Pesticide Use and Risks
Pesticides – What are they?
Pesticides are chemicals that are sprayed on crops or in yards, buildings, or contained spaces to prevent damage from pests. Herbicides control weeds, insecticides control insects, fungicides help reduce damage from plant diseases, nematicides control nematodes, rodenticides control rodents, and other “…cides” control other pests like fleas, mollusks, and mites.
All the different “…cides” fall under the generic category “pesticides.”
Pesticides range from synthetic and highly toxic (e.g., chlorpyrifos) to natural and benign (e.g., baking soda). The synthetic pesticides typically sprayed by conventional farmers usually kill pests through some lethal mode of action. A growing number of pesticides work through a biochemical mode of action. These chemicals do not outright poison and kill pests, but rather disrupt their reproduction or development, or ability to feed in ways that undermine the ability of populations to reach damaging levels. As a general rule, biochemical pesticides that work through a non-lethal mode of action pose less risk to humans and the environment per acre treated.
Organic farmers use a limited number of natural pesticides approved by the USDA’s National Organic Program rule. Most work through a biochemical mode of action, or repel or discourage pest feeding. These pesticides are often not as effective as conventional pesticides, and as a result, organic farmers use them less regularly and depend instead on a combination of Integrated Pest Management (IPM) practices that prevent pests from reaching damaging levels.
Why worry about pesticide use?
The pesticides applied by conventional farmers often leave residues on plant tissues, including the edible portion of plants. A class of pesticides called “systemics” move into plants via their root systems and will be present inside the harvested part of a crop, even after washing and even cooking.
People are also exposed to pesticides in beverages, including drinking water and via dust and the atmosphere. Virtually every American has residues of a half-dozen to 10 or more pesticides in their bodies at any and all stages of life. Some of these residues can be overtly toxic to a number of organs or body systems, while others can disrupt normal fetal growth, as well as the development of infants and children, at very low doses.
For a half-century, toxicologists also asserted with confidence the ageless statement — “The dose makes the poison.” Today, scientists understand it is the dose and toxicity of a chemical, coupled with at what point in life an exposure happens, that determines whether harm will occur to human health.
Toxic, synthetic pesticides have been linked to health problems such as:
- Reproductive problems
- Birth defects
- ADHD and autism
- Nerve damage
- A suite of disorders affecting male reproductive organs
- Obesity and diabetes, and
Pesticides pose the greatest threat to developing fetuses, infants and children. The average American is exposed to 10-13 pesticide residues each day from food, beverages and drinking water.*
Pesticides of the Past
Remember DDT? DDT (Dichloro-diphenyl-trichloroethane) was once the most widely used pesticide in the US. Although it was discovered in 1874, it wasn’t used as a pesticide until after 1945, when it was heavily sprayed on crops such as cotton, peanuts and soybeans. It was also used to combat mosquitoes until the early 1970s, when it was phased out due to health concerns, adverse environmental effects and insect resistance.**
And, what exactly where those health concerns? Rachel Carson’s book, Silent Spring, published in 1962, broke the first news on the adverse impacts of DDT on birds and fish, and now there is a very long list of illnesses and damage either directly caused by exposure to DDT or made worse when people are also exposed to DDT.
Eating organic food and drinking filtered water is without doubt or debate the best way to ensure limiting your exposure to pesticides. Several studies have shown that measurable levels of one of the most toxic classes of insecticides disappear from the bodies of children after just a few days consuming a predominantly organic diet, but re-appear in 24 hours after switching back to conventional foods.
The Organic Center has a Shoppers Guide, a handy pocket-sized pamphlet to help you navigate the produce aisles and help you when choosing which produce has the least risk of toxic, synthetic pesticides.
For more information read The Organic Center’s new report: “Dietary Risk Index” — Tracking Relative Pesticide Risks in Foods and Beverages, September 2011.
(*Source: Simplifying the Pesticide Risk Equation: The Organic Option http://www.organic-center.org/reportfiles/OrganicOptionReport.pdf)
(**Source: DDT Regulatory History: A Brief Survey (to 1975) http://www.epa.gov/history/topics/ddt/02.htm )