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Sent' By: BASELINE; : 510 420 1:707; Sep.-S 9:12; i Page 3 ! <br /> ., BASELINE 4, �r <br /> Mr, Stuart Olsen . �> <br /> atb ,zoos s~pte <br /> ' <br /> Page 2 <br /> R; <br /> x :borings that were,installed as part of the 1998 investigation at the site,we anticipate that there ' <br /> will be two types of waste streams: 1)shallow fill; and 2)native,underlying clay soils. The <br /> fill appeals to be limited to the upper two to four feet. The analytical results from the 1998 <br /> ' j'�investigation indicate that these materials contain elevated levels of metals,specifically lead <br /> Y F .and mercury, at total concentrations greater than ten times the solubility threshold limit <br /> 1 <br /> concentration of 5 milligrams per liter(mg/L) for lead and 0.2 mglL for mercury., <br /> b. . ' y <br /> Prior to commencement of field activities, we would obtain utility clearance frorrl the <br /> F <br /> Underground Service Alert(USA). We would also prepare a site-specific health and safety <br /> plan. All field activities would be directed by a BASELINE registered geologist. <br /> .'' we would install up to eight soil borings throughout the entire site? The soil boring locations , <br /> .. <br /> would be randomly determined using a systematic approach. This involves placing the soil .. ., <br /> i <br /> borings at set intervals throughout the project:site, with an.initial randomly determined I <br /> location. Each soil boring would be drilled to a depth consistent with the proposed soil y <br /> excavation depth for;redevelopment described above,which ranges'irom two to 16 feet b ; <br /> k throughout the site <br /> At each soil borixtg location, orfs Soil sample would be. collected`from each of the two <br /> . .` <br /> anticipated waste streams(based on visual inspection of the stratigraphy encountered). For <br /> each of the two anticipated waste streams.,the soil samples collected from the.eight borings . <br /> . . _ would be composited into four composite samples,for a total of eight composite samples. <br /> �.` <br /> r eight composite samples would be analyzed for total lead and mercury, soluble.lead and <br /> mercury using the Waste Extraction Test(WET) Method.,and soluble lead and mercury using <br /> the Toxicity Characteristic Leaching Procedure (TCLP).` These analyses would determine <br /> whether the waste streams would constitute a hazardous waste.,_ <br /> 44 <br /> • iii _ -�- .:' r � ' t 4,. 4' :v - ; �4' :Z, '. !, <br /> s 'Federal and State statute9 and regulations have eritena for hazardous waste detemtiriation based on the toxicity, <br /> corrosivity,r aciivitjr,and ignitability characteristics of the waste.`Title 22 of the California Code of Regulations(CCR) <br /> specifiesthreshbldlimitconcentradonsforcertainmetals,abovewhich the wasteiscoi►sidetedaGalifomiahazardouswaste• <br /> W20"that-Contain total or soluble(using the waste Extrac#ion Test(WET]method)concentrations of specific metals in <br /> excess of the Intal Threshold Limit Cortcentradon(TTF� or the STLC are considered'a California hazardous waste y i <br /> Similarly,Federal.regulations indicate that wastes containing total or soluble{using the Toxicity Characteristic L caching <br /> 4 <br /> Procedure lTCLP]method)concentrations of sgeeific metals in excess of the Total Threshold Limit Concentration TTL.Q. t <br /> or the TCL P are considered a`Fed"hazardous waste. Based on the past investigations at the siu,this prupusa­_I assumes <br /> waste'streams would net exhibit characteristics,of corrasivity,rewtivity,or ignitabili[y. F' 3 <br /> that the a <br /> According to Sart Joaquin County,the'drilling permit obiained from the County for collection of the recent <br />! :groundwater sample maybe valid for the soil boring installation activities proposed herein,although the scope of work would <br /> first need to be reviewed, This cost estimate assumes that another:.drilling permit would not be needed,.!" <br /> 0.4 <br /> 4 1 ° ih -ij <br /> ..,+}€ '' his - .. ' ` � r •'�" a .a�rx , <br />