Laserfiche WebLink
1 <br />' Closure Report May ay 21 1993 <br /> Southland Site No 20680, 9110 Thornton Road, Stockton, CA B <br /> the shallowest and deepest soil samples for that boring were analyzed for BTEX and TPH-G If three <br />' or fewer samples had PID readings over 10 ppm, the sample with the highest PID reading was <br /> analyzed If the PID detected no organic vapors, one randomly chosen soil sample was analyzed <br /> Duplication of sample depths for individual borings was avoided The soil sample selection and <br />' analyses procedures were presented in Groundwater Technology's May 5, 1992, Proposal for Site <br /> -Cleanup Confirmation <br /> 4.0 SITE CONDITIONS AND FINDINGS <br /> 4.1 Hydrogeology <br /> Since 1986, the predominant groundwater flow direction has been to the east During the past six <br /> years, the groundwater gradient has fluctuated between an east-northeast and east-southeast <br />' direction The water-table level at the site has dropped from 30 feet below grade in May 1986 to a <br /> low of approximately 50 0 feet below grade in December 1992 Groundwater was encountered at <br /> 49 5 feet below grade in Soil Boring C on January 14, 1993 Groundwater levels measured In <br /> monitoring wells on April 2, 1993, indicated an average water-table elevation of -31 86 feet relative to <br /> msl A potentiometric surface map was prepared using the water-level data collected on April 2, <br /> 1993 (Figure 7) On April 2, 1993, the groundwater gradient was toward the southeast at 0 003 foot <br /> per foot <br /> 42 Analytical Results for Soil <br /> I <br /> The analytical results of soil samples collected during soil boring activities between January 12 and <br /> 14 and February 18, 1992, reported TPH-G and BTEX concentrations below the MDLs in the soil <br /> samples with only two exceptions the samples from Soil Boring C at 35 feet below grade and soil <br /> Ipile SP-1, which were reported to contain 0 071 ppm and 0 02 ppm xylene, respectively <br /> Total lead concentrations ranged from 0 9 ppm in the soil samples collected from Soil Boring B at 25 <br /> feet below grade, to 4 1 ppm In soil samples collected from Soil Boring B at 35 feet below grade <br /> Results of analyses for 1,2-dibromoethane reported concentrations below the MDLs in the samples <br /> collected from the soil borings Analytical results of the soil samples are summarized In Table 3 and <br /> the laboratory reports are Included in Appendix F <br /> 12118013 <br /> _ P GROUNDWATER <br /> - TECHNOLOGY, INC <br />