RE: [CPEO-MEF] Defense memo on Perchlorate

[walshw@pepperlaw.com]

From a toxicological point of view, it cannot be that 1 ppb is safe in
one state and 18 ppb in another.  There are obviously policy judgments 
being made.  Apparently, the various states are looking at the same data 
and using different safety factors/uncertainty factors.

It would be preferable for DoD to have one number, but most federal
environmental laws allow states to issue duly promulgated standards that 
are more stringent.  Generally, Federal restoration cleanups must meet 
these state limits.

One potential option is for US EPA, the States, DoD, and the citizen
stakeholders hold a joint peer review workshop on the appropriate
interim advisory level.  The interim advisory level could be national if 
all of the states agreed or it could apply in states that have not 
issued their own advisory if each state prefers to keep its current 
advisory level.

Second, the DoD could seek the advice of a National Academy of Science
Committee on this issue.  Typically, that takes two years.

Third, the DoD could convene the cleanup experts from these same
stakeholder groups and assess whether it makes any practical difference. 
The guidance could be written to minimize the impact of the cleanup 
goal and leave the ultimate decision for some later data.

Some times there are a number of potential remedial actions that are
applicable.  The level of cleanup that is achievable may in some cases, 
with little additional costs, be capable of meeting 1 ppb as well as 18 
ppb.

The question of whether the final cleanup level practically affects the 
remedy, however, may also vary on a site-by-site basis. If the
concentration at the edge of a typical plume decreases from very high 
concentrations (>> 18 ppb) to nondetect in a short distance, it may not 
make much difference except when it comes to the decision to turn off 
the ground water cleanup system.  Since that decision is typically many 
decades down the road (I do not know what it is for perchlorate), then 
language can be drafted that states the system can be turned off when X 
ppb is reached or the federal or state drinking water standard or ground 
water cleanup standard or criteria when or if one is duly promulgated.

Also, if the plume is going essentially in one direction, the difference 
between using a 1 ppb and 18 ppb may only affect the location of ground 
water collection wells (that is, it would move the location further 
downgradient).

However, if there is a much larger plume if 1 ppb is the cleanup goal
versus 18 ppb, then the difference will make a big cost difference.  In 
this situation, the interim cleanup goal or the state advisory would 
dictate the areal extent of the plume to be cleaned up.  

However, one could use institutional controls on a temporary basis for
the portion of the plume for which there is uncertainty and active 
cleanup for the heart of the plume. Once a final standard is duly 
promulgated, then the remainder of the plume could be remedied based on 
that final cleanup standard.

The final option for DoD is simply to use the most stringent cleanup
goal on the theory that one can always adjust the remedy to do less 
later and avoid the more expensive option of requiring more at a later 
date.

These are my quick and very dirty thoughts on the options that could be 
explored.


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