Levels And Toxicities Of Selected Inorganic And Organic Contaminants In A Swamp Environment

Field and laboratory studies were conducted to determine the levels of cadmium, lead and hexachlorobutadiene, HCBD, in various samples collected from a swamp environment in Louisiana, and to assess the toxicities of arsenic, cadmium and mercury to two species of aquatic organisms (bluegills and crawfish) indigenous to this swamp. Cadmium and lead were present in almost all collected samples. Their concentrations in fish were below the action levels set by EPA for the protection of human health. However, hazardous levels of these two metals were found in samples of crawfish, vegetation, soil, sediment and water to some extend. Low levels of HCBD were recorded in water and sediment samples. In bioassay studies, mercury was found to be the most toxic metal, while arsenic was the least toxic. Between the two test organisms, bluegills appeared to be more sensitive than crawfish. Mixtures of cadmium with arsenic or mercury resulted in a combined toxic effect which was simply additive. However, a synergistic effect was recorded with the mixture of arsenic and mercury.