(CNN) Researchers in the UK have found traces of illicit drugs, pharmaceuticals and pesticides in samples of freshwater shrimp.

A study carried out by scientists from King's College London and the University of Suffolk tested the exposure of wildlife like freshwater shrimp to different micropollutants at 15 different sites in the county of Suffolk.

Scientists were surprised to find illicit drugs in samples in rural England, with cocaine found in all samples tested and ketamine also widespread.

"Such regular occurrence of illicit drugs in wildlife was surprising," Leon Barron from King's College London said in a press release.

"We might expect to see these in urban areas such as London, but not in smaller and more rural catchments."