The first public meeting held to review LT2 as part of EPA’s retrospective review process was held at EPA headquarters in Washington, DC on December 7. The full day meeting focused on preliminary results from the first round of Cryptosporidium monitoring under LT2 and potential improvements to the analytical method (Method 1623) used for Cryptosporidiumdetection and quantification. Presentations from the public meeting are available on AMWA’s regulatory committee webpage.
One of the major presentations at the meeting was EPA’s preliminary summary of results from round 1 LT2 monitoring. Initial analysis of results from round 1 monitoring indicate that water systems are detecting Cryptosporidium at levels 50% lower and at average concentrations over three times lower than projected during the LT2 regulatory development process. Reasons for this marked decrease from initial projections are only speculative at this point, but EPA committed to providing further breakdowns of the data and will be working to release the raw data to stakeholders so further independent evaluations can be conducted.
The other focus of the meeting was an evaluation of Cryptosporidium analytical methods. The first methods discussion surrounded the potential to use genotyping to differentiate Cryptosporidium subspecies that are known human pathogens from those that affect only specific animal hosts. Although the methods are available and improving quickly for this type of analysis, the consensus portrayed by EPA was that the methods were “not ready for prime time” but it was continuing work in this area. Some stakeholders thought that this approach was overly cautious and that there was at least an opportunity to use existing data on Cryptosporidium genotyping in its reevaluation of LT2 as a whole.
The second methods discussion focused on Method 1623 performance. Data presented on observed matrix spike recovery indicates that Cryptosporidium recovery rates are in line with projections (~40%) made during the initial LT2 evaluations, though there was significant variability between different laboratories and matrices. Data was also presented indicating that some labs may be able to significantly increase Cryptosporidium recovery by making fairly simple and cost-effective method improvements. By improving rinsing techniques, some laboratories observed an average improvement in recovery of 43%. Because of this demonstrated improvement in performance, EPA is contemplating a method revision to incorporate these changes, potentially prior to round 2 LT2 monitoring.
Overall, it is not yet clear how all of these findings may impact the round 2 monitoring process or the overall LT2 retrospective review, as EPA is only in the preliminary stages of evaluating the new data and did not have any recommendations for definitive action. Of particular concern to several meeting attendees is the potential for a change to Method 1623 to significantly change treatment bin classification in response to Cryptosporidium monitoring results. A closer look at the round 1 monitoring data coupled with newer human health data and associated risk assessment impacts may also indicate a need to reevaluate the setting of treatment bin boundaries regardless of impacts from proposed method changes. Although EPA stated that it would continue to look at potential binning impacts and input from stakeholders was welcome, no commitment to a specific process was forthcoming at this time.
The next LT2 public meeting is anticipated for the spring of 2012. Uncovered finished water reservoirs are slated to be the main topic for discussion, but EPA has floated the possibility that other topics may be added to the agenda. A Federal Register notice announcing the next meeting is expected in early 2012.