TOSC Assists San Martin, a California Community Affected by Perchlorate in Groundwater

Recently, TOSC began working with San Martin, a rural community about 30 miles south of San Jose that is facing widespread groundwater contamination. Most of the residents in this town of 12,000 draw their water from private wells. This Spring, residents learned that their aquifer is contaminated with perchlorate, a chemical used to manufacture rocket propellants, explosives, fireworks and flares.

Perchlorate is a salt that is easily dissolved and transported to groundwater and when consumed can interfere with functioning of the thyroid gland. The contamination in San Martin has been traced to a flare manufacturing facility on the southern edge of neighboring Morgan Hill where contaminated soils have been found. Of the 1054 wells tested as of May 2nd, 38% have levels of perchlorate at or higher than the action level of 4 ppb set by the California Department of Health Services.

Links to San Martin Information: Map of Contaminated Well sites, produced by the Santa Clara Water District (in pdf format). San Martin Neighborhood Alliance website. Recent news story in the Pinnacle. Santa Clara Valley Water District perchlorate website.

Shortly after news of the problem was made public in March, TOSC contacted the San Martin Neighborhood Alliance to offer technical assistance. This group worked with the California Regional Water Quality Control Board and the Santa Clara Valley Water District to form an ad hoc citizen’s advisory group now known as the Perchlorate Citizen’s Advisory Group (PCAG).

During April, the PCAG asked TOSC for technical reviews of two documents submitted to the Regional Water Quality Control Board by the environmental consultant engaged by the property owner. One is a cleanup plan for the soil contaminated by perchlorate, the other is an evaluation of possible cleanup technologies for the contaminated groundwater. TOSC was asked to review the documents and summarize them for the community in a concise and easily understandable format.

At the second PCAG meeting held at the beginning of May, TOSC presented PCAG with simplified interpretations of the consultant’s reports that are suitable for distribution throughout the community and a chart explaining the groundwater cleanup technologies. The chart will be used at future community-wide meetings. The PCAG also requested an in-depth review and critique of the consultant’s soil cleanup plan.

TOSC will continue to provide the PCAG with technical assistance and information about groundwater and soil contamination issues and will attend community meetings when appropriate. upcoming issues for the community include the effects of perchlorate contamination on produce and livestock and a discussion of various plans to bring safe drinking water back to the community.

If you would like additional information about TOSC's work with San Martin, please contact Jerry Orlando at jerry.orlando@ orst.edu or 541-737-5736.