Global chemical contamination serious threat to child development.

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Global chemical contamination serious threat to child development

Concern is growing worldwide over the long-term health effects of chemicals known as persistent organic pollutants (POPs). These pollutants are toxic and they don’t go away. Instead of degrading, they accumulate and remain in the tissue of humans and animals and other ecosystems for a long period. This bio-accumulation of toxic chemicals increases the risk for diseases such as cancer. It also contributes to abnormalities in brain development and in the reproductive systems of animals and human beings.

One reason for the widespread concern is that the effects of POPs on child development may be threatening the talent and intelligence of future generations. Studies show exposure to POPs is shifting the IQ of the population downward – more developmentally-challenged people and fewer gifted people, said Lynn Goldman, MD, MPH, in a recent Baylor College of Medicine Grand Rounds presentation.

POPs can cause endocrine disruption – changes in hormones that can affect brain development and the reproductive system. Goldman gave examples of DDT and DDE two pesticides now ban in the United States but still present in the environment and used in other countries. She cited a study that showed birds exposed to these pesticides became infertile because the hormone for maturation of eggs was blocked. One study of mothers exposed to DDT found that they had a shorter lactation period. Mothers that were not exposed to DDT were able to breast feed their babies seven-and-a-half months while mothers exposed to DDT had a lactation period of only three months. Other studies have found that women exposed to DDE have preterm births.

Goldman also noted that daughters of mothers exposed to DDT and DDE may have fertility problems. One study found that for every 10 milligrams per liter of DDT exposure in the mother, the daughter’s pregnancy probability dropped 32 percent.

Other studies presented by Goldman show developmental delay can be caused by exposure to Polychlorinated byphenols (PCBs), another persistent organic pollutant (POP). A decrease in birth weight and motor development delay in newborns have been linked to mothers’ PCB exposure. Other studies show defects in visual recognition memory and delays in cognitive development related to PCB exposure.

Breast-feeding infants have a high exposure to dioxin, the toxic byproduct of PCBs, according to several studies. Goldman said the greatest risk is for the fetus in the womb, and that breastfeeding is still the best food source for babies.

PCBs are being replaced by polybrominated diphenyl ether (PBDEs). Goldman said studies show this chemical is similar to PCBs in the brains of animal and is not an improvement over PCBs for the environment.

Contamination of the environment with persistent organic pollutants is not contained within a country’s boundaries. “POPs are often transported long distances via air, water and migratory species,” Goldman said.

Global efforts to eliminate POPs have been developing since the early 1990s. The Stockholm Convention on Persistent Organic Pollutants, signed by several nations including the United States in May 2001, calls for the elimination of 12 POPs, including the pesticides aldrin, chlordane, dieldrin, endrin, heptachlor, hexachlorobenzene (HCB), mirex and toxaphene, as well as PCBs. It also calls for restricting use of DDT to disease vector control until safe, affordable and effective alternatives are in place, mandating removal of PCB equipment, and encouraging minimization of unintentional release of dioxins and furans. The treaty has a provision for adding other POPs to the elimination list and for preventing the introduction of new POPs into commerce. It also calls for providing technical and financial assistance to developing countries and countries with economies in transition.

Goldman, who has served in various governmental positions as an expert on the environment and public health, including assistant administrator for Prevention, Pesticides and Toxic Substances at the Environmental Protection Agency (EPA), asked the Grand Rounds audience of physicians, residents and others concerned about POPs to encourage the U.S. government to support the implementation of the Stockholm Convention on POPs.

In testimony, July 2004, urging the U. S. Congress to assume its share of responsibility for assuring global chemical safety she said, “Control of POPs is about protecting our food supply, protecting the fetus and protecting the safety of breast milk for infants. Clearly, POPs are among the substances that are of most concern on a global basis.”

For a transcript of Goldman’s testimony, click here. For more information on the on the Stockholm Convention on Persistent Organic Pollutants (POPs), and a listing and description of POPs, please visit www.oztoxics.org .  ,

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For more information, contact:

Geoffrey Castro, Executive Director or Vicki Wolf, Environmental Writer

Citizens League for Environmental Action Now

Telephone: 713-524-3000

email: info@cleanhouston.org

website: www.cleanhouston.org

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