HC Deb 22 April 1985 vol 77 c369W
Mr. Viggers

asked the Minister of Agriculture, Fisheries and Food if he will list the species of shellfish or other marine life which, on the evidence available to his Department, are being adversely affected by the presence of tributyl-tin oxide in the natural environment.

Mr. MacGregor

The function of tributyl tin in marine antifouling paints is to kill all organisms which settle on the painted surface. Therefore, all such organisms in an estuary can be affected in this way, or by the TBT leached out of the paint. The evidence available from laboratory and field experiments indicates beyond reasonable doubt that the Pacific oyster is being adversely affected by concentrations of TBT currently present in some estuarine regions of the natural environment. It also strongly suggests that reproduction of the European flat oyster is adversely affected in these regions. It is extremely difficult to establish how many other species are being similarly affected. There is evidence that populations of some species have declined in recent years in estuaries which are known to contain concentrations of TBT at or about the parts per billion level. It is known that some species of algae and juvenile stages of marine molluscs, crustaceans and fish can be killed by short exposure in a laboratory to TBT concentrations in the parts per billion range; longer exposure to concentrations typical of those found in estuaries in which TBT can be detected is almost certain to be harmful to the sensitive stages of many marine species.

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