The Water Quality Assn. (WQA), a founding member of the European Drinking Water (EDW...
New chromium-6 standards are still being developed
Several weeks ago, U.S. Environmental Protection Agency (EPA) Administrator Lisa P. Jackson committed to address hexavalent chromium (also known as chromium-6) in drinking water by issuing guidance to all water systems on how to assess the prevalence of the contaminant. This week, the agency issued guidance recommending how public water systems might enhance monitoring and sampling programs specifically for hexavalent chromium. The recommendations are in response to emerging scientific evidence that chromium-6 could pose health concerns if consumed over long periods of time.
“Protecting public health is EPA’s top priority. As we continue to learn more about the potential risks of exposure to chromium-6, we will work closely with states and local officials to ensure the safety of America’s drinking water supply,” said Jackson. “This action is another step forward in understanding the problem and working towards a solution that is based on the best available science and the law.”
The enhanced monitoring guidance provides recommendations on where the systems should collect samples and how often they should be collected, along with analytical methods for laboratory testing. Systems that perform the enhanced monitoring will be able to better inform their consumers about any presence of chromium-6 in their drinking water, evaluate the degree to which other forms of chromium are transformed into chromium-6 and assess the degree to which existing treatment affects the levels of chromium-6 in drinking water.
EPA currently has a drinking water standard for total chromium, which includes chromium-6, and requires water systems to test for it. Testing is not required to distinguish what percentage of the total chromium is chromium-6 versus other forms such as chromium-3, so EPA’s regulation assumes that the sample is 100% chromium-6. This means the current chromium-6 standard has been as protective and precautionary as the science of that time allowed.
EPA’s latest data show that no public water systems are in violation of the standard. However, the science behind chromium-6 is evolving. The agency regularly re-evaluates drinking water standards and, based on new science on chromium-6, has already begun a rigorous and comprehensive review of its health effects. In September 2010, the agency released a draft of the scientific review for public comment. When the human health assessment is finalized in 2011, EPA will carefully review the conclusions and consider all relevant information to determine if a new standard needs to be set. While EPA conducts this important evaluation, the agency believes more information is needed on the presence of chromium-6 in drinking water. For that reason, EPA is providing guidance to all public water systems and encouraging them to consider how they may enhance their monitoring for chromium-6.