While these data are limited, they are consistent with increased stomach cancer risk in a population exposed to Crz=6 in drinking water.

Recent analyses have revealed that 38% of municipal sources of drinking water in California have detectable levels of hexavalent chromium. This observation provided new impetus to characterize the carcinogenic risk associated with oral exposure to hexavalent chromium in drinking water. Notwithstanding the well-characterized increases in cancer associated with inhalation exposure to this chemical, the marked reduction of hexavalent chromium to trivalent chromium in the stomach suggests that exposure to hexavalent chromium in drinking water may not pose a carcinogenic risk. A reevaluation of studies that investigated the toxicokinetics, the genotoxicity, and the mechanism of carcinogenicity of hexavalent chromium, as well as the available human and animal cancer studies, was undertaken to determine if there is evidence that exposure to this chemical in drinking water may pose a carcinogenic risk. Mechanistic studies suggest the potential for a carcinogenic response if hexavalent chromium enters cells. Both toxicokinetic and genotoxicity studies indicate that a portion of an orally administered dose of hexavalent chromium is absorbed and gets into cells of several tissues, causing DNA damage. The only lifetime oral study of hexavalent chromium in animals conducted thus far yielded a statistically significant increase in stomach tumors compared to controls. Also, in a limited-term cancer study, co-exposure to hexavalent chromium in drinking water and ultraviolet light produced skin tumors in mice. The only available cancer study of humans exposed to hexavalent chromium in drinking water revealed a statistically significant increase in stomach tumors. Moreover, a meta-analysis of occupational studies also revealed a statistically significant increase in stomach cancers. The increases in stomach tumors in both human and animal studies, along with the toxicokinetic, genotoxic, and mechanistic data, suggest that oral exposure to this agent appears to pose a carcinogenic risk.

No abstract

A yellow-orange air-stable crystal (a near-cube, 0.50 × 0.50 × 0.40 mm) of the title compound was mounted and sealed in a glass capillary and placed on

Contaminated soil at depth can pose a threat to public health upon excavation. Following the excavation of contaminated soils, toxicants which once resided at depth become available for exposure due to direct contact. A scenario is developed that describes the excavation and redistribution of soil to the surface. Based on typical excavations occurring in a residential setting in California, soil to a depth of 10 feet is considered available for future exposure due to direct contact. The capabilities of various earthmoving equipment were employed to establish that the average toxicant level in 12 cubic yards of soil is the appropriate measure for evaluating contaminated soil at depth. This allows the evaluation of future risk to public health due to direct contact exposures following the excavation of contaminated soils at depth.