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Record of Decision System (RODS)



Address:  500 N BANKSON STREET 
City & State:  ST. LOUIS  MI  48880
County:  GRATIOT
EPA ID:  MID000722439
EPA Region:  05
NPL Status:  Currently on the Final NPL
ROD Type:  Record of Decision
ROD ID:  EPA/541/R-99/161
ROD Date:  02/15/1999
Operable Unit(s):  02
Media:  Other, Sediment
Contaminant:  Base Neutral Acids, Metals, Pesticides
Abstract:  The Velsicol Chemical Site is located in St. Louis, Michigan near the Pine River. The site is approximately 52 acres that was once occupied by a chemical processing plant. The chemical plant operated from 1936 through 1978 and manufactured a variety of organic and inorganic chemicals. In 1982 Velsicol and the State of Michigan entered into a consent decree where they agreed to contain in place the 52-acre main plant site where the former chemical plant was located. The site is now covered with shallow-rooted grass, and, to restrict access enclosed by a chain link fence. There are two operable units (OUs) at the Velsicol Site. OU1 consists of the approximately 52-acre main plant site, the location of the former chemical manufacturing facility. OU2 consists of contamination in sediments and fish in the lower and middle basins of the St. Louis Impoundment of the Pine River. The site was place on the National Priorities List in September 1983.


OU2 deals with the Pine River sediments and fish contamination. A 1988 preliminary health assessment prepared by the State and the Agency for Toxic Substances and Disease Registry (ATSDR) concluded the river poses a potential public health concern because of possible human exposure to contaminants via ingestion of fish and direct contact with river sediments. This concern was reiterated in 1993 in a State/ATSDR site review and update. Contamination of fish in the river was addressed by health advisories issued by the State. A no consumption advisory for all species of fish was initially published in 1977 and is presently in effect. The advisory affects 33 river miles of the Pine River. The OU1 remedy, which consisted of a 2-foot thick, low permeability slurry wall around the 52-acre facility and a 3-foot thick, low-permeability, clay cap was designed to prevent the migration of contaminants to the Pine River. A report published in October 1997 found that the clay cap was leaking because there is no frostprotection layer on top of the cap. EPA signed an Action Memorandum in June 1998 for a removal action which consisted of the dredging/excavating sediments containing 3,000 ppm total DDT or greater disposal of at an off-site facility. A Record of Decision addressing OU2 was signed in February 1999.
Remedy:  The selected remedy consists of Alternatives 4,5, and 6: Hydraulic Modification of the Pine river Excavation of Sediments, Dewatering and Water Treatment and disposal in a Resource Conservation an Recovery Act (RCRA) Subtitle D or C landfill. EPA recognizes that installation of temporary coffer dams may not be implementable in all locations in the St. Louis impoundment and therefore some of the sediment removal may need to be completed using mechanical or hydraulic dredging (Alternatives 2A or 3A).

Temporary coffer dams will be placed in the St. Louis Impoundment, water will be pumped from the cofferdam, all contaminated sediments greater than 5 ppm total DDT will be excavated, a stabilizing/drying agent will be added and wastewater will be treated prior to discharge to the Pine River. The water treatment will be designed to meet surface water discharge requirements and will probably consist of clarification, sand filtration, carbon filters and 1-micron bag filters. Monitoring of resuspension will be conducted directly downstream of the excavation operations. Air monitoring will also be conducted. After completion of the dredging project sediment samples will be collected to ensure the clean-up standard has been met. The State of Michigan will continue to monitor fish levels. Excavated sediments will be transported by truck to either a RCRA Subtitle C or D landfill for disposal.

Estimated Capital Cost: $20.1 Million (Subtitle D)
$34.3 Million (Subtitle C)
Estimated Annual O&M Cost: $0
Estimated Present Worth: Not Applicable
Text:  View full-text ROD [ 306K ]
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