ARCHIVED REPORTS XR0000966 - Laserfiche WebLink

Home Browse Search

75. h �':a.-. »... 'aY%a s <�.•.<:G.. :i'. S'. ?'. .2 .a.C'�r...3 F a.',-[Y '•1:...t,-�h • • r r • r n ' 7. 29 Septembei-:2000 • ;AGE-NC''Pr'oj'ect No. 99-0657` Page 2 of 4 j . ' Analytical, Inc. (MAI);'a California.Department'of-Health Services.(DHS)-certified analytical laboratory in Pacheco, California.'Each sample`was.analyzed for: ' Total petroleum hydrocarbons .• - . I ' ` • � ��` � .quantified as gasoline' and diesel.{TPH-g and TPI3-d, .� r respectively) by EPA Methods 8015M/3550/5030; Volatile'aromatic.compounds: benzene; toluene;'ethyl benzene and xylene (BTE&X)with methyl-tertiary butyl ether (MTBE) by EPA,Method 8020; 3A: FINDINGS' ' 3.1. GROUND WATER GRADIENT AND FLOW DIRECTION• . ; The elevation of ground water in each well was calculated by"subtracting the depth to ground water I from the surveyed well casing elevations (Table.1). . ; Depths to groundwater ranged from.11.85 feet.to 12.68 feet below the well casing tops. Ground water elevations at the site ranged from 27.62 feet above mean sea level (MSL) in_well MW3 to 28.61 feet above MSL;-in well MW 1: IThe ground water flow, direction was calculated using ground water elevation data.The ground water ' at the site is-flowing to"the north-northwest'with an average.hydraulic gradient of 0.008 feet/feet. I r Figure 3 illustrates,the ground water•elevation contours 3.2. GROUNDWATER ANALYTICAL.RESULTS " • .TPH=g wa only detected•iri the water samples collected'from monitoring r`niells MW-5,and MW-6 ; at concentrations.'of 11;000 mic'rograms per liter (µg/l)`and 5,100:'4g/l,'respectively. TPH-d was detected in the wafersamples collected from monitoring.wells MW 1,MW-2-'MW-5 and MW-6 at concentrations as'high as 3;600 p g/1 in MW-6.` Benzene was detected in.samples MW-2 and_MW=S at'7.7 µg/1 and 690 µg/1; respectively,. The remaining;BTE&X compounds �wdre only detected in samples MW-2, -MW-5 .and 'MW-6 at conceritrationsrranging from below.detectable limits (toluene and xylenes.iniMW 2) to 1;300 µg/l . of xylenes in MW-5.'MTBE'was riot;detected'abovelaboratory reporting limits in any of the ground Is e ted and analyzed'water, amples'collec .r I.. G Advanced GeoEnvironmental,Inc.