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WHAT IS CAUSING THE ACUTE AMPHIPOD TOXICITY OBSERVED IN FELD COLLECTED SAMPLES: AN INVESTIGATION USING EQUILIBRIUM PARTITIONING
Citation:
Berry, W J., R M. Burgess, F. J. Field, F. J. Keating, AND D R. Mount. WHAT IS CAUSING THE ACUTE AMPHIPOD TOXICITY OBSERVED IN FELD COLLECTED SAMPLES: AN INVESTIGATION USING EQUILIBRIUM PARTITIONING. Presented at Society of Environmental Toxicology and Chemistry Annual Meeting, Nashville, TN, November 12-16, 2000.
Description:
Equilibrium partitioning (EqP) provides an independent method of deriving chemical concentrations in sediments that should be causally related to sediment toxicity. In this study, EqP was applied using a toxic unit model to determine whether concentrations of chemicals commonly measured in sediment monitoring programs (cationic metals, PAHs, PCBs and other non-PAH narcotic chemicals, and pesticides) appear sufficient to explain observed toxicity. Where they are not, it may be inferred that unmeasured chemicals or measured chemicals not included in the toxic unit model are contributing to toxicity. Sediment chemistry and amphipod mortality data on 2954 sediment samples were extracted from a database which includes records from several large marine monitoring programs. A sample was considered toxic if the control-adjusted survival in a 10-day amphipod toxicity test was less than 80%. PAH toxic units were calculated using multipliers of 2.75 or 11.5 to account for unmeasured PAHs. Initial analyses suggest that in the 415 samples in which five simultaneously extracted metals (SEM) were measured, cationic metals were not commonly measured at concentrations expected to be toxic. SEM exceeded acid volatile sulfide (A VS) in a relatively small number of the samples. Very few samples in which SEM exceeded A VS were toxic, consistent with the low value of (SEM-A VS)/foc in these samples. Toxicity seemed to be more closely related to toxic units of PAHs in the 1,320 samples in which 13 commonly measured PAHs were measured. Among toxic samples, P AH thresholds were frequently exceeded. Further work will include the addition of more chemicals to the toxic unit model, and the use of more site and species- specific information.