STUDY NUMBER ; 4.4 



ORGANIZATION : Montana Department of Health and Environmental 

 Sciences (MDHES) - Solid and Hazardous Waste Bureau 



TITLE OF STUDY ; Milltown Superfund Site Studies 



CONTACT ( S ) ; Charles Coleman - Solid and Hazardous Waste Bureau 



- Montana Department of Health and Environmental 

 Sciences - 444-2821 



Jim Knoy - Environmental Protection Agency Montana 

 Office - 449-5414 



Duane Robertson - Solid and Hazardous Waste Bureau 

 Chief - 444-2821 



OBJECTIVE; Evaluate alternatives (and select a preferred alterna- 

 tive) to rectify impacts to human health, the aquatic environment 

 and groundwater which have resulted from contamination of res- 

 ervoir sediments by arsenic and heavy metals. 



DURATION ; 1983 - 1987 



CURRENT STATUS ; In May, 1981, four community wells in Milltown 



were tested by health officials and found to be contaminated 



by arsenic. Subsequent studies by the University of Montana 



suggested that the contamination source was heavy metal deposits 



within the reservoir's sediments. The reservoir was designated 



as a Superfund site and a Remedial Investigation (RI) was begun 



in July, 1983 to confirm the source and extent of groundwater 



contamination. The RI was completed in July, 1984; "Arsenic 



Source and Water Supply Remedial Action Study, Milltown Reser- 

 II 



Concurrent with the RI, a focused Feasibility Study (FS) 

 was conducted to determine the most efficient way to provide 

 safe water for Milltown residents. Construction of a new central 

 water system for Milltown was begun in the fall of 1984 and com- 

 pleted in June, 1985. 



With the immediate, pressing problem of the Milltown water 

 supply corrected, a more extensive Feasibility Study was initiated 

 to address ways to: 



o minimize down gradient/down stream release of contami- 

 nants originating at Milltown Reservoir, and 



o minimize ingestion of contaminants originating at the 

 Milltown site. 



The FS, which is being conducted by Harding, Lawson Associ- 

 ates, is currently in progress. Additional groundwater monitoring 



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