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  • Writer's pictureLilla Schottner

Pesticides and the neurodevelopment of young children.

Updated: Apr 8

This study was conducted for my Environmental health course. University of the District of Columbia. (2018)

Executive Summary

The use of pesticides in the United States, the tropics, and Costa Rica affects the neurodevelopment of young children.

In tropical countries, pesticides are extensively used in monocultures, such as banana and plantain plantations, resulting in elevated environmental exposures to those living nearby (Barraza et al., 2011). Children living on these plantations or nearby face adverse neurobehavioral effects from pesticide exposure.

Problem and Significance

Pesticides are substances that kill or control pests. Four major classes of pesticides exist organophosphate (O.P.), Organocarbamates, Organochlorines, and Pyrethroids.

The effects of O.P.s (insecticides) are used to control a wide range of insects.

A study by Muñoz-Quezada et al. investigated the neurodevelopmental effects of prenatal and early childhood exposure to organophosphate (O.P.) pesticides on children.

Organophosphate poisoning can produce acute and chronic responses.

Farmers use herbicides,( Roundup and several other commercial weed killers.) rodenticides, fungicides, and insecticides to protect their crops.

Farmers use excessive pesticides in tropical climates, specifically Chlorpyrifos, an organophosphate, on banana and plantain plantations. Scientific evidence shows these chemicals can negatively influence the development of children's brains, I.Q., and cognitive behavior. These chemicals also harm groundwater and negatively affect runoffs to rivers and seas, killing fish and sea life. Chlorpyrifos (O.P.)is a broad-spectrum insecticide because it can kill a wide variety of insects, including bees, and is very toxic to birds.

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, such as learning disabilities, developmental delays, emotional and behavioral problems, attention deficit, hyperactivity disorder ( ADHD ), and autism.

A study of 140 children living near these plantations in Costa Rica/Talamanca was done to assess 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 O.P.s 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 O.P. exposure and neurodevelopmental outcomes. The long-term effects of these O.P.s can be devastating to these communities. 

From birth to school age, children's oral and dermal exposure and exposure through inhalation increases. Although the EPA banned Chlorpyrifos for residential use in the US, Chlorpyrifos (O.P.s) -treated bags still cover banana plants and plantains in Costa Rica to control insects (Barraza et al., 2011). Children living and playing on these fields and their exposure to these Chlorpyrifos may impair visual motor coordination, behavior, and color discrimination abilities in both girls and boys.

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

Recent Events

Chlorpyrifos was banned in 2000 in the United States 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 a "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 the U.S., policies allow the use of these harmful chemicals on all farms. Moreover, our policies today do not require families to move away from farms or the proximity where pesticides are used. Actions must be taken to reduce pesticide use on warm tropical regions.

Latest news from EPA, June 8, 2023

"WASHINGTON - Today, the U.S. Environmental Protection Agency (EPA) announced another action to protect public health under the Toxic Substances Control Act (TSCA), proposing a ban on most uses of perchloroethylene (PCE), a chemical known to cause serious health risks such as neurotoxicity and cancer. Today's proposal would protect people from these risks by banning all consumer uses while allowing for many industrial/commercial uses to continue only where strict workplace controls could be implemented, including uses related to national security, aviation, and other critical infrastructure, and the Agency's efforts to combat the climate crisis." (EPA)

Policy Proposal and Conclusion

Future policy initiatives should ban these O.P.s from these plantations and farms. If banning these Ops is unfeasible, workers and their families should relocate more than a mile from these farms.

Other options could be:

- Integrated Pest Management ( IPM) programs for farmers to use resistant plant varieties or to switch to organic pesticide alternatives for pest control.

- Crop rotation, growing several types of crops, and using compost as a natural fertilizer.

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

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


Friis, R. H. (2012). Essentials of environmental health. Jones & Bartlett Learning, Cop.

Muñoz-Quezada, M. T., Lucero, B. A., Barr, D. B., Steenland, K., Levy, K., Ryan, P. B., Iglesias, V., Alvarado, S., Concha, C., Rojas, E., & Vega, C. (2013). Neurodevelopmental effects in children associated with exposure to organophosphate pesticides: A systematic review. NeuroToxicology, 39(PMC3899350), 158–168.

Organic management of vegetable diseases | Vegetable Pathology – Long Island Horticultural Research & Extension Center. (n.d.). Retrieved February 13, 2024, from

Philippe Grandjean. (2015). Only one chance : how environmental pollution impairs brain development - and how to protect the brains of the next generation. Oxford University Press.

Rusnak, P. (2018, August 6). What Growers Need to Know About Biopesticides. Growing Produce.

Schipani, V. (2017, April 27). The Facts on Chlorpyrifos.

van Wendel de Joode, B., Mora, A. M., Lindh, C. H., Hernández-Bonilla, D., Córdoba, L., Wesseling, C., Hoppin, J. A., & Mergler, D. (2016). Pesticide exposure and neurodevelopment in children aged 6–9 years from Talamanca, Costa Rica. Cortex, 85, 137–150.

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