Coastal and Estuarine Risk Assessment - Chapter 13 docx

©2002 CRC Press LLC

Ecological Risk
Assessment in Coastal and
Estuarine Environments

Michael C. Newman, Robert C. Hale,
and Morris H. Roberts, Jr.

CONTENTS

13.1 Introduction
13.2 Chapter Contributions to Coastal and Estuarine Risk Assessment
13.3 Conclusion
References

13.1 INTRODUCTION

Hearing the rising tide, I think how it is pressing also against other shores I know …

— Rachel Carson

1

When Rachel Carson published

Silent Spring

,

2

she had already established her
reputation by authoring two popular books,

Under the Sea Wind

3

and

The Edge of
the Sea

.

1

This being the case, it is puzzling that

Silent Spring

, a book literally
changing how we view our relationship with our environment, contained so little
material about marine pollution. Such inconsistencies about marine environments
were commonplace at that time. At the same time that the last two books were
published, the first author spent many indolent hours as a child on a particular Long
Island Sound beach, alternately watching for dolphins on the horizon and, at the
sand’s edge, watching rats scurrying between the riprap in search of edible garbage.
Much more effort was spent scanning for surfacing dolphins than watching the rats
compete for garbage. Tar balls and rusty aerosol cans were as plentiful in the drift

zone as were skate egg cases and strings of whelk eggs. At one end of the beach
was a picturesque New England lighthouse silhouetted against plumes of smoke
rising above the Bridgeport city dump. Coastal pollution was as obvious as that in
nearby streams, lakes, and lands, but, for the coastal and estuarine habitats, the eye
13

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was drawn more to attractive, not degraded, seaside features. The tide of contami-
nation was similarly rising in other coastal environs but was viewed only peripherally.
We focused on the aesthetic and recreational pleasures of the coast. Although much
less apparent today, remnants of this tendency to ignore the evidence of degradation
exist in our activities.
What are the roots of this incongruity? A review of current U.S. environmental
legislation

4,5

indicates that a lack of legal mandates was not the reason. Ample
legislation included the overarching National Environmental Protection Act (1969);
Marine Mammal Protection Act (1972); Coastal Zone Management Act (1972);
Clean Water Act (1972); Federal Water Pollution Control Act (1977); Marine Pro-
tection Research and Sanctuaries Act (1972), especially Chapter 27 and amendments
in the Ocean Dumping Ban (1988); the Comprehensive Environmental Response,
Compensation and Liability Act (1980) as amended by the Superfund Amendments
and Reauthorization Act (1986), which established a risk assessment context; the
Organotin Antifouling Paint Control Act (1988); the Ocean Dumping Ban (1988);
and the Oil Pollution Act (1990). The need was equally obvious and legislative
initiatives were nearly as timely for stewardship for marine as for freshwater and
land resources.

Full consideration of coastal and estuarine pollution was delayed by cultural
biases. There were contrasting romantic and pragmatic delusions about the
oceans that delayed action as incisive as that made for freshwater and land
stewardship. Deeply embedded attitudes and complex use patterns regarding
marine resources made marine regulation more difficult. For example, conse-
quences of complex, traditional use patterns coupled with efficient modern
fishing gear are manifest in the current worldwide decline of marine fisheries.

6

In contrast to a complex of mores surrounding land ownership and obligations
associated with terrestrial landscapes, tradition associated with coastal resources
emerged more from the concept of the commons. Laissez-faire mores for com-
mons use resulted in a higher risk of degradation with coastal resources compared
with terrestrial resources.
Perhaps more importantly, our culture has consistently portrayed the ocean as
larger than humankind, a relationship reflected in innumerable literary works.
Humans might be overpowered by the seas, but not vice versa. This sense that the
ocean was too vast to be adversely impacted delayed rejection of “the solution to
pollution is dilution” paradigm for marine systems. One piece of evidence for this
mind-set was the relatively late passage of the Ocean Dumping Ban (1988) amend-
ment to the Marine Protection Research and Sanctuaries Act (1972).
Despite an initial delay, the capacity of coastal and estuarine environments to
absorb the cumulative loading of contaminants is now the focus of much insightful
research and effective action. Key aspects of marine pollution are being synthe-
sized; for example, see Reference 7. An entire issue of the leading journal,
Environmental Toxicology and Chemistry

(Vol. 20, No. 1, 2001) was recently
devoted to toxicant chemistry, effect, and risk assessment in marine and coastal

systems. (However, only one article in the journal issue addressed risk assessment.)
In the lead editorial, Scott

8

emphasized the importance of studying contaminants
in coastal systems:

©2002 CRC Press LLC
… [The coastal] zone represents 8% of the planet’s surface but is the source of 26%
of the world’s primary productivity. More than 76% of all commercially and recre-
ationally important fish and shellfish species are estuarine-dependent. Only recently
have these coastal areas been recognized as resource bases of national significance and
also among the nation’s most highly stressed natural systems.
… Historically, the focus of environmental toxicology and risk assessment has been
on rivers and lakes. The available dilution in near-coastal areas was thought to mitigate
adverse effects of anthropogenic contaminants. However, this perception has changed
because of constantly increasing population densities and scientific evidence of envi-
ronmental degradation. Approximately 44% of U.S. estuaries, assessed in 1998 for
environmental quality, were impaired.

The complexity of attitudes, uses, and stressors impinging on coastal and estu-
arine systems is now being confronted directly and fully. A recent issue of

Limnology
and Oceanography

(Vol. 44, No. 3, 1999) was dedicated to multiple stressors in
freshwater and marine ecosystems. Marine ecosystems discussed in that issue range
widely from southeastern U.S. estuaries and bays, northeastern U.S. harbors, and

coral reefs (Florida Keys reef system and Great Barrier Reef). Integrated coastal
planning and assessment activities are becoming more prominent (e.g., References
9 and 10), including those for acutely endangered systems such as coral reefs (e.g.,
References 11 and 12).
Despite recent progress, implementation of the ecological risk assessment par-
adigm to coastal and estuarine ecosystems still lags behind that for freshwater and
terrestrial systems. As an example, the excellent treatments of ecological risk assess-
ment written by Suter and colleagues

13,14

provide limited coverage of assessments
of coastal and estuarine systems. The U.S. EPA Guidelines for Ecological Risk
Assessment

15

requires considerable augmentation prior to optimal use for coastal
and estuarine systems. Enrichment of the ecological risk assessment paradigm is the
next crucial step in eliminating the differences in effective environmental stewardship
for marine, freshwater, and terrestrial environments. The chapters contained in this
edited book were developed with that goal in mind.

13.2 CHAPTER CONTRIBUTIONS TO COASTAL
AND ESTUARINE RISK ASSESSMENT

In this brief summary chapter, the preceding chapters will be placed into the context
of the current ecological risk assessment paradigm (see Chapter 1). The framework
for discussion will be Figure 1.1 (reproduced here) from Chapter 1 in which the
steps of ecological risk assessments are diagrammed.

The intent of Chapter 1 was to provide a context for ecological risk assessment
in estuarine and coastal regions, to describe major sources of information applicable
to risk assessments in these environments, and to highlight areas needing special
attention during assessments in marine systems. Strong and dynamic gradients, e.g.,
salinity and hydraulic flow, dominate the ecology and chemistry of these systems,
and their influence must be considered in estuarine risk assessments more than in

©2002 CRC Press LLC

other environments. By their nature, coastal and estuarine environments are transition
zones within landscapes. Risk assessments must fully consider relevant landscape
features, e.g., the contaminant loadings in river discharge into an estuary or the land
use around the estuary proper. Further, as is the case for all ecotones, crucial features

The ecological risk assessment paradigm as presented by the U.S. EPA (see Chapter 1 for
further detail).

©2002 CRC Press LLC

of coastal environments cannot be captured solely by envisioning them as ecosystems
existing between adjacent ecosystems. The ecotone framework may be equally, or
more, important than the ecosystem context underpinning problem formulation in
most ecological risk assessments.
Currently, several general methods are applied for identifying hazards in coastal
and estuarine systems, and these methods generate important information applicable
to risk assessments. Methods currently include water quality criteria generation,
sediment quality guidelines, and toxics characterization methods. While the criteria
and guidelines have utility for management, the tools of probabilistic risk assessment
can improve our ability to protect marine and other environmental resources.
The European, or more specifically European Union (EU), context for coastal

and estuarine risk assessments was explored in Chapter 2. Consequently, this
chapter covered all aspects of the risk assessment paradigm diagrammed in the
figure, but from a European perspective. After outlining the political institutions of
the EU, the authors discussed how environmental legislation is promulgated, a
process distinct from that in the United States. Under existing and developing
legislation, both prospective and retrospective risk assessment are primary tools
used in the management of hazardous chemicals. In both cases, the focus is the
hazard quotient approach, although probabilistic risk assessment approaches are
being evaluated for incorporation into future directives. At present, difficulties
arising from incomplete information regarding existing and new chemicals are
acknowledged as the reason for delay in actual management of many chemicals
even when impacts of their use are apparent. In the EU, no action is taken to regulate
a material until the risk assessment is complete. Many people conclude from the
resulting conundrum that the EU should apply the controversial Precautionary
Principle, that is, to take regulatory action to prevent present or possible impacts
while the risk assessment proceeds.
Reflecting the theme discussed in the introduction to this chapter, the predom-
inant freshwater focus was acknowledged for risk assessment and discussed in the
context of using the more abundant data for freshwater species to predict conse-
quences to saltwater species. The EU approach to saltwater assessments is described
in detail, including current shortcomings. The use of freshwater species data to
predict risks to saltwater species is a significant shortcoming that applies not only
to the EU but also to the United States (see Chapter 1). To change the current practice
effectively will require substantially more data for marine species.
The authors of Chapter 3 addressed emerging contaminants of concern and
provided examples of several classes. They discussed chemicals underemphasized
in current research, legislation, and risk assessments and those that may elicit
inadequately studied effects, such as endocrine disruption discussed in Chapter 8.
Their treatment here contributes directly to the “problem formulation” and “exposure
analysis” components of the risk assessment paradigm (see the figure). Emphasis

was on assuring that these important contaminants are more fully considered in
assessments of multiple stressors in freshwater, estuarine, and coastal environments.
Emerging toxicants are those recently introduced in significant amounts, those
historically ignored in environmental regulation and risk assessment, and those being
applied now in new ways that require more careful scrutiny. Some priority pollutants

©2002 CRC Press LLC

such as polychlorinated biphenyls (PCBs) are considered here as well because new
knowledge has changed the context for considering their potential effects. Other
emergent toxicants included brominated fire retardants, natural and synthetic estro-
gens, alkylphenol polyethoxylates and related compounds, pharmaceutical agents,
antimicrobial agents, and chemicals in personal care products.
As one studies emerging toxicants, one is struck by the complexity of chemical
mixtures that exist in various environments. Chemical mixtures may have synergistic
or antagonistic effects that are inadequately considered in risk assessment because
of our poor understanding of interactions. This observation calls into question the
traditional chemical-by-chemical evaluation of environmental risk, also discussed
in Chapters 1 and 2. Biosolids, sewage sludge destined for land application, are
another interesting example of a complex stressor. Current regulation of these in the
United States is based on incomplete risk assessments that consider only a subset
of the contaminants present. For example, the nonylphenols and brominated diphenyl
ethers, although present in biosolids in milligram per kilogram quantities, are not
considered. Different objectives in assessing resulting risks in the EU vs. the United
States also produce different conclusions. In the former, a “do no harm” approach
is taken toward contaminant accumulation in receiving soils and effects on soil
organisms. In the United States, the maximum allowable toxicant concentration
(MATC) for the protection of humans and livestock is the end point of concern. This
may relate to differing views of the environment with the perception in the United
States that resources are less limited, akin to our attitude toward the oceans expressed

earlier in this chapter.
Chapter 4 discussed the causal assessment at the center of every risk assessment.
It described inherent errors that emerge in informal methods used to generate pre-
liminary and definitive statements of cause and effect. Qualitative methods of assign-
ing causality were demonstrated with the example of notionally polycyclic aromatic
hydrocarbon (PAH)-induced hepatic cancers in fish from contaminated coastal envi-
ronments. The chapter then provided details of a formal, Bayesian approach that
minimizes the likelihood of a mistake in the assessment of causality. An example
was provided of quantitatively estimating the likelihood of a fish kill given the
presence of

Pfiesteria piscicida

or a related complex of marine dinoflagellates. This
chapter contributes especially to the problem formulation and risk characterization
stages of the risk assessment paradigm, but also to all the other components that
depend on identifying causal linkages between toxicants and effects.
Three chapters addressed key issues relevant to the “analysis phase” of the risk
assessment paradigm. Each chapter focused on a specific group of chemicals in the
context of speciation, bioavailability, and effects.
Chapter 5 provided details for both bioavailability and effects essential to the
analysis phase of risk assessment for organic compounds present in the marine
environment. Bioavailability from water, sediment, and food was discussed,
including models for quantifying uptake. Mechanisms of xenobiotic metabolism
and elimination were described. Considerable discussion was devoted to the mech-
anisms of contaminant transformation to readily excreted metabolites and the
adverse consequences occurring if a metabolite is more toxic or carcinogenic than
the parent compound.

©2002 CRC Press LLC

Chapter 6 emphasized bioavailability and bioaccumulation of metals, especially
those of ionic mercury and methylmercury. It contributed directly to exposure anal-
ysis (see the figure). The role of food chain transfer of metals from water to the
target organism was discussed specifically as it pertains to mercury, but the author
also discussed the role of this route for other metals. The author included a brief
discussion of how dissolved organic material, particulate organic material, and acid
volatile sulfides affect availability and uptake from water and sediment. The discus-
sion reviewed environmental speciation of metals and the role that speciation plays
in bioaccumulation and trophic transfer.
Chapter 7 expanded considerably on the theme of metal exposure and effects
to estuarine and coastal organisms. The theme of chemical speciation and its
relationship to accumulation of metals was extended in this chapter to a consid-
eration of how one uses this information in risk assessment to meet regulatory
requirements. This included discussion of applying equilibrium models such as
the Dynamic Multipathway Bioaccumulation Model (DYMBAM) to incorporate
dissolved and dietary sources of metals into predictions of bioaccumulation. This
chapter addressed many exposure and effects characterization issues of the analysis
phase of a risk assessment.
As discussed briefly in Chapter 3, the role of xenobiotics as endocrine-dis-
rupting agents is becoming a major area of effects research for marine organisms.
Chapter 8 dealt primarily with the ecological effects aspects of the analysis phase
of the risk assessment paradigm for endocrine-disrupting agents, an increasingly
important class of xenobiotics. The authors first summarized information about
modes of action and effects in marine fish and invertebrates. Many modes of action
and effects that were discussed for endocrine disruption extended discussions in
previous chapters that focused on biotransformation and clearance of chemicals
from tissues (Chapter 5) and emergent contaminants (Chapter 3). The authors then
extended the review to describe methods for generating a coherent risk assessment
strategy for endocrine disruptors with particular reference to marine organisms.

This is a new application of the risk assessment paradigm that is likely to bring
significant new issues to the discussion.
The focused assessment of risk to marine mammals was the topic of Chapter 9.
This chapter raised the issue of how to describe exposure (a major element in the
analysis phase of the risk assessments process) for cetaceans, pinnipeds, and mus-
telids. Most of these charismatic animals are not amenable to laboratory experimen-
tation and legal issues often preclude controlled experimental exposures. Much
discussion focused on determining toxicity reference values (TRVs) for persistent
organochlorine (POC) compounds. The ultimate intent was to determine exposure
dose to animals that cannot be readily sampled or subjected to experimental expo-
sure. The authors then reviewed literature related to effects on marine mammals,
noting that most studies were hampered by the sample size and life mode of these
species. Finally, data from New Zealand marine mammals were used as a case study
for a risk assessment. This risk analysis employed a hazard quotient approach that
used the exposure and effects parameters as estimated by the methods described
earlier in the chapter. The chapter thus addressed problem formulation and risk
characterization in addition to effects and exposure assessments, resulting in a

©2002 CRC Press LLC

general risk assessment for marine mammals exposed to POC compounds. However,
end points of concern other than those elicited by dioxin-like chemicals may be
important, e.g., the endocrine-disrupting agents discussed in Chapter 8.
The remaining chapters shifted focus from effects at the suborganismal and
individual levels to those at higher levels of biological organization. These three
chapters looked to a more comprehensive risk analysis addressing populations,
incorporating analyses of spatial and temporal heterogeneity.
Chapter 10 presented a matrix model for predicting demographic consequences
of chronic exposure to a pollutant. Data for a New Bedford Harbor (Massachusetts)
fish population (

Fundulus heteroclitus

) chronically exposed to PCBs were used as
a case study for model application. Interestingly, demographic projections from
toxicological evaluations of fish naive to PCBs predicted poor population status.
This prediction contrasted with the apparent robustness of the New Bedford Harbor
population. Compensatory shifts including those related to life history and physio-
logical adjustments were described that lead to increased potential for evolutionary
effects. The authors suggested that a paucity of demographic data for the well-studied
fish used in the case study contributed to the difficulty in deriving a retrospective
model that accurately predicted the condition of the population. The authors pro-
posed research at additional sites subject to different types of stressors to evaluate
further the applicability of the model and to seek improvements in its use. The
disparity between prediction and real populations raised the issue of dealing with
risk assessment in a multigenerational context to account for adaptation of resident
populations to the gradual introduction of contaminants that occurred historically.
Chapter 11 considered population-based risk assessment in a complex land-
scape. As mentioned above, such a landscape context can be essential in adequately
defining risk to coastal and estuarine species. Although the modeled heron popu-
lation described was lacustrine, the approach taken for this common coastal species
is directly applicable to landscapes encompassing marine features and pollution.
In this study, heron exposure to mercury was through their diet. A set of well-
known models for uptake by various routes was integrated with demographic
analysis. A metapopulation context for this analysis was developed using a Geo-
graphical Information System (GIS) analysis of habitat and then applied to pre-
dicting population consequences of exposure. Risk was estimated and placed into
the context of different metapopulation scenarios including the presence of sig-
nificant migration to compensate for excess mortality or depressed reproductive
success. Important features of this population-level study were its spatially and

demographically explicit structure.
There was a similar landscape context for Chapter 12 that included an explicit
recognition of the ultimate use of any risk assessment, i.e., risk management to
reduce risk as suggested in Chapters 1 and 2. The potential or known incremental
chemical risks for a highly modified urban estuary were emphasized in this chapter.
The authors discussed the implications that apply to any implementation of risk
management; one must understand that the human activities producing environmen-
tal risk, especially in urban areas, are an unchangeable and persistent feature of the
landscape that must be addressed in any risk assessment. This issue was alluded to
in several earlier chapters.

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The analysis stage of risk assessment was developed in a context described by
the authors as an “ecological coincidence analysis.” This approach is one that
assumes cause-and-effect relationships rather than attempting to demonstrate them.
The distribution of stressors was compared to that of receptors to determine the
extent of co-occurrence. Ecological coincidence was the central theme in their
analysis and was based on the notion that there can be no effect if there is no co-
occurrence. To demonstrate this principle, the authors used three U.S. examples
including the Passaic River estuary in New Jersey, the Fox River lacustuary of Lake
Michigan (Wisconsin), and the New York Harbor. Here, coincidence in both time
and space was essential to the analysis. The ultimate result of such analyses was an
estimate of time-dependent and site-specific dose for the exposure analysis. In the
examples, specific estuarine considerations are included such as restriction of avian
foraging on tidal flats to periods of low tide. Thus, differential exposure in time is
not only a matter of historical (an issue raised in Chapter 10) and seasonal differences
in spatial distribution of a receptor, but also differences on tidal scales. In the analysis,
the potential for behaviorally mediated reduction in exposure was discussed. As in
the preceding chapter, GIS methodologies played an important role in the analysis

phase of the risk assessment process. Although the importance of stressor and
receptor coincidence in time and space is not new, the use of the concept as a central
element in specific estuarine landscape risk assessments brought the implications of
the concept into sharper focus.

13.3 CONCLUSION

The intent in developing this book was to accelerate the application of ecological
risk assessment in coastal and estuarine systems. Despite the need for such assess-
ments, the development of methods applicable to these systems has lagged behind
those for freshwater and terrestrial systems. Coastal and estuarine environments
have features unique or extreme relative to other environments; therefore, this
special attention to risk assessment in these habitats is necessary. These tend to
be environments with high risk of adverse impacts stemming from increasing and
complex uses by humans. Assessment is particularly difficult due to the inherent
complexity of these landscape features and the complex of human activities occur-
ring within them.
Each chapter provides information about or examples of applying the current
ecological risk assessment paradigm to these unique and vulnerable environ-
ments. Collectively, the authors suggest future directions that assessors can and
should pursue.
The authors in this book did not address risks to certain, highly valued habitats
such as coral reefs or areas of low human population density such as coastal
agricultural areas. Also, little attention was been given to the effects of contaminants
on primary producers except relative to toxicant entry into the food chain. In this
book, attention to estuarine or marine communities was limited. As we look to the
future, these and other issues not included here must be given careful consideration
in problem formulation, analysis, and, ultimately, risk characterization. Our risk
assessments are never definitive, and the benefits of our risk management are always

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uncertain without consideration of the full diversity of biological organization and
stressor exposure.
This may lend additional support for the Precautionary Principle, already gaining
acceptance in the EU (Chapter 2). As we have learned in recent decades, the old
paradigm is flawed that the sea exceeds our ability to decimate it. Even as we hasten
to develop and implement new paradigms for environmental management to benefit
the oceans, our industrial society is changing the environment without adequate
attention to the preservation of vital resources.
For our children and grandchildren to also enjoy indolent moments along estu-
arine and coastal shores, either appropriate risk-based paradigms for reasoned action
must be formulated or we must apply precautionary measures. It is our hope that
the contents of this book will help in some small but meaningful way to convey the
need for solutions to the problems emerging from our use of the coastal resource.

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Silent Spring

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Under the Sea Wind

, Oxford University Press, New York, 1941.
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Environ. Toxicol. Chem.,

20, 115, 2001.
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Federal Environmental Laws

, 2000 Edition, WEST Group, Eagan, MN.
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Fisheries

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Practical Handbook of Estuarine and Marine Pollution

, CRC Press,
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, WIT Press, Boston, 2000.
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, IUCN (International Union
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Reefs at Risk

, IUCN (International Union for Conservation of Nature
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Ecological Risk Assessment

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., Ecological
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