Three gold mines are polluting the rivers through the valley with mercury, cyanide and other chemicals, the group said in a report released this year.
From the edition.cnn.com
That produces hydrocarbons and cyanide compounds, which drift downwards and react further to produce a poorly understood group of complex compounds called tholins.
From the newscientist.com
The group led him down to the cellar, where they served him cakes and red wine laced with a massive amount of cyanide.