As the Marketing Manager at Environmental Standards, I am constantly in awe of the knowledge possessed by my scientifically-technical colleagues. They are extremely talented chemists, geoscientists, biologists, and information technologies gurus who have the fortune to work on very interesting projects for a variety of clients; however, I would imagine that there are days when data validation or Phase I environmental site assessments may feel monotonous. But then comes the day they get to work on a project that has the potential to influence federal drinking water standards for hexavalent chromium [Cr(VI)], for example. As someone who wants to make a difference in my little corner of the world, I’d call that a good day at work.
While preparing blog posts or articles for The Standard, my colleagues and I are often focused on the role Environmental Standards played on a project. Essentially, we’re looking at one piece of a puzzle. So when I read a recently published paper co-authored by our alliance partner ToxStrategies, Inc., I wanted to know how Environmental Standards’ work fit into the puzzle as a whole.
In September 2010, US EPA released a draft assessment for Cr(VI) for peer review and public comment. Following a May 2011 meeting of an independent expert peer review panel to review the draft assessment, the panel urged US EPA to consider the results of research that would soon be completed. The panel believed the private research could provide relevant scientific information that might inform the Cr(VI) risk assessment.
Fast forward to today and the results of that research are coming to light in a new paper, Synchrotron-Based Imaging of Chromium and γ-H2AX Immunostaining in the Duodenum Following Repeated Exposure to Cr(VI) in Drinking Water. The peer-reviewed research paper is published in the January 2015 Issue of Toxicological Sciences. This paper is just one of 16 research papers written by scientists at ToxStrategies on the topic of Cr(VI) since the US EPA’s September 2010 assessment.
Lead author of the study, Chad M. Thompson of ToxStrategies said, “The results of this paper have the potential to impact how the US EPA will derive safe levels of Cr(VI) for drinking water.” The study, funded by the Hexavalent Chromium Panel of the American Chemistry Council (ACC), conducted targeted research to understand how Cr(VI) causes cancer in mice. The current US EPA regulations assume Cr(VI) causes cancer via direct genotoxicity.
The results of this most recent study support that cancer in the intestines of mice arises instead through chronic toxicity [long-term exposure to high doses of Cr(VI)].
Using particle acceleration technology in the National Synchrotron Light Source (Synchrotron) at the Brookhaven National Laboratory, and the incredible images produced there, researchers were able to see that little or no Cr(VI) reached the stem cell compartment of the intestines of mice exposed to 180 ppm Cr(VI).
Rock Vitale of Environmental Standards was aware of the technology available through the Synchrotron, which resulted in collaboration between ToxStrategies researchers and the US Army Corps of Engineers, who utilized the Synchrotron to complete the study. Once the data was available, Environmental Standards’ chemist Kyle Clay helped to interpret the data and provided validation of the accuracy of the results.
The US EPA is currently working on their assessment of Cr(VI) through the Integrated Risk Information System (IRIS) program. It is typical for the Agency to use peer-reviewed literature to develop standards. It is anticipated that this and other work completed by ToxStrategies will help the US EPA develop toxicity values and drinking water standards for Cr(VI). The new draft assessment is scheduled to be released in 2016.
The study sponsor (the Hexavalent Chromium Panel of the ACC) has generously made the complete paper available for free download (i.e., Open Access). Click here for the PDF.