NRC to Review Inorganic Arsenic

The National Research Council (NRC), part of the National Academies of Sciences, is beginning a review of inorganic arsenic to support EPA’s IRIS program.  EPA’s Integrated Risk Information System (IRIS) process evaluates the health effects data related to environmental contaminants.  This toxicological review considers hazard identification and dose response assessment but does not consider exposure assessment or risk characterization.  The results of the IRIS evaluations are the basis for EPA’s regulatory development process, which includes consideration of other factors and eventually leads to regulatory decisions, such as establishing MCLG’s and MCL’s.  This special committee of the NRC is now advising EPA on the conduct of the assessment for arsenic.  When EPA has completed their IRIS assessment, the committee will again weigh in on the final assessment results.  A previous NRC report on EPA’s assessment on formaldehyde criticized the process EPA was using to conduct IRIS assessments and Congress asked EPA to use the NRC to review the planned update of the assessment on arsenic.

The NRC committee will plan and conduct a workshop to evaluate critical scientific issues in assessing both cancer and noncancer effects from oral exposure to inorganic arsenic.  The NRC may consider whether inhalation risks should also be evaluated.  The NRC will offer input on the methods and criteria for selecting scientific studies to include in the evaluation.  EPA wants to adopt a systematic review process for research studies to be used in the evaluation and welcomes NRC assistance in this process.  The NRC will also offer advice on approaches to evaluating critical studies, weight-of-evidence analyses, and justification of modeling approaches in the IRIS assessment. The new assessment of arsenic will also likely include consideration of metabolites of arsenic, since they also have significant health impacts.

The workshop that NRC is charged with conducting will be held in April of this year.  Their interim report will be provided to EPA in the fall.  This will support the toxicological review of inorganic arsenic which EPA is scheduled to complete in draft form by spring 2014.  The final IRIS assessment report, after NRC and other peer review, is scheduled to be released in 2016.

For more information on IRIS, visit the EPA IRIS website.  To follow the NRC process, visit their website on the inorganic arsenic review