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EPA Holds Stakeholder Meeting on LT2 Review

One of the regulations EPA is reviewing in response to Executive Order 135653 is the Long Term 2 Enhanced Surface Water Treatment Rule (LT2).  One initial formal step in EPA’s review process was a stakeholder meeting on December 7, 2011 in Washington, DC.  The meeting supports the Executive Order review and EPA’s regular “Six Year Review” but also fulfills a commitment made during the M/DBP Federal Advisory Committee process to consider the impact of the round 1 cryptosporidium results on the second round of monitoring (scheduled to begin in 2015).  EPA shared the results of the first round of LT2 monitoring for cryptosporidium which showed a much lower level of detects than originally projected when the LT2 rule was promulgated.  This was evident in a lower mean of the number of cryptosporidium oocysts per liter and also a higher percentage of non-detects.  Some attendees questioned what the impact of these reduced cryptosporidium levels should have on the second round of monitoring.  Could it be eliminated or reduced if water quality was better than originally thought?   Although the good results do raise those questions, other commenters pointed out that cryptosporidium occurrence is still quite variable and not finding cryptosporidium one time does not mean that it won’t be found the next time.  Although there was not enough analysis to document a specific correlation, the use of the E. coli screen at small systems does appear to focus the cryptosporidium monitoring for small systems on the more at-risk water bodies.

Another issue discussed during the meeting was the analytical method (EPA 1623) and the possibility of using molecular methods to further define the exact species and even the genotype of the cryptosporidium.  EPA presented information on modifications to the method that would improve the performance in difficult matricies like those with sediment or debris in the water.  In order to mandate these method changes, EPA would have to adopt a new regulation; but because 1623 is a performance based method, individual laboratories could implement these improvements at any time as long as the method performance was maintained.  Some in the audience encouraged EPA to consider other method improvements that individual labs have offered.

Molecular diagnostic tools (“genotyping”) could help identify the specific species or genotype that is found in the source water.  So far, they have been used primarily to determine the source in particular contamination incidents because they can determine whether the source is deer or cattle — and even down to the specific farm that may be involved.  Because only a limited number of cryptosporidium species are known to be human health threats, this additional level of detail in the sample results is thought by some to suggest the need for a different response to positive detects than that required by the current rule (where all detects are treated equally).  Although much progress has been made on these methods, it does not appear that EPA believes they are ready yet for routine use and will still be confined to a small number of labs to meet special needs.

EPA has made no decisions about changing any aspect of the rule at this point but they should have a better idea what direction to take after the spring stakeholder meeting.  The spring stakeholder meeting will cover the requirement to cover finished water reservoirs and possibly additional LT2 issues.  A date has not been set although the meeting is likely to be held in DC.  Additional meetings are possible to address other issues.