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E R604 :UPDATE 11-JULY, 1992 <br /> { <br /> gradient from each well to all surrounding wells (difference in <br /> M ground water elevations/distance between wells ) , ie. MW1 to MW2 , <br /> MW1 to MW3 , MW1 to MW4 , MW1 to MW6 and MW1 to MW7 , etc . Depth to <br /> ground water data from MW5 is not used, this well was installed in <br /> a slant boring and produces anomalous highs when used. From these <br /> gradient lines data points representing the contact for the <br /> proposed contours are plotted along each individual line. Once <br /> the data points have been plotted between all the wells , the data <br /> points representing a given gradient elevation ( -45 foot contour , <br /> for example) are connected with site specific factors , ie. <br /> incorporating conditions caused by local geology, hydrogeology , <br /> r utility trenches , etc. , being used to control the contour between <br /> data points . <br /> After the depth to water measurements had been performed the well <br /> is purged for sampling. Water samples are obtained after purging <br /> r ' the well of enough water so that pH, conductivity and temperature <br /> E stabilize. The wells are purged using a dedicated, sterile <br /> disposable bailer (dedicated to each well) , removing the water <br /> until the well has been depleted or pH, temperature and <br /> conductivity measurements have stabilized ( 2 to 3 . 5 gallons ) . <br /> During the sampling of MW7 , approximately 4 gallons of ground <br /> ; water were purged prior to obtaining the sample. The well was <br /> then sampled using the same dedicated, sterile disposable bailer . <br /> The water sample is slowly drained from the bailer into the sample <br /> tsj � i{ containers . The "purged" water is "contained" on site, in a 55 <br /> gallon 17H drum, see Appendix A. <br /> •I 1 <br /> � ; Enough water was sampled from each well to £i11 4-40cc VOA vials , <br /> with no air space. All containers are fitted with a teflon lined <br /> air tight cap . These vials are then labeled with the sample <br /> location, date sampled, time sampled, analyses to be run, initials <br /> � If of the sampler , and preservative if used (no preservatives were <br /> used) , placed in a zip lock baggie and then placed in a cooler <br /> with enough ice to maintain the sample at 40C. Prior to leaving <br /> E � the site, a chain of custody form is filled out and the samples <br /> are then delivered the following day to MATRIX Analytical <br /> Laboratories (DHS#359 ) for Total Fuel Hydrocarbons and BTEX using <br /> EPA method 5030 and 602 . If samples are obtained for Fecal <br /> Coliform, they are hand delivered the same day to FGI <br /> Environmental , see Appendix A - Field Notes and Chemical Results . <br /> RESULTS - WATER <br /> Ground Water Gradient <br /> A ground water gradient map has been produced from the July 24 , <br /> 1992 depth to water measurements , Figure 4 . <br /> Figure 4 gradient shows flow to the northeast, from MW3 towards <br /> MW4 at a relatively flat gradient of 0 . 40 (0 . 6$ 1/1651=0 .004 ) . <br /> 01 <br /> page 2 <br />