Editorial: Water ills need close attention

Monday, Jan. 28, 2002 | 8:39 a.m.

Perchlorate, a chemical used in rocket fuel, has found its way into drinking water in 40 states, including Nevada, and no one really knows at what saturation level it becomes dangerous to human health. All the Environmental Protection Agency can say is that perchlorate contamination is an emerging field and there may not be a definitive safety standard for another 10 years. Perchlorate was manufactured in Henderson for decades, and discharges from manufacturing plants were not required to meet strict environmental standards until the mid-1970s. Trace amounts of perchlorate have been detectable since 1997 in Lake Mead, the source of Southern Nevada's drinking water.

On Jan. 18 the EPA released a draft report stating that perchlorate may be a health hazard at levels above one part per billion. California, which had informally considered anything under 18 parts per billion as reasonably safe, responded by announcing a new standard of four parts per billion, which is currently the lowest amount that tests can detect. Water from Lake Mead is testing at about 14 parts per billion.

Southern Nevada water officials and the Nevada Division of Environmental Protection did not hesitate when perchlorate was detected five years ago. Monitoring was stepped up and cooperation was enlisted from the Department of Defense and the industries that had manufactured perchlorate here. Kerr-McGee Chemical Corp. in 1999 isolated and began treating one major source of seepage with a temporary system that has proven to work. Within the next few months the company will begin operating a permanent perchlorate removal system that is now under construction. The company says it will handle 825 gallons a minute and will be effective in removing all perchlorate from the water it treats. The water will be drawn from an area in the Las Vegas Wash that has been discovered to have a heavy concentration of the chemical.

Pat Mulroy, general manager of the Las Vegas Valley Water District, is realistic in assessing the perchlorate contamination. She is hopeful that this expanded effort will show a huge reduction in the parts-per-billion count. She notes that Southern Nevada has not waited around for the EPA to publish a final, definitive report. "Our objective is to get rid of it," Mulroy said. "But it took 50 years to get there, so it's not going to disappear overnight." Treatment plant technology is not yet sufficient to prevent perchlorate from coming through the taps at home. Because perchlorate does not occur naturally in nature, there are no natural protections, such as wetlands. And although scientists suspect that perchlorate could be damaging to thyroid glands, especially in newborns, no long-term health effects have been established. So how should Southern Nevada ns respond to the EPA's latest risk assessment?

Mulroy, who has dealt with perchlorate as part of her job since it was detected here in August 1997, says people need to evaluate their own level of health. People who are concerned, she said, should have reverse osmosis treatment systems installed in their homes and they should adhere strictly to the system's maintenance schedule. Bottled water, she said, is an alternative for people who cannot have filtering systems installed in their homes.

The contamination began during a time when people did not recognize it as a problem. As Mulroy says, in fighting to eradicate this chemical, we are only as good as the current science. As long as public agencies are responding with dispatch and the latest knowledge, it should not become an issue mired in finger pointing or undue alarm. Perchlorate contamination is a national problem that will be solved only if the federal government, local governments, and industry resolve to keep it a top public health priority.