DISTRIBUTION OF METALS AND ACCUMULATION OF LEAD BY DIFFERENT TISSUES IN THE FRESH-WATER SNAIL LYMNAEA-STAGNALIS (L)

The concentrations of several metals in different body tissues of the freshwater snail Lymnaea stagnalis (L.), collected from an uncontamina ted environment, were measured by electron probe X-ray microanalysis. Significant concentrations of the potentially toxic elements manganese , titanium, and copper were detected in all tissues, although they wer e not detectable in the water sampled at collection; bioaccumulation i s thus evidenced. Highest concentrations of manganese and copper were present in the shell, while highest concentrations of titanium were pr esent in the head and foot. Experimental snails were continuously expo sed to lead chloride (lead at 5 ppm) for an experimental period of 3 w eeks. Both elements were accumulated to different extents by the snail tissues but with high concentrations again in the head of the animals , and chloride also in the visceral hump. No significant alterations i n the distribution of the other elements measured were observed in the lead chloride-exposed animals.