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r i _ Page 1 of 1 <br /> �,.r ♦J <br /> Vicki McCartney [EH] <br /> From: Vicki McCartney [EH1 <br /> Sent: Tuesday, August 19, 2008 1:03 PM <br /> To: 'Jim Barton' <br /> Subject: 222 Weber Avenue <br /> Attachments-. 222 Weber Ave.pdf <br /> Jim: <br /> I am responding to the voice message you left yesterday. You expressed concern because soil samples <br /> collected during the installation of MW-1 on July 13, 2002, demonstrate that high concentrations of soil <br /> contamination were detected after boring B-2 was advanced in February 2001 at the San Joaquin County <br /> Courthouse located at 222 East Weber Avenue, Stockton, California. <br /> Attached are Tables 1 and 2 showing historical soil and groundwater analytical results for this site, as well as <br /> three site plans that illustrate the locations of the site borings. <br /> Please compare soil data collected from MW-1 to soil data collected from B-2 found in Table 1. At 15 feet below <br /> surface grade (bsg), high concentrations of TPH-gasoline and BTEX are reported for soil samples collected from <br /> MW-1 and B-1. However, at 20 feet bsg, the concentrations for TPH-gasoline and BTEX drop significantly in soil <br /> samples collected from the two wells; and at 25 feet bsg, concentrations for TPH-g and BTEX are reported as <br /> non-detect for soil samples collected from MW-1. I believe this demonstrates vertical delineation of contaminants <br /> in soil. <br /> Also, results for soil samples collected from B-1 are reported as non-detect for contaminants of concern; and soil <br /> analytical data collected from B-3 at 20 feet bsg are comparable to soil analytical data collected from B-2 at 20 <br /> feet bsg. <br /> Please review groundwater analytical data collected from MW-1 found in Table 2. (Groundwater collected from all <br /> three monitoring wells were analyzed for 1,2-dibromoethane (EDB)and the results were reported as non-detect at <br /> 0.5 ug/L; however, these groundwater results were never reported in a table format.) <br /> I believe the groundwater results indicate that the concentrations for TPH-gasoline and BTEX have decreased <br /> significantly during the six years of groundwater sampling. Also, in January 2007, one grab groundwater sample <br /> was collected at 35 to 39.5 feet bsg from CPT-1 and only MTBE was detected at 3.1 ug/L. I believe <br /> this demonstrates vertical delineation of contaminants in groundwater. <br /> Ramage Environmental, Inc. reported in Additional Site Investigation and Groundwater Monitoring Report-Fourth <br /> Quarter 2006, dated February 16, 2007, that the estimated mass of TPH-gasoline is 294 pounds, benzene is 0.16 <br /> pounds, toluene is 6.15 pounds, ethyl benzene is 5 pounds, total xylenes is 26.23 pounds, and MTBE is <br /> 0.01 pounds. <br /> I hope this information is helpful as you decide whether this site is ready for closure. <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)468-9852 <br /> Fax: (209)468-3433 <br /> Email: v•mccartneyka?sjcehd.com <br /> 8/19/2008 <br />