US EPA releases reports on St. Louis clean-up - links here!
The Feasibility Study for Operable Unit 3, or OU3, is now available. Click CH2M - FINAL FOCUSED FEASIBILITY STUDY FOR RIVERBANK AND FLOODPLAIN SOILS (73 pp, 5.53 MB) to read the report. Note that the No Action alternative is required under the Superfund law. EPA expects to release a Proposed Plan for public comment this spring. EPA will choose a final remedy using nine criteria described in the Superfund law, which also includes evaluating public comments. The final remedy decision will be documented in a Record of Decision and includes a Responsiveness Summary that responds to public comments.
Farther downstream in the Pine River, Operable Unit 4, or OU4, is currently being studied and a future remedy decision will be made once the study is complete.
Velsicol Plant Site – In-place Thermal Treatment
EPA has finished the third and final phase of in-place thermal treatment at the former chemical plant site. The third 1.5 acre phase removed over 140,000 pounds of site contaminants from soil and groundwater. Much of the contaminant removal was highly contaminated liquid waste called non-aqueous phase liquids. The total amount of contaminants removed from the four acres was 382,000 pounds.
Velsicol Plant Site – Future Design and Construction Activities on the Plant Site
The next phase of the Velsicol site cleanup is the excavation and off-site disposal of approximately 100,000 tons of contaminated soil in the former plant site. EPA will partner with the United States Army Corps of Engineers to provide oversight of the excavation and off-site disposal. The document detailing the design for the cleanup can be found here, CH2M HILL - BASIS OF DESIGN REPORT (FINAL) - PSA-1 & PSA-2 EXCAVATIONS, OU1 (625 pp, 25.14 MB).
Velsicol Plant Site - Remedial Design Investigation of the Upgradient Slurry Wall
EPA is continuing its investigation of the upgradient slurry wall to evaluate the slurry wall effectiveness. Initial results are presented in CH2M - DATA EVALUATION REPORT (178 pp, 11.12 MB).
The next phase of the upgradient slurry wall investigation is described in the work plan, CH2M TECHNICAL MEMORANDUM - SUPPLEMENTAL UPGRADIENT SLURRY WALL INVESTIGATION PLAN (38 pp, 2.08 MB) . Once the this phase of work is complete, data will be evaluated to determine the next steps.
Velsicol Plant Site – Bathymetric Survey
This spring, EPA will begin to map the bottom of the Pine River adjacent to the site to inform the design of the downgradient vertical barrier wall. Click CH2M TECHNICAL MEMORANDUM - BATHYMETRIC SURVEY INVESTIGATION WORK PLAN (29 pp, 4.27 MB) to read the work plan.
Velsicol Burn Pit Superfund Site
The Velsicol Burn Pit site has received infrastructure funding and work is underway to start cleanup activities. Additional information can be found by visiting www.epa.gov/superfund/velsicol-burnpit.
Climate Change
The EPA Superfund program has released guidance on how climate change may influence remedy decisions. Visit Superfund Climate Resilience | US EPA to learn more.