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i <br /> i <br /> • How clean does the remediated soil have to be before it may be returned to the <br /> iexcavation? What is the risk to groundwater or personal contact with the soil in the <br /> future? When does the slowing rate of diminishment of hydrocarbons no longer justify <br /> bio-remediation? Reduction to contamination levels to less than 400 ppm is usually <br /> achievable While soil spread on the surface is bung remediated, further reduction may <br /> ' be achievable but a goal of reduction to non-detectable hydrocarbons levels in the soil <br /> may neither practical or of value to the future beneficial use of surrounding soil or <br /> ' underlying ground water <br /> 1 The exposure to rainwater accumulation in the excavation and interference with future <br /> scheduled product handling in the immediate excavation area is of concern to the owner <br /> and staff All excavated areas are proposed to be back filled no later than 15 November <br /> 2004 No hydrocarbon contaminated runoff will be allowed to exit the site in keeping with <br /> ' the existing Industrial Storm Water Pollution Prevention Plan and permit <br /> Lateness in the season of the excavation start and unknown extent of contamination <br /> beneath the aboveground storage tanks, suggest that the most contaminated zones be <br /> excavated and their perimeters explored at this time Following initial excavation this year <br /> ' an economic determination will be made of the feasibility of continued excavation next <br /> Spring, maintaining the existing tankage facilities or expansion of the project if warranted <br /> iAt that time we should have a more realistic appraisal of the extent of contamination, <br /> suitability of on site bio-remediation and a long term forecast of property uses The <br /> workplan will be updated to reflect the gathered information and mitigation effort will be <br /> ' continued <br /> ' 4-3 <br />