Getting specific on salts in salinity standards

Getting specific on salts in salinity standards

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An international team of scientists and economists, including IAE Assistant Professor Ben Kefford and adjunct Associate Professor Brenda Dyack, are calling for tougher global salinity regulations to preserve freshwater ecosystems. Their research was published in the prestigious journal Science.

The researchers argue that while salinity standards to protect freshwater life are lacking in most of the world, even where they are enforced they are not sufficient. “Australia and the US are good examples of countries where legislation addresses salinity in freshwater to protect biodiversity, but the existing standards are not clear enough,” says Dr Kefford. “These standards are based on total salinity, and don’t refer to the ionic composition. In other words, the type of salts contributing to the total salinity concentration.”

Ions are as important to salinity as the total salt content, because they can alter the effects of saline water on organisms in those environments. “Waters with the same total amount of salts but different ion composition can have markedly different effects on freshwater life,” Dr Kefford said.

The science of salinisation isn’t the only challenge that needs to be addressed to save freshwater ecosystems. Dr Dyack explains there are complex issues in developing salinity standards, and the need to strike a balance between social, environmental and economic outcomes. “Australia is leading the world in this respect. Unlike the rest of the world, we require ‘triple bottom line’ planning under the Water Act (2007), which governs management in the Murray-Darling Basin,” Dr Dyack said.

“However, we can do more. Specific standards that refer to ionic composition will allow more efficient management of water resources, limit the impact on the wider ecosystem, and deliver greater benefits to communities relying on those freshwater supplies,” says Dr Dyack. “There are a number of approaches that governments could take from our report, including introducing incentives for reducing salinisation,” she said.

The article suggests ways to make it sensible for enterprises to reduce salinity, including wider introduction of market-based cap and trade schemes; subsidies for technology development and implementation; direct economic incentives to commercialise crops that demand less water; and, fees or charges for those releasing wastewater and run-off that contributes to salinity.

The researchers said that the laws governing how such standards are set need to be flexible and developed with a collaborative approach between science, economic stakeholders and other interested groups.