Arsenic levels in the Salween River—one of Myanmar’s most vital waterways—have been found to exceed safe limits by more than five times. The discovery, made in December 2025 through joint testing by the Interim Executive Council (IEC) of Karenni State and Chiang Mai University, has raised urgent concerns about the long-term safety of communities that depend on the river.

On February 25, 2026, the IEC issued an emergency warning advising residents not to drink water directly from the Salween or consume aquatic life from the river.

To better understand the scale of the crisis, Sai Harn Lin, a reporter with the Shan Herald Agency for News (SHAN), spoke with an environmental activist about the persistence of toxins, their impact on ecosystems, and the risks facing local communities.

Toxins That Do Not Disappear

Question: Regarding the arsenic and other toxic minerals found in the Salween, how long can these toxins persist—not just in the water, but in riverbed sediment?

Answer:

“Based on the nature of this river, much of the sediment is constantly churned from the bottom to the surface. While the Salween flows rapidly in its main channel, the abundance of rocks and boulders creates whirlpools that push water upward. When this happens, toxins become trapped within the river basin.

Because these minerals settle into the basin, they mix with mud, silt, and sandstone; it is virtually impossible to fully clean them out. Furthermore, cyanide persists in the Salween due to its chemical properties—it tends to remain in cold environments. The Salween’s water is cold, and cyanide tends to accumulate in areas with low heat, which is why it remains in the river today.

As for how it got there, it is due to various mining activities. Minerals are being extracted in the river basin and its tributaries, as well as in upstream areas in China. Even if mining does not take place directly on the Salween, it occurs in streams that feed into it.

As these toxins accumulate, fish in the basin die off. The repeated reports of mass fish deaths and the resulting stench are clear evidence that the river’s biological life is being destroyed.”

A Crisis Without a Single Source

Question: Which mining regions are primarily responsible for this pollution—for example, rare earth mining in northern Shan State or gold mining in the east?

Answer:

“The Salween begins in China, flowing from the Tibetan Plateau in the Himalayas. Significant mining activities are also taking place in China. From the headwaters down, there are communities dependent on the river for livelihoods, including all the tributaries that feed into the Salween.

We cannot point to a single location. Generally, the impact is less visible at the very source. The damage from mining waste and toxins becomes more evident in the middle and lower reaches of the river. However, it is not caused by one factor alone. For instance, in the upper reaches of our region—the Nam Sim, Nam Pang, Nam Teng, and others—waste from those tributaries, including agricultural chemicals, rodenticides, and pesticides, flows into the Salween.

The river is being polluted by a combination of mining activities and chemicals used across the entire basin.”

A River Losing Its Life

Question: What kind of irreversible damage does this toxicity cause to biodiversity and fish species in the river?

Answer:

“When I traveled along the Salween in the past, fish were extremely abundant. I have photos of various species. Now, those fish can no longer be found. While not every individual species will disappear completely, many will inevitably face extinction.

Some may survive in limited areas. Since the headwaters are less affected, fish may migrate between sections of the river. However, if there were once 5,000 species, around 3,000 may already be lost. That is the reality we are facing.”

Health Risks and Uncertain Exposure

Question: How dangerous is bioaccumulation for people consuming crops irrigated with contaminated water or eating fish from the river?

Answer:

“The nature of cyanide is that it cannot withstand heat. If food is properly cooked, it is generally considered safe, as cyanide breaks down when exposed to high temperatures.

Cyanide does not remain stable in heat—it evaporates or disperses. This is different from other heavy metals such as mercury, which can accumulate in aquatic systems.

Many mining processes use chemicals such as cyanide and mercury. Coal and other pollutants can also cause respiratory diseases, including cancer.

Most of the Salween’s toxicity is linked to mercury contamination. It accumulates in cold areas, where aquatic organisms are exposed and die. However, it is difficult to determine exactly how much humans may ingest.

It is also difficult to track cancer rates directly linked to water pollution, as cancer has multiple causes. While a direct connection is hard to prove, skin diseases are likely to appear. Livestock that drink contaminated water may also die.

For example, if a cow drinks polluted water and dies, and people later consume its meat, cyanide would no longer remain after cooking—it dissipates with heat. However, animals living in the river system are clearly being affected, and many native fish species have already disappeared.”

Who Is Most at Risk?

Question: What long-term health risks might local communities face?

Answer:

“One positive development is that many villages along the Salween now use purified water. Small-scale water purification systems are available in many areas, so people are less likely to drink directly from the river.

However, remote communities without access to infrastructure may still be at risk, and they are difficult to reach for medical testing.

The risk depends on water usage. Using river water for agriculture or bathing may not cause immediate illness, but drinking contaminated water poses a higher risk. Fortunately, solar-powered purification systems and bottled water are now more widely available and relatively affordable.

Because of this, it is difficult to predict whether cancer rates will significantly increase.”

A Crisis That Flows Downstream

Question: Will it be difficult for communities to find alternative water sources if the river becomes contaminated?

Answer:

“Yes, it will be very difficult. The communities most dependent on the Salween are in the lower reaches, including Hpapun, Hpa-An, and down to Mon State.

In these areas, the river behaves more like a stream, and riverbanks and farmland are at nearly the same elevation. In contrast, the upper reaches are mountainous, making water access more difficult.

Geographically, there is a significant difference. Communities in the lower reaches face the greatest risk, as they depend heavily on the river for daily life.”

Can Technology Solve the Problem?

Question: Is current water monitoring sufficient to prevent toxicity? What do environmental activists say?

Answer:

“Water can be protected using modern purification technology. For example, experts from Germany have worked on purification systems for Inle Lake. Filtration systems and monitoring equipment have also been installed in some areas.

Modern technology can significantly reduce contamination, even if it cannot eliminate it completely.

However, the challenge lies in scale. A river over 1,800 kilometers long affects an entire ecosystem. It impacts forests, agriculture, and eventually the ocean.

When polluted water enters the hydrological cycle, it can contribute to broader environmental instability. It is difficult to isolate the impact of a single factor, but combined pressures contribute to climate change and environmental disruption.

Changes in rainfall patterns, shorter cold seasons, unexpected flooding, and irregular weather cycles are all part of this broader environmental shift.”

Can the Damage Be Reversed?

Question: If mining stopped today, how long would recovery take?

Answer:

“That depends on policies, management, and long-term planning. The key questions are how waste is managed, how pollution is prevented, and how communities are protected.

It also depends on the scale of extraction and whether raw materials are simply exported or processed into finished products.

Rare earths and other minerals are essential for modern technologies such as electric vehicle batteries. Proper management systems, technology, and environmental laws are needed.

Without these systems in place, environmental degradation will continue rapidly.”

Who Is Responsible?

Question: Who bears responsibility for environmental damage from mining?

Answer:

“Responsibility is shared. First is the actor who opens the door; second is those who carry out the activity. External actors will always come, but the impact is borne by local communities.

Ultimately, responsibility lies with those who permit the activities. Public participation is also crucial, but in many cases, communities are excluded from decision-making.”

A Warning for the Future

Question: What will happen if this continues over the next 5–10 years?

Answer:

“I have worked in environmental protection for 20 years. We have repeatedly warned about worsening conditions before major disasters occurred.

Over the years, we have seen floods, droughts, landslides, and water shortages increase in frequency. Agricultural yields are declining, and weather patterns are becoming increasingly unstable.

These changes may not be obvious year by year, but over five-year cycles, the deterioration is clear. If environmental destruction continues, these impacts will intensify further.”

*This article was originally written by Sai Harn Lin for the Burmese section and translated into English by Eugene.