Two crypto cases seen in 1998

The Clark County Health District has recorded two cases of illness this year from a water-born organism that caused 43 deaths in the Las Vegas Valley four years ago.

Southern Nevada reported no cases in 1997 of the organism, cryptosporidium, that causes severe diarrhea. Both 1998 cases survived, health district reports for the last six months show.

The Centers for Disease Control and Prevention in Atlanta investigated Southern Nevada's outbreak of crypto, concluding it had spread through Southern Nevada's drinking water system, one of the most modern in the world. In 1994, at least 132 people suffered severe diarrhea and cramps in addition to those who died.

Cryptosporidiosis has been reportable to the Health District since 1992.

The Southern Nevada Water Authority is installing a system using ozone to treat and filters to capture critters such as crypto, because standard treatment with chlorine won't kill it.

SNWA microbiologist Peggy Roefer said no crypto cells capable of causing the disease have been found in local tap water.

Roefer said the SNWA laboratory constantly checks on bacteria, toxic chemicals, pesticides, metals and other stuff that could get into a glass of drinking water.

Last year, local water agencies issued a long list in customers' monthly bills of things that foul water. The news was good. The supply drawn from Lake Mead is safe, Roefer said. "It meets Safe Drinking Water Act standards," she said.

Testing the water supply is routine for Roefer because the valley's three sewage treatment plants dump an average of 150 million gallons of sanitized effluent each day six miles upstream from where the drinking water enters the valley's pipes. In addition, surface runoff, groundwater and floodwaters exit the valley through the Las Vegas Wash.

By spring or early summer 1999 Southern Nevadans will have their next report on the drinking water supply, said Vince Alberta, spokesman for the Southern Nevada Water Authority. "People can see for themselves," he said.

Next year the federal Environmental Protection Agency will require each of the nation's 56,000 water districts to alert their customers to the presence of pesticides, solvents, metals, bacteria and other regulated substances found in drinking water nationwide.

The information will resemble nutrition labels attached to most food products. At least once a year, customers will be able to read benign trace elements such as calcium, as well as heavy metals and pesticides.

Southern Nevada's water is unique in another way. Last year the rocket fuel oxidizer perchlorate was found in drinking supplies from Los Angeles to Las Vegas. Two industrial plants in Henderson made ammonium perchlorate for boosting solid rocket fuel performance for 40 years.

A national effort to investigate perchlorate's effects on people is under way. Perchlorate was used earlier this century to treat patients with over-active thyroid glands. But perchlorate can slow growth in children and in heavy doses can cause other health problems.

The highest level of perchlorate discovered in Las Vegas Valley was 16 parts per billion in a reservoir on Oakey Boulevard. Typical levels found in Southern Nevada waters range between 9 parts per billion and 16 parts per billion.

This summer's floods flushed out perchlorate, dropping levels in the lake to 6 parts per billion.

There is no standard for perchlorate in drinking water. However, California has set a safety margin of 18 parts per billion for drinking supplies.

California is the only state that already requires water suppliers to tell consumers what is in the water. The new federal guidelines will offer customers even more information.

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