What are pesticides?

After all, what are pesticides and how can they affect plants, humans and other living beings?

Applying pesticide

Pesticides emerged in World War II, with the purpose of working as a chemical weapon. With the post-war period, the product started to be used as an agricultural defensive, becoming also known as a pesticide, pesticide or phytosanitary product. In Brazilian legislation, the term used is pesticide, despite attempts to change it.

Since the 1950s, with the so-called "Green Revolution", agricultural production has undergone many changes. The agricultural process was modernized through research on seeds, soil fertilization and the use of machines in the field. All this to boost productivity. A large part of this technology also involved the wide use of pesticides, in order to control pests so as not to have losses in the agricultural process, since pesticides have the function of altering the composition of fauna and flora.

According to Law No. 7,802/89, "agrichemicals are chemical products, intended for use in the production, storage and processing of agricultural products, in pastures, protection of forests, native or implanted, and of other ecosystems and also urban, water and industrial environments, whose purpose is to change the composition of fauna or flora, in order to preserve them from the harmful action of living beings considered harmful, as well as substances and products used as defoliants, desiccants, stimulants and growth inhibitors" . Growth regulators are also considered agricultural defensives.

Types of pesticides:

  • Fungicides (attacks fungi);
  • Herbicides (attacks plants);
  • Insecticides (attack insects);
  • Acaricides (attacks mites);
  • Rodenticides (affect rodents).

There are other types of specific pesticides for different purposes, such as controlling larvae, ants, bacteria and molluscs, among others. They can also be associated with the mode of action (if through contact or ingestion, for example).

The biggest reason for concern with the use (especially the abusive one) of pesticides is the simple fact that they not only affect certain harmful species to a plantation, but also other living beings, such as bees, earthworms, other plants and also humans.

hazards to human health

Most cases of pesticide poisoning are due to the lack of control over the use of these toxic substances and the lack of awareness of the population regarding the risks to human health. According to the World Health Organization (WHO), for every reported case of pesticide poisoning, another 50 are not reported.

Intoxication can occur directly (through direct contact, handling, application, among others) or indirectly (through ingestion of contaminated food or water). The action of pesticides on human health is usually harmful, even fatal.

According to the Hospital Israelita Albert Einstein, intoxication and poisoning are caused by ingestion, aspiration and introduction into the body, accidental or not, of toxic substances of different natures. They can result in serious illness or death within hours if the victim is not rescued in time.

The types of pesticide poisoning are:

acute

When the victim is exposed to high doses of pesticides. Symptoms are almost immediate, or take a few hours to appear, including: headaches, nausea, sweating, cramps, vomiting, diarrhea, eye and skin irritation, difficulty breathing, blurred vision, tremors, cardiac arrhythmias, seizures, coma and death.

Chronicle

When the victim is exposed to lower doses of pesticides for a long period of time (months or years). This type of pesticide poisoning can have serious consequences, such as: paralysis, sterility, abortions, cancer, damage to the development of fetuses, among others.

It is important to point out that non-specific symptoms, such as headaches, dizziness, lack of appetite, nervousness and difficulty sleeping, can be associated with several diseases, and are often the only manifestations of pesticide poisoning, which is why, unfortunately, makes an accurate diagnosis of this type of intoxication rare.

Pesticides in food

Fruits and vegetables that are displayed and available in the markets have a good, attractive "face", but make no mistake: they can hide in their peel a film of pesticide residues used in the fields.

Food samples with pesticide residues

A survey carried out by the National Health Surveillance Agency (Anvisa) found the presence of organophosphates (one of the most common types of pesticides, used as acaricides, fungicides, bactericides and insecticides, among others) in more than half of the food samples observed - being that these compounds can compromise the nervous system and cause cardiorespiratory problems. The study also highlights that chronic non-communicable diseases (those triggered by pesticide contamination) are a major public health problem today.

In 2008, 57 million deaths were declared in the world and (amazingly) 63% of them were due to the actions of pesticides, according to the WHO. Pesticides are also responsible for 45.9% of diseases in the world.

The ideal would be to consume only foods grown with organic fertilizers, which use biological pest control. Are you curious to know how to get food free of pesticides? Check out the articles "What is organic agriculture?" and "Organic Garden: Eight Steps to Making Yours".

Pesticides and the environment

Agricultural pesticides, regardless of the form of use, have great potential to reach the soil and underground water, even more in the presence of wind and rain, which facilitate their arrival, whatever their path, reaching humanity and other living beings.

Most pesticides are bioaccumulative, that is, if an infected animal dies and another feeds on it, it will also be contaminated. This happens because the compound remains in the animal's body after its death, thus causing a greater scope of the problem.

These substances can cause several damages to the environment, as they undergo chemical, physical and biological processes, which lead to the modification of their properties and influence their behavior. Pesticides are classified by color, according to their contamination potential:

toxicological classification

A red band pesticide poses a risk even with little exposure, whether for time or dosage. The green band also carries risk, but especially if exposure to it is for a long time or in high doses. It is important to highlight that the above classification does not say anything about the long-term effects, nor about the relationship between pesticides and the environment.

Pesticides in Brazil

Brazil is the largest consumer of pesticide products in the world. However, in the ranking of pesticides applied per food produced, it ranks sixth. The fact that we are the largest consumer is due to the fact that we still use pesticides that were already banned in 1985 in the European Union, Canada and the United States, because improved seeds were prepared to receive this type of product, for greater and better productivity, due to the lack of rigorous inspection, with products being launched by air (planes) near the sources of rivers, animals and houses, not to mention the lack of awareness among the population. As Brazil is a tropical country, the incidence of pests and diseases is higher than in other countries, which also encourages the large amount of pesticides used in the country.

Anvisa makes available lists of pesticides released for use in Brazil and those prohibited. In 2019, the number of pesticides released for use in Brazil grew alarmingly and an analysis of data by the Ministry of Health indicates that one in every four Brazilian cities consumes water contaminated by pesticides.

Alternatives

The most effective alternative to avoid the risks of pesticides to humans and the environment is to avoid them, or even not to use them. This can be made possible with the adoption of alternative practices, such as polyculture (which inhibits the proliferation of pests and diseases), the removal of weeds, the use of traps and biological controls (such as the insertion of natural pest predators).

Organic agriculture, which aims to bring agricultural production closer to natural ecological processes, does not allow pesticides, other than natural ones. Therefore, it is the best for the health of the farmer and the consumer, and for the environment in general. This practice also promotes savings in water, fuel, financial resources for the producer, among others.



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