Comparison of Porewater and Elutriate Bivalve Larval Development Toxicity Testing in a Sediment Quality Triad Framework

Download or read book Comparison of Porewater and Elutriate Bivalve Larval Development Toxicity Testing in a Sediment Quality Triad Framework written by Blair Gordon McDonald and published by . This book was released on 2003 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The magnitude and extent of contaminated marine sediment are frequently assessed using a Sediment Quality Triad framework involving multiple toxicity tests using a variety of species, toxicological endpoints and exposure systems. Data are integrated into an overall assessment of sediment quality using a weight of evidence approach. Guidance on the selection of appropriate toxicity tests recommends a wide range of organism type, life-cycle, exposure route, and feeding type be included - porewater bivalve larval development tests increases the number of exposure routes under consideration. Interpretation of porewater toxicity data are subject to limitations, in part, related to the extensive chemical manipulations associated with the extraction of in situ anoxic porewater and the subsequent aeration required for the laboratory-based toxicity test. The ability of the porewater-only test to represent ecologically relevant adverse effects in the field appears minimal. Results from concurrent porewater and elutriate toxicity testing using newly fertilized larvae of the bivalve, Mytilus galloprovincialis are provided to illustrate these problems. Porewater samples were consistently more toxic than the corresponding elutriate sample, and ammonia, a common confounding factor in sediment toxicology, was identified as the most likely toxic agent for the majority of samples. Porewater toxicity testing using M. galloprovincialis is therefore not recommended as a routine element of the sediment quality triad unless additional chemistry (samples used for testing as well as in situ) are available to facilitate an appropriate interpretation of the resulting toxicity data.