"Toxic runoff from politically linked gold mine poisons Cambodian rivers, communities", 24 November 2025

… “When you touch the water of the O’Ta Bouk River, the mud will stick to your skin,” said Thao*. “It creates skin issues and we can’t catch fish this year anymore. It’s thick, like condensed milk. The oil from the machinery floats on the water surface, so it might affect our health, like our stomach or intestines.”

On the quiet banks where the Sesan River and O’Ta Bouk River (also known as the Prek Liang River) meet in the northeastern Cambodian province of Ratanakiri, Ta Bouk village is where Thao calls home. The O’Ta Bouk River flows some 90 kilometers (56 miles) through Virachey National Park, one of Cambodia’s oldest protected areas, before feeding into the Sesan River and providing water to Ta Bouk village, just 2 km (1.2 mi) from the park’s border.

The O’Ta Bouk has long sustained the Brao Indigenous communities who live, farm and fish along the river’s banks, providing them with clean, potable water for generations.

But Thao’s village is just one of the hundreds across the Mekong region that have seen their life-giving rivers poisoned by toxic runoff from an explosion of unregulated mining, much of this is driven by surging gold prices, rising demand for rare earth elements and limited government oversight or environmental standards…

Mines choke the region’s rivers

The mines identified by the Stimson Center’s satellite imagery analysis have largely not been confirmed with a visit to the site, or ground-truthed, but can be divided into three distinct types: alluvial mining, heap leaching mines extracting gold and other precious metals, and rare earth element mines…

… In the case of Virachey National Park, the chemical contamination threatens at least 89 species of wildlife found in the park, including clouded leopards (Neofelis nebulosa), gaur cattle (Bos gaurus), endangered Asian elephants (Elephas maximus) and critically endangered Sunda pangolins (Manis javanica). Mining contamination throws the future of both Indigenous communities and threatened wildlife species into jeopardy, but the Cambodian government has so far not responded to the issue, which could flow further downstream if unaddressed.

“The region really lacks expertise in understanding how these chemicals and dangerous elements dilute as they move downstream,” said Eyler, of the Stimson Center. “Some are soluble and others are not. What we do know is that they can contaminate crops as they grow, fish and other biota in rivers, and are directly harmful to humans if consumed or exposed to the skin. A regional effort is required for effective testing and also effective messaging to people who may be exposed.”

Officials from Cambodia’s Ministry of Mines and Energy and the Ministry of Environment could not be reached for comment on the matter.

Testing the water

As the health concerns mount, residents of Ta Bouk village been forced to find alternative sources of water, mostly by digging wells, fearing for their safety should they continue to use the O’Ta Bouk River for drinking, bathing, cooking and agriculture. Their concerns have gone largely ignored by local authorities, who Thao said have visited following complaints but didn’t conduct any testing in the O’Ta Bouk or on its banks. The riverbanks now lay sticky with a mud communities fear is contaminated after water levels rose in the monsoon season.

… Eleven alluvial gold mines and the only heap leaching gold mine identified in Cambodia by the Stimson Center’s data set fall within or in close proximity to a 4,000-hectare (9,900-acre) economic land concession that was awarded to Global Green (Cambodia) Energy Development. Documents seen by Mongabay show the company had previously been granted an 18,900-hectare (46,700-acre) mining exploration license inside Virachey National Park. However, it remains unclear whether Global Green was ever granted the right to extract gold.

Poisonous influence

What is clear is that Global Green is controlled by Try Pheap, an infamous Cambodian tycoon who’s been sanctioned by the U.S. government and has a long track record of illegal logging, along with mining in the Mekong and in other protected forests. Pheap has long enjoyed near total impunity in Cambodia due to his close ties to senior ruling party officials…