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;�� 'S '�LaS. :� .� S 8: 7� �r � 3 �' fir•--•^ ;3 �3' •R � 9 tiYT The laboratory results for toluene, ethylbenzene, and xylenes were below State Maximum Contamination Levels (MCL's) in all _ wells tested. Free product (gasoline) was found in MW3 at thicknesses of 0.7 - 1.7 feet. The highest levels of dissolved hydrocarbon constitu- ents detected in the groundwater were found in wells MW6, MW7, and MW1. Benzene war. detected in all wells, except MWS, at levels above State MCL. Groundwater has been impacted beneath bath former tank pits and dissolved hydrocarbons appear to be spreading laterally in a westerly to southwesterly direction as indicated by the dissolved Pit A. and MW6 hydrocarbon concentrations in MW2, west of Tank and MW7 north and saest of Tank Pit B. Using the groundwater monitoring data (Table 4) a gradient map was created using a kriging program (Figure 5). During several monitoring episodes the groundwater gradient near the former tank pit A changed direction. The gradient during the first monitoring episode was in a northwesterly direction at 0.0013 ft/ft, but in subsequent monitoring the gradient shifted to the northeast at 0.0036 ft/ft. This gradient change may be due to tidal influence or local groundwater withdrawal or recharge effects. The gradient near the former tank pit B has been consistent with groundwater flow in a northeasterly direction at 0.0158 ft/ft. The steeper gradient for tank pit B area is most likely due to the effects of free product in well MW3. The divergence between n distribution gradient directions and the dissolved atternsuggests the g gradient periodically shifts from northeast to southwest. Because of the potential for tidal/river influence on gradients at this site event in the ordertidal to correlate groundwaterrecorded level fluctuations monitor- ing with surface water charges. 5.0 CONCLUSIONS AND RECOMMENDATIONS r. Further delineation of the lateral extentof $ recommended d anrowater contamination at the site is necessary. it that an additional round of groundwater monitoring and sampling be conducted to verify the initial results and to guide the place- ment of additional exploratory borings/wells. A phase II inves- tigation should be undertaken after reviewing the sampling/moni- toring data. Additionally, bailing of free product form well MW3 should be initiated. The amount of product removed and the recovery rate should be recorded after each bailing. 5