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(ppb) ) for TPHG, MTBE and BTEX are shown in Table 1. The values <br /> for MTBE are not detectable (ND) . The detectable limits for MTBE <br /> in these analytical determinations are limited due to the <br /> interference caused by the very high concentrations of TPHG in the <br /> groundwater samples. Laboratory Data Sheets with detection limits <br /> and a copy of the Chain of Custody (COC) are contained in Appendix <br /> B. <br /> SUMMARY, CONCLUSIONS AND RECOMMENDATIONS <br /> The calculated gradient is S 646 W or 2440 at 0.01 ft/ft. This is <br /> a generally southwesterly gradient. The direction and slope are <br /> southwesterly as was found in the majority of the prior calculated <br /> gradients. <br /> A review of the soil and groundwater date indicate that the <br /> contamination still remains in the soil and consequently the <br /> groundwater from the former UST pit area in a southwestern <br /> quadrant. The concentrations are still high in the groundwater <br /> collected from the three wells on site. <br /> Based on the analytical data from this and prior quarterly reports, <br /> it appears that no or very low detectable concentrations of MTBE <br /> are impacting the groundwater at this site. <br /> The groundwater beneath the site has been impacted and heavy <br /> gasoline and BTEX contamination were detected in the groundwater <br /> samples from MW-1 and MW-2 . Consistent with prior results , very <br /> low concentrations of gasoline and BTEX were detected in the <br /> groundwater from MW-3. <br /> JPCA recommends that the further characterization of the area in <br /> the quadrant commencing at the former UST pit and continuing in the <br /> southwestern direction be further characterized by sampling the <br /> soil and groundwater using a hydropunch technique. A well survey <br /> for wells within a � mile radius of the subject property is also <br /> recommended. A detailed workplan and cost estimate would be <br /> prepared as separate documents. <br /> JPCA recommends continued monitoring of the wells to further <br /> evaluate the amount of contamination and consistency of the <br /> gradient. <br /> The results of the hydropunch work, a regional well survey, <br /> gradient determination and monitoring well sampling should give <br /> sufficient data as to what remediation action, if any, should be <br /> performed <br /> This report has been prepared specifically for Messrs. Joseph P. <br /> Eger and Paul Wnuk of SIERRA LUMBER MANUFACTURERS, with specific <br /> application to a hazardous waste investigation. The report has <br /> 4 <br />