Virginia Farmstead Assessment System*

Fact Sheet No. 7 Pesticide Storage, Handling, and Management

Technical Reviewers: Kathy Dictor, Donald R. Delorme and William E. Walls (Virginia Department of Agriculture and Consusmer Services, Richmond, Virginia).

Publication Number 442-907, June 1996

*Overview of the Virginia Farm Assessment System

Table of Contents

Introduction

I. Pesticide Storage Practices

II. Mixing and Loading Practices

III. Spills and Cleanup Practices

IV. Unwanted Pesticide and Container Disposal

V. Field Pest Management

VI. Other Management Considerations

Contacts and References

Glossary No. 7

Appendix A

Worksheet No. 7

Introduction

Taking voluntary action to prevent pesticide contamination of groundwater will help assure the continued availability of pesticides for responsible use. Drinking water is least likely to be contaminated if appropriate management procedures are followed or pesticide wastes are properly disposed. Proper off site disposal practices are essential to avoid risking contamination of groundwater that could affect water supplies and the health of others. Figure 1 illustrates a well-designed facility for pesticide storage and handling.

Return to Table of Contents

I. Pesticide Storage Practices

If a spill does occur in a storage area, an impermeable (waterproof) floor, such as concrete, will prevent chemical seepage into the ground. Putting a curb around an impermeable floor will prevent chemicals from spreading to other areas.

Secondary containment will provide an impermeable floor and walls around the storage area, and it will minimize the amount of pesticide seeping into the ground if a bulk liquid pesticide storage tank leaks.

A. BUILDING A NEW STORAGE FACILITY

When building a new facility, keep in mind a few principles of safe pesticide storage:

1. Locate the building downslope and at least 100 feet away from the water well or spring. Separation from the water source should be greater if the site has sandy soils, fractured bedrock, or sinkholes near the land surface. The risk of pesticide contamination of groundwater is influenced by properties of both the pesticide and the soil.

2. In the event of a fire, contaminated runoff water should drain to a confined area.

3. The pesticide mixing and loading area should be close to the pesticide storage facility, to minimize the distance that chemicals are carried.

4. The building foundation or secondary containment floor should be well drained and located 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.

5. Pallets should be provided 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 shelves are easier to clean than wood if a spill occurs. Dry products should be stored above liquids to prevent wetting from spills.

6. For large bulk tanks, a containment area should be 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.

7. A locked storage area or building provides security. Preventing unauthorized use of pesticides reduces the chance of accidental spills or theft. Signs or labels should be provided to identify the area as a pesticide storage area. Labels on the outside of the building give fire fighters information about pesticides during an emergency response for fire or a spill. It's a good idea to keep a list of the chemicals and amounts stored. Keep a copy of the list in a building away from the storage area.

8. Adequate road access should be provided for deliveries and access by emergency equipment.

9. Various pesticides should be kept separate, according to pesticide type, to prevent cross-contamination. Herbicides, insecticides and fungicides should be kept on separate shelves or areas.

10. 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.

B. MODIFYING AN EXISTING STORAGE FACILITY

When an existing building must accommodate other activities, pesticide storage could compromise the safety of people and the environment. For example, fire in a storage area presents a special hazard to people and the environment. Storing chemicals in a separate facility reduces the risk associated with fire or accidental spills. Pesticides should never be stored inside a well/pump house or a facility which contains an abandoned well.

Return to Table of Contents

II. Mixing and Loading Practices

To contain pesticide spills and leaks, an impermeable (waterproof) mixing and loading pad is required. 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. The size of the pad depends also on the equipment used. It should provide space around the parked equipment for washing and rinsing.

The pad should be kept clean. Rainfall can mix with spilled pesticides and therefore the runoff may require proper disposal. Storage of rainfall increases the required size of the sump.

The pad should be located next to the storage area. Water from the pad should be diverted away from the well. At sites where runoff water could reach the well, a diversion should be constructed.

Spills and leaks of pesticides are bound to occur from time to time. Even if there is no impermeable mixing and loading pad, groundwater contamination can be minimized by following some basic guidelines:

• Avoid mixing and loading pesticides near a water well or spring. 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.

• Avoid mixing and loading near a sinkhole.

• Install an anti-backsiphon device on the well and hydrants. 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 licensed applicator must supervise operations.

• Consider a closed handling system, which transfers the pesticide directly from storage container to applicator equipment (through a hose, for example).

• Use rinsate for mixing subsequent loads.

Return to Table of Contents

III. Spills and Cleanup Practices

For liquid spills, recover as much of the spill as possible and reuse as it was intended. It may be necessary to remove contaminated soil from clay pads. There should be sawdust or cat litter available for concrete pads to adsorb unrecovered liquid. Have an emergency response plan for the site. Know where the runoff water will go, how to handle your particular chemicals, and whom to call for help.

A confined mixing and loading area, such as a sump, allows settling before transfer to rinsate storage tanks. Having several rinsate storage tanks allows rinsate from different chemicals to be stored separately. Rinsate can be used as mixing water on subsequent loads.

Return to Table of Contents

IV. Unwanted Pesticide and Container Disposal

Unwashed and improperly stored containers can lead to groundwater contamination if chemical residues are allowed to leak into the ground.

Some basic guidelines can help avoid problems:

• As often as possible, use returnable containers and minibulks, and return empty containers to the dealer.

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

• Recycle plastic and metal containers whenever possible.

• Shake out bags, bind or wrap them to minimize dust, and take them to a licensed landfill.

• Do not bury pesticide containers or bags on your property or dispose of them in sinkholes.

Return to Table of Contents

V. Field Pest Management

Best Management Practices (BMP's) should be the basis of your pest control program. Sound practices include periodic calibrating of pesticide spray equipment, and considering soil moisture conditions, particularly if applying liquid chemical through an irrigation system (chemigation), and taking note of impending weather conditions.

Integrated Pert Management (IPM) is an interdisciplinary approach to pest control, incorporating the judicious application of management techniques, environmental principles, and biological and chemical methods to maintain pest populations at tolerable levels. Among the basic tenets of IPM for reducing pesticide use are more efficient application methods, pesticide application based on economic thresholds, use of resistant crop strains, timing of field operations (planting, cultivating, harvesting), researching crop-pest ecosystems, monitoring and surveillance of pests, use of biological controls (introduction of natural enemies, preservation of predator habitats, release of sterilized male insects, use of pheromones), crop rotation, use of attractant crops, habitat diversification, use of botanicals, and destruction of pest breeding, refuge and overwintering sites.

When pesticide applications are necessary and a choice of registered materials exists, consider the persistence, toxicity, runoff and leaching potential of products when making a selection (see Appendix A). Conservation plans take into account the leach potential of soils on the farm and the leachability of pesticides to illustrate how the risk of pesticide contamination can be reduced in selecting pesticides to use.

Return to Table of Contents

VI. Other Management Considerations

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

• 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. Keep records of past field application rates and their effectiveness.

• Keep records on other information such as the manufacturer's name and address, pesticide types and handling precautions. This information can be important if you must respond quickly to an accident.

• Use older products first to keep your inventory current and effective. Before using chemicals that have been stored for a few years, though, check with your county Extension agent about possible restrictions on their use.

Return to Table of Contents

Contacts and References

Acknowledgements

Return to Table of Contents

View a list of the Virginia Farmstead Assessment System publications