One focus of the USGS Toxic Substances Hydrology (Toxics) Program is to investigate the occurrence and fate of agricultural chemicals in the environment from pesticides, fertilizers, veterinary medicines, and other sources. A wide variety of Toxics Program investigations study the fate of agricultural chemicals either directly or indirectly. Toxics Program agricultural chemical investigations focus on:

• Characterizing the processes that affect the dispersal of chemicals in the atmosphere, ground water, and surface water
• Discovering the processes that control the fate of nutrients in the environment
• Identifying persistent pesticide degradation products
• Developing methods to measure these compounds in water samples at environmentally relevant concentrations
• Assessing the impact of hypoxia, eutrophication, and other processes on water bodies receiving drainage from agriculturally dominated watersheds

Results of these investigations are used by government regulators, pesticide manufacturers, farmers, water resource managers, and the public to set sound policy on the use of agricultural chemicals. The information presented on this page cuts across lines drawn by individual investigations and projects so that the information on the fate of agricultural chemicals can be presented in one place.

Investigations and Research Activities

• Pesticide Contamination in Varied Pesticide-Use Settings Investigations
• Animal Feeding Operations as a Source of Antibiotics in the Environment
• Aquaculture as a Source of Antibiotics in the Environment
• Antibiotics in the Spring Flush that Occurs in Midwestern Streams
• Distribution of Pathogenic and Antibiotic-Resistant Bacteria in a Swine Waste Storage Structure
• Herbicides and other Agricultural Chemicals -- Midwest Corn Belt
• Cotton Agriculture -- Southern United States
• Management Systems Evaluation Areas, Upper Midwest (Corn Belt) Completed
• Transport of Herbicides in Streams -- Cedar River, Iowa Completed
• Nonpoint-Source Ground-Water Contamination in Relation to Land Use Completed
• Agricultural Chemicals in Ground Water -- Plains, Georgia Completed
• Fate of Nitrogen During Transport Through Agriculturally Impacted Rivers
• Transport and Transformation of Nutrients in Channels and Floodplains
• The Fate and Transport of Agriculturally derived Nitrogen in the Midwestern United States
• Physical Chemistry of Stable Isotope Fractionation in Hydrologic Processes
• Hypoxia in the Gulf of Mexico and Related USGS Activities

Fact Sheets

• Herbicides in Midwestern Reservoir Outflows, 1992-93, USGS Fact Sheet 134-98
• Herbicides in Ground Water of the Midwest--A Regional Study of Shallow Aquifers, 1991-94, USGS Fact Sheet FS-076-98
• Reconnaissance for Sulfonylurea Herbicides in Waters of the Midwestern USA: An Example of Collaboration Between the Public and Private Sectors, USGS Fact Sheet FS-046-98
• Occurrence of Cotton Pesticides in Surface Water of the Mississippi Embayment, USGS Fact Sheet FS-022-98
• Herbicides in Rainfall Across the Midwestern and Northeastern United States, 1990-91, USGS Fact Sheet FS-181-97
• Agricultural Chemicals in Iowa's Ground Water, 1982-95 -- What are the Trends?, USGS Fact Sheet FS-116-97
• Nitrogen in the Mississippi Basin--Estimating Sources and Predicting Flux to the Gulf of Mexico, USGS Fact Sheet FS-135-00

USGS technicians collecting water samples from a bridge for a reconnaissance of herbicide concentrations in streams
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Incorporating encapsulated herbicide (Atrazine) into the soil as part of an experiment to determine if encapsulating herbicides reduces runoff. The white pipes sticking up out of the ground are lysimeters used to sample water from the unsaturated zone.
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Headlines

• Biosolids, Animal Manure, and Earthworms: Is There a Connection?
• Glyphosate Found in Wastewater Discharged to Streams
• A Decade of Research on the Occurrence of Triazine Herbicides in the Environment Leads to a Unique Summary
• Nitrogen Isotope Study Answers Questions about the Transport of Nutrients in Streams
• Veterinary Medicines in the Environment
• Glyphosate Herbicide Found in Many Midwestern Streams, Antibiotics Not Common
• Measuring New Pesticides and How they Transform in the Environment
• Management Practices a Factor in Herbicide Declines
• Degradates: A Key to Assessing Herbicide Impacts in Streams
• Science of the Total Environment Special Issue on Agricultural Chemicals
• New Report on Science for Hypoxia in Gulf of Mexico
• USGS Info Guides Gulf of Mexico Hypoxic Zone Action Plan
• Hypoxia in the Gulf of Mexico Investigations

An autosampler set up to collect water samples for analysis of pesticides during storm events as part of a reconnaissance of stream waters in peanut production areas in the southeastern United States. The autosampler was located on Black Creek near Blitchton, GA (circa 2003)
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Bibliography

Publications on Agricultural Chemicals (650 Publications)

New Publications

• Understanding the occurrence and transport of current-use pesticides in the San Francisco Estuary watershed: Kuivila, K.M., and Hladik, M.L., 2008, San Francisco Estuary and Watershed Science, v. 6, no. 3, Article 2.

The analysis of pesticides sometimes requires large-volume water samples to detect pesticides that are toxic at low concentrations. This is a view of a pump used to collect samples from the San Joaquin River near Vernalis, CA (circa 2000). The sampling effort was part of a project to study pesticides and other anthropogenic chemicals in the San Francisco Bay/Delta
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Diagram of an Atrazine molecule showing replacement of its chlorine atom with a hydroxyl group. Hydroxyatrazine is a metabolite of Atrazine commonly found in ground water. Atrazine is a herbicide used on corn and sorghum. Atrazine and other herbicides were studied as part of a reconnaissance of herbicide concentrations in streams
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