More scrutiny urged on water contaminants

Southern Nevada scientists plan to expand studies on the water quality in the Las Vegas Wash and Lake Mead, including research on estrogen and prescription drugs found in treated sewage.

Bill Burke, a National Park Service biologist, urged the Lake Mead Water Quality Forum Thursday to investigate effects from hormones found in fish.

A 1996 study of bottom-feeding carp in the lake revealed male fish carrying egg-yolk protein normally found only in females. Those carp had the highest levels of the protein in a nationwide survey.

Recent work in Great Britain shows that fish carrying female protein also may develop eggs in their testes or other odd sexual traits, he said. No further studies in endocrine disruption found in Southern Nevada carp have been conducted.

A federal study of tissues sampled from sports fish such as bass in Lake Mead indicated no warnings are necessary.

Burke urged the forum, meeting at the Henderson Convention Center, to investigate removing estrogen and synthetic hormones from treated sewage. Two British studies indicated high levels of estrogen in male migratory birds, he said.

What effects hormones and drugs in drinking water may have on people are not now known.

The Las Vegas Valley drains its surface, sewage and flood waters into the Las Vegas Wash, leading six miles downstream to the drinking water intake pipe.

The man-made influences on water quality and wildlife from substances other than germs and chemicals are new concerns raised by scientists during the 1990s.

Biologist Larry Paulson, a forum member, said scientists have detected prescription drugs such as antibiotics and beta blockers in water supplies.

"Many contaminants we've never even thought of before," Paulson said.

"We have significant impacts on water quality," Paulson said. "Let's get busy and do something about it."

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