Laserfiche WebLink
EXECUTIVE SUMMARY <br /> r <br /> Upgradient Environmental Consiiltaiits visited the Valley Motors dealership on May 10 to measure <br /> water depths and collect groundwater samples from the four on-site monitor wells The depth to <br /> groundwater has risen one foot since the last monitonng in February, and measurements in Jicate <br /> that groundwater continues to flow to the east The data indicate that the gradient is steeper in the <br /> northern part of the site near VM-4 than in the southern part of the site near VM-3 The di Terence <br /> appears to be related to the permeability of the water-bearing zone In the north, low-perm ability <br /> clay near the ground surface forms a slight confining layer, causing the static water surfact to be <br /> slightly deeper than in the southern part of the site <br /> After measuring the depth to groundwater,the wells were purged with a submersible grou,dwater <br /> pump and water samples were collected with disposable Teflon bailers, poured into 40-m1 Mals and <br /> I-liter amber bottles and preserved for laboratory analysis Excelchem Analytical analyzes the <br /> samples for TPH;gasoline using EPA method 602, for BTEX using EPA method 8020,and for five <br /> oxygenates using EPA method 8240B Cytoculture Environmental Biotechnology analyze. them <br /> for the abundance of total heterotrophic bacteria and hydrocarbon-degrading bacteria Arte r <br /> declining in February, hydrocarbon concentrations rose to more typical levels in VM-1 and VM-2 <br /> but remained below detection limits in VM-3 Concentrations also increased in VM-4, but were <br /> generally below the levels seen in the middle of 1998, when this well was drilled None of he wells <br /> contained detectable concentrations of any of the oxygenates, except for VM4, in which MTBE <br /> was again detected at a low concentration <br /> Hydrocarbon degrading bacteria and other hetertrophs are present in three of the four Nvells (few <br /> bacterial colonies were present in VM-4) This suggests that passive or enhanced bioremt-dation is <br /> a potential remedial technology that would be suitable at this site <br /> 1 <br />