Glyphosate as an underlying cause of increased dissolved reactive phosphorus loading in the Western Lake Erie basin

Western Lake Erie has been experiencing increasing dissolved reactive phosphorus (DRP) loads since 1995, the causes of which are poorly understood. Changing agricultural practices are certain to have an effect on DRP loads, as the herbicide glyphosate (RoundUp^®) is known to displace phosphate from soil particles. This study links glyphosate to the observed increase in Maumee River DRP loads since 1994 by examining phosphate desorption from Maumee River watershed soil samples in equilibration with glyphosate solutions. Glyphosate's widespread usage contributes to DRP loadings and eutrophication in Western Lake Erie. These findings also suggest that glyphosate contributes to increased DRP loads in freshwater systems worldwide.