Is it safe to go back into the water?
The association between bathing in recreational waters and the risk of illness has been the subject of many epidemiological studies since the 1950s. A large number of these investigations report that exposure to water contaminated with faecal material increases a person’s risk of illness, particularly symptoms of gastrointestinal illness.However, not all studies report such results and the evidence that bathing increases a person’s risk of illness is still uncertain. There is a perception among policy-makers in high-income countries that the risk of ill health associated with bathing is negligible, since many high-income countries report high rates of compliance with bathing water quality regulations.
Many countries regularly monitor bathing waters for these FIOs to ensure that levels of faecal contamination are not high enough to pose an excess risk to bather health, as recommended by the World Health Organization. However, the cost of this activity restricts the agencies responsible for monitoring bathing waters to testing samples taken from a limited number of bathing waters during periods of high use (commonly called ‘the bathing season’). Due to the large spatial and temporal fluctuations in FIO densities that occur in natural waters, weekly measurements are unlikely to capture high levels of faecal pollution that occur in between samples. A number of recent studies have reported that even in bathing waters that were considered to be of good quality (containing low levels of FIOs), bathers were still at an increased risk of experiencing gastrointestinal illness, along with respiratory infections and ear and eye ailments.Therefore, it is useful to know what risk of illness people face when they bathe in natural waters, regardless of the timing or levels of FIOs.