SITE INFORMATION AND CORRESPONDENCE

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The RWQCB sampled the sewer line around the Busy Bee site in September 1989. The RWQCB collected two sewer samples from the first manhole downstream of Busy Bee's sewer lateral in September 1989. A liquid sewer sample collected under ambient conditions indicated concentration levels of 54 ppb of TCE and 700 ppb of PCE. A flushed sewer liquid sample indicated concentration levels of 8,200 ppb of TCE and 280,000 ppb of PCE. (7) 3.1.3 Soil Sampling. Site-specific investigations were conducted in February 1991 by L&S and a report was submitted in May 1991. Initially,cone penetration testing was attempted on site as an investigative method. High-tip resistance and sleeve friction resulted in refusal at depths of 23 to 24 feet at two locations, and ended the on site use of this investigative technique. The work plan was revised, and L&S proposed to the RWQCB that a hollow-stem auger rig be used instead of the cone penetrometer rig. Three soil borings were advanced to a maximum depth of 58 feet using a hollow-stem auger. Soil samples were collected at five-foot-depth intervals using a split-barrel sampler. The soil samples were used for lithological evaluation and chemical analyses of volatile halogenated hydrocarbons using EPA Methods 8010 and 8020. A total of 22 soil samples were collected from the three soil borings. No PCE was detected in any of the soil samples from two of the borings. PCE was detected in five of the 11 samples submitted for analysis from the third boring. PCE concentrations of 93 ppb and 290 ppb were detected in the soil samples collected at depths of 7 feet and 45 feet,respectively,from the third boring. (8) 3.1.4 Soil Gas Sampling. The RWQCB conducted soil gas surveys in the City of Lodi in September and December 1989. The soil gas survey conducted in September 1989 consisted of placing 45 PETREX tubes containing carbon-coated wire, open end down, 10 to 12 inches below ground surface (bgs). The tubes were removed after approximately six weeks and sent to a laboratory for VOC analyses. Based on the soil gas survey results, three areas of PCE contamination were detected in the City of Lodi. PCE contamination was detected near the sewer line that served Busy Bee. Background soil gas ion count values for PCE ranged from 3,000 to 9,000. Soil gas samples collected downgradient of the facility indicated PCE ion counts of 240,000. (7) The soil gas survey conducted in December 1989 consisted of placing 20 PETREX soil gas tubes in the soil at the locations of previously operating dry cleaners to determine whether these facilities may also have contributed to the PCE contamination found in Well 3. In addition, some tubes were placed in the soil surrounding the Busy Bee site to determine the presence of PCE to the north, south, east, and west of the site. Only one soil gas tube was placed close to the Busy Bee site. PCE ion counts of 239,000 were detected in the sample. (13) The RWQCB conducted a third soil gas survey in January and February 1991. The purpose of the third soil gas survey was to further define the extent of PCE contamination. As part of the third soil gas survey, 17 PETREX soil gas tubes were placed in the soil on January 14, 1991 and removed on February 25, 1991. Of the 17 soil gas tubes, three soil gas tubes were placed 0.1 mile downgradient of the Busy Bee site and near other commercial establishments. None of the tubes showed PCE levels in the soil gas above background. (20) Upon reviewing the results of the soil gas surveys and the sewer sampling conducted by L&S and the site-specific investigations, the RWQCB concluded that there is soil and groundwater contamination near the Busy Bee site. However, the extent and source of soil and groundwater contamination was not conclusively determined by these investigations. Hence, Busy Bee was required to submit a work plan for an additional site investigation, including the installation of at least three groundwater monitoring wells by July 1991. (4) Busy Bee requested an extension of SI Busy Bee Laundry and Cleaning-0(F)• 1/93 7 Printed on 50%recycled paper. ��