December 5, 2008
Perchlorate is a chlorine-based contaminant that is both naturally occurring and manmade. It is a component of rocket fuel, and often ends up in groundwater through improper disposal practices by rocket test sites, military bases and nuclear weapons manufacturing facilities. Perchlorate exposure has adverse effects to human health. It interferes with intake of iodide by the thyroid gland, which leads to problems with metabolism and hormones in adults, and problems with proper development in children. Perchlorate especially affects people with thyroid disorders, pregnant women, developing fetuses and infants.
EPA determined that between 16,000 and 28,000 pregnant women nationwide are potentially at risk to perchlorate exposure in the areas where it has been detected, but EPA failed to account for such future health threats in its recent decision.
Curry asked in a letter to the EPA Administrator that the federal agency regulate perchlorate in order to protect drinking water supplies and human health. New Mexico pumps around 90% of its drinking water from groundwater.
At present, EPA does not regulate perchlorate in drinking water. It has set a Drinking Water Equivalent Level of 24.5 micrograms per liter. "EPA's new [official reference dose] RfD translates to a Drinking Water Equivalent Level (DWEL) of 24.5 ppb. A Drinking Water Equivalent Level, which assumes that all of a contaminant comes from drinking water, is the concentration of a contaminant in drinking water that will have no adverse effect with a margin of safety. Because there is a margin of safety built into the RfD and the DWEL, exposures above the DWEL are not necessarily considered unsafe." For more information, please visit "EPA Sets Reference Dose for Perchlorate
Release date: 02/18/2005." http://yosemite.epa.gov/opa/admpress.nsf/b1ab9f485b098972852562e7004dc686/c1a57d2077c4bfda85256fac005b8b32!OpenDocument Nevertheless, Massachusetts and California both have safety regulations in place setting a maximum limit of 2 micrograms per liter and 6 micrograms per liter, respectively.
There is limited data about perchlorate contamination. However, what data there is shows contamination in drinking water systems around New Mexico in such areas as Cannon Air Force Base in Clovis; Melrose Bombing Range near Clovis; Holloman Air Force Base near Alamogordo; White Sands Missile Range near Socorro; Kirtland Air Force Base and Sandia National Laboratories in Albuquerque and Los Alamos National Laboratory (LANL) in Northern New Mexico. The contamination levels vary, but detected levels range from 12.6 micrograms per liter found in a drinking water well at Kirtland, to an astounding 680 micrograms per liter detected in a monitoring well at Sandia.
Federal law requires EPA to regulate contaminants when they occur in drinking water at levels possibly threatening human health. However, EPA's recent decision is contrary to this requirement. The contamination at LANL alone potentially threatens the drinking water supply for the entire County of Los Alamos, which serves around 20,000 people. In his letter, Curry asserted that, "we must protect our state's limited drinking water supply from this harmful contaminant."
Joni Arends, of CCNS, said, "We are pleased with the Environment Department's action. However, given the number of findings and the high levels of contamination, CCNS urges the Department to make setting a state drinking water standard for perchlorate a priority."
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