**Abstract**

Pesticide residues are the traces of pesticide compounds that remain on or in the crop, water, soil and air after the application. Pesticide residues get into the environment as a result of application or by accident and can be found in the air, water and soil. Pesticide residues, if present in air, soil and water can pose a serious threat to biological diversity and human health. After depositing in the environment, the pesticides start to break down and forms metabolites that are more or less toxic. Pesticide residues decline as the pesticide breaks down over time, therefore the levels of residues are highest immediately after the application and diminish as the crops continue to grow. When exposed to sunlight or microorganisms in the soil, most pesticides degrade easily however, the utmost number of pesticides after application scatter into non-target areas or leach into groundwater or move in surface runoff by misuse and misapplication while handling or spraying. The impact of widespread usage of chemical pesticides has made an uncountable number of effects on human health, environment and other life forms and has turned into a serious issue across the globe. The present study aims to present an introduction to the environmental pesticide residues and various aspects highlighting their impact on nature and biodiversity.

**Keywords:** Pesticide, Residues, Environment, Contamination, Human Health

#### **1. Introduction**

To ensure food safety around the world, it is important to build up all necessary measures to boost crop production. A crop loss due to pests is the biggest challenge our agriculture sector faces today. A decrease in crop yield from pest damage is one of the significant errands to guarantee crop productivity. Pesticides assume an imperative job in boosting rural profitability. The advantages of pesticides involve increased crop yield, expanded benefits for agriculturists and the counteractive action to crop diseases. Pesticides help farmers to overcome work costs by diminishing the measure of time required to control weeds and pests from fields. Pesticides are the chemical compounds that are used to control various pests and disease-spreading vectors like mosquitoes, ticks and household pests such as rats and cockroaches. The majority of the pesticides are used in agriculture to control various types of insect pests as well as non-insect pests like ticks and mites, weeds and fungal infestations and other crop diseases. Pesticides assume a comparative job in control the pests and enhance the crop from notorious pests thereby boosting the economy of a country. However, with the rise in global population, the crops are being cultivated on a large scale resulted in unrestricted utilization of pesticides. Pesticides have been linked to various environmental contaminations like soil, water and air [1]. In addition to control insect pests, weeds, vectors and other household pests, there has been a great impact of pesticide use on beneficial insects like pollinators, birds, fishes, non-target plants and on human health as well [2]. While utilizing the pesticides, the residues can remain in the environment for a long period and can be dispersed over a long distance. While spraying these chemical pesticides, a series of reactions can undergo; plants can take up pesticides through leaves and roots, the atmosphere can take up pesticides as vapors carried off as drift, pesticides can get ingested by insects, worms and microorganisms [3]. Soil is one of the final destinations of pesticides after application. Depending on the physical–chemical characteristics of the pesticide and soil, the pesticides may be sorbed the particles or be leached and/or carried on the surface by the rains reaching subterranean waters and rivers [4]. Pesticide residues in soil and water can pose a threat to biological diversity and human health. After getting deposited in the environment, the pesticides start to break down and forms metabolites that are more or less toxic [5]. Abiotic and biotic transformations play an important role in removing the pesticide residues from the environment. Environmental degradation of pesticides involves biotic transformation processes facilitated by microorganisms or plants and by abiotic processes such as chemical and photochemical reactions [6]. When a pesticide is applied on the crops the pesticide residues remain in the environment even when a farmer follows all label instructions. Pesticides can cause both acute and chronic effects on human health and the farmers are the most susceptible to intoxication. The pesticides especially the insecticides which are designed to control the insect pests have caused an unaccountable damage among the non-target insect pests which include insect pollinators such as honey bees, bumblebees, syrphid flies and insect predators which check the insect pest populations in an ecosystem, therefore breaching the protocols of insect food chains and food webs [7]. The avian fauna including some of the top predatory birds has also threatened by the large-scale utilization of chemical pesticides including the DDT, which is banned in more than 40 countries, however, very persistent and its residues are found to this day [8]. Fish diversity and other aquatic creatures both animals and plants are also affected by pesticides. The entry of pesticides into water bodies is because of man-made or by natural activities, therefore, can pose a serious threat to aquatic life. Agriculture is the main source of food across the planet and to ensure crop productivity, pesticides are indispensable, however, contamination of the environment raises concerns. The impact of chemical pesticides including health ailments among farmers and environmental contaminations has been reported from all parts of the world from both developed nations to developing nations [9].
