In a new paper, an international team of researchers have established that water quality guidelines in North America and Europe do not protect lakes from human-induced salinization, which can have a negative impact on the abundance of freshwater organisms and lake food webs. The increase in salinity of lakes worldwide is largely due to road de-icing salts, agricultural fertilizers, mining operations and climate change. The paper appears in the journal Proceedings of the National Academy of Sciences (PNAS).
“Our study shows the cost of salinization at concentrations currently considered ‘safe,’ illustrating the urgent need to re-examine existing chloride thresholds to maintain the ecological integrity of our lakes,” said University of California, Irvine’s Celia Symons, Ph.D., who ran one of the experimental sites at the Sierra Nevada Aquatic Research Laboratory in Mammoth Lakes, part of the University of California Natural Reserve System.
What’s more, the team determined that a decline in zooplankton caused by the increase in salinity resulted in an increase in algae, which could affect water quality and freshwater fisheries.
To study the effects of increasing salt concentrations on lakes, a group of 16 research teams from North America and Europe ran experiments in parallel as part of the Global Salt Initiative led by Shelley Arnott, Ph.D., from Queen’s University in Ontario, Canada, and William Hintz, Ph.D., from the University of Toledo in Ohio. This large-scale experiment revealed significant harm to freshwater communities at salt concentrations well below water quality thresholds set by regulatory agencies.
“Given that many human activities are increasing the salinity of our freshwaters, it’s critical to understand the ecological consequences of salinization and develop effective water quality management thresholds,” said Symons.
The research team hopes their work will inform new policies by regulatory agencies around the world that ensure better salinization thresholds and protect freshwater ecosystems.
