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Concerns raised about pesticides' effects
A recent report linking pesticides to cognitive and behavioral problems in children
(see related article, Crime Times, 1998, Vol. 4, No. 3, Page 1 & 4)
supports the concerns of researcher and Crime Times board member, Bernard Weiss.
"Pesticides are chemicals deliberately designed to sabotage biological mechanisms," Weiss notes in a recent paper, "and insecticides are powerful neurotoxicants. Some have achieved total global distribution in human tissues." Yet information about these chemicals' long-term effects, he charges, is "astonishingly primitive."
According to Weiss, the current body of research, although small, strongly suggests that pesticides can have deleterious effects on the brain. Among the studies he cites:
- When British farmers exposed to organophosphate pesticides were compared to controls, the farmers "showed depressed performance on tests of sustained attention and information processing and a greater tendency to psychiatric disorders."
- 100 workers exposed to high levels of organophosphates a single time showed lingering psychological deficits a year later.
- Adult offspring of mice exposed to the organophosphate chemical diazinon during pregnancy showed impaired endurance and coordination, and offspring of the mice exposed to high doses also showed deficits in maze learning. Histological examination of the heavily exposed mice revealed forebrain abnormalities.
- Exposure to high levels of organochlorine compounds (whose use is now strictly curtailed in the U.S.) can cause symptoms ranging from seizures to hyperexcitability.
- One study found that children with a history of acute organochlorine poisoning exhibited "a residue of significant problems, such as reduced IQ scores and troublesome behaviors."
- A Brazilian study linked high levels of organochlorine pesticides to pre-term birth, a risk factor for later behavioral problems.
- Exposure to chlordane, a now-banned organochlorine pesticide, has been shown to cause long-term cognitive problems and mood disorders.
Weiss notes that many organochlorine compounds are "endocrine disruptors,"
chemicals which can alter levels of endocrine hormones or otherwise interfere with the functions of the endocrine system. He points out that developmental endocrine disorders often cause behavioral or intellectual problems.
According to Weiss, as many as 45,000 pesticide poisonings occur every year in the United States, and "the EPA estimates that over 100,000 children directly ingest pesticides each year." Moreover, he says, the wide-scale use of many pesticides such as chlordane "has translated into universal exposure."
Given that these chemicals are known neurotoxins, he concludes, "our knowledge of how these chemicals might modify the course of brain development is disturbingly sparse."
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"Pesticides as a source of developmental disabilities," Bernard Weiss, Mental Retardation and Developmental Disabilities Research Reviews, Vol. 3, 1997, pp. 246-256. Address: Bernard Weiss, Department of Environmental Medicine, University of Rochester Medical Center, Rochester, NY 14642.
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