Stockholm is the gathering place this week for experts considering the significant challenges of providing safe drinking water in an increasingly urbanizing world. According to the World Water Week website, by 2050 more people will live in cities than are currently living in the entire world (6.8 billion people). The World Bank states that urban centers will hold 95 percent of the global population in the future. Without abundant and safe water, contamination will wreak havoc on urban communities causing frequent illness outbreaks and death.
For urban communities to achieve water security in the future, sheer demand will require water recycling. This will mean treating wastewater as a resource and using a variety of technologies to recover nutrients and energy as well as clean water. In addition a multiple barrier approach is needed for watersheds on the grand scale, which includes protecting raw source water–such as groundwater and surface sources–from contamination, appropriately treating raw water, and ensuring safe distribution of treated water to consumers’ taps.
Pathogens: A moving target
According to a water.org fact sheet, half of the world’s hospitalizations are due to water-related diseases, and waterborne diseases account for 1.4 million children’s deaths each year (see blog). Whether considering emerging waterborne pathogens such as norovirus, E.coli 0104H4 and Cryptosporidium, or ancient ones, including Vibrio cholera and poliovirus, the variety and complexity of transmission of these microbes are a moving target for public health officials. The young, elderly and immunocompromised, which make up one-quarter of the populations of our communities (study), are most at risk.
Recent investigations report that historically, infectious disease became more important after the advent of the urbanization, adding to the evidence that infectious diseases increased throughout the world because of urbanization. Without adequate wastewater and drinking water treatment, outbreaks will continue to occur in the modern world. Haiti is one well-known example. In the United States, the largest waterborne outbreak ever documented impacted an estimated 400,000 in Milwaukee, Wisconsin in 1993. In Nokia, Finland more than 15,000 people were infected with Salmonella and Campylobacter following the contamination of drinking water in 2007.
Scientists at the Center for Advancing Microbial Risk Assessment at Michigan State University have found that water disinfection, such as chlorination, reduces risk to a community for Salmonella (typhoid), Vibrio (cholera), viruses and Giardia (gastroenteritis) by 100 to 1000 times. Yet, if even five percent of the population does not have access to safe water, disease will spread through the populace, simply due to the contagious nature of these waterborne pathogens. Thus, the goal needs to be treated water for all people.
With eyes on the Stockholm conference, we should all think about how we can contribute to smart planning for adequate water demand and good water quality to help meet the needs of future urban populations.
Joan Rose, PhD, is the Homer Nowlin Chair in Water Research at Michigan State University and a member of the Water Quality and Health Council.