Tasmania’s lakes among most contaminated in the world
Mining and waste dumping has badly polluted the lakes, including those in the Wilderness World Heritage Area
Metal contamination levels in some of Tasmania’s lakes are among the highest in the world, a new study has found, while those within the state’s Wilderness World Heritage Area have also been badly polluted by mining.
The Australian National University study found atmospheric metal contaminates from historic mining activities in Queenstown and Rosebery in Tasmania had “contaminated most of the Wilderness World Heritage Area”.
The six lakes studied – including the heritage-protected Dove Lake at Cradle Mountain, Perched Lake, Lake Dobson and Lake Cygnus – were contaminated with lead, copper, arsenic and cadmium.
But the readings for Owen Tarn and Basin Lake – which are on the border of the protected area and closest to the Queenstown mine – were much worse.
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The contamination levels were among the highest in the world, said lead researcher Larissa Schneider, who compared them to highly polluted waterways such as the Kurang River in Pakistan and the Shur River in Iran. The latter had been impacted by waste dumping.
“The levels of contamination are really, really high,” Schneider told Guardian Australia. “There is a case in the US where levels were actually lower than Owen Tarn and Basin Lake and they had serious reproduction problems with the fish there. The levels in Tasmania are even higher.”
Research was needed to determine the impact on fish, algae and bacteria, she said, noting that lead could cause deformities in the offspring of affected fish.
“They need to do research to know what is happening to the fish and if it’s really high … people should not be eating it,” Schneider said.
Dove Lake, at the popular tourist spot Cradle Mountain and the best known of the six lakes, reported high levels of lead that could impact organisms, Schneider said.
The study examined the impact of airborne metal contamination stemming from the introduction of open cut mining in the 1930s until the Tasmanian government created the Environmental Protection Act in 1973.
It found metal contaminants from mining sites at Queenstown and Rosebery as far as 130km away.
“These lakes, they are high, mountainous lakes, they are on top of mountains,” Schneider said. “All the contamination that is reaching these lakes is through atmospheric transport. So you can imagine the level of contamination for the lakes to be at this stage just through atmospheric release.”
However, it was unclear who should take responsibility for pollution caused before the Environmental Protection Act came into effect.
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“The big concern is that the legacy of practices carried out from 1893 until 1994 are still having a negative impact on the environment today and no one is taking responsibility for it,” she said in a statement accompanying the study, which was published in Science of the Total Environment.
The Tasmanian premier, Will Hodgman, said on Friday that the contamination was a “long-standing issue from generations of mining activity that we know now was damaging the environment”.
“We need to take advice as to those responsibilities and where they lie, but I think more broadly there’s a shared, collective responsibility for governments but also for those mining companies now and indeed perhaps those past to be part of remediation,” he said.
Schneider argued the government should ask the mining industry to fund research to investigate the impact of the metal contamination in historic mining sites.
The Department of Primary Industries, Water and Environment was contacted for comment.
https://www.theguardian.com/environment/2019/feb/08/tasmanias-lakes-among-most-contaminated-in-the-world?CMP=soc_567&fbclid=IwAR2eJgetmiklv-r4r6vvf-z387EeamhUugqkWpNDD206SjQPEp1MftSoz5o