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contribute to ground -water contamination, including leaking underground storage tanks, agricultural activities, dairies, septic systems, and storm water infiltration. Agricultural activities and the use of septic systems in the area are known ground -water contamination sources with the potential to impact the Site. Two common ground -water contaminants in San Joaquin County are nitrate and dibromochloropropane (DBCP). Live Oak reviewed the San Joaquin County Environmental Health Department's maps of Nitrate — Land Use Data and DBCP— Land Use Data dated February 20, 2019 (Plates 6 and 7). According to the nitrate map, seven wells within a one -mile radius of the subject Site have been tested for nitrate; nitrate was detected in four of the wells at concentrations between 0.1 and 5.0 mg/L-N, and in three of the wells at concentrations between 5.1 and 10.0 mg/L-N. According to the DBCP map, seven wells within a one -mile radius of the Site have been tested for DBCP. No DBCP was detected in three of the wells; DBCP was detected over 0.2 [g/L in the other four wells. On -Site Wells Two public water wells are located on the Site. A Technical Report prepared by Quality Service, Inc. for the II Vineto Mobile Home Park and provided by Mr. Wert described the proposed construction of these wells (now complete): "Two (2) new wells are being constructed at this facility to replace the existing wells due to their age, a DBCP MCL violation, as well as 1,2,3 -TCP and Nitrate contamination concerns... Both wells are to be drilled to 510 feet and have a cement seal to 220 feet." Mr. Wert indicated that the two older wells were destroyed and filled with slurry, according to the park manager. The Quality Service report states that the water system "features a Granular Activated Carbon (GAC) filtration system designed to remove 1,2,3 -TCP... Quarterly sampling in the effluent water from this treatment system indicates that these filters have been effectively removing DBCP from the [then] utilized water sources... Analytical results from the newly constructed sources shows compliant water quality that will not require treatment. However, the current treatment system at this facility will still be utilized and maintained to help provide the highest quality water to the residents of this park." Five well permits were identified for the Site from among the files of the San Joaquin County Environmental Health Department: • April 1988 permit for new public well. The grout seal was placed at a depth of 50 feet. The permit notes, "old well to be removed within 30 days of pump removal." • August 1988 permit for destruction of old well. The permit depicts the old well, a new well, and an "existing well." • August 1990 permit for system repair at well. LOGE 2218 Page 4