Nutrients (Ammonia-nitrogen, Nitrate-nitrogen, Nitrite-nitrogen, 

 and Total Phosphorus) . An extensive literature search yielded very 

 little information on pre-construction nutrient levels in the upper 

 Mississippi River. Clarke (1908, in Galtsoff, 1921: 371) reported 

 nitrate-nitrogen concentrations of 0.85 ppm at Minneapolis, Minnesota 

 (Mississippi River mile 850) and 0.10 ppm at Memphis, Tennessee in 

 1906-1907. In 1921, McHargue and Peter (1921, in Platner, 1946: 5) 

 found that nitrate-nitrogen was absent in samples at Minneapolis, but 

 occurred at Baton Rouge, Louisiana. Ammonia-nitrogen apparently 

 occurred only in the Baton Rouge samples (McHargue and Peter, 1921, 

 in Platner, 1946: 5). 



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