Residents in the Prospector area have lower than national average levels of lead in their blood, an Environmental Protection Agency study shows.
Residents in the neighborhood contaminated with old silver mine tailings were told at a public hearing Wednesday night that the lead, arsenic and cadmium in those remains were not contaminating their blood streams."No blood test showed any evidence of lead toxicity," said Michael McGeehin, a toxicologist for the federal Agency for Toxic Substance and Disease Registry.
"All the arsenic and cadmium levels were found to be within the World Health Organization's reference range," McGeehin told the audience of 55 people.
Four of 127 participants in the study had elevated blood lead levels. But a second component that actually measures whether blood has been poisoned was not higher than average in any of the four.
McGeehin said researchers were surprised to find the Park City levels were lower by half than the national average. Residents living in homes built on tailings averaged 7.8 micrograms of lead, whereas the National Health and Nutrition and Examination Study put the U.S. average at 15.
Even more surprising, he said, was the control group in the Holiday Ranch section of Park City, located about a mile away, where averaged blood lead levels are about one-fourth those the rest of the nation.
McGeehin explained one reason for such low levels, compared to the national averages, is that "the human uptake of heavy elements may be less likely when these contaminants are present in mine tailings."
But McGeehin cautioned residents about growing vegetables and fruits in their yards, saying the plant roots can pick up cadmium from the tailings still under the topsoil.
Data collection for the Prospector Square area began in early 1987 after comments from a senior EPA official compared the site to Love Canal.
The site was proposed for Superfund cleanup in 1984, only to be taken off the listed in 1985. It was proposed again in 1986, and removed from the list in 1987.
The EPA announced in 1987 it would do one final study and has been collecting surface and ground water samples, indoor and outdoor air samples, and soils and tailing cores the last 12 months.
Those biological health results released Wednesday had been validated and reviewed by scientists at four universities, McGeehin said.
Results of air sampling will be available to the public by the end of July, and water data will be released publicly sometime in September.