Cancer mortality in a Chinese population exposed to hexavalent chromium in water

This report is a clarification and further analysis of our previously published mortality study regarding groundwater contamination with hexavalent chromium (Cr+6) in the JinZhou area of China between 1965 and 1978. In our previous report, we stated that a significant excess of overall cancer mortality was observed (P = 0.04) in five Cr(+6)-contaminated villages combined. Further analysis revealed no clear statistical increase in cancer mortality in the three villages adjacent to the source of the contamination (P = 0.25), where 57% of the wells exceeded the European Community safe drinking water standard of 0.05 ppm Cr+6. These results do not indicate an association of cancer mortality with exposure to Cr(+6)-contaminated groundwater, but might reflect the influence of lifestyle or environmental factors not related to Cr+6. Further follow-up of this cohort is recommended.