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the deadline and was granted until December 1991 to submit its work plan (14). The RWQCB <br /> inspected other possible sources for the contamination near the Busy Bee site and concluded that <br /> they were not likely sources of PCE contamination (15). Since an area of PCE was detected <br /> migrating from the location of another dry cleaners site (Guild Cleaners) to Well 3, the RWQCB <br /> concluded that Busy Bee was not the source of PCE contamination detected in Well 3 (13). <br /> 3.2 EPA Sampling <br /> No sampling by the EPA has been conducted at, or proposed for, the Busy Bee site because <br /> existing sampling data provide sufficient information to evaluate the site at this time. <br /> 4.0 HAZARD RANKING SYSTEM FACTORS <br /> 4.1 Sources of Contamination <br /> PCE-contaminated condensate and cooling water, produced in the dry cleaning process, are likely <br /> to previously have been discharged into the sewer line. PCE concentrations of 12 ppb and <br /> 0.66 ppb, respectively, were detected in samples of condensation water and cooling water taken <br /> from the facility. (6) Waste barrels containing sludge and condensate stored on site are also a <br /> potential source of contamination (10). <br /> 4.2 Groundwater Pathway <br /> 4.2.1 Hydrogeological Setting. The City of Lodi lies in the Great Valley geologic province in <br /> northern San Joaquin County. Heterogenous mixtures of clay, silt, sand, gravel, and some beds of <br /> claystone, siltstone, and conglomerate underlie the area to a depth of about 2,000 feet bgs. <br /> Continental and marine rocks and deposits underlie the area below a depth of 2,000 feet. (8) <br /> The Miocene Valley Springs Formation overlies the deeper continental and marine deposits. The <br /> Valley Springs Formation is composed of sandstones, mudstones, ash, and tuffaceous beds. Its <br /> source is volcanic-rhyolitic. The Mehrten Formation overlies the Valley Springs Formation. The <br /> Mehrten Formation is characterized by abundant black volcanic sandstones and conglomerates <br /> with interbedded dark colored mudstones and volcanic mud flow deposits. The Pliocene Laguna <br /> Formation overlies the Mehrten and is composed of weakly consolidated sands, gravels, and silt <br /> and clay beds. The Turlock Lake Formation of early Quaternary (Pleistocene) age overlies the <br /> Laguna Formation. The Turlock Lake Formation is similar in composition to the Laguna <br /> Formation. A complex sequence of weakly consolidated to unconsolidated alluvial deposits of <br /> Pleistocene to recent age overlies the Turlock Lake Formation. (8) <br /> The younger sedimentary units of alluvial deposits, the Turlock Lake Formation, and the Laguna <br /> Formation are the most widely used formations for sources of groundwater. In the Lodi area, the <br /> Turlock Lake and Laguna formations are the most likely water-producing zones. (8) <br /> Static water levels in Well 4, located 0.1 mile north of the Busy Bee site, were 49.9 feet in 1989 <br /> and 53.6 feet in 1990 (8). The depth to groundwater at Well 3, located 0.3 mile southwest of the <br /> site, is approximately 50 feet bgs (21). Three soil borings advanced as part of the site-specific <br /> investigations conducted at the Busy Bee facility also indicate a static groundwater depth of <br /> SI Busy Bee Laundry and Cleaning-0 (F) • 1/93 8 Printed on 50% recycled paper. Za�� <br />