Based on my previous knowledge, perchlorate is ubiquitous in groundwater, although the sources are not always clear.  It’s used in dry cleaning, and rocket fuel (slightly different forms I think!) but there seem to be other sources.  It may be a breakdown product of some other chemical(s).  If I remember correctly, it has also been found on Mars!  

 

Mike Lazere

 

 

I admit to my ignorance; why is this stuff in the water and why does the gov’t want to keep it there? B

 

 

From today's American Progress Action report:
 
ENVIRONMENT -- THE WHITE HOUSE PRESSURES THE EPA TO NOT LIMIT PERCHLORATE IN TAP WATER: "Under pressure from the White House and the Pentagon," the Environmental Protection Agency (EPA) "is poised to rule as early as today that it will not set a drinking-water safety standard for perchlorate, a component of rocket fuel that has been linked to thyroid problems in pregnant women, newborns and young children across the nation," the Washington Post reports. A near-final version of  the EPA's "preliminary regulatory determination" that the Post obtained "assumes the maximum allowable perchlorate contamination level is 15 times what the EPA had suggested in 2002." The proposal is "the final step in a six-year-old battle between career EPA scientists who advocate regulating the chemical and White House and Pentagon officials who oppose it." Officials in the White House Office of Management and Budget (OMB) "heavily edited" the document by eliminating key passages and asking the EPA to "use a new computer modeling approach to calculate the chemical's risks." In 2004, the EPA's process for scientific risk assessments of chemicals was altered to give OMB oversight of the program, which increased the ability of other departments to interfere in the program secretly. Last spring, the Government Accountability Office reported "that the Pentagon had pressured the EPA for several years not to regulate perchlorate."