- Pesticides are chemicals designed to kill a variety of pests, such as weeds, insects, rodents, and fungi.
- They can be characterized on the basis of function— insecticide (INSECTS), herbicide (PLANTS), rodenticide (RODENTS; RATS AND MICE), fungicide (FUNGI) and others.
HEALTH HAZARDS DUE TO PESTICIDES
The many chemical substances that are collectively referred to as pesticides intervene in different vital metabolic processes in various organisms. The effects of insecticides range from damage to the transmission of nerve impulses and inhibition of blood clotting to paralysis of the respiratory and circulatory centers.
In humans, exposure to pesticides can lead to unspecific adverse health effects that will be referred to here as poisonings. THESE EFFECTS ARE CLASSIFIED INTO 3
1) Acute effects,
2) Delayed effects and;
3) Allergic effects.
- THIS OCCURS WHEN THERE IS A contact with pesticides, AND SYMPTOMS BELOW appear IN a short time after, so that patients or physicians can link them to pesticide exposure.
- Among the typical symptoms of poisoning in humans that are relatively easy to diagnose as acute pesticide poisoning are fatigue, headaches and body aches, skin discomfort, skin rashes, poor concentration, feelings of weakness, circulatory problems, dizziness, nausea, vomiting, excessive sweating, impaired vision, tremors, panic attacks, cramps, etc., and in severe cases coma and death
- Delayed effects are illnesses or injuries that do not appear immediately (within 24 hours) after exposure to a pesticide or combination of pesticides.
- pesticides can also cause chronic illnesses if they are incorporated over a longer period, even if the amounts taken up are relatively small. Symptoms are often diffuse or do not become apparent for a long time, which then leads to late effects. Knowledge about the effects of long-term pesticide exposure is limited to date but numerous late effects are described in the literature.
- Although the Results of various epidemiological studies are inconsistent, these findings leave no doubt that agricultural workers exposed to pesticides have a significant risk of contracting non-Hodgkin lymphomas and leukaemia. Other studies have revealed a correlation between pesticide use and sarcomas, multiple myelomas, cancer of the prostate, pancreas, lungs, ovaries, the breasts, testicles, liver, kidneys, and intestines as well as brain tumors.
Allergic effects are harmful effects that some people develop in reaction to substances that do not cause the same reaction in most other people.
Types of allergic effects –
Some people are sensitized to certain pesticides. After being exposed once or a few times without effect, they develop a severe allergy like response upon later exposures. These allergic effects include:
- Systemic effects, such as asthma or even life-threatening shock,
- Skin irritation, such as rash, blisters, or open sores and;
- Eye and nose irritation, such as itchy, watery eyes and sneezing.
HUMANS ARE HARMED BY PESTICIDES IN TWO WAYS
They may be 1) poisoned or 2) injured.
- Pesticide poisoning is caused by pesticides that harm internal organs or other systems inside the body.
- Pesticide-related injuries usually are caused by pesticides that are external irritants.
TYPES OF EXPOSURE
Pesticides in both wet and dry state can enter our body via
- The skin
- 90% of cases worldwide
- Concentrates penetrates skin more rapidly than water mixtures
- Hands, arms and feet – the most likely contact zones
- Wetable powders, granules or dusts less readily absorbed but sweat enhances skin penetration
- Handling, decanting, mixing concentrates exposes operators to higher risk than actual application
- Degree of hazard depends on dermal toxicity, extent of exposure, amount of body surface exposed, and part of the body exposed (eye versus palm)
- Time lag between exposure and decontamination
2. The respiratory organ
- Through spray droplets or dust. Can cause damage to nose, throat and lung tissues
- Vapours and aerosols with droplet sizes below 10 microns would reach lungs, 50-100 microns impact on the nasal lining.
- Higher risk when working in enclosed spaces, aerosol sprays in green houses, living and bed rooms, or when transferring volatile compound from one container to another
- Product with fumigant action
3. The mouth.
Less common in practice but serious consequences
- Smoking, eating or drinking when mixing pesticides
- Attempt to wipe off sweat from face with contaminated hand
- Clearing spray nozzle by blowing them
- Accidental touching the skin around the mouth when removing respirator or nose mask
- Accidental contamination of foodstuff during transportation
SIGNS AND SYMPTOMS
1) External irritants:
- Redness, blisters, rash, and/or burns on skin and;
- Swelling, a stinging sensation, and/or burns in eyes, nose, mouth, and throat.
2) Pesticide poisoning:
- Excessive sweating, chills, and/or thirsts,
- Chest pains,
- Difficult breathing,
- Cramps in our muscles or aches all over our body.
A secondary line of defense
Protective clothing is as good as
- The way it is used – When an how to wear
- The material it is made of
- The quality of maintenance it gets
The most essential items of protective clothing are :-
- Boots – unlined made of rubber
- Gloves, unlined made of nitrile or neoprene
- Head cover, wide brimmed hat When using UL formulations or when mixing
- Respirator with filters – filters must be exchanged after about 8 hours wear during operation (check with manufacturer’s recommendation)
- Overall : when wearing overall, the trouser legs should be put over the rubber boots to avoid drainage of pesticide into the boots
- Other protective clothing ; Apron, PVC-Coated, nitrile or neoprene material
GENERAL GUIDELINES FOR FIRST AID
1) Pesticide on skin:
- Remove personal protective equipment and contaminated clothing.
- Wash skin and hair thoroughly with a mild liquid detergent and water.
- Dry victim and wrap in blanket or any clean clothing at hand.
2) Pesticide in eye:
- Wash eye quickly but gently.
- Use an eyewash dispenser, if available.
- Rinse eye for 15 minutes or more.
3) Inhaled pesticide:
- Get victim to fresh air immediately.
- Loosen tight clothing on victim that would constrict breathing.
- Apply artificial respiration if breathing has stopped or if the victim’s skin is blue.
4) Pesticide in mouth or swallowed:
- Rinse mouth with plenty of water.
- Give victim large amounts (up to 1 quart) of milk or water to drink.
- Induce vomiting only if instructions to do so are on the labeling.
- All pesticides have the potential to be harmful to humans, animals, other living organisms, and the environment if used incorrectly.
- Modern agriculture practices have been great promise for economic development of nation. Farm productivity is directly proportional to use of agrochemicals as observed from the first green revolution.
- Improper and unsafe use of these agrochemicals, especially pesticides is not only harmful to environment but also human health.
- Poverty and Illiteracy are greatly responsible for improper handling of pesticides.
- However the study has also found that there is ample scope for reducing pesticide exposure through training, agricultural extension and community mobilization etc.
Written by Opeyemi Aduroja