Degradation of Chloroacetanilide Herbicides: The Prevalence of Sulfonic and Oxanilic Acid Metabolites in Iowa Groundwaters and Surface Waters

From Journal of Environmental Science and Technology vol. 32 no. 11, pp. 1738-1740

By 1S.J. Kalkhoff, 1D.W. Kolpin, 2E.M. Thurman, 3I. Ferrer, and 3D. Barcelo

1U.S. Geological Survey, Iowa City, IA 

2U.S. Geological Survey, Lawrence, KS 

3Department of Environmental Chemistry, CID, CSIC, Barcelona, Spain


Water samples were collected from 88 municipal wells throughout Iowa during the summer and were collected monthly at 12 stream sites in eastern Iowa from March to December 1996 to study the occurrence of the sulfonic and oxanilic metabolites of acetochlor, alachlor, and metolachlor. The sulfonic and oxanilic metabolites were present in almost 75% of the groundwater samples and were generally present from 3 to 45 times more frequently than their parent compounds. In groundwater, the median value of the summed concentrations of acetochlor, alachlor, and metolachlor was less than 0.05 mg/L, and the median value of the summed concentrations of the six metabolites was 1.2 mg/L. All surface water samples contained at least one detectable metabolite compound. Individual metabolites were detected from 2 to over 100 times more frequently than the parent compounds. In surface water, the median value of the summed concentrations of the three parent compounds was 0.13 mg/L, and the median value of the summed concentrations of the six metabolites was 6.4 mg/L. These data demonstrate the importance of analyzing both parent compounds and metabolites to more fully understand the environmental fate and transport of herbicides in the hydrologic system.


Limited number of reprints of this report are available upon request from 

Project Chief
Eastern Iowa Basins
U.S. Geological Survey
PO Box 1230
Iowa City, IA 52244
Phone: (319) 358-3611

USGS Water Biology Geology Mapping WRI Pubs Water Related Pubs


U.S. Department of the Interior, U.S. Geological Survey
Last updated: Monday, October 07, 2002 12:16:08 PM Monday, 07-Oct-2002 13:53:55 EDT
Privacy Statement || Disclaimer || Accessibility
FirstGov, 'Your First Click to the U. S. Government'