http://www.abc.net.au/news/2015-10-19/researchers-discover-a-way-to-remove-mercury-from-water/6865462

http://www.abc.net.au/news/2015-10-19/researchers-discover-a-way-to-remove-mercury-from-water/6865462

I wonder how they came across it? I guess the colour change might have been a clue...
http://www.abc.net.au/news/2015-10-19/researchers-discover-a-way-to-remove-mercury-from-water/6865462