Stringfellow Site - Glen Avon, California

Glen Avon, California

The Stringfellow Hazardous Waste Site is located within the Glen Avon Basin, a segment of the Chino groundwater basin, in Riverside County, California, approximately 50 miles east of Los Angeles. The original disposal area is located at the head of Pyrite Canyon in the southern portion of the Jurupa Mountains where five hydrostratigraphic units have been identified onsite. The disposal area was operated as a Class I industrial waste disposal facility from 1956 through 1972 on land owned by the Stringfellow Quarry Company. Approximately 34 million gallons of industrial process wastes containing spent acids and caustics, solvents, pesticide by-products, metals and other inorganic and organic contaminants were discharged into evaporation ponds onsite during this period. Because the site is geographically separated into four contaminant zones, site characterization, groundwater modeling, and development and implementation of remediation plans required careful attention due to the hydrologic, geographic, and contaminant complexities at this site. The primary contaminants of concern included TCE, chloroform, nitrates, and sulfates.

SSP&A acted as principal technical advisor on groundwater issues, oversaw field investigations, and evaluated remedial activities. SSP&A was initially retained as groundwater advisor by the Possible Responsible Parties (PRP) group to respond to the California Department of Health Services' contractor’s Remedial Investigation/Feasibility Study (RI/FS). Based on a review of the RI/FS and supportive data, SSP&A was able to demonstrate that the FS groundwater remediation plans were not feasible. SSP&A’s role was expanded to include conducting a feasibility study to identify potential remediation alternatives; conducting hydrogeologic investigations; performing flow and transport modeling; providing expert testimony regarding the nature and extent of site contamination and investigative programs; participating in technical presentations to the PRP group and government agencies; and providing oversight and evaluation of continuing work performed by state agencies. SSP&A developed alternative groundwater remediation scenarios for both on-site and off-site contamination. Remedial measures included groundwater extraction (onsite wells and drains), onsite pre-treatment of metals and organics followed by treatment in Orange County POTW and discharge into the Pacific Ocean.

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