TOXICOLOGICAL PROFILE FOR CHROMIUM - Davidborowski.com

CHROMIUM 2322. HEALTH EFFECTSmentioned above, the reduction of chromium(VI) to chromium(III) by these various processes within thelungs serves as a natural defense mechanism by decreasing the amount of chromium absorbed andenhancing mucociliary clearance of chromium(III). Theoretically, further clearance from the lungs mightbe achieved by the administration of expectorants, but the efficacy of such a procedure has not beentested.Chromium(III) is also poorly absorbed by the gastrointestinal tract, and chromium(VI) is reduced tochromium(III) in the gastric environment, limiting the bioavailability of chromium(VI) (De Flora et al.1987a; Donaldson and Barreras 1966). Thus the oral toxicity of chromium metal is low. However,chromium(VI) compounds are highly corrosive to the gastrointestinal tract and can lead to hepatic, renal,hematological, and neurological effects (Clochesy 1984; Coogan et al. 1991a; Diaz-Mayans et al. 1986;Iserson et al. 1983; Kaufman et al. 1970; Kumar and Rana 1982, 1984; Samitz 1970; Saryan and Reedy1988). The reduction of chromium(VI) to chromium(III) in the stomach is greatly enhanced at low pHand shortly after meals due to increased gastric juice secretion (De Flora et al. 1987a). Therefore,administration of food might help decrease the gastrointestinal absorption of chromium. The enhancedreduction of chromium(VI) at low pH suggests that, theoretically, oral administration of bicarbonates andantacids should be avoided. Oral administration of ascorbic acid to further reduce chromium(VI) tochromium(III) might further decrease bioavailability (HSDB 1998), although this has not been proven(MEDITEXT ® 1997). Other recommendations for reducing gastrointestinal absorption of chromiuminclude diluting with water or milk followed by gastric lavage. Inducing emesis with syrup of ipecac isnot recommended because of the possibility of irritation or burns to the esophagus (Nadig 1994;MEDITEXT ® 1997). Activated charcoal has not been evaluated in chromate poisoning, but activatedcharcoal adsorbs metals poorly, so it would probably be of little use (MEDITEXT ® 1997).In cases of dermal exposure, the skin should be thoroughly washed to prevent chromium absorption bythe skin (HSDB 1998). As chromium(VI), but not chromium(III), is readily absorbed by the skin,ascorbic acid in the washing solution could reduce chromium(VI) to chromium(III), thus decreasingabsorption. Application of the calcium disodium salt of ethylenediamine tetraacetic acid (EDTA), whichacts as a chelating agent, has also been recommended after washing with water and application ofascorbic acid (Nadig 1994), especially in cases where the skin has been cut or abraded (Burrows 1983).Ascorbic acid was found to protect chromium-sensitive workers who handled chromates in thelithographing and printing industries from dermatitis. The ascorbic acid (10% solution) was kept near thework areas, and the workers soaked their hands and forearms as soon as possible after handling thechromate mixtures. In addition, ascorbic acid prevented ulcerations of the skin in rats treated with