Publication Date: Friday, June 25, 2004
Toxins found west of Whisman Road
Toxins found west of Whisman Road
(June 25, 2004) EPA plans to survey homes beyond MEW boundaries
By Jon Wiener
Local residents recently learned the Middlefield-Ellis-Whisman (MEW) Superfund site does not stop at Whisman Road. Last week, a representative from a company responsible for the pollution tried to assure them that the toxic plume is not expanding.
The most recent maps made available by the EPA show trichloroethene (TCE) contamination in ground water beyond Whisman Road, previously recognized as the westernmost boundary of the site. In March, the U.S. Environmental Protection Agency (EPA) discovered vaporized TCE, a cancer-causing solvent, in one of four homes it tested on the west side of the street.
At the May meeting of the Northeast Mountain View Advisory Council, residents of the area voiced their concerns about evidence showing the contamination to be spreading. But on June 16, a consultant for Fairchild Semiconductor came to the citizens group meeting to attempt to definitively address those concerns.
"The plume boundaries are not expanding. They've been stable for at least the last 17 years," said Maile Smith. In fact, said Smith, concentrations of TCE have actually decreased 75 percent throughout the site since clean-up efforts began in 1997.
The maps originally published by the MEW companies last year -- drawn from data taken from hundreds of wells throughout the site -- showed the western boundary of the plume extending beyond Whisman Road. Smith said contamination levels have not changed significantly in any of the wells near the residential area, but that the companies' interpretation of existing data changed.
The MEW companies will release another set of maps by July, with new data from 2003-2004, added Smith.
The agency tested four sample residences on the western side of the street in March. Tests revealed significant concentrations of TCE and other chemical vapors in one home with an earthen cellar, according to Alana Lee, EPA project manager for the MEW site.
In the coming weeks, the EPA will be surveying residents west of Whisman Road about their foundations and looking for more volunteers to have their homes tested for TCE vapors. Lee has already heard from one resident who would like to volunteer.
The goal of the survey is to find out more about the structure of homes in the area and find more people willing to have their homes tested.
The EPA is not ready to recommend a certain type of construction to prevent vapor intrusion, as requested by Mountain View residents, but the agency's efforts will focus at least in part on homes with earthen cellars, said Lee.
"Because we saw it in this one home, it does raise the possibility that we will see higher concentrations in those," said Lee.
Lee is also seeking feedback on the draft of the EPA's five-year report on the site. The report is available on the NMAC Web site (www.nmac.whisman.net) and open for public comment until July 15. The final report is due in September. As of press time, Lee said she had not received any feedback yet, but expected to get some at an NMAC workshop at Whisman Station on June 23.
Residents who wish to volunteer for testing in their homes can call Alana Lee at (415) 972-3141.
E-mail Jon Wiener at [email protected]
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