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E-M:/ More on Manure

In a previous posting, factory farm supporters pointed to human waste when trying to minimize and justify the impacts of industrial manure spreading.  While most of us can see through this flawed argument, I wanted to see what the relative contribution of nutrients to surface waters came from each sector.  Here's what I found:
US Geological Survey

Water Quality in the Western Lake Michigan Drainages, Wisconsin and Michigan, 1992-95


Fertilizers and Livestock Wastes Increase Nutrients in Streams and Ground Water

Pie Chart of Phosphorus Inputs
More than 96 percent of the total anthropogenic phosphorus input to the study area is in the form of commercial fertilizers and livestock manures. Point sources such as sewage-treatment plants contribute only about 1.2 percent of the total input (Robertson, 1996a).