In this issue, Beaumont et al report cancer mortality rates associated with exposure to high concentrations of hexavalent chromium in well water in Liaoning Province, China. Contamination of drinking water at these levels has been reported only once before, among a small group in Mexico. The investigation in China is a convoluted tale. The first report indicated an increase in cancer mortality, while a subsequent publication with the same lead author claimed no increased risks. In 2006, the journal publishing the latter paper retracted it because of failure to disclose financial and intellectual input to the paper by outside parties (linked to chromium polluting industries). Beaumont and his colleagues now provide a further reanalysis of these data, showing increased mortality in particular from stomach cancer, but with serious limitations in the data and methods of analysis. These limitations are counterbalanced by the importance of a study of perhaps the highest exposure to hexavalent chromium in water that will ever be experienced by a population large enough to estimate risks of cancer.
From the School of Public Health, University of California, Berkeley, California.
Submitted 14 September 2007; accepted 25 September 2007.
Supported by NIEHS grant P42 ES04705, and from the Center for Occupational and Environmental Health, University of California, Berkeley.
Correspondence: Allan H. Smith, School of Public Health, University of California, Berkeley, CA 94720. E-mail: email@example.com.