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are removed or treated the cleaner sediments could be 

 returned to the site. Sediment removal with specialized 

 equipment to minimize resuspension of toxic sediments has 

 already been developed, and could be incorporated into this 

 new technology when full-scale remediation is implemented. 

 This would prevent the resuspension of sediments that is 

 associated with the typical means of dredging. 



The first strategy mentioned in the report would involve 

 testing treated particles and mesh which would bind the 

 contaminants. These binding agents and their carrier could 

 be left in place or could be removed after they have become 

 a toxic sync. The use of a polymer mesh may be useful in 

 stabilizing sediments in areas which would otherwise be 

 scoured by river currents. 



Another approach which might prevent biotic uptake would be 

 to inject binding agents into the deeper sediments. In many 

 areas these underlying sediments have higher levels of 

 contaminants then the overlying sediments of recent origin. 

 The data on mercury levels of fish from these areas show 

 that active biotic uptake is still occurring. I am mailing 

 a copy of our October 1992 report. Mercury Concentrations in 

 Fish. Plankton, and Water from the St. Louis River Watershed 

 Including the Reservoir Lakes . This report clearly shows 

 the increased levels of mercury in fish from areas where 

 high levels of mercury in the sediments remain or other 

 factors are contributing to increased mercury methylization. 



The original cost estimates for the study could be scaled 

 down, and we would request that recommendations on total or 

 yearly project grant levels be provided to us. If you have 

 any additional questions regarding this proposal please 

 contact me at (218-879-4593), or John Sorenson at (218-525- 

 7423) . 



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