4 August 2003
Scientists tracking perchlorate pollution

By Natalie Patton

Lambis Papelis, a Desert Research Institute scientist, helped look into the migration of perchlorate, a rocket fuel ingredient, in the Las Vegas Wash area.
Photo by Amy Beth Bennett .
Rebekah Harris-Burr, a UNLV chemistry graduate student, works in a Desert Research Institute lab. Scientists at the institute joined UNLV researchers on a U.S. Environmental Protection Agency-sponsored perchlorate contamination study completed in March.
Photo by Amy Beth Bennett .

When perchlorate suddenly became a household word in Southern Nevada, Desert Research Institute scientist Lambis Papelis was among the Nevada university system researchers called upon to expose the rocket fuel ingredient's travel habits and relationship patterns.

Papelis, a water chemist for the past nine years at the statewide research center, joined UNLV researchers as a co-principal investigator on a U.S. Environmental Protection Agency-sponsored perchlorate contamination study completed in March.

Perchlorate, produced for decades in Henderson-area chemical plants, interferes with thyroid gland functions and human development. Infants, young children and pregnant women are most susceptible.

"What we were looking at was the potential for migration of perchlorate in the area around the Las Vegas Wash," Papelis said. "Where did it come from? Where is it going? How long would it take to get there? Could this perchlorate be reduced in the soil by micro-organisms? And would it be retarded by soil at all?"

Papelis, 46, said the answer to the last question is no. Perchlorate travels with water and doesn't jump out of the flow to stick to soil or other surfaces.

"Essentially, if you know how the water's moving, you also know how the contaminant is moving," he said.

The answer to whether micro-organisms could help in the fight to get perchlorate out of Southern Nevada's drinking water is probably not. Papelis said desert soils don't have enough food to fuel the work of microbes that otherwise would be eager to consume perchlorate.

The study included lab research, computer modeling and sampling along the Las Vegas Wash and in wells tapping into groundwater.

"The main conclusion is there's a lot of perchlorate, and Kerr-McGee is doing a pretty good job of intercepting some of the perchlorate, but not everything," Papelis said. "You can build a barrier to stop the plume, but you have to deal with the backup. It will be years before we can flush out all of the perchlorate from the area between the manufacturing plant and the Las Vegas Wash. It's not something that's going to go away tomorrow. There's still a lot of perchlorate on its way down there."

Scientists hired by Kerr-Magee and the Southern Nevada Water Authority have determined the source of perchlorate and the contaminant's path. University system researchers have added to the knowledge base in the short time Lake Mead perchlorate contamination has been a concern.

The Environmental Protection Agency is working on establishing a national standard for safe perchlorate levels in drinking water. That could be four to six years out, although pressure is mounting to speed up the process.

"We don't even know if what we're drinking now will be considered safe in two or three years," Papelis said. "The absence of a standard makes people a little bit more nervous. Is it safe to drink, or not?"

In the late 1990s, California surprised Nevada by detecting perchlorate in the Colorado River.

The source of the river's perchlorate was found to be Lake Mead, which was being polluted by flows from the Henderson-area industrial complex that for decades produced the toxic rocket fuel ingredient. Perchlorate manufactured at Kerr-McGee Chemical Corp. and the former Pacific Engineering & Production Company of Nevada continues to reach groundwater.

Because of the presence of military bases around the country and their use of perchlorate, at least 22 states have varying levels of perchlorate pollution.

"It will be a problem for many, many water operators, not just Southern Nevada," Papelis said about the possibility the upcoming EPA standard will force greater drinking water cleanup measures.

Lake Mead's perchlorate problem has received so much attention because it is a source of drinking water for millions in the Western United States and an irrigation source for farmers in California's Imperial Valley, who grow the bulk of the nation's winter lettuce crop.

Papelis, a scuba diver and instructor at Lake Mead, also has his attention on selenium levels in the Las Vegas Wash's nature preserve.

Selenium is being monitored at pools in the Las Vegas Wash's new nature preserve to see whether they are reaching levels that would threaten the health of birds and other wildlife attracted to the area.

In small concentrations, selenium is essential for normal functioning of the immune system and thyroid gland, but it can quickly reach toxic levels.

Water that used to flow into the wash is now sitting in pools and picking up more selenium from the desert soil, which has high concentrations of the element in the West.

"We're going to see if there's something we need to worry about," Papelis said. "We're trying to look ahead, as opposed to trying to react in an emergency."

In addition to his work at a research institute largely funded by grants and contracts awarded to its scientists, Papelis teaches a basic chemistry class at Nevada State College at Henderson, heads the Water Resources Management master's program at the University of Nevada, Las Vegas and is involved in the hydrological sciences graduate program at the University of Nevada, Reno.

He was born in Athens, Greece, received his doctorate in civil engineering from Stanford, speaks seven languages and drinks Las Vegas tap water when at home and bottled water when at work.


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