Man-made chemical substances backfiring and threatening our well-being – now that’s the kind of irony we’re increasingly getting used to! Pesticides figure prominently in this category. While pesticides help to increase agricultural yield and protect crops from harmful plants, insects, or animals, the fallout of these chemicals among humans is a cause for concern.
A Vicious Cycle
Each year, around one billion pounds of pesticides are used across farms, forests, and lawns in the US.1 Around 17,000 pesticide products are in use right now2 and take the guise of insecticides, fungicides, and fumicides.
Research reveals that only 0.1% of pesticides applied reach the target ‒ the other 99.9% impacts the environment.3 Pesticides can lead to loss of biodiversity, cause soil and water pollution, and trigger chemical resistance in pests. Farmers are often trapped in a pesticide snare, compelled to keep increasing dosage to meet the challenges of chemical-resistant pests. Pesticide residues are widely found in animal feeds too ‒ 80% of corn and 22% of wheat produced in the US each year find their way into animal feed.4
The cascade effect on human beings is inevitable. According to the Environmental Protection Agency, around 10,000 to 20,000 cases of pesticide poisoning (physician-diagnosed cases) are reported each year among 2 million US agricultural workers.5 As per studies by the Centers for Disease Control and Prevention (CDC), all of us carry residual pesticides in our body.6 Apart from people directly dealing with pesticide application, like farmers and factory workers, consumers are exposed to pesticide residues found in food and water. The herbicide atrazine, for instance, was found in 94% of drinking water tested by the United States Department of Agriculture (USDA). Pesticide residues in animal feeds make their way into meat and dairy products as well.
Impact Of Pesticides On Human Health
Pesticides have proven links to endocrine health disruptions, birth defects, liver damage, toxic hepatitis, reproductive issues, and neurological disorders. Children are especially prone to health hazards due to pesticides. It can affect their cognitive development and disrupt the immune, endocrine, and reproductive systems. Pesticides are also known to cause certain types of cancers.7
Impact On The Brain Specifically?
Biochemical alterations have been recorded in the brains of people exposed to pesticides.8 Researchers also reported an impact on the central nervous system (CNS) wherein people with chronic exposure reported episodes of headaches, dizziness, and visual disturbances. Many of the psychotic symptoms were found to be unresponsive to drugs such as levodopa. While both direct and indirect exposure has detrimental effects on the brain and nervous system, it was found that direct exposure through inhaling sprayed pesticides or consumption of food containing pesticide residues had the maximum impact. There was also evidence of neurologic symptoms and neurobehavioral issues in people exposed to pesticides.9
Neurotoxic Effects Of Pesticides Can Take Different Forms
- Cognitive dysfunctions: learning difficulties, slow comprehension
- Psychomotor dysfunctions: issues with attention, emotion, and control
- Memory issues: confusion and chronic forgetfulness
- Anxiety and depression
- Chronic fatigue
- Peripheral neuropathy: damage to the nerves in the extremities like feet
- Dystonia: loss of muscle tone, leading to flabby, loose flesh
- Facial paralysis
- Psychotic symptoms
- Neurodegenerative disorders like Parkinson’s disease
Behavioral studies in animals like rats and guinea pigs also indicated the presence of neurotoxic symptoms in rodents with chronic pesticide exposure. The rodents displayed delayed learning, aggressiveness, insomnia, and hyperactivity.10 Neuronal degeneration was another significant symptom.
Developmental toxicity in fetuses is also another concern with chronic pesticide exposure, especially related to organophosphate chlorpyrifos. Rauh et al. studied the prenatal exposure to this pesticide and found an increased risk of mid-childhood tremors (neurodevelopmental deficits) in children with mothers who had some degree of exposure.11 In another study, researchers found morphological brain anomalies in children with prenatal exposure.12 The organophosphate class of pesticides was detectable in the amniotic fluid and crossed over to the placenta. The researchers found the following symptoms in prenatally exposed children.
- Lower birth weight
- Abnormal neonatal reflexes
- Attention deficits
- Neurodevelopmental disorders like pervasive development disorder (PDD)
There is still some controversy regarding the impact of chronic but moderate exposure to pesticides. Further studies should help settle these. But the need to protect oneself as much as possible from pesticides, whether or not it is handled directly, is indisputable. People involved in pesticide application and spraying must use protective clothing, gloves, and face masks. They must refrain from touching the chemicals directly and must always take a bath after handling these.13
As a consumer too, we need to be aware of pesticide usage in fruits, vegetables, meat, and other products. Wash all produce thoroughly, and in warm salt water. Opt for organically grown fruits and vegetables and free-range or organic meat to reduce exposure. Pregnant or nursing mothers must try and stay away from spaces where pesticides are sprayed.
Pesticide use has sadly become ubiquitous in our world, but small precautions can go a long way toward minimizing exposure.
|↑1, ↑2, ↑5||Pesticide Illness and Injury Surveillance, Centers for Disease Control and Prevention.|
|↑3||Rose, John, ed. Environmental toxicology. Vol. 7. CRC Press.|
|↑4, ↑7||Pesticides, GRACE Communication Foundation.|
|↑6||Pesticides 101, Pesticide Action Network.|
|↑8, ↑9, ↑10||Binukumar, B. K., and Kiran Dip Gill. “Chronic exposure to pesticides-neurological, neurobehavioral and molecular targets of neurotoxicity.” Pesticides in the modern world-Effects of pesticides exposure (2011): 3-20.|
|↑11||Rauh, Virginia A., Frederica P. Perera, Megan K. Horton, Robin M. Whyatt, Ravi Bansal, Xuejun Hao, Jun Liu, Dana Boyd Barr, Theodore A. Slotkin, and Bradley S. Peterson. “Brain anomalies in children exposed prenatally to a common organophosphate pesticide.” Proceedings of the National Academy of Sciences 109, no. 20 (2012): 7871-7876.|
|↑12||Rauh, Virginia A., Wanda E. Garcia, Robin M. Whyatt, Megan K. Horton, Dana B. Barr, and Elan D. Louis. “Prenatal exposure to the organophosphate pesticide chlorpyrifos and childhood tremor.” Neurotoxicology 51 (2015): 80-86.|
|↑13||What You Need to Know about Protecting Yourself When Using Pesticides, PennState Extension.|