• Lilla Schottner

Pesticides and the neurodevelopment of young children.

Updated: Jan 6

My paper for my Environmental Health Course at the University of the District of Columbia. 2018

Executive Summary

Pesticides/organophosphates (OP) affect the neurodevelopment of young children in the US, the tropics, and specifically in Costa Rica. Various actions must be taken to reduce pesticide exposure to children living on plantations or nearby in order to prevent negative neurobehavioral effects due to these exposures. 

Problem and Significance

Pesticides are substances to kill or control pests. Four major classes of pesticides exist: Organophosphate (OP), Organocarbamates, Organochlorines and Pyrethroids.

The effects of OPs (insecticides) are used to control a wide range of insects.

Many studies have investigated the neurodevelopmental effects of prenatal and early childhood exposure to organophosphate (OP) pesticides among children.

Organophosphates poisoning can produce acute and chronic response.

Farmers use herbicides, rodenticides, fungicides and insecticides to protect their crops.

In the tropical climates, farmers use excessively pesticides, specifically Chlorpyrifus an organophosphate on banana and plantain plantations. There is scientific evidence that these chemicals can negatively influence the developing children’s brain, their IQ and their cognitive behavior. Not to mention the effects of chemicals in ground-water, as well as run-offs to rivers and the sea where fish and sea-life is dying. Chlorpyrifos (OP)is a broad-spectrum insecticide because it can kill a wide variety of insects, including bees and it is very toxic to birds as well.

Children are more vulnerable to these toxicants than adults because their organs are not yet fully developed. Even low levels of exposure can affect young children’s neurological and behavioral development, like for example: learning disabilities, development delays, emotional and behavioral problems, attention deficit, hyperactivity disorder, ADHD and autism (Bjorling- Poulsen et al. 2008). The Swedish Research Council for Environment and Canada’s International Development Research Center conducted a cross sectional study of 140 children living near these plantations in Costa Rica/Talamanca and assessed their neurobehavioral performance. Urinary samples of those living on these plantations or nearby show elevated levels of Chlorpyrifos. A longitudinal study that assessed prenatal exposure to OPs showed that cognitive deficits were found in children at age 7; behavioral and attention deficits were seen in toddlers; abnormal reflexes were seen in newborns. During the prenatal stage, the developing fetus is vulnerable to transplacental and external exposures. The researchers also found that every 100 pounds of Chlorpyrifos applied within a mile (1.5 kilometers) of pregnant mother’s homes increased the chance of their child developing autism disorder by 14 percent. A positive dose-response (the effect of exposure to a chemical or toxic substance) relationship was found between OP exposure and neurodevelopmental outcomes. The long-term effects of these OPs can be devastating to these communities. 

From birth to school age, children’s oral and dermal exposure increases, as well as exposure through inhalation. Although Chlorpyrifos was banned by the US EPAfor residential use, Chlorpyrifos (OPs) -treated bags are still covering banana plants and plantains in Costa Rica in order to control insects. Children living and playing on these fields and their exposure to this Chlorpyrifos may impair visual motor coordination, behavior and color discrimination abilities in both girls and boys.

Weekly aerial spraying of Mancozeb (fungicide) may also affect negatively children’s verbal learning. In pregnant women living nearby, elevated levels of Mancozeb were detected in their thyroidal function.Children also could be exposed to other pesticides like Pyrethroids (control indoor pests, lice, fleas in pets) in their homes.

Neurodevelopmental effects of non-OP pesticides have been hardly studied

(Bjorling- Poulsen et al. 2008).

Recent Events

Chlorpyrifos was banned in 2000 in the US by the EPA for residential use and it was restricted even further between 2000 and 2012. In 2015, under the Obama administration, EPA proposed a complete ban on Chlorpyrifos. In November 2016, the EPA under Scott Pruitt’s direction decided not to ban Chlorpyrifos, stating that the exposure of this chemical to children’s neurodevelopment is “novel, highly complex and unresolved scientific issue”. A Scientific resolution on this matter is said to be completed by 2022. Meanwhile in Costa Rica and in the US, policies allow the use of these harmful chemicals on all of the farms. And our policies today don’t require families to move away from farms or the proximity where pesticides are used.

Policy Proposal /Conclusion

Future policy initiatives should ban these OPs from these plantations and farms. If banning these Ops is unfeasible, workers and their families should be relocated more than a mile away from these farms.

Other options could be:

- Integrated management programs for farmers to use resistant plant varieties or to switch to organic pesticides alternatives for pest control.

- Crop rotation, growing several types of crops or using compost are also good options.

- Biopesticides are natural pesticides obtained from plants, bacteria and other microbes. They pose less harm to the environment and the health of the children and workers than OPs.

- Organic farms are the future, the best way to grow plants without harming farm workers and children living nearby.


Science direct Costa Rica , Talamanca 


Ruckart PZ, Kakolewski K, Bove FJ, Kaye WE. Long-term neurobehavioral health effects of methyl parathion exposure in children in Mississippi and Ohio. Environ Health Perspect. 2004;112:46–51. [PMC free article]  [PubMed]

Grandjean P, Harari R, Barr DB, Debes F. Pesticide exposure and stunting as independent predictors of neurobe-havioral deficits in Ecuadorian school children. Pediatrics. 2006;117(3):e546–e556.  [PubMed]




Book: Enviromental Health, Chapter 7 Pesticides and other organic chemicals




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