Perchlorate cleanup hits mystery snag

Drillers at Kerr-McGee Chemical Corp. have discovered a mysterious substance in ground water, a finding that threatens to delay cleanup of the rocket-fuel booster perchlorate contaminating Southern Nevada's supply of drinking water.

Kerr-McGee plant manager Pat Corbett said Thursday the company plans to expand its testing after drillers sniffed an odor and an "effervescence," like soda bubbles tickling their noses, as they bored new test holes.

"It could be a pesticide in the ground water," Corbett said of the unexpected finding during sampling for 60 substances ranging from solvents to pesticides.

A pesticide could stop the use of the friendly bacteria employed to gobble up the perchlorate. "We use bacteria to clean our site," Corbett said. "It could kill our bugs."

Most of the tests taken from 29 new wells showed nothing. The sensation felt by the drillers in a couple samples also could come from the drilling process, he said.

Perchlorate concerns scientists because it can slow children's growth. There are national studies ongoing this summer to study its effects in rats.

There are no federal drinking water limits on perchlorate. California has set a guideline of 18 parts per billion. The highest level found in Southern Nevada waters was 16 parts per billion in a December test.

Kerr-McGee is in its second phase of testing for perchlorate, manufactured at the plant near Henderson for raising oxygen levels in rocket and space shuttle solid fuels. The site is about 15 miles southeast of Las Vegas.

A second perchlorate manufacturing plant, the former Pacific Engineering & Production Co., exploded and was destroyed by fire in May 1988. Its parent company, American Pacific Corp., moved operations in 1989 to Cedar City, Utah.

Kerr-McGee has drilled extensive new water wells and used existing boreholes to sample the ground water and soils from the plant, which is about 10 miles downhill from the Las Vegas Wash.

Corbett said Kerr-McGee will complete an 11-acre treatment pond by September to intercept contaminated ground water at the plant. The microscopic bacteria used to treat dangerous chemicals in water treatment will do their work there.

The company also is experimenting with a technological solution, an electrolytic cell used in Europe. The cell, however, can treat only six gallons of contaminated water an hour, he said.

Both companies are cooperating with the Nevada Division of Environmental Protection to prevent perchlorate from entering the wash feeding Lake Mead, Southern Nevada's major source of drinking water. American Pacific has denied it is the principal source of the contaminant.

Douglas Zimmerman, chief of corrective action for the NDEP in Carson City, said he had not had time to review the drilling report. The state expects to meet with Kerr-McGee officials next week.

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