TOXICOLOGICAL PROFILE FOR CHROMIUM - Davidborowski.com

CHROMIUM 712. HEALTH EFFECTStwo ferrochromium alloy industries are located. No indication was found that residence near theseindustries is associated with an increased risk of lung cancer (Axelsson and Rylander 1980).A retrospective mortality study conducted on a population who resided in a polluted area near an alloyplant that smelted chromium in the People's Republic of China found increased incidences of lung andstomach cancer. The alloy plant began smelting chromium in 1961 and began regular production in 1965,at which time sewage containing chromium(VI) dramatically increased. The population was followedfrom 1970 to 1978. The size of the population was not reported. The adjusted mortality rates of theexposed population ranged from 71.89 to 92.66 per 100,000, compared with 65.4 per 100,000 in thegeneral population of the district. The adjusted mortality rates for lung cancer ranged from 13.17 to 21.39per 100,000 compared with 11.21 per 100,000 in the general population. The adjusted mortality rates forstomach cancer ranged from 27.67 to 55.17 per 100,000 and were reported to be higher than the averagerate for the whole district (control rates not reported). The higher cancer rates were found for those wholived closer to the dump site (Zhang and Li 1987). Attempts to abate the pollution from chromium(VI)introduced in 1967 also resulted in additional pollution from sulfate and chloride compounds. It was notpossible to estimate exposure levels based on the description of the pollution process. The exposedpopulation was probably exposed by all environmentally relevant routes (i.e., air, drinking water, food,soil).A follow-up study reevaluated this cohort; the adjusted total cancer death rates for the six areas analyzedwere 68.8, 68.4, 64.7, 54.3, 57.5, and 45.9 (Zhang and Li 1997) . These rates were comparable to theoverall provincial rate of 66.1 in which the 6 exposed regions were located. When total cancer mortalityrates from five villages of the areas using the contaminated water were combined, a significant increase incancer incidence was observed over provincial incidences. However, total cancer incidences, stomachcancer incidence, or lung cancer incidence did not correlate with the degree of exposure to chromium(VI),with the villages exposed to the lowest drinking water levels having the higher incidences. The authorscommented that these more recent analyses of the data probably reflect lifestyle or environmental factorsrather than exposure to chromium(VI) being responsible for cancer in these regions.The studies in workers exposed to chromium compounds clearly indicate that occupational exposure tochromium(VI) is associated with an increased risk of respiratory cancer. Using data from the Mancuso(1975) study and a dose-response model that is linear at low doses, EPA (1984a) derived a unit riskestimate of 1.2x10 -2 for exposure to air containing 1 µg chromium(VI)/m 3 (or potency of