ARCHIVED REPORTS XR0009773 - Laserfiche WebLink

Home Browse Search

Bank of Stockton Page 2 Summer 1996 Quarterly Monitoring Report Project No 102 2 October 10, 1996 ' 1.2 Groundwater Sampling On September 3, 1996, depth to groundwater in three of the five monitoring wells was measured and one of the monitonng wells was purged and a groundwater sample was collected Mr Harlin Knoll of the San Joaquin County PHS/EHD which is the LOP agency, required that only the well MW-1 be purged and sampled Depth to groundwater in monitoring well MW-2 was not measured because a large number of wooden pallets were stacked on it, and monitoring well MW-3 was not measured because it was found to have been paved over with blacktop Wells MW-1, and MW-5 were also paved over, but the sampling technician was able to determine where they were and then chip the blacktop off the well boxes During the purging of MW-1, groundwater quality ' parameters were recorded are tabulated in the groundwater monitoring field notes (Appendix C) ' Due to unexpectedly high levels of BTEX compounds and gasoline range petroleum hydrocarbons in the sample collected from MW-1, the well was re-sampled on Septembet 16, 1996 ' 1.3 Groundwater Sampling Procedure p g e On September 3, 1996, Del-Tech Geotechnical Support arrived on-site, opened the wells MW-1, MW-4, and MW-5, and measured the depth to water with an electrically actuated ' sounding tape As each well was opened, and prior to taking the depth to groundwater measurement, a PID organic vapor meter was used VOC's in the head space of the well The water level reading was recorded to an accuracy of 0 01 foot In wells where free I floating product was suspected, a clear disposable bailer was used to gauge the interface No floating product was observed during this sampling event Stagnant water in the well casing was purged using a Grundfus electric submersible pump, and the rate of well purging was monitored Well MW-1 was purged of at least three casing volumes and then purged until the groundwater parameters (temperature, Iconductivity, and pH) had stabilized (Appendix C ) indicating that water, representative of actual aquifer conditions, was entering the well Groundwater parameter stabilization was characterized by three successive readings within 10% I On September 16, 1996, Del-Tech Geotechnical Support arrived on-site to re-sample P PP P well MW-1 for the purpose of verifying unexpectedly high levels of petroleum hydrocarbons which had been detected After the well was opened, a PID measurement was taken, and the depth to groundwater was measured as described above Stagnant water in the well casing was purged using a stainless steel bailer belayed with a servo actuated electric reel The rate of well purging was monitored The well was purged of at 2937 Veneman Ave ,#B240 Phase One Environmental Inc Phone (209) 569-0293 Modesto, CA 95356 Fax (209) 569-0295