Pesticides and general health effects upon the exposure

According to the EPA (2022), pesticides are substances, or a mixture of substances use for preventing, destroying, or repelling pests and or intended to be use as a plant regulator, defoliant, or desiccant. In other words, A ‘pesticide’ is something that prevents, destroys, or controls a harmful organism or disease, or protects plants and plant products during production, storage and transport.

Due to the increasing world population and high demand for food, there is an increase production and use of pesticides in food production and this has increased human exposure. A person can be exposed to pesticides at home, at school, at work, at sports complexes or even on roads that have been treated with pesticides. Pesticides can get inside body from eating (fruits and vegetables), drinking (contaminated water), breathing them in, and skin contact. Skin contact is the most common form of exposure followed by inhalation and then ingestion. Ingesting pesticides directly usually occurs by accident and is especially done by children. (Qiu L et al, 2021, and Li Z et al, 2022.)

For Pesticides to be effective against their targets, they must be biologically active, or toxic. As a result, pesticides toxicity also has health consequences on humans which could be immediate (eyes irritation, rashes, blisters, blindness, nausea, dizziness, diarrhoea, and death) or long-term consequences (cancers, birth defects, reproductive harm, immunotoxicity, neurological and developmental toxicity, diabetes, Parkinson’s disease, and disruption of the endocrine system). Reproductive harm from pesticides includes birth defects, stillbirth, spontaneous abortion, sterility, and infertility. (Kim, K et al, 2017 and Hu, R et al, 2015.)

Foetal exposure during pregnancy

Maternal exposure (drinking, eating, inhaling, dermal contact) to pesticides during pregnancy increases the risk of foetal exposure. Pesticides can cross the placenta. A placenta is an organ that develops in the uterus during pregnancy, connecting the foetus and the mother in the uterus and tightly regulating the movement of substances between the mother’s blood and the foetal blood. The placenta delivers oxygen, nutrients, and hormones to the developing foetus, while also taking away the waste that the foetus makes.

The term PLACENTA BARRIER is misleading because instead of it providing a barrier (protection) between the mother and the foetus, it instead acts as a route through which substances get to the foetus from the mother. The movement of substances across the placenta is simply by passive diffusion, driven by the concentration gradients between the maternal and the foetal compartment. Also, the placenta is composed of lipids thereby making lipid soluble pesticides easier to cross to the foetus. The presence of the umbilical cord also causes the movement of pesticides from the mother to the foetus. (Karel et al, 2017.)

Why foetuses are more at risk after  exposure

Due to rapid cell division and immaturity in formed organs, foetuses are at the greatest risk of pesticide toxicity. The foetus is most vulnerable during the first 12 weeks due to the differences in the thickness of the placenta membrane. (Weerakkody  Y et al, 2022.)   During this period, all the major organs and body systems are forming and can be damaged if the foetus is exposed to pesticides. (The First Trimester | Johns Hopkins Medicine.)

So, unlike adults, foetuses are unable to protect themselves against the harmful effects of pesticides. For instance, the liver of foetuses is not yet fully matured to detoxify pesticides, their kidneys are not yet able to excrete pesticides, and their nervous system is still developing and can easily be affected by pesticides. Also, the blood-brain barrier that protects harmful substances from reaching the brain from the blood is not yet fully develop in foetuses and therefore pesticides can cross the foetal blood-brain barrier and have devastating health effects on the developing foetus. These effects can manifest immediately or during adulthood. (Hu R et al, 2015.)

Some immediate effects can be dead of the foetus, spontaneous abortion, and premature birth. Foetal exposure to teratogenic pesticides can result in feasible disabilities seen during birth such as cleft lips, missing fingers and or toes, deformed ears and nostrils, and abnormal organ function such as heart defects, neural tube defects like severe birth defects involving the brain, spine, or spinal cord. (Isaković et al, 2022) Foetal exposure to carcinogenic pesticides can result in childhood leukaemia (Halldorsson et al, 2021).

It is important to state that foetal exposure to pesticides can cause diseases that show up in adulthood. These could be reproductive health problems, neurological disorders, hormonal imbalances, learning disabilities, and even cancers. Foetal exposure to some pesticides can also cause long-term Parkinson’s disease. When foetuses are exposed to endocrine disrupting pesticides (pesticides that affect the hormonal system), they caused effects on the developing foetuses that are most evident during adulthood. These effects include poor semen quality and reduce male fertility (Costa M. A. 2016). Also, cancer (mostly breast and prostate cancer) is a long-term risk associated with foetal exposure to pesticides(Botsivali M et al, 2019).

Endocrine disruptors have been linked to attention deficit hyperactivity disorder (ADHD), Parkinson’s (D’Amico,R et al, 2022), Alzheimer’s, diabetes, cardiovascular disease, obesity (Darbre, 2017), early puberty, infertility and other reproductive disorders, and childhood and adult cancer (Del Pup L et al, 2015). In one of the largest studies looking at the potential effects of pesticide exposure on still developing foetuses and new-borns, scientists found that exposure to the most used pesticides was linked to a higher risk of autism spectrum disorder (BMJ 2019).

How to measure pesticides toxicity to the developing foetus

There are several methods used to measure pesticide toxicity to the developing foetus. They can be In vivo (Haas J et al., 2012) (the experiment is carried out inside the living organism), ex-vivo (Schneider H et al., 2022) (the experiment takes place outside of the living organism) and in Invitro (Riss TL et al., 2013) (the experiment takes place outside the organism in glass tubes or glass plates). Clinical laboratory studies (Silver, M et al.,2015) (using cord blood or the first faeces of the baby).

What can we do to minimise foetal exposure to pesticides?

It is important for nurses and all health care providers to be knowledgeable about toxic environmental agents in relation to environmental health risk assessment, exposure reduction, and clinical counselling. It will also be beneficial to integrate toxicity and environmental health into nursing training and practice programmes. Nurses give important patient education on health promotion, and are also encouraged to advocate for health care policies that will reduce harmful exposures and protect the health of pregnant individuals and their children. (Turale et al, 2019.)

All pesticides have the potential to be harmful to humans, animals, other living organisms, and the environment if used incorrectly. The key to reducing health hazards when using pesticides is to limit the exposure by wearing Personal Protective Equipment and using a low-toxicity pesticide when available. Reading the label and practising safe work habits will minimize hazards from the use of pesticides. Remember that many birth defects and other health outcomes of toxic exposure are irreversible, so prevention, education, and strengthened regulation are vital. (WHOa, 2020 and WHOb, 2020.)

Lastly, basic hygiene can go a long way to reduce exposure to pesticides.

• Washing hands before eating. 
• Thoroughly wash and scrub all fruits and vegetables under running water.
• Peeling fruits and vegetables. 
• Avoiding exposure to agricultural areas where pesticides are used (EPA, 2022)

In the case of exposure, consulting medical doctor is vital. The exposure time and the concentration of the pesticide are significant factors that help in determining whether the baby’s health was put at risk. (Kim, K et al., 2017.)

Author:

Ngwengeh Catherine Tanue: catherinetanue.ngwengeh@edu.savonia.fi Bachelor Degree Programme in Nursing.

Supervisor:

Leena Koponen, Senior Lecturer, Savonia UAS. leena.koponen@savonia.fi Internationality Business Unit. Bachelor’s Degree Programme in Nursing.

References:

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The First Trimester | Johns Hopkins Medicine

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