Differential toxicity of three PCB congeners in developing sea urchin embryos and implication of TEQ approach
- Univ. of California, Los Angeles, CA (United States)
- Occidental Coll., Los Angeles, CA (United States)
- Southern California Coastal Water Research Project, Westminster, CA (United States)
The relationship between body burden and toxicity of three individual PCB congeners in developing sea urchin embryos was investigated to evaluate the validity of current predictive models of PCB toxicity in an invertebrate system. The uptake and accumulation of radiolabeled PCB congeners from sea water was measured in the sea urchin embryo tissues and the relative toxicity determined. According to the toxic equivalents (TEQ) approach of assessing risk to mammals, congener 77, a nonortho-substituted congener, is predicted to be more toxic than the diortho-substituted congeners 47 and 153. Using a 72 hour embryo development assay, congener 47 was found to be at least four times as toxic as congener 77, with EC50s of 15.7 and > 72.5 mmol/kg, respectively. Congener 153, a hexachlorobiphenyl, was virtually nontoxic even at the highest dose used. Cytologic and cytogenetic anomalies were studied to find a possibly more sensitive endpoint and to suggest a mechanism of toxicity. The cytogenetic analysis revealed that the PCBs inhibited mitosis. At the highest doses, complete mitotic arrest was observed. Congener 77 was found to be at least two times more toxic than congener 153 but not as toxic as congener 47 using mitotic activity as the endpoint. Thus, the two endpoints of toxicity did not change the order in which the congeners are toxic, but established different EC50s. The relative toxicities of these congeners in this study contradict the structure-activity prediction of the mammalian-based TEQ approach.
- OSTI ID:
- 458330
- Report Number(s):
- CONF-961149-; TRN: IM9717%%116
- Resource Relation:
- Conference: 17. annual meeting of the Society of Environmental Toxicology and Chemistry: partnerships for the environment - science, education, and policy, Washington, DC (United States), 17-21 Nov 1996; Other Information: PBD: 1995; Related Information: Is Part Of SETAC 17. annual meeting -- Abstract book. Partnerships for the environment: Science, education, and policy; PB: 378 p.
- Country of Publication:
- United States
- Language:
- English
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