top of page

Pesticides and Their Ripple Effect on Water


a tractor spraying chemicals on a field of crops


Image Source: aquaread.com


Pesticides are substances designed to deter, destroy, or mitigate pests. They come in various forms, from insecticides to herbicides and fungicides, each tailored to combat specific threats to crops. While their purpose is mainly to protect agricultural productivity, the extent of their reach often impacts beyond the intended target. In fact, other than residues in foPesticides are substances designed to deter, destroy, or mitigate pests. They come in various forms, from insecticides to herbicides and fungicides, each tailored to combat specific threats to crops. While their purpose is mainly to protect agricultural productivity, the extent of their reach often impacts beyond the intended target. In fact, other than residues in food, the most common way for the majority of people in the UK to be exposed to pesticides is, surprisingly, through spending time in urban, public areas.od, the most common way for the majority of people in the UK to be exposed to pesticides is, surprisingly, through spending time in urban, public areas.


Once applied, pesticides embark on a journey through various pathways, ultimately converging in our water bodies. Unfortunately, these days pesticides can be found in all bodies of water from rain and groundwater to streams, lakes, rivers and oceans. There are several ways in which they enter our waterways:


1. Surface Runoff:

Excessive pesticide application, especially during rainfall, can lead to runoff. This runoffcarries with it a cocktail of chemicals directly into nearby streams, rivers, and lakes.

2. Leaching:

Pesticides can infiltrate the soil, a process known as leaching. This allows them to seep downinto the groundwater, contaminating the water table.

3. Atmospheric Deposition:

Some pesticides have the ability to vaporise and become airborne. They can then bedeposited back to earth through rain or snow, contributing to the contamination of surfacewater.


Studies by the UK government show that in some samples of river water and groundwater, pesticide concentrations exceed those allowable for drinking water. These high levels of pesticides can be lethal to aquatic organisms. Even at low concentrations, they can disrupt thedelicate balance of aquatic ecosystems, affecting fish, insects, and other aquatic species. Certain pesticides will accumulate in the fatty tissues of organisms. This is called bioaccumulation and can result in the magnification of pesticide levels up the food chain. Pesticides can also lead to changes in the chemical composition of water bodies, affecting pHlevels and nutrient balances. This, in turn, can further disturb aquatic life.


Pesticides in water are not solely an ecological concern. They also pose a threat to human health. Pesticides can find their way into our tap water supply, potentially exposing humans to these chemicals through consumption. Farmers and agricultural workers are at the frontline ofpesticide use. Without proper protective measures, they may face direct exposure to these chemicals.



a diagram showing the impacts of pesticides



In an era where sustainable practices are paramount, it's crucial to reevaluate our approach to pesticide use in agriculture. By adopting eco-conscious strategies and implementing sustainable practices, we can strike a balance between pest management and environmental stewardship. Here are some practical steps to help you make more sustainable choices in pesticide use:


1. Embrace Integrated Pest Management (IPM)

Integrated Pest Management (IPM) is the cornerstone of sustainable pest control. It involves a multifaceted approach that combines biological, cultural, and mechanical controls, minimizing the reliance on chemical interventions. By utilising natural predators, crop rotation, and monitoring techniques, IPM reduces the need for excessive pesticide use, leading to a more balanced and resilient agricultural ecosystem.


2. Prioritise Organic and Biopesticides

Opt for organic-approved pesticides and biopesticides derived from natural sources. These alternatives offer effective pest control while minimising harm to beneficial organisms and reducing chemical residues in the environment. Organic and biopesticides are biodegradable and pose fewer risks to non-target species, making them a greener choice for pest management.


3. Conduct Thorough Risk Assessments

Before applying any pesticide, conduct a comprehensive risk assessment. Identify the target pests, their life cycles, and the potential impact on non-target organisms. Consider factors such as weather conditions, application methods, and dosage to ensure precise and efficient pesticide use. This thoughtful approach helps prevent over-application and minimises unintended harm to beneficial insects and wildlife.


4. Utilise Beneficial Insects and Natural Predators

Encourage natural predators like ladybugs, lacewings, and predatory mites that feed on common pests. Introducing or protecting these beneficial insects establishes a natural balance within the ecosystem, reducing the need for chemical intervention. By creating a hospitable environment, you can effectively manage pest populations while preserving biodiversity.


5. Monitor and Document Pest Populations

Regular monitoring of pest populations is essential for making informed decisions about pesticide use. Keep detailed records of pest activity, noting any fluctuations or trends. This data-driven approach enables you to apply pesticides only when necessary, preventing unnecessary treatments and safeguarding the environment.


For the gardener, PAN-UK have created a really handy printer-friendly document full of tips for a more organic approach to handling pests in the garden. You can download a copy HERE.


As stewards of the Earth, it is imperative that we acknowledge the intricate relationship between pesticides and water quality. Through sustainable agricultural practices and informed decision-making, we can strike a balance between safeguarding our crops and preserving our most vital resource - water.


Let us not forget that a thriving ecosystem and healthy agriculture are not mutually exclusive, but rather two sides of the same coin. It is time to sow the seeds of change for a greener, more sustainable future.


For more information and resources on pesticides and their impact on water, visit Pesticides Action Network UK.


a quote "never doubt that a small group of thoughtful citizens can change the world. Indeed, it is the only thing that ever has"


bottom of page