**1. Introduction**

In the last three decades, there has been an increasing global worry over the public health impacts attributed to environmental pollution. It was the industrial revolution that gave birth to environmental pollution as we realize it today. Populations of developing countries are particularly vulnerable to toxic pollution resulting from industrial processes.

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Pollution is the introduction of contaminants into the environments that cause harm or discomfort to other living organisms or damage the environment, which can come in the form of chemical substances or energy, such as heat, light, or noise. Pollutants can be naturally occurring energies or substances but are considered contaminants when in excess of the natural levels. Santos divided environmental pollutants into biodegradable and nonbiodegradable ones. Biodegradable pollutants can be broken down and processed by living organisms, including organic waste products, phosphates, and inorganic salts. Nonbiodegradable pollutants cannot be decomposed by living organisms and therefore persist in the ecosphere for extremely long periods of time. They contain metals, plastics, glass, pesticides, and radioactive isotopes [1].

In recent years, people have been exposed to several types of substances with broad spectrum due to the rapidly evolving technology. Technology has brought us clear conveniences, and thousands of chemicals produced in different areas are up on the market every year. One of these chemical substance groups are pesticides [2,3].

#### **1.1. Pesticides**

Through the ages, it seems increasingly that people find a need to minimize the damage of pests with the use of pesticide chemicals and by other means [4]. Of the many examples of how pests have impacted human society, one of the most infamous is the Black Plague in Europe in the 14th century, when millions of people died from mysterious diseases. At that time, the diseases were believed to be because of God's punishment. A number of reports in the literature, art, and public statues certify the fear and destruction of those epidemics. Many years later, scientific data proved that a bacterial disease spread by rat fleas was the cause of the plague, which ruined almost the whole of Europe. Today, this disease, known as bubonic plagues, can be easily treated if it is properly diagnosed. Hence, controlling rodents including rats as well as fleas can reduce the relative frequency of the occurrence of diseases [5].

Ireland's potato crop destruction by a pest in the 19th century is another story. At that time, late blight, a plant disease, wasted potatoes in Ireland. Up to 1 million Europeans starved to death during the Great Irish Famine of 1845 to 1847. Late blight is still one of the major potato pathogens that chemists aim to synthesize new pesticides against [5].

Pesticides are chemical substances used on agricultural land but also in private gardens, along railways, and in other public areas [6]. The use of pesticides for crop protection is expected to increase based on a growing world population and the need for more food supplies. While pesticides increase agricultural production, bioaccumulation through the food chain can eventually become a risk to mammals because pesticides induce certain negative effects [7– 10]. Some parts of pesticides sprayed on crops will remain in farmland, but some of them will enter the surrounding soil, water, and air [11,12]. As artificial organic compounds, pesticides can remain in the environment for many years and may be transported over a long distance [13]. Pesticide residues in soil and water are significant environment threats and have been classified as carcinogen pollutants in many countries [14,15]. Hence, the excessive application of these compounds over the past half-century has posed serious risks to human health [16,17]. There have been numerous reports regarding pesticide residues detected in grains [8], milk [18], vegetables [19], and fish [20].

Although the benefits of pesticides have been immense, humans and other living organisms are often exposed to them in the environment [21]. Several epidemiological studies reported in the last two decades suggest harmful effects of pesticides on human health, including a possible relationship between pesticide use and cancers, such as non-Hodgkin's lymphoma, leukemia, and various types of solid tumor [22–24]. Public health concerns regarding the improper use of pesticides and poison have increased in recent years. To date, certain countries, regions, and international organizations have established maximum residue limits (MRLs) for foodstuffs. Additionally, national food monitoring programs for pesticides have been enacted worldwide [7–9] to ensure consumer health, improve the management of agricultural resour‐ ces, and prevent economic losses [10].

Despite the adoption of the International Code of Conduct on the Distribution and Use of Pesticides (Code of Conduct) [25], the strict control of banned/legacy pesticides has been proven difficult in many developing countries. This could be attributed to weak regulations on importation and use of dangerous substances and the activity or absence of control agencies at international borders [26]. This scenario has led to the proliferation of banned chemicals in local markets located in agricultural areas, making large quantities of pesticides available to rural farmers, which eventually could pose potential threats to the environment and the health of the people [27–29].

The existence of persistent chemical substances in the environment and their effects on the wildlife and mankind has raised a serious global concern. In this case, we need to mention the risks of pesticides.

Pesticides are poisons and can be hazardous. Fortunately, people are becoming more aware of their danger, and even producers are trying to produce safer chemicals and better applica‐ tion methods. Even the awareness is improving for risk-benefit ratio side; the job has not been completed yet. Misuses of pesticides still occur. On the contrary, even if they are used correctly, some pesticides can harm nontargeted living organisms and the environment. Just as the benefits of pesticides are real, so are the risks. The purpose of this publication is to explain the nature of pesticides and their history, classification, risks, and effect on health and the environment [4].
