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a' RECEIVED 11 April 2016 AGE Project No. 16-3650 JUN 3 Q 2016 Page 2 of 4 ENVIRONMENTAL HEA!TH D-R^77'IFNT Health Department (EHD) and encroachment permits from the City of Manteca Public Works Department. In addition, a health and safety plan will be updated in accordance with Occupational Safety and Health Guidance Manual for Hazardous Waste Site Activities (National Institute for Occupational Safety and Health Administration, U.S. Coast Guard and U.S. Environmental Protection Agency, 1985). Prior to mobilization, each proposed boring location will be clearly marked, and utility clearance will be obtained through Underground Service Alert. 2.2. CONE PENETROMETER TEST Utilizing a 25-ton truck-mounted CPT drill rig equipped with 13/4-inch diameter hollow- stem rods, AGE proposes to advance four CPT soil borings to help define the vertical and lateral extent of groundwater contamination toward the west, northwest and north. AGE proposes to advance the CPT soil borings to depths of approximately 115 feet below surface grade for sampling based on the dissolved hydrocarbon impact encountered in previous site assessment data. The soil borings will be advanced at the following locations (Figure 2): • CPT boring P-11 will be located approximately 300 feet west-northwest of the site to define the cross-gradient lateral and vertical extent of hydrocarbon- impacted groundwater; • CPT boring P-12 will be located approximately 360 feet northwest of the site to define the down-gradient lateral and vertical extent of hydrocarbon-impacted groundwater); • CPT boring P-13 will be located approximately 525 feet northwest-north to define the down-gradient lateral and vertical extent of hydrocarbon-impacted groundwater; and • CPT boring P-14 will be located approximately 350 feet north-northwest of the site to define the cross-gradient to downgradient lateral and vertical extent of hydrocarbon-impacted groundwater. Each of the proposed CPT locations (P-11 through P-14) will consist of multiple 13/4-inch boreholes. Based on the CPT logging data previously acquired from P-7 through P-10 (Appendix B), only the first CPT boring advanced during this investigation (P-11) will utilize cone penetrometer testing for logging purposes. A continuous lithologic CPT boring log will be acquired from P-11 to confirm the stratigraphic and hydrogeologic units. Based on this interpreted lithologic data and assessment needs, additional 1 3/4- inch soil borings will be advanced in the P-11, P-12, P-13 and P-14 areas to acquire independent grab groundwater samples in each targeted zone. Each CPT boring will be advanced to total depths of approximately 115 feet bsg; however, the total depths of borings may vary according to hydrogeologic conditions encountered during drilling Advanced GeoEnvironmental,Inc.