B.L. Harris, D.W. Hoffman and F.J. Mazac, Jr.

1. Do you store pesticides on your land?
2. Do you use or store any agricultural chemicals near a water well?
3. Are chemicals stored on a permeable surface such as wood, gravel or soil, or are chemicals stored on an impermeable surface with no curb?
4. Do you have any chemical containers that are rusted, damaged or leaking?
5. Are chemicals stored in an area where containers could become damaged or where a chemical spill could occur?
6. Are chemicals stored in a location that is unlocked and open to vandalism or to children?
7. Do you fill the sprayer tank directly from a water well?
8. Do you fill a sprayer tank with a hose that does not have a check valve, or put the hose in the tank so that it is below the liquid line during filling?
9. Do you leave the sprayer tank unattended when filling?
10. Do you mix or load chemicals upslope or within 150 feet of a water well?
11. Do you have a concrete pad with a curb to contain spills during the mixing or loading of chemicals?
12. Do you wash the sprayer tank out and dump the rinsate on your land less than 150 feet from a water well?
13. Do you apply pesticides without reading the label first?
14. Has it been longer than 5 years since you attended a pesticide applicator training?

If these questions create doubt about the safety of your management practices, this publication will provide helpful information.

Pesticide Handling Overview

Pesticides play an important role in agriculture. They have increased farm production and enabled farmers to manage more acres with less labor. Taking voluntary action to prevent pesticide contamination of ground water will help ensure that pesticides remain available for responsible use.

Pesticides work by interfering with the life processes of plants and insects. Some pesticides are also toxic to humans. If a pesticide enters a water supply in large quantities, which could happen with spills or back-siphonage accidents, acute health effects (toxic effects apparent after only a short period of exposure) could occur, depending on the toxicity of the pesticide. Contaminated ground water used for drinking water supplies may cause chronic exposure (prolonged or repeated exposure to low doses of toxic substances). Chronic exposure may be hazardous to humans and livestock.

Normally pesticides are not found in water supplies in high enough concentrations to cause acute health effects, which can include chemical burns, nausea and convulsions. Instead, pesticides usually occur in trace amounts, and the concern is for the chronic health problems that may result from prolonged exposure.

Proper pesticide management on your property is an important step toward preventing ground water contamination. This guide will provide information about the following areas:

1. Pesticide storage
2. Mixing and loading practices
3. Spill clean up
4. Container disposal
5. Other management practices
6. Evaluation table

Pesticide Storage

If stored in a secure, properly constructed location, pesticides pose little danger to ground water. Common sense suggests keeping pesticides out of the way of activities that might knock over a jug or rip open a bag. Short-term storage (during a season) poses a lower risk than year-round storage, but storage for any length of time can be a risk to ground water.

Secondary containment includes an impermeable (waterproof) floor and walls around the storage area. This will minimize the amount of pesticide seeping into the ground if a bulk liquid pesticide storage tank leaks.

If a spill does occur, an impermeable concrete floor should prevent chemical seepage into the ground. Putting a curb around a concrete floor also will prevent chemicals from spreading to other areas.

A mixing or loading pad provides secondary containment during the transfer of pesticides to spraying equipment or nurse tanks.

Building a New Storage Facility

Building a new facility just for pesticide storage may be expensive, but it is usually easier than trying to modify areas meant for other purposes. When building a new facility, keep in mind a few principles of safe pesticide storage.

• Locate the building downslope and at least 100 feet away from your water well. The distance from the well should be greater if the site has sandy soils or fractured bed-rock near the soil surface. The risk of pesticides contaminating ground water is influenced by properties of both the pesticide and the soil on which it is spilled or applied.
• Drain surface water to a confined area because, in the event of a fire, contaminated surface water can be collected more safely.
• Locate the mixing and loading area close to your storage facility in order to minimize the distance that chemicals are carried.
• Provide a well-drained building foundation or secondary containment floor that is high above the water table. The finished soil grade should be 3 inches below the floor and sloped to provide surface drainage away from the building. The subsoil should have a low permeability.
• Keep large drums or bags on pallets and off the floor. Shelves for smaller containers should have lips to keep the containers from sliding off. Steel shelves are easier to clean than wood if a spill occurs. Store dry products above liquids to prevent wetting from spills.
• Provide a containment area large enough to confine 125 percent of the contents of the largest bulk container, plus the displaced volume of any other storage tanks in the area.
• Keep the storage area or building locked for security. Preventing unauthorized use of pesticides reduces the chance of accidental spills or theft. Post signs or labels to identify the area as a pesticide storage area. Labels on the outside of the building will give firefighters information about pesticides if they must respond to a fire or a spill. Also, it is a good idea to maintain, in a separate location, a list of the chemicals and amounts stored.
• Provide adequate road access for deliveries and emergency equipment.
• Keep pesticides separate to prevent cross-contamination. Herbicides, insecticides and fungicides should be kept on separate shelves or in separate areas.

For information on other factors to consider in the design of a storage facility, such as ventilation, water access, temperature control and worker safety, contact your county Extension office or the Texas A&M University Department of Agricultural Engineering.

Modifying an Existing Storage Facility

Remodeling an existing facility to serve as pesticide storage may be less expensive than building a new facility, but remodeling can be complicated. When existing buildings must accommodate other activities, also using them to store pesticides could compromise the safety of people and the environment. Storing chemicals in a separate facility reduces the risk associated with fire or accidental spills. Never store pesticides inside a wellhouse or in a facility containing an abandoned well.

Even if you decide to improve your current storage building, applying the above principles can be expensive. Compared to the cost of a major accident or a lawsuit, however, storage improvements are a bargain. Also, note that the last five items listed in the section above are important points to remember for existing storage facilities.

The least expensive alternative you may have is to reduce the amounts and types of pesticides stored. If that is not practical, consider how stored pesticides can be protected. Sound containers are the first defense against a spill or leak.

When modifying a structure, it is important to note that the building should have a solid floor. If liquid pesticides are stored the building also should have a curb. The modified structure should be large enough to hold 125 percent of the contents of the largest full container, plus the displaced volume of any other storage tanks in the area.

When modifying an existing structure, label windows and doors to alert firefighters to the presence of pesticides and other products stored in the structure. It is always a good idea to keep a list of the stored chemicals and amounts in a separate location.

If a fire should occur, consider where the surface runoff water will go and where it might collect. For example, adding a curb around a floor can help confine contaminated water. In making the storage area secure, also make it accessible in order to help get chemicals out in a hurry.

Mixing and Loading Practices

Ground water contamination can result even from small spills in the mixing and loading area. Small quantities spilled regularly in the same place can go unnoticed, but the chemicals can build up in the soil and eventually reach ground water. By mixing and loading on an impermeable concrete surface most spilled pesticides can be recovered and reused.

A Mixing and Loading Pad