ARCHIVED REPORTS_XR0007255 - Laserfiche WebLink

Home Browse Search

Mr Mike Infurna Page 3 • Department (EHD) staff expressed concern that the inactive wellbore could function as a conduit for contaminant migration and directed that the well be properly destroyed The inactive water supply well was destroyed by perforating the casing with explosives and grouting with cement Prior to abandonment, the total depth of the well was measured by running a downhole video camera into the well to visibly ensure no obstructions were present The well was found to be 136 feet deep with perforations from 116-125 feet In order to perforate the well casing, detonating cord (with booster charges placed at 10-foot intervals) was placed in the well from total depth to 15 feet below grade Cement was then pumped into the well in one continuous operation until the well was full The water displaced by the cement was contained in the excavation surrounding the well, which was lined with plastic sheeting, and pumped into a DOT approved 55-gallon drum The dozer blade of a backhoe was placed over the well in order to contain the cement effected from the well when the charges were detonated After the charges were detonated, the well pad and upper well casing were removed using a backhoe More cement was added to the borehole until completely full The cement was allowed to spill and form a mushroom cap below ground surface Native soil was used to complete the excavation to grade Attachment B contains a copy of the well destruction permit issued by EHD, a copy of the Inspection Report Issued by EHD, and a copy of the well log created by Water Well Technologies using downhole video equipment GROUNDWATER ANALYTICAL RESULTS TPHg and BTEX compounds were not detected in the samples from wells MW5, MW7 and MW1D Benzene was not detected in well MW3 TPHg was detected in the samples collected from the remaining site wells at concentrations ranging from 470 parts per billion (ppb) in MW6 to 140,000 ppb in MW 1 Benzene levels in these wells ranged from 3 9 ppb in UH7 to 17,000 ppb in well MW 1 Analytical results are summarized in Table 2 Attachment C contains laboratory reports and chain of custody documentation EDB was not detected in any well The gasoline additive 1,2-DCA was not detected in wells MW3 and MW7 1,2-DCA was present in each of the other wells at concentrations ranging from 0 S ppb in MW1D to 1,700 ppb in MW1 MTBE was reported in the samples collected from wells MW6 and UH7 at low concentrations of 2 1 ppb and 0 S ppb, respectively TBA was detected in sample collected from well MW3 at a concentration of 13 ppb No other oxygenates or additives were detected Analytical results for oxygenates and additives are summarized in Table 3 Attachment C contains laboratory reports and chain of custody documentation SUMMARY All site monitoring wells were sampled Concentrations of petroleum hydrocarbons in the shallow, onsite monitoring wells were similar to those recorded in the past However, . concentrations of TPHg and BTEX in deep well MW 1 D have shown a dramatic decrease from previous monitoring events TPHg, ethylbenzene and xylenes have been non-detect in MW 1D G 1GROUNDZEIHARRYS\Repores\QMR1200513QM2005a doc