Molybdenum drinking water

It is clear that both the form of molybdenum administered and the route of exposure affect molybdenum metabolism and survival (Table 30.4). By comparison, adverse effects (some deaths) were noted at 250 mg Mo/kg body weight (BW) (in guinea pigs), at 50 mg/kg BW in domestic cats (central nervous system impairment), at 10 mg/L drinking water in mice (survival), at 10 to 15 mg total daily intake in humans (high incidence of gout-like disease), and at to 3 mg/m3 air in humans for 5 years (respiratory difficulties), or 6 to 19 mg/m3 in humans for 4 years (Table 30.4). 

Proposed criteria for human health protection include drinking water concentrations less than 50 pg Mo/L, and daily dietary intakes less than 7 pg Mo/kg food — based on a 70-kg adult (Table 30.5). Molybdenum concentrations in blood of healthy people averaged 14.7 pg Mo/L, distributed between the plasma and erythrocytes. Anemic people had significantly lower blood molybdenum levels. In leukemia patients, molybdenum levels increased significantly in whole blood and erythrocytes but not in plasma (Shamberger 1979). Additional work is recommended on the use of blood in fish and wildlife as an indicator of molybdenum stress and metabolism (Eisler 1989). 

Chappell, W.R., R.R. Meglen, R. Moure-Eraso, C.C. Solomons, T.A. Tsongas, P.A. Walravens, and P.W. Winston. 1979. Human Health Effects of Molybdenum in Drinking Water. U.S. Environ. Protection Agency Rep. 600/1-79-006. 101 pp. 

More than 15,000 analyses of waters, foods, plants, soils, and biological tissues have been analyzed as part of a research project on health effects of molybdenum. Results of this work will be used to prepare a drinking water criteria document for the U.S. Environmental Protection Agency. 

WHO has published guidelines for drinking water quality (WHO 1996, 1998), including values for antimony, arsenic, barium, cadmium, chromium, copper, lead, manganese, mercury, molybdenum, nickel, and... 

Worldwide, the molybdenum content of drinking water varies extremely in the range from <0.5 to >30pgLh Near industrial sources, such as molybdenum... 

Widjajakusuma etal. 1973). In rats, the addition of molybdenum at either 2 or 20 mgL drinking water inhibited esophageal and fore-stomach carcinogenesis (Luo etal. 1983). Further studies are necessary to replicate all these effects (Bogden et al. 

Aluminum, cyanide, molybdenum, nickel, silver, sodium, asbestos, and zinc are other inorganic chemicals that may contaminate drinking water supplies. The risks associated with these chemicals are relatively less either due to their rare occurrence in water or because the health risk associated with their presence is of limited concern. Nevertheless, government standards and the WHO guide values have been established for most of these chemicals. 

Natural molybdenum concentrations in ground and surface waters rarely exceed 20.0 xg/L significantly higher concentrations are probably due to industrial contamination. Existing wastewater and water treatment facilities remove less than 20% of the molybdenum accordingly, drinking water concentrations are near those of the untreated source. Molybdenum concentrations in saline waters appear to be directly related to salinity. In the Wadden Sea, for example, molybdenum concentrations were 0.08, 0.4, and 1.0p,g/L at salinities of 0.07,1.2, and 3.3%, respectively. 

The animals most sensitive to molybdenum insult are domestic mminants, especially cattle. Diets containing more than 15.0 mg Mo/kg dry weight and with a low copper to molybdenum ratio, or drinking water levels more than 10.0 mg Mo/L were frequently associated with molybdenosis in cattle. By contrast, adverse effects were documented in birds at dietary... 

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