ARCHIVED REPORTS_XR0007168 - Laserfiche WebLink

Home Browse Search

Laboratory analysis of groundwater samples for MTBE, TBA, DIPS, ETBE, TAME, and napthalene ' indicated detections of MTBE The sample from well MW-3A contained MTBE above detection limits at a concentration of 1,300 pg/L Other results indicated less than detection limit concentrations of MTBE ' that ranged from <2 to <2,000 Other oxygenate analytes were not detected above method detection limits 1 3 2 MARCH 2901 MONITORING EVENT 13.2.1 Groundwater Measurements—March 2001 On March 17, 2001, Blaes Environmental measured the depth to groundwater in 23 groundwater monitor ' wells casings associated with the site Groundwater levels were measured with the same method as described in Section 3 1 1 The water level depth and measurement time were recorded on a field data ' sheet by the field technician The field data sheet for the March 2001 monitoring event is included in Appendix D and the measurements are presented in Table 3 Groundwater depths recorded in March 2001 ranged from 50 84 feet bgs at MW-413 to 53 10 feet bgs at lieMW-2 These measurements indicated that the groundwater level rose approximately 1 5 feet compared to the December 2000 groundwater levels Even with this groundwater rise, the upper wells ("A" casings) did not contain groundwater in March 2001 These wells are indicated as "well dry" on Table 3 Depth to groundwater measurements corresponded to groundwater elevations ranging from 26 36 to 26 79 feet below mean sea level No free-phase hydrocarbons were observed during collection of groundwater level measurements The data from the middle well casing containing water were used to I create a groundwater surface map showing the groundwater flow direction across the site The average groundwater flow direction as of March 17, 2001 was inconclusive since the groundwater surface was Irelatively flat Blaes Environmental technicians also collected dissolved oxygen level measurements from each well casing using a YSI-85 dissolved oxygen meter Measurements indicated that dissolved oxygen levels in groundwater ranged from 0 3% at monitor wells MW4 and MW-6 to 412% at monitor well MW-8 Dissolved oxygen levels above 10%were observed at monitor wells MW-3, MW-5, and MW-8 (Table 3) 07/10/01 Blaes Project#002-70950-02 1 bjm C 1BLAESIU-Hau1170950170950r101 doc