ARCHIVED REPORTS_XR0008388 - Laserfiche WebLink

Home Browse Search

I letter, that the Site was assigned to the PHS/EHD Local Correction Action Program for oversight of the UST issue In their letter, the PHS/EHD requested additional groundwater data be collected to further evaluate Site conditions To comply with the PHSIEHD request, additional groundwater monitoring was conducted and is described below 12 May 1993 Sampling Event On 12 May 1993, a groundwater sample was collected from Well MW-1 and analyzed for the presence of TPH-G, TPH-D, BTEX The groundwater sample ' was also tested for dissolved lead as was requested by the PHSIEHD During this sampling event, a sample was to also be collected from downgradient well MW-5, however, the well cover had corroded and could not be removed Laboratory results from well MW-1 indicated ' low concentrations of TPH-G and TPH-D (6 mg/L and 17 mg/L respectively), BTEX and lead were not detected Because well MW-5 could not be opened and sampled, Kennedy/Jenks recommend the MW-5 well cover be repaired and Wells MW-1 and MW-5 sampled the tfollowing quarter 30 August 1993 Sampling Event On 30 August 1993, the well MW-5 well cover was ' repaired and wells MW-1 and MW-5 sampled Low concentrations of TPH-G and TPH-D (6 3 mglL and 31 mg/L, respectively) were detected in well MW-1 Laboratory results did not indicate the presence of chemicals of concern in well MW-5 Groundwater elevation data ' collected during this sampling event indicated the groundwater flow direction had shifted from its historically northerly direction towards the west Discussion with the PHSIEHD indicated that the shifting of flow direction in the vicinity of the Port of Stockton is not unusual Results of this sampling event were submitted to the PHSIEHD in a letter dated 17 September 1993 This letter included a recommendation for collection of groundwater samples from well MW-1 for three additional quarters and for collection of a groundwater ' sample from wells MW-2, MW-3, or MW-4 if they were determined in the field to be the downgradient well at the time of sampling As agreed to with the PHSIEHD groundwater samples were only analyzed for the presence of TPH-G and TPH-D BTEX was not selected for analysis as BTEX had not been detected in well MW-1 during the last sampling event ' Including the 12 May 1993 sampling event, this would result in the collection of water quality data from well MW-1 for a total of five consecutive quarters Because groundwater level data was not obtained during the 12 May 1993 sampling event, the 30 August 1993 sampling event was counted as the first quarter of the monitoring program In November 1993, PHSIEHD submitted a letter to Ms Whitworth approving the proposed ' groundwater monitoring program 9 December 1993 Sampling Event The second quarterly groundwater sampling event occurred on 9 December 1993 Because of the fluctuating groundwater flow direction observed during the previous sampling event, the groundwater flow direction was calculated in the field Well MW-5 was determined to be the downgradient well from well MW-1 and as ' previously agreed to by the PHSIEHD, only MW-1 was sampled Only TPH-G (1 6 mg/L) was detected in well MW-1 during this sampling event A letter report, dated 7 January 1994, transmuted the results of this sampling event to the PHSIEHD Based upon the results and subsequent discussion with the PHSIEHD, a recommendation to reduce the groundwater 92254000 4 922540 00 04126194 2 28pm I