During a March 29 teleconference, EPA’s Science Advisory Board (SAB) gave preliminary approval of the path forward for setting a Maximum Contaminant Level Goal (MCLG) for perchlorate as recommended by the SAB Perchlorate Advisory Panel. Based on a draft report from the Advisory Panel, the SAB will recommend using an enhanced physiologically based pharmacokinetic (PBPK) model to derive an MCLG that would ultimately underpin a perchlorate regulatory decision.
In addressing the full SAB, Dr. Stephen Roberts, chair of the Perchlorate Advisory Panel, stressed that their report lays out recommendations at “the 5,000 foot level” for EPA to consider as it moves forward, but leaves it up to EPA to decide when the updated PBPK model is scientifically sound enough to support a policy decision. In the accompanying discussions with SAB members, estimates ranging from 1 to 10 years were mentioned as possible timeframes to revise the PBPK model underlying any policy decision, with the ultimate timeframe dependent on the amount of change made to the modeling approach.
The Advisory Panel will now make final edits (mostly for clarity) to its draft report to incorporate recommendations from SAB reviewers before it is approved by the full SAB and sent to the EPA Administrator. The current target for the final report submittal is sometime in May. Following receipt of the report, EPA will work toward issuing a proposed regulation by the end of 2013, though it appears that meeting that target will be difficult based on the timing and recommendations of the SAB report. The latest draft of the Advisory Panel’s report and other information on the SAB review process are available at the SAB Perchlorate Advisory Panel webpage.