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Vicki McCartney [EH] <br /> From: Jim Barton Ubarton@waterboards.ca.gov] <br /> Sent: Tuesday, May 31, 2011 1:46 PM <br /> To: Vicki McCartney[EH]: <br /> Subject: Re: Two Questions <br /> Hi Vicki; <br /> I'll have to get back to you for a definitive answer, sincemyrisk assessment source in f <br /> the office is currently gone. The following J&E link shows only soil gas and groundwater <br /> numbers for inputs.http://www.epa-gov/athens/learn2model/part-two/onsite/JnE lite.html <br /> I do know that averaging all of the soil concentrations does not show the maximum possible <br /> risk at the location of the soil sample, nor does it represent the risk from the risk <br /> drivers (benzene, etc) since the averaging of all constituents (BTEX) lowers the risk <br /> number (dilution is not the solution). . <br /> I also know that risk is additive, not an average, for each category of risk (worker, - <br /> resident adult, resident child, etc. ) . <br /> Thanks. <br /> Jim <br /> James L.L. Barton, P.G. <br /> Engineering Geologist [ <br /> California Regional Water Quality Control Board Central Valley Region, 11020 Sun Center IE <br /> Drive, Suite 200, Rancho Cordova, CA 95670 office (916) 464-4615 I <br /> fax (916) 464-4704 <br /> >>> "Vicki McCartney [EH] " <vmccartney@sjcehd.com> 5/31/2011 12 :59 PM <br /> >>> >>> <br /> Jim, <br /> I am truly sorry to bother you but Ihave two questions concerning the use of soil <br /> concentrations when running the Johnson and Ettinger Model to determine incremental risk <br /> calculations (incremental risk from vapor intrusion to indoor air, carcinogen,.. and hazard <br /> quotient from vapor intrusion to indoor air, noncarcinogen. First, can soil concentrations <br /> be used for this purpose, and if so, can the average soil concentration of benzene, <br /> toluene, ethylbenzene, and total xylenes be entered into the model? <br /> Vicki McCartney, Senior REHS <br /> San Joaquin County - <br /> Environmental Health Department <br /> 600 East Main Street <br /> Stockton, California. 95202 <br /> Phone: (209) 468-9652 <br /> Fax: (209) 468-3433 <br /> Email: vmccartney@sjcehd.com <mailto:vmccartney@sjcehd.com> l <br /> I` <br /> 1 <br />