UK river monitoring has not been updated since the 1970s and provides only a snapshot of the state of water quality, making efforts to clean it up more difficult.
All four UK nations have similar methods when it comes to monitoring rivers. In England, for example, the Environment Agency (EA) collects water samples once a month to measure levels of pollutants such as phosphates and nitrates. These can lead to a reduction of oxygen in the water which suffocates aquatic animals and plants.
Of the nearly 1,500 rivers in the UK, samples are collected at more than 1,000 fixed sites, usually in the middle of the week between 9 a.m. and 4 p.m., says Pete Lloyd, a former EA official. This doesn’t give an accurate picture and may “only reflect the condition of the river for a few minutes,” he says.
Most pollutants enter rivers after it has rained, either by runoff from farmland or when raw sewage is diverted from sewers so it doesn’t overfill and return to homes. says Lloyd. With current sampling methods, which have been in place since the 1970s, it is coincidental if data collection occurs after it has rained.
“I understand why we were monitoring rivers this way 50 years ago: we didn’t know what was really causing river problems, so random sampling seems like a good idea,” he says. Lloyd. “But now that we know the problems, why don’t we be more specific with our monitoring? The system is decades out of date.”
According Penny Johns at the University of Bristol, UK, this inadequate sampling means that our knowledge of UK rivers has “absolutely colossal” uncertainties. In 2007, analyzed 39 years of daily data on total river phosphorus concentrationsdefined as a measure of the pollutant in all its forms. High total phosphorus can lead to algae bloomswhich can deplete the oxygen levels of the water, block sunlight and release harmful toxins.
To mimic EA sampling, Johnes analyzed data collected from different rivers on the same date each month, comparing it to the original data set. He found that just looking at water quality once a month misses important information about when phosphorus concentrations change. “The way we monitor rivers is highly variable across time and space,” says Johnes. “It’s not fit for purpose and hasn’t been for a long time.”
Although Johnes analyzed total phosphorus, UK regulators do not routinely monitor this content in rivers, despite the government’s desire to reduce their runoff from farms to water bodies by at least 40 percent by 2038. The EA, for example, only monitors rivers for reactive phosphorus, a soluble form that a spokesperson said is the type most easily absorbed by plants and algae. But Johnes says that undissolved phosphorus coming off farms makes up two-thirds of the pollutants in UK rivers.
Agencies also don’t regularly monitor rivers for some of the chemicals in consumer goods and pharmaceuticals, Johnes says. EA’s spokesman says he tests for more than 1,600 chemicals, but Johnes says thousands of newly synthesized chemicals could still be finding their way into rivers unmonitored.
Speaking on behalf of all UK regulatory bodies, the EA spokesperson says they are working with the pharmaceutical industry and research bodies to set up a task force to assess pharmaceuticals in wastewater discharge.
According to Johnes and Lloyd, the solution to the uncertainties of river monitoring is to introduce more intensive water quality controls and be more specific when collecting samples. “If you want to find out how agriculture is affecting a river, you need to collect samples after it rains,” says Lloyd. “If you want to find out how sewage affects a river, you should collect samples near a sewage overflow after it rains,” he says.
Much of this could be done through electronic sensors that fit into river banks and automatically record pollutant levels, Johnes says. Some of these are already in place, but more are needed, with more rigorous analysis of their data, he says.
The recent uproar over the dumping of sewage into UK rivers, a problem that has probably been around for years before becoming a popular issue, is a good example of how inadequate monitoring of water quality has let the public, says Lloyd.
This changed when Peter Hammond, a former mathematics teacher, filed a freedom of information request which found Raw sewage has been discharged 240 times into the River Windrush in England over the past three years.. He then sent dozens of similar requests to water companies across the country, revealing the scale of the problem. “Our monitoring system never caught it,” says Lloyd. “If it had, maybe we could have already done something about it.”
