MP13 Aquatic Ecotoxicology
Monday, 14 November 2005: 8:00 AM - 6:30 PM in Exhibit Hall

(EVA-1116-000795) Are we underestimating the toxicity of hydrophobic organic contaminants to marine organisms?

Evans, A¹, Nipper, M¹, ¹ Texas A&M University-Corpus Christi, Corpus Christi, TX, USA

ABSTRACT- Hydrophobic organic contaminants (HOCs), including petroleum-derived organics (e.g., polycyclic aromatic hydrocarbons (PAHs) and alkanes) and organochlorines (e.g., polychlorinated biphenyls (PCBs) and chlorinated pesticides) enter the marine environment through industrial, urban and agricultural runoff and accumulate in the sediments. Methods for the measurement of sediment toxicity include porewater tests using sea urchin fertilization and embryological development assessments, and the copepod Schizopera knabeni 96-hour survival and nauplii hatching success test. In previous studies investigating the toxicity of sediments from Boston Harbor, it was determined that significant binding of contaminants to organic matter and particles led to insufficient evidence of the bioavailability of HOCs. It is hypothesized that excessive biomass in porewater toxicity testing systems prevents a critical mass of HOCs to be achieved and bioaccumulated, thus curbing toxic effects. Therefore, standard ecotoxicological methods for examination of the effects of HOCs of varying solubility are in question. In this study the toxicity of three categories of HOCs were assessed: a PAH (phenanthrene), an alkane (decane) and a chlorinated pesticide (lindane). The results of toxicity tests with these HOCs using different amounts of organisms (biomass) in the test system are under investigation using sea urchin early life stage tests. The additive effect of these HOCs, which are expected to exert a narcotic effect, in binary and trinary combinations is also under assessment with the same methods as well as with the copepod S. knabeni. The results are under investigation and will be discussed.

Key words: hydrophobic organic contaminant, toxicity test method, sea urchin, bioavailability