Chromium, reproductive toxicity

Reproductive Toxicity. No data are available that impHcate either hexavalent or trivalent chromium compounds as reproductive toxins, unless exposure is by way of injection. The observed teratogenic effects of sodium dichromate(VI), chromic acid, and chromium (HI) chloride, adininistered by injection, as measured by dose-response relationships are close to the amount that would be lethal to the embryo, a common trait of many compounds (111). Reported teratogenic studies on hamsters (117,118), the mouse (119—121), and rabbits (122) have shown increased incidence of cleft palate, no effect, and testicular degeneration, respectively. Although the exposures for these experiments were provided by injections, in the final study (122) oral, inhalation, and dermal routes were also tried, and no testicular degeneration was found by these paths. 

A variety of reproductive effects including testicular effects, alterations in sexual behavior, and impaired fertility in females have been reported after high doses of chromium(VI) compounds." These effects, reproductive toxicity and testicular damage, were not replicated in a recent series of NTP studies in which mice and rats were exposed to 400 ppm in the diet." "... 

The results of animal studies therefore indicate that chromium(VI) and chromium(III) compounds are reproductive toxicants at high doses. Levels of chromium found in drinking water and food, however, are probably not high enough to elicit reproductive effects. 

Many studies have reported the effects of metals on general soil microbiological processes. Metals including cadmium, chromium, copper, lead, mercury, nickel, and zinc have been reported to inhibit many of the microbial processes listed above. Metal toxicity in the environment ultimately decreases litter decomposition, which can be measured by the rate of mass loss. Both copper (0.5 mg Cu g4 soil) and zinc (1.0 mg Zn g 1 soil) were shown to decrease the rate of decomposition of unpolluted Scots pine needle litter near a brass mill in Sweden.61 Duarte et al.63 also determined that copper and zinc toxicity reduced leaf decomposition rates and fungal reproduction. Other metals, such as cadmium, nickel, and lead, have also been reported to decrease litter decomposition.77... 

Trace metals (arsenic, cadmium, chromium, copper, nickel, lead, mercury, zinc) Industrial and municipal wastewaters runoff from urban areas and landfill erosion of contaminated soils and sediments atmospheric deposition Toxic effects including birth defects, reproductive failure, cancer, and systemic poisoning. 

No oral MRL has been derived for chromium(VI) or chromium(III) because a NOAEL for reproductive effects has not been adequately characterized. Additional studies are needed to identify a threshold for toxicity and establish dose-response relationships. However, any MRL derived for the oral route would have to take into consideration the essentiality of chromium. No dermal studies of intermediate duration in animals were located. The toxicity of intermediate-duration exposure to chromium compounds is relatively well characterized for the oral and inhalation routes. Dermal studies would be useful to determine possible target organs other than the skin. There are populations surrounding hazardous waste sites that might be exposed to the substance for similar durations. 

SAFETY PROFILE Poison by intravenous and intraperitoneal routes. Mildly toxic by ingestion. Experimental reproductive effects. A skin and eye irritant. See also n-BUTYL ALCOHOL and ALCOHOLS. Dangerous fire hazard when exposed to heat or flame. Auto-oxidizes to an explosive peroxide. Ignites on contact with chromium trioxide. To fight fire, use water spray, alcohol foam, CO2, dry chemical. Incompatible with oxidizing materials. 

OSHA PEL Cl 0.1 mg(Cr03)/m3 ACGIH TLV TWA 0.05 mg(Cr03)/m3 NIOSH REL (ChromiumCVT)) TWA 25 ig(Cr(VI))/m3 CL 50 ig/m3/15M SAFETY PROFILE Poison by skin contact, intraperitoneal, intravenous, subcutaneous, and intradermal routes. Experimental reproductive effects. Mutation data reported. A powerful oxidizer. When heated to decomposition it emits toxic fumes of Na20. See also CHROMIUM COMPOUNDS. 

The objective of this chapter is to put into perspective some of the current knowledge with respect to trace metals and their health implications. Potential adverse health effects of occupational exposures to trace metals are dis cussed cancer (arsenic, beryllium chromium nickel, and perhaps cadmium) chronic lung disease (beryllium and cadmium) neurologic and reproductive disorders (lead and mercury) and kidney disorders (lead and cadmium). Also discussed are the National Institute for Occupational Safety and Health (NIOSH) recommended standards for occupational exposure to several trace metals, the difficulty of establishing safe levels of exposure (particularly for carcinogens), and problems involved in identifying toxic components of trade name products. Special attention is given to the role of chemists to help protect the public health. 

Fly ash from municipal waste and industrial waste incinerators contains polychlorinated dibenzo-p-dioxins (PCDDs), including tetrachlorodibenzo-/j-dioxin (TCDD) and polychlorinated dibenzofurans (PCDFs), which are lipophiles, and heavy metals, including chromium, copper, manganese, vanadium, and lead, which are hydrophilesJ29-31 These chemicals have multiple toxicities and are known to impact the human liver, immune system, respiratory system, thyroid, male reproductive function, and CNS J32 34l Several are human carcinogensJ32 35 Enhanced toxic effects are observed in the mixtures of some of theseJ21,22 36 The mixtures of toxicants present in fly ash are complex and the mechanisms for their action on the human body are largely unknown. It is known that occupational exposure to fly... 

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