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: Working To Restore Nature =r:s .;., Criterion 1. -� The excavation and groundwater extraction alternative (Alternative 1) would increase the exposure of humans somewhat (construction crew) by bringing impacted media to the surface, causing exposure to dust created during excavation, and dermal exposure to the contaminants from impacted soil and groundwater during excavation activities. However, personal protective equipment would mitigate effects of short term exposure. The in-situ enhanced bioremediation alternative (Alternative 2) would provide good protection of human health by keeping contaminants in the subsurface, but the beneficial uses of groundwater would be threatened for a longer period relative to Alternative 1. Criterion 2. Alternative 1 would effectively eliminate the majority of contaminants from site soils and would reduce future impact on groundwater at the site by removing the source of contamination. Subsequent to excavation, on site bioremediation or incineration would reduce the toxicity, mobility, and volume of contaminants. Disposal of excavated soils by landfilling would reduce the mobility but not the toxicity or volume of contaminants. Extraction of groundwater from f the excavation would reduce the levels and volume of contaminants in the area of highest concentrations. Subsequent treatment of extracted groundwater using granular activated carbon would reduce the mobility and volume of contaminants but not the toxicity. Treatment of I extracted groundwater by direct discharge to the sanitary sewer would temporarily increase the mobility of contaminants while en route to the treatment plant, but would ultimately reduce the - volume and toxicity via treatment at the plant. Alternative 2 would also reduce toxicity, mobility, and volume of contaminants, but at a reduced rate, relative to Alternative 1. Criterion 3. The short term effectiveness of Alternative 1 is considerable because it results in the direct removal of the contamination source, and at least partial removal of the impacted groundwater. F The short term effectiveness of Alternative 2 is negligible because contaminants remain in the r... subsurface. r ; Criterion 4. The long term effectiveness of either alternative should be considerable. If�3 Criterion 5. Either alternative could be implemented within regulatory guidelines. f. Criterion 6. Alternative 1 is likely more cost effective than Alternative 2 due to the unpredictability of the in-situ enhanced bioremediation approach and the timeframe necessary to reduce relatively high ,.r levels of hydrocarbons by natural means. Criterion 7. }' Alternative 1 has few implementability problems. However, logistical problems include r:• W03651REPORTSICAP0294.FNL 6 �r