UK river pollution monitoring is 50 years out of date, researchers say

Scum floating on the River Ribble near Clitheroe in Lancashire, UK

Scum floating on the Ribble River near Clitheroe in Lancashire, UK

Ashley Cooper/Alamy

Monitoring of rivers in the UK has not been updated since the 1970s and only provides a snapshot of the state of water quality, making restoration efforts difficult.

The four British nations have similar methods when it comes to policing rivers. In England, for example, the Environment Agency (EA) takes water samples once a month to measure levels of pollutants such as phosphates and nitrates. These can lead to a lack of oxygen in the water, leading to suffocation of aquatic animals and plants.

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Of the UK’s nearly 1,500 rivers, samples are collected from more than 1,000 fixed locations, usually in the middle of the week between 9am and 4pm, says Pete Lloyd, a former EA official. This does not give an accurate picture and may “reflect the state of the river for just a few minutes,” he says.

Most pollutants enter rivers after rainfall, either by runoff from farmland or when raw sewage is diverted from sewers so it doesn’t overfill and flow back into homes, Lloyd says. With current sampling methods, in use since the 1970s, when data collection occurs after a rainfall, it is a coincidence.

“I understand why we monitored rivers this way 50 years ago – we didn’t know what was actually causing problems for rivers, so sampling sounds like a good idea,” he says lloyd “But now that we know the issues, why not be more selective in our surveillance? The system has been outdated for decades.”

According to Penny Johnes of the University of Bristol, UK, this under-sampling means there are “absolutely colossal” uncertainties in our knowledge of UK rivers. In 2007, she examined 39 years of daily data on total river phosphorus concentrations, defined as a measure of the pollutant in all forms. High levels of total phosphorus can lead to algal blooms, which can reduce oxygen levels in the water, block sunlight and release harmful toxins.

To mimic the EA’s sampling, Johnes analyzed data collected from different rivers on the same day each month and compared it to the original data set. She found that looking at water quality just once a month is missing important information about when phosphorus levels are changing. “The way we monitor rivers varies greatly in time and space,” says Johnes. “It’s not useful and hasn’t been for a long time.”

While Johnes examined total phosphorus levels, UK regulators do not routinely monitor it in rivers, although the government aims to reduce runoff from farms into water bodies by at least 40 per cent by 2038. Only the EA monitors rivers for reactive phosphorus, a soluble form that a spokesman says is the type most easily taken up by plants and algae. But Johnes says undissolved phosphorus runoff from farms accounts for two-thirds of the pollutant in UK rivers.

Authorities also don’t regularly monitor the rivers for chemicals in consumer goods and pharmaceuticals, Johnes says. The EA spokesman says more than 1,600 chemicals are being searched for, but Johnes says thousands of newly synthesized chemicals could still be entering rivers unchecked.

Speaking on behalf of all UK regulators, the EA spokesman said they are working with the pharmaceutical industry and research bodies to set up a working group to look for medicines in sewage discharges.

According to Johnes and Lloyd, the solution to the uncertainties in river monitoring is to introduce tighter controls on water quality and be more selective in sampling. “If you want to find out how farming affects a river, you need to collect samples after it rains,” says Lloyd. “If you want to find out how wastewater affects a river, you need to collect samples near a wastewater overflow after it has rained,” he says.

Much of this could be done via electronic sensors that fit into riverbanks and automatically record pollutant levels, Johnes says. Some of these already exist, but more is needed with a more thorough analysis of their data, she says.

The recent uproar over UK river sanitation, a problem that probably existed for years before becoming a popular issue, is a good example of how poor water quality monitoring has disappointed the public, says Lloyd.

That changed when Peter Hammond, a former mathematics professor, submitted a request for information, which found that untreated sewage had been dumped into England’s Windrush River 240 times in the past three years. He then sent dozens of similar requests to water companies across the country, revealing the scale of the problem. “Our surveillance system never detected it,” says Lloyd. “If so, maybe we could have done something about it by now.”


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