Specific Substances: Sodium dichromate dihydrate (VI)
Nomination Date: 03/12/2001
Nominator: US Congressional Delegation from California
Rationale: Hexavalent chromium has been detected in the public drinking water supply of Los Angeles County and in drinking water obtained from wells in Southern California. The NTP is requested to conduct carcinogenicity studies to determine the potential long-term health risks associated with the presence of hexavalent chromium in drinking water. The State of California has established a public health standard of 50 parts per billion (the national standard is 100 parts per billion) and is considering lowering the permitted levels to no more than 2.5 parts per billion. The NTP carcinogenicity tests will contribute to the development of a scientifically sound standard for hexavalent chromium in drinking water and strengthen the confidence of Americans in the safety of the their drinking water.
NTP Principles: not specified