The world's growing toxic brine problem

Desalination plants around the world are producing far more brine waste than previously estimated and much of it is being dumped into the sea.

A study has warned of rising levels of toxic brine as desalination plants meet growing water needs. (AAP)

The world's thirst for fresh water is causing a salty problem.

According to a scientific study released Monday, desalination plants worldwide are producing 142 million cubic metres of brine daily - about half more than previously estimated.

The report by researchers from Canada, the Netherlands and South Korea claims that would be enough to swamp Florida in a foot of brine every year.

Because much of it is dumped untreated into the sea, and some is laden with toxic chemicals, the authors are calling for better brine management.

Manzoor Qadir, assistant director of the UN University's Canada-based Institute for Water, Environment and Health, said this is particularly important in countries producing large volumes of brine such as Saudi Arabia and smaller neighbouring Gulf states United Arab Emirates, Kuwait and Qatar.

The researchers called for better brine management, noting that studies have shown it can be used in aquacultures to boost yields of salt-tolerant species of fish, and the metals and salts contained in it - such as magnesium and lithium - could be mined.