Does it ever seem like the population is being “dumbed down”? Maybe that is literally happening — even before birth. And at least one of the culprits appears to be organophosphate pesticides that are widely used on food crops throughout the U.S.
The evidence for the intelligence robbing effect of these poisons isn’t some obscure study in lab animals, either. This is a major discovery involving human children in multiple studies. The results of three separate research papers have just been published in the journal Environmental Health Perspectives and all document this alarming fact: pesticides could be robbing many humans of their maximum intelligence potential.
“These associations are substantial, especially when viewing this at a population-wide level,” said study principal investigator Brenda Eskenazi, UC Berkeley professor of epidemiology and of maternal and child health, in a statement to the media. “That difference could mean, on average, more kids being shifted into the lower end of the spectrum of learning, and more kids needing special services in school.”
This isn’t a problem limited to children living near farms where pesticides are regularly sprayed, either. The other two studies, one conducted by scientists at Mt. Sinai Medical Center and the other by researchers at Columbia University, investigated pesticide exposure in urban populations in New York City.
The Mt. Sinai research involved assessing toddlers at 12 and 24 months of age using standardized testing that measures cognitive and psychomotor development in young children. Then, when the children were between six and nine years old, the researchers administered skill and intelligence tests.
The results? Just as the UC Berkeley researchers found, the Mt. Sinai scientists discovered that exposure to organophosphates negatively impacted perceptual reasoning. In plain English, that means the children did not have the level of nonverbal problem-solving skills that normal, healthy kids are expected to have.
Both the UC Berkeley and Mt. Sinai research teams measured pesticide metabolites in maternal urine; the scientists at Columbia measured umbilical cord blood levels of a specific pesticide, chlorpyrifos. And, it’s important to note, the Columbia study is the first to look at neurotoxicity of chlorpyrifos exposure before birth to see how it impacts cognitive development as children reach school age.
Although it was banned for indoor use in homes by the U.S. Environmental Protection Agency (EPA) in 2001, chlorpyrifos was once an extremely popular organophosphate pesticide for residential use and still lingers in the environment. The Columbia researchers found that the amount of chlorpyrifos in babies’ blood was linked to neurodevelopmental problems by age three and these deficits persisted at least through age seven — with possible long-term educational implications.
What’s more, consider this extremely important finding: the decline in intelligence test scores began at the lowest exposure to the pesticide. The test scores spiraled down more with increasing exposure levels. This suggests, the scientists said in a press statement, there is “..no evidence of a threshold, below which exposures are completely safe.”
“These observed deficits in cognitive functioning at 7 years of age could have implications for school performance,” Virginia Rauh, ScD, deputy director of the Columbia Center for Children’s Environmental Health (CCCEH), and lead author of the Columbia study, said in a statement to the press. “Working memory problems may interfere with reading comprehension, learning and academic achievement, even if general intelligence remains in the normal range.”
Since the EPA ban took effect, exposure to the organophosphate has measurably declined somewhat. However, agricultural use of chlorpyrifos is still permitted in the U.S. and pregnant women, especially in agricultural communities, are still being exposed to this potentially intelligence-zapping chemical.
“Manufacturers withdrew chlorpyrifos and diazinon, two types of organophosphate pesticides, from the residential market. Despite this, general population exposure to organophosphate pesticides is ongoing,” Stephanie Engel, PhD, who led the Mt. Sinai School of Medicine study , explained in the media statement.
For more information:
Bouchard et al., “Prenatal Exposure to Organophosphate Pesticides and IQ in 7-Year-Old Children,” http://ehponline.org/article/info:d….
Engel et al., “Prenatal Exposure to Organophosphates, Paraoxonase 1, and Cognitive Development in Childhood,” http://ehponline.org/article/info:d….
Rauh et al., “7-Year Neurodevelopmental Consequences of Prenatal Exposure to Chlorpyrifos, a Common Organophosphate Pesticide,” http://ehponline.org/article/info:d…