SR0085490 - Laserfiche WebLink

Home Browse Search

1. Background The Site refers to the 14 acres of land located at 230 Industrial Avenue in Ripon, California where Nestle USA, Inc. (Nestle) had previously manufactured beverage products (Figure 1). Historical Site operations used trichloroethene (TCE)as a decaffeination solvent that was later replaced by methylene chloride. Chloroform was also used on Site for laboratory-scale decaffeination processes (AMEC, 2009). Historical releases at the decaffeination building and industrial sewer leaks have been associated with TCE detections in soil vapor and shallow groundwater samples on Site and west and southwest of the Site. In addition to an extensive groundwater monitoring program and focused areas of groundwater remediation, several rounds of soil vapor extraction were also implemented on and near the Site between 1988 and 1998. Multiple soil vapor investigations have been completed between 1987 and 2008.The focused investigation areas were on Site,the adjacent properties, and/or near 4th Street and Stockton Avenue in Ripon, California. In 2006,TCE concentrations in soil vapor east of Stockton Avenue prompted indoor air sampling at 320 Stockton Avenue;the results of indoor air sampling reported concentrations of Site chemicals of concern (COCs) below health-based screening levels, indicating that indoor air quality did not pose a concern for human health (ECM Consultants, 2009). Additional information on the Site background, historical investigations, and previous remedial actions is provided in the Final Third Interim Report on Soil Vapor and Groundwater Investigations(Third Interim Report; Haley&Aldrich, 2021). In May 2019,the Central Valley Regional Water Quality Control Board (Water Board) requested that Nestle complete an assessment to evaluate whether vapors associated with the Site COCs currently being remediated at the Site could migrate upwards from the subsurface to indoor air by a process called vapor intrusion (VI). Between 2019 and 2020, Haley&Aldrich installed and sampled a total of seventy-three off-Site soil vapor probes to evaluate the potential for VI. The results, conclusions, and recommendations for further assessment were submitted in the Third Interim Report. The investigation results indicated that the vapor intrusion risk was low; however, as a conservative measure,the Third Interim Report recommended continued soil vapor sampling at selected locations, including two rounds of sampling in 2021, and those results are included below. 1 �IBNCH