Pesticides

These FAQs describe the potential harmful effects of pesticides and how you can be exposed to them. Reduce your pesticide exposure by buying organically grown produce, properly washing fruits and vegetables before you consume them, and by properly disposing pesticide containers. Alternative methods to control mosquitoes and other pests are provided, as well as the procedure to take to have your drinking or well water tested for pesticides.

In general, The Center for Environmental Oncology recommends not using chemical pesticides and trying alternatives first.

1. Are pesticides harmful to humans and the environment?
2. Can natural biological methods be used to control pests in agriculture?
3. How much pesticide residue is allowed on fruits and vegetables?
4. What steps can I take to reduce my exposure to pesticide residues?
5. What does "organically grown" mean?
6. Where can I have my drinking water tested for pesticides?
7. What is DEET?
8. What is DDT and how can we prevent mosquito bites without using DDT?
9. Are there other alternatives to pesticides?
10. What is pesticide spray drift?
11. What are the impacts of spray drift?
12. How can I get rid of the pesticides that I don't want anymore?
13. What are herbicides?
14. What are some safer alternatives to prevent and kill weeds?
15. Sources

Are pesticides harmful to humans and the environment?

Yes. The "-cide" in pesticide means "to kill." Pesticides, as a class of chemicals, are specifically designed to kill pests such as bacteria, insects and rodents. A considerable number of pesticides registered by the United States Environmental Protection Agency (EPA) contain suspected carcinogens. In addition, many pesticides are nerve poisons, which means they can impact the development of a child's brain. Recent research is beginning to reveal that some pesticides could be endocrine disruptors, which when absorbed into the body, either mimic or block hormones and disrupt the body's normal functions. Atrazine, for example.

One example of an endocrine-disrupting pesticide is atrazine, a heavily used herbicide in the United States. It was first approved for use as an herbicide in the U.S. in 1958. Because of concerns about toxicity, atrazine is banned in Europe. In the U.S., by contrast, the U.S. Environmental Protection Agency (EPA) estimates that 76 to 85 million pounds of atrazine are applied annually, mostly to corn, sorghum, and sugarcane fields.

Atrazine has been detected in many water systems throughout the world. People exposed to unsafe levels of the compound may develop diarrhea, eye or skin irritation, and stomach pain.

While the EPA has expressed concern about atrazine's potential hormonal effects, they have stated that atrazine is "not likely to be carcinogenic to humans." Dr. Tyrone Hayes, professor at the University of California, Berkeley has seen indications that doses of atrazine - in concentrations as low as one part per billion - inhibit the growth of the larynxes of male frogs and cause the formation of eggs in their testes. As hormone disruptors have been linked to cancer development in several studies, Dr. Hayes's work provides support to the idea that atrazine may cause cancer in humans.

Can natural biological methods be used to control pests in agriculture?

Yes. Organic food production limits the use of pesticides to those that are produced from natural sources, as opposed to synthetic chemicals.

You can employ Integrated Pest Management (IPM), which is a more environmentally responsible method of controlling pests. Effective, less risky pest controls are chosen first, including highly targeted pheromones to disrupt pest mating, or mechanical control, such as trapping or weeding. Click here for more information!

How much pesticide residue is allowed on fruits and vegetables?

The United States Department of Agriculture (USDA) and United States Food and Drug Administration (FDA) both monitor foods for pesticide residues and publish annual reports. Copies of the USDA Pesticide Data Program annual reports are available from the USDA. EPA sets limits on how much of a pesticide residue can remain on food. You can search a database of pesticide residue limits to learn what the residue limits are for your favorite foods.

The following conventionally grown fruits and vegetables contain the HIGHEST levels of pesticides. In general, it is best to buy thin-skinned fruits and vegetables organic. Limit your exposure to pesticides by buying these organic, especially:

• Apples
• Bell Peppers
• Winter Squash
• Green Beans
• Cantaloupe
• Cherries
• Grapes (imported)
• Nectarines
• Peaches
• Pears
• Potatoes
• Tomatoes
• Raspberries
• Spinach
• Strawberries

These conventionally grown fruits and vegetables contain the LOWEST levels of pesticides.

• Asparagus
• Avocados
• Bananas
• Broccoli
• Cauliflower
• Corn (sweet)
• Kiwi
• Mangos
• Onions
• Papaya
• Oranges
• Pineapples
• Peas (sweet)

What steps can I take to reduce my exposure to pesticide residues?

Washing, peeling, and trimming fruits and vegetables often will help reduce or remove any pesticide residues. For more information, read the fact sheet "Healthy, Sensible Food Practices."

What does "organically grown" mean?

"Organically grown" refers to food grown and processed using no synthetic fertilizers or pesticides. Pesticides derived from natural sources (e.g., biological pesticides) may be used to produce organically grown food. For more information, read the fact sheet, What "Organically Grown" Means. The United States Department of Agriculture (USDA) has issued standards for labeling of organically-grown crops.

Recent studies have shown that eating more organic food will reduce your exposures to pesticides, and the harm they can cause.

Where can I have my drinking water tested for pesticides?

If your water is from a public water supply, contact your water supplier or the state drinking water office located in your state environmental agency. They can tell you whether your water is regularly tested for a specific type of pesticide and how much, if any, has ever been found.

If you have a private well or if your water has not been tested for that type of pesticide, contact your state pesticide program. They can assist you in determining whether testing is warranted, choosing the type of analysis to be performed, identifying laboratories capable of performing the analysis, and determining the significance of testing results.

The publication Pesticides in Drinking-Water Wells (PDF) provides a step-by-step explanation of how pesticides can enter drinking-water wells, a list of the types of health concerns that pesticides can pose, and advise on testing your water supplies.

What is DEET?

DEET (chemical name, N,N-diethyl-meta-toluamide) is the active ingredient in many insect repellent products. It is used to repel biting pests such as mosquitoes and ticks, including ticks that may carry Lyme disease. The Reregistration of the Insect Repellent DEET fact sheet includes information for consumers on using this product safely. Information about using insect repellents safely is available in a general fact sheet by the EPA.

The U.S. Centers for Disease Control and Prevention recommends using repellents containing oil of lemon eucalyptus [p-menthane 3,8-diol (PMD)], a plant-derived active ingredient, as an alternative to commercial insect repellants. Note: Product labels containing this ingredient do not recommend using such repellants on children under the age of three.

What is DDT and how can we prevent mosquito bites without using DDT?

DDT (dichlorodiphenyltrichloroethane) is a pesticide once widely used to control insects in agriculture and insects that carry diseases such as malaria. Its use in the U.S. was banned in 1972 because of damage to wildlife, but is still used in some countries. The International Agency for Research on Cancer (IARC) determined that DDT may possibly cause cancer in humans.

Methods include using netting on beds, screens on windows, and double lock chambers on doors to stop bites.

Mosquitoes will develop in any puddle that lasts more than four days. You should cover standing water near pumps and install septic tank systems and simple drains to decrease the amount of standing water.

Replace outdoor lights with yellow "bug" lights. Wear headnets, long sleeve shirts, and long pants if venturing into areas with high mosquito populations, such as salt marshes or wooded areas. Use mosquito repellents when necessary, according to their label instructions.

Are there other alternatives to pesticides?

Click here for our "Alternatives to Pesticides" table

What is pesticide spray drift?

The EPA defines pesticide spray drift as the physical movement of a pesticide through air at the time of application or soon thereafter to any site other than that intended for application (often referred to as "off target"). The EPA does not include in its definition the movement of pesticides to off-target sites caused by erosion, migration, volatility, or contaminated soil particles that are windblown after application, unless specifically addressed on a pesticide product label with respect to drift-control requirements.

What are the impacts of spray drift?

Off-target spray can affect human health and the environment. For example, spray drift can result in pesticide exposures to farm workers, children playing outside, and wildlife and its habitat. Drift can also contaminate a home garden or another farmer's crops, causing unhealthy pesticide residues and/or plant damage. The proximity of individuals and sensitive sites to the pesticide application, the amounts of pesticide drift, and toxicity of the pesticide are important factors in determining the potential impacts from drift.

If there is drift, or you suspect drift, of a pesticide onto you or your property, call your state agency to file a pesticide misuse complaint. Ask them to send an investigator.

How can I get rid of the pesticides that I don't want anymore?

Follow any specific disposal instructions on the label of the pesticide or bring it to a local hazardous waste collection center. In Pittsburgh, you can contact the Pennsylvania Resource Center (PRC) at www.prc.org, who conduct 4 hazardous waste collections a year, The EPA and local governments sometimes hold special pesticide collection days (click on your home state on the map in this link) when you may drop-off unwanted pesticides free of charge for proper disposal. For more information, see Safe Disposal of Pesticides.

What are herbicides?

Herbicides are synthetic chemicals that control weeds. Some naturally-occurring chemicals, such as copper sulfate, also have the potential to control weeds, but the term herbicide is reserved for chemically synthesized compounds.

What are some safer alternatives to prevent and kill weeds?

As some commercial herbicides can pose significant health risks, the following options are safer alternatives you can use to prevent and kill weeds:

Mulch:

Covering garden soil with mulch blocks weeds. Use two or three inches of shredded bark, wood chips, straw, cocoa bean hulls, gravel or rocks. The mulches will also keep moisture in the soil, so you will have to water less frequently.

Boiling Water:

Douse weeds with boiling water. Weeds, like humans, will burn if exposed to boiling water. This method also kills weed seeds.

Soap:

Mixed 5 tablespoons of nontoxic liquid soap in one quart (4 cups) of water in a spray bottle. Coat the weeds with the soapy water. Works best on hot days.

Vinegar:

Pour household vinegar into a spray bottle and evenly coat weeds with it. U.S. Department of Agriculture scientists recently confirmed this in tests. Vinegar is really five percent acetic acid in water, and it burns the plant, especially on sunny days. For extra strength weed killer, look for pickling vinegar, which is nine percent acetic acid. Don't get the vinegar on your garden plants, as it can kill them too.

Alcohol:

Mix one to five tablespoons of alcohol--depending on how stubborn the weeds are to kill--with one quart (4 cups) of water in a spray bottle. Shower weeds with the spray. Don't let the alcohol get on garden plants as it may damage their leaves.

Corn meal gluten:

Use it as a pre-emergent herbicide and fertilizer. Corn meal gluten prevents weeds from growing, and then breaks down to provide nitrogen to your plants or lawn. Use it on lawns or established perennial beds, as it won't kill already growing plants. That does mean, of course, that it will not work on already existing weeds.

Sources:

• Agency for Toxic Substances and Disease Registry (ATSDR). U.S. Department of Health and Human Services, Public Health Service. 2002 Sep. ToxFAQs™: DDT, DDE, and DDD. Accessed 2008 Mar 20.
• Blumenstyk G. 2003. The price of research: A Berkeley scientist says a corporate sponsor tried to bury his unwelcome findings and then buy his silence. The Chronicle of Higher Education 50(10): A26. (Alternate link)
• Centers for Disease Control and Prevention, National Center for Zoonotic, Vector-Borne, and Enteric Diseases, Division of Vector Borne Infectious Diseases. Department of Health and Human Services. 2006 Apr 18. Updated Information regarding Insect Repellents. Accessed 2008 Mar 20.
• Curl CL, Fenske RA, Elgethun K. 2003. Organophosphorus pesticide exposure of urban and suburban preschool children with organic and conventional diets. Environmental Health Perspectives 111(3): 377-82.
• DuPont Biotechnology. Frequently Asked Questions about Herbicide Resistant Crops and Weed Management. Accessed 2008 Mar 20.
• Healthy Child Healthy World (formerly CHEC). Health eHouse. Accessed 2008 Mar 20.
• Healthy Child Healthy World (formerly CHEC). Kill Weeds without Herbicides. Accessed 2008 Mar 20.
• U.S. Environmental Protection Agency, Office of Pesticide Programs. 2008 Mar 13. Integrated Pest Management (IPM) Principles. Accessed 2008 Mar 20.
• U.S. Environmental Protection Agency, Office of Pesticide Programs. 2007 Oct 16. Frequently Asked Questions: Consumers. Accessed 2008 Mar 20.
• World Health Organization. 2006. Malaria vector control and personal protection : Report of a WHO study group.. Geneva: World Health Organization. WHO Technical Report Series nr 936.

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