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Bioavailability Assessment of a Contaminated Field Sediment from Patrick Bayou, Texas, USA: Toxicity Identification Evaluation and Equilibrium Partitioning
Citation:
Perron, M., R. M. BURGESS, K. T. HO, M. C. PELLETIER, M. G. CANTWELL, AND J. P. Shine. Bioavailability Assessment of a Contaminated Field Sediment from Patrick Bayou, Texas, USA: Toxicity Identification Evaluation and Equilibrium Partitioning. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY. Society of Environmental Toxicology and Chemistry, Pensacola, FL, 29(3):742-750, (2010).
Impact/Purpose:
In this study, contaminated sediments from Patrick Bayou, Texas were subjected to initial toxicity testing with the mysid, Americamysis bahia, and the amphipod, Ampelisca abdita. Sediment from one site (PB6A) was then evaluated with a marine whole sediment Phase I toxicity identification evaluation (TIE) and bioavailability assessments using equilibrium partitioning (EqP) approaches. Using a combination of TIE and EqP assessment tools, this investigation was capable of identifying nonionic organic contaminants (NOCs) as the likely class of contaminants causing acute toxicity to amphipods exposed to Patrick Bayou sediment. The cause of mysid toxicity was not definitively determined, but unmeasured NOCs are suspected.
Description:
Contaminated sediments are commonly found in urbanized harbors. At sufficiently high contaminant levels, sediments can cause toxicity to aquatic organisms and impair benthic communities. As a result, remediation is necessary and diagnosing the cause of sediment toxicity becomes imperative. In the present study, six sediments from a highly industrialized area in Patrick Bayou, Texas (USA) were subjected to initial toxicity testing with the mysid, Americamysis bahia, and the amphipod, Ampelisca abdita. All sediments were toxic to the amphipods, while sites PB4A, PB6A and PB9 were the only sites toxic to mysids. Due to its toxicity to both test organisms, site PB6A was chosen for a marine whole sediment Phase I toxicity identification evaluation (TIE). Results of the TIE found toxicity to amphipods was primarily due to nonionic organic contaminants (NOCs), rather than cationic metals or ammonia. Causes of mysid toxicity in the TIE were less clear. An assessment of metal bioavailability using equilibrium partitioning (EqP) approaches supported the results of the TIE that cationic metals were not responsible for observed toxicity in PB6A for either organism. Toxic units (TU) calculated on measured concentrations of NOCs in the sediment yielded a total TU of 1.25, indicating these contaminants are contributing to the observed sediment toxicity. Using a combination of these TIE and EqP assessment tools, this investigation was capable of identifying NOCs as the likely class of contaminants causing acute toxicity to amphipods exposed to Patrick Bayou sediment. The cause of mysid toxicity was not definitively determined, but unmeasured NOCs are suspected. Key words: sediment toxicity, toxicity identification evaluation, bioavailability, equilibrium partitioning