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Manteca Quarterly Groundwater Monitoring Page 5 ' TABLE 2• Analytical Groundwater Data November 1991 and April 1992 November 24 1 1 Arlt i3 1��1 SRX SRIF SRXIl R1 Sim Ml"-MANt MAN MW3-MAN l WI-MAN MMI N 1 W3 Al [:Vo;latLle Hydrocarbons ND ND ND ND 1,800 ppb ND Benzene ND 16 ppb ND ND 220 b ND Toluene ND ND ND ND ND ND Ethyl Benzene ND ND ND ND ND ND Xylenes ND 0 90 ppb ND ND 120 ND Lead 18 b 350 b 24 b 26 PPb 57 PPb 1 27 ppb NOTES ND = Analytes reported as ND were not present above Detection Limits Detection Limits Volatile Hydrocarbons 50 ppb Benzene 0 50 ppb Toluene 0 50 ppb Ethyl Benzene 0 50 ppb Xylenes 0 50 ppb Lead 0 50 ppb April 1992 sampling events are provided in Appendix A, and copies of the Geologic Logs and Monitoring Well Construction Diagrams are provided in Appendix B The static water levels in each of the three monitoring wells rose significantly since November 1991, likely due to seasonal variation The exact amount of precipitation or infiltration is unknown, however, the elevated levels of volatile hydrocarbons, benzene and xylenes may be the result of seasonal fluctuations in the static water table 6.0 REGULATORY SITE VISITS No representative of any regulatory agency was present during groundwater sampling activities Ms Margaret Lagorio, Senior REHS with San Joaquin County REHS/EHD, was informed of the field schedule 7.0 SUMMARY OF FINDINGS The constituents of BTEX or Volatile Hydrocarbons were not detected in groundwater samples collected from monitoring wells MW 1 or MW3 Volatile Hydrocarbons were detected in monitoring well MW2 at 1,800 ppb, as well as Benzene (220 ppb), and Xylenes (120 ppb) Lead was detected in all three monitoring wells lead concentrations included 26 ppb in monitoring wells MWI, 57 ppb in MW2, and 27 ppb in MW3 32504 2211)r[rly(il 22 Steffen Robertson and Kirsten