Swimming in rivers and lakes more than doubles the risk of developing skin problems even when the water meets safety standards, according to a Hungarian study.
Researchers analyzing data from 2,368 volunteers across four freshwater beaches in Hungary found that bathers faced significantly higher rates of rash, itching, and sores compared to people who stayed on dry land. The findings were published in the International Journal of Hygiene and Environmental Health.
During the randomized controlled trial, investigators instructed one group of participants to spend ten minutes in the water and submerge their heads completely at least three times. A control group remained on the shore. All four freshwater bodies tested during the study complied with current European Union water quality regulations.
Bacterial Risks and Skin Reaction Causes
Water pollution involving Escherichia coli bacteria showed a direct link to gastrointestinal illness among swimmers. For every tenfold increase in E. coli concentration, the risk of stomach disorders rose by approximately 73 percent. Elevated levels of certain bacteriophages, which are viruses that indicate fecal contamination, raised gastrointestinal illness risks by 45 percent.
Skin issues emerged regardless of the level of fecal contamination present in the water. Scientists attributed part of the skin irritation to swimmer's itch, a condition triggered by parasite larvae transmitted by waterfowl that inhabit freshwater lakes and rivers.
Overall Health Impact on Bathers
Despite the elevated relative risks identified in the trial, actual cases of illness remained relatively uncommon among the participants. Gastrointestinal and skin symptoms occurred in roughly 2 percent of the study participants, and the researchers noted that most reported cases were mild and brief.
The International Journal of Hygiene and Environmental Health is a peer-reviewed scientific journal that publishes research on environmental sanitation, water quality, and human health risks. Escherichia coli is a common bacterium used by health authorities as an indicator of fecal contamination, while swimmer's itch, also known as cercarial dermatitis, is a short-term skin reaction caused by microscopic parasites harbored by freshwater birds.
