Arsenic-cleaning bacteria discovered in mine

Scientists have discovered new types of bacteria that can clean up arsenic spills at temperatures near freezing and could hold the key to developing a living sensor for arsenic contamination.

Forty years of gold mining at the site has left a legacy of massive arsenic contamination

Forty years of gold mining at the site has left a legacy of massive arsenic contamination

The researchers were studying arsenic pollution in the Giant Mine, in Canada, which holds more than 230,000 tonnes of arsenic-containing dust.

But they found that the walls of the Giant Mine - a former gold mine in the sub-arctic region of Canada - were home to a previously-unknown bacteria that was cleaning arsenic from polluted water.

The findings were revealed to the Society for General Microbiology, at a meeting in Trinity College, in Dublin, on Monday.

"Water seeps through the mine cracks carrying the arsenic with it as it drips down the walls," Thomas Osborne, from University College London, said.

"We discovered new types of bacteria living in biofilms on the walls of Giant Mine that consume arsenic compounds contained in the polluted water seeping through."

It is the first time scientists have identified bacteria that can deal with arsenic contamination at such low temperatures.

"The new bacteria we discovered function at temperatures from 20 degrees Celsius down as low as four degrees Celsius," Mr Osborne said.

He added: "The other exciting possibility that this opens up is that we can isolate the enzyme from these new strains of bacteria and develop an arsenic biosensor to use in cold environments.

"This will warn when traces of arsenic are escaping from areas like mine workings, industrial chemical facilities, or even laboratories, alerting us before pollution manages to get into watercourses or drinking water supplies.

"We could also use it to test newly drilled wells in countries like Bangladesh where water supplies are known to be contaminated."

Most organisms, including all plants and animals, ultimately get their energy from sun.

However, these new bacteria are among a growing group of microbes that scientists have discovered that can get their energy directly from breaking down chemical bonds, allowing them to survive in the most inhospitable environments.

Kate Martin



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