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1117 Lone Palm Avenue, Suite 201B <br /> itCa/'[i//70 Modesto,California 953511 <br /> ATC 209-579-2221 <br /> Fax:209-579-2222 <br /> Shaping the Future <br /> SCOPE OF WORK <br /> Plannine and Permits <br /> /Cardno ATC will obtain permits for the advancement and installation of four temporary soil vapor <br /> probes. Cardno ATC will schedule field personnel and equipment, notify Underground Services Alert <br /> to locate underground utilities as required, and perform other necessary field preparation and job start- <br /> up activities. <br /> Installation of Soil Vapor Probes <br /> This task includes mobilization to the site, advancing four soil borings, and completing the borings as <br /> temporary soil vapor probes. The soil vapor probes are planned to be located between the identified <br /> source area ann-3 earby residential structures, both in the northeast corner of the site and in the eastern <br /> portion of the adjacent residential property. Estimated soil vapor probe locat' ns are shown on Figure <br /> 2, y <br /> Z�•99% <br /> The soil vapor probes will be aced to approximately'l—we feet 1. - <br /> bgs using a inch diameter rod <br /> driven by a truck-mounted direct push drill rig operated by a C57 licensed dri mg compan. . Upon <br /> completion of each boring,a temporary vapor probe asseill then be installed. <br /> Each vapor probe will be constructed using outer diameter(OD)Teflolt tubing fitted with an <br /> plastic screen tip implantlat the base of the vapor probe. e a ovegroun Teflon vapor probe tip <br /> be fitted with a swag ok valve fO purging and vapor sample collection. The screen tip and subsurface <br /> assembly will bebacgilled with four inches of 2/12 Monter- a sand and overlain with hydrated granular <br /> bentonite to seal the annular ac above the sam ling interval to prevent ambient air intrusion within <br /> Pe boring anntlltts. Each a ove' ound vapor probe aLssem y wt a secured during the two hour <br /> stabilization period. <br /> Sampling Methodology -21 IZ <br /> In an effort to appropriately conduct soil vapor sampling on site, Cardno ATC will follow theuig delines <br /> established by the Los Angeles Regional Water Quality Control Board (LA RWQCB) and the <br /> De ailment of Toxic Substances Control DTSC) in documents entitled Advisory.– Active–Sail-Gas. <br /> �Y Investigations, dated April 2012, and Final–Guidance or t e va uationmitigation of Subsurface <br /> Vapor Intrusion to Indoor Air, dated October 2011. \� �� <br /> o , <br /> _ Soil Vapor Sample Collection J 0 C" <br /> r� FAfter each soil vapor probe assembly is complete, a minimum of 2 hours stabilization time will be <br /> r allowed before collecting each vapor sample. Once the vapor points have b en allowed to stabilize,the <br /> N above ground sample equipment will be assembled and tested for lea s. ree a volumes, using a <br /> 60-millimeter(ml) syringe, will be removed from the vapor pro e assembly. The purge volume will be <br /> volume of the above round assembly. hmgart I p p t and he tubing <br /> calculated based on the internal volume of to d annular space around the robe t <br /> �V g ( ISQIc-I� <br /> :m8mmpornuamar.2015 WS WP.tloc <br /> 4 Cardno ATC <br /> �,, LV <br />