ARCHIVED REPORTS_XR0009737 - Laserfiche WebLink

Home Browse Search

n • In August 1993, wells MW-1, MW-2, and MW-3 were monitored and sampled Analytical results showed that MW-1 had no measurable concentrations of petroleum hydrocarbons in the groundwater Wells MW-2 and MW-3 contained detectable levels of petroleum hydrocarbons A program of quarterly groundwater monitoring and sampling was begun in March 1994 In August 1995, Smith Technology conducted a subsurface site investigation to further define the extent of contamination in groundwater at the site Smith Technology supervised the installation of monitonng wells MW-4, MW-5 and MW-6 These three new wells were developed and sampled along with monitoring wells MW-1, MW-2, and MW-3 Analytical results of groundwater samples from the six monitoring wells indicated the presence of elevated concentrations of petroleum hydrocarbons in the vicinity of wells MW-3 and MW-6, on the northeast comer of the site SAMPLING ACTIVITIES On October 1, 1997, groundwater samples were collected by Smith Technology personnel from monitoring wells MW-3 and MW-6 The locations of the monitoring wells are shown on Figure 2 Prior to collection of groundwater samples, the depth to water, pH, electrical conductivity, and temperature were measured in the monitoring wells and recorded A minimum of three well casing volumes were purged from each well prior to sampling The wells were allowed to recover and samples were collected from each well using dedicated disposable bailers The groundwater samples collected from each well were submitted to American Environmental Network laboratory (FLAP cert no 1172) for analysis of total petroleum hydrocarbons as gasoline (TPHg), and benzene, toluene, ethylbenzene, and xylenes (BTEX) utilizing EPA methods 801518020, and oxygenate fuel additives utilizing EPA method 8260 Groundwater samples were also analyzed for ethyl dibromide at the request of Ms Mary Meays Groundwater well purge and sample logs are contained in Attachment 1 ANALYTICAL RESULTS Petroleum hydrocarbon constituents were detected above laboratory method detection limits in the samples collected from wells MW-3 and MW-6 MTBE was detected in well MW3, although MW3 had a higher detection limit due to dilution factors No other oxygenate fuel additives were detected in the sample from well MW3 No oxygenate fuel additives were detected in the sample from well MW6 A summary of analytical results is presented in Table 1 Laboratory data sheets and chain-of-custody documentation are contained in Attachment 2 WELL RESURVEY On October 30, 1997 the wellhead elevations were resurveyed by Smith Technology personnel The wellhead elevation of well MW2 was found to be 0 63 feet lower than the original survey elevation performed by Aqua Geosciences, Inc This may have been due to an error in survey, calculations, or the numbers were mistyped in their report • w 1943731quartlyl4gr-1997 doc 2 • SMTH