Traces of cancer and psychiatric drugs were found in Britain’s tap water, according to a 100-page report commissioned by the Drinking Water Inspectorate (DWI).

Despite extensive purification treatments used by water companies, traces of bleomycin, a cancer chemotherapy drug, and diazepam, a sedative, have been found in the drinking water.

Though experts say the drug levels are too low to pose a direct health risk, concerns have been raised about exposing pregnant women to the drugs, which could harm an unborn child.

A separate study by the Centre for Ecology and Hydrology in Wallingford, Oxfordshire also revealed that chemotherapy drugs are being washed into Britain’s rivers. The report estimated that an adult who drinks more than three pints of water a day would receive doses of the drugs between 300 and 30,000 times lower than recommended safety levels each week.

Still, some experts are worried.

"There is not evidence to show that drinking water treatment removes all these drugs, so while we are not wanting to alarm people, it would be foolish to assume there is no risk,” said scientist Andrew Johnson, who led the Wallingford study.