12
Mar
Pesticide Exposure Again Linked to Neurotoxic Effects in Humans and Wildlife in Comprehensive Review
(Beyond Pesticides, March 12, 2026) The science connecting pesticide exposure to neurotoxicity continues to mount. A study in Discover Toxicology highlights neurotoxic pollutants as significant environmental threats, showcasing the adverse impacts on vertebrates’ neurological health from pesticides, including organophosphates, carbamates, and organochlorines. “These substances disrupt normal neurophysiological functions by impairing neurotransmission, generating oxidative stress, provoking neuroinflammation, and initiating neuronal cell death,†the authors say. They continue, “Such disturbances are linked to cognitive deficits, motor impairments, and abnormal neural development.â€
Neurological conditions can manifest as headaches, muscle weakness, tremors, paralysis, coordination challenges, vision loss, hallucinations, vertigo, seizures, memory loss, slurred speech, trouble breathing with minimal exertion, and more. The range of adverse effects from low-dose, long-term exposure and low-dose (or subchronic) exposure during developmental phases of life raises serious questions about the adequacy of the regulatory review of pesticides, which focuses on acute high and lethal dose exposure. One study on the neurotoxicity of pesticides, published in Chemosphere, concludes, “New regulatory and preventive measures to mitigate the neurotoxic effects of pesticides are needed.†(See also Daily News.)
Even at low concentration, chronic exposure to pesticides and other environmental contaminants “poses serious ecological and health concerns†that occur as these chemicals “bioaccumulate in organisms and biomagnify through food chains, ultimately threatening biodiversity and ecosystem balance.†(See Daily News coverage here and here.) This review captures scientific literature that documents the proposed mechanisms of neurotoxicity from exposure to pesticides and other toxicants, threatening vertebrate neurophysiology.
Importance and Background
Contaminants that specifically target the nervous system cause damage to nerve cells, disrupting neural functions. These toxicants can “interfere with neurotransmission, block nerve impulses, or induce cellular degeneration, leading to severe physiological consequences.†According to the World Health Organization (WHO), over one in three people are affected by neurological conditions, the leading cause of illness and disability worldwide.
As the current review points out, “the prevalence of autism has tripled between 2000 and 2016, coinciding with a more than 15-fold increase in chemical production since the 1940s, including neurotoxicants… Recent data indicate that the prevalence of autism continues to rise, with the CDC [Centers for Disease Control and Prevention] reporting 1 in 36 children diagnosed with ASD [autism spectrum disorder] in 2020, coinciding with sustained high levels of industrial chemical production.†The researchers continue, saying, “Additionally, exposure to agricultural chemicals such as glyphosate has increased markedly, with usage rising to about 250 million pounds per year in the United States and animal models linking glyphosate to oxidative stress and depressive-like behaviours such as reduced mobility in the forced swim test and increased immobility time, which are indicative of behavioural despair and altered neurochemical signaling.â€
When chemicals impair neuronal signaling, it can lead to symptoms such as paralysis and convulsions. The nervous system plays a crucial role in animal physiology, as “even subtle biochemical disruptions in specific neuronal populations can significantly alter behaviour.†Specifically, some pesticides, namely organophosphates, carbamates, and organochlorines, act by inhibiting acetylcholinesterase (AChE), an enzyme essential for neurotransmission, which can lead to “prolonged neuronal excitation and potential neurotoxicity.†(See study here.)
As many environmental pollutants have been connected to neurotoxic symptoms, this is a public health concern. “There is growing evidence from human epidemiological studies that environmental pollutants cause neuroinflammation, oxidative stress, endoplasmic reticulum stress, mitochondrial dysfunction, myelin sheath disruption, and alterations in the BBB [blood-brain barrier] anatomy that lead to cognitive dysfunction and reduced quality of life,†the authors state. “These environmental contaminants also significantly lower IQ, have teratogenic effects [causing birth defects/malformations], cause developmental neurotoxicity, and cause mental growth retardation.†(See here and here.)
What the Science Shows
Neurotransmission and brain development are impacted by various pesticides, as documented in many different organisms. “Environmental neurotoxicants have been linked to measurable population declines and biodiversity loss in various vertebrate groups,†the researchers write. Below is evidence of these impacts:
Amphibians
Behavioral abnormalities, neurodevelopmental deficits, and population decreases are seen in amphibian populations with pesticide exposure. As the review points out: “In amphibians, chronic pesticide exposure, particularly organophosphates and carbamates, has led to widespread neuromuscular dysfunction, predator evasion failure, and larval mortality, contributing to regional declines of species like the northern leopard frog (Lithobates pipiens). [The h]erbicide atrazine, through endocrine disruption and neurodevelopmental interference, contributed to amphibian population crashes and altered sex ratios in wild populations.†(See here.)
The insecticide carbaryl also causes serious harm to amphibians by interfering with their immune and neurological systems. In addition, tadpole immunosuppression, oxidative stress, and developmental defects are linked to long-term exposure to low concentrations of carbaryl. (See studies here and here.)
Reptiles
Pesticides, particularly organophosphates, have “a major negative impact on reptiles’ behaviour, neuromuscular coordination, and ability to survive,†which jeopardizes “population viability by impairing eating, predator evasion, and reproductive activities.†(See research here.) Among the range of effects, including neurological, per- and poly-fluoroalkyl substances (PFAS), which are known to bioaccumulate, also threaten aquatic and semi-aquatic species. “The reproductive, endocrine, neurological, cardiovascular, and immunological systems are among the several systems that are impacted by PFASs since they are endocrine disruptors,†the authors note. In one study, wild freshwater turtles (Emydura macquarii macquarii) captured downstream from an industrial PFAS source in Queensland, Australia show changes in their blood, as well as significant bioaccumulation and signs of toxicological stress.
Mammals
In mammals, including humans, pesticide exposure causes deleterious health effects, particularly on the nervous system, directly and indirectly. Direct effects include pesticides interacting with the nervous system and causing damage or disruption to neural function while indirect effects apply to other bodily systems that, in turn, impact the nervous system. “Exposure to neurotoxic chemicals, like pesticides, may be linked to behavioural and cognitive disorders, such as attention-deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and other developmental cognitive impairments, according to research,†the researchers say. They continue: “Many neurotoxic pollutants are also endocrine disruptors, affecting human hormonal systems, which can lead to reproductive and developmental issues. Humans, especially children and pregnant women, are highly susceptible.â€
A wide body of science connects paraquat (PQ) to adverse health effects in humans. As the review highlights: “Human PQ poisoning caused severe systemic inflammation and markedly increased serum pro-inflammatory cytokines… [T]hese preliminary studies of PQ-induced molecular events associated with PD pathophysiology highlight neuroinflammation elements, impaired dopaminergic neurons in the midbrain, disrupted lipid metabolism, and severe systemic inflammation.†In studies of mice (see here and here), PQ also bioaccumulates in the liver, kidneys, and lungs and causes oxidative stress and DNA damage.
Another chemical class with documented effects on human health is pyrethroids. The authors state: “A class of insecticides known as pyrethroids shares structural similarities with natural pyrethrins. Pyrethrins are used in agriculture and pest management, which results in a variety of environmental pollutants that harm human health and a decline in the population of soil microbes that influence soil fertility and health… In addition to producing significant quantities of ROS [reactive oxygen species, essential for cell signaling, homeostasis, and immunity at low levels], pyrethroids are reported to alter the human plasma biochemical profile.†(See here.)
Additional Concerns
This review mentions the “cocktail effect,†which refers to the combined or interactive effects of multiple contaminants that can be additive (total effect equals the sum of each individual effect) or synergistic (total effect is greater than the sum, amplifying toxicity). With this increase in toxicity as multiple pesticides are encountered as mixtures, further health threats occur. “This concept challenges traditional toxicology, which often evaluates substances in isolation,†the researchers note. The scientific literature has long documented the regulatory deficiencies regarding assessing additive and synergistic effects of pesticide mixtures.
For example, exposure to both organophosphates and pyrethroids causes synergistic effects in vertebrates, such as fish and rats. Neurological impairment, as well as increased mortality, is documented, as well as increased oxidative stress and damage to detoxification pathways. “This results in increased neurotoxicity, developmental abnormalities, and impaired motor functions in exposed wildlife [and] emphasizes how regulatory risk evaluations must take into account the cumulative effects of pesticide combinations rather than analyzing them separately.†(See research here and here.)
Previous Research
The science on neurotoxicity is robust. In a Daily News from last year, entitled Behind the Numbers Linking Pesticides to Neurological Disorders, the World’s Largest Source of Disability, a report published by The Lancet on the global burden of nervous system diseases is reviewed, with the connection to pesticide exposure discussed. The Lancet report indicates that disability-adjusted life years (DALYs) from Parkinson’s disease have increased by 10 percent, and autism spectrum disorder and dementia by 2 percent each, all of which have been connected to pesticide exposure. See Beyond Pesticides’ deep archive of the evidence on pesticides and neurological diseases in the Pesticide-Induced Diseases: Brain and Nervous System Disorders section. The Gateway on Pesticide Hazards and Safe Pest Management is an archive of information about specific pesticides and their adverse health effects.
Another Daily News post documents the neurotoxic impacts of neonicotinoids in mammals. A study, published in The Journal of Toxicological Sciences, shows that a single dose of the neonicotinoid insecticide clothianidin induces behavioral abnormalities, predominantly in female mice, throughout key stages of development. In testing mice at various ages, sex-specific changes were identified that highlight not only varied effects on males and females, but also how pesticide exposure at a young age can cause lasting impacts throughout adulthood in mammalian species. Additional studies highlight the neurotoxic effects of pesticides that increase the prevalence of mood disorders and neurodevelopmental damage in children. (See here and here.)
Moving Forward
Exposure to pesticides poses severe risks to wildlife, as well as humans, leading to population declines, reproductive issues, behavioral abnormalities, and more. Protecting all organisms from these deleterious effects requires the widespread elimination of petrochemical pesticides and synthetic fertilizers, as well as the adoption of alternative land management practices that negate the need for harmful pest management methods.
The current study authors conclude by saying: “A One Health approach, emphasizing the interconnectedness of human, animal, and environmental health, is essential for linking ecological neurotoxicity findings, such as those in zebrafish, amphibians, or sentinel species, with human conditions such as autism spectrum disorder and Parkinson’s disease… Such a comprehensive, translational approach is vital to safeguarding neurodevelopment, biodiversity, and long-term ecosystem health from the growing burden of environmental neurotoxicants.†They also identify organic farming practices as able to “help minimize pesticide residues in food, reducing the risk of long-term health effects.â€
Join the organic movement by buying organic products (on a budget!), growing your own organic food, and taking action through Action of the Week, where you can have your voice heard on governmental actions that are harmful to the environment and public and worker health, increase overall pesticide use, or undermine the advancement of organic, sustainable, and regenerative practices and policies. Take Action: >> Tell your U.S. Representative and Senators to become a cosponsor of the Opportunities in Organic Act (S. 3717/H.R. 7318).
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source:
Shaw, R. et al. (2026) Emerging prospects and consequences of environmental neurotoxic pollutants in the vertebrate system, Discover Toxicology. Available at: https://link.springer.com/article/10.1007/s44339-025-00042-w.
