There are several types of pesticides, which vary according to the pest to be fought. To get an idea of the size of the arsenal, there are around 900 active ingredients in more than 4,000 different formulations. As a safety measure, Brazil – and most countries – have a whole legislation determining the amount to be applied, the time to wait to harvest the food, and the type of product to be used. “Each region has different climatic conditions and, consequently, the species of pests also vary. That is what determines the type of pesticide used in the plantation, which is why it is not possible to relate each pesticide to a specific food group”, says chemist Félix Reyes, from the State University of Campinas (Unicamp). Normally, if the application norms are strictly followed, these products – despite being highly poisonous – leave only chemical residues in the food that are considered “toxicologically acceptable” – that is, they are not harmful to health.
“The greatest risk of poisoning is, in fact, for those who handle and apply the product in the plantations. There are also cases where stallholders use pesticides on their own so that their products remain in good condition for longer,” says Maria Cecília de Figueiredo Toledo, food engineer at Unicamp. “It is good to remember that the penetration of pesticides is limited to the external part of the fruit or leaf. Therefore, a good washing under running water of the food we eat raw can remove most of the poison, making it non-harmful”, says toxicologist Antony Wong, from the University of São Paulo (USP).
There are three types of pesticides that are most harmful to our body
INSECTICIDES (fighting insects)
Organochlorines • Very dangerous
Banned since 1985, these products leave permanent residues in the fatty tissues of mammals, fish and birds. Whoever eats the meat of one of these contaminated animals will be equally affected. The poison also remains in the environment for over 100 years.
Organophosphates • Less dangerous
After poisoning, the effects of these pesticides manifest themselves within 24 hours. They are part of the family of so-called inhibitors and, in addition to physiological effects, they can also cause schizophrenic reactions.
Carbamates • Not very dangerous
While the effects of organophosphates take a month to wear off, those of carbamates only take a week. Both have the same characteristics and are part of the inhibitor family.
HERBICIDES (fighting weeds)
Paraquat • Very dangerous
Extremely toxic, this type of product seriously attacks all body tissues. Intoxication can occur by inhalation or ingestion. If accidentally consumed in its pure state, a single teaspoon is enough to kill.
Glyphosate • Less hazardous
This class of pesticides has relatively low toxicity for humans, but accidental ingestion causes nausea, vomiting and other gastrointestinal disturbances.
Chlorophenoxics • Slightly dangerous
If handled correctly, the pesticides in this group are very non-toxic. However, in its manufacture a substance called dioxin is released, which must be kept separate. If it contaminates the herbicide, the mixture becomes carcinogenic.
RODENTICIDES (fight rodents)
Sodium Fluoracetate • Very dangerous
The rodenticide category is the most poisonous of all, and this particular product is one of the most toxic among them. Its use is prohibited in Brazil, but in other places – such as New Zealand, the United States and Europe – it remains free.
Phosphate • Less hazardous
This product is used to protect seeds in storage before planting. Domestic use against rats is still common in Brazil, despite phosphide being prohibited. When mixed with water or saliva, it releases phosphine, a very poisonous gas.
Hydroxycoumarinics • Little dangerous
Because they are granulated, these products hardly go unnoticed to the point of being ingested by accident. In humans, their toxicity is relatively low, but they can cause bleeding.
Pesticides are extremely dangerous – but only when ingested or inhaled in their pure state
BY AIR
Most liquid pesticides are usually sprayed from airplanes. This method of application becomes especially dangerous on very windy days, as the poison can spread and contaminate rivers and neighboring populations.
CIRCULATORY SYSTEM
Pesticides from the hydroxycoumarinic group make the blood lose its clotting property, which can cause bleeding.
REPRODUCTIVE SYSTEM
Organochlorines, organophosphates and carbamates can cause miscarriage. Chlorophenoxys interfere with sperm production
HEART
Agricultural pesticides from the group of organophosphates and carbamates cause nervous breakdowns that can even cause cardiac arrest. Paraquat burns and damages internal tissues, including the heart.
Liver
Another organ attacked by paraquat, a poison that causes great damage to all internal tissues
DIGESTIVE SYSTEM
Glyphosate, carbamates, organophosphates, and chlorophenoxys also cause vomiting, nausea, and diarrhea. So far, nothing unusual: these are the most common symptoms and the first to appear when there is any intoxication.
BRAIN
Organophosphates and carbamates paralyze essential enzymes in our nervous system. This causes such an out-of-control that it can cause fatal respiratory or cardiac arrest.
ESOPHAGUS
If inhaled, paraquat burns the walls of this communication channel between the pharynx and the stomach, to the point of corroding its tissues
MUSCLES
Organochlorines and chlorophenoxys cause muscle weakness and pain
LUNG
A victim of various pesticides – from paraquat to organophosphates, carbamates and sodium fluoracetate. They all increase pulmonary secretion, causing respiratory arrest. Phosphate can cause respiratory arrest and even death by suffocation.
KIDNEYS
As paraquat causes severe damage to all internal tissues, the kidneys are also severely damaged.
FAT
Organochlorines are lodged in adipose tissues and may, in the long term, develop diseases such as cancer