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SOURCES AND USES Metallic tin is derived mainly from the mineral cassiterite (SnO ) and to a lesser extent from the sulphide ore stannite Cu S•FeS•SnS , althouih it can be derived from rarer minerals such as malayaite, 2CaSnSi0 2(Blunden et al. 1985). Tin is one of the earliest metals known and has5influenced our life style through the ages. Tin alloy artifacts dating from about 5,000 years ago have been unearthed at Ur, the site of ancient Babylonia (Zuckerman et al. 1978). Today we are exposed to tin on a daily basis through the use of tinplated food cans; of alloys such as pewter, bronze, brass, and solder; and from toothpaste containing stannous flouride (Zuckerman et al. 1978). Inorganic tin compounds are also used in a variety of industrial processes such as the strengthening of glass, as a base for colors, as catalysts in various chemical reactions, as stabilizers in perfumes and soaps, and as dental anticariogenic agents (WHO 1980). Organotin use is increasing rapidly in antifouling marine paints, in molluscicides, and in agriculture, which often causes serious adverse effects on nontarget biota. In 1975, the total world tin production was 236,000 tons, of which 72% was produced by China (10%), Indonesia (8%), Malaysia (35%), Thailand (7%), and 6% each by the UK and USSR (WHO 1980). The world production of recycled tin was about 20,000 tons, of which France produced about half (WHO 1980). The production and consumption of tin chemicals, especially organotins, has increased markedly in the past several decades (Table 2). The United States is the major consumer of tin and organotin compounds, followed by Japan, the UK, Germany, and France (WHO 1980). In 1976, for example, the United States consumed 11,000 tons of organotins, or about 39% of the world organotin production (Chau et al. 1984). The projected total demand for primary tin up to the year 2000 is estimated at 7.5 million tons. Total reserves currently are about 6.5 million tons; however, it is likely that new discoveries and increases in known reserves will result in sufficient new tin to meet the demand for this period (WHO 1980). The uses of inorganic and organotin compounds are numerous and increasing (Table 3). Industrial consumption of organotins, for example, rose from about 5,000 tons in 1965 to about 35,000 tons in 1980. At present, the uses of nontoxic organotin compounds (R2SnX2 and RSnX3 types) account for about 67% of 12