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Nevada researchers hot on the trail of arsenic dilemma in Churchill County

By Bob Conrad and Melanie Supersano

Mark Walker is tracking down arsenic. He doesn't have to look very far. Many private water supplies in Churchill County contain arsenic levels 100 times higher than the federal standards set for public water supplies.

Walker, a professor of environmental and resource sciences within the College of Agriculture, Biotechnology and Natural Resources, and state specialist with University of Nevada Cooperative Extension, is analyzing data gathered from water-quality sampling surveys in a project he initiated in 2001. In Churchill County, 4,500 private wells supply water to nearly half of the county's 23,000 residents. Unlike public water supplies, private wells in rural areas are not regulated. As a result, rural water wells may supply water high in naturally occurring contaminants like arsenic.

"Results of our efforts indicate that arsenic concentrations in private water supplies are highly likely to exceed 10 parts per billion — the new standard for drinking water," Walker says.

As part of the project, Douglass Shaw, associate professor of applied economics and statistics, helped develop a survey that determines how people react to the risk of drinking water with arsenic in it. The survey shows that a large fraction of private well owners consume the water in spite of having information about the likelihood of high arsenic concentrations.

"We found that factors contributing to consuming water high in arsenic include age and time as a resident in the county," Walker says. In other words, the longer a resident has lived in Churchill County, the less concern there is about potential risks involved with consuming water with high arsenic levels.

A paradox exists, however, because residents want to know: What are the long-term health effects of arsenic exposure, if any? At high levels, arsenic poisoning can cause destruction of red blood cells, kidney damage and in chronic exposure, gradual loss of strength, diarrhea or constipation, paralysis and confusion, degeneration of fatty tissue, anemia, and characteristic streaks across the fingernails. At low levels over long periods of time, arsenic may cause internal organ and skin cancers, among other illnesses.

"Fallon represents a unique opportunity to answer questions that may give us insight into what happens to people in a U. S. population who have had long-term exposure to arsenic in their water," explains Rebecca Calderon, the Environmental Protection Agency's chief of epidemiology and biomarkers in its Office of Research and Development. It is the largest study of its kind in the United States. Over 900 Churchill County residents participated.

"The response from the people in Churchill County was impressive, both from people who are concerned about arsenic's potentially harmful effects and those who think there might not be any effects," says Pamela Powell, extension educator. Powell has joined Walker and the Cooperative Extension Nevada GOLD (Guarding Our Local Drinking Water) volunteers in helping to interpret water test results.

"The information from these efforts will meet growing concerns about the county's water quality," Walker says, "especially among private well owners who are not protected by state and federal standards."


Arsenic quick facts:

  • Arsenic is a semi-metallic element.
  • Arsenic is poisonous because it interferes with cellular metabolism.
  • Arsenicals are used in numerous beneficial products, including insect, rodent, and weed killers, some chemotherapeutic agents, and certain paints, wallpaper, and ceramics.
  • An arsenic preparation was the first drug used to kill syphilis germs.
  • Criminal use of, or accidental exposure to arsenic can now be determined by finding forensic evidence in urine, hair or nails.
  • The treatment of acute arsenic poisoning involves washing out the stomach and the prompt administration of dimercaprol.

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