Pesticides are made of hazardous chemicals and are sprayed on crops on purpose to keep out undesirable pests, including weeds, fungi, insects, and rodents. They include an extensive range of chemical products, including fungicides, insecticides, and herbicides.
Although pesticides have been crucial in generating enough food to feed the world’s population because of their ability to increase crop yields, a startling 98% of insecticides and 95% of herbicides fail to reach their intended target.
Rather, they become a part of the larger environment, one of the several sources and varieties of agricultural pollution that can have catastrophic effects on the planet.
When pesticides leak from storage tanks, runoff from fields, and are improperly disposed of, especially when sprayed from above, they can quickly pollute the air, ground, and water.
Table of Contents
Environmental Impacts of Pesticides
- Aquatic Life
- Pesticide Resistance
- Pest Resurgence
Pesticides can find their way into streams, rivers, lakes, reservoirs, coastal waters, and subterranean supplies through a variety of channels: they can seep through the ground, enter waterways through agricultural runoff following heavy rains, drift beyond the area where they were sprayed, or spill during application, storage, and transportation.
Not only may it damage aquatic life, but it can also taint human drinking water.
For a long time, it was thought that the natural filtering that occurs as water slowly moves over rock formations, sand, gravel, and soil would be sufficient to remove impurities before they reach groundwater.
Many pollutants, including certain pesticides, have been found in groundwater these days. Recharge can transport contaminants into aquifers, according to studies. Moreover, it becomes obvious that pollution of the recharge water may result from human activity.
Not all groundwater is at the same risk of pesticide pollution. It is less probable that pollutants will reach groundwater the lower the water table is below the surface of the land.
In comparison to a shallow aquifer, a deep aquifer offers more time and chances for pesticide adsorption, degradation, and other processes.
Another crucial factor is the geologic layers’ permeability between the groundwater and the soil’s surface. Water can migrate to groundwater more easily in cases where the materials above the water table are relatively coarse, like sand, gravel, or highly fractured rocks than in cases where the layers are less permeable, like clay or solid rock.
Because bedrock, such as limestone, dissolves readily and forms channels and depressions in the land surface, it can make groundwater especially vulnerable to contamination. The so-called sinkholes can serve as a direct conduit for groundwater to reach the soil’s surface.
Because the soil lining the bottom of a sinkhole is frequently thin and offers minimal screening of contaminants that enter, contaminated water that drains into a sinkhole can easily enter groundwater.
Pesticides are intended to promote plant growth, but over time, they may hinder it. This is because the chemicals in them have the potential to lower the amount of organic matter in the soil, which would impair the soil’s capacity to hold moisture and lower its general quality.
Pesticide usage reduces the soil’s overall biodiversity. This not only immediately harms biodiversity, but it can linger in the ecosystem for a long time and eventually build up to dangerous levels, which results in decreased crop yields in the future.
The soil becomes home to a significant portion of the pesticides used in agriculture and other uses. Using pesticides repeatedly and indiscriminately makes the problem of soil accumulation worse.
Some factors, such as the properties and microflora of the soil, influence how pesticides are applied. As a result, the pesticides experience a range of transit, adsorption/desorption, and degradation processes.
Pesticide degradation affects the microbial diversity, metabolic processes, and enzymatic activity of the soil via interacting with native microorganisms and the soil itself.
Pesticides present in soil interfere with plants’ ability to fix nitrogen, which is essential for the growth of many large plants. Crop yields may significantly fall as a result of this. When poisons are sprayed on blooming crops, honeybees—which are important pollinators—die. Moreover, this reduces crop reproduction and pollination.
A certain amount of pesticides are blown away by the wind before they can reach the intended crop. Additionally, they might vanish at a later moment or time.
Conditions like temperature, humidity, and wind direction can cause different compounds to behave differently and even carry them hundreds of miles away. While some of these compounds are pollutants in and of themselves, others can react with airborne particles to produce other pollutants, like ground-level ozone.
Even though the purpose of pesticides is to precisely target pest plants, animals, and fungi, other species frequently end themselves in the crossfire.
The bee population is one well-known example of this, as it is now known that some of the most commonly used insecticides (like neonicotinoids) permanently harm bee populations. Since bees are essential pollinators, news of their global population fall is extremely alarming for biodiversity worldwide.
Pesticide residues that cling to food after spraying can poison animals. When pesticides are used in a given area, they might destroy the food sources that some animals depend on, forcing the animals to move, alter their diet, or go hungry.
Additionally, pesticides may bioaccumulate in the bodies of animals that eat plants or insects treated with them, infecting every food chain in the process. For instance, pesticide-contaminated insects and worms can affect birds.
Amphibians are tetrapod, ectothermic animals belonging to the class Amphibia. They live in many different types of habitats; the majority of species are found in terrestrial, freshwater, aquatic, fossorial, and arboreal environments.
The worldwide decrease in the amphibian population has raised concerns about the environment. With 7.4% of amphibian species classified as highly endangered and at least 43.2% of them experiencing population declines, many of these species are in danger of going extinct.
The diversity of amphibian species is declining for a variety of reasons, but pesticides seem to be a major one. The impact of pesticides on amphibian populations may have grown due to the more varied and warmer temperatures brought about by climate change and global warming.
Numerous studies have revealed that frogs’ dual aquatic-terrestrial cycle, permeable skin, and comparatively weak immune systems make them vulnerable to environmental pollutants.
There is proof that the usage of pesticides is harming birds. In her book Silent Spring, Rachel Carson describes how the buildup of pesticides in the tissues of several bird species has resulted in their extinction.
Certain fungicides used in farming may kill earthworms, which can lower the number of birds and mammals that eat the worms, but they are only mildly hazardous to birds and mammals. Furthermore, because certain pesticides are granular, birds and other wildlife may ingest the granules, believing them to be food grains.
A little bird only needs a few pesticide granules to be killed. By destroying their habitat, herbicides may potentially put bird populations in jeopardy.
10. Aquatic Life
Water tainted with pesticides may be harmful to fish and other aquatic biota. Herbicide application to bodies of water can result in plant death, lowering the oxygen content of the water and smothering fish.
Certain pesticides can alter fish’s physiology and behavior over time, leading to lowered immunity to disease, increased inability to elude predators, and nest abandonment, among other behavioral changes that lower population sizes.
11. Pesticide Resistance
When a product consistently fails to provide the desired level of control when used according to the label indication for that pest species, it can be interpreted as a heritable shift in the sensitivity of the insect population.
In a typical community, resistant individuals are often uncommon, but the careless use of chemicals can wipe out normal susceptible populations, giving resistant individuals a selective advantage when pesticides are present.
In the absence of competition, resistant individuals keep proliferating and eventually over time take over as the majority of the population. When the majority of a population develops resistance, the insecticide loses its effectiveness and insecticide resistance begins to manifest.
The biggest obstacle to the effective use of pesticides in modern times is resistance. Many targeted pest species worldwide have developed resistance as a result of the extensive use of insecticides.
12. Pest Resurgence
Pest resurgence is defined as the rapid reappearance of a pest population in injurious numbers following pesticide application. The use of persistent and broad-spectrum pesticides that kill beneficial natural enemies is thought to be the leading cause of pest resurgence.
However, some factors have been linked to the resurgence, including an increase in insect pests’ feeding and reproductive rates brought on by the application of sub-lethal pesticide doses and the occasional creation of favorable conditions by the removal of a primary pest that allows secondary pests to develop into primary or key pests.
Effects of pesticides on non-target organisms
The effect of pesticides on non-target organisms has been a source of worldwide attention and concern for decades. Adverse effects of applied pesticides on non-target arthropods have been widely reported. As a result, natural insect adversaries like parasitoids and predators suffer greatly from insecticides.
Since natural enemies are crucial in controlling pest populations, their extinction might make pest issues worse. In most cases, extra insecticide sprays are needed to manage the target pest in the absence of natural adversaries.
Secondary pest outbreaks may arise when natural enemies that typically control small pests are also impacted in certain situations. In addition to their natural enemies, soil arthropod populations are severely disrupted by the uncontrolled use of pesticides in agricultural systems.
The soil food web is made up of soil invertebrates, which include nematodes, springtails, mites, micro-arthropods, earthworms, spiders, insects, and other microscopic animals that facilitate the breakdown of organic compounds such as leaves, manure, plant residues, etc.
They are necessary for the organic matter’s transformation, mineralization, and preservation of the soil’s structure. Therefore, pesticide effects on the aforementioned soil arthropods have a deleterious influence on multiple food web linkages.
Although the original uses of pesticides were to boost agricultural output and prevent infectious diseases, these benefits have been outweighed by the negative impacts of pesticide use.
Because pesticides are persistent, they have had such an impact on our ecosystem that they have made their way up the food chain and into higher trophic levels, including the diets of humans and other large mammals. Ingestion of contaminated food, water, or air has now been linked to the emergence of several acute and chronic disorders in humans.
This is the moment when using pesticides correctly is essential to safeguarding our environment and any potential health risks.
The amount and frequency of pesticide treatments used could be decreased by utilizing alternative pest control strategies like integrated pest management (IPM), which integrates several control techniques like cultural control, the use of resistant genotypes, physical and mechanical control, and cautious chemical use.
Furthermore, cutting-edge techniques like biotechnology and nanotechnology may make it easier to create herbicides with fewer side effects or resistant genotypes.
The answer to lessening the harmful effects of pesticides on our environment lies in community development and numerous extension programs that might inform and encourage farmers to use cutting-edge IPM tactics.
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A passion-driven environmentalist by heart. Lead content writer at EnvironmentGo.
I strive to educate the public about the environment and its problems.
It has always been about nature, we ought to protect not destroy.