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LOF Glass Woodward-Clyde Consultants May 6, 1985 Page 5 other sources (nonpoint) . Under declining water table conditions, oil will typically become trapped in the pore spaces of the substrate thereby continually depleting the quantity of oil on the groundwater surface until it all becomes immobilized in the vadose or unsaturated zone. It is likely that this process has occurred here, explaining the absence of oil in the wells (with the possible exception of Well 10. ) Being located adjacent to the spill site, Well 10 would be expected to contain at least a small quantity of oil. The fact that it does not may be an indication that siginficant migration of the spilled material on the water table did not occur. Analytical Results The lab analyses of water samples from Wells 1, 2 and 6 through 11 revealed the presence of very small amounts of dissolved hydrocarbons in Wells 1 and 9 and minor amounts of suspended oil in Wells 1, 9, 10 and 11. The results of the analyses are shown in Table 2. These concentrations are within background levels which may be expected in shallow groundwater at an industrial site and may or may not be related to the spill. Conclusions Approximately 3,250 gal. of oil has been recovered to date and represents a substantial percentage of the total quantity spilled. It is probable that some free oil still exists on the water table but that much of the remaining oil is trapped in the soil around the leak site. Some of this immobilized oil may remobilize when the water table rises next winter. Recommendations Based on the data and conclusions presented above, we do not feel that any additional remedial actions are currently necessary other than to deepen the sump to permit continued operation of the recovery system and possibly excavate the most heavily contaiminated soil still in place