Exposure-Pathway Models Explain Causality in Whole-Sediment Toxicity Tests
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- 作者：Stuart L. Simpson and Catherine K. King
- 刊名：Environmental Science & Technology
- 出版年：2005
- 出版时间：February 1, 2005
- 年：2005
- 卷：39
- 期：3
- 页码：837 - 843
- 全文大小：339K
- 年卷期：v.39,no.3(February 1, 2005)
- ISSN：1520-5851
文摘
Measurements of lethal effect concentrations (LC50) andbioaccumulation following water-only and whole-sedimentexposures of the amphipod, Melita plumulosa, and thebivalve, Tellina deltoidalis, to copper, were combined withbioenergetic-based kinetic models of exposure pathwaysto explain causality in whole-sediment toxicity tests. For bothorganisms, lethal body concentrations (LBCs) weregreater for water-only exposures than for sedimentexposures and indicated that the rate of copper accumulationand/or the mode of toxicity of copper assimilated weredifferent for dissolved and particulate phases. Thenet assimilation of copper, expressed as a lethal exposureconcentration (LEC) that was independent of the postexposure copper efflux, was shown to better explain theobserved toxicity. The LEC of copper was the same for bothwater-only and whole-sediment toxicity tests. It ispredicted that, for each species, a large range of effectconcentrations may be measured for sediments having thesame total copper concentration. These are conditionaleffect concentrations, as their value will be determined bytotal copper concentrations, partitioning (Kd) relationships(sediment properties), organism physiology (uptakerates from waters, assimilation efficiencies from solids),and organism feeding behavior (feeding selectivity). Theimportance of these factors to the development of sedimentquality guidelines for metals based on species sensitivitydistributions is discussed.