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UPTAKE AND DEPURATION OF NON-IONIC ORGANIC CONTAMINANTS FROM SEDIMENT BY THE OLIGOCHAETE, LUMBRICULUS VARIEGATUS
Citation:
Ingersoll, C. G., E. L. Brunson, N. Wang, J. Dwyer, G T. Ankley, Mount, AND D. Mount. UPTAKE AND DEPURATION OF NON-IONIC ORGANIC CONTAMINANTS FROM SEDIMENT BY THE OLIGOCHAETE, LUMBRICULUS VARIEGATUS. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 22(3):872-875, (2003).
Description:
Uptake of sediment-associated contaminants by the oligochaete, Lumbriculus variegatus, was evaluated after 1,3,7,14,28, and 56 d of exposure to a field-collected sediment contaminated with DDT and its metabolites DDD and DDE or to a field-collected sediment contaminated with PAHs. Depuration of contaminants by oligochaetes in a control sediment or in water was also evaluated over a 7-d period after 28 d of exposure to the field-collected sediments. Accumulation of PAHs with a log octanol-water partitioning coefficient (log Kow) < 5.6 typically reached a peak at day 3 followed by a lower plateau between days 7 and 56 of the sediment exposure. Similarly, 4,4'-DDT exhibited a peak in accumulation at day 14 followed by a decline at days 28 and 56. In contrast, accumulation of PAHs with a log Kow > 5.6 or DDD and DDE typicallly exhibited a steady increase from d 1 to about d14 or 28 followed by a plateau. Therefore, exposures conducted for a minimum of 14 to 28 d better reflected steady-state concentrations for DDT and its metabolites and for PAHs. Depuration rates for DDT and its metabolites and high-Kow PAHs were much higher in organisms held in clean sediment relative to both water-only depuration and model predictions. This suggests that depuration in clean sediment may artificially accelerate depuration of hydrophobic compounds. Comparisons between laboratory-exposed L. variegatus and oligochaetes collected in the field from these sediments indicate that results of laboratory tests can be extrapolated to the field with a reasonable degree of certainty.