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Cintra Group Property,Tracy,CA Site Code 9294 Letter to SJCPHS/EHD Page 2 f22 ppb)have impacted shallow groundwater beneath the site; however all levels detected are far below the respective State Primary Maximum Contaminant Levels (MCLs), and below the Secondary MCLS, with the exception of xylenes (taste and odor for drinking water objectives is 20 ppb). The concentrations detected will not affect the limited beneficial uses of groundwater beneath the site. GROUNDWATER QUALITY The inferior quality of the upper zone is a result of the supply of groundwater from the Coast Range which contains high levels of chlorides, sulfate, and boron; and, water from the western edge of the San Joaquin River which contains water similiar to the Delta groundwater. (Department of Water Resources, Bulletin 146, San Joaquin County Groundwater Investigation, July 1967) The City of Tracy Clerk's Office personnel indicated that the installation of domestic wells within the City limits is prohibited (personal communication, March 1993). Deep aquifers which lie beneath the Corcoran Clay layer in the Tracy area generally produce good water quality for domestic and agricultural purposes. However, in the past, it was common practice to gravel pack agricultural wells and perforate all producings zones from the surface down past the Corcoran Clay layer. Water quality problems in the lower zones have resulted from these multiple aquifer wells due to communication with upper zones that contain inferior quality water. DISCUSSION Since there has been no history of contamination or potential sources of contamination on this site, it is RESNA's opinion that this site has been properly characterized. The low levels of petroleum hydrocarbons encountered in the groundwater beneath the site are no threat to public health or to beneficial uses. It is RESNA's understanding from recent conversations with the RWQCB that staff time will not be allotted for reviewing cases of this nature. This property is slated for residential development. Unfortunately, local agencies are apprehensive to allow development to proceed until the RWQCB reviews and concurs that no further action is necessary at this time (i.e., the City of Tracy Planning Commission has denied the issuance of building permits, in similiar instances, pending written concurrence from the RWQCB). The priorities of the RWQCB are appropriately focused on sites which pose a significant threat to water quality. The minor levels of volatile organics found in the groundwater at this site should not interrupt business operations. This impasse will result in undue economic hardship for Cintra Group L.P.. srorto�.�vi.