Tin contamination in Arcachon Bay: Effects on oyster shell anomalies

Abstract Total tin and organotin levels in both sea water and in oysters (C. gigas) from Arcachon Bay, and the frequency of shell anomalies have been monitored since the ban, in January 1982, of organotin compounds in antifouling paints. The results show that at the end of the survey period in November 1985, tin levels in areas of organotin input were 5 to 10 times lower than those found in 1982. The decrease in contamination of cultivated oysters has been particularly obvious since August 1984, when organotin concentrations found in oyster samples were less than 0.2 μg kg−1. The decrease in the incidence and extent of anomalies in calcification mechanisms in oysters (chambers) was particularly notable during this period and seemed to be correlated with the decrease in tin contamination of the waters of Arcachon Bay.