SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

r - TABLE 1 -CHECKLIST OF REQUIRED'137(TA FOR NO FURTHER ACTION REQUESTS AT UNDERGROUND TANK SITES Site Name and Location: Carando Machine Works,420 N.Madison St.Stockton,San Joaquin County(RB#391149) Y 1 1. Distance to production wells for municipal,domestic, I A 2012 sensitive receptor survey reported no water agriculture, industry and other uses within 2000 feet of the site. Isupply wells within 2,000'of the Site. Y 2. Site maps, to scale, of area impacted showing In 4-04, two 500-gallon gasoline and one 350-gallon diesel USTs locations of any former and existing tank systems, were discovered in a sidewalk during redevelopment. Site maps and excavation contours and sample locations, boring figures showing tank locations,area of excavations,buildings and and monitoring well elevation contours, gradients, residual pollutants were provided in investigation reports. Site was a and nearby surface waters, buildings, streets, and service station in the 1950's and 1960's. subsurface utilities, Y 3. Figures depicting lithology(cross section), Site lithology consists of clay,silt,and sand to 60', the total depth treatment system diagrams,- I investigated.All figures were provided in the investigation reports. Y 4. Stockpiled soil remaining on- Approximately 860 cubic yards of excavated soil was transported to Forward Landfill in site or off-site disposal (quantity); Manteca and to Altamont Landfill in Livermore. No estimates were given for mass removed in soil over-excavation. Y 5. Monitoring wells No monitoring wells were installed at this site. remaining on-site, fate; YJ 6. Tabulated results of all Depth to groundwater varied from 12'bgs to 29'bgs. Groundwater now direction to groundwater elevations and depths to northeast. Groundwater gradient varied from 0.001 ft/ft to 0.009 ft/ft. water,- 7. Tabulated results of all sampling All data adequately tabularized in various reports. and analyses: Y❑ Detection limits for confirmation sampling 10 Lead analyses 8. Concentration contours of contaminants found and those remaining in The extent of the identified contamination is soil and groundwater, and both on-site and off-site: described in the available reports. Y❑Lateral and i Vertical extent of soil contamination Lateral and FlVertical extent of groundwater contamination 9. Zone of influence calculated and assumptions used for subsurface Soil over-excavation was the engineered remediation system and the zone of capture attained for the soil and remediation. groundwater remediation system; 10.Reports/information EY Unauthorized Release Form ❑Y QMRs(21)8-97 to 8-03 FY] Well and boring logs ❑Y PAR FRP ❑Y Other Remediation Completion Report,8/05 Re uest for Low-Threat Case Closure,6/13 Y 111.Best Available Technology(BAT)used or an explanation USTs removal,soil excavation,spreading ORC,and natural for not using BAT; I degradation. Y 12. Reasons why background wasfis unattainable Due to rise in groundwater table there is a significant smear zone of U BAT,' residual soil contamination to at least 10 feet below the water table.. N 13.Mass balance calculation of substance treated Consultants did not estimate initial mass or mass removed. versus that remaining,* 77 14. Assumptions,parameters, calculations and A soil vapor survey was not required by the regulatory agency. Soil 7 model used in risk assessments, and fate and was over-excavated to 25'bgs, which is below typical worker exposure transport modeling, depths. Site has been redeveloped as a sports complex. Consultant states site does not represent a significant risk. Site meets the Low Threat Closure Policy. 7Y 15. Rationale why conditions remaining at site will Soil and groundwater contamination reportedly are limited in extent. not adversely impact water quality, health, or other Land use(commercial)is not expected to change in the foreseeable beneficial uses,and future. By: JLB Comments:In 4-04, two 500-gallon gasoline and one 350-gallon diesel USTs were removed from the subject site.Limited residual soil contamination remains under newly built sports complex.No foreseeable changes Date: in future land use(commercial).Regional Board staff concur with San Joaquin County's Closure 6/20/2014 Recommendation.