Sacramento Bee - August 29, 2004 (notes from the article)
Scientists have reported elevated levels of asbestos in the lungs of pets from western El Dorado County, where development has unearthed the naturally occurring minerals. The sample size is small - four dogs and cats - but officials said the results bolster their plan to investigate whether area residents are exposed.
At recent EPA forums, residents asked whether they endangered their health by living in El Dorado County. There are no black and white answers. They hope to move forward by finding out how much asbestos residents are breathing during their everyday lives.
The four pet's lungs were loaded - with the most asbestos fibers, up to 9.2 million per gram - found in a male dog. An expert, said the lungs of dogs are generally "dirtier" than human lungs, as dogs sniff the ground. They therefore make better asbestos sentinels for humans. Results show elevated lung burdens of the tremolite/actinolite type of asbestos in the dogs but the number of studies on dog lungs are too few for comparison.
For years, the dog's owner fought to contain the asbestos dust on his 10-acre spread and said he saw no way out but to let the bank repossess the seven-bedroom home he built. His couch cat who died of old age, also retained amphibole fibers, an estimated 86,000 to 157,000 per gram. The other dog owner learned that his dog's lungs had up to 1.25 million tremolite- actinolite fibers lodged in its breathing tissues.
Scientists have yet to define dangerous levels of exposure. The recipe for disease is complicated. Fiber dimensions and concentrations, exposure frequencies and durations, smoking history and other conditions all factor into the equation. No standard methods have been established for the exposures in the foothills and other areas where naturally occurring asbestos has been disturbed but experts agree that the fibers found in the four pets are more potent than the chrysotile kind in causing mesothelioma. No studies have shown a link between disease and exposure to naturally occurring asbestos, but studies elsewhere have shown strong correlations.
For now, the EPA is trying to get a better read on people's exposures to asbestos fibers and outlined a series of air-testa planned this fall in El Dorado Hills at Jackson and Silva Valley elementary schools and Rolling Hills Middle School, the Community Center and the New York Creek nature trail.