Perchlorate can persist for decades

Friday, May 1, 1998 | 10:03 a.m.

Solid perchlorate salts of ammonium, potassium and sodium can contaminate ground or surface waters.

Perchlorate salts are easily dissolved in water. They can persist for decades under typical groundwater and surface water conditions.

Perchlorate is used as a rocket fuel oxidizer in munitions and in fireworks. Because of its shelf life, it is periodically washed out of the rocket and missile inventory and replaced with a fresh supply.

At sites in California at Aerojet and Mather Air Force Base, Edwards Air Force Base and in Nevada at the former Pacific Engineering & Production Co. and Kerr-McGee Corp. near Henderson perchlorate has contaminated ground and surface waters.

California scientists discovered a way to test for perchlorate between 400 parts per billion and 4 parts per billion in 1997. That discovery led to finding perchlorate in California and Nevada water supplies.

The chemical was found at levels between 5 parts per billion and 9 parts per billion in the Colorado River, a source of drinking water to 1 million Nevadans, more than 10 million Californians and 1 million Arizona residents.

There is no drinking water standard for perchlorate. California set a guideline of no more than 18 parts per billion in drinking supplies.

Perchlorate also has been found in California, Nevada and Utah wells.

The federal Environmental Protection Agency is required to develop a list of contaminants that are potential candidates for future drinking water research. Perchlorate has been included on the candidate list.