TOXICOLOGICAL PROFILE FOR CHROMIUM - Davidborowski.com

CHROMIUM 542. HEALTH EFFECTS2.2.1.7 Genotoxic EffectsSeveral studies were located that investigate the genotoxic effects of chromium exposure on workers inchromium contaminated atmospheres. An epidemiology study of stainless steel welders, with meanexposure levels of 0.055 mg chromium(VI)/m 3 or 0.081 mg chromium (total)/m 3 , did not report increasesin the number of sister chromatid exchanges in the lymphocytes of exposed workers. The welders werealso exposed to nickel and molybdenum from the welding rods (Littorin et al. 1983). A similar study wasconducted to detect genotoxic effects of chromium(VI) on workers in electroplating factories. Of the 24workers examined, none showed significant differences in sister chromatid exchange frequency (Nagaya1986). Similarly, no correlation was found between excretion of chromium in the urine and the frequencyof sister chromatid exchanges in 12 male chromium platers whose mean urinary chromium level was17.9 µg/g creatinine (Nagaya et al. 1991). No increase in chromosomal aberrations was observed in 17tannery workers exposed primarily to chromium(III) as compared with 13 controls (Hamamy et al. 1987).However, parallel measurements in these tannery workers showed that the average chromium levels inplasma (0.115 µg/L) and in urine (0.14 µg/100 L) did not differ from the nonexposed workers. Inaddition, stainless steel welders occupationally exposed to chromium(VI) for a mean of 21 years did nothave any increase in chromosomal aberrations or sister chromatid exchanges compared to a control group.No actual exposure levels were provided (Husgafvel-Pursiainen et al. 1982). Yet, other studies involvingelectroplaters and welders report a higher incidence of chromosomal aberrations or sister chromatidexchanges in lymphocytes of workers than in controls. In one study, a causal relationship betweenchromium exposure and the observed effects could not be established because the exposure wasconfounded by co-exposure to nickel and manganese (Elias et al. 1989a). In another study, althoughchromium workers were found to have higher rates of sister chromatid exchanges than workers exposedto nickel-chromium or controls (after adjusting for potential confounding factors), the differences werenot significantly correlated to chromium concentrations in blood or urine (Lai et al. 1998). The frequencyof sister chromatid exchanges in the lymphocytes of 12 workers exposed to chromium(VI) as chromicacid fumes in a chrome plating industry was significantly increased (Stella et al. 1982). Significantlyincreased incidences of chromosomal aberrations in peripheral lymphocytes were found in workersexposed to chromium(VI) as chromium trioxide in two of four electroplating plants. Of the two plantswhere the increases were significant, one was a "bright" plating plant, where exposure involved nickel aswell as chromium, and one was a "hard" plating plant, where exposure involved only chromium.However, the increase in chromosomal aberrations correlated poorly with urinary chromium levels, andonly the increase in the "bright" platers showed a significant correlation with duration of exposure. Asignificantly increased incidence of sister chromatid exchanges was found in "hard" platers compared