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Improving Pesticide Storage and Handling

Pesticide Storage • Mixing and Storing Practices • Cleanup Procedures • Container Disposal • Other Managing Practices

We'll look at five areas of pesticide management on your farmstead:

• pesticide storage practices;
   
• mixing and loading practices;
   
• spill cleanup;
   
• container disposal practices; and
   
• other management practices.

When handling pesticides, wear proper protective clothing at all times. Personal protection is not addressed in Farm*A*Syst, because its focus is groundwater and drinking water protection.

1. Pesticide storage practices

If stored safely in a secure location, pesticides pose little danger to groundwater. Common sense suggests keeping them dry and out of the way of activities that might knock over a jug or rip open a bag. Short-term storage (during seasonal use) poses a lower risk than year-round storage, but any storage, regardless of length of time stored, poses a risk to groundwater.

If a spill does occur, an impermeable (waterproof) floor, such as properly sealed and backed concrete, with a curb should virtually eliminate any seepage of chemicals into the ground and prevent chemicals from spreading to other areas.

Secondary containment provides a concrete floor and walls around the storage area, which will minimize the amount of pesticide seeping into the ground if a bulk liquid pesticide storage tank should leak. A mixing/loading pad provides for 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 generally it will be safer 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 well. Separation from the well should be greater if the site has sandy soils or fractured bedrock near the land surface. The risk of pesticide contamination of groundwater is influenced by properties of both the pesticide and the soil on which it is spilled or applied.
   
• In the event of a fire, contaminated surface water should drain to a confined area.
   
• The mixing and loading area should be close to your storage facility, to minimize the distance that chemicals are carried.
   
• The storage building foundation and secondary containment floor should be well drained and above the water table. The finished grade should be 3 inches below the floor level and sloped to provide surface drainage away from the building.
   
• Provide pallets to keep large drums or bags off the floor. Shelves for smaller containers should have a lip to keep the containers from sliding off. Steel, plastic, or poly shelves are easier to clean than wood if a spill occurs. Store dry products above liquids to prevent wetting from spills.
   
• If you plan to store uncovered large bulk tanks, provide a containment area large enough to confine 125 percent of the volume of the largest bulk container, plus the volume occupied by any storage tanks in the containment area. If bulk tanks are under cover, the containment should confine 110 percent of the volume of the largest bulk container, plus the volume occupied by any storage tanks in the containment area.
   
• A locked storage cabinet or building provides security. Preventing unauthorized use of pesticides reduces the chance of accidental spills or theft. Provide signs or labels identifying the cabinet or building as a pesticide storage area. Labels on the outside of the building give firefighters information about pesticides during an emergency response for fire or a spill.
   
• 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 different 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 Midwest Plan Service at 1-800-562-3618.

Modifying an existing storage facility

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. Items 5-10 above are important points to remember for modifying existing storage.

The cheapest alternative you may have is to cut back on the amounts and types of pesticides stored. If that's not practical, consider how you can protect the pesticides you keep in storage. Sound containers are your first defense against a spill or leak.

If a container is accidentally ripped open or knocked off a shelf, the spill should be confined to the immediate area and cleaned up promptly. The building should have a solid floor and, for liquid pesticides, a curb. The secondary containment space should be large enough to hold 125 percent of the contents of the largest full container, plus the volume occupied by any storage tanks in the containment area.

Remodeling existing facilities that serve other uses may be less expensive than building a new facility, but remodeling can be complicated. When existing buildings must accommodate other activities, using them also 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 any facility containing a well or water supply.

You can reduce damages by anticipating emergencies. Fires in a storage area present a special hazard to people and the environment. If containers are damaged, the stored chemicals may leak out and spread over a large area.

Windows and doors should be labeled to alert firefighters to the presence of pesticides and other products stored in the structure. It's a good idea to keep a list of the chemicals and amounts stored. Keep a copy of the list in the house or away from the storage area.

If a fire should occur, consider where the surface runoff water will go and where it might collect so that a curb around the floor can be used to help confine contaminated water.

In making the storage area secure, also make it accessible, to allow getting chemicals out in a hurry.

2. Mixing and loading practices

Groundwater 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 groundwater or run off into surface water. By mixing and loading on an impermeable surface, such as concrete, you can contain and reuse most spilled pesticides.

A mixing and loading pad

Containing pesticide spills and leaks requires a concrete pad surface for mixing and loading. The pad should be large enough to contain leaks from bulk tanks, wash water from cleaning equipment, and spills from transferring chemicals to the sprayer or spreader. (See Figure 1.)

The size of the pad depends also on the equipment you use. It should provide space around the parked equipment for washing and rinsing. Having several separate rinsate (rinse water) collection and storage tanks allows you to keep rinsate from different chemicals separate so they can be used as mixing water on subsequent loads.

Locate the pad next to the pesticide storage area and make sure that any water from the pad will flow away from the well. At sites where runoff water could reach the well, construct a diversion so runoff is directed to another area.

If you are considering constructing a mixing and loading pad, contact the Midwest Plan Service at 1-800-562-3618.

Better management on your existing mixing and loading site

Spills and leaks are bound to occur from time to time. Even if you don't have a concrete mixing and loading pad, you can minimize contamination by following some basic guidelines:

Avoid mixing and loading pesticides near your well. One way to do this is to use a nurse tank to transport water to the mixing and loading site. Ideally, the mixing site should be moved each year within the field of application.

Avoid mixing and loading on gravel driveways or other surfaces that allow spills to sink quickly through the soil. A clay surface is better than sand.

Install a backflow prevention device on the well or hydrants to prevent reverse flow of liquids into the water supply. Never put the hose in the sprayer tank. Provide an air gap of 6 inches between the hose and the top of the sprayer tank.

Always supervise sprayer filling. For restricted-use pesticides, a trained and certified applicator must supervise operations.

Consider a closed handling system, which transfers the pesticide directly from storage container to applicator equipment so that humans and the environment are never inadvertently exposed to the pesticide.

Use rinsate for mixing subsequent loads, and spray the last rinsate load on the labeled crop.

3. Spill cleanup procedures

Dry spills are usually very easily cleaned up by promptly sweeping up and reusing the pesticide as it was intended.

For liquid spills, first stop the leakage, and then keep the spill from spreading by building a small dike out of soil around the spill area. Clean up the spill with some kind of absorbent material; i.e., kitty litter, sawdust, or oil-soak material, and then scatter the absorbent material widely over a site specified on the pesticide label. Cover the spill area with activated charcoal which neutralizes the pesticide.

If deeper soil contamination occurs, remove the contaminated soil, cover the area with lime, and cover the lime with uncontaminated soil. The contaminated soil should be scattered widely over a site specified on the pesticide label.

Develop an emergency response plan for the site that includes knowing where runoff water will go, knowing how to handle your particular chemicals, and whom to call for help. Pesticide spills endangering the property of others or water supplies (whether ground or surface water) should be reported immediately to the Office of Emergency Services at 1-374-1201.

4. Container disposal practices

Unwashed and improperly stored containers can lead to water contamination by allowing chemical residues to leak onto the ground. Some basic guidelines can help avoid similar problems:

As often as possible, use returnable containers and mini-bulks and take them back to the dealer.

Pressure-rinse or triple-rinse plastic containers immediately after use, since residue can be difficult to remove after it dries. Pour rinse water into the spray tank. Puncture containers and store them in a covered barrel until you can take them to a permitted landfill.

• Recycle plastic and metal containers whenever possible.
   
• Shake out bags, bind or wrap them to minimize dust, and take them to a permitted landfill.
   
• Do not bury or burn pesticide containers or bags on the farm.
   
• Cooperating groups and agencies sometimes sponsor collection days that serve as a good method for disposing of unwanted chemicals and containers.

5. Other management practices

Reducing pesticide waste makes financial as well as environmental sense, but it means more than just reducing spills. It also means not buying more than you need to apply, using older products first, and keeping records of what you have on hand.

Buying only what you need makes long-term storage unnecessary. In addition, you avoid cold weather problems, which can make some pesticides useless.

Using older products first keeps your inventory current and effective. Before you use chemicals that have been stored for a few years, check with your chemical representative or your county Extension agent about possible restrictions on their use.

Record keeping may seem like a task unrelated to groundwater contamination, but knowing what you've used in the past and what you have on hand allows you to make better purchasing decisions. Provisions in the 1990 Farm Bill require pesticide application record keeping for restricted-use pesticides. Efforts are being made to develop a standard record keeping form to make available to pesticide users. Until it is available, the following general guidelines are suggested.

Keep records of past field application rates and their effectiveness. Along with field records, you can add information such as the manufacturer's name and address, chemical types, and handling precautions. This information can be important if you must respond quickly to an accident.