Why we need new parameters for river monitoring

For decades, the health of our rivers has been assessed using a set of well-established chemical parameters. But despite this long history of monitoring, the state of our waterways continues to decline. Clearly, something is missing.

John Attridge, Technical Director at Chelsea Technologies Group, believes the answer lies in a shift in focus—one that embraces new methods of analysis, particularly biological indicators.

"We've worked closely with the University of the West of England for nearly 15 years," Attridge explains. "Professor Darren Reynolds, who leads the group, has often pointed out that while we've been monitoring chemical standards for the past 40 or 50 years, our rivers are still in a dire state. That tells us we need a different way of thinking."

The Environment Act, designed to regulate sewage discharges and protect water quality, remains heavily reliant on a small number of prescribed parameters. But the real impact of pollution is biological, not just chemical.

Attridge and his team at Chelsea Technologies are advocating for the inclusion of fluorescence-based monitoring, which tracks biological responses in real time. "By measuring algae fluorescence, for example, we can gain a clearer picture of river health, beyond just chemical pollutants," he says. "We’re looking at how life in the water is actually responding to contamination."

To watch the full interview, click here.

Why we need to change the Environment Act (2021)

One of Attridge’s main concerns is that water companies will only monitor what they are explicitly required to by law. "The Act prescribes five key parameters, and then adds a vague line at the end that allows for 'anything else accepted by the Minister of State.' That’s not a strong enough mechanism to bring in new, more effective monitoring techniques."

Without a clear mandate, innovative biological sensors may struggle to gain traction. "The water companies will do what they’re told—but we need a way to integrate these newer parameters into routine monitoring, so they aren’t just an afterthought."

Chelsea Technologies is working to bridge that gap by developing plug-and-play sensor technology that can be integrated into existing infrastructure. "With the Environment Act requiring major investment in monitoring, we’re focusing on how our sensors can be easily bolted onto that new framework, adding crucial biological insights."

What is the future of river water monitoring?

Detecting algal blooms is already well established, but a greater challenge remains: distinguishing whether a bloom is toxic or not. "To do that, you need to get down to species-level identification or measure toxins directly," Attridge explains. "The concentrations involved are extremely low, yet still harmful at those levels. That’s a technological challenge we’re actively working on."

Chelsea Technologies, which originated as a spinout from Imperial College London, has spent 60 years developing advanced sensors across multiple fields, including environmental monitoring, ocean science, defense, and maritime applications.

"We have a strong scientific heritage, and our focus is on getting under the skin of the problem through precise measurement," Attridge says. "By bringing together expertise from different sectors, we can push water monitoring into a new era—one where we’re not just tracking chemicals, but truly understanding the biological health of our rivers."

As the UK grapples with worsening river pollution, the question remains: Will regulators and policymakers embrace these advanced monitoring tools? If not, we may continue measuring the problem without ever solving it.

To watch the full interview, click here.

By Jed Thomas

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