SCIENTISTS have discovered traces of almost 30 different drugs including antidepressants and antibiotics in York’s rivers.

Researchers from the University of York analysed water from the rivers Ouse and Foss at 11 sites in the city over a 12-month period.

They found 29 different drug compounds in the rivers, including some from drugs not usually available in the UK, thought to have been ingested by American and Chinese tourists.

The York University team stressed that although the levels were extremely low - drinking two litres of river water would give you about a millionth of a patient’s daily dose of one drug - there were concerns over the long-term implications.

They said that some drugs showed levels higher than previously observed across parts of Europe and Asia.

The research was overseen by Professor Alistair Boxall from the Environment Department who said that there was no evidence about the impact on human health, but the issue “deserves more investigation”.

He added: “It is a really complex issue to tackle and we don’t really have the methods to understand whether long-term exposure to low levels of pharmaceuticals matters or not.”

Professor Boxall said there were also questions over the impact of the drug traces on the ecosystem.

The research showed seasonal spikes, with higher levels of antihistamines in the summer and higher levels of drugs associated with cold and flu in the winter.