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".

This is the term used by locals to describe the illegal mining taking place at thousands of sites around the country - including the forested regions famous for their cocoa farms, as well as their vast gold deposits.

The West African state is the world's sixth-biggest gold exporter and the second-biggest cocoa exporter.

Demonstrators recently took to the streets of Accra to demand that the government take action to end illegal mining. The police responded by detaining dozens of protesters accused of holding an illegal gathering. They were later released as anger grew over the arrests.

The hashtags #stopgalamseynow and #freethecitizens were used to galvanise young people across Ghana and the diaspora, particularly in Canada and the UK, to voice their concerns.

Israel Derrick Apeti painting a river scene
On our way to the river, I just thought I could perhaps paint with the polluted water. It just came to me like that. So, we got there, I tried it and it worked out"

Apeti told the BBC that he had decided to contribute to the campaign through art.

"What is art for?" he said, adding: "On our way to the river, I just thought I could perhaps paint with the polluted water. It just came to me like that. So, we got there, I tried it and it worked out."

Communities along the river - one of the biggest in Ghana - lamented to Apeti that the water was "once so clean that you could see the fish and crocodiles that lived in it", but it had been transformed "into a yellowish-brown body of water".

Ghana's music stars have also thrown their weight behind the campaign.

Black Sherif - who hails from Konongo town in the Ashanti region, which has been badly affected by the illegal mining - stopped his set at The Tidal Rave Concert in Accra earlier this month to show a video of the devastation.

Truth Ofori, who was part of Black Sherif's set, then sang a patriotic song called “This is our home”, while Stonebowy used his set to perform "Greedy Men", which targeted those behind galamsey.