Organochlorine residue levels in Mississippi River water snakes in southern Louisiana [Indicators of persistence and biological magnification of pollutants]

Two species of water snakes, Nerodia rhombifera and Nerodia cyclopion, were taken from three locations along the Mississippi river to determine their value in pollution monitoring. Methods used for tissue analysis are described and results tabulated. The highest concentrations of organochlorine compounds were detected in the fat bodies , intermediate levels in liver and lowest concentrations in muscle tissue. No correlation between organochlorine load and sex, length or weight was found. Significantly increased levels of hexachlorobenzene in snakes from the Belle Helene location, where contamination is known to be high, indicates the possible value of these snakes in pollution monitoring.