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Geological Technics Inc Page 2 <br /> Ripon Milling Inc <br /> • Report-Groundwater Investigation <br /> Project No 253 2 <br /> July 31,1995 <br /> aromatic petroleum hydrocarbon compounds were detected in both rounds of <br /> groundwater samples. <br /> 1.0 GROUNDWATER INVESTIGATION <br /> 1.1 Drilling and Monitoring Well Installation <br />' To further investigate the extent of diesel range petroleum hydrocarbons in the soil <br /> and groundwater environments, Geological Technics Inc installed one groundwater <br /> monitoring well (MW-1) in the suspected down gradient direction from the point of <br /> release (as determined by the SJCPHSEHD) MW-1 was installed outside of the <br /> former excavation lust north of where the deepest and highest concentration of <br /> diesel was once located (Figure 2 Site Map) <br /> The well boring was drilled using a 10 25 inch outside diameter continuous flight <br /> hollow stem auger owned and operated by V&W Drilling (C57# 658786) Soil <br /> cuttings were added to the existing stockpile on site within the fenced yard and <br /> • underlain and covered with plastic <br /> Soil samples were collected for geological and analytical evaluation at five foot <br /> p g g Y <br /> intervals A boring log providing sediment description using the U S C S and field <br /> observations was maintained by a professional geologist working under the <br /> supervision of a registered geologist Soil samples were collected in 6 0 inch brass <br /> liners using a 2 0 inch modified California split spoon sampler All soil samples <br /> were sealed with aluminum foil, capped, labeled and placed in a cooler at 4° Celsius <br /> for transport to the laboratory following Chain of Custody protocol <br />' Based on sediments recovered in the split spoon sampler the soil profile of MW-1 <br /> was observed to generally consist of sand with varying amounts of silt and clay <br />' matrix The soil at 15 feet below grade was observed to exhibit a slight diesel like <br /> odor Saturated sediments were encountered at approximately 30 feet (the water <br /> table stabilized at approximately 26 feet after well development) The MW-1 boring <br />' terminated at 42 feet where a very hard cemented sand was encountered The <br /> boring log for the MW-1 boring is attached in Appendix C <br /> Because every soil sample collected was not submitted for laboratory analysis, a <br /> screening process was used to gather additional information through field <br /> observation noting sediment type, especially grain size and clay content, moisture <br />' content, visible evidence of contamination, i e , color change due to reduction of iron <br /> or discoloration from hydrocarbons and other pollutants, and the readings above <br /> background on a organic vapor meter (OVM) The OVM is a field portable photo <br /> I <br />