implications of aquatic disposal of coal combustion residues in the United
States: A review
L. Rowe1, William A. Hopkins2, and Justin D. Congdon2
of Maryland Center for Environmental Science, Chesapeake BiologicalLaboratory,
Solomons, Maryland, U.S.A.
2University of Georgia, Savannah River Ecology Laboratory,
Aiken, South Carolina, U.S.A.
We provide an overview of research related to environmental effects of
disposal of coal combustion residues (CCR) in sites in the United States.
Our focus is on aspects of CCR that have the potential to negatively influence
aquatic organisms and the health of aquatic ecosystems. We identify major
issues of concern, as well as areas in need of further investigation.
Intentional or accidental release of CCR into aquatic systems has generally
been associated with deleterious environmental effects. A large number
of metals and trace elements are present in CCR, some of which are rapidly
accumulated to high concentrations by aquatic organisms. Moreover, a variety
of biological responses have been observed in organisms following exposure
to and accumulation of CCR-related contaminants. In some vertebrates and
invertebrates, CCR exposure has led to numerous histopathological, behavioral,
and physiological (reproductive, energetic, and endocrinological) effects.
Fish kills and extirpation of some fish species have been associated with
CCR release, as have indirect effects on survival and growth of aquatic
animals mediated by changes in resource abundance or quality. Recovery
of CCR-impacted sites can be extremely slow due to continued cycling of
contaminants within the system, even in sites that only received CCR effluents
for short periods of time.
The literature synthesis reveals important considerations for future investigations
of CCR-impacted sites. Many studies have examined biological responses
to CCR with respect to Se concentrations and accumulation because of teratogenic
and reproductively toxic effects known to be associated with this element.
However, the complex mixture of metals and trace elements characteristic
of CCR suggests that biological assessments of many CCR-contaminated habitats
should examine a variety of inorganic compounds in sediments, water, and
tissues before causation can be linked to individual CCR components. Most
evaluations of effects of CCR in aquatic environments have focused on
lentic systems and the populations of animals occupying them. Much less
is known about CCR effects in lotic systems, in which the contaminants
may be transported downstream, diluted or concentrated in downstream areas,
and accumulated by more transient species. Although some research has
examined accumulation and effects of contaminants on terrestrial and avian
species that visit CCR-impacted aquatic sites, more extensive research
is also needed in this area. Effects in terrestrial or semiaquatic species
range from accumulation and material trinsfer of elements to complete
recruitment failure, suggesting that CCR effects need to be examined both
within and outside of the aquatic habitats into which CCR is released.
Requiring special attention are waterfowl and amphibians that use CCR-containinated
sites during specific seasons or life stages and are highly dependent
on aquatic habitat quality during those periods.
Whether accidentally discharged into natural aquatic systems or present
in impoundments that attract wildlife, CCR appears to present significant
risks to aquatic and semiaquatic organisms. Effects may be as subtle as
changes in physiology or as drastic as extirpation of entire populations.
When examined as a whole, research on responses of aquatic organisms to
CCR suggests that reducing the use of disposal methods that include an
aquatic slurry phase may alleviate some environmental risks associated
with the waste products.
accumulation, aquatic animals, coal ash, electric power, energy, heavy
metals, sublethal effects, trace elements
L., W. A. Hopkins and J. D. Congdon. 2002. Ecotoxicological implications
of aquatic disposal of coal combustion residues in the United States:
A review. Environmental Monitoring and Assessment 80:207-276.
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