Citizen science study finds high levels of E. coli in 1 in 3 watercourses

One in three watercourses in Flanders and part of Brussels contains too many harmful E. coli bacteria, according to research by the citizen collective Waterland reported by De Standaard on Friday. Waterland described the findings as “cause for concern”. 

Volunteers took samples at 401 sites in rivers, canals, streams and ponds over the past month. Of these samples, 385 tests yielded valid results. A third contained too much of the bacteria: more than 2,000 colonies per 100 millilitres. 

At 43 per cent of the measuring sites, the government’s standard for swimming water of less than 1,000 colonies was not met. At higher concentrations, children, the elderly and people with lower resistance are advised not to go into the water.

Bathing water quality

The bacteria come from three sources: animal manure, untreated household wastewater or via overflows that allow excess water from sewers to escape to a watercourse during heavy rain. More work is needed to define the source at each site, but overflow is likely to be the main cause at the worst points.

The Flemish Environment Agency says the bacterium is not the benchmark for assessing water quality ecologically but an indicator of bathing water quality.

Waterland chose to measure it as a parameter because the Flemish government does not systematically monitor it widely and it can be tested for quickly and easily. From May to September, Waterland monitors recreational ponds and waterways used for swimming.

E. coli can cause health problems such as abdominal pain, diarrhoea, vomiting or fever. High levels may be temporary, especially at overflows, as the bacteria only survive for a few days.


#FlandersNewsService | File image of a canal in Flemish Brabant © BELGIAN FREELANCE

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