La pollution de l’eau par les micropolluants

Commissariat général au développement durableFeb 4, 2026

Les micropolluants viennent de la dégradation de substances plus grandes. Très petits et très mobiles, ils s’accumulent dans l’environnement, et tout particulièrement dans l’eau. Ils peuvent alors affecter les organismes vivants, dont nous faisons partie.

Micropollutants come from the degradation of larger substances. Very small and highly mobile, they accumulate in the environment, and especially in water. They can then affect living organisms, including ourselves.

3 chapters

Micropollutants: what are they?
Definition
• Micropollutants are small polluting substances found in water (and also in air and soil). Microplastics, for example, measure less than 5 millimetres and come from plastic degradation. • Even at very low doses, these substances can become toxic, especially when mixed together: this is called a cross-effect.
Human origin
Micropollutants come from human activities. More than 100,000 substances are used today in Europe, and new ones appear regularly.
Pollution sources
• heavy metals – from industry, transport, etc. • organic pollutants – chemicals, paints, plastics, cleaners, etc. • pesticides – from agriculture, fertilisers, household uses, etc. • hydrocarbons – used for energy, transport, industrial solvents, etc. • drug residues – from household, medical or veterinary use
What are the impacts?
Biodiversity impact
Micropollutants have a negative impact on biodiversity. Even in small quantities, they can be dangerous for aquatic plants and animals: increased mortality, mutations, deformities, sex change (in some fish species).
Health impact
• Our health is also affected. We can be exposed through food, drinking water or bathing water. • Some micropollutants are: • endocrine disruptors; • carcinogenic; • mutagenic (that is, capable of causing genetic mutations). • They can cause developmental, reproductive and behavioural disorders. The risks are still poorly understood.
Economic consequences
• There are also economic consequences: • treating micropollutants is costly for factories, drinking water and treatment plants, • some activities such as shellfish farming can be threatened. • Example: cadmium pollution nearly destroyed oyster farming at Marennes-Oléron (18,000 direct and indirect jobs affected).
Definition box
A micropollutant is an undesirable substance which, even at very low doses, has a negative effect on the environment and living organisms. Its presence is at least partly due to human activity (industrial processes, agricultural practices or everyday activities).
Widespread pollution
Concerning substances
Some micropollutants are particularly concerning:

Further reading

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