Research – Solar water disinfection effective for E. coli at high, low altitudes


Solar water disinfection (SODIS) may be just as effective at decontamination E. coli-infected water at high altitudes as it is at low altitutdes, according to a press release by Elsevier.

The results of a new study appearing in the Wilderness Medical Society’s official journal Wilderness & Environmental Medicine, published by Elsevier, shows promise this method of disinfection..

Water can be successfully disinfected through several methods: heat, filtration, chemical treatment, and ultraviolet (UV) light. The use of natural sunlight for solar disinfection of contaminated water effectively inactivates many microorganisms, including bacteria, viruses, protozoa, and fungi.

A team of researchers at the University of Colorado Anschutz Medical Campus conducted an experimental study to determine the effect of SODIS on water purification at high altitude (above 2,500 meters) compared to low altitude (below 2,500 meters) among different types of water containers.

“No other published research examining the effectiveness of SODIS at high altitude is available to our knowledge,” said William Mundo, lead investigator of the study. “Adequate access to water, sanitation, and hygiene is a crucial component of human health during emergency situations such as natural disasters and extreme weather events, which are becoming prevalent with climate change.”

A study design previously described in the literature was modified, most notably to evaluate the concentration of E. coli colony-forming units (CFUs) at multiple time points throughout the required six hours of direct sunlight, as recommended by the World Health Organization.

Compared to control containers with no sunlight exposure, the researchers found that all bacteria were inactivated by six hours. At two hours, bacterial inactivation at high altitude was 1.7-fold greater than at lower altitude, however, at the end of six hours, there were no significant differences between high and low altitude samples.

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