What kinds of pesticides did the CDC test for in the U.S. population?

CDC scientists tested the blood and urine of hundreds of people in the U.S. for four types of pesticides: organochlorines, organophosphorus compounds, carbamates and pyrethroids. They also tested for a few widely used weed killers and other pesticides that don’t fall into any of these categories.

• Organochlorine pesticides have a long history of widespread use in the U.S. and around the world. These compounds are typically very persistent in the environment, and are known for accumulating in sediments, plants and animals. Organochlorines have a wide range of acute and chronic health effects, including cancer, neurological damage, and birth defects. Many organochlorines are also suspected hormone system disruptors.
• Organophosphorous (OP) pesticides account for about 70% of the insecticides in current use in the United States, a total of around 90 million pounds per year. When OP pesticide breakdown products are found in body burden tests, it reflects recent exposure to an OP pesticide - within days of the sample being taken. While these chemicals do not persist for long periods in the environment, their widespread use means that they are frequently passing through our bodies. OP pesticides work by interfering with the nervous system of insects, a mechanism that also affects the human nervous system when people are exposed. Other health effects of individual OP pesticides vary; some are highly acutely toxic, some cause development or reproductive harm, and some are known or suspected endocrine disruptors.
• Carbamate insecticides are very similar to the organophosphorus compounds in their effects on the human nervous system. They interfere with the transmission of nerve impulses. There are several different kinds of carbamates. The N-methyl carbamates are the most acutely toxic. Some chemicals in this class are hormone disruptors and/or carcinogenic as well.
• Pyrethroids are a widely used class of pesticides applied in agricultural settings, homes, and for the control of some parasites. Pyrethroids work by paralyzing the nervous systems of insects. Predator insects that keep problem pests in check are often more sensitive to these insecticides than the pests themselves. Because pyrethroids are structurally similar to pyrethrins which are extracted from chrysanthemums, manufactures often mislead consumers to believe that pyrethroids are as safe as chrysanthemums. In fact, they are the second most common class of pesticides that result in poisoning, including negative effects on the central nervous system (e.g., loss of consciousness and/or seizures). Pyrethroids are also a skin irritant, and exposure can result in abnormal skin sensations including itching, tingling, stinging, burning and numbness.

For the full list of pesticides and pesticide breakdown products covered in the CDC study, see below. For more in-depth information on key pesticides in the report, see our Pesticide Fact Sheets.

How are people exposed to these pesticides?

• Food Residues: Pesticide residues in food are a major source of pesticide exposure. In a recent analysis of selected organochlorine pesticide residues in the U.S. food supply, Pesticide Action Network found that even chemicals that have been banned for decades show up consistently in food samples tested by the U.S. Food and Drug Administration. This can be explained in part by the long life of many organochlorines in the environment, and in part by long distance transport in wind and water currents—as well as on imported foods—of pesticides that continue to be used in other countries.
• Water: Water contaminated with pesticides is another source of exposure. Drinking water supplies can be polluted with runoff from both agricultural and urban use of pesticides. The herbicide atrazine, for example, is widely used on field crops in the Midwest, and the pesticide is found in many municipal and private wells in the region. Across the U.S., pesticide run-off from agriculture is a well-documented source of water contamination. States where the pesticide lindane is still allowed for use in lice shampoos face water contamination as well: a single use of lindane shampoo contaminates an estimated six million gallons of water.
• Agricultural pesticide applications: Agricultural workers and communities can be exposed during and after pesticide applications. Workers that weed or harvest crops recently sprayed with pesticides—or those working in neighboring fields during application—can inhale the pesticides or absorb them through their skin. People in communities and schools located near farms where pesticides are sprayed may inhale fumes from the applications or come in contact with residues of spray drift that have settled in their yards or homes.
• Home pesticide use: Pesticide use in the home also results in exposure. Consumers apply pesticides on lawns and gardens, in the home to control ants, roaches and other pests, and on household pets to control ticks and fleas. Some pesticides, like the insecticide lindane, are active ingredients in medicinal shampoos and soaps (for control of lice and scabies). Pesticides used in the home can be absorbed through skin contact, inhalation, or accidental ingestion.

If I have these pesticides in my body, will I get sick?

You might, but not necessarily right away. One in four people in the U.S. today will contract cancer during their lifetime, and scientists don’t know how much of this cancer is caused by exposure to pesticides. What is clear is that with the dramatic increase in chemical use in the last several decades there has been a parallel increase in the incidence of diseases that are associated with environmental contamination.

Individuals vary widely in their sensitivity to individual chemicals, and it is difficult to predict the specific effects of long term, low-level exposures. The pesticides the CDC is looking for in people’s bodies have a wide range of known health effects, including cancer, birth defects, neurological damage, infertility and weakened immune systems. Scientists estimate that everyone alive today carries within her or his body at least 700 contaminants, most of which have not been well studied. There are insufficient studies on the possible health effects of exposure to multiple chemicals.

What is better understood is how individual chemicals can harm infants and children. Surprisingly low levels of exposure to young children or fetuses in the uterus can cause irreversible damage if the exposure occurs when a certain organ or system is in a critical stage of development. The effects of this damage may not become apparent until later in life—a specific example is infertility or other damage to the reproductive system.

What is being done to reduce the use of these pesticides?

In response to the Food Quality Protection Act of 1996, the U.S. EPA began a process of re-registering pesticide active ingredients using a new set of standards that are more protective of public health than those used before 1996. One result is the requirement that combined exposure to pesticides with a common mechanism of toxicity (like the organophosphorus insecticides) be considered. Unfortunately, there is still no mechanism to account for the many simultaneous exposures to different groups of chemicals people experience every day.

The good news is that new restrictions have been imposed on most pesticides evaluated under the law. Some uses (such as residential uses of diazinon and chlorpyrifos) are being phased out altogether because of the unacceptable risks posed to children from their use. The bad news is that the process is slow, so many high-use chemicals have yet to be evaluated. Unfortunately, the risks to agricultural workers are often simply overlooked. EPA has also not followed the letter of the law in its work, failing to fully assess the risks from all routes of exposure and failing to include additional safety factors for children that are required under the 1996 law.

Industry’s attempts to delay enforcement of the law were successfully blocked by a lawsuit filed by the Natural Resources Defense Council, Pesticide Action Network, CalPIRG, Breast Cancer Fund, United Farm Workers, and Physicians for Social Responsibility. The settlement of the lawsuit in 2001 puts EPA on a strict timeline to finish the work for many high-use chemicals. The agency will be pressured to make some hard decisions in the next several years as the data come in. If the law is properly implemented, we may see significant new restrictions and reductions in pesticide use.

What should we be using instead?

Many safer alternative pest control methods have proven effective in a variety of environments. Organic agriculture is a rapidly growing sector of the agricultural economy that successfully produces healthy food without the use of synthetic pesticides. Many techniques in the home and garden can be used to avoid pesticide application as well. These methods use common sense approaches to create an environment that discourages pests.

For example, some of the most common pests in the home can be reduced by using a few simple rules. First, identify the pest. Next, eliminate its access to the house. Third, eliminate the food source. Fourth, eliminate the water source. These simple steps can help you prevent infestations without using pesticides that can harm you, your family, and the environment.

The same basic preventive approach can be used for lawn care. If you want to have a lawn, some easy rules of thumb can help reduce or eliminate use of pesticides. Organic lawn care, like organic agriculture, depends on keeping the soil healthy and biologically active, teeming with all kinds of beneficial insects and microorganisms. Using pesticides and fertilizers can “kill” the soil, weakening the plants and inviting pests. To keep soil healthy, avoid chemicals and use careful mowing, watering, and feeding techniques.

There are many things we can do to reduce the use of pesticides. We can use alternatives in our own homes, protecting our families from direct exposure. We can encourage the use of alternatives in agriculture by buying organic food and clothing. We can urge the agricultural industry and government officials to invest in research and promotion of alternatives, and let them know that we do not accept the use of toxic pesticides.

For more information and resources on reducing pesticide use at home, see PAN’s Pesticide Advisor.

What pesticides did the CDC test for?

Forty-three of the 148 chemicals CDC studied in the 2005 study are pesticides and their breakdown products. Where CDC tested for a breakdown product, we indicate in parentheses the pesticide that creates this metabolite. For most of the breakdown products listed below, clicking on a chemical name will take you directly to the PAN Pesticide Database for more detailed information.

Dimethylphosphate
Dimethylthiophosphate
Dimethyldithiophosphate
Diethylphosphate
Diethylthiophosphate
Diethyldithiophosphate

Organophosphate pesticides: specific metabolites

Malathion dicarboxylic acid (malathion)
Paranitrophenol (methyl parathion)
3,5,6-Trichloro-2-pyridinol (chlorpyrifos)
2-Isopropoxy-4-methyl-6-hydroxypyrimidine (diazinon)
2-(diethylamino)-6-methylpyrimidin-4-ol/one
3-chloro-7-hydroxy-4-methyl-2H-chromen-2-one/ol

Organochlorine pesticides

Hexachlorobenzene
Beta-hexachloro-cyclohexane
Gamma-hexachloro-cyclohexane (lindane)
P,p-DDE
o,p-DDT
Oxychlordane
Trans-nonachlor
Heptachlor epoxide
Mirex
Pentachlorophenol
2,3,5-Trichlorophenol (not available on PAN database)
2,4,6-Trichlorophenol
Aldrin
Dieldrin
Endrin

Pyrethroid pesticides

4-Fluoro-3-phenoxybenzoic acid
Cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane
carboxylic acid
Trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane
carboxylic acid
Cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane
carboxylic acid
3-Phenoxybenzoic acid

Carbamate Insecticides

1-Naphthol (carbaryl)
2-Isopropoxyphenol (propoxur)
Carbofuranphenol (carbofuran)

Pest Repellants

2-Naphthol
2,5-Dichlorophenol (not available on PAN database)
DEET

Fungicides

O-phenylphenol

Herbicides

2,4,5-Trichlorophenoxyacetic acid (2,4,5-T)
2,4-Dichlorophenoxyacetic acid (2,4-D)
2,4-Dichlorophenol
Atrazine mercapturate (atrazine)
Alachlor mercapturate (alachlor)
Metolachlor mercapturate

Other Pesticides

N,N-diethyl-3-methylbenzamide
ortho-Phenylphenol

Where can I find out more?

About pesticides

Pesticide Action Network North America (PANNA) - http://www.panna.org
PAN Pesticide Database - http://www.pesticideinfo.org
Pesticide Action Network International - http://www.pan-international.org
Pesticide Education Center - http://www.pesticides.org/educmaterials.html

About alternatives

PANNA's Pesticide Advisor - http://www.panna.org/resources/advisor.dv.html
Organic Farming Research Foundation - http://www.ofrf.org

About chemical body burden

Body Burden Working Group - http://www.chemicalbodyburden.org
Natural Resources Defense Council on chemicals in breastmilk - http://www.nrdc.org/breastmilk
Environmental Working Group - http://www.ewg.org
Physicians for Social Responsibility - http://www.envirohealthaction.org/bearingtheburden
Sandra Steingraber - http://www.steingraber.com

About health effects of pesticides

Our Stolen Future - http://www.ourstolenfuture.org
Collaborative on Health and the Environment (CHE)- http://www.cheforhealth.org
CHE science page - http://www.protectingourhealth.org
Physicians for Social Responsibility - http://www.psrla.org/pesthealthmain.htm