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Department of Ecology News Release - March 20, 2001
01-042
OLYMPIA - A just-released study by the Department of Ecology (Ecology) has confirmed that elevated levels of arsenic have been found in residential soils in Pierce County's University Place.
The study showed that 60 percent of the 59 residential yards sampled contained arsenic at more than 20 parts per million (ppm). State cleanup standards call for achieving levels below 20 ppm.
The average concentration of arsenic contamination was 26.4 ppm. In 80 percent of all the yards sampled, arsenic was below 40 ppm.
Samples were taken from each yard at depths of zero to 2 inches, 2 to 6 inches, and 6 to 12 inches. The maximum concentration of arsenic found was 163 ppm in the top two inches at one property. Arsenic concentrations are lower at properties of newer residences, probably because of more recent soil disturbances due to grading and landscaping.
The study also evaluated lead. It was not found to be above the state cleanup standard of 250 ppm.
The source of the arsenic is believed to be the now-closed Asarco copper smelter that operated in Ruston from 1890 to 1986. Arsenic, lead and other heavy metals were likely carried by wind and deposited throughout central Puget Sound. The smelter and surrounding property were declared a federal Superfund cleanup site in 1983.
"We are thankful the levels of contaminants do not constitute an imminent public health threat at University Place or in King County," said Marian Abbett, who is managing the arsenic study for Ecology. "But we are greatly concerned about the public's persistent exposure to low levels of arsenic and lead over a long period of time."
Abbett said the contamination probably is not confined to University Place. Her department plans to expand its assessment of arsenic contamination throughout Pierce County.
The study adds to experts' knowledge about how much area the Tacoma smelter may have contaminated. Late last year, a study conducted by Ecology and the Seattle/King County health department found arsenic and lead contamination on Vashon and Maury islands, and in some parts of mainland King County. Arsenic levels found in University Place soils are comparable or somewhat less than levels found on Vashon and Maury islands.
Ecology is working closely with the local health departments in both King and Pierce counties to address the soil contamination in their jurisdictions.
Ecology's sampling study of residential soils in University Place was sparked after soil samples collected by the Tacoma Water Department revealed elevated arsenic and lead in undisturbed areas of that city, including parks and undeveloped properties.
"Normally, we're working on cleanup sites that we can measure in square feet, yards or acres - not miles. This is a huge area of soil contamination, the largest one the Department of Ecology has ever addressed," Abbett said.
Ecology is developing a public involvement plan to keep people in Pierce County informed about the progress of the expanded arsenic-lead sampling. For more information, visit the Web sites below or contact Molly Gibbs at Department of Ecology, 360-407-6179, or e-mail her at mgib461@ecy.wa.gov.
Contacts: Sandy Howard, Department of Ecology, 360-407-6239; pager,
360-786-3136
Steve Marek, Tacoma-Pierce County Health Department, 253-798-2955
Copyright © Washington State Department of Ecology. See http://www.ecy.wa.gov/copyright.html.
