A SCOTTISH loch that was bereft of wildlife after decades of industrial pollution has been declared “back from the dead”.
Scientists have given Kinghorn loch, in Fife, a clean bill of health more than 30 years after populations of fish, birds and insects were wiped out by thousands of tonnes of toxic sludge.
It is believed to be the first example of full ecological recovery following pollution by “red mud”, a manufacturing by-product of aluminium that poses environmental threats around the globe. The sludge consists mainly of iron and clay as well as ions such as arsenic and vanadium that are harmful to humans and wildlife.
“In the 1980s, Kinghorn was effectively dead,” said Dr Bryan Spears of the Natural Environmental Research Council Centre for Ecology and Hydrology, who is the lead scientist on the research project.
“The recovery of plants and animals at the site, includ- ing the impressive fish population, has been remarkable.”
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The pollution started in 1944 when British Aluminium Chemicals Limited — which became Alcan — began using a landfill site above the loch to store red mud. The sludge drained into the loch until 1981, by which time the plant was producing up to 120,000 tonnes of alumina and 160,000 tonnes of red mud annually.
Over the past 30 years, the toxic sludge has been diverted and treated in a waste facility.
The loch is now a thriving ecosystem and haven for giant carp, swans and mallards. A plethora of aquatic plant species have returned, including brooklime and yellow iris.
The presence of chemicals has been closely monitored by the Scottish Environmental Protection Agency (Sepa), providing unique insights into the dispersal rate of water-borne pollutants. They are likely to inform clean-ups in other countries affected by red mud pollution and Spears described Kinghorn loch as “a greatly undervalued scientific resource”.
In October 2010, an aluminium processing plant in Hungary burst its banks, sending a wave of caustic red sludge through nearby villages. Nine people died and many more were hospitalised with chemical burns. Life in the Marcal river, a tributary of the Danube, is said to have been completely wiped out.
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Last year, Amnesty International warned that thousands of families in the Indian state of Orissa faced serious health risks amid reports that heavy rain had caused a vast reservoir of red mud at the Vedanta Aluminium refinery to leach into the surrounding environment.
“The successes at Kinghorn loch are an excellent example of engagement between industrial, regulatory, research, and community groups,” said Ron Edwards, chair of the Kinghorn Loch Users Group. “We have had tremendous co-operation with Alcan and Sepa in fighting the legacy of pollution.”