Copper bioaccumulation and depuration by red swamp crayfish, Procambarus clarkii.

Abstract

Environmental contamination of copper occurs from two major sources: weathering and land-drainage. Mine production of Cu was estimated to be 307 million metric tons sometime ago (Nriagu et al 1979). A considerable amount of copper is contributed by the effluents of metal finishing industries to sewage sludge. Organic wastes of industrial and agricultural origin enter aquatic ecosystems and Cu may exist in ionic form or be complexed to organic and inorganic ligands. Generally, crustaceans accumulate some metals (including Cu) directly proportional to the increase in bioavailability from water and food-chains (Rainbow et al 1990). Many decapod crustaceans can regulate their tissue and body burdens of heavy metals effectively (Rainbow & White 1989). Red swamp crayfish of Louisiana, Procambarus clarkii occur naturally in road-side ditches, bayous, swamps, marshes and the Atchafalaya Basin, and support a multi-million dollar industry. Approximately 60% are collected naturally and 40% from commercial ponds (Huner and Barr 1984). Since humans are the primary consumers of crayfish, heavy metals in natural waters present a great potential for bioaccumulation and biomagnification through any simple food-chain.