Laserfiche WebLink
Working To Restore Nature <br /> Groundwater samples were collected from the wells in May, June and August 1991 Low levels <br /> of petroleum hydrocarbon constituents were detected in wells MW I and MW2 dunng the May <br /> ' sampling event, only TPHd was detected in well MW2 in June, low levels of benzene were <br /> reported in the samples from MW 1 and MW2 during the May and August, 1991 sampling <br /> ' events All detected analytes were present at levels below respective Stated Maximum <br /> Contaminant Levels (MCLs) <br /> Subsequent groundwater samples collected from site monitoring wells indicate that groundwater <br /> rbeneath the site has not been significantly impacted by dissolved petroleum hydrocarbons TPH <br /> concentrations have ranged from non-detect to 160 ppb and BTEX constituents have remained <br /> ' at or below detection limits Historical results of groundwater samples are summanzW on Table <br /> 3 <br /> The most recent monitoring and sampling activities were conducted by RESNA on August 23, <br /> 1993 Water level measurements were collected from each monitoring well using a Solinst <br /> Water Level Meter (Model 101) Groundwater was detected between approximately 62 and 64 <br /> feet below the tops of the well casings Groundwater monitoring data show that groundwater <br /> has risen an average of 0 38 feet since last monitoring on April 1, 1993 Table 2 summarizes <br /> groundwater elevation data A groundwater gradient map was created using the August 23, 1993 <br /> i <br /> ' data The gradient was approximately 0 025 feet/foot or 132 feet/mile in a northwesterly <br /> direction (Figure 3) This groundwater gradient is consistent with previous monitoring rounds <br /> Field monitoring data are presented in Appendix I <br /> ' At Chevron's request, groundwater samples were collected from wells MW 1, MW21 and MW3 <br /> Prior to sampling, more than five well volumes of water were purged from each well All <br /> ' purged water was pumped into an onsite baker tank for future disposal Groundwater samples <br /> were collected from the wells after stabilization of pH, electrical conductivity' (EC) and <br /> temperature Field purge logs are included in Appendix I The samples were collected using <br /> N (Prot DisklRepoctslsAR1093 FNL) 3 <br /> i <br /> I <br />