Laserfiche WebLink
v <br /> r.r <br /> ATC <br /> A S S O C I A T E S I N C <br /> bgs but the impacted soil appeared to attenuate rapidly with depth. The monitoring well was <br /> developed and a groundwater sample was collected from the well although water was measured_ <br /> to be above the top of the well screen. Analytical results indicated the presence of petroleum <br /> hydrocarbons. Results are summarized in AGE'S Quarterly Report-July 1998. <br /> 2.0 METHODS AND PROCEDURES <br /> To evaluate the extent of impacted groundwater and determine the groundwater gradient at the <br /> site, two soil borings were advanced in the vicinity of the former USTs and completed as <br /> groundwater monitoring wells. All field activities were performed in accordance with ATC's <br /> Workplan for Installation of Groundwater Monitoring Wells at City of Stockton Fire Station <br /> No.3, 1116 First Street, Stockton, California, dated March 3, 1999. This workplan was approved <br /> by PHS/EHD on March 5, 1999 with minor modifications. <br /> 2_1 Soil Boring Advancement and Sampling <br /> Drilling was conducted on March 16, 1999 by V & W Drilling (State C57 license no. 720904) <br /> utilizing a hollow stem auger drill rig. Soil borings MW2 and MW3 were advanced and <br /> completed as groundwater monitoring wells. A field geologist logged drill cuttings and soil <br /> samples utilizing the Unified Soil Classification System. Descriptions of soil types encountered <br /> and sample collection intervals are included on the boring/well construction logs contained in <br /> Appendix A. <br /> The cored soil samples were collected at five-foot intervals or significant changes in lithology <br /> using a 2-inch diameter split-spoon sampler containing three brass tubes. The cored samples and <br /> drill cuttings were characterized for soil type, moisture content, and visual evidence of petroleum <br /> hydrocarbons. A photoionization detection meter (PID) was used as a field screening device for <br /> the detection of petroleum hydrocarbon vapors in drill cuttings and cored samples. Drill cuttings <br /> were temporarily stored on site in 55-gallon DOT approved steel drums. <br /> 2_2 Soil Sample Analysis <br /> Selected soil samples were placed on ice, and transported under chain-of-custody to Sequoia <br /> Analytical (ELAP No.1210) of San Carlos, California for analysis. All soil samples were <br /> analyzed for total petroleum hydrocarbons as gasoline (TPHg), benzene, toluene, ethylbenzene, <br /> and xylenes (BTEX) utilizing EPA 8015 and 8020 methodologies, and oxygenate fuel additives <br /> utilizing EPA 8260 methodology. The analytical results for soil samples are summarized in <br /> Table 1. Laboratory data sheets and chain-of-custody documentation are included in Appendix <br /> B. <br /> w:\16393\reports\sumi.doc 2 <br />