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s <br /> ' Diamond Manteca,CA-November 1993 Groundwater Momtonng Page 7 <br /> Volatile hydrocarbons decreased significantly in wells MW2 and MW3 to 60 and 10 ppb respectively, from <br /> 310 and 290 ppb recorded during the June 1993 sampling event Total hydrocarbon levels rose slightly in <br /> 1 MWI to 30 ppb from X20 ppb recorded during the June 1993 monitoring event <br /> Lead levels ranged from 15 to 17 ppb, and illustrate a continuation of the contaminant trend to date <br /> 5 2 Monitonng Wells BEI-MW4, BEI-MW5 and BEI-MW6 <br /> As previously recognized, significantly elevated levels of BTEX and volatile hydrocarbons exist at all three <br /> of the BEI series monitoring wells A general decrease in BTEX and volatile hydrocarbons was observed <br /> in MW4 and MW5, while a net increase is evident in MW6 Lead levels increased significantly in all three <br /> BEI series monitoring wells Lead levels ranged from 58 to 320 ppb <br /> 6.0 REGULATORY SITE VISITS <br /> Ms Margaret Lagorio, Senior REHS with the San Joaquin County PHS/EHD was notified on November <br /> 29, 1993, that sampling activities were scheduled for the Diamond Lumber - Manteca, California site to <br /> begin at 8 00 a m on November 30, 1993 <br /> On November 30s 1993 sampling activities were completed ahead of schedule, prior to Ms La orio's <br /> r arrival Immediately after sampling activities were completed, SRK contacted Ms Lagorio via telephone <br /> at the PHS/EHD office in Stockton, California The SRK field representative explained that sampling <br /> activities had been performed following PHS/EHD recommended procedures as detailed in Sections 4 1 and <br /> 4 2 of this quarterly monitoring report <br /> Ms Lagorio did not make any recommendations or commentary during this telephone conversation <br /> regarding sampling activities performed in her absence <br /> 7.0 SUMMARY OF FINDINGS <br /> ' Over the period of monitoring at this property (initiated in 1989 by BEI and performed regularly by SRK <br /> since October/November 1991), groundwater elevations have varied due to abnormal drought conditions <br /> ' followed by near normal seasonal precipitation conditions The variance in water table elevations has likely <br /> affected local groundwater flow conditions as well as fluctuations in contaminant levels <br /> 4) <br /> 1 12"42MQMyM- Steffen Robertson and Kirsten <br />