Combating diffuse pollution to preserve biodiversity

Unlike point source pollution, non-point source pollution is insidious and stems from a multitude of dispersed sources: transportation, industrial activity, agriculture, and household use. These contaminants (pesticides, drug residues, microplastics, etc.) accumulate silently and create a toxic “cocktail” effect that now exceeds the self-purification capacities of ecosystems. More than mere degradation, this pollution disrupts the very mechanics of life. Chemical contamination disrupts fundamental balances: “dead soils” lose their filtering power, insecticides disorient pollinators—the guardians of our food security - and endocrine disruptors block fish reproduction. It is not only human health that is threatened, but nature’s ability to regenerate.
This widespread contamination knows no borders. The traditional “silo” approach—treating air, water, and soil separately—has become obsolete in the face of the reality of cross-media transfer: today, there are 140 tons of pesticides in the clouds (study by Clermont Auvergne University/CNRS/Météo-France, 2025), which then fall into rivers, themselves contaminated by pharmaceutical residues or heavy metals, for example. Faced with this pervasive pollution, remedial solutions (decontamination) are often impractical and very costly. The most effective solutions involve prevention and reduction at the source. In this regard, investment is too low: society spends €46 billion annually to combat pollution, while indirect costs (health, biodiversity) exceed €200 billion (Ministry of Ecological Transition, 2021). In other words, the costs incurred far exceed the investment made.
Yet, when proactive, public action proves its effectiveness. The improvement in air quality in the Île-de-France region over the past twenty years is a striking example: standards and investments have reduced the number of deaths linked to fine particulate matter from 10,350 to 6,220 per year between 2010 and 2019 (Airparif/ORS). This type of success can serve as a real guide for preserving and promoting the widespread presence of biodiversity.
So how can we combat diffuse pollution?