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r� Mr Martin Harms Page 2 of 3 low risk, groundwater contamination case EHD refected Ground Zero's recommendation in a letter dated August 1, 2002 and requested additional mvestigaton into the vertical and lateral extent of groundwater contamination at the site Ground Zero responded to EHD's request in a letter dated September 27, 2002, wherein Ground Zero addressed several concerns presented in EHD's letter and recommended again that the site be closed Site Activities Activities at the site included monitoring all site wells, purging and sampling groundwater from all site wells, analyzing samples for total petroleum hydrocarbons as gasoline (TPHg), benzene, toluene, ethylbenzene, total xylenes (BTEX), oxygenated gasoline additives, 1,2-dichloro ethane (1,2-DCA), and ethylene dibromide(EDB) Groundwater Monitoring and Sampling Monitoring wells MW I through MW4 were monitored and sampled on March 7, 2003 Groundwater elevations were calculated by subtracting the measured depth to groundwater in each well from the respective wellhead elevation The depth to groundwater in the wells ranged from 5 95 to 6 82 feet below the tops of the well casings (btoc) The potentiometric surface fell an average of 1 07 feet since last measured on March 22, 2002 Groundwater flowed in a west-northwesterly direction with a gradient of approximately 0 001 ft/ft A potentiometric surface map generated from the March 7, 2003 monitoring data is shown on Figure 2 Groundwater monitoring data are summarized in Table 1 Monitoring data sheets are included in Attachment A Prior to sampling, monitoring wells MMI through MW4 were purged of at least three well casing volumes The physical parameters of temperature, pH and electrical conductivity were measured during the purging process Groundwater samples were collected after the physical parameters stabilized and groundwater in the wells recovered to at least 80% of pre-purged levels The samples were placed into an ice chest refrigerated to approximately 4°C and transported to Argon Laboratories (FLAP #2359) under chain of custody protocol Well purge logs are included in Attachment A Groundwater Analytical Results Groundwater samples were analyzed for the presence of TPHg, BTEX, and oxygenated gasoline additives (including the lead scavengers 1,2-DCA and EDB) using EPA methods 8015K 8021B, and 8260B, respectively TPHg was detected in wells MW 1 and MW2 at concentrations of 260 parts per billion (ppb) and 140 ppb, respectively No TPHg was detected in well MW3 or well MW4 Benzene, ethylbenzene, and xylenes were detected in well MW 1 at concentrations of 2 6 ppb, 5 8 ppb and 13 ppb, respectively No BTEX constituents were detected in wells MW2, MW3, or MW4 G 1GROUNDZFkTut Boy\ReportslQMRV QM2003 doc