Thousands of so-called 'garimpeiros' are flocking to the gold-rich region along the Revue River and its tributaries in western Mozambique. These llegal gold miners hail not only from across Mozambique but also from neighboring countries such as Zimbabwe, Malawi, and Zambia.

Driven by hope for a better life, they pay little attention to environmental protections and related concerns, as they employ toxic chemicals such as mercury, cyanide, and arsenic to extract gold from rock and sediment.

These highly poisonous substances seep into the soil and water during the mining process -- with devastating consequences for ecosystems and local communities.

The Chicamba Dam, the region's most important source of drinking water, and the Revue River are particularly affected by this pollution.

The provincial government of Manica -- which lies in central Mozambique and borders Zimbabwe -- has announced plans to stop informal mining and crack down harder on the garimpeiros; even licensed mining operations will be subject to stricter oversight in response to the growing crisis.

International companies like Xtract Resources plc and Horizonte Minerals plc, both headquartered in the UK, claim to fully comply with environmental standards.

Having held gold mining concessions in Manica for years, they also stress that they pay taxes locally -- unlike the informal miners. Still, these companies are also set to undergo a review.

At a press briefing in early September, Manica governor Francisca Tomas emphasized that environmetal protection was her main concern:

"We must keep our rivers clean and flowing -- not just foragriculture, but for the people who depend on them for drinking water."

The Manica District is home to some of Mozambique's richest gold reserves and has become the epicenter of small-scale mining. But many miners continue to operate outside legal frameworks, disregarding existing environmental laws.

The result is that riverbeds are drying up, the water is turning murky, and many areas are increasingly being blocked with silt -- partly due to weak state regulations and a lack of overall environmental monitoring.

Governor Tomas is calling for regular inspections and a sustainable regulation of gold mining to ensure that natural resources can be used in a way that balances human needs and environmental protection.

But in areas like Mukurumadzi and Penhalonga, where several smaller rivers flow into the Revue, the conditions have worsened dramatically in recent months despite government attempts to intervene.

One illegal miner, Leonardo Beissicopo, openly describes how his method ignores basic environmental concerns:

"First we grind the sand, then we use carpets to catch the gold. After that, we add mercury to bind the gold. And the wastewater flows straight into the rivers," mentioning also the casual use of heavy machinery, drills, generators, compressors, and even explosives in the process.

Another miner, Veloso Elias, meanwhile says that is aware of the risks but adds that he has no other choice:

"We know mercury is harmful to people and animals, but we have no other way to extract the gold."

In an effort to curb unregulated mining, Governor Tomas is now proactively seeking support from traditional and religious leaders in the district.

She says their role is to help raise awareness and ensure compliance with new regulations, while working "together to control the miners and reduce environmental damage."

"We're facing a serious problem. The rivers are polluted, some have already dried up, and the Chicamba Dam is heavily silted," Tomas further explained.

Environmental activist Bernardo Xavier meanwhile warns of dire health consequences if leaders fail to intervene:

"Our rivers are highly contaminated with heavy metals, yet many people have no choice but to drink the water," Xavier stresses, calling for the strict enforcement of ecological standards in the mining sector to safeguard long-term water quality.

But raising awareness among the miners is a difficult task, as most of them live in poverty.

"Their main priority is feeding their families. When authorities crack down, they disappear for a while -- but then they always return. Many come from outside the country, which makes law enforcement even more difficult," says Xavier.

Gold, greed, poison: How miners pollute Mozambique's rivers