European researchers have detectedvirus in about 40% of the more than 1,400 bathing water samples collected in coastal areasand indoorfrom nine countries, including Spain. Concentrations are low, but scientists recommend monitoring for these microorganisms in recreational waters, especially after heavy rains.
The European bathing water directive establishes limit values for bacteria, specificallyEscherichia coli and intestinal enterococci, which must not be exceeded to maintain water quality. Regarding viruses, however, the regulations only suggest conducting scientific studies that help determine reference parameters and reliable detection methods.
In this framework, 16 research groups of the Virobathe project -funded with EU funds- have analyzed the presence of adenovirus (virus with DNA) and norovirus (with RNA and causing gastroenteritis) in 1,410 samples of bath water, both fresh as navies, in nine European countries. In Spain, for example, scientists from the University of Barcelona (UB) examined the beaches of Gavà. The global results reveal that 553 samples contained viruses (39.2% of the total), especially adenovirus (in 36.4% of cases, compared to 9.4% with norovirus), and more in fresh water than salty water. . It was also found in a small selection of samples that a quarter of the microorganisms had the capacity to infect.
Theadenovirus is it sorelated to gastroenteritis in childrenyes, somerespiratory infections, otitis and conjunctivitis, although a large part of the population has already been in contact with them and is resistant to infection from most strains. The study, which has been published in the journalWater Research, points out that the presence of infectious adenovirus and norovirus in a water sample “may constitute a health riskAlthough adenoviruses do not necessarily pose a significant risk to the population in principle, if they are common strains that have already infected most people during childhood and remain in low concentrations, their populations may increase in bathing waters. after heavy rains to dangerous levels.
After heavy rains, virus levels take longer to return to acceptable levels than bacteria, used as standard indicators. In addition, many viral communities are more stable than bacterial communities in wastewater treatments, and are more resistant in seawater.
