Shrimp with cocaine and ketamine in their systems have been fished up in Haverhill and across Suffolk.

Every shrimp caught in a study examining river pollution in the county had cocaine in its systems, new research by King's College London (KCL) has found.

Not only were the shrimp 'high on cocaine', but traces of ketamine, MDMA and a whole raft of recreational and prescription drugs were also found.

Animal species are commonly used to test levels of pollution, for example worms are often examined to determine if soil has lead in it. In this case researcher Thomas Miller tested freshwater shrimp to find out the level of contamination in five Suffolk rivers: the Waveney, Alde, Deben, Gripping and Stour.

Samples were taken from a number of sites along each river, including one on the Stour in the Haverhill area.

River Waveney, during the Suffolk Walking Festival

Shrimp feed by filtering nutrients from the water, which explains how they ingested the cocaine in the first place. It might also explain why Suffolk's potted shrimp is so popular.

It's not uncommon for trace amounts of drugs to be found in rivers. They tend to enter in waste water, so these shrimp are feeding on cocaine particles that have already been through people living in Suffolk. The fact that every single shrimp caught in the study had cocaine inside it suggests there is an awful lot going into the sewage system.

An underwater shrimp scene at the National Sea Life Centre in Birmingham

In his research paper explaining what he found, Dr Miller suggested that the drugs were only actually entering the rivers by mistake, and that most sewage plants would filter cocaine and other drugs out before pumping water into the rivers. Dr Miller suggests that it was sewage overflowing or leaking from pipes into the river which was to blame for the amount of cocaine found.

The levels found in the rivers won't affect human health, but does show how human pollution is affecting the environment in an all manner of ways. Dr Miller says in his paper's conclusion that further studies will be needed to discover exactly how these finding are actually affecting Britain's wildlife.