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1 ' evident from the investigations performed at the site between 1994 and 1999, TPH-g and BTEX concentrations in soil were either significantly low and/or non-detect, except for soil samples collected in boreholes MW-2 in 1994 and MW5 in 1999. Monitoring well MW-2 was installed northeast of the former UST. Contaminated soils in the vicinity MW-2 and the former UST were removed during remedial excavation activities in ' December 1994. Approximately 108 cubic yards of soil was excavated from the source area and transported for disposal to an appropriate facility. ' In addition, soil samples collected from eleven soil probes advanced in the vicinity of former UST in November 1995 and January 1996 did not contain significant concentrations of TPH-g or BTEX. ' 6.2 Groundwater ' Based on results from quarterly groundwater monitoring events conducted at the site from 1994 to present (approximately eight years), it appears that the petroleum impact to groundwater was limited and well defined. Impact to groundwater was mainly limited to monitoring wells MW-2 and MW-5. Groundwater collected from these wells at the last ' quarterly monitoring event were found to be non detect for all analyzed components including TPH-g and BTEX. Over the past eight years of monitoring, TPH-g and benzene concentrations have steadily and consistently decreased in MW-2 and MW-5 to the current level of non detect. The most- significant decline in TPH-g and benzene concentrations in these wells occurred between the ' December 2000, November 2001, and May 2002 sampling events. In MW-2 during that time TPH-g decreased from 1,100 ppb to 134 ppb to non detect (ND) and benzene decreased from 33 ppb to 4.1 ppb to ND. In MW-5, TPH-g decreased from 55 ppb in to ND and benzene ' decreased from 3.8 ppb to 0.62 ppb to ND. This steady and consistent decline in TPH-g and benzene concentrations can be partially attributed to the natural biodegradation of petroleum hydrocarbons by indigenous petroleum-consuming bacteria at the site. This is evidenced by ' the decrease of dissolved oxygen (DO) concentrations and increased oxidation reduction potential (DRP) observed in groundwater during the quarterly monitoring events. ' Toluene, ethylbenzene, and total xylene concentrations at the site have consistently remained near or below their respective MCLS for several years. The downward trend in contaminant levels has now reached ND as would be expected given, in part, the time frame of well over a ' decade since the contaminate source, the UST, was removed. Based on this information JJW believes that the site be considered for closure. ' 7.0 REQUEST FOR SITE CLOSURE JJW believes that the site requires no further action and requests that site closure be __.___considered based on the.following: • Laboratory analyses of groundwater from the five monitor wells have shown a consistent ' down-ward trend to the current analytical result of non detect for all analyzed components from the most resent monitor well sampling event. ' • Justification and rationale presented in the previous section. ' 6 JJW GEOSCIENCES Inc.