Rivers in England are contaminated with powerful insecticides, new testing has revealed, increasing concerns over the impact of the toxic chemicals on fish and birds. Neonicotinoids were banned from use on flowering crops in the European Union in 2013 due to the harm they cause to bees and other vital pollinators. Following even more evidence of harm, an EU vote to extend the ban to all outdoor uses is expected soon.

However, evidence is also growing that neonicotinoids – the world’s most widely used insecticide – harm other species, such as songbirds. Neonicotinoids have been in use since the early 1990s and now contaminate landscapes around the world. But very little monitoring of their concentration in soils or water is done, a failing recently condemned by a UK government chief scientific adviser.

The first systematic testing of neonicotinoids in rivers in Britain was mandated by EU water regulations and conducted in 2016. The results, obtained by the conservation charity Buglife, show that half of the 16 rivers tested in England had either chronic or acute levels of contamination. Of the 23 rivers tested across Britain, neonicotinoids were not detected in six.

No official limits exist in the EU for neonicotinoid pollution in freshwater. But a peer-reviewed scientific analysis published in 2015 recommended chronic and acute levels that should not be exceeded “to avoid lasting effects on aquatic invertebrate communities”, and these were used by Buglife to asses the new river data. Click here to read more