The state agency tasked with regulating hazardous materials should reject Stanford University's plan to deal with trichloroethylene (TCE) under 1601 California Ave., a College Terrace Residents' Association subcommittee studying the site has told the Department of Toxic Substances Control (DTSC).
Stanford recently found the hazardous TCE vapors in the middle of its University Terrace construction site in the Stanford Research Park, which is slated to become 180 homes. The discovery caused Stanford to alter its building plans, moving a number of residences from atop the most contaminated "hot spots" to another location on the property. The university also proposes to cap some of the TCE areas with roads, add vapor barriers to new homes to prevent TCE seepage, and not build on some areas of the property.
TCE, which is most often used as a degreaser for industrial use, has been linked to kidney, liver and cervical cancers, according to the U.S. Environmental Protection Agency.
Members of the subcommittee for College Terrace, which lies across California Avenue from the construction site, include a research chemist, a NASA environmental scientist and a toxic-vapor-control expert. In a Jan. 26 letter, the neighborhood association stated that it wants the state department to require Stanford to remove the contaminated soil and take other safety measures. The residents are concerned that TCE may be migrating or will migrate into the groundwater during rains or that it could be in the soil under their homes. Stanford has not tested for TCE along the site's border closest to their neighborhood along California Avenue nor in College Terrace itself, they said.
But Stanford denies that the underground TCE is a problem for College Terrace. The TCE soil levels are below limits for residences, they said in an email to the Weekly.
"The site investigation and testing demonstrates that the TCE in the soil vapor would not contribute to TCE in groundwater, and there is no presence of TCE in surface soil that would cause contamination of rainwater runoff," Stanford spokeswoman Jean McCown said on behalf of the university's project team. "There is no TCE in soil, at any depth, above residential screening levels. There is TCE in soil vapor only and it is limited to the area under a prior building location."
But upon hearing of the TCE discovery, the neighborhood association reviewed a hazard-assessment plan and other documents by Stanford and its consultants and launched its own evaluation. College Terrace association Vice President Ed Schmitt, a retired research organic chemist and polymer scientist, took the TCE locations maps made by Stanford's consultants and studied the relationships of the areas deemed unacceptable by the consultants.
While Stanford's FAQ sheet states that TCE is contained in well-defined, isolated locations, Schmitt said the areas, based on the consultant's data, "are not so well-defined. They are not so isolated and it spills over onto the other property" at 1501 California Ave., which is adjacent to the contaminated area. The 1501 site is also part of the redevelopment project. About 15 homes on the 1601 Stanford site would also still be touching high-concentration areas, Schmitt said the data show.
During a CTRA board meeting on Wednesday night, Schmitt said residents are concerned that rainfall moving water downhill might move TCE to a collecting pond that Stanford is planning. The man-made ravine would send water over one of the highest concentrations points of TCE, he said.
"TCE generally travels in soil or soil vapor in a radius from a source, we were informed at the Jan. 6 meeting (with DTSC Hazardous Substances Engineer Jovanne Villamater). So it appears quite implausible that a spill emanating from a high concentration spot on the 1601 California Ave. site would be suspected of leading to elevated TCE levels several hundred yards away on the 1501 California Ave. site, but not anywhere in much closer to College Terrace," the group wrote to DTSC.
TCE vapors can also cause a risk through indoor air, which has prompted Stanford's proposed addition of vapor barriers. But homes in the College Terrace neighborhood are not equipped with vapor barriers nor any other protective measures, the association stated.
The College Terrace Residents' Association wants the state agency to require monitoring of the border of Stanford Research Park at California Avenue by taking measurements over the foundations of 13 new homes that will face California Avenue.
Regarding the possible movement of TCE in groundwater, if it is present and cannot be removed, the association asked the state agency to come up with mandated strategies to deal with it, such as soil and groundwater removal.
A Jan. 25 report by the watchdog group the Center for Public Environmental Oversight regarding the 1601 California contamination supports the residents' positions. More groundwater testing should be done, the report concluded.
"College Terrace may be subject to vapor intrusion from contaminated groundwater flowing from across California Avenue," Executive Director Lenny Siegel, an expert in toxic-vapor control, wrote.
Stanford's 1601 Risk Assessment notes that the area along California Avenue has subsurface meandering water channels, which indicate that it is possible for contamination to have migrated hundreds of feet from the contaminated source areas.
Some attempts to locate groundwater contamination at 1601 California have come up dry, but Siegel said that does not mean contamination hasn't migrated. Chemical movement may have occurred during wetter years, and collection attempts may have missed the subterranean channels.
"Sampling at 1501 California, just to the north, found groundwater between 30 and 55 feet beneath the surface," he said.
Siegel said that at a Mountain View Superfund site with similar pollution plumes, the adjacent residential area was not initially monitored. But unacceptable levels of TCE vapor were found inside a resident's home in 2002. In 2013, two more homes required cleanup in the same neighborhood after denser groundwater monitoring was conducted, Siegel said.
"The protective approach would be to install groundwater monitoring wells along California Avenue and/or conduct indoor air sampling in nearby homes," he concluded. "I don't want to panic people. I don't think vapor intrusion in College Terrace is likely. But thus far not enough has been done to rule it out."
But Stanford argues that the state agency has already said the university's plans are adequate.
"DTSC, the regulatory agency with the authority to approve the proposed actions, has concluded that given the measures proposed by Stanford, there is no significant exposure risk to future site users," McCown said.
She added that the university would have a comprehensive response to the questions posed by the College Terrace and Siegel letters to the DTSC within the next couple of weeks.
"All of the questions can be answered based on data and assessments in the extensive investigation and risk assessment report previously provided to DTSC," she wrote.
DTSC spokesman Russ Edmondson said the agency is in the process of reviewing the College Terrace association's comments and will respond.
"To this point, no conclusions have been made regarding the site," he wrote in an email.
Other locations in Stanford Research Park where contamination has been found include the former Hewlett-Packard sites at 620-640 Page Mill Road, which were designated a Superfund cleanup site; the former Varian Medical Systems, Inc. at 601 California Ave. and the former HP facility at 395 Page Mill Road. An underground plume of heavy metals and hazardous chemicals known as volatile organic compounds (VOCs) formed under these sites. The plume affects groundwater under parts of the Research Park, the Stanford/Palo Alto Community Playing Fields, Palo Alto Square, Fry's Electronics and the Palo Alto Courthouse, according to the 2010 California Regional Water Quality Control Board report.
Schmitt noted that at the HP sites, Stanford remediated the hazards.
"Stanford has put in the effort to rid the area of polychlorobiphenyls or PCB. They did remove 130,000 tons of dirt in which the PCB was adhered. They don't seem to be putting in the same level of effort to marginalize the TCE contamination," he said.
Stanford, however, maintains that the exposure risk is not the same and does not require the same treatment.