analysis was conducted for three different scenarios where any below detection limit values
were (1) set to zero, (2) set to one-half the detection limit, and (3) set to the detection limit.
Thresholds
NOAAER-M for total PCBs (ISOppb)
NOAAER-L for total PCBs (22.7 ppb)
Decision Rules
Level 1
Exceedence of NO AA ER-M for total PCB s.
Level 2
Exceedence of NOAA ER-L for total PCBs.
Level 3
No exceedence of NOAA ER-L or ER-M for total PCB s.
B-6
-------
Finfish/Shellfish Tissue Chemical Contaminant Concentration Data
Measurements of the edible portion of finfish tissue contaminant concentrations in
resident, non-migratory species and shellfish tissue contaminant concentrations were compared
with thresholds associated with the protection of human health. Available human health
consumption threshold values were compiled from national and worldwide literature and
government documents and summarized in a fish tissue threshold compendium [13] and stored
on the Chesapeake Bay Program Toxics Data Base. The most appropriate (i.e., higher level of
certainty) threshold values were selected for comparison to fish tissue contamination data.
Existing chemical contaminant-related fish consumption advisories and bans were also used as
evidence in making a characterization.
The threshold sets used for interpreting the finfish/shellfish tissue data are listed below
with the thresholds having typically higher values listed first. Sub-level designations were given
based on the Workgroup's level of confidence in the ability of the threshold to predict effects or
protect living resources. When the Workgroup's confidence in an exceedence of threshold was
indistinguishable (as in the case of an exceedence of a Set 2 and Set 3 threshold), the same sub-
level designation was used (Level 2.A.). See Appendix C for actual threshold values.
Thresholds
Set 1: Food and Drug Administration (FDA) Action Levels [13]1
Set 2: Food and Drug Administration (FDA) Levels of Concern [13]1
Set 3: Environmental Protection Agency (EPA) Screening Levels [26]2
Decision Rules
Level 1
A. 1 Exceedence of FDA Action Level for any chemical
Level 2
A. 1 Exceedence of FDA Level of Concern for any chemical.
A.2 EPA Screening Level for any chemical.
Level 3
A. No exceedences of any FDA or EPA thresholds for any chemical.
Level 4
A. Above detection limit data without thresholds for comparison.
B. Below detection limit data without thresholds for comparison.
C. No finfish/shellfish chemical contaminant data collected at station.
1 See reference [13] for assumptions made in calculating threshold.
2
Assumes adult population weight of 70 kg, 70 year life time, mean daily consumption rate of 6.5 g/day.
B-7
-------
Note: If a given chemicals has a 90th percentile FDA levels of concern and a mean FDA
levels of concern, the 90th percentile level was used. For those chemicals that
have more than one threshold for different ages of fmfish/shellfish, the lowest
threshold was used. Unless the threshold specifies, the threshold was applied to
all tissue types (finfish and shellfish).
B-8
-------
Evaluating Polychlorinated Biphenyls (PCBs) in Fish Tissue
The sum of the PCB arochlors and the sum of the PCB congeners were compared to the
total PCB thresholds listed below. In the cases where multiple concentration values were
reported for the same PCB arochlor or congenor for the same study, date, and location (i.e.,
replicates or split samples), the geometric mean of these values was calculated first, and then the
concentrations for all PCB arochlors or congeners were summed and compared to the thresholds.
This analysis was conducted for three different scenarios where any below detection limit values
were (1) set to zero, (2) set to one-half the detection limit, and (3) set to the detection limit.
Thresholds
FDA Action Level for total PCBs (2.0 ppm)
EPA Screening Level for total PCBs (0.01 ppm)
Decision Rules
Level 1
Exceedence of FDA Action Level for total PCBs.
Level 2
Exceedence of EPA Screening Level for total PCBs.
Level 3
No exceedence of FDA Action Level or EPA Screening Level for total PCBs.
B-9
-------
Benthic Community Data
Benthic community data (i.e., species number, species diversity, and biomass) collected
for the Bay Program were summarized into a Benthic Index of Biotic Integrity (B-IBI) that
indicates benthic community health [14,15,16]. A B-IBI of greater than 3 indicates the benthic
community meets or exceeds the restoration goal (a benthic community characteristic of a non-
degraded bottom habitat in Chesapeake Bay); an index of 2 to 3 indicates a degraded benthic
community; and an index of less than 2 indicates a severely degraded benthic community. Only
data for regions where low dissolved oxygen conditions could be eliminated as the principle
cause of benthic community degradation were used as supportive evidence in making a
characterization. Sub-level designations were given based on the B-IBI score. For example, a B-
IBI score indicating a degraded community was given a sub-level of 2. A. while a B-IBI score
indicating a marginal community was given a sub-level of 2.B.
Thresholds
Benthic Index of Biotic Integrity (B-IBI) Restoration Goals
Decision Rules
Level 1
A. Severely Degraded (B-IBI <=2), sufficient dissolved oxygen.
Level 2
A. Degraded (B-IBI: 2-<2.6), sufficient dissolved oxygen.
B. Marginal (B-IBI: 2.6-<3), sufficient dissolved oxygen.
Level 3
Meets Goal (B-IBI: > 3)
Level 4
No benthic data available at station.
B-10
-------
Ambient Toxicity Test Data
Ambient water column and bottom sediment toxicity data from the Chesapeake Bay
Ambient Toxicity Assessment Program have already been interpreted by assigning a "degree of
toxicity" to a sampled area. These degrees of toxicity are used in interpreting the data.
Workgroup members also evaluated the sediment and water toxicity index values which provide
a relative measure of toxicity of a given site compared to all other sites sample during the
program. Toxicity data collected through other programs were evaluated for statistically
significant differences between the observed adverse effects (i.e., survival, growth, reproduction)
and reference area or control toxicity test results.
Degrees of Toxicity
The "degree of toxicity" of water and sediment for the Chesapeake Bay Ambient Toxicity
Assessment Program was determined by a "weight of evidence" approach based on the toxicity
index value, the percentage of significant toxic impairments observed (i.e., endpoints such as
survival, growth, and reproduction that were significantly different from the control), and
whether or not chemical contaminants measured were above certain thresholds.
Great toxicity: Those areas with "great" toxicity have the highest toxicity index values,
roughly a quarter of the endpoints are significantly different from controls,
and chemical contaminants that exceed thresholds.
Low to Moderate toxicity: Those areas with low to moderate toxicity have lower toxic index
values than areas with great toxicity, but still show a substantial
percentage of endpoints that are significantly different from
controls, and oftentimes some of the chemical contaminant
measured exceed thresholds.
Low but Significant toxicity: Those areas that exhibit toxicity that is statistically significant, but
are not thought to be ecologically significant.
No Significant toxicity: Those areas where chemical contamination does not appear to be a
problem.
Thresholds
For the Chesapeake Bay Ambient Toxicity Assessment Program (ATP) results:
reported "degree of toxicity."
For other available toxicity test results: percentages of endpoints significantly different
from reference, or statistical comparison of toxicity test results with control/reference
test.
B-ll
-------
Decision Rules
Level 1
A. "Great" sediment AND water column toxicity (ATP) or at least 2
significant sediment and water tests each (non-ATP).
B.
Level 2
A.
B.
C.
D.
Level 3
A.
B.
Level 4
"Great" sediment OR water column toxicity (ATP) or at least 2 significant
sediment or water tests (non-ATP).
"Low to Moderate" sediment AND water column toxicity (ATP) or any
one significant sediment and water test each (non-ATP).
"Low to Moderate" sediment OR water column toxicity (ATP) or any one
significant sediment or water test each (non-ATP).
"Low but Significant" sediment AND water column toxicity (ATP).
"Low but Significant" sediment OR water column toxicity (ATP).
"No Significant" sediment AND water column toxicity observed.
"No Significant" sediment OR water column toxicity observed.
No toxicity data available at station.
B-12
-------
APPENDIX C: Chemical Thresholds Used to Interpret Data for Characterization
The Regional Focus Workgroup used a number of different threshold sets against which
to compare the exposure data to in conducting the characterization, as described in the decision
rules (Appendix B). This appendix includes the comprehensive list of all available thresholds
listed in Appendix B for water, sediment, and fish tissue data. These threshold lists include all
available thresholds, regardless of whether there are corresponding data in the Chesapeake Bay
Toxics Database for each of the chemicals.
There are 2 sets of water column thresholds:
Set 1 - EPA/State acute water quality criteria
Set 2 - EPA/State chronic water quality criteria
There are 4 sets of sediment thresholds:
Set 1 - SQCs - EqP based thresholds
Set la - SQALs - EqP based thresholds
Set 2 - ERMs/PELs
Set 3 - ERLs/TELs
There are 4 sets offish tissue thresholds:
Set 1 - FDA action levels
Set 2a - FDA levels of concern - 90th percentile
Set 2b - FDA levels of concern - mean
Set 3 - EPA Screening levels
The threshold sets listed above are included in this appendix as a separate table. Each of
the tables are presented in a similar manner:
The chemical is identified by chemical name and then by Chemical Abstract Service
number (CAS Number).
The threshold is then listed, followed by the units. It should be noted that the thresholds
are not all expressed in the same units.
The type of water for which the threshold was derived is identified as freshwater,
saltwater, estuarine. A footnote appears at the bottom of each table explaining all valid
entries for this column.
Water column thresholds only - please note that where available, saltwater water quality
criteria were selected over freshwater water quality criteria for comparison against water
column data in the Chesapeake Bay rivers. In the absence of a saltwater water quality
criteria, a freshwater water quality criteria was chosen and the value was flagged.
Fish tissue threshold only - the species for which the threshold is considered valid is
presented (e.g., Crustacea, Finfish, Mollusca).
The source of threshold is identified.
C-l
-------
Acenaphthene
Acrolein
Acrylonitrile
Aldrin
Antimony
Arsenic III
Arsenic V
BHC
Benzene
Benzidine
Beryllium
Cadmium
Carbon Tetrachloride
Chlordane
Chloride
Chlorinated Benzenes
Chlorine
Chloroform
Chlorophenol 2-
Chlorophenol 4-
Chlorophenol 4-Methyl-3-
Chlorpyrifos
Chromium (III)
Chromium (VI)
Copper
Cyanide
DDD 4,4-
DDE
DDT
Di-2-Ethylhexyl phthalate
Dichlorobenzenes
Dichloroethane 1,2-
Dichloroethylenes
Dichlorophenol 2,4-
Dichloropropane
Dichloropropene
Dieldrin
Dimethylphenol 2,4-
Dinitrophenol
Dinitrophenol 2,4
Dinitrotoluene
Dinitrotoluene 2,4-
Diphenylhydrazine 1,2-
Endosulfan
Endosulfan a-
Endosulfan b-
Endrin
Ethylbenzene
Fluoranthene
CAS
Number
000083329
000107028
000107131
000309002
007440360
022569728
017428410
000680731
000071432
000092875
007440417
007440439
000056235
000057749
CAS000337
007782505
000067663
000095578
000106489
000059507
002921882
016065831
007440473
007440508
000057125
000072548
000072559
000050293
000117817
025321226
000107062
025323303
000120832
026638197
026952238
000060571
000105679
025550587
000051285
025321146
000121142
000122667
000115297
000959988
033213659
000072208
000100414
000206440
Threshold
Value
970
55
7550
1.3
1500
69
2319
0.34
5100
2500
130
43
50000
0.09
860000
160
13
28900
4380
29700
30
0.01
10300
1100
6.1
1
3 . 6
14
0.13
400
1970
113000
224000
2020
10300
790
0.71
2120
^
7
590
330
270
0.03
0.03
0.03
0.03
430
40
Units
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
Water
Type
(1)
s
s
F
q
S
s
s
s
s
F
F
q
S
s
F
o
o
F
F
s
F
S
q
q
Flag
(2)
EPA
EPA
1 EPA
EPA
EPA
EPA
EPA
EPA
EPA
1 EPA
1 EPA
EPA
EPA
EPA
1 EPA
EPA
EPA
1 EPA
1 EPA
EPA
1 EPA
EPA
EPA
EPA
Threshold
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
S MD Acute
s
S
S
S
S
S
S
S
F
S
S
q
F
F
F
S
F
F
q
S
s
s
s
s
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
1 EPA
EPA
EPA
EPA
1 EPA
1 EPA
1 EPA
EPA
1 EPA
1 EPA
EPA
EPA
EPA
EPA
EPA
EPA
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
State
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Source
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Water Quality Criteria
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
-------
Water
Type
(1)
HEXACHLOROCYCLOHEXANE - BETA
HEXACHLOROCYCLOHEXANE - GAMMA
HEXACHLOROCYCLOHEXANE - TECHNI
Haloethers
Heptachlor
Heptachlor epoxide
Hexachlorobenzene
Hexachlorobutadiene
Hexachlorocyclopentadiene
Hexachloroethane
Isophorone
Lead
Mercury
Naphthalene
Nickel
Nitrate
Nitrobenzene
Nitrosamines
PCB-1016 (PCB)
PCB-1221 (PCB)
PCB-1232 (PCB)
PCB-1248 (PCB)
PCB-1254 (PCB)
PCB-1260 (PCB)
PCBs
Parathion
Pentachloroethane
Pentachlorophenol
Phenanthrene
Phenol
Phthalate esters
Polynuclear aromatic hydrocarb
Selenium
Silver
TCDD 2,3,7,8- (dioxin)
TRICHLOROPHENOL, 2,4,5-
Tetrachloroethane 1,1,2,2-
Tetrachloroethanes
Tetrachloroethylene
Tetrachlorophenol 2,3,5,6-
Thallium
Toluene
Toxaphene
Trichloroethane 1,1,1-
Trichloroethanes
Trichloroethylene
Zinc
000319857
000058899
000319868
CAS000409
000076448
001024573
000118741
000087683
000077474
000067721
000078591
007439921
007439976
000091203
007440020
014797558
000098953
035576911
012674112
011104282
011141165
012672296
011097691
011096825
001336363
000056382
000076017
000087865
000085018
000108952
CAS000407
CAS000340
007782492
007440224
001746016
000095954
000079345
025322207
000127184
000935955
007440280
000108883
008001352
000071556
025323891
000079016
007440666
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
1
1
1
1
1
1
1
1
1
1
1
1
1
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Acute
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
-------
Acenaphthene
Acrolein
Acrylonitrile
Antimony
Arsenic III
Benzene
Beryllium
Cadmium
Chlordane
Chloride
Chlorinated Benzenes
Chlorine
Chloroform
Chlorpyrifos
Chromium (III)
Chromium (VI)
Copper
Cyanide
DDT
Demeton
Di-2-Ethylhexyl phthalate
Dichlorobenzenes
Dichloroethane 1,2-
Dichlorophenol 2,4-
Dichloropropane
Dichloropropene
Dieldrin
Dinitrotoluene
Dinitrotoluene 2,4-
Endosulfan
Endosulfan a-
Endosulfan b-
Endrin
Fluoranthene
Guthion
HEXACHLOROCYCLOHEXANE - BETA
HEXACHLOROCYCLOHEXANE - GAMMA
HEXACHLOROCYCLOHEXANE - TECHNI
Haloethers
Heptachlor
Heptachlor epoxide
Hexachlorobenzene
Hexachlorobutadiene
Hexachlorocyclopentadiene
Hexachloroethane
Hydrogen sulfide
Iron
Lead
Malathion
CAS
Number
000083329
000107028
000107131
007440360
022569728
000071432
007440417
007440439
000057749
CAS000337
007782505
000067663
002921882
016065831
007440473
007440508
000057125
000050293
008065483
000117817
025321226
000107062
000120832
026638197
026952238
000060571
025321146
000121142
000115297
000959988
033213659
000072208
000206440
000086500
000319857
000058899
000319868
CAS000409
000076448
001024573
000118741
000087683
000077474
000067721
007783064
007439896
007439921
000121755
Threshold
Value
710
21
2600
500
36
700
5.3
9.3
0.004
230000
129
7.5
1240
0.0056
210
50
12
5.2
0.001
0.1
360
763
20000
365
3040
244
0.0019
370
230
0.0087
0.0087
0.0087
0.0023
16
0.01
0.08
0.08
0.08
122
0.0036
0.0036
3.68
9.3
5.2
540
2
1000
8.5
0.1
Units
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
Water
Type
(1)
S
F
F
q
S
s
F
S
s
F
S
s
F
s
F
C
F
F
S
s
S
F
F
F
S
F
s
S
F
q
S
s
s
s
s
F
F
F
F
s
S
F
F
F
F
s
F
S
S
Flag
(2) )
EPA
1 EPA
1 EPA
EPA
EPA
EPA
1 EPA
EPA
EPA
1 EPA
EPA
EPA
1 EPA
EPA
1 EPA
EPA
1 EPA
1 EPA
EPA
EPA
EPA
1 EPA
1 EPA
1 EPA
EPA
1 EPA
EPA
EPA
1 EPA
EPA
EPA
EPA
EPA
EPA
EPA
1 EPA
1 EPA
1 EPA
1 EPA
EPA
EPA
1 EPA
1 EPA
1 EPA
1 EPA
EPA
1 EPA
EPA
EPA
Thres
hold
Source
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
-------
Mercury
Methoxychlor
Mirex
Naphthalene
Nickel
PCBs
Parathion
Pentachloroethane
Pentachlorophenol
Phenanthrene
Phenol
Phosphorus (elemental)
Phthalate esters
Selenium
Silver
TCDD 2,3,7,8- (dioxin)
TRICHLOROPHENOL, 2,4,5-
Tetrachloroethane 1,1,2,2-
Tetrachloroethylene
Thallium
Toluene
Toxaphene
Trichloroethane 1,1,2-
Trichloroethylene
Trichlorophenol 2,4,6-
CAS
Number
007439976
000072435
002385855
000091203
007440020
001336363
000056382
000076017
000087865
000085018
000108952
007723140
CAS000407
007782492
007440224
001746016
000095954
000079345
000127184
007440280
000108883
008001352
000079005
000079016
000088062
007440666
Threshold
Value
0.02
0.03
0.001
620
8.3
0.03
0.01
281
7 . 9
4 .6
2560
0.1
3.4
71
0.92
0.00001
11
2400
450
40
5000
0.0002
9400
21900
970
86
Units
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
UG/L
Water
Type
(1)
s
s
c
F
S
s
F
S
S
q
F
S
s
s
s
F
C
F
S
F
S
S
F
F
F
s
Flag
(2) )
EPA
EPA
EPA
1 EPA
EPA
EPA
1 EPA
EPA
EPA
EPA
1 EPA
EPA
EPA
EPA
EPA
1 EPA
EPA
1 EPA
EPA
1 EPA
EPA
EPA
1 EPA
1 EPA
1 EPA
EPA
Thres
hold
Source
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Chronic
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Water
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Quality
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
Criteria
-------
IThresholds used for comparison to data in the Toxics Database
Sediment Thresholds, Set 1: SQCs - EqP based thresholds
10:34 Friday, April 16, 1999
ACENAPHTHENE
DIELDRIN
ENDRIN
FLUORANTHENE
PHENANTHRENE
Threshold
Value
TOGFLAG
EPA (1993), EqP, ACEN.
EPA (1993), EqP, DIELDRIN
EPA (1993), EqP, ENDRIN
EPA (1993), EqP, FLUOR.
EPA (1993), EqP, PHEN.
1 - When necessary, thresholds have been converted to PPB assuming 2% total organic carbon
2 - Water type values include: freshwater (FW), saltwater (SW), estuarine (E), fresh and saltwater (FS)
and estuarine and salt (ES).
-------
IThresholds used for comparison to data in the Toxics Database
Sediment Thresholds, Set 1A: SQALs - EqP based thresholds
10:34 Friday, April 16, 1999 2
1,1, 1-TRICHLOROETHANE
1,1,2,2-TETRACHLOROETHANE
1,2,4-TRICHLOROBENZENE
1,2-DICHLOROBENZENE
1,3-DICHLOROBENZENE
1,4-DICHLOROBENZENE
4-BROMOPHENYL PHENYL ETHER
BENZENE
BHC, DELTA
BHC, GAMMA (LINDANE)
BIPHENYL
BUTYL BENZYL PHTHALATE
CHLOROBENZENE
DI-N-BUTYL PHTHALATE
DIAZINON
DIBENZOFURAN
DIETHYL PHTHALATE
ENDOSULFAN MIXED ISOMERS
ENDOSULFAN-ALPHA
ENDOSULFAN-BETA
ETHYLBENZENE
FLUORENE
HEXACHLOROETHANE
MALATHION
METHOXYCHLOR
NAPHTHALENE
PENTACHLOROBENZENE
TETRACHLOROETHENE
TETRACHLOROMETHANE
TOLUENE
TOXAPHENE
TRIBROMOMETHANE
TRICHLOROETHENE
XYLENE, M
000071556
000079345
000120821
000095501
000541731
000106467
000101553
000071432
000319868
000058899
000092524
000085687
000108907
000084742
000333415
000132649
000084662
000115297
000959988
033213659
000100414
000086737
000067721
000121755
000072435
000091203
000608935
000127184
000056235
000108883
008001352
000075252
000079016
000108383
Threshold
Value
17
160
920
34
170
35
130
5.7
13
0.37
110
1100
82
1100
0.19
200
63
0.54
0.29
1.4
480
54
100
0 . 067
1.9
47
69
53
120
89
10
65
210
2 . 5
Units
(1)
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
UG/GOC
Water
Type
(2)
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
Threshold
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
Source
(1996) ,
(1996) ,
(1996) ,
(1996) ,
(1996) ,
(1996) ,
(1996) ,
(1996) ,
(1996) ,
(1996),
(1996) ,
(1996) ,
(1996) ,
(1996) ,
(1996) ,
(1996) ,
(1996) ,
(1996) ,
(1996) ,
(1996) ,
(1996) ,
(1996) ,
(1996) ,
(1996) ,
(1996) ,
(1996) ,
(1996) ,
(1996) ,
(1996) ,
(1996) ,
(1996) ,
(1996) ,
(1996) ,
(1996) ,
SQALs
SQALs
SQALs
SQALs
SQALs
SQALs
SQALs
SQALs
SQALs
SQALs
SQALs
SQALs
SQALs
SQALs
SQALs
SQALs
SQALs
SQALs
SQALs
SQALs
SQALs
SQALs
SQALs
SQALs
SQALs
SQALs
SQALs
SQALs
SQALs
SQALs
SQALs
SQALs
SQALs
SQALs
1 - When necessary, thresholds have been converted to PPB assuming 2% total organic carbon
2 - Water type values include: freshwater (FW), saltwater (SW), estuarine (E), fresh and saltwater (FS)
and estuarine and salt (ES).
-------
IThresholds used for comparison to data in the Toxics Database
Sediment Thresholds, Set 2: ERM/PELs
10:34 Friday, April 16, 1999
2-METHYLNAPHTHALENE
ACENAPHTHENE
ACENAPHTHYLENE
ANTHRACENE
ARSENIC
BENZO(A)ANTHRACENE
BENZO(A)PYRENE
BHC, GAMMA (LINDANE)
BIS(2-ETHYLHEXYL) PHTHALATE
CADMIUM
CHLORDANE
CHROMIUM
CHRYSENE
COPPER
DDD-P,P
DDE-P,P
DDT, TOTAL
DDT-P,P
DIBENZ(A,H)ANTHRACENE
DIELDRIN
ENDRIN
FLUORANTHENE
FLUORENE
HEPTACHLOR EPOXIDE
LEAD
MERCURY
NAPHTHALENE
NICKEL
PAH, HIGH MOLECULAR WEIGHT
PAH, LOW MOLECULAR WEIGHT
PAHS, TOTAL
PCBS, TOTAL
PHENANTHRENE
PYRENE
SILVER
ZINC
CAS
Number
000091576
000083329
000208968
000120127
007440382
000056553
000050328
000058899
000117817
007440439
000057749
007440473
000218019
007440508
000072548
000072559
CAS000111
000050293
000053703
000060571
000072208
000206440
000086737
001024573
007439921
007439976
000091203
007440020
CAS000460
CAS000461
000061789
001336363
000085018
000129000
007440224
007440666
Threshold
Value
201
88.9
128
245
41.6
693
763
0. 99
2647
4.21
4.79
160
846
108
7.81
2 7
46.1
4.77
135
4.3
62.4
1494
144
2.74
112
0.69
391
42.8
6676
1442
16770
180
544
1398
1.77
271
Units
(1)
NG/G
NG/G
NG/G
NG/G
UG/G
NG/G
NG/G
NG/G
NG/G
UG/G
NG/G
UG/G
NG/G
UG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
UG/G
UG/G
NG/G
UG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
UG/G
UG/G
Water
Type
(2)
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
SE
SE
FS
FS
FS
FW
FS
FS
FW
FS
FS
FS
FS
FS
FS
FS
SE
FS
FS
FS
FS
MACDONALD
MACDONALD
MACDONALD
MACDONALD
MACDONALD
MACDONALD
MACDONALD
MACDONALD
MACDONALD
MACDONALD
MACDONALD
MACDONALD
MACDONALD
MACDONALD
MACDONALD
NOAA (1995), ERM
NOAA (1995), ERM
MACDONALD (1994),
MACDONALD (1994),
MACDONALD (1994),
ENVIRONMENT CANADA
MACDONALD (1994
MACDONALD (1994
ENVIRONMENT CANADA
MACDONALD (1994),
MACDONALD
MACDONALD
MACDONALD
MACDONALD
MACDONALD
MACDONALD
NOAA (1995), ERM
MACDONALD (1994),
MACDONALD (1994),
MACDONALD (1994),
MACDONALD (1994),
PEL
PEL
PEL
(1996) PEL
PEL
PEL
(1996) PEL
PEL
PEL
PEL
PEL
PEL
PEL
PEL
PEL
PEL
PEL
PEL
1 - When necessary, thresholds have been converted to PPB assuming 2% total organic carbon
2 - Water type values include: freshwater (FW), saltwater (SW), estuarine (E), fresh and saltwater (FS)
-------
IThresholds used for comparison to data in the Toxics Database
Sediment Thresholds, Set 3: ERL/TELs
10:34 Friday, April 16, 1999
2-METHYLNAPHTHALENE
ACENAPHTHENE
ACENAPHTHYLENE
ANTHRACENE
ARSENIC
BENZO(A)ANTHRACENE
BENZO(A)PYRENE
BHC, GAMMA (LINDANE)
BIS (2-ETHYLHEXYL) PHTHALATE
CADMIUM
CHLORDANE
CHROMIUM
CHRYSENE
COPPER
DDD-P,P
DDE-P,P
DDT, TOTAL
DDT-P,P
DIBENZ(A,H)ANTHRACENE
DIELDRIN
ENDRIN
FLUORANTHENE
FLUORENE
HEPTACHLOR EPOXIDE
LEAD
MERCURY
NAPHTHALENE
NICKEL
PAH, HIGH MOLECULAR WEIGHT
PAH, LOW MOLECULAR WEIGHT
PAHS, TOTAL
PCBS, TOTAL
PHENANTHRENE
PYRENE
SILVER
ZINC
000091576
000083329
000208968
000120127
007440382
000056553
000050328
000058899
000117817
007440439
000057749
007440473
000218019
007440508
000072548
000072559
CAS000111
000050293
000053703
000060571
000072208
000206440
000086737
001024573
007439921
007439976
000091203
007440020
CAS000460
CAS000461
000061789
001336363
000085018
000129000
007440224
007440666
Threshold
Value
20 . 2
6.71
5.87
46.9
7.24
74 .8
88.8
0.32
182
0.676
2.26
52.3
108
18.7
1.22
2.07
1.58
1.19
6.22
0.715
2.67
113
19
0.6
30.2
0.13
34 .6
15.9
655
312
1684
21.5
86.7
153
0.73
124
Units
(1)
NG/G
NG/G
NG/G
NG/G
UG/G
NG/G
NG/G
NG/G
NG/G
UG/G
NG/G
UG/G
NG/G
UG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
UG/G
UG/G
NG/G
UG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
UG/G
UG/G
Water
Type
(2)
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
SE
FS
FS
FS
FW
FS
SE
FW
FS
FS
FS
FS
FS
FS
FS
SW
FS
FS
SW
FS
MACDONALD
MACDONALD
MACDONALD
MACDONALD
MACDONALD
MACDONALD
MACDONALD
MACDONALD
MACDONALD
MACDONALD
MACDONALD
MACDONALD
MACDONALD
MACDONALD
MACDONALD
MACDONALD
NOAA (1995) ,
MACDONALD
MACDONALD
MACDONALD
ENVIRONMENT CANADA (1996) TEL
MACDONALD (1994), TEL
NOAA (1995) , ERL
ENVIRONMENT CANADA (1996) TEL
MACDONALD (1994), TEL
(1994),
(1994),
(1994),
(1994),
(1994),
(1994),
ENVIRONMENT CANADA (1996) TEL
MACDONALD (1994), TEL
MACDONALD (1994), TEL
ENVIRONMENT CANADA (1996) TEL
MACDONALD (1994), TEL
(1994) ,
(1994) ,
(1994) ,
(1994) ,
(1994) ,
(1994) ,
(1994) ,
(1994) ,
(1994) ,
(1994) ,
(1994) ,
(1994) ,
(1994) ,
(1994) ,
(1994) ,
(1994) ,
) , ERL
(1994) ,
(1994) ,
(1994) ,
TEL
TEL
TEL
TEL
TEL
TEL
TEL
TEL
TEL
TEL
TEL
TEL
TEL
TEL
TEL
TEL
TEL
TEL
TEL
TEL
TEL
TEL
TEL
TEL
TEL
1 - When necessary, thresholds have been converted to PPB assuming 2% total organic carbon
2 - Water type values include: freshwater (FW), saltwater (SW), estuarine (E), fresh and saltwater (FS)
-------
IThresholds used for comparison to data in the Toxics Database
Tissue Thresholds, Set 1: FDA Action Levels
10:34 Friday, April 16, 1999
Chemical
Name
ALDRIN
ALDRIN
ALDRIN
CHLORDANE
CHLORDANE
CHLORDANE
CHLORDECONE (KEPONE)
CHLORDECONE (KEPONE)
CHLORDECONE (KEPONE)
DDE
DDE
DDE
DDT
DDT
DDT
DIELDRIN
DIELDRIN
DIELDRIN
HEPTACHLOR
HEPTACHLOR
HEPTACHLOR
HEPTACHLOR EPOXIDE
HEPTACHLOR EPOXIDE
HEPTACHLOR EPOXIDE
MERCURY
MERCURY
MERCURY
MIREX
MIREX
MIREX
TDE
TDE
TDE
CAS
Number
000309002
000309002
000309002
000057749
000057749
000057749
000143500
000143500
000143500
000072559
000072559
000072559
000050293
000050293
000050293
000060571
000060571
000060571
000076448
000076448
000076448
001024573
001024573
001024573
007439976
007439976
007439976
002385855
002385855
002385855
000072548
000072548
000072548
Threshold
Value
300
300
300
300
300
300
300
300
300
5000
5000
5000
5000
5000
5000
300
300
300
300
300
300
300
300
300
1
1
1
100
100
100
5000
5000
5000
Units
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
UG/G
UG/G
UG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPM)
(PPM)
(PPM)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
Water
Type
(1)
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
Species
Type
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
Threshold
USFDA,
USFDA,
USFDA,
USFDA,
USFDA,
USFDA,
USFDA,
USFDA,
USFDA,
USFDA,
USFDA,
USFDA,
USFDA,
USFDA,
USFDA,
USFDA,
USFDA,
USFDA,
USFDA,
USFDA,
USFDA,
USFDA,
USFDA,
USFDA,
USFDA,
USFDA,
USFDA,
USFDA,
USFDA,
USFDA,
USFDA,
USFDA,
USFDA,
Source
ACTION
ACTION
ACTION
ACTION
ACTION
ACTION
ACTION
ACTION
ACTION
ACTION
ACTION
ACTION
ACTION
ACTION
ACTION
ACTION
ACTION
ACTION
ACTION
ACTION
ACTION
ACTION
ACTION
ACTION
ACTION
ACTION
ACTION
ACTION
ACTION
ACTION
ACTION
ACTION
ACTION
LEVELS
LEVELS
LEVELS
LEVELS
LEVELS
LEVELS
LEVELS
LEVELS
LEVELS
LEVELS
LEVELS
LEVELS
LEVELS
LEVELS
LEVELS
LEVELS
LEVELS
LEVELS
LEVELS
LEVELS
LEVELS
LEVELS
LEVELS
LEVELS
LEVELS
LEVELS
LEVELS
LEVELS
LEVELS
LEVELS
LEVELS
LEVELS
LEVELS
-------
IThresholds used for comparison to data in the Toxics Database
Tissue Thresholds, Set 2A: FDA Levels of Concern - 90th Percentile
10:34 Friday, April 16, 1999 2
III, TOTAL
III, TOTAL
007440382
007440382
007440439
007440439
016065831
016065831
007439921
007439921
007440020
007440020
Threshold
Value
Water
Type
(1)
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
CRUSTACEA
MOLLUSCA
CRUSTACEA
MOLLUSCA
CRUSTACEA
MOLLUSCA
CRUSTACEA
MOLLUSCA
CRUSTACEA
MOLLUSCA
-------
IThresholds used for comparison to data in the Toxics Database
Tissue Thresholds, Set 2B: FDA Levels of Concern - Mean
III, TOTAL
III, TOTAL
Threshold
Value
10:34 Friday, April 16, 1999
007440382
007440382
007440439
007440439
016065831
016065831
007439921
007439921
007440020
007440020
Water
Type
(1)
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
CRUSTACEA
MOLLUSCA
CRUSTACEA
MOLLUSCA
CRUSTACEA
MOLLUSCA
CRUSTACEA
MOLLUSCA
CRUSTACEA
MOLLUSCA
-------
IThresholds used for comparison to data in the Toxics Database
Tissue Thresholds Set 3: EPA Screening Levels
10:34 Friday, April 1
CADMIUM
CADMIUM
CADMIUM
CARBOPHENOTHION
CARBOPHENOTHION
CARBOPHENOTHION
CHLORDANE
CHLORDANE
CHLORDANE
CHLORPYRIFOS
CHLORPYRIFOS
CHLORPYRIFOS
DDT (TOTAL)
DDT (TOTAL)
DDT (TOTAL)
DIAZINON
DIAZINON
DIAZINON
DICOFOL
DICOFOL
DICOFOL
DIELDRIN
DIELDRIN
DIELDRIN
DIOXINS
DIOXINS
DIOXINS
DISULFOTON
DISULFOTON
DISULFOTON
ENDOSULFAN
ENDOSULFAN
ENDOSULFAN
ENDRIN
ENDRIN
ENDRIN
ETHION
ETHION
ETHION
HEPTACHLOR EPOXIDE
HEPTACHLOR EPOXIDE
HEPTACHLOR EPOXIDE
HEXACHLORBENZENE
HEXACHLORBENZENE
HEXACHLORBENZENE
LINDANE
LINDANE
LINDANE
MERCURY
MERCURY
CAS
Number
007440439
007440439
007440439
000786196
000786196
000786196
000057749
000057749
000057749
002921882
002921882
002921882
CAS000111
CAS000111
CAS000111
000333415
000333415
000333415
000115322
000115322
000115322
000060571
000060571
000060571
001746016
001746016
001746016
000298044
000298044
000298044
000115297
000115297
000115297
000072208
000072208
000072208
000563122
000563122
000563122
001024573
001024573
001024573
000118741
000118741
000118741
000058899
000058899
000058899
007439976
007439976
Threshold
Valu
10
10
10
1000
1000
1000
80
80
80
30000
30000
30000
300
300
300
900
900
900
10000
10000
10000
^
^
7
700
700
700
500
500
500
20000
20000
20000
3000
3000
3000
5000
5000
5000
10
10
10
70
70
70
80
80
80
0
0
e Units
.0
.0
.0
.0
.0
.0
. 0
. 0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
. 0
.0
.0
.0
.0
.0
. 0
. 0
.0
.0
.0
.0
.0
. 0
.0
.0
.0
.0
.0
.0
. 0
.6
.6
UG/G
UG/G
UG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
NG/G
UG/G
UG/G
(PPM)
(PPM)
(PPM)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPM)
(PPM)
Water
Type
(1)
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
Species
Type
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
Threshold
Source
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
-------
IThresholds used for comparison to data in the Toxics Database
Tissue Thresholds Set 3: EPA Screening Levels
Threshold
Value
2000.0
2000.0
2000.0
800 . 0
800.0
800.0
10.0
10.0
10.0
50.0
50.0
50.0
1000.0
1000.0
1000.0
100 .0
100.0
100.0
10:34 Friday, April If.
MERCURY
MIREX
MIREX
MIREX
OXYFLUORFEN
OXYFLUORFEN
OXYFLUORFEN
PCBS (TOTAL POLYCHLORINATED BI
PCBS (TOTAL POLYCHLORINATED BI
PCBS (TOTAL POLYCHLORINATED BI
SELENIUM
SELENIUM
SELENIUM
TERBUFOS
TERBUFOS
TERBUFOS
TOXAPHENE
TOXAPHENE
TOXAPHENE
007439976
002385855
002385855
002385855
042874033
042874033
042874033
001336363
001336363
001336363
007782492
007782492
007782492
013071799
013071799
013071799
008001352
008001352
008001352
Water
Type
(1)
(PPM)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPM)
(PPM)
(PPM)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
(PPB)
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
FS
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
CRUSTACEA
FINFISH
MOLLUSCA
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
USEPA,
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
SCREENING
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
VALUES
-------
APPENDIX D: 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 in 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
D-l
-------
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
D-2
-------
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.
D-3
-------
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
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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.
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
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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.
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).
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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.
Page-specific comments / 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.
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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?
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.
Sincerely,
Bob Summers
Chair, Toxics Subcommittee
Maryland Department of the Environment
Attachment
cc: Jonathan Phinney, Chair of Review Panel/Caryn Boscoe, STAC
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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
governmental and academic level to address Bay-wide issues, will the gaps in data
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coverage and gaps in our knowledge of the distribution and extent of toxic effects be
filled."
1. 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 Basimvide Toxics Reduction and
Prevention Strategy) or for periodic updates as new data become available (an alternative
strategy to triennial updates).
RE: "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."
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
Concur.
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RE: Management Tool
1st 1J 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 1J (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 Bay Basinwide 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 1| (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.
2ndU (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 IV 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
[sediment/water] was found to cause adverse effects on Chesapeake Bay organisms
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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 fully 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,
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
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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 1994 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
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
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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.
Bullet 4: "Repeated 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.,
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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: "(!) 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
of Bay..."
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 mainstem as 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
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.
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Bullet 2: "How will PCBs be quantified? ... Why was the Workgroup's confidence in using
a total PCB 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 al.,
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
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
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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.
BulletS:
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.
BulletS:
See explanation in Bullet 1.
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.
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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.
Bullet 12:
To clarify this sentence we added the following text: "(eg, lack of pesticide data in
highly agricultural areas would tend to drive a classification towards an Area with
Insufficient or Inconclusive
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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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