Prohibited pesticides in Europe's rivers

Tests in ten countries do not find a single body of water without pesticide contamination

Taking a water sample in a canal. In their study, the researchers found no running water that was not contaminated with pesticides. © Jonathan Panduro Findalen / Greenpeace
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Contaminated Water: The water of European rivers and canals is contaminated with more than a hundred different pesticides - sometimes beyond the limits, as tests in ten countries now reveal. Among the chemicals are also 24 substances no longer authorized in the EU, as well as 21 veterinary medicines. Most pesticides were weed killers, but neonicotinoids were also present in increased doses, the researchers report.

Much of what people dump into the sewage or into the environment eventually ends up in the ground or in the waters. Researchers have repeatedly detected residues of pesticides, medicines and contrast agents in rivers and streams and even in drinking water. Even multi-resistant bacteria are no longer a rarity in German waters.

Researchers have again checked the extent of the water pollution in Europe with random tests. For their study, they took water samples in 29 rivers and canals in ten European countries, including Germany, France, Great Britain, Poland and Belgium. All water samples were tested for 245 different pesticides and 101 veterinary drugs.

Up to 70 pesticides at once

The result: no single waterbody was completely free of pesticides. "All European rivers and canals in this study were contaminated with mixtures of pesticides and, in most cases, with several veterinary medicines, " says Jorge Casado of the Greenpeacelabor at the University of Exeter. Overall, he and his team detected 103 different pesticides and 21 veterinary drugs in the water.

About half of the pesticides detected in the water were herbicides, the rest were insecticides or fungicides. Almost always, however, several of these active ingredients were present in one water sample one channel in Belgium contained even 70 pesticides at once. "We know that many of these pesticides are already individually questionable. But how these chemical blends affect wildlife and human health is poorly understood, "says Casado. display

24 no longer authorized pesticides

Another concern: in 13 of the 29 bodies of water, the concentration of at least one pesticide exceeded the EU's limit values. This was particularly the case for the neonicotinoids imidacloprid and clothianidin used against pest insects both of which are now banned for outdoor use in the EU. Also not permitted is the fungicide carbendazim. However, in 93 percent of their samples, the researchers detected this remedy in sometimes high concentrations.

Overall, Casado and his team found 24 pesticides in the rivers and canals that are not or no longer authorized in the EU. However, as they emphasize, this need not mean that farmers have used these funds illegally. Many of these backlogs could have come from the time before the ban or were released into the environment via approved operations. However, the concentration of some of these drugs is "notable, " according to Casado and his colleagues.

"Significant threat to the aquatic environment"

Residues of antibiotics in the water samples dominated the drug backlogs, the researchers report. In total, they detected 21 different drugs. An antibiotic from the group of beta-lactam antibiotics was particularly frequently represented: dicloxacillin was detected in two-thirds of the water samples, as Casado and his team report.

"Our studies of European waters have identified a significant threat to the aquatic environment at the time of sampling, " the researchers note. "We still do not know what it means to humans and animals if they are exposed to so complex and variable exposure to harmful chemicals - even if some of them are found in concentrations that individually are not questionable. "(Science of the Total Environment, 2019; doi: 10.1016 / j.scitotenv.2019.03.207)

Source: University of Exeter

- Nadja Podbregar