Committee to Bridge the Gap



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Runkle Ranch is the site of a proposed residential development in Simi Valley. Because it is located near to, and below, the Santa Susana Field Laboratory ((SFL), a nuclear reactor and rocket testing and development facility with significant radioactive and chemical contamination, the developer arranged for a series of tests of soil and other environmental media. SSFL is operated for the U.S. government by the Rocketdyne Division of the Boeing Company. This report examines the results of the soil testing for radioactivity.

The Environmental Impact Report (EIR) that supported the approval of the project briefly addressed the potential for contaminants from SSFL to have impacted the Runkle Ranch land and concluded that this was not an issue. The EIR1 noted that background levels of strontium-90 are “about 0.1 pico Curie per gram (pCi/g)” and went on to describe sampling results for the Runkle property:

"Previous assessments of strontium-90 and tritium within the vicinity of the [Runkle Canyon] Specific Plan Area included a survey conducted by QST Environmental, Inc. in 1998. This study was conducted to determine if nuclear 1 This and the following two quotes are from pp. 4.6-6 and 4.6-7 of the EIR. 2 reactor operations at the SSFL facility had impacted soil at the site through surface water runoff. Four soil samples at three were collected and analyzed for cesium-137, strontium-90 and tritium. One of the locations was within a natural drainage channel flowing from the locale of the SSFL facility towards the northeastern portion of the Specific Plan Area. The results of the survey indicated that the surface soil contained concentrations of cesium-137 and strontium-90 that exceeded background levels established by the EPA."

Because of the initial findings, followup sampling was initiated. As the EIR states:

"Consequently, further testing was indicated. Tritium was also detected in the samples, but at concentrations below the EPA background levels. A limited radiation survey was conducted during subsequent testing and analysis in the Phase I ESA for the 550-acre parcel referenced in this section. This assessment found that radiation levels were within normal background levels. Tritium and strontium-90 were not detected in any of the soil and groundwater samples at levels above normal background levels or at levels considered to pose a health risk. (emphasis added)."

This conclusion is puzzling, because the actual measurements being cited for the proposition that none were above background nor above levels considered to pose a health risk show precisely the opposite. Rather than none of the samples being above background or health risk levels, ALL 58 of the 1999 follow-up strontium measurements exceeded the 0.1 pCi/gram background figure cited in the EIR (as we shall see, that figure is actually twice background), and virtually all exceed the EPA’s Preliminary Remediation Goals (PRGs).

This research was completed money allocated during Round 6 of the Citizens’ Monitoring and Technical Assessment Fund (MTA Fund). Clark University was named conservator of these works.

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Committee to Bridge the Gap




nuclear weapons, nuclear weapons testing, environment, non-governmental organizations, United States Department of Energy, tribal governments, environmental cleanup, radioactive fallout, radioactive waste


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Santa Cruz, CA

Radioactive Contamination at Runkle Ranch from the Santa Susana Field Laboratory



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