Tin and its compounds

Toxicology. Inorganic tin and its compounds are generally of a low order of toxicity, largely because of the poor absorption and rapid excretion from the tissues of the metal (42—49). The acidity and alkalinity of their solutions make assessment of their parenteral toxicity difficult. The oral LD q values for selected inorganic tin compounds are Hsted in Table 2. It is estimated that the average U.S. daily intake of tin, which is mostly from processed foods, is 4 mg (see Food processing). 

Staff Forecast 91 Metals," Advanced Materials Processes, 24 (January 1991). Staff Various publications on tin and its compounds, including Tin and Its Uses (quarterly) Tin International (monthly) and statistical publications on tin (periodically), International Tin Research Institute, Middlesex, England. 

This Statement was prepared to give you information about tin and its compounds and to emphasize the human health effects that may result from exposure to it. The Environmental Protection Agency (EPA) has identified 1,300 sites on its National Priorities List (NPL). Tin has been found in at least 11 of these sites. However, we do not know how many of the 1,300 NPL sites have been evaluated for tin. As EPA evaluates more sites, the number of sites at which tin is found may change. This information is important for you to know because tin may cause harmful health effects and because these sites are potential or actual sources of human exposure to tin. 

Further information on the properties and uses of tin and its compounds and how they behave in the environment is found in Chapters 3, 4, and 5. 

Biomarkers of Exposure and Effect. Although tin and its compounds can be measured in tissues, blood, urine, and feces, it is difficult to quantitatively predict exposure levels from such determinations. 

Potentially high inhalation exposures to tin and its compounds may occur in the workplace or in agricultural uses of tin compounds. 

Winship KA. 1988. Toxicity of tin and its compounds. Adverse Drug React Acute Poisoning Rev 1 19-38. 

Tin and its compounds have some applications in the pharmaceutical industry. These include established uses in the fields of dentistry and veterinary medicine and, during the past decade, there have been additional developments in radiopharmacology and chemotherapy. 

In 1975, the estimated world aimual production of tin chemicals represented the consumption of 12,000—14,000 t of tin metal or 5% of total tin consumption (196). In 1978, ca 20,000 t/yr was consumed worldwide, with equal amounts represented by inorganic tin and organotin compounds (197). It is estabhshed that worldwide production of organotins rose from ca 50 t in 1950 to a possible 30,000—35,000 t in 1980. 

Many of the metals used by ancient man— coppei (cuprum, Cu), silver (argentum, Ag), gold (aurum, Au), tin (stannum, Sn), and lead (plumbum, Pb)—are in relatively short supply. Ancient man found deposits of the first three occurring as the elementary metals. These three may also be separated from their ores by relatively simple chemical processes. On the othei hand, aluminum and titanium, though abundant, are much more difficult to prepare from their ores. Fluorine is more abundant in the earth than chlorine but chlorine and its compounds are much more common—they are easier to prepare and easier to handle. However, as the best sources of the elements now common to us become depleted, we will have to turn to the elements that are now little used. 

It is the purpose of this chapter to summarize what is currently known about the stereochemistry and conformation of organogermanium, tin and lead compounds. Coverage is selective rather than exhaustive. The first section deals with compounds in which substitution by four different groups causes the metal atom to be stereogenic. We have limited our discussion to those cases in which at least three of the four substituents are alkyl or aryl. In this section we also briefly discuss pentacoordinated triorgano halostannanes. 

The United States is the major consumer of tin and organotin compounds, followed by Japan, the U.K., 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). 

Thermodynamic data for tin may be found in Tin and its Alloys and Compounds, B. T. K. Barry and C. J. Thwaits, Ellis Horwood, Chichester, 1983. The International Tin Research Institute has an informative Website at http //www.tintechnology.com, the library page of which is particularly good. 

Dermal contact with or ingestion of soil or sediments contaminated with tin or its compounds could be possible routes of exposure for people living near hazardous waste sites. Contaminated drinking water should not be regarded as an important route because tin compounds are generally not very water soluble. Stannous chloride is an exception. Likewise, tin compounds are not volatile, and inhalation exposure should not usually be a problem around waste sites. Ingestion of food or beverages from tin cans and occupational exposure appear to be the major potential sources of health concerns. 

Hematological Effects. No hematological effects have been observed in humans after inhalation, oral, or dermal exposure. Anemia was seen in rats exposed to repeated oral doses of both inorganic tin and organotin compounds. No such effects were observed in rats after inhalation or dermal exposure. It is unlikely that tin compounds would cause hematological effects in people in the vicinity of hazardous waste sites. 

Krigman MR, Silverman AP. 1984. General toxicology of tin and its organic compounds. Neurotoxicology 5 129-140. 

As in equation 91, destructive complexation of the dimeric hydroxide 581b with two equivalents of 1,10-phenanthroline or PI13PO produced, along with Me2SnO and H2O, the ionic complex 587 and the neutral compound 5881276. X-ray analysis showed that the cation of 587 (entry 11) has a severely distorted cis-octahedral C2N4 coordination arrangement around tin and it represents an example of a dicationic dichelate [R2Sn(L)2]2+ in order to adopt a cis structure (CSnC 108.4°). 

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