US Industry research to tackle California Cr6 risk assessments

Factiva: A key industry group is launching research to determine how hexavalent chromium causes cancer -- the first step in their effort to soften California's and other anticipated risk assessments and related regulatory standards that are expected to rely on a strict default assumption unless convincing data explains how the widely used metal causes cancer."

The Aerospace Industries Association (AIA) is funding an expansive two-year research project designed to evaluate potential biological modes of action (MOA) for how exposure to chromium 6 in drinking water causes cancer and to consider how chromium 6 converts into the nutrient trivalent chromium (chromium 3) in the body.

The research project -- launched before California's just-announced health goal -- was triggered by a 2007 study by the National Toxicology Program (NTP), which reported stomach and mouth tumors in lab animals exposed to chromium 6 in drinking water. "State and federal regulatory agencies are likely to re-evaluate their drinking water regulations for hexavalent chromium and will consider using the NTP cancer bioassay to develop an oral cancer slope factor for hexavalent chromium," notes the Web site of Toxicology Excellence for Risk Assessment (TERA), which has put together an expert panel to advise the research project.

The NTP study is the basis for the strict public health goal (PHG) California's Office of Environmental Health Hazard Assessment (OEHHA) proposed Aug. 20. The state is the first to propose a stand-alone measure to address the metal.

Currently, state and federal drinking water regulations address total chromium, or a combination of chromium 6 and chromium 3, the nutrient. EPA has an enforceable drinking water standard -- or maximum contaminant level (MCL) -- for chromium of 100 parts per billion (ppb), while California's MCL is a more strict 50 ppb.