Pesticide Monitoring

The Pesticide Monitoring Program collects water samples from drinking water sources near agricultural lands to evaluate whether or not agricultural chemicals are reaching Vermont groundwater. The types of water supplies sampled by the Monitoring Program include: drilled, driven point or dug wells and springs, ponds or lakes used as drinking water supplies for human or livestock consumption and irrigation. The Monitoring Program tests wells in agricultural areas to help farmers learn about practices that prevent pesticide leaching and conserve the nutrients in fertilizers and manure in the soil. The water quality information provided by this program also helps farmers decide if tillage practices and crop rotations are working to reduce the amounts of nutrients and pesticides lost to groundwater or surface run-off. Sharing this information with farmers, agricultural dealers, landowners, conservation organizations and other departments of state government helps to improve agricultural practices, protect groundwater, raise public awareness and provide for clean drinking water and a healthy environment in Vermont.

The Pesticide Monitoring Program started collecting samples in 1986. As of 2002, the program has tested 1215 wells statewide. The sampling and laboratory analyses conducted by the Monitoring Program are paid for by registration fees collected from companies that sell pesticides and fertilizers in Vermont. All sample collection work is done by Agriculture Department and Conservation District field staff. The sample analysis work is done by the Department of Agriculture Laboratory in Waterbury.

The major focus of the Pesticide Monitoring Program is on testing groundwater for corn herbicides because, with the exception of chemicals used for cooling towers and water treatment, corn herbicides are used more than any other group of pesticides. In an average year, 76% of all pesticides used outdoors in Vermont are herbicides applied to land used for growing silage or sweet corn. The Corn Herbicide Project also tests for nitrate which is associated with fertilizers, manure or septic systems. Excess application rates of manure and fertilizer or faulty septic systems can cause nitrate to reach groundwater by leaching downward through the soil.

In addition to sampling farm wells, the Monitoring Program has several other projects that sample surface and groundwater near other types of land use where pesticides and fertilizers are used. These projects include farms that are inspected for Accepted Agricultural Practices (AAPs), Large Farm Permits (LFOs) and Best Management Practices (BMP) Cost Share Grants. The Monitoring Program also tests wells and streams on golf courses and along highways, electric power lines and railroads that receive right-of-way permits from the Department of Agriculture and the Pesticide Advisory Council.

The Department of Agriculture is mapping the location of all farms and all the wells sampled by the Monitoring Program. This project will create a statewide map using watershed boundaries, soils, geology, well data and drinking water quality to determine which parts of the state may be vulnerable to groundwater or surface water contamination and which regions are being protected by good management practices.

Drinking water standards are set by the Federal Environmental Protection Agency (EPA) and the Vermont Department of Health. Drinking water standards set an allowable limit of a substance in water. This standard is based on an expected lifetime exposure from drinking two (2) quarts of water each day for seventy (70) years.

The table below provides the trade names, common names and drinking water standards of the chemicals tested for by the Monitoring Program. These compounds were selected for testing because they are the herbicides and fungicides most commonly used in Vermont.

The Department of Agriculture=s Monitoring Program has found that low levels of nitrate in groundwater are common in agricultural areas. For all wells sampled since 1998, 46% of the wells tested showed no detectable levels of nitrate-N and 54% tested positive. Thirty-one (31%) were less than 5 ppm and 12% exceeded the standard of 10 ppm. If your drinking water contains nitrate-N at a level between 5 and 10 ppm, the water may be consumed but the source of nitrate should be identified and the problem corrected. If the nitrate-N level exceeds 10 ppm, which is the state and federal drinking water standard, the Departments of Agriculture and Health recommend finding an alternative source of drinking water until the problem is corrected.

February, 2003

Based on the current sampling results, the number of wells for farms or their neighbors in Vermont with detectable levels of herbicide is low. Only one in twenty-five (4%) of the wells tested showed traces of herbicide. Of all the wells retested since 1995, there are no wells above the drinking water standards for herbicides.

Participation in the Monitoring Program is completely voluntary. Every person whose well is tested for herbicides and nitrate receives a letter with a written copy of the results from the Department of Agriculture. If test results indicate that drinking water has detectable levels of herbicide or high levels of nitrate-N, the Department of Agriculture recommends resampling the well to evaluate the success of efforts to clean up the water supply.

Well owners can get help in evaluating and correcting the sources of nitrate or herbicide in their drinking water from one of several sources.

The Vermont Department of Agriculture works with well owners on water sampling, well construction, manure management, fertilizer testing, worker protection rules and pesticide use recommendations. The Department also issues permits for Large Farm Operations and cost share grants for non-point source control practices (BMPs).

The University of Vermont Extension System works with landowners on livestock production and cropping practices, cover crops, pesticide and manure use recommendations, nutrient management and manure and soil testing.

The USDA Natural Resources Conservation Service and the local Natural Resource Conservation Districts work with landowners on manure storage systems, control of barnyard and milkhouse wastes, preventing soil erosion, stream bank restoration and watershed conservation practices. The Conservation Districts (NRCD) are also responsible for education and technical assistance related to Accepted Agricultural Practices (AAPs) and offer farm site assessments for pollution prevention and the evaluation of risks to drinking water through the voluntary Farm*A*Syst Program.

For further information about the Monitoring Program, Vermont=s agricultural water quality programs or other agricultural practices, please call one of the participating agencies listed below.

The Geographic Information System Project has set a priority on using the capability of the global positioning satellite system (GPS) to do GIS mapping. The GPS technology is being used to collect field data and map the locations of all farms or wells sampled by the Monitoring Program and the Agricultural Non-Point Source Program. Combining these projects for water quality sampling and nutrient management practices allows the department to coordinate watershed priorities for Best Management Practices cost share funding, Accepted Agricultural Practices investigation, and drinking water protection areas. During the 1995-1996 biennium, the department mapped 471 farm sites and/or wells using GPS technology.