SITE INFORMATION AND CORRESPONDENCE

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•� F TABLE 1 -CHECKLIST OF REQUIRED DA"r FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES Site Name and Location: Nulaid Foods, 337 Fourth Street, Ripon, San Joaquin County N 1. Distance to production wells for municipal,domestic, agriculture, industry A well survey was not conducted. and other uses within 2000 feet of the site; 2. Site maps, to scale, of area impacted showing locations of former and existing tank systems, In November 1998, two 10,000- excavation co.Ontours and sample locations, boring and monitoring well elevation contours, gallon diesellgasoline tanks gradients, and nearby surface waters,buildings, streets,and subsurface utilities; were removed from the site. Y� 3. Figures depicting lithology(cross section), treatment system diagrams; No treatment system was used. FTI 4. Stockpiled soil remaining on-site or off-site disposal(quantity); Approximately 150 cubic yards of soil was excavated from the tank pit The disposition of the soil is unknown. NA5. Monitoring wells remaining on-site, fate; No monitoring wells were installed. 6. Tabulated results of all groundwater elevations and depths to water,' Between 1978 and 1999,groundwater elevation varied, from 20 and 30 feet bgs. Documented groundwater Now direction is north/northwest Y In November 1998, TPHd and xylene were detected in soil at 66 mg/kg and 7.Tabulated results Of all sampling and analyses: 9.2 mg/kg,respectively. In 1999,results of two soil borings revealed 10 mg/kg Detection limits for confirmation sampling TPHd in soil. Groundwater samples showed TPHd at 0.00017 mg/l,benzene at Lead analyses 0.0004 mg/1,and toluene at 0.006 mg/I. MtBE was not detected in any samples from the site. 8. Concentration contours of contaminants found and those remaining in soil and groundwater, and both on-site and off-site: Y❑ Lateral and 71 Vertical extent of soil contamination 0 Lateral and rvi Vertical extent of groundwater contamination NA 9.Zone of influence calculated and assumptions used for subsurface No subsurface remediation system was used at remediation system and the zone of capture attained for the soil and this site. groundwater remediation system; Q10.Reports/information Y❑ Unauthorized Release Form NA 1.MRs(Dates) Welland boring logs EIPAR FAI FRP 19 Other(report name)4 October 1999 Closure Summary Y� 11.Best Available Technology(BAT)used or an explanation for not using BAT,' The leak sources(tanks)were removed from the site. Y 12.Reasons why background wasrs unattainable using BAT, Remaining contaminants require time to naturally attenuate. N� 13.Mass balance calculation of substance treated versus that remaining; F] 14.Assumptions,parameters, calculations and model used in risk assessments, and fate and transport modeling; M15.Rationale why conditions remaining at site will not adversely impact water quality, health, or other beneficial uses;and 0 16.WET or TCLP results By:1,4� Comments: Elevated levels of TPHd and xylene were detected in soil during the tanks'removal. Approximately 140 cubic yards of (J soil was removed from the tank excavations. Groundwater was not encountered during the excavation activities. In August 1999, Date: two investigative soil borings were advanced to 30 feet bgs. Resulting soil and groundwater samples showed minimal contamination from the former tank release. No MtBE was detected in samples from the site. Based on the absence of MtBE in the soil and groundwater samples and the likely degradation of the remaining residual hydrocarbons, staff concurs with San Joaquin [ County closure recommendation.