Existing water quality guidelines fail to protect lake ecosystems

Irvine, Calif., Feb. 22, 2022 – 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 of the United States of America (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.

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The team also included individuals from Dartmouth College; the University of Barcelona; the University of Quebec in Montreal; Ohio Wesleyan University; Wilfrid Laurier University; Ryerson University; Rensselaer Polytechnic Institute; Ontario Ministry of Environment, Conservation and Parks; Purdue University; University of California San Diego; University of Évora; University of Vic; University of Helsinki; Ontario Tech University; McGill University; Linnaeus University; Uppsala University; Swedish University of Agricultural Sciences; Karlstad University; Montclair State University; Wayne State University; Carl von Ossietzky University Oldenburg; and Lund University. The full list of authors, acknowledgements and support for this research can be found in the published paper.

About the University of California, Irvine: Founded in 1965, UCI is the youngest member of the prestigious Association of American Universities and is ranked among the nation’s top 10 public universities by U.S. News & World Report. The campus has produced five Nobel laureates and is known for its academic achievement, premier research, innovation and anteater mascot. Led by Chancellor Howard Gillman, UCI has more than 36,000 students and offers 224 degree programs. It’s located in one of the world’s safest and most economically vibrant communities and is Orange County’s largest employer, contributing $7 billion annually to the local economy and $8 billion statewide. For more on UCI, visit www.uci.edu.

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