Did you know that several countries, such as the Maldives, Malta and the Bahamas, meet all their water needs through the desalination process—that is, they convert seawater to freshwater?

Oceans cover 70 per cent of the planet. They provide nourishment for over three billion people and absorb 30 per cent of carbon dioxide released into the atmosphere and 90 per cent of the heat from climate change. Increasingly, they are also providing freshwater for a burgeoning population.

While there’s no shortage of seawater, it’s important to understand and monitor the impact of the rapidly growing number of desalination plants on the environment. Desalination is the process of removing salts from water and a by-product of the process is toxic brine which can degrade coastal and marine ecosystems unless treated.

In most desalination processes, for every litre of potable water produced, about 1.5 litres of liquid polluted with chlorine and copper are created. When pumped back into the ocean, the toxic brine depletes oxygen and impacts organisms along the food chain.

“Increased salinity and temperature can cause a decrease in the dissolved oxygen content, resulting in conditions called hypoxia,” says Manzoor Qadir, Assistant Director of the United Nations University Institute for Water, Environment and Health (UNU-INWEH).

This can harm organisms living on or in the bottom of a water body and translate into observable effects throughout the food chain. In addition, certain compounds (e.g. copper, chloride) used in the desalination pre-treatment process can be toxic to organisms in the receiving water, according to Qadir.

Saudi Arabia (population 34 million) gets about 50 per cent of its drinking water from desalination.

A 2018 United Nations study says th