construction industry (flooring, fencing, and piping) and in the 

 food-packaging industry (bottles and f ilms) . Exposure of FVC to heat or 

 ultraviolet light for prolonged periods causes diminished optical clarity 

 and undesirable coloration. Stabilizers are required if the end products 

 containing FVC must be colorless or transparent, as in the case of 

 bottles, films, or sheets used for food packaging. In the 1970's, about 

 10 percent of all FVC being produced was stabilized with organotin 

 compounds. Following van der Kerk's discovery of the fungicidal 

 properties of organotin compounds and that these properties were dependent 

 upon the influence of the number and kind of organic groups bonded to tin, 

 many agricultural and industrial bactericidal and fungicidal uses have 

 been developed. Both triphenyltin hydroxide and triphenyltin acetate are 

 used to control fungi that cause potato blight (leaf spot) on sugar beets, 

 celery, carrots, onions and rice. Organotin compounds are also used as 

 fungicides to prevent tropical plant diseases in peanuts, pecans, coffee, 

 and cocoa. 



As an insecticide, triorganotin compounds have been used against 

 houseflies, cockroaches, mosquito larvae, cotton bollworms, and tobacco 

 budworms. They also act as chemosterilants and have antifeeding effects 

 on insects. 



In the early 1960 's, two organotin compounds (tributyltin oxide and 

 tributyltin fluoride) were first used as a molluscicides to kill several 

 species of freshwater snails that were the intermediate hosts of the worms 

 of the genus Schistosoma , which transmit the disease Schistosomiasis to 

 humans. This immediately led to the use of tributyltin (TBT) moiety as a 

 paint additive in 1961 for its biocidal properties in antifoulant boat 

 bottom paints. 



Tributyltin compounds used in antifouling paints are chemically 

 characterized by a tin (Sn) atom covalently bonded to three butyl 

 (C^Hg-) moieties. A representative TBT active ingredient, 

 tri-n-butyltin fluoride, may be chemically described by the following 

 structural formulas for the undissociated (neutral) pure form or the 

 active ingredient and for the water dissociated (positively charged) form. 



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