Study confirms high mercury levels in Loddon

EPA officers use electrofishing techniques in Big River as part of a study into Victorian waterways.
EPA officers use electrofishing techniques in Big River as part of a study into Victorian waterways.

Related: Fish consumption advice issued for Loddon River

HEALTH warnings on fish caught in the Loddon River will remain in place after the Environment Protection Authority this week published a study on the impacts of gold mining on Victorian waterways.

The study, released on Monday, showed all tested areas of the Loddon exceeded the minimum mercury levels, while testing at Bridgewater campsite showed high levels of mercury in fish.

Further testing led to a health warning urging pregnant women and young children to avoid consuming more than one fish per fortnight caught between Laanecoorie Reservoir and Bridgewater. The health warning was released in April and remains current.

The heightened mercury levels were detected in redfin perch and carp, and were suspected in Murray cod and golden perch.

The EPA study recommended further investigation of other fish species in the river, and further studies on waterways across the state.

“Consideration should also be given to the need for investigation of other fish species present in Loddon River that may also accumulate elevated mercury concentrations,” the report read.

“It is highly likely that historical mines, which can remain significant sources of pollution for many years, are the source of these contaminants.

“The occurrence of gold mines in the upstream catchment may therefore be used to identify additional streams in Victoria that are likely to be affected by historical mining pollution.”

Arsenic levels were below the minimum safe level for the Loddon River.

The study tested mercury and arsenic levels in nine Victorian waterways, including the Coliban River where no heightened levels were detected.

The Big River and Sailors Creek also contained heightened mercury levels and required further investigation.

Mercury was historically used to help extract gold from crushed ore and was poorly managed, allowing it to be retained in dams or released directly into water streams.

The effects of mercury contamination is primarily on developing central nervous systems, meaning young children and pregnant women are most at risk.

The study focused on the effects of gold mining on the recommendation of three catchment management authorities and the EPA.