Top 5 pesticides found in food and health risks

October 24, 2007

1. DDT (organochlorine) First used as an insecticide in 1939. Once the most commonly used pesticide. Banned in 1972 in the United States because it persists in the environment. Still used abroad (.0001–.031 parts per million found in the samples). Used on stored grain since 1985. Most applications have been voluntarily canceled. Moderately persistent in the soil (.0001–.537 ppm). Found in 21% of samples taken.

Even though DDT has been banned since 1972, it can take more than 15 years to break down in our environment. Fish consumption advisories are in effect for DDT in many waterways including the Great Lakes ecosystem. 

What harmful effects can DDT have on us?

  • Probable human carcinogen
  • Damages the liver
  • Temporarily damages the nervous system
  • Reduces reproductive success
  • Can cause liver cancer
  • Damages reproductive system

How are we exposed to DDT?

  • By eating contaminated fish and shellfish
  • Infants may be exposed through breast milk
  • By eating imported food directly exposed to DDT
  • By eating crops grown in contaminated soil

2. Chlorpyrifos-methyl. Chlorpyrifos-methyl is a general use organophosphate insecticide registered in 1985 for use on stored grain (for protection of stored food, feed oil, and seed grains against injury from stored grain weevils, moths, borers, beetles and mealworms including granary weevil, rice weevil, red flour beetle, confused flour beetle, saw-toothed grain beetle, Indian meal moth, and Angoumois grain moth, lessor grain borers), seed treatment, grain bin and warehouse. Chlorpyrifos-methyl can cause cholinesterase inhibition in humans; that is, it can overstimulate the nervous system causing nausea, dizziness, confusion, and at very high exposures (e.g., accidents or major spills), respiratory paralysis and death. In addition, systemic toxicity may include body weight loss, decreased food consumption, liver, kidney and adrenal pathology. Chlorpyrifos-methyl was found in 17% of samples taken.

3. Malathion (organophosphate) One of the earliest organophosphates—introduced in 1950. Low persistence in the soil (.0007–.080 ppm). Found in 15% of samples taken. Malathion interferes with the normal function of the nervous system. Because the nervous system controls many other organs, malathion indirectly can affect many additional organs and functions. Exposure to high amounts of malathion in the air, water, or food may cause difficulty breathing, chest tightness, vomiting, cramps, diarrhea, watery eyes, blurred vision, salivation, sweating, headaches, dizziness, loss of consciousness, and death. If persons who are exposed accidentally or intentionally to high amounts of malathion are rapidly given appropriate treatment, there may be no long-term harmful effects. If people are exposed to levels of malathion below those that affect the function of the nervous system, few or no health problems seem to occur. This has been shown in studies with volunteers who inhaled or swallowed small known amounts of malathion. There is no evidence that malathion affects the ability of humans to reproduce. There is also no conclusive proof that malathion causes cancer in humans, although some studies have found increased incidence of some cancers in people who are regularly exposed to pesticides, such as farmers and pesticide applicators.

4. Endosulfan (organochlorine) Introduced in 1954. Recently limited to agricultural and commercial uses. Moderately persistent in the soil (.0001–.266ppm). Found in 14% of samples taken. Endosulfan generally has been shown to have high acute oral and inhalation toxicity as well as slightly toxic dermal toxicity. It is an irritant to the eyes and is not a dermal sensitizer. Endosulfan is neither mutagenic nor carcinogenic. Endosulfan primarily affects the nervous system. Toxic effects observed in animals from acute, subchronic, developmental neurotoxicity, and chronic/carcinogenic toxicity studies found that endosulfan causes neurotoxic effects, which are believed to result from over-stimulation of the central nervous system. Further, there is evidence (effects observed in a submitted chronic oral toxicity study in rats) that endosulfan acts as an endocrine disruptor.

5. Dieldrin (organochlorine) Second only to DDT in use between 1950 and 1970. Banned in the United States for crop use in 1974 (.0001–.020 ppm). Found in 11% of samples taken.

People who intentionally or accidentally ingested large amounts of aldrin or dieldrin suffered convulsions and some died. Health effects may also occur after a longer period of exposure to smaller amounts because these chemicals build up in the body. Some workers exposed to moderate levels in the air for a long time had headaches, dizziness, irritability, vomiting, and uncontrolled muscle movements. Workers removed from the source of exposure rapidly recovered from most of these effects. Animals exposed to high amounts of aldrin or dieldrin also had nervous system effects. In animals, oral exposure to lower levels for a long period also affected the liver and decreased their ability to fight infections. We do not know whether aldrin or dieldrin affect the ability of people to fight disease. Studies in animals have given conflicting results about whether aldrin and dieldrin affect reproduction in male animals and whether these chemicals may damage the sperm. We do not know whether aldrin or dieldrin affect reproduction in humans.

*Carbaryl was found in 14% of all baby food samples taken. Carbaryl is a wide-spectrum carbamate insecticide which controls over 100 species of insects on citrus, fruit, cotton, forests, lawns, nuts, ornamentals, shade trees, and other crops, as well as on poultry, livestock and pets. Carbaryl is moderately to very toxic, and is labeled with a WARNING signal word. It can produce adverse effects in humans by skin contact, inhalation or ingestion.


*Source: FDA Total Diet Study:

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