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The Poisoning of the Amazon

By: Jacqueline Gerson, Kelsey Lansdale and Melissa Marchese The pitter-patter of rain echoes through our metal boat as we chug down the Madre de Dios River in the Peruvian rainforest. Trees line the riverbanks, just visible through the dense fog and heavy rain, while macaws and capuchin monkeys screech in the background; the Amazon is...

By: Jacqueline Gerson, Kelsey Lansdale and Melissa Marchese

The pitter-patter of rain echoes through our metal boat as we chug down the Madre de Dios River in the Peruvian rainforest. Trees line the riverbanks, just visible through the dense fog and heavy rain, while macaws and capuchin monkeys screech in the background; the Amazon is just as we had envisioned.

But we are not your average tourists, birdwatching on an Amazonian tributary — we come equipped with an entire boatload of supplies to conduct research: 55-meter-long PVC pipes, six coolers, two enormous duffel bags, two large boxes and three camping backpacks. We are here to investigate something that is normally hidden from visitors yet is one of the largest environmental and human health disasters to plague the region: mercury contamination from artisanal and small-scale gold mining (ASGM).

Gold and other precious metals have been mined and exported from Peru’s resource-rich landscape since Spanish colonization began in the 16th century. In the last twenty years, gold mining specifically has become increasingly popular, offering promises to men from all over the country to “strike it rich” by mining this in-demand and profitable commodity. The mining practice continues to expand despite being completely illegal. The reason behind gold-mining’s success? Mercury. ASGM uses large amounts of this potent and dangerous pollutant to effectively extract gold from sediment. Mercury usage, in turn, spells lifelong health consequences for residents and wildlife, plays a large role in deforestation, has radical social effects and causes detrimental environmental contamination.

During the first few days of our adventure, the impact of ASGM remains invisible to us. Instead, we happily soak in the astounding beauty of the forest and the sincerity of its people. During our first stop along the Madre de Dios River, as we climb the steep mud stairwell from the boat to the small town of Boca Manu, we are greeted by delicious food, kind people and magnificent rainforest.

Yet, even on land, our view of all the activities occurring on the river in front of us serves as a reminder of how interconnected the people are with the water that runs by their town. In an effort to better understand this relationship, we ask a group of children to illustrate what the river means to each of them. Almost all of their drawings show a heavily forested riverside with a winding, clean river; large fish swim in the water, birds flit above it and people paddle across its smooth surface. The river they draw — the one they intimately know — is a river that provides the population with food, transportation and tourism revenue.

Yet, moving downstream on the Madre de Dios River, the landscape suddenly begins to deviate from the picturesque body of water depicted by the children. ASGM’s presence is very clear, ravaging the shores for hundreds of miles. First, dense old-growth forests are replaced with younger stands that struggle to grow after the rampant deforestation associated with ASGM (deforestation stems from mining camps, illegally built roadways and the mining itself). Then we begin to see large pyramidal mounds of rocks hugging the shoreline. Sometimes a pile stands alone, isolated from other pyramids. Other times they are found by the dozens, one beginning at the tail of another. As we stare at these piles of displaced rocks, we notice men poking their faces out of the water as they angle tubes into the sediment, and other men preparing the engines that rest on wooden platforms above some of the piles — these are the active mountains of rocks, formed as miners extract gold from the river in the process of ASGM.

The piles of rocks littering the river are not the only evidence of mining activity in this area. As we pass the Colorado River, home to one of the larger mining towns, a visible mixing of water occurs with the Madre de Dios River. The Colorado River has a drastically different coloration than the blue of the Madre de Dios — it is an opaque chocolate brown. The suspended sediment loosened by the gold extraction process has given the river this color, so its name, “The Colored River,” is fitting. We watch as the Colorado River slowly turns the Madre de Dios River from its deep blue to a caramel brown — spreading the impact of ASGM to the entire ecosystem.

When we finally reach the shore of Boca Colorado, we feel as though we’ve entered the Wild West. All eyes are immediately on us, the obvious foreigners and only females wandering the streets, but we are not the only outsiders in town. Most of the men here have traveled from faraway cities, such as Cusco and Puno, and reside here without their families for several months of the year. In a country where culture is shaped by regional norms that have formed over centuries, this influx of transient migrants disrupts established social patterns. The miners come with a burning desire to become rich overnight, a general disregard for the dominant Amazonian culture, a lack of family to care for and a bachelor style of living. As a result, prostitution, heavy drinking and crime have become commonplace, particularly in the Red District area near the center of town, and a general sense of mistrust pervades what was once a tightknit community. It is not only the people that remind us of the mining activities, but also the infrastructure we observe. Nearly every store either buys the gold produced from ASGM or caters to it in some way: hardware stores specialize in mining equipment (tubing, diesel engines, etc.), general stores are lined with rubber boots for trekking on the mucky shores, and restaurants open early to serve hearty breakfasts to miners. Gold mining in Peru may be illegal and subject to periodic government crackdowns, but the local businesses in this town help perpetuate the practice.

The scale of mining operations ranges from a small group of men equipped with a diesel engine to larger groups with barges and heavy construction equipment, but the processes and results are essentially the same. In ASGM, miners work in a team to pump sediment from the river and then pass these slurries through a gravity filter — rocks and heavy particles are discarded back into the river, forming the mountains of rock we see. The remaining fine particles cascade down a wooden board covered with what looks like a rug. The dense gold particles get stuck in the threads of the fabric, while water and other sediment are washed back into the river. The cloth is then removed and dunked in an oil drum to begin the process of isolating the gold particles. At this point, mercury is added to bind selectively to the gold, separating it from other sediment particles. This mercury-gold amalgam is then retrieved and the mercury burned off, leaving behind gold that can be sold in town. Any mercury-rich tailings that remain in the oil drum are dumped directly into the river.

While groups of miners can produce up to 30 grams of gold per day using this process (worth an astounding US$600), their actions are altering the river’s flow, disturbing local cultural norms and introducing large amounts of toxic mercury into the environment. In fact, the Madre de Dios region of Peru is estimated to produce 16 tons of gold per year, using over 32 tons of poisonous mercury in the process. Once in the air and water, mercury is a potent toxin that can impact the neurological functions of people and animals, particularly carnivorous species that feed high in the food web. It is these environmental and health impacts of mercury that brought us on this journey.

The effects of ASGM on forests and wildlife are not isolated to the area around Boca Colorado. As we continue downstream to the regional capital of Puerto Maldonado, the river is lined with eroded streambanks, gaps in the forest canopy and endless mountains of rocks. In Laberinto, a day’s trip downstream from Boca Colorado, we dock our boat on a deteriorating shoreline that is slowly dumping abandoned edifices into the river as the sediment banks crumble. We are greeted by a towering sign proudly advertising “Amazon gold” (a gold-buying shop) and other stores selling the standard rubber boots, pumps, tubing and cloth needed for the mining process. The entire region has been transformed by ASGM.

Only after witnessing the harsh realities of ASGM from the river and in mining towns such as Boca Colorado do we fully realize the effects mining has on the communities upstream. When we first arrived in Peru, we were mesmerized by the beauty and serenity of the Amazon — the trees, birds, animals and people. During the first few days of our trip as we journeyed to Boca Manu, the forest seemed untouched by ASGM, but the impacts of mining do reach even these upstream communities and wilderness areas. Mercury released through burning the mercury-gold amalgam travels through the atmosphere to be deposited in areas far from its source, fish that migrate through the river are now scarce due to the high sediment loads associated with mining, and gold-rush newcomers from other areas of Peru bring alcoholism and crime to remote areas, disrupting the established social norms of indigenous Amazonians. The scene we witnessed near Boca Colorado is becoming the standard as mining activities continue to increase. Everyone must try to adapt to this new Peruvian Amazon.

Even though we are studying the impact of mercury on the environment, we also witnessed how the tradition of ASGM and the toxin itself are leading to neurological impacts on the people and changing the interactions of people as a whole. At moments in our journey, it seemed that only by developing superpowers (as suggested by our boat guide Ramiro) could we stop the illegal and omnipresent practice of gold mining. While we obviously wish for superpowers, we choose a more realistic pathway for change. We strive to use scientific research to promote an improved understanding of the environmental, health and social impacts of mercury used in ASGM and to induce policy reforms that benefit this unique environment and its people.

Jacqueline Gerson, Kelsey Lansdale, and Melissa Marchese are students at Duke University. Duke University has provided funding for their research through a Bass Connections Project and a Center for Latin American and Caribbean Studies grant.

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Voices for Biodiversity
An online magazine connecting humans with the natural world to help all species survive and thrive together. Voices for Biodiversity shares the stories of eco-reporters from around the world, using the ancient human art of storytelling to connect people with each other, other species, and the natural world. Our goal is to connect the human animal with the global ecosystem.