Future Water Decisions to Be Difficult, Panel Says
Scientists and engineers will face a host of obstacles over the next decade in providing clean water to millions of people caught up in a water shortage crisis, a panel of scientists and engineers said recently at a briefing at the Broadcast Center of the National Press Building on the "Final Report on the American Chemical Society's Global Challenges/Chemistry Solutions."
The American Chemical Society (ACS), the world's largest scientific society, launched Global Challenges in 2008 as a special series of 12 podcasts and Web sites describing how scientists are responding to enormous challenges facing 21st Century society.
The reality today, said Marc Edwards, Ph.D., a panelist from Virginia Tech University, is that the existing plumbing infrastructure is inadequate, and scientists have insufficient knowledge about how to overcome the challenges of providing safe water to people around the world.
Although Edwards stressed the importance of water conservation in meeting those, he also cited unintended consequences of such efforts. He noted, for instance, that reduced-flush toilets and other water conservation methods are allowing water to remain in household pipes longer. As it stagnates in pipes, the water could develop undesirable characteristics and have unwanted effects on household plumbing.
Edwards also detailed how a change in disinfectant from chlorine to chloramine caused leaching of lead into drinking water. A new study by Edwards and colleagues from Virginia Tech University and Children's National Medical Center concludes that hundreds of children in Washington D.C. were introduced to high levels of lead from the city's drinking water. The study will be published in Environmental Science & Technology, one of ACS' 34 peer-reviewed scientific journals.
"The predictions for the levels of lead in water in D.C. from 2001 to 2003 based on prior scientific research were very significant and disturbing," Edwards said. "When the first reports came out finding that there was no detectable harm done, it defied previous scientific understanding. So we did our own study. For the youngest children, those under the age of 1.3 years, you saw substantial increases in blood-lead incidence immediately after switching to chloramine."
Finding appropriate and sustainable solutions to problems like these, said William Ball, Ph.D., from Johns Hopkins University, demands a sharper focus on water-related science. Ball uses computer science to provide a more intelligent way of gathering environmental data. For the last three years, he has collaborated with environmental engineers, hydrologists, and computer scientists to create the Chesapeake Bay Environmental Observatory (CBEO). The CBEO has added to data that has been developed for decades on Chesapeake Bay.
"I disagree with the assertion that the science is understood but we just lack the political will," Ball said. "In fact, we're shy on both fronts, and we need to keep moving forward. The work so far — we're interpolating past data and analyzing past data — reveals that the Bay is even more complex than many might imagine."
For instance, hypoxic zones in the Bay — large areas of low oxygen levels where most animals can't live — are still growing despite lacking the nutrients they need for expansion. "We don't fully understood why that is so," Ball said. "There's a lot to be learned yet about what locations and causes lead to that phenomenon, whether there are carbon sources coming in from the shallows into the deep that current models and understanding don't capture."
Ball urged political action on nutrient reductions, the so-called 'low-lying fruit.' "But we also have to strategize on what the next fruit to pick could be and even what trees to plant, and that takes a lot of planning," he said.
Risk is another factor that takes planning, said Charles Haas, Ph.D., from Drexel University, who specializes in keeping America's water supply safe from terror attacks. "We'll never be in a risk-free environment in water or in any environmental media," he said. Terrorism in general, Haas said, and terrorism in water systems especially are expected to be rare. "So protecting against a rare event is hard, and it's hard to justify on its own in terms of cost-benefit assessments." Haas suggested an emphasis on approaches with dual benefits — not only against terrorism but also for protection of water systems in everyday life.
For example, the use of sensors to detect potentially toxic substances in water could provide general benefits for safety. Cost-effective, low maintenance sensors are a Holy Grail, Haas said, but difficult to develop. He warned that over-sensitive sensors could be counterproductive.
"We need to guard against false alarms," Haas said, likening the situation to a smoke detector responding to a lit match. "That wouldn't be a very good detector in terms of having false alarms. No one has succeeded in developing cheap, low maintenance sensors for water contaminants that could detect low levels of substances and do so with a low probability of a false signal."