Site Name: FARMERS' MUTUAL COOPERATIVE

EPA ID: IAD022193577 EPA Region: 07 Metro Statistical Area:

HWY 60 & PINE ST, HOSPERS, IA 51238

Operable Unit: 01

ROD ID: EPA/ROD/R07-92/059 ROD Date: 09/29/92

Contaminant: VOCs, Other Organics

Keys: Carcinogenic Compounds; Contingent Remedy; Drinking Water Contaminants; Ground Water; Ground Water Monitoring; MCLs; Organics; Pesticides; Plume Management; Safe Drinking Water Act; VOCs

Abstract:

SITE HISTORY/DESCRIPTION: The 6-acre Farmers' Mutual Cooperative site is an active grain storage facility in Hospers, Sioux County, Iowa. Land use in the area is predominantly agricultural. The 643 residents of the City of Hospers obtain their drinking water from municipal water supplies and private wells. From 1908 to the present, the Farmers Mutual Cooperative Company (FMCC) used the site for the purchasing and storing of grain and agricultural chemicals, including pesticides and fertilizers. In addition, grain fumigation had been conducted onsite. In 1984, state investigations detected VOCs and herbicides in the ground water of three shallow city wells adjacent to the FMCC facility. In 1989, the state ordered FMCC to conduct an RI/FS, which showed ground water contamination was limited to the shallow wells and did not impact the deeper aquifer. The City of Hospers uses three deep aquifer wells and installed an additional deep well to meet their water supply needs. Prior actions, including removal of bulk pesticides and further handling from FMCC, have been taken to prevent additional release of contaminants. This ROD addresses ground water contamination as a final remedial action for this site. The primary contaminants of concern affecting the ground water are VOCs, including carbon tetrachloride; and other organics, including pesticides.

PERFORMANCE STANDARDS OR GOALS: Chemical-specific ground water clean-up goals are based on SDWA MCLs and include carbon tetrachloride 0.005 mg/l; chloroform 0.1 mg/l; alachlor 0.002 mg/l; atrazine 0.003 mg/l; cyanazine 10 ug/l; and metolachlor 100 ug/l.

INSTITUTIONAL CONTROLS: Not Provided.

Remedy: SELECTED REMEDIAL ACTION: The selected remedial action for this site includes allowing ground water to naturally attenuate; monitoring ground water to determine the effectiveness of the remedy; and providing for a contingency in the event that use of the impacted aquifer as a water supply is necessary prior to complete restoration. This contingency includes developing and implementing a blending program for the City of Hospers water from the upper and lower aquifers until MCLs have been achieved; testing the upper aquifer prior to its use; treating contaminated ground water for use as drinking water, or containing contaminants to enable use of the impacted aquifer without treatment. The estimated present worth cost for this remedial action ranges from $93,000 to $187,000, depending on the remedy employed. There are no O&M costs associated with this remedial action.