Serious concerns as high levels of pharmaceuticals discovered in Humber estuary

Scientists from the University of Leeds, University of Hull and Catalan Institute for Water Research in Spain have analysed water samples from the Humber estuary taken over 12 months to determine the concentration levels and any trends during the year.

Five target drugs were measured for the study based on their prevalent usage – ibuprofen, paracetamol, diclofenac, trimethoprim and citalopram.

High rates of all the targeted pharmaceuticals were found in the Humber estuary with 66 per cent of the samples detecting diclofenac - a drug highlighted for potential environment concern as its veterinary use on cattle in India has driven a sub-species of vultures to the brink of extinction. The drug was recently recalled as an over the counter drug and is now only available on prescription.

Up to 97 per cent of the samples also showed ibuprofen with levels that could be toxic to organisms living in rivers and estuaries.

Dr Paul Kay, from the University’s research centre water at Leeds said: “The Humber estuary receives the sewage effluent for approximately 25 per cent of the population of England, so it might be unsurprising that all five target pharmaceuticals were detected at relatively high levels. What’s particularly worrying is this indicates that they are not breaking down or being diluted in the way we would expect in such a big body of water. It could be case that the chemicals are so prevalent that dilution is not possible.

“Pharmaceuticals are designed to be biologically active, even at low levels. The ubiquitous use of pharmaceuticals and their presence in household wastewater means there is a continuous low level input of these chemical compounds into the aquatic environment, which builds up to a huge amount over time.”

Samples were taken from eleven additional estuaries around the UK for comparison.

The occurrence of the targeted drugs varied, but ibuprofen and paracetamol had the highest concentrations.

The Humber, which has a large catchment area and is heavily urbanised, had the overall highest concentration of pharmaceuticals compared to the other estuaries and therefore represents a worst case for pharmaceutical pollution at the sampling sites.

Scientists carrying out the research described the findings as a “serious concern” but said more research needs to be done to “effectively shape and inform regulations and policies” to protect the freshwater environment.