What are pesticides?  The term "pesticide" is a composite term that includes all chemicals that are used to kill or control pests. The term ?pesticide? can applied to any chemical that is used to eliminate, reduce or control pests during agriculture which includes herbicides against weeds, insecticides against insects, fungicides against fungi, nematocides against nematodes, and rodenticides against small vertebrates . Pesticide pollution is the hardest and most undesirable impact of biocides intentionally released in the environment as an agricultural resource on human and plant health.

Farmers are heavily reliant on these agrochemical inputs as they are cheap, effective and readily available. They help agriculturists, operating on both big and small scales, to defend their harvest against pests, and maximise their profits. With advancements in farming technology and the rapid increase in intensive agricultural practices, the use of pesticides has skyrocketed. The flipside, however is, that these are ultimately harsh, sometimes unresearched chemicals, released into the environment with an intention to destroy specific organisms.

What are some effects of pesticide pollution?

Firstly, soil is contaminated by pesticides. This can occur through one of many ways, such as spray drift during treatment of plants and wash-off from the treated foliage. It may be released from granulates or from treated seeds in the soil. Some soil fumigants and nematicides are added directly to the soil. The spread, persistence and presence of these pesticides in the soil depend on the properties of the soil as well as the product. The addition of pesticides to the soil affects water absorption, degradation and the uptake of organic matter and other such soil processes.

Water is also polluted by pesticides. Pesticides may enter the water by drift while spraying the plants with pesticides, by runoff from a treated area or direct application to control pests that breed and arise in stagnant water. The degree of contamination is dependent not only on the hydrophobicity and solubility of the pesticide, but also on the distance of the source of application to the water source.

Pesticides impact and disrupt the working of the terrestrial ecosystem. In microorganisms, pesticides can alter the soil processes carried out by the soil microbes. These include nitrification, decomposition of organic matter, and the overall maintenance of soil structure. The pesticides can inhibit the population growth of these organisms and suppress important biological processes critical for their survival. They also attack soil Invertebrates like nematodes and microarthropods, which are an essential part of the soil food web, comprising one or more trophic levels. They may facilitate processes such as the turning of soil (reducing runoff and increasing porosity), and mineralization of dead and decaying organic matter for uptake by the plants. Pesticides stunt their growth and reproduction processes, and have intense adverse effects on their population. They may also restrict their feeding activity and cause behavioral changes in these organisms.

Organisms such as bees and butterflies also face decline following an intensification of farming activity and an increased use of pesticides. Unconsidered agricultural practices often cause weight reductions, population decline and produce altered and irrational behavior in bee and butterfly populations. 

Birds are primarily affected by the reduction or contamination of food supply, specifically intensive farming practices entailing the use of pesticides during the breeding season. The resulting reduction in chick mortality has caused a significant drop in bird populations in areas of farming with multiple agrochemical inputs. Pesticides also cause a loss of biodiversity.  Intensive usage of pesticides has severely affected habitat heterogeneity over the past few decades. A loss of biodiversity directly corresponds to disastrous consequences for the consummate food web and agricultural practices in the future.

Mixtures of pesticides are commonly detected in the environment and exposition to organisms can be more dangerous than individual effect. 

Pesticides have profound adverse effects on human and environmental health. A multitude of different solutions have been proposed in the past to mitigate pesticide pollution, including but not restricted to bans and taxes on certain chemicals, pesticide registration and so on. In the future, proposed solutions to combat pesticide pollution can range from biopesticide research, farmer education, and new legislature.