Climate Change Hurting Water Quality in Rivers Worldwide, Study Finds
Bouts of intense drought and rainfall are hurting water quality in rivers around the globe, according to a sprawling new analysis.
For the study, scientists looked at 965 case studies, tracking how extreme weather impacted rivers on every habitable continent. They found that water quality dropped during 51 percent of floods and rainstorms, as fertilizer runoff poured into rivers and streams.
Water quality also fell during 68 percent of droughts and heat waves. While a drop in flow meant there was less runoff, it also meant there was less water available to dilute contamination, such as pharmaceuticals from urban wastewater. Overheated rivers also had higher levels of salt.
Over the long term, the study found, warming rivers are seeing oxygen levels drop and pollution levels rise. The findings, published in Nature Reviews Earth & Environment, are based largely on data from Western nations. Authors say there is still a dearth of data on the developing world.
“We need a better monitoring of water quality in Africa and Asia,” lead author Michelle van Vliet, of Utrecht University, said in a statement. “Most water quality studies now focus on rivers and streams in North America and Europe.”