LV growth will only increase lake pollution

Friday, April 11, 1997 | 11:59 a.m.

Dangerous bacteria counts and other disease-causing organisms found in Lake Mead have water experts worried about the continued growth boom in Southern Nevada.

Biologist Larry Paulson, who tested water in Las Vegas Wash and the lake for 15 years, said warning signs should have been posted following a cryptosporidium outbreak in 1994 that killed 43 Las Vegas residents and infected 132 others.

"Why don't they do it? Put up signs and say, 'This is polluted water: Swim at your own risk,'" said Paulson, a consultant for the Nevada Seniors Coalition.

The coalition is fighting expansion of Southern Nevada's drinking water system because doubling the population will double the treated effluent into Lake Mead, the major drinking water source for Nevada and California.

Las Vegas Wash and Lake Mead's Las Vegas Bay collect all treated sewage and surface runoff six miles upstream from the pipeline that supplies the valley's 1.1 million residents and 32 million visitors with drinking water. A second line is due to open this summer in the same location.

Allen Biaggi, deputy administrator of the Nevada Division of Environmental Protection, said impacts from growing amounts of treated wastewater and runoffs from Las Vegas Valley pose serious consequences in the future if problems are not addressed.

"It's going to be a challenge," he said.

Biaggi heads the Lake Mead Water Quality Forum, a group of federal, state and local water and wastewater officials, meeting regularly on water quality since January.

The Centers for Disease Control and Prevention in Atlanta investigated the Las Vegas cryptosporidium outbreak and indicated drinking water was the source. The CDC investigation discovered no indications of cryptosporidium at the time, but in 1995 the city of Las Vegas found evidence of crypto and Giardia, another cause of waterborne illness, in its samples taken during tests of effluent.

"We really wanted to know how much might be there," said Debra Bolding, superintendent for the city's environmental division laboratory at its water pollution control plant.

"I wish we had done more work. Yes, the plant is a source for crypto, but it's in the range of other treatment plants."

Any feces from humans or animals can spread cryptosporidium, she said.

Testing for the cryptosporidium is difficult and treatment requires expensive filtering or applying ozone to the water to kill the cell that can last six months under extreme condition that would destroy other forms of organisms, she said.

No federal or state laws exist that limit cryptosporidium in water, which can cause bloody diarrhea and death in people with weak immune systems, organ transplants, diabetics, the elderly and the very young. The federal government will set a standard by the year 2000.

Paulson has reviewed some data from seven monitoring stations stretching from the wash into the lake and reported high fecal coliform counts.

"They're in violation (for coliform) at the LVW-1 monitoring station, just downstream from the city's and county's sewage treatment plants," Paulson said.

Each of the three treatment plants -- for Las Vegas, Clark County and Henderson -- all report that their discharges are much lower than the strict clean water standards set by federal and state regulators.

It was the federal Bureau of Reclamation and the U.S. Geological Survey reports that alerted state and local water officials to bacteria, pesticides and toxic chemicals in the wash and bay last year.

A USGS study released in November measured chemicals, banned in the U.S. for more than 20 years, in carp from Las Vegas Bay. The fish had the highest levels of such chemicals of 21 sites nationwide.

Paulson said he doesn't know why there's such a discrepancy on what's reported and what federal scientists are finding in the wash. The reports contained missing data, he said.

Missing data occurred because each plant used a different computer program, Bolding explained. UNLV is creating a central system that could be ready as early as this summer to allow uniform readings of hundreds of thousands of numbers, she said.

The Bureau of Reclamation has tracked pollution through the wash and into the lake for more than six years, with bacteria counts too high to measure.

But high levels of fecal coliform, a bacteria shed by people and animals, have affected uses of the wash and bay for 20 years, Biaggi said. The state Environmental Commission restricted human contact in both areas more than 15 years ago. However, there's no public warning of contaminated waters.

"There are no warning signs posted," Biaggi said. That will be a major topic for the forum's April 24 meeting, he said.

In the future, the state may order further tests on the coliform to find out if it comes from animals or humans he said.

Contamination sources suspected of boosting the bacteria include animal wastes, surface runoff, wildlife and homeless, some water experts said.

"To blame contamination at the levels we have on birds and animals, or the homeless, is absolutely ridiculous," Paulson said.

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