Perchlorate in the Pacific Southwest
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In Arizona, many water bodies near industrial and military sites are contaminated with perchlorate. Cleanup efforts at these sites are underway, with oversight by the EPA and ADEQ.
The concentrations of perchlorate in waters that are not near industrial sites are generally below the advisory level of 14 parts per billion established by the state. This reflects the maximum concentration of perchlorate in drinking water that can be consumed without causing adverse health effects (link to Fact Sheet).
Waters that are not near industrial sites have been deemed safe to drink by a 2004 state taskforce. The taskforce included the directors of four Arizona departments - Department of Environmental Quality, Health Services, Water Resources, and Agriculture. The group assessed the extent and impact of perchlorate contamination in state water sources.
State Advisory Level
As of April 2005, the Health Based Guidance Level is 14 ppb.
Most perchlorate contamination in Arizona is in the Colorado River watershed. Perchlorate contamination has been found to be moving through the Las Vegas Wash into Lake Mead, and then into the Colorado. The source of the perchlorate contamination has been identified as the Kerr-McGee manufacturing facility located outside of Las Vegas.
This thumbnail clicks to a map showing the locations of all perchlorate detections in Region 9 reported to EPA as of September, 2004.
In December 2004, a state of Arizona inter-agency task force released a report that concluded that perchlorate concentration in drinking water poses no threat to the Arizona public. The task force found that perchlorate levels in Colorado River water used for drinking are well below the state's Health Based Guidance Level (HBGL) of 14 parts per billion (ppb).