vvEPA
United States
Environmental Protection
Agency
Mid-Atlantic Integrated
Assessment (MAIA)
Estuaries 1997-98
Summary Report
Environmental Conditions in the
Mid-Atlantic Estuaries
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1, Executive Summary
Welcome to the Summary Report on the
Mid-Atlantic Integrated Assessment Estuaries
(MAIA-E). In this report we present a summation
of data collected in the environmental assessment
of mid-Atlantic estuaries conducted during the
summers of 1997-98. Over a dozen state and
federal environmental organizations participated
in the assessment and in the preparation of this
report. We hope this collaboration has helped
produce a summary that is relevant and useful.
The main objective of this report is to present
environmental data measured in the MAIA-E
program. We focus on several issues of wide-
spread interest: How prevalent is eutrophication
in mid-Atlantic estuaries? How contaminated are
the sediments? Are estuarine communities in the
sediments and water column disrupted by human
practices? Are the fish and shellfish we eat
contaminated?
The summary was written with three distinct
audiences in mind: (1) environmental managers
who are responsible for identifying and fixing
problems in estuaries; (2) concerned citizens
who are curious how estuaries operate and are
concerned how "their" estuary compares with
neighboring systems; and (3) researchers who
wish to know what type of data are available from
the MAIA program. Thus, a second objective of
the report is to present the MAIA assessment
information in a manner useful to all readers.
The mid-Atlantic estuaries fall naturally into
four geographical regions: the Delaware Estuary;
the Chesapeake Bay; the coastal bays in
Maryland and Virginia; and the Albemarle-
Pamlico Estuarine System (APES). In addition,
twelve smaller estuaries were monitored more
intensively to focus attention on a local scale.
Following are the main conclusions regarding
the environmental conditions in the mid-Atlantic
estuaries.
Eutrophication
There are ample signs of eutrophication in the
mid-Atlantic estuaries. In the region overall,
about 15-20% of estuarine area is affected by
high concentrations of nutrients, organic-rich
sediments, and oxygen-depleted waters. A third of
the estuarine area shows elevated concentrations
of chlorophyll a, and water visibility is less
than arm's length in half of the estuaries. These
symptoms of eutrophication vary widely among
estuaries.
In the Delaware Estuary, the urban Delaware,
Schuylkill, and Salem Rivers have high levels
of nutrients that are two to three times greater
than elsewhere in the mid-Atlantic region. High
levels of chlorophyll a are evident in parts of the
Delaware and Salem Rivers. But the pigment is
generally low in Schuylkill River and much of
Delaware Bay, perhaps because of limited light
availability. Oxygen depletion is not a major issue
in the Delaware Estuary.
In Chesapeake Bay, nutrient concentrations are
high in the Patuxent, Potomac, Severn, and South
Rivers. Most estuaries in Chesapeake Bay show
elevated levels of chlorophyll a, an indication
of extensive algal blooms. Chesapeake Bay
also displays the highest incidence of oxygen
depletion in the mid-Atlantic region — over half
of the area in the mainstem and Severn, South,
and Patuxent Rivers report oxygen values below 5
mg/L (in many places, below 2 mg/L).
Other eutrophication "hot spots" include
Sinepuxent Bay and parts of the Neuse River,
where elevated levels of nutrients and organic
matter are evident. The coastal bays are nutrient-
rich and especially turbid, but signs of organic
enrichment are generally absent. Otherwise,
estuarine systems with easy access to the sea, e.g.,
Delaware Bay, the lower Chesapeake mainstem,
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and open parts of Albemarle-Pamlico Sounds,
are relatively less affected by the symptoms of
eutrophication.
Sediment Contamination
Most of the mid-Atlantic estuaries have sediments
that are contaminated with metals and toxic
organic compounds. In the MAIA region overall,
30 to 40% of estuarine area exceeds effects range-
low (ERL) or effects range-median (ERM) limits
(ecologically-based guidelines) for metals and
organic toxicants.
The Delaware, Schuylkill, and Salem Rivers, the
upper Chesapeake mainstem, and the Severn
and South Rivers are especially polluted by
metals. Arsenic, nickel, mercury and zinc are the
metals most often exceeding ERL or ERM limits.
Mercury contamination is evident in Chowan
River and other parts of the APES.
Harmful concentrations of polycyclic aromatic
hydrocarbons (PAHs), pesticides, DDT, and
polychlorinated biphenyls (PCBs) are present in
regions of the Delaware and Schuylkill Rivers,
the upper Chesapeake mainstem, and the Severn
and South Rivers. The organic toxicants are less
pervasive than metals throughout the region.
Only 1% of the region's sediments are
characterized as toxic, based on the survivability
of sediment organisms exposed to the sediments.
Toxicity is noted in the heavily contaminated
Delaware and Schuylkill Rivers, and in the
moderately polluted Chowan River. Other highly
contaminated systems, such as the Severn and
South Rivers are not characterized as toxic by this
test.
Condition of the Living
Resources
The MAIA program places particular emphasis
on the condition of communities in the water
and sediments — the living resources. A "benthic
community index", based on the diversity of
organisms and abundance of pollution tolerant
organisms in sediments, is used to evaluate
the condition of estuaries. The index rated
as "poor" several of the estuaries that also
show extensive signs of eutrophication and
sediment contamination, including Schuylkill,
Severn, South, and Potomac Rivers. But the
list also includes estuaries which show low or
moderate environmental degradation.
Over 3000 fish from 76 sites were examined for
signs of pathology. Only five abnormalities are
noted. However, when the edible portions of
fish and shellfish from the same sites were
analyzed for concentrations of metals and organic
toxicants, 65% of the tests revealed levels large
enough to present risk to human consumers.
Arsenic and PCBs were the only toxicants found
in harmful amounts.
Changes Over Time
The Environmental Monitoring and Assessment
Program (EMAP) conducted a similar
environmental study in the Virginian Province
(VP) in the summers of 1990-93. This study
region included part of the region surveyed by
the MAIA program in 1997-98. For estuaries
assessed in both the EMAP and MAIA studies,
it is therefore possible to look for changes
that occurred between 1990-93 and 1997-98. In
most cases, the uncertainty in the respective
measurements is too large to permit drawing clear
conclusions. However, the following conclusive
changes are evident:
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Organic contamination in the Delaware River
sediments worsened. The percentage of estuarine
area failing any organic ERM criteria increased
from 2 + 11% in 1990-93 to 34 + 10% in 1997.
It is not certain whether this increase represents
recent contamination or the dispersal of prior
contamination over additional area.
Metal contamination in the Chesapeake Bay
sediments worsened. The percentage of estuarine
area failing any ERM criteria increased from 5
+ 3% in 1990-93 to 22 + 5% in 1997. Similar
changes occurred in the Chesapeake mainstem
and Potomac River.
The benthic community in the Chesapeake Bay
sediments showed increased degradation. The
percentage of estuarine area with a benthic index
< 0 (an indication of degradation) increased from
23 + 5% in 1990-93 to 37 + 5% in 1997.
Sediment toxicity diminished slightly in the
Chesapeake Bay. The percentage of estuarine area
failing the amphipod survival assay decreased
from 6 + 3% in 1990-93 to 0.3 + 0.3% in 1997.
Similar changes are noted in the Chesapeake
mainstem.
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EPA/620/R-02/003
December 2002
Mid-Atlantic Integrated Assessment
(MAI A) Estuaries 1997-98
Summary Report
Environmental Conditions in the Mid-Atlantic Estuaries
Compiled and Edited by:
U.S. Environmental Protection Agency
Office of Research and Development
National Health and Environmental Effects Research Laboratory
Atlantic Ecology Division (AED)
27 Tarzwell Drive
Narragansett, Rl 02882
and
U.S. Environmental Protection Agency
Region III
1650 Arch Street
Philadelphia, PA 19103-2029
T£^ Printed on chlorine free 100% recycled paper with
100% post-consumer fiber using vegetable-based ink.
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Notice
The information in this report was funded in part by the United States Protection Agency (Environmental
Monitoring and Assessment Program, Office of Research and Development) through the Atlantic Ecology
Division. This report was subject to EPA's peer and administrative review and external review, and has
received approval for publication as an EPA document. Mention of trade names or commercial products
does not constitute endorsement or approval for use.
The suggested citation for this report is: USEPA 2002. Mid-Atlantic Integrated Assessment 1997-98
Summary Report, EPA/620/R-02/003. U.S. Environmental Protection Agency, Atlantic Ecology Division,
Narragansett, RI.
Key Words: Mid-Atlantic Integrated Assessment; MAIA; Environmental Monitoring and Assessment
Program; EMAP; Delaware Estuary; Chesapeake Bay; Maryland and Virginia coastal bays; Albemarle-
Pamlico Estuarine System; APES; probabilistic sampling design; estuarine condition; eutrophication;
sediment contamination; impairment to biological communities; total nitrogen; total phosphorus;
chlorophyll a; total organic carbon; Secchi depth; dissolved oxygen; metal and organic ERL and ERM
exceedances; sediment toxicity; benthic community index; fish species diversity; fish abnormalities; fish
and shellfish tissue contamination; Index of Environmental Integrity; environmental report card.
Abstract
During the summers of 1997-98, a consortium of federal and state environmental agencies conducted
the Mid-Atlantic Integrated Assessment Estuaries (MAIA-E) program to characterize the environmental
condition of the four major estuaries in the mid-Atlantic region of the United States. The assessed
estuaries were the Delaware Estuary, Chesapeake Bay, the coastal bays in Maryland and Virginia, and the
Albemarle-Pamlico Estuarine System. Twelve smaller estuaries were also monitored to focus attention on
systems at the local scale. Over 800 stations were selected at random and key properties were measured
in three estuarine components - the water column, the sediments, and the biological community. This
summary report examines thirteen measured or calculated parameters that serve as indicators of estuarine
conditions. Three important environmental issues are emphasized: eutrophication, contamination of the
sediments, and the impairment of the biological communities in the estuaries.
11
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Contents
Notice, Abstract ii
Figures v
Tables vi
Acknowledgments vii
1. Executive Summary 1
Eutrophication 1
Sediment Contamination 2
Condition of the Living Resources 2
Changes Over Time 2
2. Introduction 5
About Estuaries 5
Mid-Atlantic Estuaries 6
The MAIA Program 7
Report Organization 8
3. Methodology 11
Background 11
Field Activities in 1997 and 1998 11
MAIA Indicators 13
4. Eutrophication 17
Background 17
Eutrophication Indicators 18
Total Nitrogen in Surface Water 18
Total Phosphorus in Surface Water 22
Chlorophyll a in Surface Water 25
Total Organic Carbon in Sediments 28
Water Clarity (Secchi Depth) 29
Dissolved Oxygen in Bottom Water 32
Summary: Eutrophication 38
in
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Contents (con't)
5. Sediment Contamination 41
Background 41
Metal Contaminants in Sediments 41
Organic Contaminants in Sediments 45
Sediment Toxicity (Amphipod Survival) 48
Summary: Sediment Contamination 51
6. Condition of Living Resources 53
Background 53
Condition of the Benthic Community (Benthic Index) 53
Number of Fish Species 56
Fish Abnormalities 57
Contamination of Fish and Shellfish Tissue 57
Summary: Conditions of the Living Resources 60
7. Summary of Conditions 63
Environmental Report Card 63
Change in Conditions: 1990-93 to 1997 65
Appendices 67
A. Sample Site Selection Design for MAIA Estuaries 1997-98 67
B. Methods and Indicators for MAIA Estuaries 1997-98 75
C. Criteria for Presenting Indicator Data 79
D. Values of Indicator Parameters 83
E. Tabulation of Condition Estimates 89
F. Statistical Correlation Coefficients Among Selected Indicators 93
G. Values of Condition Estimates in Common MAIA and EMAP Indicators 97
H. Index of Environmental Integrity for MAIA Estuaries 1997 99
I. Recommendations for Monitoring Program Design for Mid-Atlantic Estuaries 105
J. MAIA Estuaries Partners 109
References. .111
IV
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Figures
Figure 3-1 MAIA Stations Sampled During Summer 1997 in the MAIA Program 12
Figure 3-2 MAIA Stations Sampled During Summer 1998 in the MAIA Program 14
Figure 4-1 Concentration of Total Nitrogen in Surface Water 20
Figure 4-2 Concentration of Total Nitrogen in Intensively-Sampled Systems 21
Figure 4-3 Concentration of Total Phosphorus in Surface Water 23
Figure 4-4 Concentration of Total Phosphorus in Intensively-Sampled Systems 24
Figure 4-5 Concentration of Chlorophyll a in Surface Water 26
Figure 4-6 Concentration of Chlorophyll a in Intensively-Sampled Systems 27
Figure 4-7 Concentration of Total Organic Carbon in Surface Water 30
Figure 4-8 Concentration of Total Organic Carbon in Intensively-Sampled Systems 31
Figure 4-9 Secchi Depths as aMeasure of Water Clarity 33
Figure 4-10 Secchi Depth (Water Clarity) in Intensively-Sampled Systems 34
Figure 4-11 Concentration of Dissolved Oxygen in Bottom Water 36
Figure 4-12 Concentration of Dissolved Oxygen in Intensively-Sampled Systems 37
Figure 4-13 Summary of Eutrophication Indicators 39
Figure 5-1 ERL and ERM Exceedances for Metals in Sediments 43
Figure 5-2 ERL and ERM Exceedances for Metals in Intensively-Sampled Systems 44
Figure 5-3 ERL and ERM Exceedances for Organic Compounds in Sediments 46
Figure 5-4 ERL and ERM Exceedances for Organics in Intensively-Sampled Systems 47
Figure 5-5 Survival Rate of Ampelisca abdita Exposed to Sediments 49
Figure 5 -6 Survival Rate of Ampelisca abdita in Intensively-Sampled Systems 50
Figure 5-7 Summary of Sediment Contamination Indicators 52
Figure 6-1 Index of Benthic Community Condition (Benthic Index) 54
Figure 6-2 Index of Benthic Community Condition in Intensively-Sampled Systems 55
Figure 6-3 Number of Fish Species 58
Figure 6-4 Occurrence of Abnormalities in Fish 59
Figure 6-5 Contaminant Exceedances in Fish and Shellfish Tissue 61
Figure 7-1 Environmental Report Card 64
Figure 7-2 Changes in Environmental Conditions: 1990-93 to 1997 66
Figure H-l Environmental Report Card for Mid-Atlantic Estuaries 103
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Tables
Table 2-1 Mid-Atlantic Estuaries Highlighted in the MAIA Program and This Report 6
Table 2-2 Indicator Ranges Used to Define Assessment Categories 9
Table 3-1 Federal and State Partners in the Monitoring of Mid-Atlantic Estuaries 11
Table 3 -2 Estuarine Systems Selected for Spatial Intensification of Sampling 13
Table 3-3 Suite of Indicators Measured by Partners in MAIA Estuaries in 1997-98 15
Table 5-1 ERL and ERM Limits for Metals 42
Table 5-2 ERL and ERM Values for Organics 45
Table 6-1 USEPA Chemical Analytes and
Consumption Limits for Issuing Fish Advisories 60
Table A-l Initial Strata Used in Selection of
Sampling Sites for MAIA Estuaries 1997-98 70
Table A-2 Combinations of Strata Used to Produce Estimates for Geographic Areas 71
Table A-3 Design Specifics for MAIA Intensively-Sampled Small Estuarine Systems 72
Table A-4 Design Specifics for MAIA Randomly-Selected Small Estuarine Systems 72
Table A-5 Design Specifics for Delaware Estuary (River and Bay) 73
Table A-6 Design Specifics for Chesapeake Bay Mainstem 73
Table A-7 Design Specifics for Tributaries and Subsystems 74
Table A-8 Design Specifics for Albemarle-Pamlico Estuarine System 74
Table D-l Values of Indicator Parameters Representing Eutrophication 84
Table D-2 Concentrations of Metals in Sediments 85
Table D-3 Concentrations of Organic Toxicants in Sediments 86
Table D-4 Values of Indicator Parameters 87
Table E-l Percent Estuarine Area Falling in the
Condition Categories Used on the Maps in This Report 90
Table F-l Pearson Correlation Factors Among Indicated Indicators 94
Table G-l Changes in Environmental Conditions Measured
Between the 1990-1993 EMAP-VPand 1997MAIA-E Studies 97
Table H-l Assignment of Scores to Geographic Areas
for Each Indicator Based Upon Percent Area 100
Table H-2 Values for Index of Environmental
Integrity for MAIA Estuaries Geographic Areas 101
Table 1-1
Progression of EMAP Probability Sampling Designs in the Northeast 108
VI
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Acknowledgements
This report was prepared by the U.S. Environmental Protection Agency, Office of Research and
Development, National Health and Environmental Effects Research Laboratory, Atlantic Ecology
Division. The primary authors were John Kiddon, John Paul, Charles Strobel and Barbara Brown from
the Atlantic Ecology Division (AED), and Harry Buffum and Jane Copeland of Computer Sciences
Corporation (CSC). Significant efforts in the design, implementation, and analysis stages of the program
were also provided by Melissa Hughes, Patricia Martel, and Patricia DeCastro of CSC, and Patricia
Bradley, Don Cobb, Stephen Hale, Brian Melzian and Hal Walker of EPA/AED. Tony Olsen and Kevin
Summers were instrumental in developing the sampling design of the MAIA Estuaries program.
Juanita Soto of Technology Planning and Management Corporation (TPMC) was responsible for
formatting and painstakingly assembling this report.
Invaluable assistance in setting the direction of the report and in the interpreting and reviewing the report
was provided by the following individuals of the MAIA partner agencies: Rich Batiuk of the Chesapeake
Bay Program; Kent Price of the Delaware Center for the Inland Bays; Ben Anderson of the Delaware
Department of Natural Resources and Environmental Control; Ed Santoro of the Delaware River Basin
Commission; Carol Cain of the Maryland Coastal Bay Project; Rob Magnien and Bruce Michael of the
Maryland Department of Natural Resources; Jawed Hameedi, Jeff Hyland, and Andy Robertson from
the National Oceanic and Atmospheric Administration; Brian Sturgis of the National Park Service; Ed
Ambrogio, Charles App, Diana Esher, George Gibson, Rick Kutz, Tom DeMoss and Tom Pheiffer of
the U.S. Environmental Protection Agency; Eric Walbeck of TPMC; and Rick Hoffman, Donald Smith,
and Alex Barrow of the Virginia Department of Environmental Quality. Cover photo courtesy of Eric
Walbeck, TPMC.
The authors wish to acknowledge the comprehensive peer reviews provided by Fred Holland of the Marine
Resources Research Institute, Candace Oviatt of the University of Rhode Island, and Dennis Suszkowski
of the Hudson River Foundation. Additional reviews by Dan Campbell, Peg Pelletier, and Jerry Pesch of
the USEPA/AED are also gratefully appreciated.
Finally, we wish to acknowledge the tremendous effort of the field crews who braved long days, inclement
weather, and sea sickness to collect the thousands of samples for the MAIA program. Without their
dedication this report would not be possible.
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Page Intentionally Blank
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1. Executive Summary
Welcome to the Summary Report on the
Mid-Atlantic Integrated Assessment Estuaries
(MAIA-E). In this report we present a summation
of data collected in the environmental assessment
of mid-Atlantic estuaries conducted during the
summers of 1997-98. Over a dozen state and
federal environmental organizations participated
in the assessment and in the preparation of this
report. We hope this collaboration has helped
produce a summary that is relevant and useful.
The main objective of this report is to present
environmental data measured in the MAIA-E
program. We focus on several issues of wide-
spread interest: How prevalent is eutrophication
in mid-Atlantic estuaries? How contaminated are
the sediments? Are estuarine communities in the
sediments and water column disrupted by human
practices? Are the fish and shellfish we eat
contaminated?
The summary was written with three distinct
audiences in mind: (1) environmental managers
who are responsible for identifying and fixing
problems in estuaries; (2) concerned citizens
who are curious how estuaries operate and are
concerned how "their" estuary compares with
neighboring systems; and (3) researchers who
wish to know what type of data are available from
the MAIA program. Thus, a second objective of
the report is to present the MAIA assessment
information in a manner useful to all readers.
The mid-Atlantic estuaries fall naturally into
four geographical regions: the Delaware Estuary;
the Chesapeake Bay; the coastal bays in
Maryland and Virginia; and the Albemarle-
Pamlico Estuarine System (APES). In addition.
twelve smaller estuaries were monitored more
intensively to focus attention on a local scale.
Following are the main conclusions regarding
the environmental conditions in the mid-Atlantic
estuaries.
Eutrophication
There are ample signs of eutrophication in the
mid-Atlantic estuaries. In the region overall.
about 15-20% of estuarine area is affected by
high concentrations of nutrients, organic-rich
sediments, and oxygen-depleted waters. A third of
the estuarine area shows elevated concentrations
of chlorophyll a, and water visibility is less
than arm's length in half of the estuaries. These
symptoms of eutrophication vary widely among
estuaries.
In the Delaware Estuary, the urban Delaware,
Schuylkill, and Salem Rivers have high levels
of nutrients that are two to three times greater
than elsewhere in the mid-Atlantic region. High
levels of chlorophyll a are evident in parts of the
Delaware and Salem Rivers. But the pigment is
generally low in Schuylkill River and much of
Delaware Bay, perhaps because of limited light
availability. Oxygen depletion is not a major issue
in the Delaware Estuary.
In Chesapeake Bay, nutrient concentrations are
high in the Patuxent, Potomac, Severn, and South
Rivers. Most estuaries in Chesapeake Bay show
elevated levels of chlorophyll a, an indication
of extensive algal blooms. Chesapeake Bay
also displays the highest incidence of oxygen
depletion in the mid-Atlantic region — over half
of the area in the mainstem and Severn, South,
and Patuxent Rivers report oxygen values below 5
mg/L (in many places, below 2 mg/L).
Other eutrophication "hot spots" include
Sinepuxent Bay and parts of the Neuse River,
where elevated levels of nutrients and organic
matter are evident. The coastal bays are nutrient-
rich and especially turbid, but signs of organic
enrichment are generally absent. Otherwise,
estuarine systems with easy access to the sea, e.g.,
Delaware Bay, the lower Chesapeake mainstem,
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and open parts of Albemarle-Pamlico Sounds.
are relatively less affected by the symptoms of
eutrophication.
Sediment Contamination
Most of the mid-Atlantic estuaries have sediments
that are contaminated with metals and toxic
organic compounds. In the MAI A region overall.
30 to 40% of estuarine area exceeds effects range-
low (ERL) or effects range-median (ERM) limits
(ecologically-based guidelines) for metals and
organic toxicants.
The Delaware, Schuylkill, and Salem Rivers, the
upper Chesapeake mainstem, and the Severn
and South Rivers are especially polluted by
metals. Arsenic, nickel, mercury and zinc are the
metals most often exceeding ERL or ERM limits.
Mercury contamination is evident in Chowan
River and other parts of the APES.
Harmful concentrations of poly cyclic aromatic
hydrocarbons (PAHs), pesticides, DDT, and
polychlorinated biphenyls (PCBs) are present in
regions of the Delaware and Schuylkill Rivers,
the upper Chesapeake mainstem, and the Severn
and South Rivers. The organic toxicants are less
pervasive than metals throughout the region.
Only 1% of the region's sediments are
characterized as toxic, based on the survivability
of sediment organisms exposed to the sediments.
Toxicity is noted in the heavily contaminated
Delaware and Schuylkill Rivers, and in the
moderately polluted Chowan River. Other highly
contaminated systems, such as the Severn and
South Rivers are not characterized as toxic by this
test.
Condition of the Living
Resources
The MAIA program places particular emphasis
on the condition of communities in the water
and sediments — the living resources. A "benthic
community index", based on the diversity of
organisms and abundance of pollution tolerant
organisms in sediments, is used to evaluate
the condition of estuaries. The index rated
as "poor" several of the estuaries that also
show extensive signs of eutrophication and
sediment contamination, including Schuylkill,
Severn, South, and Potomac Rivers. But the
list also includes estuaries which show low or
moderate environmental degradation.
Over 3000 fish from 76 sites were examined for
signs of pathology. Only five abnormalities are
noted. However, when the edible portions of
fish and shellfish from the same sites were
analyzed for concentrations of metals and organic
toxicants, 65% of the tests revealed levels large
enough to present risk to human consumers.
Arsenic and PCBs were the only toxicants found
in harmful amounts.
Changes Over Time
The Environmental Monitoring and Assessment
Program (EMAP) conducted a similar
environmental study in the Virginian Province
(VP) in the summers of 1990-93. This study
region included part of the region surveyed by
the MAIA program in 1997-98. For estuaries
assessed in both the EMAP and MAIA studies,
it is therefore possible to look for changes
that occurred between 1990-93 and 1997-98. In
most cases, the uncertainty in the respective
measurements is too large to permit drawing clear
conclusions. However, the following conclusive
changes are evident:
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Organic contamination in the Delaware River
sediments worsened. The percentage of estuarine
area failing any organic ERM criteria increased
from 2 + 11% in 1990-93 to 34 + 10% in 1997.
It is not certain whether this increase represents
recent contamination or the dispersal of prior
contamination over additional area.
Metal contamination in the Chesapeake Bay
sediments worsened. The percentage of estuarine
area failing any ERM criteria increased from 5
± 3% in 1990-93 to 22 + 5% in 1997. Similar
changes occurred in the Chesapeake mainstem
and Potomac River.
The benthic community in the Chesapeake Bay
sediments showed increased degradation. The
percentage of estuarine area with a benthic index
< 0 (an indication of degradation) increased from
23 + 5% in 1990-93 to 37 + 5% in 1997.
Sediment toxicity diminished slightly in the
Chesapeake Bay. The percentage of estuarine area
failing the amphipod survival assay decreased
from 6 + 3% in 1990-93 to 0.3 + 0.3% in 1997.
Similar changes are noted in the Chesapeake
mainstem.
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2. Introduction
Humans have long appreciated the worth of
estuaries as sources of food and building
materials and as sites for manufacturing.
shipping, recreation, and tourism. But we now
worry that we may have disrupted the balance
of these sensitive ecosystems with our intensive
practices of industry, agriculture, recreation, and
urban development.
As a result of this concern, federal and state
environmental agencies have been directed to
evaluate the environmental condition of the
nation's estuaries. This summary report reviews
the results of an extensive study of estuaries in
the mid-Atlantic region of the United States in the
summers of 1997-98. The program is called the
Mid-Atlantic Integrated Assessment and focuses
on four adjacent estuaries: (1) the Delaware
Estuary, (2) the Chesapeake Bay, (3) the coastal
bays of Virginia and Maryland, and (4) the APES.
Many of the smaller estuaries that comprise these
systems are included in the study as well.
In this chapter, we highlight a few of the
most important features of estuaries in general,
and the mid-Atlantic estuaries in particular. The
chapter also introduces several of the most serious
problems that are evident in modern estuaries.
About Estuaries
An estuary is a semi-enclosed portion of the
sea that is diluted by freshwater. This definition
covers a wide variety of water bodies, including
bays, tributaries, inlets, sounds, lagoons, canals,
harbors, etc. All types are present in the mid-
Atlantic region. Most estuaries receive freshwater
from rivers. The mouths of these rivers are usually
brackish and influenced by tides; therefore, they
are considered to be estuaries as well. Many
coastal bays lack rivers, but are diluted instead by
fresh groundwater.
The larger systems in the region are good
examples of drowned-river estuaries that formed
thousands of years ago as the glaciers melted
and the sea level rose. Remnants of the former
drainage systems are still discernible as networks
of deep channels in the Chesapeake Bay and
Delaware Bay. The smaller coastal bays were
isolated from the sea when barrier islands formed
by processes that are still not well understood.
The mid-Atlantic bays are broad and shallow
well-mixed systems. Waves and tides keep the
waters relatively well-mixed vertically, except for
summers when distinct surface layers of warm,
buoyant freshwater may form. The turbulence, in
part, also accounts for the notoriously poor water
clarity in mid-Atlantic estuaries. It takes many
months for river water to flush the large estuaries.
Therefore, the estuaries are susceptible to the
effects of excessive quantities of nutrients and
toxic substances delivered by the rivers.
In some respects, estuaries are among the most
changeable environments on earth. Water depth
and clarity, salinity, sediment type, and many
other physical properties can vary widely over
short distances. Estuaries are also changeable
over time in response to the tides, the seasons,
and slower climatic changes. Such variability is
stressful. Yet remarkably, thousands of species of
estuarine organisms take advantage of the rich
niches provided by the changeable conditions.
Are the mid-Atlantic estuaries threatened?
Despite their adaptability and productivity, there
are clear signs of disruptive changes within the
estuaries. Most of the changes are traceable to
the increasing presence of humans. Population in
the mid-Atlantic estuarine watersheds has grown
from 13 million in 1950 to 21 million in 1990,
and is estimated to be 25 million by 2020. It is
unlikely that we can restrain human development
in estuaries. Therefore, the challenge is to
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understand how our presence affects estuarine
ecosystems and minimize disruptions where
possible.
Mid-Atlantic Estuaries
The mid-Atlantic region includes hundreds of
large and small estuaries. This report emphasizes
a few of the larger regional bays and tributaries
when reviewing results of the MAIA program.
In addition, a dozen smaller estuaries were
selected as "intensively-sampled systems" which
were sampled in higher spatial resolution both to
highlight conditions in smaller estuaries and to
evaluate variability in the measurements. Table
2-1 lists these regional and intensively-sampled
estuaries. See Figures 3-1 and 3-2 for station
locations.
• Chesapeake Bay is the largest estuary
in North America, home to more than 3,600
species of plants and animals and more than 15
million people. The bay is long and narrow, about
200 miles by 35 miles (320 by 55 km), and is
relatively shallow with an average depth of about
21 feet (6.5 m). Water quality issues have been a
primary concern in the Chesapeake Bay over the
past few decades. High nutrient concentrations
were blamed for increased incidences of algal
blooms, hypoxia, and loss of seagrasses. The bay
was the first estuary in the United States targeted
for intensive government-sponsored restoration
efforts, an effort formalized in the Chesapeake
Bay Agreement in 1983. There has been
noticeable improvement on all issues, but further
work is needed to meet restoration goals.
Other problems in the bay include chemical
contamination, air pollution, landscape changes,
depleted shellfish and fish stocks, and concern
about outbreaks of the toxin-producing organism
Pfiesteria.
Table 2-1. Mid-Atlantic Estuaries Highlighted in
the MAIA Program and This Report.
DELAWARE ESTUARY
Delaware River Schuylkill River*
Delaware Bay Salem River*
CHESAPEAKE BAY
Mainstem
Choptank River
Patuxent River
Potomac River
Rappahannock River
York River
James River
Cherrystone Inlet*
Severn River*
South River*
Eastern Bay*
Pocomoke River*
St. Jerome River*
Pamunkey River*
Mobjack Bay*
COASTAL BAYS
Chincoteague Bay
Sinepuxent Bay*
Virginia Coastal Bays*
ALBEMARLE-PAMLICO
ESTUARINE SYSTEM (APES)
Chowan River
Neuse River
* Intensively-sampled systems
• The Delaware Estuary includes the
Delaware Bay and Delaware River. The Delaware
Estuary is about a fifth the area of the Chesapeake
Bay, and is shallower, better mixed, and more
turbid. Although nutrient levels in water have
historically been high here, there are relatively
few signs of detrimental processes such as algal
blooms or severe oxygen depletion that often
accompany nutrient enrichment. In part, the
naturally turbid waters in the region may be
responsible for holding the growth of algae
in check. Seagrasses have apparently never
colonized the estuary in the past; therefore,
there is little concern regarding their present
absence. Recent concern is focused on sediments
contaminated with metals and organic com-
pounds, and the condition of shellfish, crab, and
fish populations.
• The coastal bays in this report refer
to representative coastal lagoons, small bays
and inlets situated along the Atlantic coast of
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Maryland and Virginia. There are no major urban
centers here, but the region is intensively farmed.
The bays have long flushing times, making them
susceptible to the accumulation of pollutants.
Boynton, et al. (1993) report that water quality in
the Maryland coastal bays is reasonably good in
the open waters of the Chincoteague and
Sinepuxent Bays, although more restricted parts
of the bays suffer algal blooms, low levels of
dissolved oxygen, and depleted benthic com-
munities (those living in the sediments). Limited
monitoring of sediments in the Maryland coastal
bays shows signs of toxic contaminants associated
with agricultural pesticide and herbicide use.
• The Albemarle-Pamlico Sound is the
second largest estuary in the United States.
Included in this estuary are the Albemarle and
Pamlico Sounds and the Chowan, Pamlico, and
Neuse rivers. The sounds are shallow basins,
separated from the sea by barrier islands. Rivers
here never drained extensive ice fields; thus
they lack a network of deep channels. Because
exchange with the sea is limited, the potential
effects of excess quantities of nutrients or other
pollutants are accentuated. Major concerns over
the past decade include increasing incidence of
algal blooms, sediments contaminated with toxic
materials (e.g., dioxin), and the severe depletion
of several species of finfish and shellfish.
• In addition to these large regional
estuarine systems, twelve smaller estuaries were
intensively sampled in space. These systems
include two tributaries of the Delaware River,
the heavily-developed Schuylkill River and the
Salem River; two threatened rivers in the upper
Chesapeake Bay, Severn River and South River;
and the Eastern Bay along the eastern upper
shore in Chesapeake Bay. Also included are
Pocomoke River, site of the harmful outbreak
ofPfiesteria during the summer of 1997 (the
outbreak curtailed the MAIA sampling effort
in the river); St. Jerome Creek, Mobjack Bay,
and Cherrystone Inlet in lower Chesapeake Bay.
Sinepuxent Bay to the north of Chincoteague Bay
and numerous sites in the Virginia coastal bays
were also measured intensively. Most of these
systems are influenced by urban or agricultural
development.
The MAIA Program
In 1995, the U.S. EPA Office of Research and
Development (ORD) formed a partnership with
the U.S. EPA Region 3 to implement a research,
monitoring, and assessment program in the mid-
Atlantic region. The intention of the program is to
perform an environmental assessment of several
key natural resources (lakes, streams, forests,
agricultural areas, wetlands, and estuaries) in
a single region. The study is called the Mid-
Atlantic Integrated Assessment and this report is
a summary of the estuarine component of the
MAIA program. The goals of the MAIA-E
program include providing the scientific know-
ledge needed to make sound environmental
decisions in the mid-Atlantic region and making a
well-documented and accessible data set available
to the public. The program is a partnership of
several federal, state, and local governments,
non-governmental organizations, and academic
institutions in the region.
In 1997, a coordinated monitoring effort was
initiated to respond to the information gaps
identified during the development of the
"Condition of the Mid-Atlantic Estuaries Report"
(USEPA 1998). More than 800 stations are
included in this current study, most of which
belong to the sampling networks of existing
monitoring programs in the region. The stations
meet the specifications of a probability-based
design which was developed by EPA's EMAP
(Weisberg, et al. 1993). In a probability-based
design, all locations in an estuary have equal
chance of being sampled, and the measured
results are weighted in proportion to the area
represented by the station. Estimates of condition
are, therefore, unbiased, and the uncertainty in
the estimates can be rigorously quantified. The
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MAIA-E program also incorporates the EMAP
approach of employing a consistent set of core
indicators in all estuarine assessments, a policy
that eases comparison with estuarine conditions
in other regions and highlights changes in mid-
Atlantic estuaries overtime. Biologically-based
indicators are particularly emphasized because
they provide a view of the overall condition of
the estuary.
During the summers of 1990-93, EMAP
conducted a survey of estuarine conditions of the
VP, which extends from Cape Cod through the
Chesapeake Bay (Paul, et al. 1999). The EMAP-
VP and MAIA-E programs overlapped in the
Delaware Bay and Chesapeake Bay. Sampling
and analysis methods were comparable for several
parameters in both programs. In this report, we
examine these two data sets for indications of
change from 1990-93 to 1997-98. Other studies
based on the EMAP approach were also recently
performed in the mid-Atlantic region, including
an assessment in the Carolinian Province (Cape
Henry, Virginia to Indian River Lagoon on the
east coast of Florida; Hyland, et al. 1998) and an
assessment of the Delaware and Maryland coastal
bays (Chaillou, et al. 1996). We do not look for
signs of change in these cases either because too
little time had elapsed between the studies or
there are an insufficient number of stations in
common in the respective programs.
A final goal of this cooperative research program
is to develop an integrated monitoring approach
that could be adopted in later monitoring efforts.
The MAIA-E program served as the model for
the Coastal 2000/National Coastal Assessment
program, which is presently implemented
nationally. The evolution of the monitoring
programs (from EMAP, through MAIA-E, to the
National Coastal Assessment) is discussed further
in Appendix I.
Report Organization
The remainder of the report is organized as
follows. Chapter 3 briefly discusses the sampling
design and location of stations employed in the
program. Chapters 4 through 6 present measured
values of thirteen parameters that describe the
chemical and biological condition of the estuaries.
The chapters are organized to emphasize the
issues of greatest concern in the region.
Chapter 4 - Eutrophication
Total Nitrogen in Surface Water
Total Phosphorus in Surface Water
Chlorophyll a in Surface Water
Total Organic Carbon in Sediments
Water Clarity (Secchi Depth)
Dissolved Oxygen in Bottom Water
Chapter 5 - Sediment Contamination
Metal Contamination in Sediments
Organic Contaminants in Sediments
Sediment Toxicity (Amphipod Survival)
Chapter 6 - Condition of Living Resources
Condition of Benthic Community
Number of Fish Species
Number of Fish Abnormalities
Contamination of Fish and Shellfish
Tissue
The measured data for each indicator are
displayed on maps, employing three categories to
show condition. In most cases, the categories are
defined in terms of well-established thresholds of
impairment, e.g., dissolved oxygen criteria used
by states to designate non-compliance. The three
categories are labeled "good," "fair," and "poor"
and colored green, yellow, and red as an aid to
interpreting the results. However, a few of the
indicators are still under development and lack
firm categories of condition. These categories are
colored and labeled more neutrally. The criteria
for these assessment categories are listed in Table
2-2.
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Table 2-2. Indicator Ranges Used to Define Assessment Categories.
Indicator Ranges
Eutrophication in Estuarine Waters
Rationale
Total Nitrogen (in surface water)
Low:TN < 0.5mgN/L
Intermediate: TN > 0.5 to 1.0 mg N/L
High:TN> 1.0mgN/L
The draft report of the Nutrient Criteria Technical Guidance Report:
Estuarine and Coastal Waters recommends using total nitrogen as
the measure of N-nutrient availability, but no specific categories of
impairment have yet been set (EPA 2001). The thresholds used to
define the map categories are the 25th and 75th percentile of all MAIA
TN values. The categories are useful when comparing conditions
among estuaries but are not unequivocal designations of degradation.
Total Phosphorus (in surface water)
Low: TP < 0.05 mg P/L
Intermediate: TP > 0.05 to 0.1 mg P/L
High: TP > 0.1 mg P/L
The Nutrient Criteria Guidance Manual also recommends using Total
Phosphorus as the best measure of P-nutrient levels in estuaries
(EPA 2001). In lieu of firm thresholds for map categories, this report
uses the 25th and 75!h percentile values of all data collected in the
MAIA program.
Chlorophyll a (in surface water)
Low: Chi a < 15ng/L
Intermediate: Chi a > 15 to 30 ug/L
High: Chi a >
15 ug/L is the SAV restoration goal in parts of Chesapeake Bay
(Batiuk et al. 2000). Both limits, 15 ug/L and 30 ug/L, have been used
in previous Mid-Atlantic assessments, e.g., Chaillou et al. 1996 and
Paul etal. 1998.
Total Organic Carbon in Sediments
Low:TOC < 1% dry weight
Intermediate: TOC > 1 to 3%
High: TOC > 3%
Analysis of TOC data collected in the EMAP-Virginian Province study
indicated that TOC values in the 1 to 3% range were associated with
impacted benthic communities, while values less than 1% were not
(Pauletal.1999).
Water Clarity (Secchi depth)
Clear: Secchi Depth > 1 m
Intermediate: Secchi Depth > 0.3 to 1 m
Turbid: Secchi Depth < 0.3 m
The 1 meter limit is equivalent to the SAV restoration goal in
Chesapeake Bay (Batiuk et al. 2000), and is comparable to the
"Bernie Fowler Sneaker Index", measured annually since 1988 by the
former Maryland State Senator. The limits 0.3 and 1.0 m have been
used consistently in previous mid-Atlantic assessments.
Dissolved Oxygen (in bottom water)
Low: DO < 2 mg/L
Intermediate: DO > 2 to 5 mg/L
High: DO > 5 mg/L
Prolonged exposure to oxygen concentrations less than 5 mg/L may
result in altered behavior, reduced growth, adverse reproductive
effects, and mortality (Vernberg 1972). Exposure to levels below 2
mg/L from 1 to 4 days causes mortality in most biota (Theede 1973;
Brongersma 1957). EPA's proposed salt water quality criteria cite DO
thresholds of 2.3 and 4.8 mg/L (EPA 2000). Most states have set their
water quality standard for DO at 5 mg/L.
Indicator Ranges
Chemical Contaminants in Sediments
Rationale
Metallic Contamination in Sediments
Low: No ERL Exceedances
Intermediate: Any ERL Exceedance
High: Any ERM Exceedance
ERL (effects range low) and ERM (effects range median) limits are
the concentrations of contaminants in sediments that will result in
ecological effects 10 and 50% of the time, respectively (Long et al.
1995).
Organic Contaminants in Sediments
Low: No ERL Exceedances
Intermediate: Any ERL Exceedance
High: Any ERM Exceedance
ERL (effects range low) and ERM (effects range median) limits are
the concentrations of contaminants in sediments that will result in
ecological effects 10 and 50% of the time, respectively (Long et al.
1995).
Sediment Toxicity (amphipod survival)
Low Tox: Survival > 80%
Intermediate: Survival > 60% to 80%
High Tox: Survival < 60%
The National Status and Trends and Environmental Mapping and
Assessment programs have been conducting surveys of sediment
toxicity throughout the US since 1981(Swartz et al. 1985; ASTM
1991), and have consistently used thresholds of 80 and 60% to
designate toxic and severely toxic conditions.
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Table 2-2 (con't). Indicator Ranges Used to Define Assessment Categories.
Biological Community Condition
Indicator and Threshold Values
Justification for Threshold Values
Benthic Community Index
Good Conditions: B.I. > 0
Poor Conditions: B.I. < 0
The Benthic Community Index uses discriminant analysis to
determine a weighted combination of parameters which distinguish
impacted and unimpacted sites in the EMAP-Virginian Province
(Paul et al. 1999). A comparable index developed for the Carolinian
Province was used to evaluate conditions in the Albemarle-Pamlico
Estuarine System. Zero by definition distinguishes good and poor
conditions.
Fish Diversity
Higher Diversity: > 3 Species
Lower Diversity: < 3 Species
Fish catch data are sensitive to methodological details; therefore,
no critical thresholds are used by assessment programs. In this
report, a threshold value of 3 species highlights the lowest third of
sites ranked by the number of fish species measured.
Fish Abnormalities
No Abnormalities
Abnormalities Present
The map categories highlight the absence or presence of
abnormalities.
Fish and Shellfish Tissue Contamination
No Exceedances
Any Exceedances
The number of exceedances is calculated using concentration
thresholds issued by the USEPA and American Fisheries Society
(EPA 2000).
Chapter 7 summarizes information regarding all
parameters in the form of a Report Card that
permits ready comparison of conditions across
regions. This chapter also compares the MAIA
results with the EMAP study conducted a few
years earlier in the mid-Atlantic region.
The references used in preparing this report are
listed in the References section, page 111. Ten
appendices contain information that supplements
the main chapters:
A - MAIA Estuaries sampling design
B - MAIA Estuaries methods and
indicators
C - Criteria for assessment categories
D - Values presented on maps
E - Percent estuarine area with
impairment
F - Statistical correlation coefficients
G - Selected MAIA and EMAP data
H - Index of Environmental Integrity
I - Recommendations for MAIA
monitoring
J - MAIA Estuaries Partners
All data measured in the MAIA Estuaries
program are available on the web at:
htto://www.epa.gov/emap/maia/html/data.html
10
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3. Methodology
Background
A number of federal and state agencies have been
involved in monitoring a variety of parameters in
the mid-Atlantic estuaries. From 1990 to 1993.
the U.S. EPA research initiative known as EMAP
was active in this geographic area. As data from
this effort were assessed, it became apparent
that small estuarine systems merited further
investigation. In order to facilitate this additional
research, partnerships were developed with other
agencies actively interested in estuarine science.
Many monitoring programs sponsored by federal
and state agencies are geographically based
within the mid-Atlantic region. The Chesapeake
Bay Program (CBP) in conjunction with the states
of Maryland and Virginia has been active in
monitoring the Bay since the program inception
in 1984. The Delaware River Basin Commission,
in cooperation with the states of Delaware,
New Jersey and Pennsylvania, has conducted
monitoring studies on the Delaware River and
Bay for a number of years. Individual states have
also designed and implemented complementary
monitoring programs. In the case of other federal
agencies, the National Park Service (NPS) has an
ongoing program to monitor in the Assateague
National Seashore, a large preserve on the
Delmarva peninsula. The National Oceanic
and Atmospheric Administration (NOAA) of
the U.S. Department of Commerce has been
active in monitoring both estuarine and marine
environments through the National Status and
Trends (NS&T) program and other initiatives.
In order to accomplish the MAIA Estuaries
project, partnerships have been forged among the
federal and state agencies listed in Table 3-1.
These partnerships recognize that each of the
governmental entities plays an important and vital
role in estuarine monitoring. Shared experiences,
data, and information contribute to the system-
wide approach that was implemented.
Table 3-1. Federal and State Partners in the
Monitoring of Mid-Atlantic Estuaries.
MAIA Partners
U.S. Environmental Protection Agency -
Offices of Research and Development, of Water,
and of Policy, Planning, and Evaluation; Regions
II, III, and IV
Chesapeake Bay Program
Department of Commerce - National Oceanic
and Atmospheric Administration
Department of the Interior - National Park
Service and U.S. Fish and Wildlife Service
States of Delaware, Maryland, North Carolina,
Virginia, New Jersey, and Pennsylvania
Delaware River Basin Commission
National Estuary Programs - Delaware Estuary
Program, Delaware Inland Bays Program,
Maryland Coastal Bays Program, Albemarle-
Pamlico National Estuary Program
Field Activities in 1997
and 1998
Over 700 sampling sites were visited during
the summer of 1997 to assess water and
sediment quality. These sites were selected using
statistical survey designs (random selection, refer
to Appendix A for details). Figure 3-1 presents the
geographic distribution of these sampling sites for
water and sediment quality. One of the objectives
of this project was to investigate small estuarine
systems; twelve of these systems were selected
for spatial intensification of sampling (Table 3-2).
These systems were selected both by random
selection and input from environmental managers.
11
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A OO s>
^O r°-a
'<^C°°o9
$
1997 Sampling Stations
0 Water Quality Only
° Sediment Quality Only
• Water and Sediment Quality
• •
0 itt
Figure 3-1. MAIA Stations Sampled During Summer 1997 in the MAIA Program.
12
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Approximately 110 sampling sites were visited
during the summer of 1998, with fish trawling
conducted at 80 sites. Figure 3-2 shows the
locations of the 1998 stations.
Table 3-2. Estuarine Systems Selected for Spatial
Intensification of Sampling.
Intensively Sampled Systems
Delaware Estuary:
Salem River
Schuylkill River
Delmarva Coastal Bays:
Sinepuxent Bay
Virginia Coastal Bays
Chesapeake Bay:
Severn River
South River
Pocomoke River
Mobjack Bay
Cherrystone Inlet
Saint Jerome Creek
Pamunkey River
Eastern Bay
# of sites
10
10
5
11
29
5
10
10
11
27
10
10
MAIA Indicators
A unique aspect of this collaborative project was
the sampling for a set of consistent measurements
across the mid-Atlantic estuaries by all of the
partners conducting the sampling and analysis.
The list of the parameters collected was developed
in conjunction with federal, state, and county
partners to address critical scientific issues
affecting these estuaries. These parameters focus
on many aspects of the estuarine biotic
community, both plants and animals, as well as
provide important information about the exposure
to stresses in the estuarine environment. In
general, the measurements include data on fish and
shellfish, benthic (bottom-dwelling) community
structure, water quality, toxic contaminants in
bottom sediment, and sediment toxicity. A
complete list of all parameters measured in the
MAIA program is included in Table 3-3.
13
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c
CO
O
o
o
o o
o
o
o S>
O
°
|p O^ oh°
*"" o
oo,
>2 c 8 o /o
o
o o
\ o°8°o
o
o
o
9°o ^
*
o
1998 Sampling Stations
\
° Fish and/or Crab
Figure 3-2. MAIA Stations Sampled During Summer 1998 in the MAIA Program.
14
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Table 3-3. Suite of Indicators Measured by Partners in MAIA Estuaries in 1997-98.
Location (latitude and longitude)
Time and Date of Sampling
Depth of Water Column
Water Column Measurements (Water Quality)
Physical measurements (surface and bottom; water column profiles at some stations)
Temperature Conductivity
Salinity Water Clarity (Secchi disk or turbidity)
Dissolved oxygen (measured once per station)
PH
Water Column Chemistry (surface and bottom)
Dissolved silica Dissolved orthophosphate
Dissolved ammonia Total particulate phosphorus
Dissolved nitrite and nitrate Particulate organic carbon
Dissolved nitrite Total suspended solids
Particulate organic nitrogen Chlorophyll a
Total dissolved nitrogen Pheaophytin
Total dissolved phosphorus
Sediment Measurements (Sediment Quality)
Benthic macroinvertebrates (1997 emphasis)
Species composition and enumeration
Bio mass
Silt-clay content (% silt/clay)
Observational SAV (in conjunction with benthic grab)
Sediment Chemistry (1997 emphasis)
NOAA NS&T contaminants (see table below)
Acid volatile sulfides (AVS) and simultaneously extractable metals (SEM)
Silt-clay content (% silt/clay)
Total organic carbon
Sediment Bioassay (1997 emphasis)
Pore water concentrations of ammonia and hydrogen sulfide
Microtox® sediment toxicity
Ampelisca abdita sediment toxicity
Fish/Shellfish Measurements (1998 emphasis)
Fish tissue contaminants
Fish community
External pathology
Macrophage aggregates
Crab hemolymph2+, Tributyltin, Tetrabutyltin
15
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Table 3-3 (con't). Suite of Indicators Measured by Partners in MAIA Estuaries in 1997-98.
Organic contaminants and major trace elements measured in sediments.
List is as used in NOAA NS&Tprogram (Valette-Silver 1992)
Polycyclic Aromatic Hydrocarbons
Low molecular weight PAHs
(2- and 3-ring structures)
1 -Methylnaphthalene
1 -Methylphenanthrene
2-Methylnaphthalene
2,6-Dimethyl naphthalene
1,6,7-Trimethylnaphthelene
Acenaphthene
Acenaphthylene
Anthracene
Biphenyl
Fluorene
Naphthalene
Phenanthrene
Chlorinated Pesticides
2,4'-DDD
2,4'-DDE
2,4'-DDT
4,4'-DDD
4,4'-DDE
4,4'-DDT
Aldrin
beta-Hexachlorohexane
Chlorpyrifos
cis-Chlordane
cis-Nonachlor
delta-Hexachlorohexane
Dieldrin
High molecular weight PAHs
(4-, 5-, and 6-rings)
Benzo[a]anthracene
Benzo[a]pyrene
Benzo[b]flouranthene
Benzo[e]pyrene
Benzo[ghi]perylene
Benzo[k]flouranthene
Chrysene
Dibenz[a,h]anthracene
Flouranthene
lndeno[1,2,3-cd]pyrene
Perylene
Pyrene
Endosulfan I
Endosulfan II
Endrin
alpha-Hexachlorohexane
gamma-Hexachlorohexane (lindane)
Heptachlor
Heptachlor epoxide
Hexachlorobenzene
Mi rex
Oxychlordane
trans-Chlordane
trans-Nonachlor
Polychlorinated Biphenyl congeners (UPAC numbering system)
PCB 8, PCB 18, PCB 28, PCB 44, PCB 52, PCB 66, PCB 101, PCB 105, PCB 118/1087
149, PCB 128, PCB 138, PCB 153, PCB 170, PCB 180, PCB 187/182/159, PCB 195,
PCB 206, PCB 209
Major and trace elements
Al, Si, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Sb, Ag, Cd, Hg, Tl, Pb
Organotins
Monobutyltin3+, Dibutyltin
16
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4. Eutrophication
Background
Estuaries are among the most productive
ecosystems on earth. They can produce organic
material at rates comparable to those in the most
intensively cultivated farm fields. Generally, high
productivity is a welcome attribute in ecosystems
because organisms can use the extra food to build
larger and more complex communities. It
is, therefore, ironic that some of the most
pressing problems in modern estuaries stem
from too much production, a condition called
eutrophication.
Eutrophication - an increase in the
rate of supply of organic matter to an
ecosystem.
-ScottNixon (1995)
The concise definition of eutrophication quoted
above is deceptively simple. It focuses on the
supply rate of organic matter to a water body.
In the case of estuaries, this usually refers to the
production of plant material via photosynthesis
by algae and macroalgae. The organic matter
may also originate externally, for example, from
pulp mills or sewage plants. Organic matter is
important because it is the food that supports all
other estuarine organisms.
The definition also stresses that eutrophication is
an increase in the supply rate of organic matter.
Eutrophication does not refer to estuaries that
are especially rich in nutrients or organic matter;
rather it pertains to systems that are in transition-
a system that is increasing its capacity to generate
organic material. If the transition is slow enough
that established communities can grow along
with the expanding food supply, the result
is a bigger, stronger ecosystem. Originally,
eutrophication was considered to be a beneficial
process. However, if eutrophication is too rapid,
the community of organisms cannot keep pace,
and excess organic material accumulates and
decays, creating serious problems throughout the
estuary.
Eutrophication can be attributed to many causes,
both natural or anthropogenic. For example,
organic production may increase in response to
a build up of nutrients in the watershed; eased
grazing pressure by herbivores; improved water
clarity (which can promote photosynthesis); a
diminished flushing rate; or an increase in
external sources of organic material in an estuary.
In recent decades, the dominant factor has been
an intensified supply of nutrients to estuaries, a
consequence of the accelerated development of
cities, farms, and industries in the watersheds
(National Research Council 2000).
The effect of the nutrient over-enrichment has
been largely detrimental. The excess nutrients
promote episodes of excessive growth of algae
in estuaries. The excess algae can form noxious
mats that choke beaches and hamper navigation.
As the uneaten organic material decays, it
depletes oxygen from water and sediments, most
persistently in the deep isolated trenches in
the region's estuaries, and more ephemerally
elsewhere in the water column. The excessive
amount of algal material (along with other
suspended material) also reduces water clarity,
thereby endangering the survival of the critical
seagrass habitat. Moreover, rampant algal blooms
are often dominated by a single species of non-
native algae. On rare occasions, the invading
algae may produce toxins that are harmful to
fish, shellfish, birds and mammals (including
humans). Perhaps the most familiar example
involves the organism Pfiesteria, which was
publicized in outbreaks in North Carolina and
Maryland.
17
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It is clear that eutrophication is a complex
process, with multiple factors influencing its
progress and a diverse array of possible
consequences, both beneficial and harmful. It
is easy to confuse the causes or effects
of eutrophication with the process itself. For
instance, an estuary is often considered to be
undergoing eutrophication if it is enriched in
nutrients or if it has suffered fish kills. It is helpful
to use the definition based on the supply rate of
organic matter, as was recommended by Nixon
(1995). We may then focus on conditions that
promote the excess production of organic matter,
and further focus on the harmful consequences of
the excessive quantities of organic matter. In this
way, we may better understand the processes that
govern eutrophication, and have a better chance of
controlling the adverse effects.
Eutrophication Indicators
Abroad suite of physical, chemical, and
biological parameters was measured during the
MAIA-E program. Six of these parameters
describe important aspects of eutrophication and
are used to assess conditions in the mid-Atlantic
estuaries. These "indicator parameters" are:
Total Nitrogen in surface water
Total Phosphorus in surface water
Chlorophyll a in surface water
Total Organic Carbon in sediments
Water Clarity (Secchi depth)
Dissolved Oxygen in bottom water
Total nitrogen and phosphorus are nutrients that
are likely causes of eutrophication. Chlorophyll
a and total organic carbon are measures of
the buildup of organic matter which defines
eutrophication. Diminished water clarity and
depleted oxygen supplies represent harmful
consequences of eutrophication. None are a
perfect indicator, but together they may identify
estuaries undergoing eutrophication.
Note on the
presentation of data
The measured data are displayed on maps,
using three categories to show condition.
When the categories are defined in terms
of well-established criteria, they are labeled
"good," "fair," and "poor" and the map symbols
are colored green, yellow, and red as an
aid to interpretation. In several cases the
categories are defined by criteria that are
still under evaluation; therefore, the maps are
colored and labeled more neutrally. Included
on each map is a graph that shows the
percentage of estuarine area that falls into
each condition category. A listing of these
estimates is included in Appendix E, and
measured values are displayed on plots in
Appendix D.
Total Nitrogen in Surface
Water
Estuarine plants need both nitrogen and
phosphorus nutrients provided roughly in a fixed
ratio in order to grow. Normally, there is plenty
of phosphorus in estuarine waters but relatively
little nitrogen. Nitrogen is, therefore, called
the "limiting" nutrient because algal growth
stops when nitrogen is depleted. When too
much nitrogen is available, the algae may
grow unchecked and cause harmful blooms.
Excess nitrogen also promotes the proliferation
of epiphytes (surface algae) to the detriment of
seagrasses.
The nitrogen cycle in estuaries is complex. There
are several types of nitrogen nutrients, each
serving a distinct function. Dissolved inorganic
nitrogen or DIN (e.g., nitrate, nitrite, and
ammonium) is preferred by plants but is usually
depleted by early summer. Dissolved organic and
18
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participate forms of nitrogen are released more
gradually during summer and are used by algae
to sustain plant blooms. Total nitrogen (TN) is
the combination of all organic and inorganic.
and dissolved and particulate forms of nitrogen
nutrients.
Ecologists have historically measured DIN in
estuarine assessments, largely because of the
difficulty of measuring other components reliably.
Thresholds indicating impairment are, therefore,
most often defined in terms of DIN. Federal and
state regulatory agencies now recommend using
TN as the best measure of year-round availability
of nitrogen nutrients (EPA 2001). Accordingly,
we use TN as the indicator of nutrient condition
in this summary. As yet, there are no firm criteria
for defining TN categories of impairment. We,
therefore, define three categories based on relative
values measured in the MAIA program.
Total Nitrogen - Surface Layer
Method: Total Nitrogen (TN) is calculated as
the sum of two parameters measured in the
MAIA program: the concentrations of total
dissolved nitrogen and particulate organic
nitrogen. This is equivalent to the sum of
all organic and inorganic, dissolved and
particulate forms of nitrogen. Water samples
were collected one meter below the surface.
Units: mg N/L; equivalent to ppm.
Assessment categories:
Low: < 0.5 mg N/L
Intermediate: > 0.5 to 1.0 mg N/L
High:> 1.0mgN/L
Range of data: 0.1 to 2.9 mg N/L
The thresholds used to define these
categories are the 25th and 75th percentile
of all MAIA TN values. While not definitive
indications of degradation, the categories
are useful when comparing the availability of
nutrients among neighboring estuaries.
Figures 4-1 and 4-2 are maps showing the
distributions of total nitrogen in the MAIA region
and in the intensively-sampled systems.
• Delaware Estuary exhibits the highest
concentrations of TN in the mid-Atlantic region.
Levels in the Delaware, Schuylkill, and Salem
Rivers are 3-4 times larger than are found
elsewhere (see Appendix D). Delaware Bay has
moderately high concentrations of TN.
• All tributaries in the Chesapeake
Bay show moderate to high concentrations
of TN, particularly at the mouths of the
Susquehanna, Patuxent and Potomac Rivers.
The upper Chesapeake mainstem is moderately
enriched, while its lower stretches are relatively
free of TN.
• All of the coastal bays are relatively
enriched in TN, especially Newport and
Sinepuxent Bays. Contamination by groundwater
draining from the surrounding farmlands and the
slow flushing rates in the bays are likely reasons
for high values.
• In the APES, only the well-flushed
Pamlico Sound shows low TN concentrations.
Otherwise, Chowan and Neuse Rivers exhibit
intermediate levels of nitrogen nutrients.
19
-------
o ®
°
o°0
°
o°o
Total Nitrogen in Surface Water
MAIA C
DELAWARE ESTUARY
Delaware Bay
Delaware River
CHESAPEAKE BAY
Mainstem
Choptank River
Patuxent River
Potomac River
Rappahannock River
York River
James River
COASTAL BAYS
Chincoteague Bay
ALBEMARLE PAMLICO
Chowan River
Neuse River
0 20 40 60 80 100
Percent Estuarine Area
O High:TN> l.OmgN/L
O Imermediate: TN > 0.5 to 1.0 mg N/L
• Low: TN < 0.5 mg N/L
50
Figure 4-1. Concentration of Total Nitrogen in Surface Water.
20
-------
o
i
Schuyikill River
o
o
+
On O
kilometers /-\
^2
5 6
Bay Pocomoke River
kilometers kilometers
0 ~2 0 4
kilometers
0 4
10
Cherrystone Inlet
11
Sinepuxent Bay
O
O
o
kilometers
kilometers
0 2
O,
O
4
kilometers
0 10
O High:TN>1.0mgN/L
O Intermediate: TN > 0.5 to 1.0 mg N/L
• Low: TN ^0.5 mg N/L
Total Nitrogen in Surface Water
Schuyikill River (1)
Salem River (2)
Severn River (3) I 1
South River (4) I I
Eastern Bay (5) I
Pocomoke River (6) L
St. Jerome Creek (?) I I
Pamunkey River (8) I I
Mobjack Bay (9) I
Cherrystone Inlet (10) I I
Sinepuxent Bay (11) I
VA Coastal Bays (12)
0 20 40 60 80 100
Percent Estuarine Area
Figure 4-2. Concentration of Total Nitrogen in Intensively-Sampled Systems.
21
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Total Phosphorus in
Surf ace Water
Phosphorus, like nitrogen, is an essential plant
nutrient. It is derived from natural mineral
deposits in the watershed and increasingly from
anthropogenic sources in the form of fertilizers,
sewage, detergents, and pharmaceuticals.
Phosphorus plays the role of the limiting nutrient
in freshwater environments, such as lakes and
streams and the fresher parts of estuaries. This
means that phosphorus rather than nitrogen
controls eutrophication in these regions. In fact, if
nitrogen becomes so abundant that it is no longer
the limiting nutrient in saltier waters, phosphorus
may become the controlling nutrient there as
well.
Phosphorus has several chemical forms and
participates in complex seasonal cycles. Recent
federal and state guidelines recommend using
total phosphorus (TP) as the best measure of
year-round availability of phosphorus nutrients in
estuaries (EPA 2001). As with nitrogen, there are
no well-established criteria that indicate "good"
or "poor" categories of TP enrichment. Therefore,
the upper and lower quartiles of all MAIA TP
measurements are used to characterize "high" and
"low" categories on maps.
Figure 4-3 and 4-4 present maps of total
phosphorus concentrations in the surface waters
of the MAIA region and intensively-sampled
systems, respectively. Generally, the distribution
of TP mirrors that of TN with a few exceptions.
• The highest concentrations of TP
are again evident in the Delaware, Schuylkill,
and Salem Rivers of the Delaware Estuary. The
Delaware Bay is also moderately enriched in TP.
• All tributaries in the Chesapeake Bay
are moderately to highly enriched, especially the
Patuxent, Potomac, Severn, and Salem Rivers.
The mainstem has relatively low levels of TP.
• The entire coastal bays, including
the Sinepuxent Bay, Chincoteague Bay and the
Virginia Coastal Bays are moderately enriched in
total phosphorus.
• In the APES, total phosphorus levels
are relatively high in the Chowan River and parts
of the Neuse River.
In summary, both nitrogen and phosphorus
nutrient levels are highest in the urban rivers
in the upper Delaware Estuary and western
Chesapeake tributaries, and in the agriculturally-
influenced coastal bays. We can compare these
nutrient-rich regions with the two following
indicators that reflect organic enrichment -
chlorophyll a and total organic carbon.
How do TN and TP compare with the more
conventional measures of the dissolved nutrient
classes, DIN and DIP (dissolved inorganic
phosphorus)? Maps of the region are qualitatively
similar regardless of the measure used. Generally,
TN and TP were about twice the DIN and DIP
values.
Total Phosphorus - Surface Layer
Method: Total phosphorus (TP) is calculated as
the sum of particulate and dissolved forms of
phosphorus: TP = total dissolved phosphorus
+ inorganic phosphate. Water samples were
collected from one meter below the surface.
Units: mg P/L; equivalent to ppm.
Assessment categories:
Low: < 0.05 mg P/L
Intermediate: > 0.05 to 0.1 mg P/L
High: > 0.1 mg P/L
Range of data: 0 to 0.34 mg P/L
The thresholds used to define these categories
are the 25th and 75th percentile of all MAIA TP
values measured.
22
-------
?
o,
o
o
o
V
o
o
CDD
O
•Q,
o
o
Total Phosphorus in Surface Water
MAIA
DELAWARE ESTUARY
Delaware Bay
Delaware River
CHESAPEAKE BAY
Mainstem
Choptank River
Patuxent River
Potomac River
Rap pa han nock River
York River
James River
COASTAL BAYS
Chincoteague Bay
ALBEMARLE PAMLICO
Chowan River
Neuse River
_LJ
I I I I I I
0 20 40 60 80 100
Percent Estuarine Area
O High: TP > 0.1 mg P/L
O Intermediate: TP > 0.05 to 0. L mg P/L
• Low: TP < 0.05 mg P/L
Figure 4-3. Concentration of Total Phosphorus in Surface Water.
23
-------
Salem River
4-
O
o
ooa
o^jb
•I
o
Severn River
South River
4
kilometers kilometers
0 ~~i 0 4
o
O
4
kilometers
j
item Bay Pocomoke River
O
O
O
St. Jerome Creek
o
8
Pamunkcy River
kilometers f~%
0—4
10
Cherrystone Inlet
o o o
kilometers kilometers
0 204
11
Sinepuxent Bay
O
O 12
VA Coastal Bays
O
O
o
o
O
4
O
o
4
0 4
O High: TP> 0.1 mgP/L
O Intermediate: TP > 0.05 to 0.1 mg P/L
• Low: TP < 0.05 mg P/L
kilometers Q
6 1
kilometers
0 2
o
kilojnsfers
0 10
Total Phosphorus in Surface Water
1012
Schuylkill River (1)
Salem River (2)
Severn River (3)
South River (4)
Eastern Bay (5)
Pocomoke River (6)
St. Jerome Creek (7)
Pamunkey River (8)
Mobjack Bay (9)
Cherrystone Inlet (10)
Sinepuxent Bay (11)
VA Coastal Bays (12)
I
J
J
kilometera
n 60
0 20 40 60 80 100
Percent Estuarine Area
Figure 4-4. Concentration of Total Phosphorus in Intensively-Sampled Systems.
24
-------
The categories used here to characterize nutrient
levels are relative. That is, nutrient levels are
considered to be high if they fell in the upper
quartile of MAIA measurements. A more definite
criteria of impairment would, of course, be
preferable. Defining such absolute criteria is a
high priority of estuarine research. However,
the definitions of high nutrient concentrations
used here (TN > 1 mg/L; TP > 0.1 mg/L) are
conservative compared with criteria used in other
assessments (Batiuk, et al. 2000, Bricker, et al.
1999). In other words, it is likely that conditions
labeled "high" in this report really do represent
concentrations that may adversely affect estuaries.
Chlorophyll a in
Surf ace Water
The key symptom of eutrophication is the
accumulation of organic material in an aquatic
environment. In most situations, this usually
refers to the accelerated production (i.e.,
photosynthesis) of algae in response to a rapid
increase in the supply rate of nutrients. Normally,
algae grow in "blooms" of limited extent and
duration (see text box). However, the natural
cycle can be disrupted if excessive quantities of
nutrients are available.
Chlorophyll a is the green pigment present in all
plants. The pigment is widely used as a surrogate
for algal biomass, which is otherwise difficult and
expensive to assess. High levels of chlorophyll
a are interpreted as the likely presence of
algal blooms. However, there is a drawback to
the methodology used to measure the pigment.
While phytoplankton is sampled representatively,
macroalgae is not. The method is likely to
underestimate the abundance of macroalgae.
In this report, we adopt the criteria used by
the Chesapeake Bay in their restoration program
for seagrasses and other submerged aquatic
vegetation (SAV). Pigment concentrations over 15
represent algal concentrations large enough
Algal Blooms
In healthy mid-Atlantic estuaries, algal
production follows a striking boom-bust
cycle in which algae "bloom" profusely for
a few days or weeks when nutrients are
available and other conditions are favorable.
Growth is checked when the limiting nutrient
is depleted. Herbivores graze the algae,
zooplankton eat the herbivores, other
consumers eat them, etc. The estuary is fed,
and the waters clear until the next bloom.
However, when nutrients are continuously
available, the algal blooms persist longer,
and more algae are produced than the
estuarine community can consume. The
extra organic material accumulates and
causes problems throughout the estuary.
The most common algae participating in
blooms are the microscopic forms called
phytoplankton. In shallower estuaries
where sunlight illuminates the sediments,
macroalgae (seaweeds) may dominate
bloom activity.
to shade and hinder growth of SAV (Batiuk,
et al. 2000). As there is no common criteria
designating bloom conditions, we consider
chlorophyll a concentrations greater than 30
Hg/L as "high," in general accordance with other
assessments in the region (Paul, et al. 1999).
Figures 4-5 and 4-6 show chlorophyll a levels
in surface water in the MAIA region and
intensively-sampled systems. About a third of
the region displays pigment levels that suggest
environmental impairment (concentrations
> 15 (ig/L; both yellow and red categories).
• The sub-systems of the Delaware
Estuary show a wide range of pigment
concentrations. Chlorophyll a levels are low in
the Delaware Bay, intermediate in the Delaware
River, and very high in the Salem River (over 80
[ig/L in parts - a likely indication of severe bloom
activity). Schuylkill River shows very low levels
25
-------
•+
kilometers
Chlorophyll a in Surface Water
MAIA I I I
DELAWARE ESTUARY 1C
Delaware Bay E
Delaware River LZ
CHESAPEAKE BAY I
Mainstem I
Choptank River I
Patuxenl River
Potomac River
Rappahannock River
York River
James River
COASTAL BAYS •
Chincoteague Bay I
ALBEMARLE PAMLICO C
Chowan River I
Neuse River C
i I
i
20
i
40
60
1
80
100
Percent Estuarine Area
• Poor: Chi > 30 jlg/L
0 Fair: Chi a >!5to30^g/L
• Good: Chi a <15|ig/L
SO
Figure 4-5. Concentration of Chlorophyll a in Surface Water.
26
-------
1
Schuylkill River
• 2
Salem River
Severn River
South River
V9
0%°
kilometers Q kijomet
kilometers kilometers
0 ~~2 0 4
Eastern Bay Pocomokc River
.
V •
St. Jerome Creek
Pamunkcy River
kilometers
0 4
0 4
10
Cherrystone Inlet
kilometers
0 ~~2 0 4
11
Sinepuxent Bay
• 12
VA Coastal Bays
O O
O °
v •
jL • • % * O
'T • •
. •
"f
kilometers
0~ ~~4
kilometers Q
6 i
kilometers
0 2
• Poor: Chi a > 30 wg/L
O Fair: Chi a > 15 to 30 «g/L
• Good: Chi a < 15wg/L
Chlorophylls in Surface Water
Schuylkill River (1)
Salem River (2)
Severn River (3)
South River (4)
Eastern Bay (5)
Pocomoke River (6)
St. Jerome Creek (7)
Pamunkey River (8)
Mobjack Bay (9)
Cherrystone Inlet (10) [
Sinepuxent Bay (11) L
VA Coastal Bays (12)
0 20 40 60 80 100
Percent Estuarine Area
Figure 4-6. Concentration of Chlorophyll a in Intensively-Sampled Systems.
27
-------
of chlorophyll a despite the very high TN and
TP levels measured there. It is likely that turbid
waters hinder algal productivity in this system.
• The western tributaries in the
Chesapeake Bay are consistently high in
chlorophyll a, with generally more than a quarter
of their estuarine area showing concentrations
greater than 30 ug/L. The entire mainstem is
relatively low in the pigment.
• Pigment levels in the coastal bays are
generally low despite a ready supply of nutrients.
Blooms of macroalgae are common in these
shallow systems but are not well-represented in
the chlorophyll a measurements. Turbid waters
may limit algal production in these bays as well.
• Much of the APES exhibit chlorophyll
a levels less than 15 ug/L, with higher values in
parts of the Neuse River and Albemarle Sound.
In short, chlorophyll a are high in the region.
But the most interesting observation concerns the
absence of high pigments in parts of the Delaware
Estuary and coastal bays, despite the very high
nutrient concentrations present. It is likely that
the naturally high turbidity in the estuaries in
the Delaware systems blocks the light available
to algae. That is, the algae are light limited
rather than nutrient limited, and, therefore, are
insensitive to nutrient concentration.
Blooms are very ephemeral events, and "snap-
shot" assessments, such as MAIAthat sample
estuaries once during the summer, cannot catch
all events. Thus, these measurements should be
viewed as minimum concentrations of chlorophyll
a.
Researchers often use statistical tests to look for
relationships among measured properties. Results
of such tests (see Appendix F) indicate that
chlorophyll a measurements correlate well with
TN and TP concentrations in the upper
Chesapeake Bay and coastal bays, but less so in
the nutrient-rich Delaware Estuary.
Chlorophyll a - Surface Layer
Method: Water samples are collected one
meter below the surface and analyzed by
fluorometer.
Units: ug/L; equivalent to ppb
Assessment categories:
Good: < 15 ug/L
Fair:> 15 to 30 ug/L
Poor: > 30 ug/L
Range of data: 0.7 to 95 ug/L
The lower threshold value of 15 ug/L is
equal to the restoration goals recommended
for the survival of SAV in Chesapeake Bay
(Batiuk, et al. 2000). The upper limit of 30
ug/L maintains continuity with an earlier
analysis in the region (Paul, et al. 2000) and
is typical of values used to represent bloom
conditions. Chlorophyll a is a measure of
the concentration of phytoplankton but not
macroalgae in the water column.
Total Organic Carbon in
Sediments
Total Organic Carbon (TOC) is a measure of
the concentration of organic matter in sediments.
It represents the long-term, average burial rate
of organic material in the sediments. High TOC
values are viewed as evidence of frequent algal
blooms in the overlying waters.
The rain of organic material to the sediments is
the primary source of food to the benthos. The
benthos is the community of worms, crustaceans,
shellfish, and other organisms living in or on the
estuary floor. Moderate fluxes of organic matter
are, therefore, beneficial, but larger loads may be
problematic if the benthic organisms are buried
or deprived of oxygen as the organic material
decomposes.
Figures 4-7 and 4-8 are the maps of TOC
concentration in sediments throughout the mid-
Atlantic region and the intensively-sampled
systems. The thresholds used to define condition
28
-------
categories are still under evaluation; therefore.
neutral colors are used on maps in this section.
• Within the Delaware Estuary, the
sediments of the Delaware River and the Salem
River are TOC-rich, while the Delaware Bay is
TOC-poor, roughly mirroring the distribution of
chlorophyll a in these systems. The mirror pattern
breaks down in the Schuylkill River where TOC
concentrations are very high, above 10% in spots,
despite low chlorophyll a values.
• In the Chesapeake Bay, the upper
mainstem has organic-rich sediments, while
those in the lower mainstem are relatively
carbon-free. The western tributaries and most of
the intensively-sampled systems are moderately
enriched. Severn River and South River have
some of the richest sediments in the region.
Total Organic Carbon in Sediments
Method: Sediments were acidified to remove
carbonate material, dried and combusted.
TOC is calculated as the percent carbon in dry
sediments.
Units: % carbon
Assessment categories:
Low: < 1 % carbon
Intermediate: > 1 to 3% carbon
High: > 3% carbon
Range of data: 0.02 to 13.7% carbon
The thresholds are based on an EMAP-VP
analysis which indicated that TOC values in the
1 to 3% range were associated with impacted
benthic communities, while values less
than 1% were not (Paul, et al. 1999). These
thresholds are still under evaluation.
Generally, these distributions do not mirror the
chlorophyll a measurements.
• Sediments in the coastal bays
have notably low concentrations of TOC.
Sinepuxent Bay and the Virginia coastal bays
have remarkably little buried carbon, on average
less than 0.3%.
• The APES has sediments rich in
TOC, especially in the Chowan and Neuse Rivers.
Pamlico Sound sediments are generally low in
organic carbon.
Water Clarity (Seechi Depth)
Estuaries are naturally murky places. Rarely can
an observer see more than two meters (about
6 feet) through the waters of mid-Atlantic
estuaries. Poor water clarity may be attributed
to a number of sources, including suspended
sediments, organic material (especially living
and dead algae), or dissolved tannins. The
turbid waters are beneficial because they provide
food and building materials used by estuarine
communities and can help small organisms hide
from predators, but the particles can be harmful
if they bury benthic communities or block light
from the threatened seagrass beds.
The MAIA program used a very simple and
effective method to measure water clarity. A white
Secchi disk is lowered through the water, and the
depth is noted when the disk becomes obscured
by suspended material. Shorter Secchi depths
indicate more turbid water. Waters with Secchi
depths more than a meter (3 feet) are considered
to be relatively clear, and turbid if visibility is
less than 0.3 meter (about a foot). This method
is similar to the "Bernie Fowler Sneaker Index,"
an informal survey conducted annually since 1988
by the former Maryland State Senator, who wades
into the water until he can no longer see his white
sneakers.
29
-------
?o
iO
*¥
o
o
o
o
y
°:oogj
o-
x.iv^jfy
• O o
o
o°o°
•
o
kilometers
Total Organic Carbon in Sediment
MAiA LI
DELAWARE ESTUARY
Delaware Bay
Delaware River [
CHESAPEAKE BAY I
Mainstem
Choptank River L"
Patuxent River L"
Potomac River C
Rappahannock River C
York River I
James River
COASTAL BAYS
Chirtcoteague Bay
ALBEMARLE PAMLICO
Chowan River [
Neuse River
0 20 40 60 80 100
Percent Estuarine Area
O High :TOC> 3% dry weight
O Intermediate: TOC > 1 to 3%
• Low: TOC < 1%
50
Figure 4-7. Concentration of Total Organic Carbon in Surface Water.
30
-------
o
o
o
r
°$
^
i
Schuylkill River
~f
kilometers
0
O
f>l
Tl
Oo
cP/
o
0 2
Salem
2 C
River
<
•f
kilometers k
0
2 0
Bay Pocomoke River
St. Jerome Creek
O
Pamunkey River
0 4
10
Cherrystone Inlet
+ .+.
kilometers kilometers
0 204
11
' o
Sinepuxent Bay
« 12
VA Coastal Bays
•+
o
'6
0°
O O O
O
O
O
o
V
^L^ *
kijometers
0 4
kilometers
0 1
+ .•
a
kilometers
0 2
kilometers
0 10
O High: TOC > 3% dry weight
O Intermediate: TOC > 1 to 3%
• Low:TOC
-------
Figures 4-9 and 4-10 show the patterns of water
clarity throughout the mid-Atlantic estuaries.
Overall the region is very murky, with only half
of the estuaries in the region having Secchi depths
more than a meter (i.e., visibility is limited to an
arm's length).
• In the Delaware Estuary, the Delaware
River and the Salem River are very turbid,
while the Delaware Bay and the Schuylkill River
are moderately turbid. These patterns do not
closely match the distribution of chlorophyll a,
suggesting that inorganic particles contribute to
the turbidity as well as algal material.
• In the Chesapeake Bay, many of the
western tributaries have visibility less than a
meter, while the mainstem is relatively clear.
• Visibility is limited to less than a meter
in all coastal bays. Chlorophyll a levels are low
in these systems, implying that inorganic particles
are the main cause of the turbidity.
• In the APES, about half of the
estuarine area has moderately-limited water
clarity (less than a meter). Again, resuspended
inorganic particles are the likely cause of the
turbidity.
Water Clarity (Secchi Depth)
Method: Secchi depth
Units: meters (m)
Assessment categories:
Clear: > 1 m
Intermediate: > 0.3 to 1 m
Turbid: < 0.3 m
Range of data: 0.1 to 5.0 m
A Secchi depth of 1 meter is comparable
to transmitting about 25% of ambient light
at one meter depth, which is equivalent to
the SAV restoration goals recommended for
Chesapeake Bay.
Water clarity (Secchi depth) depends on many
factors, both natural and anthropogenic. The fine
particles blocking light may be organic (algae
or their remnants) or inorganic (resuspended
sediments or soil washed from farm lands).
The poor correlation between visibility and
chlorophyll a levels — evident on the maps and
confirmed by statistical analysis (Appendix
F) — suggests the waters are turbid because of
sediment.
Dissolved Oxygen in
Bottom Water
All organisms in estuaries, barring anaerobic
microbes, need oxygen for survival. Normally,
the concentration of dissolved oxygen (DO)
in summertime estuarine waters is above 5
mg/L. When concentrations fall below 5 mg/L,
sensitive biota experience reduced reproduction
and growth. Many states use 5 mg/L as the criteria
designating unacceptable water quality. When DO
levels fall below 2 mg/L, the condition is called
hypoxia. Sensitive organisms can tolerate hypoxia
for only a few days before dying. The complete
absence of oxygen is called anoxia.
The concentration of DO in a parcel of water is a
dynamic balance between processes that provide
oxygen and those that remove it. Oxygen is
supplied by photosynthesis and transported from
the atmosphere. The main process depleting DO
from water is the respiration of biota, including
bacteria that decompose organic material in water
or sediments.
Oxygen depletion occurs naturally in mid-
Atlantic estuaries, especially during summer,
when respiration rates are highest, and in isolated
places where oxygen replenishment processes are
slow. A textbook example of a natural "dead
zone" develops each summer in the deep trenches
of the Chesapeake mainstem. The extent and
severity of the oxygen depletion have increased
in recent decades, in step with increased rates of
eutrophication.
32
-------
°
°
oo
o °
•
o
o
kilometers
Water Clarity (Secchi Depth)
MAIA
DELAWARE ESTUARY
Delaware Bay
i River
CHESAPEAKE BAY C
Mainstem C
Choptank River I
Patuxent River I
Potomac River [
Rappahannock River [
York River [
James River I
COASTAL BAYS
Chincoteague Bay C
1 1 1
1
1 1
1 1
1
1
1
1 1
1 1
1 1
• !
ALBEMARLE PAMLICO
Chowan River
Neuse River
0 20 40 60 80 100
Percent Estuarine Area
• Turbid: Secchi depth <0.3 m
O Intermediate: Secchi depth > 0.3 to 1 m
* Clear: Secchi depth > 1 m
Figure 4-9. Secchi Depths as a Measure of Water Clarity.
33
-------
o
Schuylkill River
Salem River
-o
'
Severn River
4
South River
O
kilometers
0 2
™
O
kilometers
6 2 6
5 6
Eastern Bay Pocomoke River
7
St. Jerome Creek
O
' +
kilometers
0 4
kilometers
(0 4
10
Cherrystone Inlet
300
Pamunlcey River
O
kilometers kilometers
0 ~~2 0 4
O
i!)
O
O
O
o
o
V
4
1 11
Sinepuxent Bay
O
O
O
. <
O 12
VA Coastal Bays
O
O
O
}
O
kilometers Q
O
8
O
0 2
0 10
• Turbid: Secchi depth < 0.3 m
O Intermediate: Secchi depth > 0.3 to 1 m
• Clear: Secchi depth > 1 m
Water Clarity (Secchi Depth)
Schuylkill River (1) C
Salem River (2) I
Severn River (3)
South River (4)
Eastern Bay (5)
Pocomoke River (6)
St. Jerome Creek (7)
Pamunkey River (8) I
Mobjack Bay (9) C
Cherrystone Inlet (10) C
Sinepuxent Bay (11) <-
VA Coastal Bays (12) £
Zl
Z!
H
J
0 60
0 20 40 60 80 100
Percent Estuarine Area
Figure 4-10. Secchi Depth (Water Clarity) in Intensively-Sampled Systems.
34
-------
Reduced oxygen levels may also occur for a few
hours during the night when the amount of
oxygen being consumed by biota temporarily
exceeds the amount being provided by
photosynthesis. The effects of short-term oxygen
stresses are poorly studied but probably adversely
affect organisms found throughout the water
column.
We report DO concentrations in bottom water
where the most severe cases of depletion
are generally found. The measurements were
conducted during daylight hours; therefore, they
do not accurately represent temporary changes
that occur during the night. The assessment
categories reflect the criterion used by states
in regulating water quality (< 5 mg/L) and the
conventional definition of hypoxia (< 2 mg/L).
Figures 4-11 and 4-12 show the distribution of
dissolved oxygen in bottom waters.
• Oxygen depletion is not a widespread
issue in the Delaware Estuary. Generally, DO
levels were above 5 mg/L, with a few incidents
of moderate and severe hypoxia evident in the
Delaware River, Schuylkill River, and Salem
River.
• The most severe cases of oxygen
depletion are restricted to the upper mainstem
and western tributaries in the Chesapeake Bay.
James River is relatively well-oxygenated. Of the
intensively-sampled systems, Severn River, South
River, and the Eastern Bays are notably depleted
in DO.
• Most of the waters in the coastal bays
are well oxygenated.
• The APES shows little sign of oxygen
depletion, except for moderate hypoxia noted in
parts of the Chowan River.
Dissolved Oxygen - Bottom Water
Method: Dissolved oxygen (DO)
concentrations in bottom water were
measured by an in situ oxygen electrode
method. The measurements were performed
during daylight hours, one meter above the
sediment surface.
Units: mg/L; equivalent to ppm.
Assessment categories:
Good: DO > 5 mg/L
Fair: DO > 2 to 5 mg/L
Poor: DO < 2 mg/L
Range of data: 0 to 11.7 mg/L
These measurements are likely to indicate
long-term episodes of oxygen depletion in
deeper water but are less likely to detect the
temporary overnight incidents of hypoxia that
may occur in productive surface waters.
As with most indicator parameters, the DO
record reflects both natural and anthropogenic
influences. The hypoxia and anoxia in the
Chesapeake Bay trenches are well known and
largely attributed to natural processes. The
trenches are isolated, stratified sites where
fine particles and organic matter accumulate--
all attributes that naturally promote oxygen
depletion. However, the extra organic loads
contributed by anthropogenic eutrophication
accentuate the problem as well.
The MAIA measurements capture persistent
events of depletion in deep water but miss the
short-term cases that may occur in surface water.
35
-------
••
Dissolved Oxygen in Bottom Water
MAIA
DELAWARE ESTUARY
Delaware Bay
Delaware River
CHESAPEAKE BAY I
Choptank River
Patuxent River
Potomac River
Rappahannock River
York River
James River
Chincoteague Bay
ALBEMARLE PAMLICO
Chowan River
Neuse River
0 20 40 60 80 100
Percent Estuarine Area
• Severe Hypoxia: DO < 2 mg/L
O Moderate Hypoxia: DO > 2 to 5 mg/L
• Good Conditions: DO > 5 mg/L
SO
Figure 4-11. Concentration of Dissolved Oxygen in Bottom Water.
36
-------
Schuylkill River
0
3
Severn River
kilonjeters
South River
kilometers
0 4
L.V
Pocomoke River
St. Jerome Creek
O
8
Pamunkey River
4-
kilunmers
0 4
kilometers
0 2
kilometers
0 4
10
Cherrystone Inlet
11
Sinepuxent Bay
.•
•'
:•
V
• 1.131
VA Coastal Bays
kilometers
0 4
kilomelera
0 1
0 2
kilometers
0 10
• Severe Hypoxia: DO < 2 mg/L
O Moderate Hypoxia: DO > 2 to 5 mg/L
• Good Conditions: DO > 5 mg/L
Dissolved Oxygen in Bottom Water
Schuylkill River (1)
Salem River (2) |
Severn River (3) I
South River (4) I I
Eastern Bay (5) I I I.'
Pocomoke River (6) [
St. Jerome Creek (7)
Pamunkey River (8)
Mobjack Bay (9)
Cherrystone Inlet (10)
Sinepuxent Bay (11)
VA Coastal Bays (12)
0 20 40 60 80 100
Percent Estuarine Area
Figure 4-12. Concentration of Dissolved Oxygen in Intensively-Sampled Systems.
37
-------
Summary: Eutrophication
Figure 4-13 presents a summary of the MAIA
eutrophication indicators reviewed in this chapter.
The vertical bars in the figure represent the
percent of estuarine area exhibiting impaired
(or excessive) conditions for each of the six
indicators. An ideal estuary, unaffected by
eutrophication, would display no bars. Estuaries
featuring many full bars are likely to be
experiencing eutrophication.
The first panel in Figure 4-13 summarizes
conditions in the entire MAIA region. The
percentage of estuarine area exhibiting potentially
harmful conditions are as follows (and are
reported in Appendix E):
Indicator
% Estuarine Area
in MAIA Region
Threshold
Total N
Total P
Chlorophyll a
TOC
Secchi depth
DO
21 ±12%
15 ±11%
32 ±10%
16 + 6%
50 ± 8%
21 ± 6%
> 1 mg N/L*
> 0.1 mg P/L*
> 15ug/L
> 3% carbon*
< 1 meter
< 5 mg/L
Threshold under review
These figures show that about 20% or less of the
MAIA region overall is affected by high nutrients,
carbon enriched sediments, or depleted DO levels.
About a third of the estuarine area has high
chlorophyll a concentrations, and a half has
visibility less than an arm's length. As was
pointed out in each subsection, these estimates
may be considered to be conservative or
minimum estimates.
These values agree well with other assays
conducted in mid-Atlantic estuaries. NOAA's
Estuarine Eutrophication Survey (Bricker, et al.
1999) queried experts from over 120 estuaries
in the continental United States. While using
different methods and measures, the NOAA
study found similar indications of eutrophication:
about a third of mid-Atlantic estuaries exhibited
moderate to high levels of chlorophyll a (> 15-20
Hg/L), and 10 to 20% of estuarine area showed
potentially harmful levels of nutrients and DO.
Comparable conditions were also measured in
USEPA's EMAP conducted in 1990-93 in parts
of the mid-Atlantic region (see Chapter 7 for a
comparison of EMAP and MAIA findings).
The following observations are evident in the sub-
regions and particular estuaries.
• In the Delaware Estuary, the relatively
fresh rivers show many signs of eutrophication.
The Delaware, Schuylkill, and Salem Rivers
all show widespread incidence of nutrient
enrichment and poor water clarity. Abundances of
chlorophyll a and TOC are high in some rivers
but more moderate in others where algal growth
may be limited by turbid conditions. In the turbid
Delaware Bay, while nutrient levels are high in
10 to 20% of the bay's area, along with elevated
chlorophyll a concentrations in about a quarter of
the bay, DO depletion is a minor concern in the
estuary.
• In the Chesapeake Bay, the mainstem
shows little sign of eutrophication, although DO
is depleted in 55 + 18% of the mainstem's area.
The Choptank, Patuxent, and Potomac Rivers
are generally nutrient-rich, high in chlorophyll a
(but low in sedimentary TOC), are turbid and
likely to suffer dissolved oxygen depletion. The
Rappahannock, York, and James Rivers have low
nutrient levels but are turbid and chlorophyll-rich.
• The intensively-sampled systems in the
Chesapeake Bay show a range of eutrophication
symptoms. In Severn River, South River, Eastern
Bay, and Pocomoke River, signs of eutrophication
are generally present in moderate to severe
proportions. St. Jerome Creek, Pamunkey River,
and Cherrystone Inlet have fewer signs of nutrient
excess, organic-rich sediments, or DO depletion
but are otherwise high in chlorophyll a and
turbidity. Mobjack Bay shows relatively few signs
of eutrophication.
38
-------
MAIA Region
100
75
« 50
25
™TP_
CHL
£
TOG
ECCHI
DO
n
MAIA
Delaware Estuary
100
75
50
25
DELAWARE Delaware Bay Delaware River Schuylklll River* Salem River*
ESTUARY
Chesapeake Bay and Tributaries
CHESAPEAKE Mainstem Choptank River Patuxent River Potomac River Rappahannock York River James River
BAY River
Chesapeake Bay: Intensively-Sampled Systems
Severn River* South River* Eastern Bay*
Pocomoke
River*
St. Jerome
Creek*
Pamunkey Mobjack Bay* Cherrystone
River* Inlet*
MD and VA Coastal Bays
= 100
»75
•g 50
3 25
1
nJ
COASTAL BAYS Chincoteague Sinepuxent Bay* VA Coastal Bays*
Bay
APES
ALBEMARLE- Chowan River Neuse River
PAMLICO
* Intensively-sampled systems
Legend. The six indicator parameters used to represent eutrophication along with the threshold indicating high
values or impaired conditions. Thresholds for TN, TP and TOC are not based on well-established criteria; therefore,
the bars above indicate "high" rather than "impaired" conditions.
I J I I I
Total Nitrogen Total Phosphorus chlorophyll a Total Organic
> 1 mg/L > 0.1 mg/L > 15u.g/L Carbon
CHL
TOC
SECCHI
DO
Secchi
Depth
< 1m
Dissolved
Oxygen
< 5 mg/L
Figure 4-13. Summary of Eutrophication Indicators. This graphic presents the "preponderance of
evidence" that an estuary is experiencing eutrophication. The vertical bars represent the percentage
of estuarine area exhibiting impaired conditions. Threshold values indicating impaired conditions are
listed in the legend.
39
-------
• The coastal bays are very turbid and
well oxygenated. The Virginia coastal bays are
largely symptom-free, while other bays exhibit
high levels of nutrients. Only the Sinepuxent Bay
shows signs of organic enrichment.
• In the turbid APES, nutrient levels are
relatively low, but there are indications of organic
enrichment in the sediments and water column,
especially in the Chowan and Neuse Rivers.
40
-------
5. Sediment Contamination
Background
Another issue of major environmental concern
is the pollution of estuarine sediments with
chemical contaminants. A wide variety of organic
compounds and metals are discharged into
estuaries from industrial, agricultural, and urban
sources. The contaminants are adsorbed onto
suspended particles and eventually settle to the
sediments. There they can exert toxic effects on
the benthic community that lives in the sediments
and can indirectly affect human health as well.
The MAIA program measured the concentrations
of 91 chemical constituents in sediments, as
well as their toxic effects of the sediments on
amphipods (crustaceans living in the sediments).
The results can be used to identify the most
polluted areas and give clues regarding the
sources of the contaminants. The data may also
aid in developing management plans that clean up
polluted sites.
The analytes measured include: 1) metals such as
arsenic, cadmium, lead, mercury and zinc,
which can be toxic in high enough levels; 2)
PAHs and aliphatic hydrocarbons, which are
petroleum residues and components produced by
combustion, as well as biogenic and naturally-
occurring substances; and 3) synthetic organic
chemicals, including PCBs used in insulators
and capacitors, pesticides, and organotins (a
component of anti-fouling paint).
Several factors strongly influence the extent
and severity of contamination by these toxic
compounds. Fine-grained sediments high in
organic matter are better able to adsorb the
pollutants than are coarser particles. The finer
particles are also more likely to be resuspended
by currents and transported to regions far from
their point of origin. For these reasons, silty
muds usually contain the highest concentrations
of contaminants.
In some cases, sediments may bind the toxicants
so strongly that they no longer pose a threat to
organisms. However, if organic-rich particles are
ingested or the chemicals are otherwise released,
the toxicants enter the food web. Shellfish, fish,
and other organisms tend to "bioaccumulate"
toxicants, threatening larger consumers, including
humans. Environmental managers are often
forced to curtail fishing and close shell-fisheries
in heavily-contaminated regions causing
significant economic expense.
In this chapter, we review the results of three
recognized measures of chemical contamination:
the concentrations of metallic and organic
toxicants in sediments and the toxicity of the
sediments toward an abundant and important
benthic organism.
Metal Contaminants in
Sediments
Metals are generally not harmful to organisms
at concentrations normally found in estuarine
sediments. Some, like zinc, are essential for
normal metabolism but are toxic above a critical
threshold. We use the approach of Long, et
al. (1995) to characterize contamination in
sediments. These researchers reviewed field and
laboratory studies and identified nine metals that
were observed to have ecological or biological
effects on organisms. They defined ERL values as
the lowest concentration of a metal that produced
adverse effects in 10% of the data reviewed.
Similarly, the ERM designates the level at which
half of the studies reported harmful effects. Metal
concentrations below the ERL value are not
expected to elicit adverse effects, while levels
above the ERM value are likely to be very toxic.
41
-------
Metal Contamination of Sediments
Method: Sediments were collected with a
modified Van Veen grab sampler, and the
top two cm were analyzed for chemical
constituents. The levels of nine metals are
compared to ERL and ERM limits, and a site
is assessed based on exceedances of these
limits.
Units: None are applicable.
Assessment categories:
Good: No ERL exceedances
Intermediate: Any ERL (but no ERM)
exceedance
Poor: Any ERM exceedance
This method of characterizing sediment toxicity
has been criticized because it does not evaluate
the interaction of multiple chemicals (complex
mixtures) nor does it account for the possible
mitigating effects of organic components in
sediments that may bind the metals and render
them harmless. Nevertheless, the method provides
a uniform perspective for evaluating contaminant
levels within and among estuaries.
Figures 5-1 and 5-2 depict concentrations of
metals in sediments expressed in relation to ERL
and ERM values. A station is rated "good" if the
concentrations of all nine metals are below the
ERL limit. An "intermediate" rating applies if any
metal exceeds an ERL limit, and a "poor" rating
signifies exceedance of an ERM limit for any
metal. Plots of the concentrations of the metals
are presented in Appendix D.
Overall, 31 + 7% of mid-Atlantic estuarine area
has sediments that exceed at least one ERL
limit. Arsenic and nickel are the most common
contaminants, present in about half of the sites
at levels greater than the ERL. Zinc, chromium,
mercury, and copper exceed the ERL in about a
quarter of the sites.
The estuaries most frequently exceeding an ERL
limit include the Delaware, Schuylkill, and Salem
Rivers; the upper Chesapeake mainstem; Severn
and South Rivers; and the upper Potomac River.
In addition, the Chowan and Neuse Rivers show
high levels of mercury.
Another 9 + 3% of the area exceeded an ERM
limit, usually because of nickel and/or zinc. These
more serious exceedances were most evident
in the Delaware, Schuylkill, South, and Severn
Rivers.
Over half of the Chesapeake Bay has metal
concentrations above the ERL limit, usually
for arsenic and nickel. Fifteen percent of the
region exceeds an ERM value, largely because
of high nickel levels. The heavily-urbanized
Severn, South, and Potomac Rivers and the upper
mainstem are notable for especially high levels
of nearly all metals in Table 5-1. Generally, the
northern bay and western tributaries are more
polluted than elsewhere in the estuary.
The sediments of the coastal bays include
generally low concentrations of metals. A few
stations in the Chincoteague Bay have arsenic and
zinc levels above the ERL limit. No sites exceed
an ERM limit.
Table 5-1. ERL and ERM Limits for Metals.
Metal Contaminants in Sediments
Metal ERL* ERM*
Arsenic (As)
Cadmium (Cd)
Chromium (Cr)
Copper (Cu)
Lead(Pb)
Mercury (Hg)
Nickel (Ni)
Silver (Ag)
Zinc (Zn)
8.2
1.2
81
34
47
0.15
21
1
150
70
9.6
370
270
220
0.71
52
3.7
410
* units are |ig/g dry sediment, equivalent to ppm
42
-------
•
.*.
o
Metal Contaminants in Sediment
MAIA L"
DELAWARE ESTUARY Q
Delaware Bay
i River
CHESAPEAKE BAY
Mainstem
Choptank River
Patuxent River
Rappahannock River
York River
James River
1
1
1
1
]
1
I ]
1 1
1 1
1 1
1 1
1 1
1
1
1 1
COASTAL BAYS L
Chincoteague Bay
ALBEMARLE PAMLICO L
Chowan River C
i River I
0 20 40 60 80 100
Percent Estuarine Area
kilometers
0 50
• Poor: Any ERM exceedance
O Intermediate: Any ERLexceedance
• Good: No ERL exceedances
Figure 5-1. ERL and ERM Exceedances for Metals in Sediments.
43
-------
Schuylkill River
O 2
„ Salem River
+
kilometers Q
0 2
0°,
0°
I
b°
kilometers kilometers
6 2 0 4
0
Astern Bay Pocomoke River St. Jerome Creek
8
Pamunkey River
kilometers
0 4
Mobjack Bay
10
Cherrystone Inlet
kilometers kilometers
0 204
11
Sinepuxent Bay
12
VA Coastal Bays
o o o
•+
o
o
o
o
o
V
•+
.•'
kilometers
0 4
kilometers •
ki
+ o.»
£
0 1
kil^msters
0 10
• Poor: Any ERM exceedance
O Intermediate: Any ERL exceedance
• Good: No ERL exceedances
Metal Contaminants in Sediment
Schuylkill River (1)
Salem River (2)
Severn River (3) [
South River (4) I
Eastern Bay (5) [
Pocomoke River (6) I 1
St. Jerome Creek (7) [
Pamunkey River (8) [
Mobjack Bay (9) [
Cherrystone Inlet (10) [
Sinepuxent Bay (11)
VA Coastal Bays (12)
0 6CI
0 20 40 60 80 100
Percent Estuarine Area
Figure 5-2. ERL and ERM Exceedances for Metals in Intensively-Sampled Systems.
44
-------
In the APES, about 20% of the estuarine area
exceeds an ERL limit (40 to 70% in the case of
the Chowan and Neuse Rivers). As in other mid-
Atlantic systems, arsenic and nickel levels are
high. The Chowan River and parts of Albemarle
Sound are notably high in mercury as well.
Organic Contaminants in
Sediments
We can perform the same ERL/ERM analysis to
characterize the levels of organic contaminants
in estuarine sediments. Table 5-2 lists 19 organic
analytes and associated ERL and ERM limits
as defined by Long, et al. 1995. Concentrations
of organic toxicants below the ERL value are
not expected to cause adverse ecological effects,
while concentrations above the ERM value are
likely to be very toxic.
Figures 5-3 and 5-4 show the condition of
sediments in the MAIA region and intensively-
sampled systems, expressed in terms of ERL
and ERM exceedances. On the maps, yellow
designates an exceedance of any ERL limit,
and red shows an exceedance of any ERM
limit. Appendix D includes plots that show
the concentrations of representative organic
compounds. This format highlights estuaries that
exhibit very high concentrations of toxicants.
In the MAIA region overall, 28 + 6% of the
estuarine area exceeds at least one ERL limit, and
only 1% exceeds an ERM value. The maps show
many stations that are designated "intermediate"
and colored yellow. In large part, this can be
attributed to total DDT levels, which narrowly
exceed the ERL limit at many stations. Below, we
highlight estuaries in which many toxicants are
present in high concentrations.
In the Delaware Estuary, the Delaware and
Schuylkill Rivers show very high levels of PAHs,
pesticides, and PCBs. The concentrations of
Table 5-2. ERL and ERM Values for Organics.
Organic Contaminants in Sediments
Analyte ERL* ERM*
Polycyclic Aromatic Hydrocarbons (PAHs)
Acenaphthene
Acenapthylene
Anthracene
Fluorene
2-Methyl Napthalene
Napthalene
Phenanthrene
Benz(a)anthracene
Benzo(a)pyrene
Chrysene
Dibenzo(a,h)anthracene
Fluoranthene
Pyrene
Low MW PAH
High MW PAH
Total PAH
Pesticides and PCBs
4,4'-DDE
Total DDT
Total PCBs
16
44
85
19
70
160
240
261
430
384
63
600
670
550
1700
4000
2.2
1.6
23
500
640
1100
540
670
2100
1500
1600
1600
2800
260
5100
2600
3160
9600
45000
27
46
180
* units are ng/g dry sediment, equivalent to ppb
pesticides 4,4'-DDE and DDT generally exceed
ERL limits in these rivers. The Delaware Bay and
Salem River are rated in "good" condition, except
for slightly elevated total DDT levels.
Most of the estuaries in the Chesapeake Bay
have concentrations of toxicants that are below
ERL limits, other than the mildly high DDT
levels. Exceptions include the upper mainstem, in
particular the Severn and South Rivers, where the
concentrations of all toxicants exceed ERL limits
by moderately large margins (see Appendix D).
45
-------
o
f
^*L Organic Contaminants in
<^ MAIA 1 1
0 ^ • 0/ DELAWARE ESTUARY II 1
9 |_ O** E Delaware Bay 1 1
• A DnlawarP! River 1 1
X-t, C^) - O * /* CHESAPEAKE BAY | 1
» ~'9- lf, n_ ^^ f Cg? Mainstem II 1
Sediment
•g.^ '* *0^ • 'jf Choptank River 1
* ^i • O Patuxenl Rivpr 1 1
^ • • • Potomac River | 1
*b "% Rappahannock River [^^^^^^B
•^ f!V York River ^^^^^^^H
OO o % 'i J James River | _B
9£bQ** m ^t
•'Ot! COASTAL BAYS 1 1
^T^1 , Chincoteague Bay •
•^ m Q
Al RPMARl E PAMlir.O 1 1
Chowan River 1 1
*CpW • Neuse River 1 I
1
1
i
i
i
i
i
i
^ ^ O o • 0 20 40 60 80 100
Q 0 Percent Estuarine Area
O
X« • Poor: Any ERM exceedance
d^jk V 1
r • Hr
3 Intermediate: Any ERL exceedance
kilometers * Good: No ERL exceedances
0 50
Figure 5-3. ERL and ERM Exceedances for Organic Compounds in Sediments.
46
-------
1
Schuylkill River
O
o
Salem River
+
kilometers
0 2
r
-------
The Maryland and Virginia coastal bays generally
have low levels of organic toxicants. Likewise.
there is no systematic evidence of wide-scale
contamination by organic toxicants in the APES.
Organic Contamination
in Sediments
Method: Sediments were collected with a
modified Van Veen grab sampler, and the
top two cm were analyzed for chemical
constituents. The levels of 19 organic
toxicants are compared to ERL and ERM
limits, and a site is assessed based on
exceedances of these limits.
Units: None are applicable.
Assessment categories:
Good: No ERL exceedances
Intermediate: Any ERL (but no ERM)
exceedance
Poor: Any ERM exceedance
Sediment Toxicity
(Amphipod Survival)
In addition to measuring the concentrations of
toxic chemicals in sediments, the MAIA program
performed several bioassay analyses in which
sensitive organisms were exposed directly to the
sediments. Here, we examine the results of the
static ten-day assay conducted using the
amphipod Ampelisca abdita (EPA 1994, 1995),
a common but ecologically important crustacean
that lives in estuarine sediments.
The bioassay is simple in concept. In the
laboratory, twenty juvenile amphipods are added
to the sediments from a site, and their survival
rate, relative to a control test, is calculated after
a ten-day exposure. The sediment condition is
classified as "good" (low toxicity) when survival
is greater than 80%, and "poor" (high toxicity) for
survival rates less than or equal to 60%.
Figures 5-5 and 5-6 show the results of the assay.
Sediments are not harmful to amphipods in 99%
of the mid-Atlantic estuaries.
The major exception to this observation occurs
in the Delaware Estuary, where parts of the
Delaware and Schuylkill Rivers exhibit some
amphipod survival rates below 25%, possibly in
response to the high levels of metals and organic
toxicants in the sediments of these rivers.
The relationship is not as simple in the
Chesapeake Bay. Sediment toxicity is evident in
the Pamunkey River and Cherrystone Inlet, which
are relatively uncontaminated with sediment
toxicants. Moreover, there is no sign of toxicity in
the sediments of Severn or South Rivers, despite
the presence of abundant contaminants.
There are no indications of sediment toxicity in
the coastal bays.
In the APES, the sediments of the Chowan
River appear to be highly toxic to amphipods.
These sediments are moderately contaminated
with mercury and nickel but less so than other
estuaries that passed the survival test.
Sediment Toxicity
Method: The top two centimeters of
sediment are reserved from samples
collected with a modified Van Veen grab
sampler. The survival rate of the amphipod
Ampelisca abdita is measured in the
laboratory following exposure to sediments
in a 10-day assay.
Units: Percent survival compared to a
control.
Map categories:
Low Toxicity: > 80% survival
Intermediate: > 60% to 80% survival
High Toxicity: < 60% survival
48
-------
Sediment Toxicity
(amphipod survival)
ESTUARY
Delaware Bay
Delaware River
CHESAPEAKE BAY
Choptank River j
Patuxent River |
Potomac River I
Rappahannock River I
COASTAL BAYS
Chincoteague Bay
ALBEMARLE PAMLICO
Chowan River
Neuse River
20 40 60 80 100
Percent Estuarine Area
• High Toxicity: Survival < 60%
O Intermediate Toxicity: Survival > 60% to 80%
• Low Toxicity: Survival > 80%
Figure 5-5. Survival Rate of Ampelisca abdita Exposed to Sediments.
49
-------
Astern Bay Pocomoke River
I
kilometers kilometers
204
10
Mobjack Bay Cherrystone Inlet
•
• High Toxicity: Survival < 60%
O Intermediate Toxicity: Survival > 60% to 80%
• Low Toxicity: Survival > 80%
Sediment Toxicity
(amphipod survival)
Schuylkill River (1) M
Salem River (2)
Severn River (3)
South River (4) |
Eastern Bay (5)
Pocomoke River (6)
St. Jerome Creek (7)
Parnunkey River (8) |
Mobjack Bay (9) |
Cherrystone Inlet (10) |
Sinepuxent Bay (11) |
VA Coastal Bays (12) |
0 60
0 20 40 60 80 100
Percent Estuarine Area
Figure 5-6. Survival Rate of Ampelisca abdita in Intensively-Sampled Systems.
50
-------
Summary:
Sediment Contamination
Figure 5-7 summarizes some of the major
findings of this chapter. Vertical bars in the figure
represent the area of an estuary displaying poor
conditions.
Most estuaries have sediments that are
contaminated with metals and toxic organic
compounds. In the MAIA region overall, 30 to
40% of the estuarine area exceeds at least one of
the ERL or ERM limits for metals and organic
toxicants. Only 1% of the region's sediments is
characterized as toxic, based on the amphipod
survival assay.
Arsenic and nickel are the metals most often
exceeding ERL or ERM limits in the region,
followed by mercury and zinc. The concentrations
of organic toxicants are highly correlated, that is,
when one compound is abundant at a site, it is
likely that other compounds are present as well.
Sediments in the Delaware, Schuylkill, and
Salem Rivers in the upper Delaware Estuary are
very heavily contaminated by both metals and
organic toxicants. These rivers exhibit the highest
concentrations of toxicants in the mid-Atlantic
region. Pollution by pesticides is common in these
systems. Large fractions of these sediments are
found to be toxic, as determined by an amphipod
survival bioassay.
Wide-spread sediment contamination is also
evident in the estuaries in the Chesapeake Bay.
Metals more than organics are likely to exceed
ERL or ERM levels in these systems. Patterns
of excessive contamination are most apparent in
the upper mainstem and in the Severn and South
Rivers, where concentrations of all metals and
organic toxicants are several times higher than
in neighboring systems. Remarkably, these highly
contaminated sediments show little indication of
being toxic.
About a third of the Chincoteague Bay exceeds
ERL limits for arsenic or nickel. Otherwise, the
Maryland and Virginia coastal bays generally
have low levels of metals and organic toxicants
and no indication of sediment toxicity.
The APES is moderately contaminated with
mercury, nickel, and pesticides. Much of the
Chowan River sediments are contaminated and
toxic.
Several general observations are evident from this
chapter. Contaminated sediments are common
in the mid-Atlantic estuaries. About a third of
the estuaries have concentrations of metals and
organic toxicants high enough to be harmful to
organisms.
A number of estuaries stand out because of
the extent and severity of contamination. These
include the Delaware River, Schuylkill River, and
Salem River in the Delaware Estuary; and the
upper mainstem and the Severn and South Rivers
in the Chesapeake Bay. All are situated near
urban centers, which are the likely sources of the
toxicants.
Only a small fraction of the region's sediments is
characterized as toxic, despite the high levels of
sediment contamination. Is the amphipod survival
assay an effective measure of sediment toxicity?
One plausible explanation for the poor correlation
is based on the observation that organic material
in sediments may bind toxicants so tightly that
they are unavailable to harm organisms. The
likelihood of this explanation is currently under
study.
51
-------
MAIA Region
£100
o 75
I 50
-
MET
ORG
MAIA
TOX
Delaware Estuary
2 100
o 75
I 50
1 25
W n
DELAWARE Delaware Bay Delaware River Schuylkill River* Salem River*
ESTUARY
Chesapeake Bay and Tributaries
100
75
50
25
fc
•JUiillll
CHESAPEAKE Mainstem Choptank River Patuxent River Potomac River Rappahannock York River James River
BAY River
Chesapeake Bay: Intensively-Sampled Systems
Severn River* South River* Eastern Bay* Pocomoke St. Jerome Pamunkey Mobjack Bay* Cherrystone
River* Creek* River* Inlet*
(% Estuarine Area
o 01 o 01 o
MD and VA Coastal Bays
I
COASTAL Chincoteague Sinepuxent VA Coastal
BAYS Bay Bay* Bays*
APES
ALBEMARLE- Chowan River Neuse River
PAMLICO
* Intensively-sampled systems
Legend. The indicator parameters used to characterize sediment conditions, along with threshold values
indicating impairment.
Metals in Sediment
Any ERL/ERM
Exceedances
Organics in Sediment
Any ERL/ERM
Exceedances
Sediment Toxicity
(Amphipod)
< 80% Survival
Figure 5-7. Summary of Sediment Contamination Indicators. Evidence that the sediment in an
estuary is contaminated and harmful to organisms. The vertical bars represent the percentage
of estuarine area exhibiting impaired conditions. Threshold values indicating impaired
conditions are listed in the legend.
52
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6. Condition of Living Resources
Background
In previous chapters, the assessment has
emphasized physical and chemical conditions in
the water and sediments. In this chapter, we look
to the organisms themselves for an indication
of the environmental condition of the estuaries.
Living resources (i.e., biological communities)
are ideal indicators, as they reflect long-term
conditions that are averaged over all seasons and
many annual cycles. The effects of exceptional
events, such as storms or droughts, are included in
the assessment as well. Importantly, all parties
in environmental actions (i.e., ecologists,
environmental as well as industrial managers,
regulators, etc.) tend to agree that the condition of
living resources is a fair judge of environmental
condition. For all these reasons, it is likely that
future environmental regulations will include
measurable biological indicators in addition to the
more familiar indicators of sediment and water
quality.
The worms, shellfish, and crustaceans that live
in or on the bottom surfaces of estuaries are
collectively called the benthos. They play a
central role in the estuarine food web and in
maintaining the quality of the water and
sediments in estuaries. Most healthy benthic
communities maintain an abundant and diverse
mix of native organisms. A shift away from
native species toward a more limited community
dominated by pollution-tolerant taxa is a likely
indication of an impaired ecosystem.
In this chapter, we review a benthic index which
reflects diversity in the benthic community and
the abundance of pollution-tolerant species.
We also examine two simple measures of fish
communities to gauge estuarine condition: the
number of fish species in an estuary, and the
incidence of abnormalities in fish. And finally,
because humans consume copious amounts of fish
and shellfish, we examine the residue of toxic
substances in the edible parts of fish and shellfish.
Condition of the Benthic
Community (Benthic Index)
Benthic communities are sensitive to many
environmental stresses such as salinity
fluctuations, oxygen deprivation, and poisoning
by toxic substances. Biologists often combine
several measures of stress into a single, easily
understandable index of community condition.
These measures are analogous to financial
indicators, such as the Dow Jones Index that
characterizes the condition of the economy.
Paul, et al. (1999) developed such an index to
evaluate the benthic condition of mid-Atlantic
estuaries. This index is based on a measure of
diversity and the abundance of pollution tolerant
taxa, and has been used to successfully identify
sites that are degraded throughout the region.
Figures 6-1 and 6-2 show the distribution of
benthic conditions throughout the region and
in intensively-sampled systems. Appendix D
displays the benthic index scores in comparison
with contaminant concentrations in sediments and
other parameters.
About 40% of the MAIA region has degraded
sediments as is reflected by benthic index scores
of zero or less. Index scores range from about
-9 to +4 in the mid-Atlantic region. Positive
values of the index signify healthy community
conditions, and negative values indicate degraded
communities.
About a third of the sediments in the Delaware
Bay and the Delaware, Schuylkill, and Salem
Rivers receives a poor rating by the benthic index.
53
-------
Benthic Community Condition
(Benthic Index)
MAIA I
DELAWARE ESTUARY
Delaware Bay |
Delaware River |
CHESAPEAKE BAY L
Mainstem |
Choptank River |
Patuxent River B
Potomac River |
Rappahannock River H
York River 1
James River |
ALBEMARLE PAMLICO £
Chowan River £
Neuse River £
_L
J
0 20 40 60 80 100
Percent Estuarine Area
Poor condition: B.I. <_Q
Good Condition: B.I. > 0
kilometers
50
Figure 6-1. Index of Benthic Community Condition (Benthic Index).
54
-------
5 6
stem Bay Pocomokc River
"
0 4
• Poor Condition: B.I. <0
• Good Condition: B.I. > 0
kilometers
0 2
kilometers
0 10
Benthic Community Condition
(Benthic Index)
2
Schuylkill River (1)
Salem River (2) |
Severn River (3) |
South River (4) |
Eastern Bay (5) |
Pocomoke River (6)
St. Jerome Creek (7) |
Pamunkey River (8) |
Mobjack Bay (9) |
Cherrystone Inlet (10) |
I I
Sinepuxent Bay (11) |
VA Coastal Bays (12) |
J
0 20 40 60 80 100
Percent Estuarine Area
Figure 6-2. Index of Benthic Community Condition in Intensively-Sampled Systems.
55
-------
The lowest scores in the mid-Atlantic region are
reported for the Schuylkill and Salem Rivers.
Overall, about a third of the Chesapeake Bay
is also rated as degraded by the benthic index.
Generally, the mainstem fares better than the
tributaries. Over half of Potomac and York
Rivers have negative indices. The Choptank and
Pamunkey Rivers are rated more positively.
The Maryland and Virginia coastal bays show the
best index scores in the study. Chincoteague and
Sinepuxent Bays and most of the Virginia coastal
bays merit positive scores.
Forty percent of the sediments in the APES has
degraded benthos. Forty to fifty percent of the
Neuse and Chowan Rivers is impaired.
When the benthic community index is compared
with other measures of water and sediment
quality, several statistically-valid relationships are
evident (see Appendix F). For instance, the
benthic index decreases in value as the DO
concentration decreases and as the degree
of sediment contamination increases. These
correlations demonstrate that the benthic index
responds to pollution gradients in the expected
manner and is a useful measure of benthic
condition.
Number of Fish Species
Ecologists tell us that diversity of fish communi-
ties is also an informative indicator of overall
conditions in an estuary. In the summer of 1998,
the MAIA program performed uniform fish trawls
in the Chesapeake Bay, Delaware Bay, and the
coastal bays.
The species count ranged from 0 to 13, with an
average of 4.6 species per site. The fish trawls
almost certainly underestimate the actual number
of fish species in an estuary because not all fish
habitats were sampled, and many fish can easily
Condition of Benthic Community
Method: A benthic index score was calculated
by an algorithm developed by Paul, et al.
(1999) in the EMAP-VP study to evaluate
the condition of benthic communities in mid-
Atlantic estuaries. This index is based on
a measure of diversity and the abundance
of pollution tolerant taxa (see Appendix B).
Positive values signify healthy community
conditions, and negative values indicate
degraded communities.
Units: The index has no units
Assessment categories:
Good: > zero
Poor: < zero
Range of data: -8.9 to 4.1
A benthic index for the Albemarle-Pamlico
Estuarine System is calculated using a
separate algorithm developed for that region
(Jeff Hyland, personal communication). Those
data are categorized as good or poor,
equivalently to EMAP-VP index. Also, a slight
adjustment to the scores of the Delaware
Estuary is made (+ 0.3 added) to account for
a difference in analysis methods used for that
system. See Appendix B for details.
avoid the trawl nets. Still, the estimates provide
a comparison of the relative fish diversity among
estuaries.
Figure 6-3 indicates the results of the fish species
count. The following ranges were observed:
System
Number
Delaware Estuary 5-6
Sinepuxent Bay 4-8
Chincoteague Bay 2-6
VA coastal bays 3-13
Upper Chesapeake Bay 5-6
Severn & South Rivers 0-3
Patuxent River 2-5
Potomac River 0-7
Rappahannock River 1 -5
York River 4-8
James River 3-9
56
-------
Relatively more fish species were found in the
upper Delaware Bay, the coastal bays, and in the
upper portions of tributaries. Fewer species were
evident in the Chesapeake mainstem and lower
tributaries.
Number of Fish Species
Method: Standard trawls were conducted: 10
± 2 minutes in duration with a towing speed
of 2-3 knots through the water against the
prevailing current. Fish were identified in the
field.
Units: This parameter has no units.
Map categories:
Low: Zero to three species
High: More than three species
Fish Abnormalities
As an additional check on the health of the
fish community, fish caught in the trawls were
examined for external abnormalities (ulcers,
growths, and abnormal backbones). The site was
designated "poor" if any abnormality was found
in any fish. Figure 6-4 shows the incidence of
abnormalities in the Chesapeake and Delaware
estuaries.
The overall incidence of abnormalities was low.
The only pathologies found were ulcers on five
fish, a rate of less than two abnormalities per
thousand fish. These results are comparable to the
rate of abnormalities observed in the 1990-1993
EMAP-VP study, in which the incidence was less
than three abnormalities per thousand fish.
Fish Abnormalities
Method: 3286 fish from 76 trawls were
examined in the field for signs of external
pathology (lumps, growths, ulcers, orfinrot).
Diagnoses of pathology were confirmed by
expert pathologists.
Units: This parameter has no units.
Map categories:
Low: No abnormalities
High: One or more abnormalities
Contamination of Fish and
Shellfish Tissue
In estuaries with contaminated sediments, there is
additional concern that the metallic and organic
pollutants may be concentrated in secondary and
tertiary consumers such as shellfish and fish.
Such bioaccumulation arises because the predator
retains most of the contaminants from the prey
organism. These contaminants are stored in the
edible tissue of the fish and shellfish, and,
therefore, pose a risk to humans who consume the
contaminated organisms.
In the MAIA study, representative samples of
edible tissue from summer flounder and blue
crabs were analyzed for metallic and organic
toxicants. Table 6-1 lists the analytes and
concentration limits considered by USEPA to
present risks to human consumers (USEPA
2000c). The limits are based on human health
risk assessment and are considered to be
protective of recreational, tribal, ethnic, and
subsistence fishers who are likely to consume
more fish than the general population.
57
-------
.4*
* '
9
vv
Mpa!
o o
o
f
•^>
^
3-^
5 °
i. o-
• *
«
ChO
-% o
9
Number of Fish Species
O Low Diversity: < 3 species
• High Diversity: > 3 species
O
kilometers
40
Figure 6-3. Number of Fish Species.
58
-------
.
Fish Abnormalities
• Abnormality Present
• No Abnormality
^Cr
kilometers
40
Figure 6-4. Occurrence of Abnormalities in Fish.
59
-------
Only a limited number of sites in the Chesapeake
Bay, Delaware Bay, and the coastal bays were
investigated for tissue contamination. Figure 6-5
shows that most fish sampled had at least
one exceedance to the consumption guidelines.
Thirty stations (65% of all stations) are out of
compliance. Of these, 23 exceed the arsenic limit,
with an average tissue concentration of 2.5 ppm
(and a maximum of 4.9 ppm). Thirteen of the
stations exceed the PCB limit, with an average
concentration of 40 ppm (and maximum of 81
ppm). No other analyte is responsible for an
exceedance in this limited study.
Table 6-1. USEPA Chemical Analytes and
Consumption Limits Used in Issuing Fish
Advisories.
Fish/Shellfish Tissue Contaminants
Analyte
Arsenic
Cadmium
Mercury
Selenium
Chloropyrifos
Dieldrin
Endosulfan
Endrin
Heptachlor epoxide
Hexachlorobenzene
Lindane
Total Chlordane
Total DDT
Total PAH
Total PCB
limit (ppm)
1.2
4
0.4
20
123000
2.5
24000
1200
4
25
30
110
120
6
20
Contamination in Fish and
Shellfish Tissue
Method: Edible portions of summer flounder
or blue crab were composited,
homogenized, and analyzed for
concentrations of metals and organic
compounds. The concentrations of analytes
were compared to consumption limits for
fish, as recommended by USEPA (2000).
The condition at a site was determined by
the number of exceedances.
Units: None are applicable.
Map categories:
Low: No exceedances
High: > 1 exceedance
Summary: Conditions of the
Living Resources
38 + 8% of the mid-Atlantic estuaries overall
have benthic communities that are degraded, as is
indicated by the benthic community index.
The benthic communities in the poorest condition
are located in the Delaware, Schuylkill, and
Salem Rivers, and in the Potomac, South, and
Severn Rivers. These systems show extensive
signs of eutrophication and/or sediment
contamination. However, the benthic community
index also indicated extensive poor conditions in
a number of systems that were not otherwise
afflicted with environmental problems. These
include the York and Neuse Rivers and the St.
Jerome Creek and Cherrystone Inlet.
Over 3,000 fish were examined for signs of
external pathology. Less than two abnormalities
per thousand fish were noted — a positive
indication of condition.
In 65% of the analyses performed, the edible
portions of fish and shellfish contained metals
and/or organic toxicants at levels large enough
to present risk to human consumers. Arsenic and
PCBs were the only toxicants that exceeded EPA
guidelines.
60
-------
Contamination of Fish and
Shellfish Tissue
Any exceedance
No exceedances
Figure 6-5. Contaminant Exceedances in Fish and Shellfish Tissue.
61
-------
7. Summary of Conditions
Conducting an environmental assessment of
estuaries is far from a precise exercise. In a
large part, this reflects the complexity of estuarine
processes and the experimental nature of the
assessment procedure itself. As we have tried
to emphasize, no assessment indicator is perfect.
And the "snap-shot" nature of the MAIA
sampling strategy limits the interpretation of
some results. Still, valuable insights are available
from an unbiased, concurrent view of conditions
in neighboring but diverse estuaries.
In past chapters, we have used a variety of
methods to summarize estuarine conditions. Maps
offer a visual comparison, and associated charts
provide quantitative estimates of the extent of
impairment and distribution. Also, summaries
based on a "preponderance of evidence" (Figures
4-13 and 5-7) provide appraisals that compensate
in part for the limitations of individual indicators.
In this chapter, we offer an additional summary
of overall conditions: a report card based on
the extent of environmental impairment. Finally,
we review how conditions in the mid-Atlantic
estuaries have changed since the 1990-1993
EMAP study was conducted in the region.
Environmental Report Card
Figure 7-1 is an environmental report card for the
mid-Atlantic estuaries based upon the percentage
of estuarine area showing impaired conditions.
The criteria for impairment are listed near the
bottom of the report card (and are the same
thresholds used throughout the report). A red-
yellow-green color scheme is used to indicate
conditions for those indicators with well-
established criteria for impairment. Neutral colors
are employed to designate conditions in cases
for which the assessment criteria are still
under evaluation (i.e., for total nitrogen, total
phosphorus, and total organic carbon in
sediments).
In the report card, conditions are considered to be
good (or better) if less than 20% of the estuarine
area exhibits impairment, colored green or blue.
Yellow indicates that 20 to 40% of the estuarine
area is impaired, and red and orange are used
to designate poorer conditions in which more
than 40% of the estuarine area fails the indicated
impairment guidelines. A version of this report
card complete with estimates of impaired areas is
included in Appendix H.
A glance at the report card reveals that high-
nutrient conditions are prevalent in the Delaware
Estuary tributaries, in several Chesapeake Bay
tributaries, as well as in the coastal bays.
Carbon-rich sediments are common in the
Delaware Estuary and the APES. Chlorophyll a
concentrations (a sign of excessive algal biomass)
and poor water clarity are common in most
estuaries. Depleted levels of DO are largely
restricted to the mainstem and adjacent sections
of the Chesapeake Bay tributaries. In short, ample
signs of eutrophication are evident throughout the
mid-Atlantic region.
The report card further indicates that contamina-
tion of sediments by metals and organic toxicants
is commonplace throughout the region, except
for the Delaware Bay and parts of the coastal
bays. Metals exceed the impairment criteria more
often than organics. There is little indication of
sediment toxicity (as measured by the amphipod
survival assay).
The benthic community index, a measure of the
diversity and health of the estuarine sediment
community, indicates that nearly all of the region
exhibits moderate to extensive impairment. In
63
-------
Eutrophication
Sediment
Contamination
Benthic
Community
Tot Org „ Water Diss
Carbon ^Clarity Oxygen
Sediment Benthic
Me la Is Orqanics .
Toxicity Index
I n
DELAWARE ESTUARY
Delaware Bay
Delaware River
Schuylkill River*
Salem River*
CHESAPEAKE BAY
Mainstem
Choptank River
Patuxent River
Potomac River
Rappahannock River
York River
James River
Severn River*
South River*
Eastern Bay*
Pocomoke River*
St. Jerome Creek*
Pamunkey River*
Mobjack Bay*
Cherrystone Inlet*
COASTAL BAYS
Chincoteague Bay
Sinepuxent Bay*
VA Coastal Bays*
ALBEMARLE-PAMLICO
Chowan River
Neuse River
Intensively-sampled systems
Better conditions
Worse conditions
Less than 20% of estuarine area exhibits high values or impairment
20% to 40% of area exhibits high values or impairment
More than 40% of area exhibits high values or impairment
Note regarding color schemes: The thresholds used to define assessment categories for TN, TP, and TOC are
developmental and are under evaluation. Neutral colors are used to characterize these indicators, and interpretation as "high"
or "low" may be more appropriate than "good" or "poor". Categories for other indicators are based on established criteria and
may be interpreted as "impaired" or "unimpaired".
Figure 7-1. Environmental Report Card for mid-Atlantic estuaries based on the percentage of
estuarine area that exceeds the designated impairment threshold. Warm colors (red or orange)
indicate a greater incidence of impaired conditions or excessively high concentrations of a
substance.
64
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some estuaries, e.g., the Schuylkill, Patuxent,
Potomac, South, and Severn Rivers, the low index
rating coincides with extensive signs of eutrophi-
cation and sediment contamination. However, low
ratings are also evident for estuaries with low or
moderate levels of degradation, e.g., York River,
St. Jerome Creek, and Cherrystone Inlet.
Change in Conditions:
1990-93 to 1997
The EMAP conducted an environmental assess-
ment of estuaries along parts of the Atlantic
seaboard during the summers of 1990-93. We
may, therefore, look for changes that occurred
over time at locations included in both programs
and for parameters measured by comparable
methods.
The EMAP-VP and MAIA-E programs
overlapped only in parts of the Chesapeake Bay
and the Delaware Estuary. Estuaries in common
included the Delaware River and the Delaware
Bay in the Delaware Estuary, and the Chesapeake
mainstem, and the Potomac, Rappahannock, and
James Rivers in the Chesapeake Bay. Analyses
performed by comparable methods in both studies
included DO in bottom water, exceedance of
ERM limits in sediments for metals and organic
toxicants, sediment toxicity (amphipod survival),
and benthic community condition (benthic index).
Both programs used the same probability-based
sampling strategy and weighted the results in
proportion to the area represented by the station.
This permits the appraisals of the condition to
be expressed with estimates of reliability (95%
confidence intervals). Only changes greater than
the combined uncertainties were considered to be
statistically robust.
Figure 7-2 illustrates the changes that occurred
from 1990-93 to 1997. There was considerable
degradation of the Delaware River sediments
by organic contaminants over this time period.
More than a third of the estuarine area was
contaminated in 1997, a large increase above
the 1990-93 estimate. One possible explanation
that bears further examination postulates that
these findings reflect the dispersal of highly-
contaminated sediments throughout a larger
fraction of the river over time.
Similarly, a larger portion of sediments in
the Chesapeake Bay (particularly the mainstem
and Potomac River) showed increased metal
contamination in the sediments.
The condition of the benthic community in
the Chesapeake Bay worsened, as is indicated
by the benthic community index. A moderately
greater percentage of the Bay showed diminished
diversity in the composition of the community.
Sediment toxicity, as measured by the amphipod
survival assay, decreased slightly in the
Chesapeake Bay overall and in the Chesapeake
mainstem.
65
-------
Changes in Environmental Conditions in the
Delaware Estuary and Chesapeake Bay
1990-93 to 1997
Delaware Estuary
Worse Better
Chesapeake Bay
Worse Better
Organic contaminants in the
Delaware River sediments get worse.
% area failing any ERM criteria
1990-93: 2+11%
1997: 34 + 10%
Benthic community in the
Chesapeake Bay gets worse.
% area with benthic index < 0
1990-93: 23 + 5%
1997: 37 + 5%
Metal contaminants in the
Chesapeake Bay sediments get worse.
% area failing any ERM criteria
1990-93: 5 + 3%
1997: 22 + 5%
Similar changes occurred in the mainstem
and Potomac River.
Sediment toxicity decreases
S in the Chesapeake Bay.
% area failing toxicity assay
1990-93: 6 + 3%
1997: 0.3 + 0.3%
Similar changes were noted in the
Chesapeake mainstem.
Figure 7-2. Changes in Environmental Conditions: 1990-93 to 1997. Arrows show changes in
environmental conditions evident between the 1990-93 EMAP and 1997 MAIA studies. Comparisons
are performed for locations and parameters common to both studies. Values reported are the percent
of the estuarine areas displaying degraded condition + 95% confidence intervals.
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Appendix A
Sample Site Selection Design for MAIA Estuaries 1997-98
Two basic sample site selection designs were implemented for the sampling in 1997-98 for MAIA
Estuaries: for estuarine waters treated as a continuous resource, sampling stations were selected randomly
within hexagons of a randomly overlaid grid; and for estuaries treated as discrete resources, a random
selection from a list frame of individual estuarine systems was employed. The approach for continuous
resource is the randomized-tessellation stratified (RTS) design (Stevens 1997). Multiple Density-RTS
(MD-RTS) (Stevens 1997) approach was used for the Delaware Estuary. The basic estimation procedures
are from the report by Heimbuch, et al. (1995), and also appear in an appendix in Strobel, et al. (1995).
The estimation procedures are based upon ratio-type estimators, which constrain the estimates of the
proportion of the area to be no greater than 1. This eliminates the possibility of estimates that are outside
reasonable bounds and reduces the variance of the estimates.
Discrete resource estimation procedure:
For discrete resources, estimates of the proportion of the area and associated variances are computed based
on a random selection from a list of the estuarine systems, with replicate samples taken from a subset of
the selected systems (Cochran 1977). The resulting estimate of the proportion of the area is:
where
Pz = estimated proportion of the area at or below response value of z,
n = number of estuarine systems sampled.
Ai = area of estuarine system i,
«- 1
m,
yt,. = (1 if response value is less than or equal to z,
\0 otherwise
m{ = number of samples in estuarine system i,
Since replicate samples may be obtained only at a subset of the sampled systems (only a subset of total
number of systems is sampled), the formula for the estimated variance taken from Cochran (1977 eq.
11.30) was modified to produce the following estimate of the approximate mean squared error (MSE) of
the estimate for the proportion of the area:
n-\
A2
n*i=l nij
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where.
/!= n/N,
n* = number of estuarine systems with replicate samples,
wi A
Ml - \
A = the total area of estuarine systems in the list frame, and
TV = number of estuarine systems in the list frame.
Continuous resource estimation procedure:
For continuous resources, the estuarine waters are treated as spatially extensive and the Horvitz-Thompson
estimator (Cochran 1977) is used. The proportion of the area estimate is:
where
A
Pz = estimated proportion of the area at or below response value of z,
yt,= (1 if response value is less than or equal to z,
10 otherwise
Ilj = inclusion probability for a station (I/area),
A = the total area of estuarine waters in strata, and
n = number of estuarine systems sampled.
To produce unbiased estimates of variance, joint inclusion probabilities, Ily , must be non-zero. The
variance estimates were obtained by applying the Yates-Grundy estimate of variance (Cochran 1977) and
using an approximation for the joint inclusion probability:
UiYlj-YIij .
•1 n n
A2 ,-=1 >i
where
II y = joint inclusion probability, probability that stations i and j are selected for sampling,
The approximation for joint inclusion probability assumes that sites are a simple random sample over
the continuous population.
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Procedure for combining estimates for strata
The estimate for the proportion of the area for multiple strata is the weighted average of the proportion
of the area estimates of the individual strata:
where.
A
U = the estimated proportion area for the combined strata,
Pf = the estimated proportion area for the stratum i, and
wt = relative area of stratum i, (area of stratum z'/total area for combined strata).
The estimated variance for the proportion of the area in the combination of strata is the sum of the
component variances:
var(U)= £w,.var(P,)
where.
var(U) = the estimated variance of the proportion of area in the geographic area of interest, and
A
var(Pf) = the estimated variance of the proportion of area in stratum i.
These methods for estimation of the combined strata are based on the assumption that the strata are
independent.
Procedure for combination intervals
To produce confidence intervals (CIs), the proportion of the area estimates are assumed to be normally
distributed. The 95% CIs are based on:
CI = ± 1.96
For small sample sizes, the normal approximation may not be acceptable. A different form has to be used:
exact binomial CIs. However, the exact binomial CI can be used only for constant inclusion probabilities.
For variable inclusion probabilities, the distribution of the percent area is not binomially distributed, and
normal approximate CIs are the more appropriate intervals to use regardless of the sample size.
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Table A-1. Initial Strata Used in Selection of Sampling Sites for MAIA Estuaries 1997-98.
Major tributaries (mainstem portion only)
Delaware River Rappahannock River
Choptank River York River
Patuxent River James River
Potomac River (benthic/sediment quality) Chowan River
Lower Potomac River (water quality) Neuse River
Upper Potomac River (water quality)
Chesapeake Bay subsystems
eastern tributaries
Pocomoke Sound (water quality)
Tangier Sound (water quality)
Tangier/Pocomoke Sound (benthic/sediment quality)
Small estuarine systems in MAIA
Intensively-sampled small estuarine systems
Schuylkill River St Jerome Creek
Salem River Pamunkey River
Severn River Mobjack Bay
Soutn River Cherrystone Inlet
Eastern Bay Sinepuxent Bay
Pocomoke River Virginia coasta| bays
Chesapeake Bay mainstem
water quality - single stratum
benthic/sediment quality - separate strata for Maryland and Virginia waters
Delaware Bay
Chincoteague Bay
Albemarle-Pamlico estuarine system open-water area
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Table A-2. Combinations of Strata Used to Produce Estimates for Geographic Areas.
Delaware Estuary
small estuarine systems
Delaware River
Delaware Bay
Chesapeake Bay
mainstem (one stratum for water quality, two strata for benthic/sediment quality)
tributaries
subsystems
small estuarine systems
Potomac River (water quality)
Lower Potomac River
Upper Potomac River
Coastal Bays
small estuarine systems
Chincoteague Bay
Albemarle-Pamlico Estuarine system
open-water area (large system class)
tidal rivers
small estuarine systems
Tributaries
mainstem portion of tributary
small estuarine systems that are part of tributary
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Table A-3. Design Specifics for MAIA Intensively-Sampled Small Estuarine Systems.
design
randomized tessellation stratified (RTS) design uniform
hexagonal grid overlain on each system
one random site selected within each grid
inclusion probabilities
equal within each system, but different values for each
system
estimation procedure
continuous resource equations with uniform inclusion
probabilities for each system
information needs
area for each system
hex grid overlay specifics for each system
Table A-4. Design Specifics for MAIA Randomly-Selected Small Estuarine Systems.
design
inclusion probabilities
estimation procedure
information needs
from list frame, random selection of systems to sample one
random site within each system
equal to area of each small estuarine system
discrete resource equations
list of all small estuarine systems
area of each small estuarine system
total area of all small estuarine systems
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Table A-5. Design Specifics for Delaware Estuary (River and Bay).
design
multiple-density, randomized tessellation stratified
(MD-RTS) design (Stevens, 1997)
define strata within estuary for sampling purposes
uniform hexagonal grid is overlain on each strata, three
random site selections are made from each hexagon with
sampling at the first site accessible and meeting criteria
inclusion probabilities
equal inclusion probabilities within each strata with
weighting based upon which site in order of selection
actually sampled (1 for first site, 2/3 for second site, and
1/3 for third site)
each stratum has inclusion probability associated with
area of stratum
estimation procedure
continuous resource equations with unequal inclusion
probabilities
information needs
area for each stratum
strata that are within Delaware estuary
hex grid overlay specifics for each strata
selection order for each site actually sampled
area for Delaware estuary
Table A-6. Design Specifics for Chesapeake Bay Mainstem.
design
basically treated the CBP sites as random sites, one group
for water quality and one group for benthic/sediment quality
inclusion probabilities
for benthic/sediment quality, total area/number of sites
for water quality, total area/number of sites
estimation procedure
continuous resource equations
information needs
hex grid overlay specifics
total area for mainstem used for grid overlay (large system
class for Chesapeake Bay as determined for Virginian
Province effort)
inclusion probabilities
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Table A-7. Design Specifics for Tributaries and Subsystems.
design
inclusion probabilities
estimation procedure
information needs
basically treated the Chesapeake Bay program sites as
random sites within each tributary or subsystem, one group
for water quality and one group for sediment quality;
can treat Potomac River as 2 strata (upper and lower) or
could treat as one with different inclusion probabilities;
Neuse River was overlain with three different grid densities
area of hexagonal grid for each tributary or area of each
tributary divided by number of sites
continuous resource equations
total area for each tributary used for grid overlay
hex grid overlay specifics for each tributary
inclusion probabilities
Table A-8. Design Specifics for Albemarle-Pamlico Estuarine System.
design
list frame for small estuarine systems
randomized tessellation stratified (RTS) design for tidal
rivers and large systems (open water)
inclusion probabilities
small systems - area of each small estuarine system
tidal rivers/large systems - area of hexagon
estimation procedure
discrete resource equations for small systems
continuous resource equations for large systems and tidal
rivers
information needs
inclusion probabilities
hex grid overlay specifics
area of systems and classes
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Appendix B
Methods and Indicators for MAIA Estuaries 1997-98
Samples and in situ measurements were collected for characterization of: (1) physical habitat (depth.
temperature, salinity, dissolved oxygen, pH, water clarity, organic carbon content in sediments, and
grain size of sediments); (2) water quality (dissolved and particulate nutrients, total suspended solids,
chlorophyll a, and phaeophytin); (3) contamination in sediments (total metals, simultaneously-extracted
metals, acid volatile sulfide, PAHs, PCBs, pesticides, butyltins, and sediment toxicity); (4) contaminants
in fish and crab tissue (total metals, PAHs, PCBs, and pesticides); and (5) biotic condition (diversity
and abundance of benthic invertebrates, fish and shellfish, and external pathology and spleen macrophage
aggregates in fish).
Sampling was carried out by the host agency responsible for the station network in the region, i.e.,
NOAA in the Delaware Estuary, NOAA and the University of North Carolina in the APES; NPS in the
Chincoteague Bay; CBP in the Chesapeake Bay; and the U.S. EPA in the Maryland and Virginian coastal
bays and in the intensively-sampled estuaries. Sites in the Delaware Inland Bays were not sampled in the
MAIA estuaries program because they were recently included in an earlier EMAP assessment program
(Chaillou, et al. 1996). Samples for analyses of water, sediment, and benthic community quality were
collected predominantly in 1997. The U.S. EPA and the NPS conducted the fish trawls in 1998. Generally,
samples for all analyses were collected at each station, except in the Chesapeake Bay, where separate
station networks are maintained by the CBP for water, sediment, and benthic analyses; and in the APES,
where water analyses are not routinely performed.
A Hydrolab Datasonde was used to measure in situ values of physical habitat parameters at meter
intervals, and water clarity was determined with a Secchi disk. Water samples were collected with a
5-L Go-Flo® bottle in the surface and bottom layers (one meter from the air and sediment interface,
respectively), and filtered with 0.7-micron glass-fiber filters. The water and filters were frozen for later
analysis. A wide range of nutrient parameters was measured (Table 3-3), including dissolved inorganic
and organic components of nitrogen and phosphorus nutrients, as well as particulate forms. Total nitrogen
concentrations are calculated as the sum of total dissolved nitrogen and particulate organic nitrogen.
Total phosphorus concentrations are calculated as the sum of total dissolved phosphorus and particulate
phosphorus. Replicate field samples were analyzed at 6% of the stations to evaluate the repeatability of the
sampling procedure. Analytical methods are described in D'Elia, et al. (1997).
Sediments were collected with a 0.04-m2 Young-modified Van Veen grab sampler. Surface sediments
(composites of upper 2 cm) were collected from each station and used to measure physical, chemical,
and toxicological characteristics of the sediments. The chemical contaminants are those measured by
the NOAA NS&T program (Valette-Silver 1992). Sediments analyzed for total metals were dried and
completely digested in nitric/hydrofluoric acids (acid persulfate for mercury). For measurement of acid
volatile sulfide (AVS) and simultaneously extracted metals (SEM), wet sediments were treated with 1M
HC1 to release the AVS (USEPA 1991). For the organic analyses, sediments were extracted using the
procedures of NOAA NS&T program (Lauenstein, et al. 1993). All analyses were performed on samples
that were stored frozen.
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Three measures of sediment toxicity were measured: (1) Static, 10-day survival tests for Ampelisca
abdita (ASTM 1991, USEPA 1995) were performed at 20° C and 30 ppt salinity on sediments from 401
stations. Total ammonia concentrations were measured and the sediment flushed if levels were greater
than 20 mg/L. Sediments were considered to be toxic if the survival rate of the amphipods relative
to a corresponding negative control was < 80% at a = 0.05. (2) A solid-phase Microtox® bioassay
was performed on whole sediments (Microbics 1992) at 326 stations. A dilution series of sediment in
2% saline (0.01 to 10% sediment) was inoculated with the photoluminescent bacterium Vibrio fischerii,
incubated for 20 minutes, filtered, and analyzed for remaining luminescence with a Microtox® Model
500 Analyzer. A log-linear regression model was used to determine the ECso (the sediment concentration
that reduced luminescence by 50% relative to a non-toxic control), corrected for moisture content of
the sediment. Muddy sediments can diminish luminescence (Ringwood, et al. 1997); therefore, toxicity
criteria depended on grain size: sediments were considered to be toxic when EC50 was < 0.2% for
silt fractions > 20%, and when ECso was < 0.5% for silt fractions < 20%. (3) An exploratory organic-
extract Microtox® bioassay (Johnson and Long 1998) was performed on sediments from 75 stations. The
sediments were dried with anhydrous sodium sulfate, extracted with dichloromethane, and exchanged
into a mixture of dimethylsulfoxide, toluene, and isopropyl alcohol. A dilution series was prepared from
the extract and analyzed as above. Sediments were considered toxic if the ECso exceeded the ECso for
a reference sediment.
Sediment was also collected separately with a 0.04-m2 Young-modified Van Veen grab sampler for the
purpose of measuring species composition, enumeration, and biomass determination of infaunal and
epifaunal benthic macroinvertebrates. One to three grab samples were taken from each station. The
contents were live-sieved in the field with a 0.5 mm mesh screen, and organisms retained on the
screen were fixed in a 10% buffered formalin with rose bengal for preservation and visualization.
Only organisms larger than 0.5 mm were processed; therefore, groups such as turbellarian flatworms,
nematodes, ostracods, harpacticoid copepods and foraminifera were excluded from the identification
process. Taxa were identified to the lowest possible taxon, usually species; however, because of
complexities involved with precise identification, the following groups of organisms were routinely
identified to the indicated taxonomic level: anthozoa (class), chironomidae (family), hirudinea (class),
nemertinea (phylum), oligochaeta (class), ostracoda (subclass), sipuncula (phylum), turbellaria (class),
and copepoda (order). Biomass was calculated as the dry weight of all specimens of a taxon in a grab
sample, following dehydration at 60° C and combustion in an ash oven at 500° C for 5 hours. These
data were used to compute mean abundances per grab of infaunal species, epifaunal species, spionid
polychaetes, and tubificid oligochaetes; the mean biomass per grab of all species; the total and mean
numbers per grab of infaunal species and epifaunal species; the Shannon-Weiner Index (Shannon and
Weaver 1949) and Gleason's D index (Krebs 1989), which are measures of species diversity; and a
multi-metric benthic community index, developed for species in the Virginian Province, computed using
expressions of species diversity and abundance of opportunistic species (Paul, et al. 1999).
A benthic community index is calculated as a weighted combination of three benthic diversity metrics:
a salinity-adjusted Gleason's index, a salinity-adjusted abundance of tubificids, and the abundance of
spionids. This benthic index was developed with data compiled during the 1990-1993 EMAP effort in the
Virginian Province using discriminant analysis to determine a weighted combination of parameters which
distinguish impacted and unimpacted sites in the EMAP-VP (Paul, et al. 1999). Indices values less than or
equal to zero designate impacted conditions by definition. Stations in the APES are evaluated by a similar
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index derived for the EMAP-Carolinian Province estuarine study (Hyland, et al. 1996). The threshold of
impairment for this index is < 3; therefore, the index scores are adjusted by subtracting 3 from the APES
values and are evaluated using an impairment threshold of zero.
Fish and crab were collected in standard 10-minute trawls, using a 15 m otter trawl towed against the
tide at 1-3 knots. The identity, abundance, average fork length, and frequency and location of visible
pathologies (lumps, growths, ulcers, or fmrot) were determined in ship-board inspections for all fish
species collected in standardized fish trawls. The spleens of three target species - white perch (Morone
americana), spot (Leiostomus xanthurus), and summer flounder (Paralichthys dentatus) - were preserved
for later histological examination for macrophage aggregates, and the concentrations of metals, PAHs,
PCBs, and pesticides were measured in composites samples of summer flounder or blue crab collected
in standard or auxiliary trawls.
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Appendix C
Criteria for Presenting Indicator Data
Surface Water Nutrients - Total Nitrogen (TN). TN was not measured directly in the MAIA-E program;
rather, it was calculated as the sum of total dissolved nitrogen (TDN) and particulate organic nitrogen
(PON). The units of TN are mgN/L, which is equivalent to ppm. There are no firm guidelines for
classifying the nitrogen nutrient condition in estuaries; therefore, we used the 25th and 75th percentile
values of all MAIA-E measurements to define the three map categories. Low TN concentrations are less
than or equal to 0.5 mgN/L; intermediate concentrations are greater than 0.5 to 1.0 mgN/L; and high
concentrations are greater than 1.0 mgN/L. Some monitoring programs measure DIN rather than TN.
DIN is the sum of nitrate, nitrite, and ammonium concentrations. Plants assimilate these simple inorganic
compounds directly; therefore, some would argue the DIN is a better measure of nutrient condition.
However, DIN concentrations vary widely throughout the year in response to complex cycles of supply
and transformation. Surface waters are often nearly depleted of DIN during summer when the MAIA-E
program sampled the estuaries. Since TN is a combination of both dissolved inorganic and organic,
plus particulate organic nutrient compounds, it is a more accurate measure of the overall availability of
nutrients in an estuary. TN will likely be the measure used by regulatory agencies in the future to set
nutrient concentration guidelines for estuaries.
Caveats regarding the interpretation. We emphasize that the map categories "low", "intermediate" and
"high" are based on a simple ranking of the MAIA-E data rather than on established guidelines. The
maps accurately show relative TN conditions in the region, but not based on any particular environmental
response such as bloom activity or the survival of sea grasses. The maps indicate TN concentrations
during a single, summertime sampling. It is possible that other nutrient measures are better predictors of
bloom activity, e.g., nutrient availability during spring or regeneration rates of nutrients in sediments. In
part, the MAIA-E program was designed to address such questions regarding interpretation. Finally, high
concentrations of nitrogen nutrients are not necessarily harmful. For instance, highly turbid waters may
prevent excessive plant growth even when abundant nutrients are available. This is the case in much of
the Delaware Estuary and coastal bays.
Surface Water Nutrients - Total Phosphorus (TP). TP was not measured directly in the MAIA-E
program; rather, it was calculated as the sum of total dissolved phosphorus (TOP) and particulate organic
phosphorus. It is a measure of both organic and inorganic dissolved phosphorus species. There are no
firm guidelines for classifying the phosphorus nutrient condition in estuaries; therefore, we used the 25th
and 75th percentile values of all MAIA-E measurements to define the three map categories. Low TP
concentrations are less than or equal to 0.05 mgP/L; intermediate concentrations are greater than 0.05
to 0.10 mgP/L; and high concentrations are greater than 0.10 mgP/L. As with the TN measurements
described above, caution is advised when interpreting the TP maps. The TP map categories are based
on simple ranking of the MAIA phosphorus measurements and may not reflect actual environmental
responses. The maps are accurate displays of the relative availability of TP during summer in the region.
Surface Layer Chlorophyll a. Seawater samples were collected from about 1 meter below the surface
with a 5L Go-Flo® sampling bottle. Water samples were filtered aboard ship with 0.7-micron glass-fiber
filter pads. Chlorophyll a pigments were extracted from the filter with 90% acetone and measured with
a Turner Design TD700 Fluorometer. The results were reported with units of ug/L, which is equivalent
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to parts per billion. Three categories were used to characterize chlorophyll concentrations: good for
concentrations less than or equal to 15 \ig/L;fair for values greater than 15 to 30 ug/L; and poor for
concentrations greater than 30 ug/L. These thresholds were used in preparing a report on the condition of
the MAIA estuaries (Paul, et al. 2000). The threshold value of 15 ug/L is also equal to the restoration goals
recommended for the survival of SAV in the Chesapeake Bay (Batiuk, et al. 2000). While this threshold
value may not be appropriate for SAV restoration in all estuaries, it is a useful reference value.
Sediment Organic Content (%TOC). Total organic carbon contents were labeled as follows: low for
values less than or equal to 1%; as intermediate if greater than 1% to 3%; and as high for values greater
than 3%. The category thresholds are those used in the EMAP-VP study, based on findings in that study
that TOC values greater than 3% were associated with impacted benthic communities (as measured by the
benthic index), while values less than 1% were not (Paul, et al. 1999).
Water Clarity (Secchi Depth). The MAIA-E program characterizes water clarity by reporting the Secchi
depth (SD), which is the depth (in meters) at which a white disk becomes obscured by suspended
material or colored tannins present in the water. Shorter Secchi depths signify more murky water. We
use three categories to describe water clarity: clear waters display Secchi depths greater than 1.0 meter;
intermediate clarity designates Secchi depths greater than 0.3 to 1 meter; and murky conditions are
indicated by Secchi depths less than or equal to 0.3 meter. There are no established criteria for water
clarity; therefore, we use threshold values preciously adopted by EMAP-VP.
Relation to other measures of water clarity. Secchi depths can be compared with the light extinction
coefficient Kd, another parameter used to characterize water clarity. Kd describes the exponential decrease
of illumination \J IQ with water depth z: \J IQ = exp(-Kd*z). Although there is no firm relationship between
Kdand SD, Batiuk, et al. (2000) found an expression which is useful for estuaries: SD*Kd = 1.45. Thus, an
SD of 1.0 meter is equivalent to the transmission of 23% of ambient light at one meter depth, comparable
to the restoration goals recommended for the survival of SAV in the Chesapeake Bay (Batiuk, et al.
2000). While this threshold value may not be appropriate for SAV restoration in all estuaries, it is a useful
reference value for water clarity nonetheless.
Caveats regarding interpretation. The interpretation of water clarity measurements may sometimes be,
pardon the expression, unclear. This is so for at least three reasons. First, measurements of Secchi
depth alone (or light extinction coefficient) cannot distinguish whether the light attenuation is caused
by particulate matter, by living or dead plant material, or by colored substances in the water. Such
identification may be aided by consideration of other parameters such as total suspended solids and
chlorophyll. Most estuarine waters are naturally turbid to some extent, especially in regions where rivers
expel their loads of suspended material and nutrients into a protected water body. However, Secchi depth
measurements alone cannot distinguish between natural and anthropogenic causes of loss of water clarity.
Finally, there is as yet no consensus among researchers regarding criteria for adequate vs. harmful degrees
of water clarity.
Bottom Layer Dissolved Oxygen (DO). Condition categories were considered good for levels greater
than 5 mg/L; fair for concentrations greater than 2 to 5 mg/L; and poor for concentrations less than or
equal to 2 mg/L. EPA's proposed saltwater quality criteria cite DO thresholds of 2.3 and 4.8 mg/L (USEPA
2000b). Most states have set their water quality standard for DO at 5 mg/L.
Caveat: Short-term hypoxic conditions may also occur in shallower water during the night, when oxygen
demand from respiration exceeds supply. This indicator does not measure this effect.
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Sediment Quality - Metal Contamination. This summary uses the approach of Long and Morgan
(1990) to characterize contamination in sediments. These researchers identified a list of nine metals which
induced impairment to biological organisms in estuaries. They specified ERL and ERM for each metal.
The ERL value specifies the concentration of metal that would likely produce adverse effects in 10% of a
population, while the ERM value indicates the concentration that would have an effect rate of 50%. The
metals and respective ERL and ERM values (mg/g dry wt or ppm) are: arsenic: 8.2, 70; cadmium: 1.2.
9.6; chromium: 81, 370; copper: 34, 270; lead: 46.7, 218; mercury: 0.15, 0.71; nickel: 20.9, 51.6; silver:
1.0, 3.7; and zinc: 150, 410. These values were taken from Long, et al. (1995). Three categories are
presented on the maps. Good signifies no ERL exceedances; intermediate represents any ERL (but no
ERM) exceedance, and poor indicates an ERM exceedance.
Sediment Quality - Organic Contamination. The Long and Morgan (1990) approach is also used
to characterize contamination levels of organic compounds in sediments (see description above). The
following nineteen compounds and respective ERL and ERM values were used to prepare the maps in this
summary report: acenaphthene: 16, 500; acenaphthylene: 44, 640; anthracene: 85, 1100; fluorene: 19, 540;
2-methyl naphthalene: 70, 670; naphthalene: 160, 2100; phenanthrene: 240, 1500; benz(a)anthracene: 261,
1600; benzo(a)pyrene: 430, 1600; chrysene: 384, 2800; dibenzo(a,h)anthracene: 63, 260; fluoranthene:
600, 5100; pyrene: 670, 2600; 4,4'-DDE: 2.2, 27; low MW PAH (sum of 2- and 3-ring PAHs): 550, 3160;
high MW PAH (sum of 4- and 5-ring PAHs): 1700, 9600; total PAH (sum of all measured PAHs): 4000,
45000; total DDT (sum of 2,4' and 4,4' congeners of ODD, DDE and DDT): 1.6, 46; and total PCBs:
23, 180. The units are ng/g (ppb). These values were taken from Long, et al. (1995). Three categories
are presented on the maps. Good signifies no ERL exceedances, intermediate represents any ERL (but no
ERM) exceedance, and poor indicates any ERM exceedance.
Sediment Toxicity (Amphipod Survival). The toxicity of sediments was evaluated using a static ten-day
assay conducted using the amphipod Ampelisca abdita following EMAP procedures (EPA 1994, 1995).
The test is simple in concept - amphipods are added to sediment, and their survival rate is used as an
indicator of sediment toxicity. Results are reported as the average number of amphipods surviving in the
sample tests divided by the number of amphipods surviving in a control sediment, expressed as a percent.
Lower values of this result indicate higher toxicity. The three categories used on the maps are: good when
survival is greater than 80%; fair for values between 60 to 80%; and poor for survival rates less than or
equal to 60%. The same threshold values were employed in the EMAP-VP program.
Sediment Quality - Benthic Index. The EMAP-VP benthic index is a combination of three metrics
into a single index (the metrics are: salinity-adjusted Gleason's index, the salinity-adjusted abundance of
tubificids, and the abundance of spionids). This benthic index was developed with data compiled during
the 1990-1993 EMAP effort in the Virginian Province (Paul, et al. 1999). The majority of values range
from -5 to +5, with positive values signifying healthy conditions and negative values indicating degraded
conditions. On the maps in this summary, the following classifications hold: good when the index is
greater than zero, and poor for values less than zero. The threshold value of zero reflects a defining feature
of the index scale; values greater than zero were similar to pristine reference sites, while negative values
were associated with impaired reference sites.
Number of Fish Species. The MAIA-E program conducted regular fish surveys during the summer of
1998 to characterize the structure and health of the fish communities. The stations sampled were selected
according to the probabilistic design but were not identical with the stations sampled for water and
sediment quality analyses conducted primarily in 1997. Therefore, it is not possible to directly compare
these different analyses station by station. However, it is statistically valid to compare results among
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classes of estuaries, e.g., large versus small estuaries, Delaware Estuary versus Chesapeake Bay, etc.
Three categories were used to classify species richness: low if the number was two or less; intermediate
for 3 to 5 species; and high for 6 or more species. These categories are the same as those used in the
EMAP-VP.
Fish and Shellfish Tissue Contamination. Representative samples of edible tissue from summer flounder
and blue crabs were analyzed for metallic and organic toxicants. The fish and shellfish were collected in
1998. Table 6-1 lists the analytes and concentration limits considered by USEPAto present risks to human
consumers (USEPA 2000). The limits are based on human health risk assessment and are considered
to be protective of recreational, tribal, ethnic, and subsistence fishers who are likely to consume more
fish than the general population. A site was classified as poor if a limit for any analyte in Table 6-1
is exceeded.
82
-------
Appendix D
Values of Indicator Parameters
83
-------
Table D-1. Values of Indicator Parameters Representing Eutrophication.
Red line indicates limit used to demark "high" or "poor" categories on report cards. An arrow indicates off-scale value.
Total Nitrogen (mg/L) Total Phosphorus Chlorophyll a (u,g/L) Total Organic Carbon Secchi Depth (m) Dissolved Oxgyen
(mg/L) (%) (mg/L)
oo
Delaware Estuary
Delaware Bay
Delaware River
Schuylkill River*
Salem River*
Chesapeake Bay
Mainstem
Choptank River
Patuxent River
Potomac River
Rappahannock R
York River
James River
Severn River*
South River*
Eastern Bay*
Pocomoke River*
St. Jerome Creek*
Pamunkey River*
Mobjack Bay*
Cherrystone Inlet*
Coastal Bays
Chincoteague Bay
Sinepuxent Bay*
VA Coastal Bays*
APES**
AP Sounds
Chowan River
Neuse River
0 1
-WfH-
-H-
-H--
-HHHU-
4H-
H-4H-H
-HWrt
HMt
[M 1 1 [1 1
HI
-m-
++HW-
-w-
-m
+ -f
+ H
4HH-
HH- +
HH-
H*W
2 3
H-H-
+ -HH-HI- -HH-
+ -HH-
-m-H-
h
+
+ + +
H- + + +
H-H-
h
h
i- +
- +
-H-
1-
* + +
-H-
H-
0 0.1 0.2 0.3
+ +
-Hf
HH-+I-
+HH-
4fH-
-DH-H
HHW
+-HH-
-
-H-H-
HHHI
-HH-
-WH-
-H-
-H
+m
-I-H-
4*
-HH»H
•+ -H-
4-HH--H- +
-H- -W-
HHH- + + +
+
-H-H- +
H++
++ +
H-
+
-
1- +
-H-
1-
HH- +
0
-m
-HH
H++
_g^.
HH-
HH
HH
-H-
+
-HH
H«
HHH
HHH
-H-
-IH
-H
-»
-m
HW
+
-•-
+-
-HH
-HW
25 50 75 100
f +
1-
H-H- ++
HH- H-
+
~H- +
1 1 II 1 +
H- -H- +
- +
-H- + H+
-HW-
- ++
H--I-
«HH+
HH-
+ +
-H-
+
m-
0 4 8 12
-•H-
-HHH
+ +-
++
-H-H
-i- -m
-m
H-HH
-MUf
-H-HH
-m-
-n-
-n-H-
III 1 Illl
-«-im-
H-W-
-H-H
-1-
-m-
HHH-H-
-H- •
HH- H-
+
m-
I--H- +++
m-
i-
+
++
+
H-
•H- + +
1- -H-+ +
0
HHHH-H-
HHH- +•
H-HH
HHHH-
+ +
HHHH-H
HHH--I-
HHHH- •
-H-H
HHHHHH
-HHH
HHH-
H--I-H
mini
H-HHH-
H-H
HH+H
H-HHHHH
H-HH-H
HHHH-
++ •
H
+-H-
2 3
HHH-H- + +
h ++
H-
•1- +
fl-
fl- + + +
• + +
•1- +
f+
•HHH- +
fl-
HHH- +
•HH-H- + +
•HH-H-
fl- +
0 3 6 9 12
H-HH
+
+ 4
+
+ -H-H-Ht
-H- +
++
+ H-
-•H-4HH»"
4- +
+-!•
H
•
H-
-H-
+
-wm- ++
•HNHW-
•H-IH-I-
-HHH-
HH-
1-
-mm-
m-H-
m-
HHH-
i- -nm- +
i-
H-HfHI-
HH-
•HH-I-
HH»
•*-§-+
-«- +
|||B| n
+4H-
HHMHH
' Intensively-sampled sysyems
'* Albemarle Pamlico Estuarine System
-------
Table D-2. Concentrations of Metals in Sediments. Red line marks ERL concentration.
Arrows indicate off-scale value(s). Units are jj,g/g dry sediment, equivalent to ppm.
00
Delaware Estuary
Delaware Bay
Delaware River
Schuylkill River*
Salem River*
Chesapeake Bay
Mainstem
Choptank River
Patuxent River
Potomac River
RappahannockR
York River
James River
Severn River*
South River*
Eastern Bay*
Pocomoke River*
St. Jerome Creek*
Pamunkey River*
Mobjack Bay*
Cherrystone Inlet*
Coastal Bays
Chincoteague Bay
Sinepuxent Bay*
VA Coastal Bays*
APES**
AP Sounds
Chowan River
Neuse River
Arsenic Lead Mercury
ERL 8.2 ERL 47 ERL 0.15
ERM 70 ERM 270 ERM 0.71
0 20 40 60
-W
-HI
-m
4
4
-HH
4-
4-
4H
-H
4tt
-H-\
4H-
4D-
II II I
-H-
+ -
4if
4Ht
-H
-m
-H4i
-HH
H- +
HHH- 4-4-
4H-
t4H4-
Wl- 4-
4fr
W-
if
1-
H- +
h 1 1 • 1
HI limn | |
t-
4-
l_
H-
«-
H-
1-4-
4-
4H-
0 70 140 210
4BH
-mt
•*--
-HtH
444
44h
+-HI
-•-
-H-
4tHtt
-t+H-
4H4-
4H-
-m-
•H-
44H-
4H-
-*-
-m-
• Ml
-m
-Ht
HHH-H- 4- 4-
II II I
«- +
«H-4-
0.0 0.3 0.6 0.9
4B4
4HH
41-
HKH
4H-
4+
4t4f
-•-
-H-
linn
-HH-
-Ht
-H4-
-W-
HH-
-H-
4H-
-HH-
4K-
-H-
Ht~
-HH-
•44- 4-4-
1 HIM 1
-+•
H-
Ht4H-
4-
t-4-
•H4- 4-
1- 4-
Hf
Nickel
ERL 21
ERM 52
0 40 80 120
••h
Hi
4
HH
.
4
Hh
4
HtH
HH
^B
4H-
•*•
*
+4
HH
HHi
•m
HHI
HUH
W4f
HH-»
HHH-
-W-+* 4
H-
HH-4
HHt-
M-
H-
Ht-
•HI- -IBHh
• +
h
H-
r
m-
h
H-
HH-
h
Silver
ERL1
ERM 3.7
0
•j 1 1||| 1 1
-HHH4HI
44
4*
ii mi i
4-4- 4
-H4-
-HHHH-
+ 444)
44-4-44
4HH-I-
44t44h4
4V44-4
44-H- 4
4H- H-
-H4- -H
44HH-
4H4- 4-
-fr
1 III 1 — T
-Ht-
III ~H"
2 3
44- 4-
4+4- +
Zinc
ERL 150
ERM 410
0 230 460 690
-m
Hi
-Ht
-HH4-
44t
4-4
-1-
41
444
-HHh
HH-
4H-
4H-4
H-lt
4441
HHHf
-m-
4K4-
HH-
-H-4I
-B-HH
44HH-
| HI |
HHH- 4-
IH>
H-
444HHI- 4-
4-
* Intensively-sampled sysyems
** Albemarle Pamlico Estuarine System
-------
Table D-3. Concentrations of Organic Toxicants in Sediments. Red line marks ERL concentration.
Arrows indicate off-scale value(s). Units are ng/g dry sediment, equivalent to ppb.
00
Delaware Estuary
Delaware Bay
Delaware River
Schuylkill River*
Salem River*
Chesapeake Bay
Mainstem
Choptank River
Patuxent River
Potomac River
Rappahannock R
York River
James River
Severn River*
South River*
Eastern Bay*
Pocomoke River*
St. Jerome Creek*
Pamunkey River*
Mobjack Bay*
Cherrystone Inlet*
Coastal Bays
Chincoteague Bay
Sinepuxent Bay*
VA Coastal Bays*
APES**
AP Sounds
Chowan River
Neuse River
Acenaphthylene
ERL 44
ERM 640
0 100 200
+
-mm
HH-
HB-rt
-H-
» H
*
HHH-
HKHH
•W-
44-
-w-
-fr
*
*
+
+ +
+
HH-
HHH-
-H-
-HH- +
+ 4f44f+ ^
-+
f
h +
+
Anthracene Benzo(a)pyrene
ERL 85 ERL 430
ERM 11 00 ERM 1600
0 500 1000
Hi
*
HH
+
+
+
HI
HI
HI
-H
+
+
H-
+
+
+
+
+
+
-H
+
linn mi
h -H- -H-++
h
Hf+
+• +
f
0 1000 2000
+
HMN
H4
-•-
-W-
-n-
++
~H-
H-
HH-
-Wf
U 1
+
H-
H-
H-
H-
+
+
H+
+
+
HH-
Hh
1- +
H- -H--H-
+
+
+
Fluorene
ERL 19
ERM 540
0 180 360
HI
HI
HI
HI
4
HI
HI
H
HI
HI
HI
HI
H
-t
-1
-t
H
4
H)
4
H
4
HI
Bill II II +
4- 44++
f
m-
+
•HH-
H-
4-
+
2-Methyl Napthalene
ERL 70
ERM 670
0 270 540
_„.
HH
-m-
HIH
HUH
Hh
+
HH-
HH
HH
+
+
+
+
*
+
41-
+
++
+
HH
H-HH- 4H- 4-
h 4- 44-4- H- 4-
f
HUf
HH4- 4i-
f
Naphthalene
ERL 160
ERM 2 100
0 800 1600
+
HI
HI
HI
HH
+
+
Hh
-H
+H
+
+
+
+
+
+
+
+
+
+
Hh
HHHHH- 4-
- HH- 4-4-
Ht-
m-
* Intensively-sampled sysyems
** Albemarie Pamlico Estuarine System
-------
Table D-4. Values of Indicator Parameters.
Arrows indicate off-scale value(s). Units are ng/g dry sediment, equivalent to ppb.
00
Delaware Estuary
Delaware Bay
Delaware River
Schuylkill River*
Salem River*
Chesapeake Bay
Mainstem
Choptank River
Patuxent River
Potomac River
Rappahannock R
York River
James River
Severn River*
South River*
Eastern Bay*
Pocomoke River*
St. Jerome Creek*
Pamunkey River*
Mobjack Bay*
Cherrystone Inlet*
Coastal Bays
Chincoteague Bay
Sinepuxent Bay*
VA Coastal Bays*
APES**
AP Sounds
Chowan River
Neuse River
Total PAH
ERL 4000
ERM 45000
0 10000 20000
-i-
-Ht
4H-
-m
+
-B-
4M
-H-
+
-W-
4»
-HH
-H-
+
+
+
4-
4-
+
4-4
+
41-
HH-
4H-
I-HIHI- +
f + -H-
-*
m- +
+ +
H
+
4,4'-DDE
ERL 2.2
ERM 27
0 25 50
H
H
H
H
4
1
-{
4
-t
H
H
H
4
H
1
H
H
H
1
H
4
H
H
4
h
mi ii ii -m — H»-
1-4444 + +
H-
H-
*•
f
1- +
Total DDT
ERL 1 .6
ERM 46
0 160 320
-
-
-
-
-
-
-
HH-HH- +1- +
-HH-+ +
h +
h
H-
WH-
^+
+
H-
Total PCBs
ERL 23
ERM 180
0 210 420
-1
-1
4
HI
4
4
-1
4
4
Hi
4
HI
4
4
4
4
4
4
4
4
4
HI
H
4
H44H- 41- 4
4 4 444- -HH
4444
1-41- 44
4
Sediment Toxicity
(%)
0 50 100
4 4h
4 H4-
•
4 44
4
41-4 4 4H
4
4*
41-4
4
4
4H4
4
t- 4
44
4
4
4
4- 4
4h 4
4
4
4»4-
44
4
4
4H-
4
4
4
t- +
4
Benthic Community
Index
-505
44H
444*
+± +
^ 44
41
44
HWI
4HI
4-W
44-1
4tHH
4+41
4 41
4
444-
.
4H
HHt
+
41-
4-
.
4-
H-M-
«Hf-
4
44H-
IHW4-
H44H-
HifH-
WH-
HH-
H-4
MHH-
III II
HH-H4
HH- +
4H-
m-
mi4f
mw-
- 4 4
(4h 41-
4H-+
4-
4-
4-
* Intensively-sampled sysyems
** Albemarte Pamlico Estuarine System
-------
Page Intentionally Blank
-------
Appendix E
Tabulation of Condition Estimates
89
-------
Table E-1. Percent Estuarine Area Falling in the Condition Categories Used on the Maps in This Report.
The values in parentheses are the 95% confidence limits, and (n) is the number of stations measured.
VQ
O
Large Estuaries (n)
MAIA 303
DELAWARE ESTUARY 63
Delaware Bay 31
Delaware River 30
CHESAPEAKE BAY 143
Mainstem 42
Choptank River 4
Patuxent River 10
Potomac River 9
Rappahannock River 12
York River 8
James River 22
COASTAL BAYS 31
Chincoteague Bay 10
ALBEMARLE PAMLICO 66
Chowan River 10
Neuse River 20
Intensively -Sampled Systems
Schuylkill River 10
Salem River 10
Severn River 29
South River 27
Eastern Bay 10
Pocomoke River 5
St. Jerome Creek 10
Pamunkey River 1 1
MobjackBay 10
Cherrystone Inlet 10
Sinepuxent Bay 5
VA Coastal Bays 1 1
Condition:
Surface 1
low
32 (14)
24 (25)
27 (29)
0 (0)
31 (7)
50 (18)
50 (0)
0 (0)
0 (0)
17 (21)
13 (23)
35 (21)
6 (11)
0 (0)
37 (37)
10 (19)
33 (26)
0 (0)
0 (0)
4 (7)
0 (0)
20 (26)
0 (0)
0 (0)
11 (22)
0 (0)
0 (0)
0 (0)
40 (32)
<=0.5
"otal Nitroge
mid
47 (14)
53 (30)
61 (35)
0 (0)
52 (8)
45 (18)
25 (15)
73 (26)
55 (31)
83 (21)
88 (23)
50 (22)
60 (40)
50 (32)
38 (37)
90 (19)
59 (30)
0 (0)
0 (0)
79 (15)
88 (13)
50 (33)
50 (57)
80 (26)
78 (29)
100 (0)
89 (22)
40 (48)
60 (32)
0.5 to 1
n (mg/L)
high
21 (12)
23 (10)
11 (9)
100 (47)
17 (5)
5 (8)
25 (15)
27 (28)
45 (31)
0 (0)
0 (0)
15 (16)
34 (21)
50 (32)
25 (31)
0 (0)
9 (15)
100 (0)
100 (0)
18 (14)
12 (14)
30 (30)
50 (57)
20 (26)
1 1 (22)
0 (0)
1 1 (22)
60 (48)
0 (0)
>1
Surface Tc
low
57 (14)
8 (15)
9 (18)
0 (0)
63 (7)
83 (13)
0 (16)
9 (17)
18 (24)
67 (27)
50 (35)
30 (20)
0 (0)
0 (0)
62 (37)
10 (19)
57 (31)
0 (0)
0 (0)
32 (18)
4 (8)
80 (26)
0 (0)
40 (32)
0 (0)
70 (30)
0 (0)
0 (0)
0 (0)
<= 0.05
tal Phospho
mid
29 (12)
61 (31)
71 (36)
0 (0)
26 (7)
17 (13)
75 (16)
27 (26)
18 (24)
33 (27)
50 (35)
70 (20)
64 (37)
70 (29)
22 (30)
90 (19)
42 (28)
0 (0)
0 (0)
57 (19)
73 (17)
20 (26)
25 (49)
60 (32)
75 (32)
30 (30)
89 (22)
60 (48)
80 (26)
0.05 to 0.1
rus (mg/L)
high
15 (11)
31 (17)
20 (19)
100 (47)
11 (3)
0 (2)
25 (4)
64 (28)
64 (30)
0 (0)
0 (0)
0 (0)
36 (30)
30 (29)
16 (30)
0 (0)
1 (1)
100 (0)
100 (0)
11 (12)
23 (16)
0 (0)
75 (49)
0 (0)
25 (32)
0 (0)
1 1 (22)
40 (48)
20 (26)
>0.1
Surface
good
69 (13)
71 (29)
76 (33)
37 (21)
71 (8)
84 (13)
75 (15)
64 (28)
45 (31)
33 (27)
50 (35)
50 (22)
86 (27)
100 (21)
63 (33)
100 (0)
59 (30)
80 (26)
0 (0)
59 (18)
27 (17)
30 (30)
100 (0)
50 (33)
64 (30)
100 (0)
50 (33)
40 (48)
100 (0)
<=15
Chlorophyll
fair
16 (10)
26 (21)
21 (22)
63 (56)
15 (7)
14 (12)
0 (3)
27 (26)
18 (24)
42 (28)
25 (31)
30 (20)
9 (12)
0 (16)
15 (25)
0 (0)
41 (28)
20 (26)
30 (30)
34 (18)
42 (19)
50 (33)
0 (0)
30 (30)
27 (28)
0 (0)
50 (33)
60 (48)
0 (0)
15 to 30
a (H9/L)
poor
16 (10)
3 (5)
3 (6)
0 (0)
14 (5)
2 (6)
25 (14)
9 (17)
36 (30)
25 (25)
25 (31)
20 (17)
5 (9)
0 (16)
22 (27)
0 (0)
0 (0)
0 (0)
70 (30)
7 (9)
31 (18)
20 (26)
0 (0)
20 (26)
9 (18)
0 (0)
0 (0)
0 (0)
0 (0)
>30
-------
Table E-1 (con't). Percent Estuarine Area Falling in the Condition Categories Used on the Maps in This Report. The values in
parenthesis are the 95% confidence limits, and (n) is the number of stations measured.
Large Estuaries (n)
MAIA 303
DELAWARE ESTUARY 63
Delaware Bay 31
Delaware River 30
CHESAPEAKE BAY 143
Mainstem 42
Choptank River 4
Patuxent River 10
Potomac River 9
Rappahannock River 12
York River 8
James River 22
COASTAL BAYS 31
Chincoteague Bay 1 0
ALBEMARLE PAMLICO 66
Chowan River 10
Neuse River 20
Intensively -Sampled Systems
Schuylkill River 10
Salem River 10
Severn River 29
South River 27
Eastern Bay 10
Pocomoke River 5
St. Jerome Creek 10
Pamunkey River 1 1
MobjackBay 10
Cherrystone Inlet 10
Sinepuxent Bay 5
VA Coastal Bays 1 1
Condition:
Total (
low
58 (8)
85 (27)
95 (31)
25 (17)
52 (8)
68 (11)
0 (14)
40 (43)
29 (24)
0 (0)
20 (36)
57 (26)
79 (25)
64 (29)
58 (18)
30 (29)
66 (31)
0 (0)
20 (26)
31 (17)
31 (18)
56 (34)
20 (39)
40 (32)
36 (30)
50 (33)
20 (26)
100 (0)
90 (20)
<=1
Drganic Carb
mid
27 (7)
8 (3)
2 (2)
47 (24)
36 (8)
17 (11)
67 (17)
60 (43)
71 (24)
100 (0)
80 (36)
36 (25)
21 (16)
36 (29)
18 (14)
0 (0)
0 (1)
0 (0)
20 (26)
24 (16)
35 (19)
44 (34)
40 (48)
60 (32)
55 (31)
50 (33)
80 (26)
0 (0)
10 (20)
1 to 3
on (%)
high
16 (6)
7 (5)
3 (5)
28 (19)
12 (6)
15 (8)
33 (15)
0 (0)
0 (0)
0 (0)
0 (0)
7 (14)
0 (0)
0 (0)
24 (14)
70 (29)
33 (26)
100 (0)
60 (32)
45 (18)
35 (19)
0 (0)
40 (48)
0 (0)
9 (18)
0 (0)
0 (0)
0 (0)
0 (0)
>3
Water Cla
poor
2 (1)
8 (6)
7 (7)
11 (13)
2 (1)
0 (2)
0 (2)
0 (0)
0 (0)
0 (0)
0 (0)
0 (0)
5 (9)
0 (16)
0 (0)
0 (0)
0 (0)
0 (0)
70 (30)
0 (0)
0 (0)
0 (0)
0 (0)
10 (20)
9 (18)
0 (0)
0 (0)
0 (0)
0 (0)
<=0.3
rity: Secchi
fair
48 (8)
43 (21)
39 (24)
77 (25)
44 (7)
17 (13)
50 (18)
82 (23)
100 (0)
75 (25)
75 (31)
68 (21)
95 (20)
100 (16)
54 (18)
70 (29)
51 (29)
60 (32)
30 (30)
45 (18)
89 (12)
40 (32)
40 (48)
90 (20)
91 (18)
20 (26)
100 (0)
100 (0)
100 (0)
0.3 to 1
Depth (m)
good
50 (8)
49 (29)
55 (33)
11 (11)
54 (7)
83 (13)
50 (18)
18 (23)
0 (0)
25 (25)
25 (31)
32 (21)
0 (0)
0 (0)
46 (17)
30 (29)
49 (30)
40 (32)
0 (0)
55 (18)
11 (12)
60 (32)
60 (48)
0 (0)
0 (0)
80 (26)
0 (0)
0 (0)
0 (0)
>1
Bottom Di!
poor
10 (4)
0 (0)
0 (0)
0 (0)
19 (7)
29 (16)
25 (14)
20 (25)
13 (24)
17 (21)
13 (23)
0 (0)
0 (0)
0 (0)
0 (0)
0 (0)
0 (0)
0 (0)
10 (20)
39 (18)
15 (14)
20 (26)
0 (0)
0 (0)
0 (0)
0 (0)
0 (0)
0 (0)
0 (0)
<=2
ssolved Oxyg
fair
11 (4)
1 (1)
0 (0)
11 (10)
19 (7)
26 (16)
0 (11)
50 (31)
13 (24)
17 (21)
25 (31)
5 (10)
9 (12)
17 (21)
3 (4)
40 (31)
9 (15)
1 1 (22)
20 (26)
32 (18)
41 (19)
10 (20)
50 (57)
10 (20)
9 (18)
20 (26)
0 (0)
0 (0)
0 (0)
2 to 5
en (mg/L)
good
79 (6)
99 (38)
100 (44)
89 (27)
62 (8)
45 (18)
75 (16)
30 (29)
75 (31)
67 (27)
63 (34)
95 (10)
91 (22)
83 (21)
97 (8)
60 (31)
91 (29)
89 (22)
70 (30)
29 (17)
44 (19)
70 (30)
50 (57)
90 (20)
91 (18)
80 (26)
100 (0)
100 (0)
100 (0)
>5
-------
Table E-1 (con't). Percent Estuarine Area Falling in the Condition Categories Used on the Maps in This Report. The values in parenthesis are the 95%
confidence limits, and (n) is the number of stations measured.
Large Estuaries (n)
MAIA 303
DELAWARE ESTUARY 63
Delaware Bay 31
Delaware River 30
CHESAPEAKE BAY 143
Mainstem 42
Choptank River 4
Patuxent River 10
Potomac River 9
Rappahannock River 12
York River 8
James River 22
COASTAL BAYS 31
Chincoteague Bay 10
ALBEMARLE PAMLICO 66
Chowan River 10
Neuse River 20
Intensively-Sampled Systems
Schuylkill River 10
Salem River 10
Severn River 29
South River 27
Eastern Bay 10
Pocomoke River 5
St. Jerome Creek 10
Pamunkey River 1 1
MobjackBay 10
Cherrystone Inlet 10
Sinepuxent Bay 5
VA Coastal Bays 1 1
Condition:
Met.
good
61 (8)
84 (28)
94 (32)
24 (19)
44 (9)
55 (13)
40 (14)
20 (35)
29 (24)
0 (0)
0 (0)
36 (25)
79 (25)
64 (29)
79 (15)
30 (29)
59 (30)
0 (0)
0 (0)
24 (16)
11 (12)
67 (33)
80 (39)
40 (32)
45 (31)
50 (33)
20 (26)
100 (0)
82 (24)
noERL
ils (exceeda
fair
31 (7)
13 (5)
6 (5)
52 (22)
41 (10)
27 (14)
60 (17)
80 (35)
43 (27)
100 (0)
100 (0)
64 (25)
21 (16)
36 (29)
20 (13)
70 (29)
33 (26)
0 (24)
30 (0)
7 (16)
22 (19)
22 (33)
20 (39)
40 (32)
18 (31)
40 (33)
80 (26)
0 (0)
18 (24)
any ERL
noERM
nces)
poor
9 (3)
3 (2)
1 (1)
24 (19)
15 (6)
18 (8)
0 (15)
0 (0)
29 (24)
0 (0)
0 (0)
0 (0)
0 (0)
0 (0)
0 (1)
0 (0)
8 (15)
100 (24)
70 (0)
69 (18)
67 (19)
11 (0)
0 (0)
20 (0)
36 (0)
10 (0)
0 (0)
0 (0)
0 (0)
any ERM
Organ
good
71 (7)
82 (27)
94 (32)
0 (0)
62 (8)
69 (11)
80 (14)
80 (35)
57 (27)
80 (25)
100 (0)
36 (25)
89 (24)
100 (0)
80 (15)
40 (31)
91 (29)
0 (0)
10 (20)
31 (17)
33 (18)
78 (29)
80 (39)
100 (0)
73 (28)
90 (20)
30 (30)
100 (0)
91 (18)
no ERL
ics (# excee
fair
28 (6)
14 (6)
6 (6)
67 (25)
36 (8)
29 (11)
20 (14)
0 (0)
43 (27)
20 (25)
0 (0)
64 (25)
11 (20)
0 (0)
20 (13)
60 (31)
8 (15)
0 (24)
80 (20)
14 (18)
30 (19)
11 (29)
20 (39)
0 (0)
18 (24)
10 (20)
60 (30)
0 (0)
9 (18)
any ERL
no ERM
dances)
poor
1 (1)
4 (2)
0 (0)
33 (19)
1 (2)
2 (4)
0 (0)
20 (35)
0 (0)
0 (0)
0 (0)
0 (0)
0 (0)
0 (0)
0 (0)
0 (0)
0 (1)
100 (24)
10 (0)
55 (7)
37 (12)
11 (0)
0 (0)
0 (0)
9 (18)
0 (0)
10 (0)
0 (0)
0 (0)
any ERM
Sedimer
poor
1 (0)
2 (2)
0 (0)
15 (18)
0 (0)
0 (0)
0 (1)
0 (0)
0 (0)
0 (0)
0 (0)
0 (0)
0 (0)
0 (0)
1 (0)
40 (31)
0 (0)
14 (28)
0 (0)
0 (0)
0 (0)
0 (0)
0 (0)
0 (0)
18 (24)
0 (0)
10 (20)
0 (0)
0 (0)
<=60
it Toxicity (1
fair
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)
1 (0)
40 (31)
0 (0)
57 (40)
0 (0)
4 (7)
0 (0)
0 (0)
0 (0)
0 (0)
9 (18)
0 (0)
0 (0)
0 (0)
0 (0)
60 to 80
fa survival)
good
99 (3)
98 (26)
100 (30)
85 (21)
100 (0)
100 (0)
100 (1)
100 (0)
100 (0)
100 (0)
100 (0)
100 (0)
100 (18)
100 (0)
99 (4)
20 (25)
100 (27)
29 (36)
100 (0)
96 (7)
100 (0)
100 (0)
100 (0)
100 (0)
73 (28)
100 (0)
90 (20)
100 (0)
100 (0)
>80
Benth
poor
37 (8)
36 (29)
36 (33)
38 (21)
35 (7)
30 (10)
0 (17)
44 (18)
56 (20)
32 (18)
52 (18)
32 (18)
25 (30)
9 (23)
41 (17)
40 (31)
50 (29)
83 (33)
40 (32)
62 (18)
59 (19)
33 (33)
20 (39)
60 (32)
0 (0)
40 (32)
80 (26)
0 (0)
30 (30)
<=0
ic Index
good
63 (7)
64 (17)
64 (19)
62 (25)
65 (7)
70 (10)
100 (17)
56 (18)
44 (20)
68 (18)
48 (18)
68 (18)
75 (23)
91 (23)
59 (18)
60 (31)
50 (29)
17 (33)
60 (32)
38 (18)
41 (19)
67 (33)
80 (39)
40 (32)
100 (0)
60 (32)
20 (26)
100 (0)
70 (30)
>0
VQ
to
-------
Appendix F
Statistical Correlation
Coefficients Among Selected Indicators
93
-------
VQ
Table F-1. Pearson Correlation Factors Among Indicated Indicators. Values range from +1 (high linear relationship between
data sets) through zero (complete absence of a relationship) to -1 (high inverse linear relationship). Only values in blue are
statistically significant, with greater than 95% certainty.
Surface Chlorophyll versus
Water
Depth
Delaware Estuary
Schuylkill River
Salem River
Chesapeake Bay
Severn River
South River
Eastern Bay
Pocomoke River
St. Jerome Creek
Pamunkey River
Mobjack Bay
Cherrystone Inlet
Coastal Bays
Sinepuxent Bay
VA Coastal Bays
Albemarle Pamlico
-0.48
0.61
-0.79
-0.33
-0.09
0.09
0.55
0.90
-0.23
0.15
-0.62
-0.26
-0.19
0.38
-0.09
-0.20
Bottom
Salinity
0.07
N/A
-0.64
-0.59
0.10
-0.39
0.58
1.00
-0.65
0.75
-0.72
-0.29
-0.78
-0.97
-0.30
-0.03
Water
Stratif
-0.12
-0.17
-0.16
-0.35
-0.09
0.09
0.54
N/A
N/A
0.58
-0.57
0.49
0.10
N/A
-0.19
0.23
Seech i
Depth
-0.10
0.19
-0.72
-0.49
-0.51
-0.47
-0.02
-0.87
-0.78
-0.66
-0.43
-0.69
-0.47
-0.45
-0.07
-0.61
Surface
Chi a
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Bottom
Diss Oxy
0.41
-0.86
-0.71
0.30
0.20
0.02
-0.61
0.32
-0.67
0.16
0.24
-0.47
0.34
0.46
-0.46
0.25
Surface
TotN
0.24
-0.54
-0.02
0.56
0.66
0.88
0.53
0.58
0.98
0.23
0.56
0.06
0.65
0.94
0.50
0.71
Surface
TotP
0.32
-0.91
0.90
0.51
0.47
0.57
-0.06
0.67
0.93
0.53
0.41
0.10
0.81
0.77
0.41
0.03
TN/TP
Ratio
-0.09
0.90
-0.86
-0.09
-0.29
-0.33
0.02
0.16
-0.38
-0.60
-0.03
-0.12
0.48
0.55
0.14
0.53
Sediment
Grainsize
0.20
0.71
0.40
-0.14
0.15
0.19
0.62
0.98
0.54
0.62
-0.60
0.64
0.43
0.38
-0.08
0.39
Sediment
TOC
0.35
-0.74
0.71
0.43
-0.12
0.20
0.44
0.78
0.64
0.55
-0.56
0.59
0.37
0.30
0.03
0.29
Sed Metals
ERL/ERM
0.15
0.53
0.55
0.48
0.12
0.24
0.73
1.00
0.55
0.59
-0.48
0.53
0.19
N/A
-0.45
-0.01
Sed Org
ERL/ERM
0.20
-0.58
0.51
0.63
0.03
0.38
0.64
1.00
N/A
0.16
-0.46
0.10
0.11
N/A
0.64
0.17
N/A: data not available
Bottom Dissolved Oxygen versus
Water
Depth
Delaware Estuary
Schuylkill River
Salem River
Chesapeake Bay
Severn River
South River
Eastern Bay
Pocomoke River
St. Jerome Creek
Pamunkey River
Mobjack Bay
Cherrystone Inlet
Coastal Bays
Sinepuxent Bay
VA Coastal Bays
Albemarle Pamlico
0.03
-0.32
0.46
-0.63
-0.87
-0.44
-0.95
0.39
0.15
-0.19
-0.76
0.04
-0.12
-0.30
-0.22
-0.42
Bottom
Salinity
0.67
N/A
0.14
-0.35
-0.45
0.01
-0.90
0.34
0.69
0.02
-0.36
0.44
-0.40
-0.35
-0.36
0.09
Water
Stratif
0.16
0.27
0.17
-0.59
-0.74
-0.63
-0.92
N/A
N/A
-0.23
-0.70
-0.49
0.01
N/A
-0.19
-0.26
Secchi
Depth
-0.02
-0.15
0.46
-0.26
-0.47
-0.14
-0.41
-0.27
0.40
0.22
-0.39
0.60
-0.08
0.33
-0.22
-0.16
Surface
Chi a
0.41
-0.86
-0.71
0.30
0.20
0.02
-0.61
0.32
-0.67
0.16
0.24
-0.47
0.34
0.46
-0.46
0.25
Bottom
Diss Oxy
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Surface
TotN
-0.60
0.03
-0.05
0.35
0.30
0.14
-0.65
-0.01
-0.58
0.10
0.36
-0.78
0.24
0.40
0.40
0.02
Surface
TotP
-0.30
0.65
-0.56
0.32
-0.02
-0.37
0.02
0.55
-0.63
-0.26
0.32
-0.52
0.26
-0.20
0.40
-0.05
TN/TP
Ratio
-0.53
-0.74
0.59
-0.08
0.21
0.68
-0.48
-0.67
0.44
0.62
-0.09
-0.05
0.32
0.82
0.07
0.07
Sediment
Grainsize
-0.07
-0.80
-0.15
-0.23
-0.73
-0.43
-0.84
0.27
-0.12
0.47
-0.78
-0.54
0.02
-0.17
0.29
-0.07
Sediment
TOC
-0.14
0.85
-0.39
-0.04
-0.73
-0.58
-0.86
0.06
-0.31
0.51
-0.80
-0.43
0.20
-0.21
0.26
-0.19
Sed Metals
ERL/ERM
-0.28
-0.52
-0.22
-0.28
-0.81
-0.61
-0.89
0.34
-0.18
0.31
-0.78
-0.40
0.23
N/A
0.69
-0.19
Sed Org
ERL/ERM
-0.46
0.78
-0.90
-0.12
-0.55
-0.47
-0.78
0.34
N/A
-0.31
-0.27
-0.24
0.29
N/A
-0.35
0.01
N/A: data not available
-------
Table F-1 (con't). Pearson Correlation Factors Among Indicated Indicators. Values range from +1 (high linear
relationship between data sets) through zero (complete absence of a relationship) to -1 (high inverse linear relationship).
Only values in blue are statistically significant, with greater than 95% certainty.
Total Organic Carbon versus
Delaware Estuary
Schuylkill River
Salem River
Chesapeake Bay
Severn River
South River
Eastern Bay
Pocomoke River
St. Jerome Creek
Pamunkey River
Mobjack Bay
Cherrystone Inlet
Coastal Bays
Sinepuxent Bay
VA Coastal Bays
Albemarle Pamlico
Water
Depth
-0.43
-0.80
-0.83
-0.04
0.69
0.64
0.91
0.76
0.51
-0.35
0.94
-0.11
-0.28
0.12
-0.62
0.24
Bottom
Salinity
-0.44
N/A
-0.54
-0.50
0.45
0.03
0.81
0.71
-0.65
0.20
0.71
-0.37
-0.61
-0.37
-0.17
-0.27
Water
Stratif
-0.22
0.53
-0.32
0.12
0.63
0.55
0.89
N/A
N/A
0.06
0.91
0.37
0.13
N/A
0.21
-0.05
Secchi
Depth
-0.26
-0.01
-0.86
0.10
0.15
-0.06
0.30
-0.94
-0.86
-0.37
0.14
-0.77
-0.29
-0.29
-0.65
-0.12
Surface
Chi a
0.35
-0.74
0.71
0.43
-0.12
0.20
0.44
0.78
0.64
0.55
-0.56
0.59
0.37
0.30
0.03
0.29
Bottom
Diss Oxy
-0.14
0.85
-0.39
-0.04
-0.73
-0.58
-0.86
0.06
-0.31
0.51
-0.80
-0.43
0.20
-0.21
0.26
-0.19
Surface
TotN
0.44
0.24
0.19
0.41
-0.28
0.22
0.42
0.09
0.68
0.22
-0.45
0.32
0.59
0.20
0.30
0.02
Surface
TotP
0.53
0.57
0.70
0.30
0.05
0.43
-0.09
0.09
0.75
0.18
-0.63
0.28
0.54
0.40
0.45
-0.18
TN/TP
Ratio
0.07
-0.60
-0.72
-0.18
-0.30
-0.38
0.26
0.01
-0.59
0.16
0.41
-0.08
0.26
-0.04
-0.17
0.07
Sediment
Grainsize
0.66
-0.99
0.91
0.41
0.90
0.90
0.97
0.88
0.97
0.91
0.97
0.92
0.57
0.99
0.92
0.86
Sediment
TOC
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Sed Metals
ERL/ERM
0.80
-0.71
0.89
0.47
0.90
0.93
0.79
0.73
0.88
0.83
0.98
0.87
0.15
N/A
0.87
0.67
Sed Org
ERL/ERM
0.60
0.36
0.35
0.51
0.48
0.68
0.69
0.73
N/A
0.25
0.40
0.46
0.74
N/A
0.24
0.41
N/A: data not available
EMAP VA Province Benthic Index versus
Delaware Estuary
Schuylkill River
Salem River
Chesapeake Bay
Severn River
South River
Eastern Bay
Pocomoke River
St. Jerome Creek
Pamunkey River
Mobjack Bay
Cherrystone Inlet
Coastal Bays
Sinepuxent Bay
VA Coastal Bays
Albemarle Pamlico
Water
Depth
-0.06
0.41
0.65
-0.12
-0.68
-0.51
-0.91
-0.86
-0.35
-0.61
-0.78
0.23
0.09
0.75
-0.86
-0.18
Bottom
Salinity
0.00
N/A
0.09
-0.15
-0.46
-0.22
-0.81
-0.98
0.79
-0.09
-0.68
0.60
0.41
0.26
-0.01
0.13
Water
Stratif
0.09
-0.20
0.21
-0.21
-0.46
-0.33
-0.88
N/A
N/A
-0.17
-0.77
-0.46
0.08
N/A
0.31
0.08
Secchi
Depth
-0.16
0.54
0.58
-0.03
-0.32
-0.07
-0.22
0.70
0.85
0.43
0.03
0.83
0.11
0.61
-0.50
0.11
Surface
Chi a
-0.53
-0.09
-0.71
-0.24
0.01
0.04
-0.52
-0.96
-0.67
-0.37
0.51
-0.47
-0.12
-0.07
0.03
-0.22
Bottom
Diss Oxy
0.01
0.16
0.92
0.22
0.72
0.42
0.80
-0.37
0.56
0.20
0.55
0.43
-0.34
-0.13
0.11
-0.13
Surface
TotN
-0.09
-0.53
-0.17
-0.11
0.06
-0.03
-0.39
-0.67
-0.71
-0.08
0.30
-0.34
-0.36
0.27
0.36
0.07
Surface
TotP
-0.02
0.08
-0.55
-0.07
0.02
-0.22
0.29
-0.85
-0.85
-0.28
0.61
-0.47
-0.32
0.04
0.53
-0.01
TNHP
Ratio
-0.05
-0.12
0.61
0.10
0.10
0.21
-0.38
-0.13
0.84
0.35
-0.50
0.29
0.08
0.44
-0.23
-0.01
Sediment
Grainsize
-0.07
0.38
-0.42
-0.44
-0.68
-0.77
-0.89
-0.88
-0.77
0.02
-0.90
-0.95
-0.20
-0.09
0.47
-0.33
Sed
TOC
-0.19
-0.41
-0.60
-0.20
-0.68
-0.78
-0.89
-0.57
-0.84
-0.05
-0.84
-0.92
-0.82
0.02
0.54
-0.33
Sed Metals
ERL/ERM
-0.26
0.34
-0.50
-0.41
-0.69
-0.68
-0.82
-0.97
-0.84
-0.01
-0.86
-0.89
-0.19
N/A
0.26
-0.37
Sed Org
ERL/ERM
-0.34
-0.62
-0.88
-0.23
-0.62
-0.33
-0.75
-0.97
N/A
0.07
-0.42
-0.53
-0.70
N/A
0.26
-0.05
N/A: data not available
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Appendix G
Values of Condition Estimates in Common MAIA
and EMAP Indicators
Table G-1. Changes in Environmental Conditions Measured Between the 1990-1993 EMAP-VP and
1997 MAIA-E Studies. Change was calculated as the difference in condition estimates (the percent
of the estuarine area that exceeds a designated value of impairment). This difference is considered
to be statistically significant if the 95% confidence intervals of the MAIA-E AND EMAP-VP condition
estimates were non-overlapping. Red entries indicate a degradation of condition overtime; green
designates improvement; and the absence of color signifies that the estimate ranges overlap
(interpretations regarding change are inconclusive because of measurement uncertainty).
EMAP data: Percent Area degraded ±95% confidence interval (Cl)
Delaware Estuary
Overall
Bay
River
Chesapeake Bay
Overall
Mainstem
Potomac River
Rappahannock River
James River
Bottom DO Bottom DO Metals * Organics * Sed Toxicity Sed Toxicity Benthic Community
<5mg/L <2mg/L in Sediment in Sediment <60% <80% Condition"
0±0
0±0
0±0
3.3 ±4.1
0±0
23.2 ±34.8
0.8 ± 2.7
0±0
7 ± 22.2
0.2 ±1.4
0±0
2 ±11.4
1.1 ±2
0±0
9.2 ±16.5
1.8 ±2.4
0±0
15.4 ±20.1
24.4 ±11. 6
17.7 ±17
69.6 ±21.1
10 ±3.2
11.1 ±4.8
24.5 ±11. 6
15.3 ±11.1
0±0
31.1 ±4.6
37.3 ± 7.1
24.7 ±11. 6
39 ± 20.4
3.9 ±0
5.2 ± 3.1
5.2 ±4.2
0.2 ±0
0±0
7.6 ±10.1
2.7 ±1.9
3.8 ±4.5
0±0
16.8 ±17.1
0±0
0±0
0±0
0±0
0±0
0±0
6.1 ±3
6.6 ± 5.8
1±0
8.9 ±10.6
8±11.4
23.4 ±4.8
18.9 ±5.9
44.1 ±22
43.9 ± 32.7
19.2 ±23.4
MAIA data: Percent Area degraded ±95% confidence interval (Cl)
Delaware Estuary
Overall
Bay
River
Chesapeake Bay
Overall
Mainstem
Potomac River
Rappahannock River
James River
Bottom DO Bottom DO Metals * Organics * Sed Toxicity Sed Toxicity Benthic Community
<5mg/L <2mg/L in Sediment in Sediment <60% <80% Condition**
0±0
0±0
0±0
1.3±1.2
0±0
10.8 ±10.3
3.3 ±1.2
0.5 ± 0.5
23.7 ± 9.3
4±1.1
0±0
33.5 ± 9.6
1.8 ±2.1
0±0
14.9 ±17.8
1.8 ±2.1
0±0
14.9 ±17.8
35.7 ± 14.3
35.9 ±16.4
37.9 ±10.6
19.4 ±7.5
24.6 ±16.2
12.2 ± 23.8
16.7 ±21 .3
0±0
36.7 ±8.5
44.8 ±17.9
25.2 ±31 .2
33.3 ± 26.9
5.3 ±10
22 ±5.4
26.8 ± 7.3
28.6 ± 12.1
0 + 0
0±0
2.2 ±1.9
3.4 ± 3.3
0±0
0±0
0±0
0.3 ±0.3
0±0
0±0
0±0
0±0
0.3 ±0.3
0±0
0±0
0±0
0±0
37±5
28.6 ± 5.4
56 ± 9.8
32 + 9
32 ± 9.1
Change in degraded area between EMAP & MAIA studies: (MAIA - EMAP) ± sum of CIs
Value is significant when it exceeds the sum of the confidence intervals (positive value of estimate = degradation).
Delaware Estuary
Overall
Bay
River
Chesapeake Bay
Overall
Mainstem
Potomac River
Rappahannock River
James River
Bottom DO Bottom DO Metals * Organics * Sed Toxicity Sed Toxicity Benthic Community
<5mg/L <2mg/L in Sediment in Sediment <60% <80% Condition**
0±0
0±0
0±0
-2 ± 5.3
0±0
-12.4 ±45.1
2.5 ± 3.9
0.5 ± 0.5
16.7 ±31 .5
3.8 ± 2.5
0±0
31.5 + 21
0.7 ±4.1
0±0
5.7 ± 34.3
0±4.5
0±0
-0.5 ± 37.9
11. 3 ±25.9
18.2 ±33.4
-31 .7 ±31 .7
9.4 ±10.7
13.5 ±21
-12.3 ± 35.4
1.4 ±32.4
0±0
5.6 ±13.1
7.5 ±25
0.5 ± 42.8
-5.7 ±47.3
1.4 + 10
16.8 + 8.5
21.6 ±11.5
28.4 ±12.1
0±0
-7.6 ±10.1
-0.5 ±3.8
-0.4 ±7.8
0±0
-16.8 ±17.1
0±0
0.3 ±0.3
0±0
0±0
0±0
0±0
-5.8 + 3.3
-6.6 ±5.8
-1±0
-8.9 ±10.6
-8±11.4
13.6 + 9.8
9.7±11.3
11.9±31.8
-11.9±41.7
12.8 ±32.5
* the percent estuarine area exceeding at least one ERM value
** the percent estuarine area exhibiting a benthic index value of zero or less
97
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Appendix H
Index of Environmental Integrity for MAIA Estuaries 1997
Environmental managers require information in a form they can understand and use in their decision-
making. The challenge to scientists is to distill the vast complexity of information about the environment
into something that is useful to and understandable by managers. Information on individual indicators
collected in MAIA Estuaries in 1997-98 is discussed in the main body of this report. The summarization,
or "integration", of the information on the individual indicators is in the form of an environmental report
card. This report card is similar to the environmental report cards in the MAIA resource reports (Jones, et
al. 1997; USEPA 1998; USEPA 2000). Multimetric approaches, which are intended to make it easier for
managers to use ecological data in their decision-making, are also being explored as an additional way of
integrating information from individual indicators (Paul 2002).
Multimetric approaches are used to combine information in the environmental report card into an
overall assessment. This is driven by the desire of managers for information which can be used for
comparative assessments and evaluation of conditions for geographic regions. To do this, a common basis
for comparison is needed. Therefore, an index of environmental integrity (IEI) for the mid-Atlantic
region has been developed for conducting multiresource assessments, i.e., to evaluate the overall condition
of the region (Paul 2002). The index starts with information in the environmental report cards for
individual resources. This information is then aggregated across indicators, spatial scales, and resources.
An hierarchical multimetric approach is used to construct the index. It is assumed that individual metrics
that make up the index respond to stress. Uniform scaling is applied to the individual metrics in the index.
The index is then constructed by simple averaging of the metrics at each level of aggregation.
The IEI builds upon the tenets of the Index of Biotic Integrity (IBI) approach developed by Karr (Karr
1981; Karr and Chu 1999): it is a simple sum of individual metrics that respond monotonically to
environmental stress; it scales the metrics uniformly; and it retains the information from the individual
metrics. The index also relies on the scientific validity of the indicators underlying the environmental
report cards. However, there are three differences from the IBI: the IEI assumes that the stress-response
relationships for the metrics have been established and validated, whereas the IBI develops explicit dose-
response relationships; the IEI responds to anthropogenic and natural stress, while the IBI deals with only
anthropogenic stress; and the IEI is based not only on biological information as the IBI, but includes
information on habitat and human use, making it an environmental index.
Paul (2002) used the environmental report cards for estuaries in the mid-Atlantic (USEPA 1998) and
wadable streams in the mid-Atlantic Highlands (USEPA 2000) to illustrate the IEI approach. lEIs for
estuaries were constructed straightforwardly, by first aggregating spatially within each watershed and
then across the watersheds. Data for lEIs of streams could be aggregated only across watersheds and
ecoregions; they could not be aggregated across states because of the limited coverage in Maryland and
Virginia.
The report card presented in the summary chapter was used to construct lEIs for MAIA-E based on
the 1997 information. The indicator information for eutrophication, sediment contamination, and benthic
condition were used to construct the index. Values of 5, 3, and 1 were assigned to each indicator for each
geographic area in the report card according to the percent area for the indicator exceeding 40%, between
99
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20 and 40 %, or less than 20%, respectively. Here, 5 is used for good condition, 3 for fair, and 1 for poor.
For example, if 21% of the area of a system exhibited bottom dissolved oxygen < 5 mg/1, then a value of 3
was assigned. The result of the assignment of values for the indicators in all of the geographic areas, based
on the data in Figure H-l, is shown in Table H-l.
Table H-1. Assignment of Scores to Geographic Areas for Each Indicator Based Upon Percent
Area Exceeding Thresholds: less than 20% impairment = 5; 20% to 40% = 3; more than 40%
M i ipan 1 1 ici u — i . _ . .
Eutrophication Sediment Contamination _ "TV
Condition
Surface Water Bottom 1 Sediment Sediment Sediment 1 Benthic 1
Chlorophyll Clarity DO Metals Organics Toxicity | Index |
MAIA
DELAWARE ESTUARY
Delaware Bay
Delaware River
*Schuylkill River
*Salem River
CHESAPEAKE BAY
Mainstem
Choptank River
Patuxent River
Potomac River
Rappahannock River
York River
James River
*Severn River
*South River
*Eastern Bay
*Pocomoke River
*St. Jerome River
*Pamunkey River
*Mobjack Bay
"Cherrystone Inlet
COASTAL BAYS
Chincoteague Bay
*Sinepuxent Bay
*Va Coastal Bays
ALBEMARLE-PAMLICO
Chowan River
Neuse River
3 1 3
3 1 5
3 1 5
1 1 5
3 1 5
1 1 3
3 1 3
5 5 1
3 1 3
3 1 1
1 1 3
1 1 3
1 1 3
1 1 5
1 1 1
1 1 1
1 3 3
5 3 1
1 1 5
3 1 5
5 33
1 1 5
5 1 5
5 1 5
1 1 5
5 1 5
3 1 5
5 1 3
1 1 5
335
553
553
1 1 3
1 1 1
1 1 5
1 3 5
1 3 5
1 3 5
1 3 5
1 1 5
1 3 5
1 5 5
1 1 5
1 1 5
1 1 5
335
335
1 5 5
1 3 3
1 5 5
1 1 5
555
555
555
555
555
5 1 1
555
3
1
1
1
1
3
3
3
5
1
1
3
1
3
1
1
3
3
1
5
3
1
3
5
5
3
1
3
1
*system sampled spatially intensively
100
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Aggregations across indicators were used for constructing lEIs. The aggregation for eutrophication-related
indicators was done with only surface chlorophyll a, water clarity, and bottom dissolved oxygen (the
indicators with impact thresholds). The aggregation for sediment contamination was done for metals,
organics, and toxicity. A sediment-quality aggregation was done combining overall sediment contamina-
tion with benthic condition. Finally, an overall IEI for each system was the aggregation of the values for
eutrophication and sediment-quality. These aggregations are shown in Table H-2.
Table H-2. Values for Index of Environmental Integrity for MAIA Estuaries Geographic Areas.
Eutrophication index is the average of chlorophyll a, water clarity, and dissolved oxygen scores
from Table H-1. Sediment contamination is the average of metal, organics and toxicity scores.
Sediment quality is the average of sediment contamination indicators and benthic index. Overall,
the index is the average of all indicators.
MAIA
DELAWARE ESTUARY
Delaware Bay
Delaware River
*Schuylkill River
*Salem River
CHESAPEAKE BAY
Mainstem
Choptank River
Patuxent River
Potomac River
Rappahannock River
York River
James River
*Severn River
*South River
*Eastern Bay
*Pocomoke River
*St. Jerome River
*Pamunkey River
*Mobjack Bay
"Cherrystone Inlet
COASTAL BAYS
Chincoteague Bay
*Sinepuxent Bay
*Va Coastal Bays
ALBEMARLE-PAMLICO
Chowan River
Neuse River
Eutrophication
2.3
3.0
3.0
2.3
3.0
1.7
2.3
3.7
2.3
1.7
1.7
1.7
1.7
2.3
1.0
1.0
2.3
3.0
2.3
3.0
3.7
2.3
3.7
3.7
2.3
3.7
3.0
3.0
2.3
Sediment
Contamination
3.7
4.3
4.3
1.7
1.0
2.3
3.0
3.0
3.0
3.0
2.3
3.0
3.7
2.3
2.3
2.3
3.7
3.7
3.7
2.3
3.7
2.3
5.0
5.0
5.0
5.0
5.0
2.3
5.0
Sediment
Quality
3.5
3.5
3.5
1.5
1.0
2.5
3.0
3.0
3.5
2.5
2.0
3.0
3.0
2.5
2.0
2.0
3.5
3.5
3.0
3.0
3.5
2.0
4.5
5.0
5.0
4.5
4.0
2.5
4.0
Overall
IEI
3.0
3.3
3.3
1.9
1.9
2.1
2.7
3.3
3.0
2.1
1.9
2.4
2.4
2.4
1.6
1.6
3.0
3.3
2.7
3.0
3.6
2.1
4.1
4.4
3.9
4.1
3.6
2.7
3.3
*system sampled spatially intensively
101
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Caution must be emphasized in the interpretation that is placed on the IEI values in Table H-2. A
limited number of indicators was used to determine the values. For example, only surface chlorophyll a,
water quality and bottom dissolved oxygen were used to determine the eutrophication values. Additional
indicators could be incorporated if clearly-defined thresholds are assigned to these additional indicators.
For determining IEI values indicators, it is inappropriate to use thresholds that are based on percentiles
of observed values. That is why total nitrogen and phosphorus were not used in the construction of
the lEIs. A limited number of categories of indicators, was available with no indicators for human use.
This means that the interpretation of the overall IEI score is restricted to aspects of eutrophication and
sediment quality.
The IEI values indicate that eutrophication is of major concern in the Chesapeake Bay, with sediment
quality of concern in the other major systems. Of the intensively-sampled systems, the Schuylkill River
has the lowest value for sediment contamination, while the Severn and South Rivers have the lowest for
eutrophication. Again, these interpretations are limited because of the small number of indicators that
were used to construct the lEIs.
102
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Eutrophication
Sediment
Contamination
Benthic
Community
MAIA
DELAWARE ESTUARY
Delaware Bay
Delaware River
Schuylkill River*
Salem River*
CHESAPEAKE BAY
Mainstem
Choptank River
Patuxent River
Potomac River
Rappahannock River
York River
James River
Severn River*
South River*
Eastern Bay*
Pocomoke River*
St. Jerome Creek*
Pamunkey River*
Mobjack Bay*
Cherrystone Inlet*
COASTAL BAYS
Chincoteague Bay
Sinepuxent Bay*
VA Coastal Bays*
ALBEMARLE-PAMLICO
Chowan River
Neuse River
Impaired when
Total
Nitrogen
21
23
11
100
100
100
17
5
25
27
45
0
0
15
18
12
30
50
20
11
0
11
34
50
60
0
25
0
9
TN
>1 mg/L
Total
Phosp
15
31
20
100
100
100
11
0
25
64
64
0
0
0
11
23
0
75
0
25
0
11
36
30
40
20
16
0
1
TP
>0.1 mg/L
TotOrg
Carbon
16
7
3
28
100
60
12
15
33
0
0
0
0
7
45
35
0
40
0
9
0
0
0
0
0
0
24
70
33
TOG
>3%
Chi a
31
29
24
63
20
100
29
16
25
36
55
67
50
50
41
73
70
0
50
36
0
50
14
0
60
0
37
0
41
CHLa
>15(jg/L
Water
Clarity
50
51
45
89
60
100
46
17
50
82
100
75
75
68
45
89
40
40
100
100
20
100
100
100
100
100
54
70
51
SECCHI
<1 m
Dlss
Oxygen
21
1
0
11
11
30
38
55
25
70
25
33
38
5
71
56
30
50
10
9
20
0
9
17
0
0
3
40
9
DO
<5mg/L
Metals
39
16
6
76
100
100
56
45
60
80
71
100
100
64
76
89
33
20
60
55
50
80
21
36
0
18
21
70
41
MET
Exceed E
Organics
29
18
6
100
100
90
38
31
20
20
43
20
0
64
69
67
22
20
0
27
10
70
11
0
0
9
20
60
9
ORG
RL/ERM
Sediment
Toxicity
1
2
0
15
71
0
0
0
0
0
0
0
0
0
4
0
0
0
0
27
0
10
0
0
0
0
1
80
0
TOX
<80%
Benthic
Index
37 |
36
36
38
83
40
35
30
0
44
56
32
52
32
62
59
33
20
60
0
40
80 |
25
9
0
30
41 I
40
50 |
<0
1 Intensively-sampled systems
Better conditions
Worse conditions
Less than 20% of the estuarine area exhibits high values or impairment
20% to 40% of the area exhibits high values or impairment
More than 40% of the area exhibits high values or impairment
Note regarding color schemes: The thresholds used to define assessment categories for TN, TP, and TOC are developmental
and are under evaluation. Neutral colors are used to characterize these indicators, and interpretation as "high" or "low" may be
more appropriate than "good" or "poor". Categories for other indicators are based on established criteria and may be interpreted as
"impaired" or "unimpaired".
Figure H-1. Environmental Report Card for Mid-Atlantic Estuaries. Based on the percentage of
estuarine area that exceeds the designated impairment threshold. Warm colors (red or orange)
indicate a greater incidence of impaired conditions or excessively high concentrations of a
substance. Numbers in cells are percentages of estuarine area impaired. Refer to Figure 7-1.
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Appendix I
Recommendations for Monitoring Program
Design for Mid-Atlantic Estuaries
Background
The impetus of environmental management is ultimately for a sustainable environment for humans and
other living organisms. The specifics of how one characterizes this sustainable environment depend on
the perspective of the individual. For example, it would be different for economic concerns, recreational
use, or aesthetic pleasure. It is generally accepted that observations of the environment are necessary to
determine how well things are doing and if they are getting better or worse. An observation program
to provide this information does not easily follow. There is a theoretical foundation in the statistical
literature for the design of observation programs (Cochran 1977; Gilbert 1987; Cressie andAldworth
1994; Stehman and Overton 1994). However, the actual design that would be employed to acquire this
information depends on the specific question(s) that is (are) to be addressed with the observations.
Monitoring is a term frequently used to describe the acquisition of data in the environment. The use of
the term monitoring can be put into at least the following categories (Olsen, personal communications):
compliance monitoring, baseline monitoring, trend monitoring, implementation monitoring, effectiveness
monitoring, project monitoring, and validation monitoring. Each of these categories requires the
acquisition of data in a specific fashion to address the types of questions/issues/concerns. The reality is
one monitoring design does not fit all categories. The monitoring design must be specifically matched to
the information needs or the result of the effort may be unnecessarily disappointing.
Probability sampling is an efficient approach for monitoring when it is necessary to collect information
at a finite number of sites and use that information to extrapolate beyond the sampled sites. A probability
design is one in which every element in the population has a known (non-zero) probability of being
selected from the population. There are four different types of probability sampling (simple random
sample, systematic sample, stratified sample, and cluster sample), each with different characteristics.
Stevens, 1997, discusses additional specific implementations of probability sampling. The important point
is that one needs to be more specific than just saying a probability sampling design was used.
Large spatial applications of probability survey designs were implemented in estuaries of the northeastern
and Gulf of Mexico areas of the U.S. in the early 1990s by USEPA's EMAP (Holland 1990; Paul, et al.
1992; Summers, et al. 1993; Summers, et al. 1995). The foundation of the EMAP approach to monitoring
a condition is probability sampling that provides the basis for estimating resource extent and condition, for
characterizing trends, and for representing spatial pattern, all with known levels of confidence. Therefore,
in terms of the monitoring categories listed above, the MAIA-E design may be described as including
baseline monitoring, trend monitoring, and effectiveness monitoring. These early designs were variants
of the RTS implementation of probability sampling (Stevens, 1997). One drawback to the actual
implementations of these designs was the inability to incorporate existing non-probability monitoring sites
into the overall design.
As discussed in this report, the implementation of the MAIA-E program in 1997-98 was done in
conjunction with existing benthic and water quality monitoring programs in the Chesapeake Bay. The
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basic RTS design was used for the program. The U.S. EPA's National Coastal Assessment (NCA)
is a current EMAP geographic initiative. This five-year program (2000-2004) focuses on surveying
the condition of the Nation's coastal resources (estuaries and offshore waters) through an integrated,
comprehensive coastal monitoring program among the coastal states to assess coastal ecological
condition. The approach for NCA focuses on a strategic partnership with all 24 U.S. coastal states.
Using compatible probability designs and a common set of survey indicators, each state is surveying
and assessing the condition of their coastal resources independently. These data can then be used to
develop statements of condition at multiple scales. Table 1-1 summarizes the evolution and advancements
in sampling designs which have resulted from the studies. The next section discusses specifics of the
sampling design as implemented in the northeastern states for NCA. This is followed by the monitoring
program design recommended for the mid-Atlantic estuarine waters.
Design Implemented in National Coastal Assessment in the Northeastern U.S.
The probability sampling design used in NCA for the northeastern U.S. has evolved from earlier designs
to provide increased flexibility in the actual implementation. The basic design is as follows:
- Define the statistical population as estuarine waters delineated by GIS from NOAA charts.
- The grid is randomly placed (origin and orientation) using the random placement selected for
EMAP-VP program.
- Tessellate grid to get approximate number of desired grid cells over target population.
- Randomly select point for each grid cell. Point is restricted to lie in the target population
within the grid cell.
This last step in the design (as opposed to the random point anywhere within the grid, whether on land
or water) permits possible incorporation of existing monitoring program sites into the design, increasing
flexibility in implementing the program.
Before existing monitoring program sites were evaluated for incorporation into the probability design, data
collected from existing sites must be confirmed to meet the quality assurance protocols specified by the
program. This is to ensure that the statistical inferences made from these data are not compromised. Once
this has been done, the evaluation of the site selection can proceed.
If existing monitoring program sites were selected using a probability design, then they can be
incorporated directly into the design. For example, some state fish trawl programs use a stratified random
design for site selection, with stratification usually based upon depth and habitat. Cox and Piegorsch
(1996) discuss procedures for combining samples collected with different probability designs. However,
a comparison needs to be made of the target population of the stratified random design with the target
population for the program. If the existing program does not include all of the target population, then the
existing program sites would need to be supplemented with additional sample sites over the remainder
of the target population.
For existing monitoring program sites that were not selected using a probability design, the process to
determine if the sites can be incorporated into the design is based upon the two concepts identified in
Overtoil, etal. (1993):
1. The sites are identified with a subset of the population, and
2. The sites are similar to a probability sample of the same subset of the population.
106
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These concepts were converted into criteria that were used for evaluating whether or not the existing
monitoring sites could be considered for incorporation into the design. The criteria were:
1. The sites must have been selected initially to be representative of the area from which they
were selected. For example, sites that do not satisfy this criterion would include those targeted
for an outfall discharge location, the end of a dock, or a bridge overpass (for convenience
in acquiring samples).
2. The distribution of individual variables from the existing monitoring sites must be equivalent to
the distribution for probability samples from the same subset of the statistical population. For
example, cumulative distribution functions (CDFs) of bottom dissolved oxygen concentration
can be compared. A CDF displays the estimated portion of the population above and below
any specified value of the variable. This criterion requires that data from probability samples be
available for the population subset of interest.
These two criteria are required to be met before the existing sites are determined to be acceptable for
incorporation into the design. Because of the limited availability of existing probability data for multiple
parameters, a third criterion was considered as confirmatory, but was not required.
3. The correlation structure between variables from the existing monitoring sites must be
equivalent to the correlation structure for probability samples from the same subset of the
statistical population. This criterion requires that information on multiple variables from the
probability sample be available for the population subset of interest.
Recommendation for Monitoring Program Design for Mid-Atlantic Estuarine Waters
The recommendation for the sampling design for mid-Atlantic estuarine waters is to incorporate, where
possible, existing ongoing monitoring program sites using the procedure developed for NCA as discussed
above and to supplement with new sites where existing sites are absent. If multiple existing sites are
within a grid cell, then one of the sites would be randomly selected. As a first step in implementing this
recommendation, it is necessary to determine which of the existing program sites do meet the criteria
for possible incorporation. One would not have a rationale of incorporating the sites if they did not
meet the criteria. It is understood that some assumptions may need to be made for judging the sites
against the criteria. These assumptions need to be documented as part of the actual design that would
be implemented.
With this recommended design, an hierarchical spatial sampling design can be implemented, where data
collected at the various scales can be put together for an overall estimate of condition. The hierarchical
design uses the basic procedure outlined above but employs differing densities of grid, depending on the
allocation of sites (and associated uncertainty) for the different areas. For example, a grid of 50 cells
could be overlain on the mainstem of Chesapeake Bay, with grids of densities, say 10, overlain on systems
such as the Severn and South Rivers. Estimates of condition could be made on these small systems with
inherent uncertainty associated with sample size of 10. These data would be combined with the remaining
sites in the Bay to assess the overall condition of the Bay.
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Table 1-1. Progression of EMAP Probability Sampling Designs in the Northeast.
Program
Survey Design
Incorporation of
Existing Program Sites
EMAP-Virginian
Province
1990-93
sampling classes (strata) based on physical
extent
separate design for each class
large systems - tessellated, center point chosen
small systems - list frame, random start for 1 st
year, all systems over 4 yrs
tidal - rib & spine
none possible
MAIA Estuaries
1997-1998
RTS (random tessellated stratified) for each
strata
large - tessellated, random point w/in cell
small - list frame
equal weights within each strata
incorporate other
sites for entire strata
National Coastal
Assessment
2000-2004
RTS with variable weights for each strata
sites restricted to estuarine resource
criteria for possible use of
existing sites
strata may contain mix of
existing and survey sites
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Appendix J
MAIA Estuaries Partners
Mid-Atlantic Integrated Assessment
(MAIA)
701 Mapes Road
Fort Meade, MD 20755-5053
Phone:410-305-2751
Fax:410-305-3095
http://www.epa.gov/maia
Environmental Monitoring and
Assessment Program (EMAP)
Mail Code :B3 05-01
Research Triangle Park, NC 27711
Phone: 919-541-2281
Fax: 919-541-4324
http://www.epa.gov/emap
EPA's Office of Research and
Development
Ariel Rios Building
1200 Pennsylvania Avenue, N.W.
Washington, DC 20460
Phone: 202-564-6620
Fax: 202-565-2910
http://www.epa.gov/ord/index.htm
EPA Region 2 (NJ, NY, PR, VI)
290 Broadway
New York, NY 10007-1866
Phone: 212-637-3000
Fax: 212-637-3526
http://www.epa.gov/region2/
EPA Region 3 (DE, DC, MD, PA, VA, WV)
1650 Arch Street
Philadelphia, PA 19103-2029
Phone:215-814-5000
Fax:215-814-5103
http://www.epa.gov/region3/
EPA Region 4 (AL, FL, GA, KY, MS, NC,
SC,TN)
61 Forsyth Street
Atlanta, GA 30303-3104
Phone: 404-562-9900
Fax:404-562-8174
http://www.epa.gov/region4/
EPA's Office of Water
National Estuary Program
U.S. EPA (4504T)
Ariel Rios Bldg.
1200 Pennsylvania Ave. N.W.
Washington, DC 20460
Phone: 202-566-1240
Fax: 202-566-1336
http://www.epa.gov/owow/estuaries/
Albemarle-Pamlico National Estuary
Program
1617 Mail Service Center
Raleigh, NC 27699-1617
Phone: 919-733-5083 ext. 585
Fax:919-715-5637
http://h2o.enr.state.nc.us/nep/
Delaware Estuary Program (DE/NJ/PA)
25 State Police Drive (P.O. Box 7360)
West Trenton, NJ 08628-0360
Phone: 609-883-9500
Fax: 609-883-7801
E-mail: delep@delep.org
http://www.delep.org/
Delaware Inland Bays Program
467 Highway 1 (P.O. Box 297)
Lewes, DE 19958
Phone: 302-645-7325
Fax:302-645-5765
http://www.inlandbays.org/
109
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Maryland Coastal Bays Program
9609 Stephen Decatur Highway
Berlin, MD 21811
Phone:410-213-2297
Fax:410-213-2574
E-mail: director@mdcoastalbays.org
http://www.mdcoastalbays.org/
Chesapeake Bay Program
410 Severn Avenue
Suite 109
Annapolis, MD 21403
Phone: 800-YOUR-BAY
Fax:410-267-5777
http://www.chesapeakebay.net/
Delaware River Basin Commission
P.O. Box 7360
West Trenton, NJ 08628-0360
Phone: 609-883-9500
Fax: 609-883-9522
http://www.state.nj.us/drbc/
Delaware Department of Natural
Resources and Environmental Control
89 Kings Highway
Dover, DE 19901
Phone: 302-739-4403
http://www.dnrec.state.de.us/dnrec2000/
Maryland Department of Natural
Resources
580 Taylor Ave
Annapolis, MD 21401
Phone:410-260-8100
http://www.dnr.state.md.us/index.asp
National Park Service
Assateague Island National Seashore
7206 National Seashore Lane
Berlin, MD 21811
Phone:410-641-1441
http://www.nps.gov/asis/index.htm
New Jersey Department of Environmental
Protection
P. O. Box 402
Trenton, NJ 08625-0402
Phone: 609-292-2885
Fax: 609-292-7695
http://www.state.nj.us/dep/
North Carolina Department of
Environment and Natural Resources
1601 Mail Service Center
Raleigh, NC 27699-1601
Phone: 919-733-4984
Fax:919-715-3060
http://www.enr.state.nc.us/
Pennsylvania Department of
Environmental Protection
16th Floor
Rachel Carson State Office Building
P.O. Box 2063
Harrisburg, PA 17105-2063
Phone: 717-787-5267
Fax: 717-787-9549
http://www.dep.state.pa.us/
Virginia Department of Environmental
Quality
P.O. Box 10009
Richmond, VA 23240-0009
Phone: 804-698-4000
http://www.deq.state.va.us/
National Oceanic and Atmospheric
Administration
National Ocean Service
SSMC4, 13th floor
1305 East West Highway
Silver Spring, MD 20910
Phone: 301-713-3070
E-Mail: nos.info@hermes.nos.noaa.gov
http://www.nos.noaa.gov/
110
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References
American Society for Testing and Materials (ASTM). (1991). Guide for conducting 10-day static sediment
toxicity tests with marine andestuarine amphipods, ASTM Standard Methods, 11.04, Method Number
E-1367-90, ASTM, Philadelphia, PA.
Batiuk, R.A. and 15 others. (2000). "Chesapeake Bay submerged aquatic vegetation water quality and
habitat-based requirements and restoration targets: A second technical synthesis". EPA Chesapeake
Bay Program Report, Annapolis, MD.
Boynton, W.R., Murray, L., Kemp, W.M., Hagy, J.D., Stokes, C., Jacobs, F., Bowers, J., Souza, S., Rinsky,
B., and Seibel, J. (1993). "Maryland's Coastal Bays: An assessment of aquatic ecosystems, pollutant
loadings and management options." Maryland Department of the Environment, Baltimore, MD.
Bricker, S.B., Clement, C.G., Pirhalla, D.E., Orlando, S.P, and Farrow, D.R.G. (1999). "National
Estuarine Eutrophication Assessment: Effects of nutrient enrichment in the nation's estuaries."
NOAA, National Ocean Service, Special Projects and the National Centers for Coastal Ocean Science.
Silver Spring, MD: 71 pp.
Brongersma-Sanders, M. (1957). "Mass mortality in the sea". In Treatise on Marine Ecology and
Paleoecology, J.W. Hedgepeth (Ed.). Geol. Soc. Amer. Memoir 67(1): 941-1010. National Academy
of Sciences, Washington, DC.
Chaillou, J.C., Weisberg, S.B., Kutz, F.W., DeMoss, T.E., Mangiaracina, L., Magnien, R., Eskin, R.,
Maxted, J., Price, K. and Summers, J.K. (1996). "Assessment of the Ecological Condition of the
Delaware and Maryland Coastal Bays." EPA/620/R-96/004. U.S. Environmental Protection Agency,
Office of Research and Development, Washington, DC.
Cochran, W.G. (1977). Sampling Techniques. John Wiley & Sons, New York.
Cox, L.H. and W.W. Piegorsch. (1996). "Combining environmental information in environmental
monitoring, measurement and assessment". Environmentrics 7: 299-308.
Cressie, N. and J. Aldworth. (1996). Spatial statistical analysis and its consequences for spatial sampling.
In Proceedings of the Fifth International Geostatistics Congress. E. Baafi. Dordrecht, Kluwer.
D'Elia, C.F., Connor, E.E., Kaumeyer, N.L., Keefe, C.W., Wood, K.V., and Zimmermann, C.F. (1997).
Nutrient Analytical Services Laboratory Standard Operating Procedures. Technical Report Series
#158-97. Chesapeake Biological Laboratory, University of Maryland Center for Environmental
Science, Solomons, MD: 77 pp.
Gilbert, R.O. (1987). Statistical Methods for Environmental Pollution Monitoring. VanNostrand Reinhold,
New York.
Ill
-------
Heimbuch, D.G., Wilson, H.T., Robson, D.S. and Summers, J.K. (1995). "Design-based estimation of
the proportion of area degraded and associated variance estimators for EMAP-Estuaries sampling
in the Louisianian and Virginian Provinces: 1990-1994". Draft report prepared for U.S. Environmental
Protection Agency by Coastal Environmental Services, Linthicum, MD.
Holland, A.F. (Ed.). (1990). "Near Coastal Plan for 1990: Estuaries". EPA 600/4-90/033, Office of
Research and Development, U.S. Environmental Protection Agency, Narragansett, RI.
Hyland, J.L., Snoots, T.R., and Balthis, W.L. (1996). "Sediment quality of estuaries in the Southeastern
U.S." Environmental Monitoring and Assessment 51: 331-343.
Johnson, B.T., and Long, E.R. (1988). "Rapid toxicity assessment from estuarine ecosystems: a new
tandem in vitro testing approach." Environmental Toxicity and Chemistry 17(6): 1099-1106.
Jones, K.B., Riiters, K.H., Wickham, J.D., Tankersley, R.D., O'Neill, R.V., Chaloud, D.J., Smith, E.R. and
Neale, A.C. (1997). "An Ecological Assessment of the United States Mid-Atlantic Region".
EPA/600/E-97/130. U.S. Environmental Protection Agency, Office of Research and Development,
Washington, DC.
Karr, J.R. (1981). "Assessment of biotic integrity using fish communities". Fisheries 6(6): 21-27.
Karr, J.R. and E.W. Chu. (1999). Restoring Life in Running Waters, Better Biological Monitoring. Island
Press, Washington, DC.
Krebs, Charles J. (1989). Ecological Methodology. Harper Collins Publishers, New York. 360 pp.
Lauenstein, G.G. and A.Y. Cantillo, eds. (1993). "Sampling and analytical methods of the National
Status and Trends Program National Benthic Surveillance and Mussel Watch Projects 1984-1992:
Comprehensive descriptions of trace organic analytical methods," Volume IV NOAA Technical
Memorandum NOS ORCA 71, Silver Spring, MD. 182 pp.
Long, E.R., MacDonald, D.D., Smith, S.L. and Calder, F.D. (1995). "Incidence of adverse biological
effects within ranges of chemical concentrations in marine and estuarine sediments." Environmental
Management 19(1): 81-97.
Long, E.R. and L.G. Morgan. (1990). "The potential for biological effects of sediment-sorbed
contaminants tested in the National Status and Trends Program." NOAA Tech. Memo NOS OMA 52.
National Oceanic and Atmospheric Administration, Seattle, WA. 175p.
Microbics Corporation. (1992). Microtox® Update Manual. Carlsbad, CA. 129p.
National Research Council. (2000). "Clean Coastal Waters: Understanding and Reducing the Effects
of Nutrient Pollution." Committee on the Causes and Management of Coastal Eutrophication Ocean
Studies Board and Water Science and Technology Board, Commission on Geosciences, Environment,
and Resources. National Academy Press, Washington, DC. 377 p.
Nixon, S.W. (1995). "Coastal marine eutrophication: A definition, social causes, and future concerns."
Ophelia 41: 199-219.
112
-------
Olsen, A.R. (1992). Program Data Quality Objectives for EMAP Status and Trends Draft Report. U.S.
Environmental Protection Agency, Environmental Research Laboratory, Corvallis, OR.
Olsen, A.R., Sedransk, J., Edwards, D., Gotway, C.A., Liggett, W., Rathbun, S., Reckhow, K.H. and
Young, L.J. (1999). "Statistical issues for monitoring ecological and natural resources in the United
States". Environmental Monitoring and Assessment 54: 1-45.
Overton, W.S. (1990). A Strategy for use of Found Samples. Department of Statistics, Oregon State
University, Corvallis, OR.
Overton, W.S., White, D. and Stevens, D.L. (1990). Design Report for EMAP. Office of Research and
Development, U.S. Environmental Protection Agency, Washington, DC 20460.
Overton, W.S. (1993). "Probability sampling and population inference in monitoring programs". In
Environmental Modeling with GIS. M.F. Goodchild, B.O. Parks and L.T. Steyaert (Ed.). Oxford
University Press, New York. 470-480 pp.
Overton, J.M., Young, T.C. and Overton, W.S. (1993). "Using 'found' data to augment a probability
sample: procedure and case study". Environmental Monitoring and Assessment 26(1): 65-83.
Paul, J.F., Scott, K.J., Holland, A.F., Weisberg, S.B., Summers, S.K., and Robertson, A. (1992). "The
estuarine component of USEPA's Environmental and Assessment Program". Chemistry and Ecology
7:93-116.
Paul, J.F., Gentile, J.H., Scott, K.J., Schimmel, S.C., Campbell, D.E. and Latimer, RW. (1999).
"EMAP-Virginian Province Four-Year Assessment (1990-93)". EPA/620/R-99/004, Office of
Research and Development, U.S. Environmental Protection Agency, Washington, DC.
Paul, J.F. (2002). "Developing and applying an index of environmental integrity for the U.S. Mid-Atlantic
Region". In Press: Journal of Environmental Management.
Ringwood, A.H., DeLorenzo, M.E., Ross, P.E., Holland, A.F. (1997). "Interpretation of Microtox solid-
phase toxicity tests: The effects of sediment composition." Envir. Toxicol. Chem. 16: 1135-1140.
Shannon C.F. and Weaver, W. (1949). The mathematical theory of communication. University of Illinois
Press, Urbana. 117 pp.
Stehman, S.V. and W.S. Overton. (1994). "Environmental Sampling and Monitoring". In: Handbook of
Statistics. P. Patil and C.R. Rao (Eds.), Elsevier Science B.V. 12: 263-305.
Stevens, D.L. (1997). "Variable density grid-based sampling designs for continuous spatial populations".
Environmetrics 8: 167-195.
Strobel, C.J., Buffum, H.W., Benyi, S.J., Petrocelli, E.A., Reifsteck, D.R and Keith, D.J. (1995).
Statistical Summary: EMAP-Estuaries Virginian Province - 1990-1993. U.S. Environmental
Protection Agency, Office of Research and Development, Washington, DC 20460.
113
-------
Strobel, C.J. (1998). Environmental Monitoring and Assessment Program -Mid-Atlantic Integrated
Assessment. Estuaries Component, Field Operations and Safety Manual. U.S. EPA, Office of
Research and Development, NHEERL-AED, Narragansett, RI.
Strobel, C.J., Buffum, H.W., Benyi, S.J. and Paul, J.F. (1999). "Environmental Monitoring and Assessment
Program: current status of Virginian Province (U.S.) estuaries". Environmental Monitoring and
Assessment 56: 1-25.
Summers, J.K., Macauley, J.M., Engle, V.D., Brooks, G.T, Heitmuller, P.T., Adams, A.M. (1993).
"Louisianian Province demonstration report: EMAP-Estuaries 1991". EPA/620/R-94/001. U.S.
Environmental Protection Agency, Office of Research and Development, Environmental Research
Laboratory, Gulf Breeze, FL. 161 p.
Summers, J.K., Paul, J.F., Robertson, A. (1995). "Monitoring the ecological condition of estuaries in the
United States". Toxicological and Environmental Chemistry 49(1-2): 3-108.
Swartz, R.C., DeBen, W.A., Jones, J.K.P., Lamberson, J.O. and Cole, F.A. (1985). "Phoxocephalid
amphipod bioassay for marine sediment toxicity". In Aquatic Toxicology and Hazard Assessment:
Seventh Symposium, ASTM STP 854. RD. Cardwell, R Purdy, and R.C. Bahner (Eds.). American
Society for Testing and Materials, Philadelphia, PA. 284-307 pp.
U.S. Environmental Protection Agency. (1991). "Draft analytical method for determination of acid
volatile sulfide in sediment." EPA/821/R-91/100. U.S. Environmental Protection Agency, Office of
Water, Washington, DC. 20 pp.
USEPA. (1994). "Methods for assessing the toxicity of sediment-associated contaminants with estuarine
and marine amphipods". EPA 600/R-94/025. U.S. Environmental Protection Agency, Office of
Research and Development, Narragansett, RI.
USEPA. (1995). "EMAP-Estuaries Laboratory Methods Manual, Volume I -Biological and Physical
Analyses". EPA/620/R-95/008. U.S. Environmental Protection Agency, Office of Research and
Development, National Health and Environmental Effects Research Laboratory, Atlantic Ecology
Division, Narragansett, RI.
USEPA. (1998). "Condition of the Mid-Atlantic Estuaries". EPA 600-R-98-147. U.S. Environmental
Protection Agency, Office of Research and Development, Washington, DC.
USEPA. (2000a). "Mid-Atlantic Highlands State of the Streams". Draft Final Report. EPA 620-R-99-002.
U.S. Environmental Protection Agency, Office of Research and Development, Washington, DC.
USEPA. (2000b). "Ambient aquatic life water quality criteria for dissolved oxygen (saltwater): Cape
Cod to Cape Hatteras". EPA-822-R-00-012. U.S. Environmental Protection Agency, Office of Water,
Washington, DC.
USEPA. (2000c). "Guidance for assessing chemical contaminant data for use in fish advisories (Vol. 2):
Risk assessment and fish consumption limits (Third edition)." EPA 823-B-00-008. U.S.
Environmental Protection Agency, Office of Water, Washington, DC.
114
-------
USEPA. (2001). Draft Report: Nutrient Criteria Technical Guidance Manual: Estuarine and Coastal Water.
EPA-822-B-01-003. U.S. Environmental Protection Agency, Office of Water, Washington, DC.
Valette-Silver, N. (1992). "Elemental Analyses in Marine Sediments and Biological Tissues. Quality
Assurance Program: Summary 1985-1990". NOAA Technical Memorandum NOS ORCA 66.
National Oceanic and Atmospheric Administration, National Ocean Service, Office of Ocean
Resources Conservation and Assessment, Rockville, MD.
Vernberg, F.S. (1972). "Dissolved gases". In: Marine Ecology, Vol. 1, Part 3. O. Kinne (ed.) Wiley-
Interscience, New York. 1491-1526 pp.
Weisberg, S.B., Frithsen, J.B., Holland, A.F., Paul, J.F., Scott, K.J., Summers, J.K., Wilson, H.T., Valente,
R.M., Heimbuch, D.G., Gerritsen, J., Schimmel, S.C., Latimer, RW. (1993). "Environmental
Monitoring and Assessment Program. EMAP-Estuaries Virginian Province 1990 Demonstration
Project Report". EPA/620/R-9'3/006. U.S. Environmental Protection Agency, Office of Research and
Development, Environmental Research Laboratory. Narragansett, RI.
115
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