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Archive for October 25th, 2008

Pesticides may damage human brain

Posted by feww on October 25, 2008

Pesticides may damage brain growth in fetuses, infants and children

Many pesticides including organophosphates, carbamates, pyrethroids, ethylenebisdithiocarbamates, and chlorophenoxy herbicides may cause neurodevelopmental toxicity: European study

An Excerpt from:

Neurotoxicity of pesticides: a brief review

By Costa LG, Giordano G, Guizzetti M, Vitalone A.
Dept. of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98105, USA.

  • Pesticides are substances widely used to to protect crops against unwanted pests such as insects, weeds, fungi and rodents.
  • Pesticides are not highly selective, and are also toxic to nontarget species, including humans.
  • Many pesticides cause neurotoxicity.
  • Insecticides, which kill insects by targeting their nervous system, have neurotoxic effect in mammals as well. This family of chemicals comprises the
    • organophosphates,
    • carbamates,
    • pyrethroids,
    • organochlorines
    • other compounds.
  • Insecticides interfere with chemical neurotransmission or ion channels, and usually cause reversible neurotoxic effects, that could be lethal.
  • Some herbicides and fungicides have also been shown to possess neurotoxic properties.
  • The effects of pesticides on the nervous system may involve, or may contribute to
    • acute toxicity, as in case of most insecticides,
    • chronic neurodegenerative disorders, most notably Parkinson’s disease.

This brief review highlights some of the main neurotoxic pesticides, their effects, and mechanisms of action. [Modified for ease of reading: FEWW]

Section of neural tissue, showing three Lewy Bodies; protein inclusions characteristic of Parkinson’s Disease and other neurodegenerative disorders. (Source)

Potential developmental neurotoxicity of pesticides used in Europe [and elsewhere in the world].

A report by: Bjorling-Poulsen M, Raun Andersen H, Grandjean P.

Current requirements for safety testing do not include developmental neurotoxicity. The authors therefore undertook a systematic evaluation of published evidence on neurotoxicity of pesticides in current use, with specific emphasis on risks during early development. This report is based on a review of about 200 scientific reports worldwide about the pesticides and brain.

  • Many pesticides that target the nervous system of insect pests may also be neurotoxic to humans because of the similarity in brain biochemistry.
  • Developing brain may be particularly vulnerable to adverse effects of neurotoxic pesticides.
  • Laboratory experimental studies using model compounds suggest that many pesticides currently used in Europe can cause neurodevelopmental toxicity. These include
    • organophosphates,
    • carbamates,
    • pyrethroids,
    • ethylenebisdithiocarbamates, and
    • chlorophenoxy herbicides.
  • Adverse effects on brain development can be severe and irreversible, therefore, prevention should therefore be a public health priority.
  • The occurrence of residues in food and other types of human exposures should be prevented with regard to the pesticide groups that are known to be neurotoxic.
  • For other substances, given their widespread use and the unique vulnerability of the developing brain, the general lack of data on developmental neurotoxicity calls for investment in targeted research.
  • While awaiting more definite evidence, existing uncertainties should be evaluated in regard to the need for precautionary action to protect brain development. [Abstract modified for ease of reading: FEWW]

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