Authorities have been pushed to new measures in the fight against blue-green algae in South Australia.

Hydrogen peroxide will be added to Torrens Lake in the centre of Adelaide to treat the boorish bacteria.

It signals a ramping-up of the South Australian Government’s efforts to combat the algal assault.

Previously, authorities had been flushing the lake with fresh water, but this led to murky, nutrient-rich water pouring out of the Torrens Outlet at West Beach and into the Gulf of St Vincent.

That technique prompted warnings from the SA Environment Protection Authority for swimmers and beachgoers to stay away from the brown water spotted across kilometres of the cost. 

Trials of hydrogen peroxide have been undertaken in smaller pools alongside the lake, with considerable success.

The EPA hopes that a combination of hydrogen peroxide and fresh water flushing will be enough to keep blue green algae levels to a minimum.

Of course, there are risks to the native flora and fauna, and conservation group Friends of the Earth will be watching closely.

The group admits that hydrogen peroxide can be extremely effective at destroying blue green algae, while leaving other inhabitants untouched.

But it is concerned about the strength and concentration of the acid to be added, especially in regard to animals such as amphibians due to the porous nature of their skin and their ability to draw chemicals into their system very rapidly.