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Site Investigation Work Plan-Second Revision Raymond Investment Cotpoalion Former Helena Chemical Facility Page 8 results,Table A,Appendix B. Boring B41 will be advanced to a depth of approximately thirty-five feet to provide vertical definition below the area where previous investigations have indicated that soil has been impacted by nitrates. Soil samples will be collected at depths of 2, 3 (a duplicate), 5 and 12 feet, then at five foot intervals from a depth of 20 to 35 feet, where both a soil and groundwater sample will be collected. Samples were collected at the surface and depths of 1, 3, and 5 feet below the surface during previous investigations,Table D, Appendix B. Condor proposes to collect samples at depths of 2, 5, and 12 feet below the surface during this investigation, except at B41. A total of forty-two (42) soil samples and eight (8) groundwater samples will be collected from the fourteen (14) borings and submitted to a California certified laboratory for analyses. The approximate boring locations are shown on Figure 2 — Site Map with Proposed Boring Locations, Appendix A. An additional sample will be collected from the pond area. The pond sample will be a grab water sample collected using a bailer or dipping cup. If water is not available from the pond,then a soil sample will be collected. 6.0 SOIL AND GROUNDWATER ANALYSIS AND DISPOSAL The fifty one(5 1)soil and groundwater samples will be analyzed for TKN, Ammonia, and Nitrate. Seven (7)of those samples collected from locations B37 and B38 will also be analyzed for OCPs, hydrocarbons, and metals.B37 and B38 are near the location where materials handling violations were recorded in 2006. The additional laboratory analysis near this location appears to be justified because in 2006 removal of materials may have caused soil impact, but no confirmation sampling was documented. The OCP Endosulfan was detected in the waste characterization sample that was analyzed for disposal. Soil samples collected from location B33 will also be analyzed for OCPs, hydrocarbons, and metals as requested in the CVRWQCB letter dated February 6, 2015 due to the proximity to the Former Hazardous Materials Storage Area. The water or soil sample collected from the pond will be analyzed for OCPs, hydrocarbons, and metals as requested in the CVRWQCB letter dated February 6, 2015. A table listing the boring locations, depth of sampling, container type, labeling, preservation method, analytes, and analysis methods is included in the Helena Chemical-Sampling and Analysis Plan Summary Table, Appendix C. The soil cuttings that are not used as samples will be placed in 55-gallon drums, sealed, labeled, and left on Site to await disposal pending results of the laboratory analyses. Borings will be backfilled with neat cement according to San Joaquin County Environmental Health Department procedures. 6.1 QUALITY ASSURANCE/QUALITY CONTROL PROCEDURES All samples will be transported using chain of custody procedures to the laboratory. The samples will be placed in containers with preservative reagents provided by the laboratory. The samples will be transported in coolers filled with ice or an ice substitute to maintain temperatures of four degrees Celsius. The samples will be delivered to BC Laboratories in Bakersfield California,which is a State of California certified environmental laboratory. Quality Assurance/Quality Control(QA/QC)samples will be collected in addition to the primary samples collected and analyzed, as described above. A total of five duplicate soil samples, two equipment rinsate samples and one groundwater duplicate sample will be collected and transported to the laboratory with the other samples under the same chain of custody procedures. The number of soil duplicate samples and groundwater duplicate samples is intended to be approximately ten percent of the total number of primary samples. The number of two rinsate samples was selected because groundwater sample collection using non-disposable equipment is expected to occur over the course of two days. The USEPA has developed guidelines for QA/QC. These guidelines were consulted. However, the guidelines used statistical methods to quantify the number of samples to be collected based largely on the number of samples and non- detections expected. The US EPA QA/QC procedures appeared to be unsuitable for the Site because of the wide difference between the presence of nitrates and the lack presence or data related to the new n ILA CONDOR