Despite enormous strides in water quality testing and treatment during the last 150 years, many people still lack access to safe drinking water. And time is running short. With the United Nations Sustainable Development Goals calling for safe drinking water for everyone by 2030, researchers and policymakers need to do more, according to Mark D. Sobsey, the recipient of the 2016 NWRI Athalie Richardson Irvine Clarke Prize for excellence in water research. He gave a lecture (Advances and Innovations to Achieve Microbially Safe and Sustainable Water: Detection, Treatment, and Risk Management) on advances in water quality testing and treatment at the Annual Clark Prize Award Ceremony, held by the National Water Research Institute (NWRI) on November 3 in Newport Beach.
Sobsey was the Distinguished Professor of environmental sciences and engineering at the Gillings School of Global Health at the University of North Carolina at Chapel Hill and the 23rd recipient of the $50,000 (USD) Clark Prize, given annually to recognize research accomplishments that solve real-world water problems. Trained as a microbiologist and environmental health scientist, Sobsey has worked extensively on detecting and controlling waterborne viruses and bacteria. In his lecture, he outlined the progress that humanity has made in ensuring clean, safe drinking water, and recommended several additional steps that would ensure safe drinking water for all people, including those in developing countries.
It was only in the mid- to late-1800s that scientists using microscopes, filters, and visual staining techniques were able to link certain recognizable diseases, such as typhoid fever, cholera and bacterial dysentery, to fecal contamination of water and inadequate sanitation, Sobsey said. Scientists recognized Escherichia coli (E. coli) as a convenient indicator bacterium for fecal contamination in water. Water quality standards governing bacteria levels came into use in the early 1900s and are still used today.
Normally, water managers use central treatment systems to clean water from aquifers and reservoirs before conveying it to customers in closed, protected systems. But such centralized distribution systems are unavailable to many people in developing countries. Household water treatment and safe storage methods could help fill the gap, according to Sobsey.
People have treated water at the point of use for centuries, usually by boiling, settling, or filtering. Modern treatments, such as adding chlorine, are available in the developed world, but often not in developing countries. Increasing the adoption of household water treatment systems could increase access to safe drinking water. Particularly effective are microporous filters, such as ceramic pots and biosand filters, that do not require chemical additives and work continuously.
Viruses in human fecal waste have long been known to pose a significant threat to water sources and human health, but detecting them is difficult because of low concentrations and contaminating microorganisms, Sobsey said. Although advancements have been made in testing techniques, testing for all waterborne human enteric viruses that people shed in their fecal waste is still impractical. Fortunately, a group of fecal indicator viruses – coliphages, which infect E. coli bacteria – exists and functions similar to the way E. coli acts as a fecal indicator bacterium for pathogenic bacteria. Effective methods to test for coliphages in water already exist, but are not widely used.
Sobsey recommended increasing testing for both waterborne viruses and bacteria to, for instance, identify the bacterium that causes cholera. Researchers also should work on improving treatment methods. One promising method is the use of chitosans, which are chemical derivatives of the chitin from crustacean shells. Lastly, scientists should search for antimicrobial-resistant enteric bacteria in wastewater to determine their potential to cause infections.
More information about the Clarke Prize, including downloadable copies of the 2016 Clarke Lecture, is available at the website.