Pesticides are extensively used all over the world to increase food production and control vector-borne diseases and in recent years their use has increased drastically due to over consumption of food and its increasing constantly with increasing population.
Large amounts of these chemicals are released into the environment. Though each pesticide is meant to kill certain pests, however a very large percentage of pesticides reach a destination other than their target, instead, they the air, water, sediments and even end up in our food.
There are Fifty-six pesticides have been classified as carcinogenic to laboratory animals by The International Agency for Research on Cancer (IARC).
Pesticides have been linked with human health hazards, from short-term impacts such as headaches and nausea to chronic impacts like cancer, reproductive harm.
The use of these pesticides decreases the organic quality of the soil. If there is no chemicals in the soil there would be a higher soil quality, and this would allow higher water retention, which is important for plants to grow.
What are pesticides?
Pesticides are chemical substances, basically, an Insecticides (bug killers), herbicides (weed killers), and fungicides (fungus killers) are all pesticides; so are rodenticides and antimicrobials. Pesticides come in spray cans and crop dusters, in household cleaners, hand soaps, and swimming pools.
Insecticides are generally the most acutely (immediately) toxic. Many are designed to attack an insect's brain and nervous system, which can mean they have neurotoxic effects in humans as well. Herbicides are more widely used (Roundup and atrazine are the two most used pesticides in the world) and present chronic risks.
This means ongoing, low-level exposures can increase the risk of diseases or disorders such as cancer, Parkinson’s disease or infertility and other reproductive harms. Fungicides are also used in large amounts; some are more benign, some are not.
Chemicals related to pesticides
Pesticides are also sometimes broken down into chemical classes and modes of action. For example, fumigants are pesticides applied as gases to "sterilize" soil, and systemic work their way through a plant's tissue after being taken up at the root.
Major chemical classes include carbamates, organochlorines, organophosphates (mostly developed 70 or more years ago for chemical warfare) and triazines. Newer classes include pyrethroids and neonicotinoids, synthesized to mimic nature's pest protection.
· Organophosphate:
Most organophosphates are insecticides, they affect the nervous system by disrupting the enzyme that regulates a neurotransmitter.
· Carbamates:
Similar to the organ phosphorus pesticides, the carbamates pesticides also affect the nervous system by disrupting an enzyme that regulates the neurotransmitter. However, the enzyme effects are usually reversible.
· Organochlorines insecticides:
They were commonly used earlier, but now many countries have been removed Organochlorines insecticides from their market due to their health and environmental effects and their persistence (e.g., DDT, chlordane, and toxaphene).
· Pyrethroids:
These are a synthetic version of pyrethrin, a naturally occurring pesticide, found in chrysanthemums (Flower). They were developed in such a way as to maximize their stability in the environment.
· Sulfonylurea herbicides:
The sulfonylureas herbicides have been commercialized for weed control.
.Biopesticides:
The biopesticides are certain types of pesticides derived from such natural materials as animals, plants, bacteria, and certain minerals.
Grouped by Types of Pests which They Kill
- Insecticides – insects
- Herbicides – plants
- Rodenticides – rodents (rats & mice)
- Bactericides – bacteria
- Fungicides – fungi
- Larvicides – larvae
Pesticides can also be considered as:
ü Biodegradable:
ü The biodegradable kind is those which can be broken down by microbes and other living beings into harmless compounds.
ü Persistent:
ü While the persistent ones are those which may take months or years to break down.
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History of pesticides
Pesticides are not recent inventions! Many ancient civilizations used pesticides to protect their crops from insects and pests. Ancient Sumerians used elemental sulfur to protect their crops from insects. Whereas, medieval farmers experimented with chemicals using arsenic, lead to common crops.
The Chinese used arsenic and mercury compounds to control body lice and other pests. While, the Greeks and Romans used oil, ash, sulfur, and other materials to protect themselves, their livestock, and their crops from various pests.
Meanwhile, in the nineteenth century, researchers focused more on natural techniques involving compounds made with the roots of tropical vegetables and chrysanthemums. In 1939, Dichloro-Diphenyl-Trichloroethane (DDT) was discovered, which has become extremely effective and rapidly used as the insecticide in the world. However, twenty years later, due to biological effects and human safety, DDT has been banned in almost 86 countries.
Global impact of using pesticides
According to the World Health Organization, Pesticides are among the leading causes of death by self-poisoning, in particular in low- and middle-income countries.
The most at-risk population are people who are directly exposed to pesticides. This includes agricultural workers who apply pesticides, and other people in the immediate area during and right after pesticides are spread.
The general population – who are not in the area where pesticides are used – is exposed to significantly lower levels of pesticide residues through food and water.
The United Nations Population Division estimates that, by the year 2050, there will be 9.7 billion people on Earth – around 30% more people than in 2017. Nearly all of this population growth will occur in developing countries.
The Food and Agriculture Organization of the United Nations (FAO) estimates that, in developing countries, 80% of the necessary increases in food production keep pace with population growth are projected to come from increases in yields and the number of times per year crops can be grown on the same land. Only 20% of new food production is expected to come from the expansion of farming land.
Conclusion
As they are intrinsically toxic and deliberately spread in the environment, the production, distribution, and use of pesticides require strict regulation and control. Regular monitoring of residues in food and the environment is also required.
Nobody should be exposed to unsafe amounts of pesticides.
People spreading pesticides on crops, in homes, or in gardens should be adequately protected. People not directly involved in the spread of pesticides should stay away from the area during and just after a spread.
Food that is sold or donated (such as food aid) should comply with pesticide regulations, in particular with maximum residue limits. People who grow their own food should, when using pesticides, follow instructions for use and protect themselves by wearing gloves and face masks as necessary.
Consumers can further limit their intake of pesticide residues by peeling or washing fruit and vegetables, which also reduces other foodborne hazards, such as harmful bacteria.
Pesticides can prevent large crop losses and will, therefore, continue to play a role in agriculture. However, the effects on humans and the environment of exposure to pesticides are a continuing concern.
The use of pesticides to produce food, both to feed local populations and for export, should comply with good agricultural practices regardless of the economic status of a country. Farmers should limit the amount of pesticide used to the minimum necessary to protect their crops.
It is also possible, under certain circumstances, to produce food without the use of pesticides.
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