The Environmental Protection Agency is reviewing documents for cleanup of two sections of the West Lake Landfill in Missouri.
Both documents were filed in March by the potentially responsible parties for remediation of Operable Unit 1 (OU-1) and Operable Unit 2 (OU-2) of the Superfund property near St. Louis, according to an April update from the EPA.
The draft design investigation work plan for OU-1 will provide details of investigations needed to complete design for the cleanup approach set in a 2018 update to the 2008 record of decision on remediating West Lake. Approval of a revised work plan for remedial design of OU-2 would enable property owner Bridgeton Landfill to begin the actual design under a 2008 record of decision.
Operable Unit 1 is the radioactively contaminated portion of the 200-acre West Lake Landfill, resulting from the use as trash cover of 39,000 tons of surface soil mixed with 8,700 tons of leached barium sulfite residues. The potentially responsible parties are Bridgeton Landfill, Cotter Corp., and the Department of Energy.
The selected cleanup remedy involves extracting radiologically impacted material down as far as 20 feet in the contaminated zones. Soil contaminated at levels above 52.9 picocuries per gram would largely be removed to a depth of 12 feet. In certain sections material with concentrations above 52.9 picocuries per gram will not be removed at depths of 8 to 12 feet. Following completion of excavation, an engineered cover would be placed atop the impacted area. This work is forecast to cost $205 million over three years, paid by the potentially responsible parties.
In this month’s update, the EPA said its Region 7 office would review and submit comments on the draft design investigation work plan. It would be made pubic after the agency submits comments to the potentially responsible parties.
