ARCHIVED REPORTS_XR0010284 - Laserfiche WebLink

Home Browse Search

SNTH The casings de th to water measurements and the elevations of the wellable 1 were used to P (T ) evaluate the groundwater flow direction and gradient beneath the site (refer to attached Field Procedures) Groundwater elevation beneath the site rose an average of 6 88 feet since December 30, 1994 The groundwater gradient magnitude and direction was generally consistent during the reporting period The calculated average gradients for January (0 0053 ft/ft), February (0 0044 ft/ft), and March (0 0058 ft/ft) are depicted on Figures 3, 4 and 5, respectively. Groundwater flow direction was to the northeast during the reporting period. On March 23, 1995, groundwater samples were collected from wells MW-1 through MW-5 for laboratory analyses The field methods used are presented in Attachment 1 Field purge logs are included in Attachment 2 Groundwater samples were analyzed by Sequoia Analytical for total purgeable petroleum hydrocarbons (TPHg) using Environmental Protection Agency (EPA) Method 8015 modified, total extractable petroleum hydrocarbons (TPHd) using EPA Method 8015 modified, and benzene, toluene, ethylbenzene, and total xylenes (BTEX) using EPA Method 8020 Copes of the laboratory reports and chain of custody documentation are included in Attachment 3 Results of laboratory analyses indicated dissolved TPHg was detected in the samples from wells MW-1 and MW-2 at 830 parts per billion (ppb) and 51 ppb, respectively. The TPHg in well MW-2 was reported by the laboratory as an unidentified hydrocarbon <C8. No TPHg was detected in any other site monitoring wells BTEX constituents were detected in well MW-1, most notably benzene at 59 ppb Hydrocarbon constituents detected in well MW-1 generally decreased an average of 38% since December 1994 However, toluene increased 19% in the well over the same penod No BTEX constituents were detected in any other site monitoring wells TPHd was detected in wells MW-1 and MW-5 at 300 ppb, and 250 ppb, respectively. The laboratory results of TPHd were reported as unidentified hydrocarbons in the C9-C24 range No TPHd was detected in any other site monitoring wells. No petroleum hydrocarbons were detected in monitoring wells MW-3 or MW-4 Results of laboratory analyses are summarized in Table 2 SUMMARY AND RECOMMENDATIONS The groundwater flow direction and gradient were generally consistent with those evaluated during previous events Hence, fluid levels will be monitored on a quarterly basis Dissolved gasoline hydrocarbons were detected in the samples from wells MW-1 and MW-2 Dissolved 38009 I OUQSR95doc 2