SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

JUN/14/2005/WED 01:50 PM COS IISG & REDEV Ms. Kitty Walker FAX N. 20993750qq P. 003 2 7 June 2006 constituents. An investigation revealed that the railroad corridor was under laid with ballast, as expected, but also a drainpipe was discovered to run the length of the railroad corridor. The drainpipe was constructed of a 12-in diameter corrugated perforated pipe and was buried at about 4.5 feet below ground surface. As reported and is shown in Attachment 3, the widest dimension of the excavation that resulted from the removal of the drainpipe and polluted soil was about 20 feet. Also, reported was that at various locations sheen was observed on the surface of groundwater encountered at about 18 feet below ground surface. The highest concentration of total petroleum hydrocarbons found in the excavation groundwater was in the diesel range at 4,600 pg/I. The 28 March 2006, Report of Findings of Soil Excavation and Subsurface Soil and' Groundwater Investigation Stockton WorkNet cites the cleanup activities at the RDA Waterfront Project Area 2A as a possible source for the soil and groundwater pollution found beneath Project Area 3. The RDA Waterfront Project Area 2A is.divided.into three areas. The responsible party is actively cleaning up the area adjacent to the apartment complex and on-. site pipelines and other preferential pathways have been investigated and work plans are approved for their removal. However, the RDA has responsibility for the investigation and cleanup of two of the areas at Project Area 2A that it obtained under eminent domain condemnation in 1981. Since the conclusion of the eminent domain condemnation process in about 1983, the RDA has not conducted any investigation or cleanup of these two nearby. areas. Therefore, there is no data to support the speculated source of the pollution. As direct cause and effect, it is clear that the hydrocarbon soil and groundwater pollution present beneath Project Area 3 was due to leaching from the pollution present within the drainpipe,.which is a preferential pathway for any, pollution encountered along its entire length. Attachment 4 is an aerial photograph that shows the length of the railroad spur. It appears from the photo that the rail spur ended on Project Area 24 and tied into the main railroad track south of Mormon Slough and west of S. Commerce Street. It is not known where the drainpipe runs. Pollution may be present along the remaining length Of the railroad right-of- way and the drainpipe, not just the portion that transects Project Areas 3, 4 and 24. The RDA must investigate and cleanup the pollution beneath the entire railroad corridor associated with its property. In addition, until the RDA conducts the investigation of the .Morton-Alco and the, UNOCAL sites and determines if pollution migrated off-site from these areas, and until the entire length of the railroad spur and drainpipe is investigated, the origin of the release cannot be determined and it cannot determine who is responsible for that pollution release. Project Area 24 contains two groundwater monitoring wells (MW-3 and. MW-7) that are associated with RDA Waterfront Project Area 2A. During the February 2006 sampling event, groundwater in MW-3 and 7 showed non-detect for most constituents of concern_ However, total petroleum hydrocarbons in the diesel range were present in groundwater from both wells at 220 and 110 pgil, respectively, and arsenic was present at MW-3 at 110 ug/I. No investigation work has been conducted at Project Area 4. Attachment 5 contains photographs taken in April 2006, which show the present condition of the railroad corridor for • Project Areas 3, 4 and 24.