268 



Mercury in Water. Plankton, and Sediment. Mercury levels in water showed some sites were 

 higher than average conccnirations, possibly indicatitig watershed inputs. Mercury 

 concentrations in plankton were highest at site 1710 (Scanlon Dam), the same site where the 

 highest mercury levels in fish were observed. The mouth of the Midway River and three sites 

 above the town of Cloquet showed the highest mercury contamination in sediment. More 

 sediment analyses from the upstream areas of this study and beyond are needed to better 

 identify potential mercury sources. 



References 



Bodaly, R.A., R.E. Hecky, and R.J.P. Fudge. 1984. Increases in Fish Mercury Levels in Lakes 

 Hooded by the Churchill River Diversion. Northern Manitoba. Canadian Journal of 

 Fisheries and Aquatic Sciences. 41(4):682-691. 



Glass. G.E.. Sorensen. J. A.. Schmidt. K. W., and Rapp. G. R.. Jr. 1990. New Source 

 Identification of Mercury Contamination in the Great Lakes. Environ. Sci. &. Technol. 

 24(7):1059-1069. 



Olson, G.F.. Mount. D.I., and Snarski, V. M. 1975. Mercury Residues in Fathead Minnows. 

 Pimephales promelas Rafinesque. Chronically Exposed to Methylmercury in Water. Bullet. 

 Environ. Contam. Tax. 14(2);129-134. 



MDH. 1992. Minnesota Fish Consumption Advisory. Minnesota Depanment of Health, 

 Minneapolis MN. 



StLR RAP. 1992. The St. Louis River System Remedial Action Flan - Stage One Report. 

 Minnesota Pollution Control Agency. St. Paul MN. 



Sorensen. J.A.. G.E. Glass. K.W. Schmidt, and G.R. Rapp. Jr. 1992a. Mercury Concentrations 

 in Fish from the St. Louis River near the Fond du Lac Indian Reservation. Report to Fond 

 du Lac Indian Reservation. Cloquet. MN. 



Sorensen. J.A.. Glass. G. E.. Schmidt, K. W.. Ruber. J. K.. and Rapp. G. R.. Jr.: 1990. Airborne 

 Mercury Deposition and Watershed Characteristics in Relation to Mercury Concentrations 

 in Water, Sediments. Plankton, and Fish of Eighty Northern Minnesota Lakes. Environ. Sci. 

 & Technol. 24(1 1):1716-1727. 



USEPA 1983. Mercury Method 245.1 Revised 3/83. EPA-600/4-79-020. 



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