ACWA to Host Webinar on Chromium 6
ACWA is sponsoring an hour-long webinar Nov. 15 on hexavalent chromium (chromium 6) and the latest research and regulatory developments.
The session will include a brief background on regulatory and legislative action related to chromium 6 in drinking water, the status of the state’s draft public health goal (PHG), EPA’s Integrated Risk Information System (IRIS) review, and a multifaceted research project currently under way to address data gaps in the science regarding ingestion risks.
ACWA members and others interested in participating must sign up by e-mail no later than 5 p.m. Nov. 2. Participants will receive detailed instructions to access the webinar. There is no cost to participate. To sign up, please e-mail Danielle Blacet.
What: Hexavalent Chromium Webinar: What you Need to Know including Mode of Action Research Efforts
When: Nov. 15, 2010, 10 a.m. - 11a.m. (PST)
Login: Please e-mail Danielle Blacet for additional instructions
More on the study
Mode of Action Cancer Research Project for Ingestion of Hexavalent Chromium In 2008, the National Toxicology Program (NTP) finalized a two-year drinking water study of hexavalent chromium [Cr(VI)] that reported intestinal tumors in mice and oral cavity tumors in rats. Using these data, federal and state agencies have drafted cancer risk assessments for ingestion of Cr(VI).
Although the NTP study demonstrated clear evidence that Cr(VI) induced cancer in rodents, the concentrations of Cr(VI) administered in the NTP study are far in excess of typical environmental exposures; and may have overwhelmed the normal protective mechanisms that are thought to limit the carcinogenic potential of Cr(VI) following ingestion.
Moreover, the findings of the NTP study raise numerous questions about how Cr(VI) caused tumors in animals (the mode of action or MOA) and the relevance of these findings to humans who are exposed at much lower levels.
To address data gaps in the MOA, a multifaceted research project was designed and is currently under way. The project includes a 90-day drinking water study in rats and mice with comprehensive examination of the biochemical and genomic changes that provide critical insights into the key events associated with Cr(VI)-induced tumor formation.
Additionally, the MOA Research Project includes in vitro high-content imaging study and biokinetic modeling to characterize the potential species differences in tumor formation and to determine whether the carcinogenic doses in the NTP (2008) study are relevant to humans at environmental exposure levels.
Although the study will not be completed until the second quarter of 2011, this presentation will provide an overview of the study design and a summary of findings to date, which include most of the genomic and biochemistry data for the mouse study and some early data from the rat study.
A related paper was recently accepted for publication in Toxicological Sciences. See the Oct. 14 additions on the Toxicological Sciences website.
The full accepted paper is publicly available and provides a detailed discussion of how ToxStrategies used the EPA Mode of Action Framework to suggest key events in the MOA and design a study to address the data gaps.
For those interested in further reading, this paper provides many technical details we will not be able to cover in the presentation due to time restrictions.
The webinar will be presented by ACWA and ToxStrategies, Inc. and the research project has been funded by the Hexavalent Chromium Panel of the American Chemistry Council.
