Water from a polluted river in Ghana was so thick and discoloured that an artist was able to use it as paint to depict the environmental devastation caused by the illegal gold mining that has spread like wildfire in the resource-rich West African state.

Mercury is increasingly being used to extract gold by miners digging on a massive scale in forests and farms, degrading land and polluting rivers to such an extent that the charity WaterAid has called it "ecocide". "I could actually paint with the water.

It was so bad," Israel Derrick Apeti, better known as Enil Art, told the BBC.

He and his friend Jay Sterling visited the Pra River - around 200km (125 miles) west of the capital, Accra - to make a point about the environmental catastrophe unfolding because of "galamsey".