SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE

In the EU, a total of 12 779 tonnes of inorganic tin in 2001 was used in the production of the various organotin compounds, as well as in the production of inorganic tin compounds. It should be further noted that the above tonnage applies only to butyltin and octyltin compounds methyltin compounds, while used in the EU, are produced only outside the EU and are imported. 

A wide range of organotin compounds can be manufactured and placed on the market. Commercially used organotins are characterized by the number of organic groups in the compound. Tetrasubstituted compounds 

Sn -I- 2RI R2Snl2 (where R is the alkyl group and I is the anion). Methyltin stabilizers are produced by direct synthesis in the United States. Dibutyltin dichloride is manufactured from crude tetrabutyltin and tin tetrachloride and is usually catalysed with aluminium trichloride (Blunden Evans, 1989 Gaver, 1997 Thoonen et al, 2001). 

Data from ORTEPA (2002) (biocides, pesticides, synthesis, and giass coating), ESPA (2002) (PVC stabiiizers), and ETiCA (2002) (cataiysts), as updated by ETiNSA (2003). Exciudes use as a biocide in antifouiing paints, which was estimated at over 1250 tonnes per year (but is rapidiy deciining as the internationai ban is impiemented). 

The production figure for organotin PVC stabilizer in 1996-1998 in Japan was 6983-8649 tonnes per year (Chemical Daily Co., Ltd, 1999, as communicated to the Final Review Board by Dr J. Sekizawa). 

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