Indicators of recreational water quality Because
E. faecalis is a common fecal bacterium in humans, recreational water facilities (such as swimming pools and beaches that allow visitors to swim in the ocean) often measure the concentrations of
E. faecalis to assess the quality of their water. The higher the concentration, the poorer the water quality. The practice of using
E. faecalis as a quality indicator is recommended by the
World Health Organization (WHO) as well as many
developed countries after multiple studies have reported that higher concentrations of
E. faecalis correlate to greater percentages of swimmer illness. This
correlation exists in both freshwater and marine environments, so measuring
E. faecalis concentrations to determine water quality applies to all recreational waters. However, the correlation does not imply that
E. faecalis is the ultimate cause of swimmer illnesses. One alternative explanation is that higher levels of
E. faecalis correspond to higher levels of
human viruses, which cause sickness in swimmers. Although this claim may sound plausible, there is currently little evidence establishing the link between
E. faecalis and human viruses (or other pathogens) levels. Thus, despite the strong correlation between
E. faecalis and water quality, more research is needed to determine the
causal relationship of this correlation.
Human shedding For recreational waters near or at beaches,
E. faecalis can come from multiple sources, such as the sand and
human bodies. Determining the sources of
E. faecalis is crucial for controlling
water contamination, though often the sources are
non-point (for example, human bathers). As such, one study looked at how much
E. faecalis is shed from bathers at the beach. The first group of participants immersed themselves in a large pool of
marine water for four 15-minute periods, both with and without contacting sand beforehand. The result shows a decrease in
E. faecalis levels for each cycle, suggesting that people shed the most
bacteria when they first get into a pool. The second group of participants entered small, individual pools after contact with beach sand, and researchers collected data on how much
E. faecalis in the pool came from the sand brought by the participants and how much came from the participants' shedding. The result shows that
E. faecalis from the sand is small compared to that from human shedding. Although this result may not apply to all sand types, a tentative conclusion is that human shedding is a major
non-point source of
E. faecalis in recreational waters. == See also ==