Chromium and its compounds: Evaluation of risks to health from environmental exposure in Canada

Abstract

In this assessment of chromium as a Priority Substance under the Canadian Environmental Protection Act, available data on both hexavalent and trivalent chromium were evaluated to determine if levels of either form of this element present in the Canadian environment pose a risk to human health. Hexavalent chromium has been classified as “carcinogenic to humans”, based on the sufficient weight of evidence of carcinogenicity in occupationally exposed populations. Based on the comparison of estimated exposure in Canada to the potency of inhaled hexavalent chromium to induce lung tumours, the priority for analysis of options to reduce exposure in the general environment is considered to be moderate to high compared to that of other substances assessed under CEPA. In addition, hexavalent chromium may induce skin sensitivity in a small portion of the general population. On the basis of the inadequate database on carcinogenicity in animals and the limited epidemiological database, trivalent chromium has been classified as “unclassifiable with respect to carcinogenicity in humans”. Trivalent chromium is considered to be an essential element in human nutrition for which estimated intake does not exceed the recommended intake. Moreover, based on the limited available database, effects in animals or humans occur only at concentrations several orders of magnitude greater than those in the general environment.