HA1 Contaminated Harbour and River Sediment
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() Urban harbor sediment contaminants responsible for acute toxicity in tests with Ampelisca abdita.

Brownawell, B1, Dick, J1, McElroy, A1, LeBlanc, L1, Ruggieri, J1, Cottrel, L1, Reddy, C2, 1 Stony Brook University, Marine Sciences Research Center, Stony Brook, NY, USA2 Woods Hole Oceanographic Institution, Woods Hole, MA, USA

ABSTRACT- Whole organism toxicity tests are one of the means in which sediments are assessed for risks associated with chemical contaminants. In urban harbor settings, decisions associated with dredged material management are affected greatly by the high percentages of sediments that fail acute toxicity tests with various amphipod species. In the waterways surrounding the metropolitan region of New York and New Jersey over half of the sediments in need of dredging are toxic to the amphipod Ampelisca abdita. A variety of approaches have been utilized to identify the agents causing the observed toxicity and most results point to the likely importance of relatively nonpolar organic contaminants in controlling acute toxicity. PAHs play a significant role in causing acute narcosis-based toxicity in short-term tests. However, direct measurement of amphipod body residues as well as predicted body residues based upon sediment concentration typically can only account for 1–10 % of the levels corresponding to an LC50 for A. abdita. We have analyzed sediments samples collected by EPA in recent basin-wide assessments of sediment quality for two other classes of potential toxicants: neutral alkylphenol ethoxylate metabolites (APEMs) and the semivolatile mixture of petroleum hydrocarbons generally termed the unresolved complex mixture (UCM). Sediment APEM levels are as high as 135 g/g and predicted APEM body burdens are 1–8% of narcosis-based critical body residues determined experimentally. Concentrations of UCM are much higher (up to 7100 g/g) and the relationship between amphipod mortality and organic carbon normalized levels of UCM are consistent (if narcosis-based critical body residues and biota sediment accumulation factors are similar to that of PAHs) with petroleum hydrocarbons being the primary cause of mortality in the New York/New Jersey Harbor basin. For sediments with comparable organic carbon normalized levels of UCM, those with greater abundance of lower molecular weight (and more easily desorbed) hydrocarbons were gnerally more toxic.–

Key words: sediment toxicity, hydrocarbons, narcosis

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