Pesticides play an important role in agriculture. They have increased farm production, and they have enabled farmers to manage more acres with less labor. If pesticides are not handled carefully around the farmstead, they can seep through the ground after a leak or spill, or they can enter a well directly during mixing and loading. Taking voluntary action to prevent pesticide contamination of groundwater will help assure their continued availability for responsible use by farmers.
Pesticides work by interfering with the life processes of plants and insects. Pesticides are also toxic to people. If pesticides enter a water supply in large quantities -- as can happen with spills or backsiphonage accidents -- acute health effects (toxic effects apparent after only a short period of exposure) can range from moderate to severe, depending on the toxicity of the pesticide and the amount of exposure. Contaminated groundwater used for drinking water supplies may result in chronic exposure (prolonged or repeated exposure to low doses of toxic substances), which may be hazardous to people and livestock.
When found in water supplies, pesticides normally are not present in high-enough concentrations to cause acute health effects, which can include chemical burns, nausea and convulsions. Instead, they typically occur in trace levels, and the concern is primarily for their potential for causing chronic health problems from prolonged exposure.
Your drinking water is least likely to be contaminated if you follow appropriate management procedures or dispose of wastes in any location that is off the farm site. However, proper offsite disposal practices are essential to avoid risking contamination that could affect the water supplies and health of others.
The goal of Farm*A*Syst is to help you protect the groundwater that supplies your drinking water.
How will this worksheet help me protect my drinking water?
- It will take you step by step through your pesticide handling, storage and disposal practices.
- It will rank your activities according to how they might affect the groundwater that provides your drinking water supplies.
- It will provide you with easy-to-understand rankings that will help you analyze the risk level of your pesticide handling, storage and disposal practices.
- It will help you determine which of your practices are reasonably safe and effective, and which practices might require modification to better protect your drinking water.
Air gap: An air space (open space) between the hose or faucet and water level, representing one way to prevent backflow of liquids into a well or water supply.
Anti-backflow (anti-backsiphoning) device: A check valve or other mechanical device to prevent the unwanted reverse flow of liquids back down a water supply pipe into a well.
Backflow: The unwanted reverse flow of liquids in a piping system.
Backflow prevention device: (See anti-backflow device.)
Backsiphonage: Backflow caused by formation of a vacuum in a water supply pipe.
Closed handling system: A system for transferring pesticides or fertilizers directly from storage container to applicator equipment (through a hose, for example), so that humans and the environment are never inadvertently exposed to the chemicals.
Cross-connection: A link or channel between pipes, wells, fixtures or tanks carrying contaminated water and those carrying potable (safe for drinking) water. Contaminated water, if at higher pressure, enters the potable water system.
Micrograms per liter: The weight of a substance measured in micrograms contained in one liter. It is equivalent to 1 part per billion in water measure.
Milligrams per liter (mg/l): The weight of a substance measured in milligrams contained in one liter. It is equivalent to 1 part per million in water measure.
Parts per billion (ppb): A measurement of concentration of one unit of material dispersed in one billion units of another.
Parts per million (ppm): A measurement of concentration of one unit of material dispersed in one million units of another.
Rinsate: Rinse water from pesticide or fertilizer tank cleaning.
Secondary containment: Impermeable floor and walls around a chemical storage area that minimize the amount of chemical seeping into the ground from a spill or leak.
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The Farm*A*Syst Program is a cooperative program funded nationally by: USDA Cooperative State Research Education Service (CSREES), USDA Natural Resources Conservation Service (NRCS), and the US Environmental Protection Agency. This worksheet has been produced by the National Farm*A*Syst Office located at B142 Steenbock Library, 550 Babcock Drive, Madison, WI 53706-1293, Phone: (608) 262-0024. This worksheet is based on the original Wisconsin Farmstead Assessment Program. The principal author for this worksheet was Susan Jones, US EPA Region V, Water Division, and University of Wisconsin-Extension, Cooperative Extension. |
July 24, 1998
Dennis Hoffman, Project Leader
Steve Dagitz, Webmaster