In agriculture and for many gardeners, pesticides are an important part of what they do. But their use has a profound impact on our environment in several ways.
Pesticides are a group of products that are used to kill a variety of unwanted plants and insects seen as pests. They include insecticides, herbicides, fungicides and others, targeting a wide range of organisms that are seen to interfere with what we want to grow.
While the use of pesticides happens on a large scale in agriculture, the impact their use in domestic gardens has shouldn’t be underestimated. Because although the negative impact on our environment is smaller, it’s still there.
So how are pesticides bad for the environment? Let’s find out…
1. Soil Pollution
Pesticides are used in various ways, depending on what pest or weed they aim to eradicate. However, many of the chemicals will end up in the soil. We know that because researchers have tested soils to check for commonly used pesticide chemicals.
One study found pesticide residues in the topsoil of countries across Europe. In 83% of soils they found one or more residues and in 58% two or more. (Ahmad et al., 2024) The issue is that many of the commonly used pesticides, for agricultural or domestic use, will persist in the soil.
There they accumulate and increase over time. Another issue is bioaccumulation or biomagnification. That’s when the chemicals enter an organism, which is then eaten by another organism and so on. The concentration of the chemicals increases every time a contaminated creature is eaten. (Arias-Estévez et al., 2007)
Studies have shown that these chemicals lead to a degradation of the soil, due to harming the microorganisms that live in it. They also disturb the ecosystem, making the soil less healthy.
Pesticides in the soil can lead to reduced soil fertility, as the nutrients that are present aren’t transformed into a form that plants can access them. (Hussain et al., 2009)
And it’s not just the microorganisms that are impacted. Studies have shown that earthworms that live in the soil also suffer when pesticides are present in their environment. A study has shown that the number of diversity of earthworms in contaminated soil is much lower.
The researchers also tested the toxicity of the pesticides by exposing earthworms to the chemicals. Even at low concentrations, the invertebrates died within 24 or 48 hours. And any worms that survived showed signs of harm, such as reduced weight. (Jeyaprakasam et al., 2020)
Not only are earthworms incredibly important for the soil ecosystem, they are also a source of food for many other animals, such as birds and mammals.
But why is soil pollution a problem? Because you need healthy, functional soil to grow healthy plants. Plants are an important part of our fight to beat climate change. They capture and store carbon, which keeps it from contributing to global warming.
If soils degrade, some plants might not be able to grow any more because of changed conditions and a lack of the right microorganisms. This will lead to a biodiversity loss, which we know is a bad thing for our environment.
There’re ways to ensure your soil’s microbiome is healthy, such as not using pesticides and adding garden probiotics to your soil.
2. Air Pollution
There are different ways pesticide particles can end up in our atmosphere. Most pesticides are sprayed on plants or soil, but not all particles will hit their target, as droplets can be blown away by wind.
After the pesticides have been applied, the pesticide will evaporate, taking some of the chemicals into the atmosphere through the vapour. Finally, the wind can also blow contaminated soil particles into the air. (Mueller et al., 2015)
A study from Austria has found various pesticide particles in the air and not just around farmland, but also in National Parks and city centres. Some of the chemicals found weren’t even legal in Austria, which begs the question if they have blown over from a different country. (Zaller et al., 2022)
These airborne pesticide particles will harm a wide range of fauna, including bees, birds, mammals and insects. (DiBartolomeis et al., 2019; Schulz et al., 2021; Tassin de Montaigu et Goulson, 2020) But it’s not just animals, as plants are also affected. (Schmitz et al., 2013)
A reduction in wild plants means less food for a wide range of insects, which are at the bottom of the food chain, and animals that feed on them.
The particles can also land on soil, where they can impact on the soil ecosystem, as we have seen earlier. Air pollution is a huge problem, because it means that the pesticides can reach pretty much every part of the environment where they weren’t meant to go.
But how else are pesticides bad for the environment? Let’s find out.
3. Water Pollution
One area these airborne pesticide particles can pollute is our waterways, leading to water pollution. Although this isn’t the only or main way pesticides make their way into our lakes, rivers and oceans.
Pesticides can also enter our waterways through the soil, from where they can enter groundwater and surface water. (Arias-Estévez et al., 2007) But pesticide runoff on agricultural land also transports pesticides into our waterways. (Hüesker et Lepenies, 2021)
And once in our waterways, the chemicals are harmful and often toxic to aquatic life. To confirm this, all you have to do is to look at the label of a pesticide, like an insecticide. The vast majority state that they are toxic to aquatic life.
There are plenty of studies that have shown that pesticides can harm marine ecosystems and are harmful to marine life. Researchers have shown that pesticides are toxic to riverine invertebrates (Poyntz-Wrights et al., 2023), fish (Saha et Dutta, 2024) and water insects (Cochard et al., 2013).
One study also showed that exposure of pesticides in the water also altered the behaviour of zebrafish, an indicator species that is often studied. (Morrison et al., 2024)
4. Loss Of Biodiversity
It might not come as a surprise that the use of pesticides contributes to the loss of biodiversity. We have seen that these harmful chemicals don’t just affect the species they are meant to control, but also a wide variety of non-target species.
Because the pesticides manage to reach so many different areas, their impact is huge. We know that many insecticides used to control pests also negatively affect bees (Schwarz et al., 2023), which are important pollinators.
Without them, many plants wouldn’t be able to produce seeds and spread. The vast majority of food we grow needs pollinators to produce fruit. So the impact of biodiversity loss is much more wide-ranging.
It’s estimated that around 1 million species are at risk of extinction. (Pfenning-Butterworth et al., 2024) While this isn’t due to pesticides alone, as many other factors also play a role, it’s a main one that needs to be addressed.
While extinctions are part of nature’s way to keep the balance, the mass extinction that the world faces today risks tipping this balance. And we don’t know what will happen if the balance is out of kilter, but it won’t be a good thing.
We know that biodiversity loss drives climate change, which further disturbs the balance. Extreme weather events have become more frequent and stronger, which will just get worse if we can’t stop it.
In view of this, we need to find other solutions than using chemical pesticides that harm our environment and fuel climate change.
Conclusion – How Are Pesticides Bad For The Environment
As we have seen, the main issue with pesticides is that they don’t just affect the target species, but also a whole host of non-target ones. To make things worse, the harmful chemicals manage to get into different areas of the environment, causing soil pollution, air pollution and water pollution.
Many of the pesticides used take a long time to degrade, which means they persist in the environment for a long time. Chemicals that have been banned decades ago are still detected in the environment today.
The consequence of all that is biodiversity loss, which is one driver of climate change.
While most of the above-mentioned studies looked at agriculture, the use of pesticides in our gardens has the same impact, but on a much smaller scale. However, it’s an area that we can easily influence, unlike farming practices.
And there are studies that showed that the use of pesticides in gardens has a negative impact on the environment. A study has shown that gardens, where pesticides were used, saw a 7% reduction in butterfly richness. (Tassin de Montaigu et Goulson, 2023)
The same researchers also looked at the impact of birds when pesticides were used in gardens.
The number of birds visiting a garden in which pesticides are used is lower than if they weren’t used. House sparrows, great tits, robins, blackbirds and many other species that we are used to seeing in our gardens won’t visit as much if you use pesticides. (Tassin de Montaigu et Goulson, 2023)
These and similar studies tell us that we can make a difference. By creating eco-friendly gardens, we can give wildlife a place to thrive. And you don’t need to use chemicals to keep your plants safe from pests. There are many ways to control pests in an eco-friendly way:
- Encourage predatory insects
- Companion planting
- Physical barriers
- Crop rotation
- Use probiotics for the garden
We can all make a difference for nature, and our gardens can become safe havens for us and wildlife. Make the change: stop using pesticides and create a sustainable garden.
