Record of Decision System (RODS)
ORONOGO-DUENWEG MINING BELT
|Site Name:||ORONOGO-DUENWEG MINING BELT|
|City & State:||JOPLIN MO 64755|
|NPL Status:||Currently on the Final NPL|
|ROD Type:||Record of Decision|
Please note that the text in this document summarizes the Record of Decision for the purposes of facilitating searching and retrieving key text on the ROD. It is not the officially approved abstract drafted by the EPA Regional offices. Once EPA Headquarters receives the official abstract, this text will be replaced.
The Oronogo/Duenweg Mining Belt site (commonly know as the Jasper County site) is located in Jasper County, Missouri. The site is part of the Tri-State Mining District which covers approximately 270 square miles in southwestern Missouri, southeastern Kansas, and northeastern Oklahoma. Land use varies from agricultural to urban. Approximately 60,000 people live within the site boundaries, and the Environmental Protection Agency (EPA) has identified at least 650 residential homes that utilize shallow groundwater wells for drinking water supplies within the site.
Mining, milling, and smelting of lead and zinc ore date back to 1850 and continued in the district until the 1970s. Processing of the ore resulted in approximately 150 million short tons of wastes. The wastes currently contribute metals contamination to surface soils, surface water, and groundwater.
In 1991, EPA signed an Administrative Order of Consent (AOC) with a group of nine potentially responsible parties (PRPs) to conduct a Remedial Investigation/Feasibility Study (RI/FS) at seven of the eleven designated areas (DAs). EPA conducted the investigations at the remaining four DAs.
In December 1993, EPA issued a Unilateral Administrative Order (UAO) to the PRPs to supply bottled water to affected homes. In June 1994, EPA issued a second UAO to the PRPs to provide additional bottled water if wells were found to exceed health-based standards.
A Record of Decision (ROD) was completed in August 1996 addressing Operable Unit 2 (OU2). A second ROD was completed in July 1998 addressing OU4.
The selected remedy includes connecting approximately 348 homes to a public water supply.
Approximately 176 homes in the Oronogo/Duenweg (O/D) designated area (DA) are located within boundaries of Public Water Supply District (PWSD) #3 and will be hooked up to the district's water supplies. Another 19 homes are located very near the PWSD boundaries and will also be connected to the district's water mains. Eight homes are located along the western Webb City limits and will be connected to the Webb City public water system. Additionally, 117 households in the southwestern portion of the O/D DA and 28 households in the Iron Gates Extension (IGE) DA will receive public water from expansion of Missouri American Water Company's existing water supply distribution system.
Five homes will receive point-of-use treatment systems under the selected remedy. The proposed water treatment systems will consist of a sodium chloride charged residential water softener. In order to ensure that the point-of-use treatment units are maintained, functioning properly, and effectively reducing metals concentrations to safe levels, the Environmental Protection Agency (EPA) will establish a service contract with the treatment unit supplier to maintain the units until such time that public water becomes available for these homes. When public water supplies are economically available to these households, EPA will provide hookups to the public water supply.
The selected remedy includes a monitoring program to periodically monitor homes with shallow water wells that are threatened with exceedances but currently have acceptable drinking water levels and will not be connected to a public water supply system because of their distance from existing water mains. All homes within the affected areas not hooked up to public water or supplied with a treatment unit will be included in the program. The program will include households located within existing public water supply districts not currently hooked up to those systems. During the remedial design and planning phase, a sampling program will be implemented to sample homes outside the areas that can cost effectively be connected to public water supplies. The number of households to receive point-of-use treatment systems will be determined on the basis of these sampling efforts.
Institutional controls will ensure that new or existing wells with water samples exceeding safe drinking water, levels are not used for drinking water without prior treatment. Institutional controls may include restrictions on the drilling of new shallow aquifer wells under existing provisions of the Missouri Well Driller's Law, county ordinances governing residential construction, county well permit restrictions, and public education programs.
Estimated Capital Cost: $2,518,998.
Estimated Annual Operation & Maintenance Costs: not provided.
Net Present O&M Costs: $175,137 (for ten years).
Estimated Present Worth Costs: $ 2,694,125.
Other Costs: $ 2,312 per household for 20 years to replace the treatment units, and extension of service contracts for the treatment units. $17,611 for design phase sampling.
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