--> Abstract: Background Concentrations of Metals, Guadalupe River Drainage, Santa Clara County, California--Regulatory Implications, by G. A. Jett and C. Kennedy; #90958 (1995).

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Abstract: Background Concentrations of Metals, Guadalupe River Drainage, Santa Clara County, California--Regulatory Implications

Guy A. Jett, Christina Kennedy

The California Code of Regulations lists 17 metals which are presumed to create a toxic hazard when their concentrations exceed certain listed values (the "STLC" and the "TTLC"). In practice, when a reported concentration exceeds the "STLC" by 10-times the "STLC" value, the sample must be reanalyzed to assess the potential for toxic concentrations to be dissolved from the material and moved into the environment. Such assessments are, among other conditions, to be completed prior to disposal.

Kleinfelder, as part of an assessment along a 5-mile reach of the upper Guadalupe River, collected and analyzed 65 soil samples from 10 randomly selected locations within the limits of a flood control project. Comparison with other "background" data (CM Scott, CSU, San Jose, Master's Thesis, 1991) indicates substantially higher average concentrations in this area for arsenic, chromium, mercury, nickel, and vanadium. Of special note, the average concentrations for chromium (135 mg/kg) and mercury (3.2 mg/kg) substantially exceed their respective 10-times STLCs (50 mg/L and 2.0 mg/L). These results should be taken into consideration whenever soils from the Guadalupe River drainage system are assessed relative to regulatory standards.

AAPG Search and Discovery Article #90958©1995 AAPG Pacific Section Meeting, San Francisco, California