ABSTRACTPolychlorinated biphenyls in the environment may constitute a potential health hazard to edible fishery products, which are caught in polluted waters, and/or packaged in materials containing PCBs. Since many state and federal agencies are concerned with the toxicity of PCBs in seafoods, this project was designed to develop physical and chemical methods (ultraviolet radiation and treatment with sodium nitrite) for eliminating these compounds from shrimp. Shrimp were treated with 1 sodium nitrite solution followed by 100 ppm solution of Aroclor 1254 and Aroclor 1260, mixtures of PCB containing 54 and 60 chlorine respectively. A parallel experiment was performed without sodium nitrite pretreatment. All samples were analyzed after sun drying for 12, 24, 36 and 48 hr. PCBs were recovered by extraction, Florisil column cleanup and gas chromatography. Individual chlorinated biphenyls were identified by combined GC and MS. Complete reduction of PCBs was observed for both Aroclor 1254 and 1260 in sodium nitrite treated shrimp after 30 and 48 hr respectively. Untreated samples exhibited complete degradation after a lag of 6 and 12 hr respectively for each of the PCB mixtures. Pretreatment of shrimp with 1 sodium nitrite considerably accelerated the reduction of PCBs. The rate of reduction was dependent on the percentage chlorine content of the PCB. Sun drying induced a stepwise reductive dechlorination with higher chlorinated biphenyls breaking to lower chlorinated biphenyls. The complete phenomena of degradation was presumed to be either one or a combination of reductive dechlorination, polymerization and isomerization processes. Since sun drying is a common practice in many parts of the world, this process could eliminate or reduce toxic polychlorinated biphenyls from seafoods.
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