Reducing the Risk of Groundwater Contamination by

Fact Sheet 2

We'll look at five areas of pesticide management on your homestead: 1) pesticide storage practices; 2) mixing and loading practices; 3) spill cleanup; 4) container disposal practices; and 5) other management practices.

When handling pesticides, wear proper protective clothing at all times. Personal protection is not addressed in Home·A·Syst, because its focus is groundwater and drinking water protection. For more information on personal protection when handling pesticides, contact your county Cooperative Extension office or the nearest regional office of the Department of Labor and Industries. (see Contacts and References, page 6).

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 may pose a risk to groundwater.

The risk of contamination increases the closer the pesticide storage area is to your well. Pesticide storage areas should be downslope and as distant from your well as possible to provide reasonable assurance well water will not be contaminated. Separation 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. Several publications in the Contacts and References section provide more information on these topics. Also, worksheet 11, Site Evaluation, can help you rank your homestead soils and geologic conditions according to their ability to keep pesticides and other contaminants out of groundwater.

Proper management of your existing pesticide storage facility will often allow you to protect your water supply without major expense. Even when needed changes require expensive modifications to your facilities, keep in mind that compared to the cost of a contaminated well or a lawsuit, storage improvements can be a bargain.

The cheapest alternative you may have is to cut back on the amounts and types of pesticides stored, if practical. Also consider how you can protect the pesticides you keep in storage.

• Pesticide storage areas should be locked or pesticides stored in a locked cabinet out of reach of children and other unauthorized people. A locked storage cabinet or building provides security, prevents unauthorized use of pesticides and reduces the chance of accidental spills or theft. Provide signs or labels identifying the cabinet or building as a pesticide storage area. Areas in which pesticides labeled with the words "danger" or "poison" are stored are required by state law to be posted as a pesticide storage area. For further information, call the Washington State Department of Agriculture (WSDA), (360) 902-2040.
• Pesticides should always be stored in sound, properly labeled, original containers. 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 immediately.
• Steel shelves are easier to clean than wood if a spill occurs. Shelves for smaller containers should have a lip to keep the containers from sliding off.
• Store dry products above liquids to prevent wetting from spills. Never store dry bagged materials under liquids. Provide pallets to keep large drums or bags off the floor.
• Keep pesticides separate to prevent cross-contamination. Herbicides, insecticides and fungicides should be kept on separate shelves or areas.
• If you plan to store large bulk tanks, 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.

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 to store pesticides could compromise the safety of people and the environment. Storing pesticides in a separate facility reduces the risk associated with fire or accidental spills. Never store pesticides inside a wellhouse or a facility containing an abandoned well.

Fires in a storage area present a special hazard to people and the environment. You can reduce damages by anticipating emergencies. Entrances should be posted 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 pesticides and amounts stored. Keep a copy of the list in the house or away from the storage area and keep it up-to-date.

If a fire should occur, consider where the surface runoff water will go and where it might collect. For example, a curb around a floor can help confine contaminated water. When making the storage area secure, also make it accessible, so you can get pesticides out in a hurry should there be an emergency such as a fire.

Building a new facility just for pesticide storage may be expensive, but generally is safer than trying to modify areas meant for other purposes. If you build a new facility, apply the principles of safe pesticide storage mentioned above. Remember that this is your opportunity to provide the maximum amount of safety possible for your family and your drinking water supply.

Safe storage can minimize the risk of spills around your pesticide storage area. If a spill does occur, an impermeable (waterproof) floor, such as coated or sealed concrete, should virtually eliminate any seepage of pesticides into the ground. Putting a curb around the floor will prevent chemicals from spreading to other areas.

Secondary containment provides an impermeable floor and walls around the storagearea, which will minimize the amount of pesticide seeping into the ground if a bulk liquid pesticide storage tank should leak. Contact WSDA for specifics on secondary containment regulations (360) 902-2040.

A mixing/loading pad provides for secondary containment during the transfer of pesticides to spraying equipment.

For information on other factors to consider when designing a storage facility, such as ventilation, temperature control, and worker safety, contact your county Cooperative Extension office.

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Even if you don't have an impermeable 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 mix and load pesticides at the field to be sprayed using a nurse tank to transport water. Mixing should not be done in the same place continuously.
• 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 or gravel.
• Install a backsiphon prevention device on the well or hydrants to prevent reverse flow of liquids into the water supply. Never put the hose end inside the sprayer tank. Provide an air gap of six 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 the original container to applicator equipment (through a hose, for example). Humans and the environment are never inadvertently exposed to the pesticide with this system.
• Use rinsate for mixing subsequent loads. Spray the rinsate according to label directions. Ideally, rinsate should be used on the current application.

Containing pesticide spills and leaks requires an impermeable (waterproof) surface for mixing and loading. The pad should be large enough to contain leaks from bulk tanks, wash water from cleaning equipment, or to collect 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 rinsate (rinse water) storage tanks allows you to keep rinsate from different chemicals separate. That way, the rinsate can be used as mixing water on subsequent loads.

Locate the pad next to the storage area. 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 your county Cooperative Extension office or the Cooperative Extension agricultural engineer at (509) 335-2910 for more detailed information.

The Washington Spills Rule requires cleanup of a spilled or discharged dangerous waste or hazardous substance without intervention from the Department of Ecology (Ecology) unless assistance is required or requested. If the person responsible for a spill or discharge is uncertain of its possible significance, notification and/or request for assistance from Ecology is encouraged. It is also expected that control and stabilization of a spill or discharge (e.g. shutting off an open valve or righting an overturned drum) would come first, with notification of Ecology to follow.

For dry spills, promptly sweep up and use the pesticide as it was intended. Dry spills are usually very easy to clean up. For liquid spills, recover as much of the spill as possible. Recovery in the original liquid form is recommended. Otherwise use soil, sawdust or other absorbent material, and place it in a sealable container. It may have to be disposed of as hazardous waste. Contact your local health department for disposal procedures.

Spills are generally considered a threat to human health or the environment. Spills or discharges to water should be reported immediately. To determine how urgent clean up and notification of Ecology is, consider the possible rate of migration to ground water and proximity to wells and waterways. Spills to porous soils should be reported immediately. To allow a spill to simply evaporate is considered disposal and is a violation subject to full regulation under the Dangerous Waste Regulations.

Spills within or discharges to containment structures which are cleaned up in a timely manner typically do not need to be reported to Ecology. For example, shop floors, conrete pads, or drip pans could be considered barriers to the environment if they prevent contact with the environment. The Spill Rule does not allow you to use containment structures to store or accumulate dangerous wastes.

For further information or assistance or to report spills, contact the nearest regional office:

Central (509) 575-2490;
Eastern (509) 456-2926;
Northwest (206) 649-7000;
Southwest (360) 407-6300;
and the State Emergency Management Division—24-Hour Spill Number 1 (800) 258-5990.

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Unrinsed and improperly stored containers can lead to groundwater 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 minibulks and take them back to the dealer.
• Pressure-rinse or triple-rinse plastic and metal containers immediately after emptying, since residue can be difficult to remove after it dries. Pour rinse water into the spray tank. Puncture rinsed containers and store them in a locked, dry storage area until you can take them to a container recycling event or to a permitted landfill.
• 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.

Your drinking water is least likely to be contaminated if you follow appropriate management procedures and properly recycle or dispose of pesticide containers. Dispose of pesticide containers at approved facilities only to avoid risking contamination that could affect the water supplies and health of others.

(For more information about proper recycling or disposal of pesticide containers, refer to worksheet and fact sheet 5, Farm & Home Waste Management.)

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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, keeping records of what you have on hand, and using older products first.

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

Keeping accurate records of pesticide applications is required by state law. Contact WSDA at (360) 902-2040. Recordkeeping 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 field records, and 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.

Using older products first keeps your inventory current and effective. Before using chemicals that have been stored for a few years though, check with your county Cooperative Extension agent and WSDA at (360) 902-2030 about possible restrictions on their use. (Worksheet and fact sheet 5, Farm & Home Waste Management, provide information on how to safely and legally dispose of unused pesticides.)

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General pesticide information
National Pesticide Telecommunication Network, 1 (800) 858-PEST (-7378). Provides 24-hour information (365 days a year) on pesticide poisoning, pesticide products, pesticide cleanup and disposal, enforcement contacts, pesticide certification and training programs, and pesticide laws.

Washington Poison Control Center, 1 (800) 732-6985. The center provides information on who to contact in case of exposure to or spill of pesticides or any toxic substance.

Health effects of pesticides in drinking water
Washington Department of Health Consumer Assistance Hotline, 1 (800) 525-0127, is the department's general information contact for all health related issues.

Drinking water quality and treatment and health advisories
EPA Safe Drinking Water Hotline, Monday through Friday, 5:30 a.m. to 3 p.m. Pacific Standard Time. Call 1(800) 426-4791.

Further information on chemicals
Chemical Referral Center, sponsored by the Chemical Manufacturers Association. Call 1 (800) 262-8200. The Center will refer a caller to the manufacturer of the chemical in question. It will also provide telephone numbers of other hotlines that address chemicals.

Pesticide storage, handling, disposal, and safety
Your county Cooperative Extension office or the WSDA Pesticide Management Division, (360) 902-2050.

Washington Toxics Coalition has an extensive information file on many facets of chemical pesticides, including environmental fate and human health effects. Call (206) 632-1545.

State regulatory status of pesticides
Call WSDA Pesticide Management Division (360) 902-2030 for the regulatory status of farm chemicals registered for use in this state.

Pesticide spills
Your local Emergency Preparedness Coordinator/fire department should be contacted in the event of a spill. In the case of a spill of large magnitude, i. e., a ruptured barrel of liquid formulation, or if surface water or groundwater is threatened, call the Department of Ecology regional office for your area, listed on page 5.

Integrated pest management and non-chemical alternatives
Contact your local county Cooperative Extension office, the Washington Toxics Coalition at (206) 632-1545, or the Northwest Coalition for Alternatives to Pesticides at (503) 344-5044.

Pesticide Container Recycling
Contact the Washington State Department of Agriculture at (360) 902-2040 to ask about container recycling.

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Publications are available from sources listed at the end of the reference section. (Refer to number in parentheses after each publication.)

Groundwater contamination, protection and testing

Pesticide Movement in Soils-Groundwater Protection EB1543 (1)

Washington Groundwater: A Vital Resource EB1622 (1)

Protecting Your Groundwater: Survey Your Homestead Environment EB1631 (1)

Why The Concern About Agricultural Contamination in Groundwater? EB1632 (1)

Role of Soil in Groundwater Protection EB1633 (1)

Protecting Groundwater from Pesticide Contamination EB1644 (1)

Health effects

The product label. Read your product labels carefully for specific information on pesticide health effects.

Toxic Substances Fact Sheet: Pesticides, 1988. Washington Department of Health. (6) Discusses sources, types, uses, and health effects of pesticides.

Health Advisory Summaries. 1989. U.S. Environmental Protection Agency, Washington, D.C. (2)
Prepared for nearly 60 substances with potential to reach drinking water, each two-page Health Advisory Summary describes a pesticide, its brand names, its potential health effects, suggested action steps, and where to go for more information.

First Aid for Pesticide Poisoning, PNW0278 (1)

Pesticide storage, handling, disposal, and safety

Pesticide Mixing and Loading Options to Protect Water Quality EB1730 (1)

Safe Disposal of Home Use Pesticides EB1386 (1)

Protective Clothing for Pesticide User MISC0107 (1)

Your Home, Your Health, and Pesticides, 1990. (8)

A Consumer's Guide To Safer Pesticide Use. 1987. (3) Free 25-page special reprint from the EPA Journal.

Chemicals in Your Community: A Guide to Emergency Planning and Right To Know Act. 1988. (3) Contains information on implications of this law for farmers.

Disposing of Crop Protection Chemical Containers. 1990. (7) ACRE Fact Sheets, numbers 5 and 12. Fact Sheet 5 provides an eight-point check list of procedures to follow for safe disposal of chemical containers. Fact Sheet 12 discusses pressure-rinsed and triple-rinsed containers and rinsed container disposal.

Constructing an Inexpensive Chemical Rinse Pad. 1990. (7) ACRE Fact Sheet 14. Discusses capturing wastewater, storage of chemicals, site selection, and the design of a simple rinse pad.

Integrated pest management and other alternative pest control strategies

Puget Sound Pest Management Guidelines Manual, 1993. (1) A comprehensive manual that addresses chemical and integrated pest management (IPM) strategies, and costs and benefits of both.

Concepts of Integrated Pest Management in Washington, EB0753 (1)

The Washington Toxics Coalition provides an extensive information service on alternative pest control methods. (4)

Publications available from...

1. Your county Cooperative Extension office.
2. For information on how to obtain full health advisories or health advisory summaries, call the EPA's toll free Safe Drinking Water Hotline, 1(800) 426-4791, 5:30 a.m. to 3 p.m. Pacific Standard Time.
3. U.S. Environmental Protection Agency, Office of Pesticide Programs (TS-766C), 401 M Street S.W., Washington, D.C. 20460.
4. Washington Toxics Coalition, 4516 University Way NE, Seattle, Washington 98105.
5. Freshwater Foundation at Spring Hill Center, 725 County Road 6, Wayzata, Minnesota 55391, (612) 449-0092.
6. Washington Department of Health, Office of Toxic Substances, P.O. Box 47825, Olympia, Washington, 98504-7825, (360) 586-5401.
7. Alliance for a Clean Rural Environment (ACRE), P.O. Box 413708, Kansas City, Missouri 64141, 1 (800) 545-5410.
8. Washington Department of Ecology, Hazardous Waste & Toxics Reduction Program, P.O. Box 47600, Olympia, Washington 98504-7600, (360) 407-6700.

Home·A·Syst team members: Christopher F. Feise and Edward B. Adams, WSU Cooperative Extension Water Quality Coordinators; James D. LaSpina, Homestead Assessment System Project Associate.

Pesticide Storage & Handling Technical Reviewers: Roland Schirman, WSU Cooperative Extension; Wes Sieg, Washington Association of Wheat Growers; Gary Thomasson, WSU Cooperative Extension; Joe Hoffman, Washington State Department of Agriculture; Jim Lassen, Wilbur-Ellis.

Adapted for Washington from material developed by the Wisconsin, Minnesota, and Kansas Extension Services and Farm·A·Syst Programs. Washington Home·A·Syst development was supported by the National Farmstead Assessment Program.

Information derived from Home·A·Syst worksheets is intended only to provide general information and recommendations to rural dwellers regarding their own homestead practices. It is not the intent of this educational program to keep records of individual results.

Issued by Washington State University Cooperative Extension and the U.S. Department of Agriculture in furtherance of the Acts of May 8, and June 30, 1914. Cooperative Extension programs and policies are consistent with federal and state laws and regulations on nondiscrimination regarding race, color, religion, national origin, gender, age, disability, and gender preference. Evidence of noncompliance may be reported to your local Cooperative Extension office. Trade names have been used to simplify information; no endorsement is intended. Published September 1993. Subject Code 376. A. EB1746-F2