What Is a Pesticide? Is It Harmful to Health, and Does It Pose a Cancer Risk?

What Is a Pesticide?

Pesticide is an umbrella term covering any agent or technique used to control pests. Here, pests may include insects, fungi, weeds, mollusks and worms that damage people’s food supplies and crops or spread disease. A pesticide may be a chemical substance, a biological agent such as a virus or bacterium, a disinfectant or any other application.

What Types of Pesticides Are There?

They are named according to the types of pests against which they are effective.

• Antimicrobials: against bacteria and viruses,
• Fungicides: against fungi,
• Herbicides: against unwanted weeds,
• Insecticides: against insects and pests,
• Molluscicides: against mollusks,
• Acaricides: against mites, and
• Rodenticides: are pesticides against rodents.

Pesticides are not used only in agriculture; they are also used in homes/buildings to kill insects and control pests. The idea that exposure to pesticides occurs only through agricultural chemicals is therefore incorrect.

The benefits of pesticide use are indisputable, but their potential harms to humans and animals should not be overlooked.

Are the Harms of Pesticides Exaggerated? Where Does Their Bad Reputation Come From?

Arsenic and sulfur were the first substances used as pesticides. Plant-derived substances, such as pyrethrum obtained from chrysanthemums, later came into use. In the early 20th century, pesticides containing mercury and lead began to be used. In 1939, Swiss chemist Paul Mueller identified the most famous pesticide of all time, DDT, and dichlorodiphenyl trichloroethane entered the market in 1942 and quickly became widespread. During World War 2, research on nerve gases led to the discovery of parathion, an organophosphorus insecticide, which was marketed in 1943... Note that some substances formerly used as pesticides (such as arsenic, mercury, lead and DDT) are toxic and were later found to cause cancer. Pesticides therefore have a very bad reputation. The use of many pesticides used in the past is now banned.

Another interesting fact about pesticides is their prominent role in adult suicide attempts. A study conducted in England in 1994 found that %73 of deaths associated with pesticide use resulted from suicide attempts involving ingestion of pesticides. According to data from poison research and consultation centers in Türkiye, pesticide poisoning (%7-10) ranks second after poisoning with human medicinal products (%65-70).

Which Pesticides Are Commonly Used Today?

The most commonly used organophosphate insecticides in agriculture are chlorpyrifos and acephate, while the most common for home and garden use are carbaryl, acephate and pyrethroids.

Many herbicides are registered worldwide, but the 5 most widely used in agriculture are:

• Glyphosate,
• Atrazine,
• Metolachlor-S,
• 2,4-Dichlorophenoxyacetic (2,4-D) acid and
• the fumigant dichloropropene.

Does Pesticide Use Pose a Cancer Risk?

Population-based epidemiological studies have investigated concerns about the adverse health effects of pesticide exposure and whether there is a relationship between cancer and both occupational and residential use.

Population-based observational data on pesticides, which are widely used worldwide to control pests, suggest that different pesticide types are associated with certain cancers in children and adults. Exposure to pesticides through residences (homes, buildings and residential complexes), particularly during pregnancy, is associated with childhood cancers. Whether pesticides encountered in homes cause adult cancers is unclear.

- Related topic: Insecticides used in homes pose a cancer risk for children

Although pesticide use appears to pose a greater cancer risk for agricultural workers, this varies according to pesticide type, exposure duration, dose and the associated cancer type. Research on cancer risk in agricultural areas with heavy pesticide use is mixed. Some studies show an association in regions with high pesticide consumption, while others find no relationship.

A pesticide frequently used as a weed killer, glyphosate (commonly known by the trade name Roundup), was placed by the World Health Organization in 2017 on the potential carcinogen list.

Summary

Agricultural use is not the only source of pesticide exposure; we are also exposed to pesticides and other chemicals (such as stain removers) in many different ways in homes. The relationship between agricultural pesticide use and cancer is unclear. Nevertheless, agricultural workers and their families in particular are advised to take strict measures to minimize pesticide exposure. As consumers, we should also wash foods thoroughly before eating them. This thorough washing also applies to organic foods as well.

- Related topic: When does a carcinogenic substance cause cancer?