Micropollutants

Many substances are manufactured and used, and eventually find their way into the environment at very low concentrations, becoming organic micropollutants, of which there are now estimated to be 100,000, most of unknown toxicity for the environment. These include pesticides, medicines, cosmetics, flame retardants, perfumes, waterproofing and spot repelling treatments, plastifiers, insolating foams, etc. that do not degrade in the environment. A few persistent organic pollutants are now controlled or banned by international treaty, but most are still not regulated in any way. When we apply a sunscreen or take a medicine, we do not think about what happens to it afterwards. It is only recently that analytical techniques have been developed to detect and measure many micropollutants in the environment, and the results are a cause for concern.

While the concentrations of these micropollutants are so low that they are measured in nanograms per liter, they may still have significant effects. Some, for instance, are endocrine disrupters and effect the hormonal balance in humans and animals. Others may cause cancers or birth defects. The substances may also degrade, sometimes into even more toxic chemicals. Problem micropollutants include organic UV filters in sunscreens, polycyclic muscs used as perfumes in detergents (washing powders), phthalates used in plastics, and solvants. Medicines frequently found as micropollutants include analgesics, antiinflammatories, anaesthetics, antibiotics, betablockers, x-ray contrast products and antiepileptics. It is difficult and expensive to remove these micropollutants, so they can find their way into water supplies and food.

Given our lack of knowledge about what these micropollants are and what impact they may be having on human health and the environment, we should try to reduce all excessive or unnecessary use of the substances concerned. Choose sunscreens with mineral filters that reflect UV, rather than organic filters that absorb UV. Return unused medicines to the pharmacy; don't throw them in the toilet. Take paint, pesticides, solvents and toxic substances to a recycling centre. Use detergents and cosmetics with low environmental impact. Become a bio gardener without herbicides, insecticides or fungicides.

CIPEL (2009). Le point sur les micropolluants. La Lettre du Léman, Bulletin d'Information de la Commission Internationale pour la Protection des Eaux du Léman, No. 37, February 2009