|
i ABLE 1 -CHECKLIST OF REQUIRED DATA
<br /> FOR NO FURTHER ACTION REQUESTS AT UNDERd ROUND TANK SITES
<br /> Site Name and Location: Ripon Farm Service, 932 S.Hwy 99 E.Frontage!2'd.,Ripon, San Joaquin County(RB#390821)
<br /> _yj 1. Distance to production wells for municipal, domestic, A 1998 sensitive receptor survey identified one municipal
<br /> agriculture, industry and other uses within 2000 feet of the site. water supply well(750'west)and twelve domestic or
<br /> irrigation wells;within the 2,000'search area;the nearest
<br /> wells are 75'to lithe north(Jimco Truck Stop), and 250'to
<br /> the southeast(Ripon Farm Service). None of the wells are
<br /> threatened by the release.
<br /> _yj 2. Site maps, to scale, of area impacted showing locations of In June 1987,,one 10,000-gallon gasoline, two
<br /> any former and existing tank systems, excavation contours and 10,000-01
<br /> 1
<br /> lon diesel, and one 7,500-gallon diesel USTs
<br /> sample locations, boring and monitoring well elevation and associatedi piping were removed.
<br /> contours, gradients, and nearby surface waters, buildings,
<br /> streets, and subsurface utilities; M
<br /> Y 3. Figures depicting lithology(cross section), treatment system Site lithology consists of clay,silt,and sand to 50', the
<br /> total depth investigated.
<br /> diagrams, „ ,,
<br /> N 4. Stockpiled soil remaining on-site or off-site disposal(quantity); The fate of the excavated soil is not discussed in the
<br /> availabie re oris.
<br /> f y 5. Monitoring wells remaining on-site, fate; Six monitoring wells(MW--1 through MW-5,MW-9, and MW-10)and nineteen
<br /> remediation wells(VW-1A&B through VW--3A&B, VW-4 through VW-8,
<br /> VW-9A&B, VW-10 VW-11;and IAS='1 and iAS-4)will be property destroyed.
<br /> - — — ---Depth=to-groundwater-varied-from-14'-to-26-'-bgs.-Groundwater=flow _-— —
<br /> 6. Tabulated results'of all groundwater.
<br /> elevations and depths to water, direction varied from west to northwest, and groundwater gradient
<br /> varied from 0.0025 to 0.05 ft/ft..jl.
<br /> 7. Tabulated results of all sampling All data adequately tabularized in"various reports, including closure report.
<br /> and analyses: ;
<br /> 0 Detection limits for confirmation
<br /> sampling
<br /> ❑Y Lead analyses
<br /> Lyj 8. Concentration contours of contaminants found and those remaining in soil and :' The extent of the identified
<br /> groundwater, and both on-site and off-site: contamination shown in applicable
<br /> reports.
<br /> El Lateral and A Vertical extent of soil contamination
<br /> Lateral and F1 Vertical extent of groundwater contamination:r
<br /> i 9. ,lone of influence calculated and assumptions used for subsurface remediation Soil vapor extraction and air sparging
<br /> system and the zone of capture attained for the soil and groundwater remediation were the active remediation.
<br /> system" M i
<br /> 10.Reports/information ❑Y Unauthorized Release Form ❑Y QMRs 57 from 5/94 to 5/09
<br /> PAR �y FRP �y Other Closure Report(11109), Soil Gas Report(4110),
<br /> �y Welland boring logs .10
<br /> Soil Vapor Intrusion Report 5111 M p
<br /> TF 11.Best Available Technology(BAT) used or an explanation for not USTs removal,soil vapor extraction,air sparging,
<br /> using BAT, and naturallat#enuation.
<br /> E .1.2. Reasons_why backgr;oun.d_wasCs ___Minima!_r_esidsral soil confarrtination remains_on_site. -
<br /> ttainable using BAT; ~
<br /> i' The consultant estimated TPH mass removed as 275 lbs in soil,and
<br />[; y 13.Mass balance calculation of substance treated residual TPH mass in soil as 317 lbs
<br /> versus that remaining; i}
<br /> 7Y 14. Assumptions, parameters, calculations and The initial TPHg soil gas results(3/09)failed the Region 2 commercial
<br /> model used in risk assessments, and fate and ESLs.A second soil gas survey(4111)at the same initial locations and
<br /> transport modeling; post remediation soil samples(10103)passed the ESLs and CHHSLs.
<br /> Water qua@ty goals have been reached.
<br /> y 15. Rationale why conditions remaining at site Soil contamination reportedly,is limited in extent and no longer
<br /> will not adversely impact water quality, health, or leaching to groundwater faster than natural attenuation. Land use
<br /> other beneficial uses;and (commercial)is not expected to change in the foreseeable future. Vapor
<br /> intrusion risk has been,
<br /> addressed.
<br /> By: JLB Comments:In June 1987, one 10,000-gallon gasoline, two 10,000-g4llon diesel, and one 7,500 gallon diesel
<br /> L� 1 USTs and associated piping were removed from the subject,Site. Based upon 57 quarters of groundwater
<br /> Date: monitoring showing a stable plume reaching water quality goals, the limited extent of contamination
<br /> 10/25/2011 remaining in soil,no foreseeable changes in land use,and limited Threats from soil and soil vapor intrusion,
<br /> IL
<br /> Realonal Board staff concur with San Joaauin County's Clo�ure Recommendation.s
<br />
|