Jump to main content.


Local Navigation


Record of Decision System (RODS)

LEHILLIER/MANKATO

Abstract

Site Name:  LEHILLIER/MANKATO
Address:  W. SIBLEY PK & LEHILLIER/SOUTH BEND TWP 
City & State:  LEHILLIER  MN  56001
County:  BLUE EARTH
 
EPA ID:  MND980792469
EPA Region:  05
 
NPL Status:  Currently on the Final NPL
 
ROD Type:  Record of Decision
ROD ID:  EPA/ROD/R05-85/024
ROD Date:  09/27/1985
Operable Unit(s):  01
 
Media:  GROUNDWATER SOIL
 
Contaminant:  TRICHLOROETHYLENE (TCE)
 
Abstract:  THE LEHILLIER/MANKATO SITE IS LOCATED IN SOUTH-CENTRAL MINNESOTA APPROXIMATELY 80 MILES SOUTHWEST OF MINNEAPOLIS-ST. PAUL, ADJACENT TO THE CITY OF MANKATO. THE LEHILLIER AREA CONTAINED NUMEROUS NATURAL AND MANMADE DEPRESSIONS RESULTING FROM CHANGES IN THE CHANNELS OF THE MINNESOTA AND BLUE EARTH RIVERS, AND FROM EXCAVATION OF SAND AND GRAVEL. BETWEEN 1925 AND 1960, THESE DEPRESSIONS WERE FILLED WITH MISCELLANEOUS RUBBISH. NO RECORDS OF THE DUMPING ACTIVITIES OR TYPES OF WASTE MATERIALS WERE KEPT. IN THE FALL OF 1981, THE MINNESOTA POLLUTION CONTROL AGENCY (MCPA) RECEIVED INFORMATION ALLEGING THAT HAZARDOUS WASTES HAD BEEN DISPOSED OF AT SEVERAL DUMPS OR FILL AREAS IN LEHILLIER. A FOLLOWUP INVESTIGATION CONFIRMED THE EXISTENCE OF THESE DISPOSAL AREAS AND CONTAMINATION OF THE SHALLOW SAND AND GRAVEL AQUIFER WITH VOLATILE HALOGENATED HYDROCARBONS, PRIMARILY TRICHLOROETHYLENE (TCE).

THE SELECTED REMEDIAL ACTION INCLUDES; EXTRACTION, WITH PARTIAL TREATMENT BY AIR STRIPPING, OF THE CONTAMINATED GROUND WATER PLUME THROUGH ADAPTATION OF EIGHT EXISTING U.S. ARMY CORPS OF ENGINEERS (COE) GROUND WATER AND FLOOD CONTROL WELLS AND CONSTRUCTION OF TWO NEW EXTRACTION WELLS; EXTENSION OF THE LEHILLIER COMMUNITY WATER SYSTEM TO AFFECTED RESIDENTS AND BUSINESSES NOT CURRENTLY SERVICED; AND PROPER ABANDONMENT, IN ACCORDANCE WITH STATE WELL CODES, OF INDIVIDUAL WELLS FORMERLY USED AS DRINKING WATER SUPPLIES. THIS ACTION WILL MANAGE CONTAMINANT MIGRATION UNTIL CONTAMINANT LEVELS REACH DRINKING WATER QUALITY. TOTAL CAPITAL COST FOR THE SELECTED REMEDIAL ACTION IS ESTIMATED TO BE $800,000 WITH FIRST YEAR OPERATION AND MAINTENANCE COSTS OF $70,000. THE STATE OF MINNESOTA WILL CONTINUE O&M FOR THE REMAINING DURATION WHICH SHOULD NOT EXCEED 9 YEARS.
 
Remedy:  - A SYSTEM OF TEN EXTRACTION WELLS WITH PARTIAL TREATMENT BY AIR STRIPPING WHICH AGGRESSIVELY PUMPS AND TREATS CONTAMINATED GROUNDWATER OVER A TEN YEAR PERIOD OR UNTIL ACCEPTABLE LEVELS IN GROUNDWATER ARE REACHED. THIS SYSTEM IS NECESSARY TO EFFECTIVELY CONTROL MIGRATION OF CONTAMINANTS AND PROTECT CURRENT AND FUTURE DRINKING WATER SUPPLIES FOR THE CITY OF MANKATO (POP. 29,000).
- EXTENSION OF THE LEHILLIER COMMUNITY WATER SYSTEM TO AFFECTED RESIDENTS AND BUSINESSES NOT CURRENTLY SERVICED.
- PROPER ABANDONMENT IN ACCORDANCE WITH STATE WELL CODES OF INDIVIDUAL WELLS FORMERLY USED AS DRINKING WATER SUPPLIES.
- THE SELECTED ALTERNATIVE HAS TOTAL CAPITAL COST OF $800,000 AND FIRST YEAR OPERATION AND MAINTENANCE COST OF $70,000. THE TOTAL 10 YEAR PRESENT WORTH IS $1.3 MILLION.
 
Text:  View full-text ROD [ 30K ]
To download a full-text ROD, right click on the above link and select Save Link As. A full-text ROD is in PDF format. Please note that download time may be extended given the size of the full-text document. File size is noted in kilobytes (K) or megabytes (M) next to the download link.
About Adobe Portable Document Format
 
Return to Search Results   

OSWER Home | Superfund Home


Jump to main content.