You just heard that pesticides are being broadcast in your neighborhood. Do you: a) turn off your radio or television; b) get the kids and pets inside and seal the windows; or c) go on doing whatever you'd been doing because that stuff kills bugs, not people? For the past few years around Long Island Sound this has not been a casual question, as fears of insect-borne diseases have resulted in massive pesticide sprayings to control mosquitoes. These highly visible incidents of pesticide use are only a small fraction of the total volume of pesticides used in our landscapes and the more people seek to learn about pesticides and their effects, the more questions are raised.

Pesticides may target insects (insecticides), plants (herbicides), fungus (fungicides), bacteria (bactericides or disinfectants), even rodents (rodenticides), or basically any organism that humans don't want in a specific area. People who worry about pesticides in the environment tend to assume most of these chemicals are being used in agriculture or on recreational areas like golf courses. In fact, research has shown that, on an acre by acre basis, the average homeowner uses up to TEN TIMES the amount of pesticides as these other landowners.

Go into any hardware or gardening supply store and you will be confronted with shelves filled with different products to eliminate ants and termites from the home, grubs or dandelions from the lawn and so on. The Environmental Protection Agency (EPA) estimates that over SEVENTY MILLION POUNDS of pesticides are applied to residential landscapes every year. While nearly fifty different pesticide formulas are commonly used on residential properties, a handful (the herbicides 2,4-D and MCPP and insecticides diazinon and chloropyrifos) make up the bulk of the pesticides used. Perhaps not surprisingly, these are the pesticides that regularly show up in water samples from urban and suburban streams.

Pesticide products are registered by the EPA, but such registration is NOT a consumer product safety program. In fact, the EPA has listed 90-95% of the active ingredients in its registered pesticides as "possible" or "probable" carcinogens. Studies all over the world are linking pesticide exposure to cancers like brain cancer, leukemia and non-Hodgkin's lymphoma. Many of these products were registered before 1978 when Congress strengthened pesticide testing requirements, so they have not been tested for environmental impacts, neurotoxicity or hormone disruption. What testing is done examines the active ingredients individually and does not take into account exposure to multiple pesticides. Exposure guidelines also assume those exposed are healthy young adult males who would be less susceptible to toxic effects than small children or the elderly.

While quite a few pesticides have been banned from all uses (DDT, etc.), products like diazinon, which was banned for use on golf courses and sod farms after massive bird mortalities, are still available for use by untrained homeowners. Unfortunately, just deciding not to use pesticides will not protect you from pesticide exposure. Pesticides do not tend to stay where they are applied and studying pesticide "loss" keeps many researchers busy. Pesticides applied as a spray are subject to"drift" where 2-25% of the material blows away from the spray site. Once pesticides are on the ground, a sudden rainstorm can cause"runoff," washing the pesticide into a nearby stream or wetland, or "leaching" of the pesticide into the groundwater where it can cause well water contamination. A study of pesticide contamination of residential well water in Connecticut found that 11% of the wells had detectable levels of pesticides. One well contained five different pesticides and that homeowner was using organic gardening practices. A California study found that if as few as 2% of homeowners in a watershed used diazinon in lawn care, toxic concentrations were found in the streams.

One final idea to consider is that the heavy use of pesticides (and fertilizers) to create perfect lawns only started after WWII, and is an example of a socially accepted practice that needs to be reconsidered. As Michael Surgan, Ph.D., Chief Environmental Scientist for the New York State Attorney General put it, "If you buy the notion that we have to accept a certain amount of risk from pesticides to safeguard the food supply [or prevent the spread of disease], that's one thing. But with lawns, people are applying carcinogens simply for the sake of aesthetics. That's got to change."

Written by Heather M. Crawford

Coastal Resources Educator

Connecticut Sea Grant Extension Program

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Last updated 18 September, 2004 .