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|Title:||Determining steady-state tissue residues for invertebrates in contaminated sediment|
|Authors:||Kennedy, Alan James, 1976-|
Lotufo, Guilherme R.
Steevens, Jeffery A.
Bridges, Todd S.
|Publisher:||Environmental Laboratory (U.S.)|
Engineer Research and Development Center (U.S.)
|Series/Report no.:||ERDC/EL ; TR-10-2.|
|Abstract:||Abstract: Risk assessment of contaminated sediments often involves quantification of compounds in tissues via laboratory bioaccumulation exposures of benthic invertebrates. However, the standard 28-day exposure duration may not be adequately long for some compounds to reach steady state, defined as a stable concentration in exposed organisms. Steady-state tissue residues can be estimated using uptake and elimination rate constants. Experiments were conducted using two marine sediments from New York Harbor to assess bioaccumulation of PAHs, PCBs, chlorinated pesticides, dioxins, and Hg by sampling tissue during seven successive time points over an exposure of 56 days for the polychaete worm Nereis virens and 119 days for the clam Macoma nasuta. Exposure time required to attain steady state was organism and compound specific. Generally, N. virens tissues reached steady state more rapidly and accumulated higher contaminant residues. Nereis virens attained apparent steady state within roughly 28 days for PAHs, Hg, and most PCBs, but longer exposure was needed for some dioxins and pesticides. Steady state in M. nasuta was generally attained after 28 days of exposure for most compounds (sometimes after 100 days). Thus, some 28-day tissue residues may underestimate bioaccumulation and subsequently risk to benthos and higher trophic level organisms. The results of this study allow development of site-specific correction factors for estimating steady-state residues from 28-day exposures.|
|Appears in Collections:||Technical Report|
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