Passive Air Testing Fails to See Asbestos Contamination During 'Normal' Activities
SACRAMENTO, CA-December 13, 2002-Conventional or passive air sampling methods used to determine exposure to asbestos in El Dorado County, California, may give misleading results, according to Paul Peronard, a top federal investigator in the asbestos-contaminated town of Libby, Montana (Sacramento Bee, December 6, 2002, Chris Bowman). Instead, he advocates "aggressive sampling," in which samples are taken around real or created events that can release asbestos dust into the air. Examples of aggressive sampling include collecting asbestos samples near construction sites, around road-building sites, or where automobiles have kicked up asbestos dust on certain unpaved roads. Typically, the El Dorado samples were taken at a time when no such activities occurred.
Nestled in the foothills of the California Sierras, El Dorado and Placer counties are home to serpentine, a type of rock with a high asbestos content that is found in earthquake fault zones and mountainous regions. Serpentine soil and rock was used in building roads, and may pose health hazards in local gardens, on school grounds, or when it is turned over at home construction sites.
Aggressive sampling may work better than passive sampling to uncover areas where asbestos may be concentrated, according to some scientists and planners. "We're going to bring out the experts from Montana to make sure we're doing the right thing," said El Dorado County Director of Environmental Management, John Morgan, as quoted in the Sacramento Bee. "They're revolutionizing the way you sample for asbestos and assess exposure." Yet California Air Board official Jerry Martin said, "We are not planning on changing our strategy."
Mr. Peronard made his views known at the Naturally Occurring Asbestos Conference, a recent gathering of air quality officials, public health officials, doctors, geologists, engineers, and government representatives. The event was sponsored in part by the American Lung Association of California, the California Conference of Local Health Officials, and the Department of Toxic Substances Control.