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{ 1 1 13 April 1998 AGE-NC Project No 95-0144 " Page 2 of 4 container, under chain-of-custody, to McCampbell Analytical, Inc (MAI) in Pacheco California k The samples were analyzed for total petroleum hydrocarbons quantified as gasoline (TPH-g), diesel (TPH-d), and motor oil (TPH-mo) in accordance with EPA Method 8015 modified for each ' hydrocaibon range, for volatile aromatic compounds (benzene, toluene, ethylbenzene and xylenes, BTE&X)in accordance with EPA Method 602, and for volatile organic compounds with oxygenated compounds in accordance with EPA Method 8260 , 1 30 FINDINGS ' 3 1 RELATIVE GROUND WATER ELEVATION AND GRADIENT The relative elevation of ground water in each well was calculated by subtiacting the depth to water from the surveyed casing elevation (Table 1) Ground water elevation increased an average of 3 49 feet between November 1997 and February 1998 The approximate hydraulic gradient for the current' ' monitoring period was calculated to be 0 010 ft/ft with a northerly flow direction Ground water N elevation contours derived from data collected on 04 Febivary 1998 are depicted in Figuie 3 Ground water was between four and six feet above the screened interval in monitoring wells MW-I MW-2, '• MW-4, MW-5 and MW-8 Ground water was approximately one foot above the screened interval in MW-11, MW-l2, MW-13 and MW-18 " 1 3 2 ANALYTICAL RESULTS OF WATER SAMPLES , During the February I998 monitoring, TPH-g was detected in monitoring well MW-1 at a concentiation of 450 parts per billion (ppb, repotted as micrograms per litei),,TPH-d was detected m vel Is MN's-1 MW-4 and M%V-12 at concentrations ranging from 61 ppb to 200 ppb TPH-mo was not detected in samples collected during the Februaiy 1998 monitoring event 1 1 ' BTE&X were detected in the sample collected from MW-I at concentrations of 4 0 ppb, 6 0 ppb, 17 ppb and 120 ppb, respectnely BTE&X were not detected in the remainin, samples collected Chloroform was detected to the samples collected from MW-8, MW-1 1, MW-I2 and MW-13 at concentration ranging from 1 I ppb to 9 0 ppb Seven volatile organic compounds were detected.in the sample from MW-I at concentrations ranging from 1 4 ppb to 39 ppb Bromodichloromethane ; ' was detected in MW-I I and NNW-12 at concentrations of 1 1 ppb and 1 0 ppb, respectively Sec- , butyl benzene and p-isoprop)]benzene were detected in MW-13 at concentrations of 1 7 ppb and 1 2 ppb respectively Oxygenated compounds «rete notrdetected in any ground water samples collected at the site , I Arhanced GtoEn1 ironmcntat,ine i n , 1