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i ` I FOURTH QUARTER,2001 GROUNDWATER MONITORING REPORT • JAMAR OIL DISTRIBUTION MAY 2002 Summary of Previous Investigations In 1995, a 300 gallon waste oil UST and a 500 gallon kerosene UST were excavated and removed from the site No environmental issues were documented with the removal of these tanks In December 1998 two 6,000 gallon and one 10,000 gallon gasoline USTs were excavated and removed from the site and replaced with a two compartment 20,000 gallon UST meeting EPA and State of California upgrade requirements Soil samples taken in conjunction with the tank removal contained detectable concentrations of petroleum hydrocarbons and on January 27, i 1999, an Unauthorized Release form was filed with the County An additional Unauthorized Release was filed with the Country on June 11, 1999 In response to a directive from the County, John P Cummings&Associates (JPCA) conducted a subsurface investigation on September 8-9, 1999,by installing and sampling three monitoring wells (MW-1,MW-2,and MW-3) MW-1, MW-2, and MW-3 were drilled to approximately 78 feet bgs, 74 feet bgs, and 74 feet bgs, respectively and sampled every 5 feet Groundwater samples were collected from the three wells on September 23, 1999 On August 21,2000, JPCA did a further subsurface investigation by drilling and sampling one soil boring(B1) and installing and sampling two additional monitoring wells(MW4 and MW-5) The soil boring was drilled to approximately 115 feet bgs and sampled every 5 feet MW-4 and MW-5 were drilled to approximately 75 feet bgs with soil samples collected every 5 feet Groundwater samples were collected from MW-1,MW-2,MW-3,MW4 and MW-5 on August 30,2000 The results of this investigation are documented in JPCA's 2"d Phase 11 Environmental Assessment Report dated October 25, 2000 As a result of this investigation,the County requested a workplan for further site investigation s GHH assumed environmental consulting responsibilities for the site in July 2001 and has performed quarterly groundwater monitoring and reporting since that time In March 2002, GHH submitted an Additional Assessment Workplan to conduct further investigation at the site in compliance with the County's directive SCOPE OF WORK Groundwater monitoring and sampling activities were conducted at the site on December 10, 2001 The following is a brief summary of the scope of work authorized by JAMAR Measure depths to groundwater in monitoring wells MW-1 through MW-5 Purge a minimum of three equivalent well volumes of groundwater from each of the wells and momtor for pH, temperature and conductivity 2