Recent water tests have discovered that the River Cam has some of the highest concentrations of pharmaceuticals, pesticides, metals, and industrial chemical pollutants.

The testing was conducted by Watershed Investigations, the University of York and Surfers Against Sewage. The tests aimed to gather data on the level of pollutants found in the UK’s designated bathing water sites.

The investigation found that the three most common pollutants in the Cam were paracetamol, caffeine and chrysene. Chrysene is a hydrocarbon that originates from road runoff, combustion or as a component found in the banned preservative, creosote.

While the chemicals were not found at high enough concentrations to impact human health, the levels of chrysene are eight times the Dutch government’s limit.

Further to this data, LBC reported this month that phosphate levels in the Cam were 0.77 parts per million which is nearly three times more than the upper limit defined by the Water Framework Directive, and that E Coli levels were above what the Environment Agency considers to be “poor quality bathing water”.

LBC also reported that in reaction to these findings, Feargal Sharkey, an environmental campaigner, said: “If I lived in Cambridge, I would stay well away from swimming in the River Cam.”

Earlier this year, swimmers were advised against bathing in the river despite a 270m stretch at Sheep’s Green on Coe Fen being awarded bathing status designation in May. The spot has since consistently failed to meet the minimum standard of water quality.

The reports come at a time when Cambridge’s chalk streams – some of the rarest ecosystems in the world – are under significant strain. These streams are fed from underground water and rise through chalk bedrock to produce fresh and nutrient-rich water.

Tony Eva, a local environmental campaigner and producer of the documentary Pure Clean Water, has previously told Varsity that he believes the deterioration of the chalk streams is partly why the Cam’s water quality is lowering.

He said: “Because the chalk springs and streams don’t have the power that they used to, it means that the water coming out of sewage treatment plants which is of ‘acceptable’ quality should be diluted by lots of spring water. But when the springs and streams don’t have any power in them, it means that there’s very little of that that’s diluted, and so you have a much increased concentration of pollutants in the Cam.”

Another reason cited for the Cam’s reduced water quality is the rapid growth the city is experiencing. The construction of new data centres, labs and homes which has increased the demand for water abstraction, created industrial waste and put more pressure on water treatment facilities, all leading to worse water quality.

The environmental agency has previously raised concerns on the construction of 9,000 homes and 300,000 square feet of lab space in Cambridge due to the water stress it will bring. However, last April, Michael Gove, then Housing and Levelling Up Secretary, approved many Cambridge development schemes including Cambridge North and the Cancer Research Hospital despite the environmental concerns. It was determined that the benefits outweigh the risks for these developments and that new water strategies can be put in place to maintain water security.