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�.✓ N"0111 5.0 Chemical Analysis Six (6) soil and five (5) groundwater sain.ples were analyzed at Kiff Analytical LLC, a State- certified analytical laboratory in :Davis, California. All samples were tested for the following; Total Petroleum Hydrocarbons as Diesel (TPHD) using EPA Method 8015m. The analyses were performed and a "normal" ten-day turnaround. The analytical reports are attached and the results presented in Tables 2 and 3 below. 6.0 Discussion of Results Soil analyses show very low levels of TPHD in B-6,B-7 and B-8 at the 9.5 to 10 foot depth, near the occurrence of groundwater. TPHD was detected at less than one mg/Kg (<1M9/Kg) at B-5. Soil samples at B-9 at 9.5 to 10 feet and 19.5 to 20 feet near the former underground tank excavation showed TPHD was detected at less than one mg/.Kg (<1 mg[Kg). Groundwater samples showed TPHD in B-5 at 490 micrograms per liter(Ug/L) and B-7 at 300 Ug/L. B-6, B- 8 and B-9 were all 200 Ug/l or less (see Table 2). The laboratory noted that the hydrocarbons were higher boiling than typical Diesel Fuel in all samples. The site subsurface conditions Wright observed in this study are similar to those in 2003, although the WWTP has performed significant construction activity and shallow groundwater dewatering for that construction in the former UST project area. The 2003 data showed that the most elevated groundwater TPHD was at B-2 (at 33,000 Ug/l) and B-1 (810 Ug/1). B-6 drilled adjacent to the B-2 location showed 170 Ug/l and B-5 north of B-1 showed 490 Ug/l. Boring B- 7 located in the estimated down gradient position from B-2 showed 300 Ug/1. These latest groundwater samples show a significant decrease from the 2003 values. Wright had interpreted the 2003 data as a relatively small leak that appeared degraded. The data for the samples reported herein also are reported by the laboratory and not typical or higher boiling and different from a "typical" Diesel fuel and may infer fuel degradation. 7.0 Conclusions and Recommendations Wright has completed the soil and groundwater sampling and 2000-foot radius well search for the former underground diesel tank at the Wastewater Treatment Plant. The 2003 PEA study had revealed dissolved TPHD that appeared to possibly be a small leak and the dissolved data suggested that this small plume had moved north and northwest a short distance from the former underground tank. A 2000-foot radius well search. showed that there are no municipal or domestic drinking water wells within the search area. Several wells nearby the search radius are listed as either industrial or irrigation wells. The regional groundwater flow direction is estimated to be northerly. Wastewater plant and industrial waste ponds bound the site to the north, east and south. It is likely that seepage from these ponds may affect the local groundwater flow at the project site, however there was no monitoring well information available to assess local flow direction. The Page 5 of 9