University of Adelaide student, Jacqueline Dupavillon, recently researched the effect of brine discharge on cuttlefish eggs as part of her honours thesis.
Ms Dupavillon found that with the increase in brine concentration, the chance of egg survival decreased and at 50 parts per thousand and above there was total mortality of eggs.
According to Ms Dupavillon heavy metals and toxic chemicals can also be detrimental but “salinity is one of the most important physio-chemical factors to which they are exposed.”
BHP Billiton are currently in the advanced stages of their Environmental Impact Statement for the expansion of Olympic Dam.
Part of the expansion includes a desalination plant, proposed for the Point Lowly Peninsula.
A spokesperson for BHP said the EPA wants brine levels to be within 10 per cent of discharge levels within 100 metres of the outfall.
“This can be achieved because water in the region of Point Lowly is extremely active and helps ensure the rapid dispersion of the return water,” the spokesperson said.
“The dispersion rates have been determined by modelling which takes into account the broad movement of water through the entire gulf and also more detailed modelling of water in the vicinity of Point Lowly.”
According to BHP the desalination plant’s operations will be ‘dwarfed’ by the natural cycles of the Gulf.
“There is an annual cycle where salinties build during summer and fall during winter,” said the spokesperson.
“The plant’s impacts will be well within the natural daily variations of the Gulf, those impacts will be scarcely measurable.”