ARCHIVED REPORTS XR0011293 - Laserfiche WebLink

Home Browse Search

IGeoloywa[Technws Inc Page 3 Groundwater Monitoring Report Project No 4212 March 24, 1998 Extreme care was exercised while collecting samples to prevent agitation of the water contained in the bailer Water samples were transferred from the bailer into 40 ml VOA vials preserved with hydrochloric acid using a bottom emptying device which minimizes sample aeration during transfer of the sample All samples were checked for head space bubbles, labeled, inserted into foam holders and placed in an ice chest cooled to 4°C for transport to the laboratory Disposable gloves were worn by the sampling technician while collecting all samples A chain of custody document, listing all samples collected and their intended analyses, accompanied the samples from field to the laboratory, thereby providing a means to track their movement and insure their integrity 1.3 (Laboratory Analyses The groundwater samples collected on February 24, 1998 were delivered to Sherwood Lab (Department of Health Services Certification No 1400), of Hilmar, California, for analysis The samples were analyzed using the following methods o EPA method 602 - BTEX o EPA method 602 - MTBE o EPA method 5030/8015(m) -TPH-Gasoline The detection limits for the above analyses are listed in Table 3 of Appendix A and the lab data is presented in Appendix B 2.0 FINDINGS AND DISCUSSION One quarter inch of floating product was observed in MW-2 during this sampling event The laboratory analytical data from this monitoring event shows that gasoline range petroleum hydrocarbons continue to be detected in wells MW-1, MW-2, MW-4, MW-5 and MW-102 ' The results from the latest round of sampling are comparable with the results from the past monitoring events Concentrations in MW-1 showed a small increase from the last event Concentrations in MW-2 showed a significant decrease from the past monitoring event, down to levels similar to those seen in the Spring of 1997 Concentrations in MW-4 stayed relatively consistent with the past monitoring events MW-5 was consistent with the last monitoring event MW-102 showed a significant decrease since the last event and continues on a decreasing trend since its installation iMTBE was detected in MW-1 and MW-5, both wells were just above detection limits