Among the 151 detected chemical molecules, researchers have found pesticides, fungicides, common use biocides and sixty various compounds used in perfumes and cleaning products.
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Altitude lakes are not immune to pollution due to the activity of men. A study published in April in the scientific journal Science of the Total Environment reveals that 151 chemical molecules were detected in the waters of eight altitude lakes located in Ariège, in the Hautes-Pyrénées and Béarn. “A dozen of these molecules could not be characterized,” said Adeline Loyau, co-author of the study and specialist in wildlife diseases and mountain ecosystems at the Functional Ecology and Environment Laboratory located in Castanet-Tolosan , near Toulouse (Haute-Garonne).
To detect pollutant concentrations, the researchers plunged in summer and spring for silicone leaves in the lakes water. These leaves were then analyzed with a high resolution mass spectrometer by liquid and gas chromatography. “As we did not know what to expect, we sought 479 organic chemicals,” explains Dirk Schmeller, biologist of the populations, the other author of the study.
In the extracts collected, the researchers found pesticides, fungicides, common use biocides and sixty various compounds used in perfumes and cleaning products, probably transported by the atmosphere from the plains. “By adding the toxicities of all molecules, we arrive at chronic toxicity on the eight lakes. This can have effects on algae and crustaceans, which can destroy certain individuals and their ability to reproduce,” fears Mr. Schmeller.
Tourism and pastoralism
The authors of the study alert on the presence of two molecules “at a higher level of toxicity”: diazinon and permethrin. These insectors are applied to sheep, cattle and horses to rid them of sting insects. “We find permethrin in antiparasitic necklaces for dogs and in antimoustic sprays sprayed on shoes and clothes of hikers”, specifies Adeline Loyau, who suspects tourism and pastoralism to be sources of introduction of these molecules in high altitude.
The rate of the two chemical molecules -found in the Ayès pond in the Ariège Couserans, and Lake Acherito, near the village of Lescun (Pyrénées -Atlantiques) -, increases chronic toxicity to a higher level, and therefore risky. The team also notes that the greater the presence of the two toxic compounds, the more that of microscopic crustaceans decreases. However, “microcrustaceans are very important elements of the plankton. They filter the particles and have a water cleaning function. But their disappearance changes the ecosystem of these lakes, in addition to the effects of global warming, and can Impact the quality of the water that may no longer be drinkable, “says Dirk Schmeller.
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