Organochlorine Pesticides
Trade Secrets
Examples: DDT, Methoxychlor


Known Health Effects: Endocrine disrupter. Nausea, vomiting, headaches, dizziness, abdominal pain, diarrhea, confusion, a sense of apprehension, weakness, loss of muscle control, and tremors. Higher exposures can damage the nervous system.

Suspected Health Effects: Lung, liver, thyroid, lymphatic system cancer. Developmental and reproductive toxicity. Chronic effects on liver, kidneys, immune and nervous systems. Damaged chromosomes in men occupationally exposed.

Known Health Effects: Endocrine disrupter. Anxiety, dizziness, headache, confusion, muscle twitching and tremor. Higher levels can damage the nervous system.

Suspected Health Effects: Reproductive toxicity. Liver and kidney damage, lowered testosterone production. Damage to testes and ovaries, and lowered fertility in people born to exposed mothers.

Ten different organochlorine pesticides turned up among the people in the Mount Sinai pilot study – including traces of pesticides long banned in this country (BHC, DDT and chlordane). EPA designates a number of these pesticides as persistent, bioaccumulative, and toxic (PBT) because they do not break down in the environment – they persist - and they concentrate as they move up the food chain – or bioaccumulate.

Pesticides like DDT and chlordane - though banned in many countries, including the United States – are still used in Central America, India, China and countries in Africa.

DDT - Bill Moyers tested positive for both DDT and DDE, a common human metabolite of DDT. DDT’s devastating effects on birds and wildlife provided the first clues to the chemical’s persistent, toxic nature. Much of the nation first became aware of the dangers of indiscriminate chemical use after publication of the 1962 book, Silent Spring, in which Rachel Carson powerfully detailed DDT’s role in the near extinction of bald eagles and other birds.

By the time the U.S. banned DDT in 1972, an estimated 1.2 billion pounds had already been sprayed on fields, marshes, fruit trees and in cities nationwide. Almost 30 years after the ban, scientists continue to measure DDT in air, rain, soil, water, animals and plants. It even shows up in studies of house dust. Most human exposure comes from food, particularly meat, fish, poultry, fruit and root and leafy vegetables. Because DDT accumulates in fatty tissues, concentrations in human milk are higher than in cow's milk, according to the U.S. Agency for Toxic Substances and Disease Registry (ATSDR).

Methoxychlor – Methoxychlor is not usually detected in air or water, with only low levels sometimes found in food. Yet, Mount Sinai researchers measured relatively high levels of the pesticide in blood samples from 7 of 9 people in their study, including Bill Moyers.

The pesticide came into favor as a replacement for DDT in the 1970s, and is still in wide use on fruits, vegetables, forage crops and shade trees, and as a parasite dip for dairy and beef cattle. Methoxychlor breaks down far more quickly than DDT and is less overtly toxic. Human volunteers who ate small amounts of the pesticide did not immediately get sick. It does not appear to cause cancer, but studies of laboratory animals have raised concerns that long-term exposure to methoxychlor may present a formidable reproductive risk to humans.

When rats were dosed with methoxychlor, fewer animals mated; of those who did, many did not produce litters. The pesticide arrested sperm production in male rats and damaged the ovaries of females. In a March 2000 study, the Center for Biomedical Research in New York concluded that a methoxychlor metabolite, HPTE, causes declines in testosterone production, and therefore could be “a contributory factor in male infertility” in humans.

Researchers have also measured elevated levels of methoxychlor metabolites in Florida panthers, a now endangered species. Nearly all the males suffer from abnormalities that include undescended testes, low ejaculate volume and low sperm concentrations. Scientists believe these conditions may develop in male cubs because they are exposed to methoxychlor and other endocrine disrupters in the womb. Other researchers have noted similar effects in laboratory animals.

Further reading:

Extoxnet (Cornell University) Fact Sheet

NTP website

pdf - New Jersey Department of Health, Hazardous Substance Fact Sheet

Biology of Reproduction Journal - article on testosterone decline

Full list of sources available via e-mail

Aerial spraying
By the time the U.S. banned DDT in 1972, an estimated 1.2 billion pounds had already been sprayed on fields, marshes, fruit trees and in cities nationwide.

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Photo Credit: ©2001 Corbis