Traces of cocaine and other illicit drugs have been found in freshwater shrimps in the UK, a study released on Thursday has revealed.
Scientists from King's College London and the University of Suffolk tested freshwater shrimps from 15 different sites across Suffolk, a largely rural area north-east of the UK capital.
Cocaine was found in all samples tested. Other illicit drugs such as ketamine, pesticides and pharmaceuticals were also widespread.
"Such regular occurrence of illicit drugs in wildlife was surprising. We might expect to see these in urban areas such as London, but not in smaller and more rural catchments," Leon Barron from King's College London, said.
Among the pesticides found was fenuron, which is banned in the UK.
"The presence of pesticides which have long been banned in the UK also poses a particular challenge as the sources of these remain unclear,” Barron added.
Thomas Miller, the lead author of the study — published in the Environment International journal — said, however, that "the potential for any effect is likely to be low".
Traces of cocaine and other drugs including amphetamine, methamphetamine and MDMA (ecstasy) were found in wastewater from approximately 46 million people across Europe earlier this year.
The European Monitoring Centre for Drugs and Drug Addiction tested wastewater from 73 cities across the continent and detected higher levels of four illicit drugs than in 2017.
Cocaine residues were highest in western and southern European cities, particularly in cities in Belgium, the Netherlands, Spain and the UK.