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�. u .!'' ' � - _ - ♦-,tea. _ _ .; <br /> 20 )anuary 1998 <br /> • ' AGE-NC Project.No. 95-0109 <br /> 2.of 4 ± <br /> of 18%hydrochloric acid as a preservative. The samples were stored and-,transporied in a chilled ' <br />' container to.McCampbell Analytical; Inc. {MAI), in Pacheco, California, under chain-of-custody: <br /> All-samples were analyzed for total-04 6leum hydrocaibons quantified_as gisoline'(TP.H-g) in <br /> accordance with EPA method-5030/8015m, for.volatile organic compounds-(benzene,•toluene, <br /> 'eth The x lenes BTE&X in,accordance-with EPA method 602 'and for.volatile or anic <br /> Y , Y ) . g <br /> ,compounds with oxygenated compounds in accordance with EPA method 8260. <br /> Samples were also collected from MW-9 and MW-14 and placed in 40-mI.VOA vials with no added - <br /> preservative. These,two samples were,placed in a'chilled container and.transported under chain-of- <br /> custody to A. Keith Kaufmah-,-M.S.;in Culver City, California. These samples were analyzed for , <br /> physicochemical properties and microbiological enumeration. - <br /> 3.0, FINDINGS ,. <br />' 3.1.. GROUND WATER GRADIENT AND DIRECTION <br /> 'The depth'to-ground water ranged from-55.2 feet below surface grade (bsg) north of the site.to.57.2. <br /> 1 feet bsg south of the site: The data indicates'an average of J.12 feet increase of ground water <br /> elevation since September 1997. Ground water elevations are summarized-on Table 1. Ground water <br /> levels fell within the screened intervals,of the wells sampled. <br /> Ground water elevation contours" ased_upon data collected on.1'6 December I997;are depicted in <br /> Figure 3. The flow'direction is toward the south-and;as.in monitoring <br /> previous .events;the gradient <br />' stee �ens south of the site. <br /> '32. MICROBIOLOGICAL ACTIVITY IN GROUND WATER ; <br />'1 Microbiological,plate counts increased in the groundwater sample collected from MW-9'duiing the . <br /> "fourth�quarter,of 1997: General'plate 'counts decreased in MW-14; while selective degraders` <br /> increased slightly.,Nutrient concentrations generally increased slightly in-MW-9 and decreased <br /> 1' `sli htl 'in MW-14: Absolute numbers of both platecounts and nutrients remain below optimum, <br /> levels. r <br />' Total nitro en,concentrations, of ,100 .'arts per million .'m) aze optimum for maxiriium <br /> . g _ P P (ppm) _ <br /> biodegradation,and concentrations of 1.0 to 30 ppm are adequate,for to maintain biodegradation: The { <br />�► 2.3 ppm and'9.8 ppm total nitrogen-in the two samples analyzed indicate that site conditions-are less <br /> • than suff cient' to promote -significant• biologic breakdown of the hydrocarbon'.contaniinants. <br /> Chemical and microbiological data for ground water are summarized on Table 2 andlable-3.The <br /> Adv¢need GeoEnvironmental,Inc. <br />