Measuring Pesticides and How They Transform in the Environment

New and innovative pesticides are being developed and are applied in the environment every year. In many cases, methods to assess the fate of these new pesticides and their degradates in the environment are not available. The Toxic Substances Hydrology (Toxics) Program develops methods to measure a variety of pesticides and their degradates, and assesses their environmental transport. Degradates are the product of environmental transformation of the parent pesticide and can have similar properties. (More information on the significance of degradates in streams and ground water is available.) The methods are effective at low but environmentally significant levels, enabling determination of the potential for, and circumstances of, harmful effects. This information is used for pesticide registration, resource management, and manufacturing decisions. For example:

• The U.S. Geological Survey (USGS) has developed two new water-quality analytical methods for the determination of chloroacetanilide herbicide degradates in water. These methods use solid-phase extraction and high performance liquid chromatography - diode array detection (HPAA) and high performance liquid chromatography - mass spectrometry (LCAA). Both methods measure the concentration of 10 acetanilides herbicide degradates in samples of filtered water. The reporting limits for the HPAA method are 0.2 micrograms per liter (ug/L), while reporting limits for the LCAA method are 0.05 ug/L.

  The following degradates are measured:

  • Acetochlor ethane sulfonic acid
  • Acetochlor oxanilic acid
  • Alachlor ethane sulfonic acid
  • Alachlor oxanilic acid
  • Dimethenamid ethane sulfonic acid
  • Dimethenamid oxanilic acid
  • Flufenacet ethane sulfonic acid
  • Flufenacet oxanilic acid
  • Metolachlor ethane sulfonic acid
  • Metolachlor oxanilic acid

  These are the degradates of the widely used herbicides acetochlor, alachlor, and metolachlor, which are applied on a variety of crops. These methods are being used by the USGS's National Water-Quality Assessment (NAWQA) Program and other water-quality investigation projects

• The Toxics Program has been developing new methods to measure the concentration of cotton herbicides and insecticides in water samples. For example, USGS researchers have developed a low-cost method for the analysis of the cotton herbicide fluometuron that uses a novel approach to immunoassay measurement methods. The new method reduced the cost of analysis from $200 per sample for traditional analysis to $20 per sample--a cost savings of 90%. These new methods have allowed the USGS and the U.S. Environmental Protection Agency (USEPA) to study the impact of cotton herbicides and insecticides on the environment. The USEPA is using this data in its registration process for pesticides.

• A Cooperative Research and Development Agreement (CRADA) was developed with the DuPont Chemical Company to investigate the occurrence of selected sulfonylurea (SU), sulfonamide (SA), and imidazolinone (IM) herbicides in waters of the Midwestern United States. Researchers from the Toxics Program, the USGS National Water Quality Laboratory, and chemists from DuPont developed new methods for measuring the concentration of 16 SU, SA, and IM compounds in water. These herbicides are very toxic to plants and are applied to fields at very low rates. As part of the CRADA, a reconnaissance for the occurrence of the these low-use herbicides in streams was conducted by the USGS. A fact sheet on the project is available.

• Some of the most widely used herbicides in the Nation are acetochlor, alachlor, atrazine, cyanazine, and metolachlor. The Toxics Program has developed sensitive methods to measure the concentration of these herbicides and their degradates in water samples at concentrations that are environmentally significant. The method uses solid-phase extraction to remove pesticides from a water sample and then employs gas chromatography/mass spectrometry. The detection levels in many traditional methods are too high for studies on the fate of these pesticides in the environment. For some of these pesticides, but more importantly for the pesticides' degradates, methods to measure their concentration in water were not available. These methods are now being used by the U.S. Geological Survey's Toxics Program and NAWQA to assess the fate of these pesticides in the environment.

More Information on Pesticides

• Agricultural Chemicals in the Upper Midwest (Corn Belt) Investigation
• The Fate of Cotton Pesticides in the Southern United States Investigation
• Topical Information on Agricultural Chemicals
• Glyphosate Found in Wastewater Discharged to Streams
• Glyphosate Herbicide Found in Many Midwestern Streams, Antibiotics Not Common
• A Decade of Research on the Occurrence of Triazine Herbicides in the Environment Leads to a Unique Summary
• Tracking Atrazine and a Breakdown Product (deethylatrazine) through a Drinking-Water Reservoir
• Management Practices a Factor in Herbicide Declines
• Degradates: A Key to Assessing Herbicide Impacts in Streams
• Where are the Pesticides?
• Science of the Total Environment Special Issue on Agricultural Chemicals

References

Battaglin, W.A., Furlong, E.T., Burkhardt, M.R., and Peter, C.J., 2000, Occurrence of sulfonylurea, sulfonamide, imidazolinone, and other herbicides in rivers, reservoirs and ground water in the Midwestern United States, 1998: The Science of the Total Environment, v. 248, no. 2-3, p. 123-133.

Furlong, E.T., Burkhardt, M.R., Gates, P.M., Werner, S.L., and Battaglin, W.A., 2000, Routine determination of sulfonylurea, imidazolinone, and sulfonamide herbicides at nanogram-per-liter concentrations by solid-phase extraction and liquid chromatography/mass spectrometry: The Science of the Total Environment, v. 248, no. 2-3, p. 135-146.

Battaglin, W.A., Furlong, E.T., Burkhardt, M.R., and Peter, C.J., 1999, Occurrence of sulfonylurea, imidazolinone, and other herbicides in Midwestern rivers, reservoirs, and ground water, 1998, in Morganwalp, D.W., and Buxton, H.T., eds., U.S. Geological Survey Toxic Substances Hydrology Program--Proceedings of the Technical Meeting, Charleston, South Carolina, March 8-12, 1999--Volume 2 of 3--Contamination of Hydrologic Systems and Related Ecosystems: U.S. Geological Survey Water-Resources Investigations Report 99-4018B, p. 215-226.

Battaglin, W.A., Furlong, E.T., and Burkhardt, M.R. 2001, Concentration of selected sulfonylurea, sulfonamide, and imidazolinone herbicides, other pesticides, and nutrients in 71 streams, 5 reservoir outflows, and 25 wells in the midwestern United States, 1998: U.S. Geological Survey Water-Resources Investigations Report 00-4225, 123 p.

Battaglin, W.A., Furlong, E.T., and Peter, C.J., 1998, A reconnaissance for sulfonylurea herbicides in waters of the Midwestern USA--An example of collaboration between the public and private sectors: U.S. Geological Survey Fact Sheet FS-046-98, 4 p.

Bastian, K.C., Thurman, E.M., and Rebich, R.A., 1998, Comparison of enzyme-linked immunoassay with gas chromatography/mass spectrometry for analysis of the cotton herbicide fluometuron, in 28th Mississippi Water Resources Conference, Raymond, Mississippi, April 7-8, 1998: Starkville, Mississippi, Mississippi State University, p. 45-55.

Coupe, R.H., Thurman, E.M., and Zimmerman, L.R., 1998, Relation of usage to the occurrence of cotton and rice herbicides in three streams of the Mississippi Delta: Environmental Science and Technology, v. 32, no. 23, p. 3673-3680.

E.A. Lee, J.L. Kish, L.R. Zimmerman, and E.M. Thurman, 2001, Methods of analysis by the U.S. Geological Survey Organic Geochemistry Research Group--Update and additions to the determination of chloroacetanilide herbicide degradation compounds in water using high-performance liquid chromatography/mass spectrometry: U.S. Geological Survey, Open-File Report 01-10.

Furlong, ET, Burkhardt, M.R., Gates, P.M., Werner, S.L., and Battaglin, WA, 1999, Routine determination of sulfonylurea, imidazolinone, and sulfonamide herbicides at nanogram-per-liter concentrations by solid-phase extraction and liquid chromatography/mass spectrometry, in Morganwalp, D.W., and Buxton, H.T., eds., U.S. Geological Survey Toxic Substances Hydrology Program--Proceedings of the Technical Meeting, Charleston, South Carolina, March 8-12, 1999--Volume 2 of 3--Contamination of Hydrologic Systems and Related Ecosystems: U.S. Geological Survey Water-Resources Investigations Report 99-4018B, p. 275-288.

Steinheimer, T.R., Pfeiffer, R.L., Scoggin, K.D., and Battaglin, W.A., 2000, Reconnaissance survey of sulfonamide, sulfonylurea and imidazolinone herbicides in surface streams and groundwater of the Midwestern United States, in Steinheimer, T.R., Ross, L.J., and Spittler, T.D., eds., Agrochemical Fate and Movement--Perspective and Scale of Study: American Chemical Society Symposium series 751, p. 248-271.

Thurman, E.M., Zimmerman, L.R., Scribner, E.A., and Coupe, R.H., Jr.. 1998, Occurrence of cotton pesticides in surface water of the Mississippi Embayment: U.S. Geological Survey Fact Sheet FS-022-98, 4 p.

Zimmerman, L.R. and Thurman, E.M., 1999, Method of analysis by the U.S. Geological Survey Organic Geochemistry Research Group--Determination of triazine and chloroacetanilide herbicides in water by solid-phase extraction and capillary-column gas chromatography/mass spectrometry with selected-ion monitoring: U.S. Geological Survey Open-File Report 98-634, 21 p.

Zimmerman, L.R., Hostetler, K.A., and Thurman, E.M., 2000, Methods of Analysis by the U.S. Geological Survey Organic Geochemistry Research Group - Determination of Chloroacetanilide Herbicide degradates in Water Using High-Performance Liquid Chromatography-Diode Array Detection and High-Performance Liquid Chromatography/Mass Spectrometry: U.S. Geological Survey Open File Report 00-182.