Laserfiche WebLink
VI. Discussion <br />The groundwater data appear essentially similar between the current monitoring <br />and sampling to Dames and Moore's initial well sampling in 1991. The 1991 <br />groundwater flow direction was southeasterly and the current flow direction is <br />south-southeasterly. <br />The following groundwater data comparisons are presented in Table 4. Dames <br />and Moore apparently performed the background on only recent sampling Wells <br />MW-1 and MW-4 on Parcel 3. The data available from that report is presented <br />with the TRE data. Only one, very low detection of Chyrsene was detected in <br />well MW-3. All other PAH compounds were not detected. <br />Table 4. Comparison of Dames and Moore and TRE Groundwater Sampling <br />Data <br />COMPOUND <br />IN <br />GROUNDWATER <br />MW-1 <br />DAMES <br />AND <br />MOORE <br />MW-4 <br />DAMES <br />AND <br />MOORE <br />MW-1 <br />TRE <br />MW-2 <br />TRE <br />MW-3 <br />TRE <br />MW-4 <br />TRE <br />1991 data 1991 data 2003 data 2003 <br />data <br />2003 data 2003 data <br />Sulfur (mg/I) 146 153 197 587 466 488 <br />Sulfates (mg/I) 410 440 597 1780 1412 1478 <br />PAH (ug/I) all ND all ND all ND all ND (chrysene) <br />17* <br />all ND <br />Copper (mg/I) <MCL <MCL ND ND ND ND <br />Nickel (mg/I) <MCL <MCL ND 0.4 ND 0.3 <br />Vanadium (mg/I) <MCL <MCL ND ND ND 0.08 <br />- all other parameters were not detected. No data available for Wells MW-2 and MW-3 from Dames <br />and Moore. <br />Dames and Moore only reported metals data as less than MCL in 1991. <br />August 2000 Water Quality Goals: MCL for Chrysene- none; Copper-1,300 ug/1 ; Nickel- 100 ugh; <br />Vanadium- none; Sulfate- none. <br />Dames and Moore background soil data showed concentrations of sulfur and <br />sulfates present in the soil samples near the surface and at depths of 10 feet at <br />680 and 190 milligrams per kilogram (mg/kg) at MW-1 and MW-4 respectively. <br />Dames and Moore groundwater data showed sulfur at 146 milligrams per liter <br />(mg/I) in MW-1 and 153 mg/I in MW-4 in 1991. Sulfate was 410 mg/I in MW-1, <br />400 mg/I in MW-3, and 440 mg/I in MW-4 in 1991. Sulfur and sulfate data from <br />the TRE sampling show higher concentrations in Well MW-4, but the overall <br />trend compares relatively well to the previous ground water and soil data. Since <br />Dames and Moore did observe sulfur and sulfate in soil and groundwater during <br />the well installations, it is unclear just how much contribution of soil sulfur/sulfate <br />to groundwater occurs. In particular, TRE notes that the highest sulfur value was <br />measured at 1,260 mg/kg in sample MW-2B (10 feet deep) and 737 mg/kg in soil <br />samples taken at MW-1B (0.5 feet deep) in Dames and Moore's report of <br />8