Amazon Gold Fever Comes with a High Environmental Cost

With gold prices soaring to all-time highs—up more than 400 percent in the last decade, to more than $1,900 an ounce in recent months—market watchers worry where it will end and what the long-term effect will be.

Jennifer Swenson worries, too. But she’s not an economist.

Over the last two years, Swenson and a team of students and colleagues at the Nicholas School of the Environment have worked to document how gold’s stratospheric upward spike is affecting environmental and human health in the resource-rich Amazon lowlands of Madre de Dios, Peru, one of the most biologically diverse regions on Earth.

Miners have eked out meager incomes by digging and dredging for alluvial deposits of gold in Madre de Dios’s river channels and floodplains since Incan times. But the pace of activity has shifted into hyperdrive in the last decade as international gold prices hit new records and newly completed sections of the Peru-to-Brazil Interoceanic Highway opened the region to development.

In April, Swenson’s team published a paper in the online journal PLoS ONE showing that deforestation in parts of Madre de Dios has increased exponentially as miners blast and clear more of the region’s once-pristine rainforest.

The study also found that imports of mercury, used to extract the gold, have risen sharply over the same period. Exposure to the toxic metal, which can escape into the air, soil or water, poses grave environmental and human health risks.

“Today’s record gold prices can carry high environmental costs,” says Swenson, assistant professor of the practice of geospatial analysis. “Unfortunately, some of the world’s poorest people and most threatened ecosystems often end up shouldering a disproportionate share of the damage.”

Images of Destruction

Using NASA satellite imagery spanning six years, coupled with economic analyses of gold prices and Peruvian mercury imports, Swenson and her team calculate that at least 15.2 thousand acres—the equivalent of more than 12,000 football fields—of forest and wetlands have been cleared and converted into bare, mud-streaked swaths of holding ponds and rubble piles at three large mining sites between 2003 and 2009. The areas are plainly visible from space, even with lower-resolution satellite images.

Land cleared for mining has a unique spectral signature on satellite images, Swenson explains, allowing researchers to distinguish it from deforestation caused by farming, road-building or other settlement-related activities.

At two sites, mining deforestation has substantially outpaced deforestation caused by nearby human settlement. Forests disappeared at a rate of 10 football fields a day during 2006-2009, when gold prices rose especially fast.

“In addition to these two large sites, there are many scattered, small but expanding areas of mining activity across Madre de Dios that are more difficult to monitor but could develop just as rapidly,” Swenson says.

Until now, scientists have focused mostly on road building, oil drilling, logging and agriculture as the chief culprits in forest loss, but “this study clearly shows that demand for gold and gold pricing might be another driver—a major driver—of deforestation,” says William Pan, formerly at the John Hopkins Bloomberg School of Public Health and, since fall 2011, assistant professor of global environmental health at the Nicholas School and Duke Global Health Institute.

Most of the deforestation showing up in satellite images is caused by unregulated artisanal miners who are among the most marginalized members of their society.

“There’s no multinational ‘Goliath’ mining company to blame,” Swenson says. “These are poor, small-time miners who do this because they feel they have no alternative. It’s dangerous, backbreaking work, and very few ever get rich.”

These “artisanal” miners often work 12-hour shifts, usually in small groups, for six days at a time. A typical yield is about one gram—or 0.04 ounces—of gold for every 24 hours of work. The take-home pay: About 10 percent of the yield’s actual market value, split among the group.

Most of the miners lack access to modern technology and have limited knowledge of mining’s environmental or human health effects. They rarely have safeguards to limit the release of mercury into the air, soil or water, or to reduce their own exposure to the toxic metal, which is used to bind loose flakes and bits of gold ore into hard chunks that can be more easily extracted, and then burned off with blowtorches once the chunks are in hand.

“The mercury contaminates local water and soil, and ravages the nervous system of miners and their families, but the risks extend far beyond the local area,” Swenson says.

Small-scale gold mining is the second-biggest source of mercury pollution in the world, second only to the burning of fossil fuels. Mercury from artisanal mines can travel long distances in the atmosphere or in downstream surface waters—eventually settling in sediments and moving up the food chain into fish, fish-eating wildlife and humans.

“Virtually all mercury imported to Peru is used for artisanal gold mining. Our study shows that imports have risen exponentially since 2003, mirroring the rise in gold prices,” Swenson says. “Given the rate of recent increases, we project by the end of 2012 mercury imports could increase by more than five times the amount imported in 2009.”

Solutions aren’t easy to come by. The vast size and remote nature of the terrain and the secretive nature of mining has made it difficult for Peru’s government to monitor and control all artisanal mining within its borders.

“Another approach, which could complement monitoring efforts by government and regional environmental NGOs, may be to limit mercury imports to those who have received environmental training,” Swenson says. “Given the harm mercury causes and the fact that we can monitor its entry into Peru, it would at least be a good first step.”

‘What a Concept’

Though Swenson grew up in suburban Sacramento, only an hour or so from the historic California goldfields, and has twice worked for NGOs doing geospatial analysis of land use change and its impacts on biodiversity in South America, she didn’t begin to investigate the environmental costs of gold fever until Cesar Delgado MEM ’08, a former student of hers, sent her newspaper clippings about the Madre de Dios mining deforestation in 2009.

“Cesar said that Peruvians were not expecting this marked increase in gold mining,” Swenson recalls. “I was stunned by how huge it was. And when I searched through the scientific literature, there were no studies documenting the recent deforestation.”

The more she looked into the issue, the more she realized something had to be done. Located in the western Amazon, Madre de Dios is thought to host some of the highest numbers of mammal, bird and amphibian species in the world, and is home to some of the Amazon’s largest remaining swaths of virgin rainforest. Animal and plant life there is so diverse that Peruvian law proclaims it to be the world’s “Capital of Biodiversity.”

Swenson enlisted Catherine Carter, an MEM student in her remote sensing class, to help unearth data and images of what was happening in Madre de Dios. (Carter graduated in 2010 and now works at Tetra Tech Inc. in Research Triangle Park.) As the project grew, Swenson also enlisted the help of her husband Jean-Christophe Domec, a research associate in forestry at the Nicholas School.

“We had no funding. We did the research mostly on weekends. And our topic was about as far off most policymakers’ radar screens as the part of Peru we were studying,” Swenson says. “I wasn’t sure anyone outside a small circle of conservationists would even be interested.”

While on sabbatical in spring 2011, Swenson submitted the paper to PLoS One, the Public Library of Science’s online peer-reviewed journal, and crossed her fingers.

“I had no expectations,” she says. It wasn’t until after the study’s publication, when reporters and conservationists on four continents began contacting her, that Swenson realized her team’s “little paper” might have struck gold. Friends called to say they heard her on NPR, saw the story on MSNBC, or read about it on science and conservation websites from India to Indianapolis. Domec, who was in France at the time, sent her updates on how it was playing in the European press. Delgado reported on the reaction in South America.

“It’s the first time in my career this has happened, and it was a little overwhelming at first,” Swenson says with a grin. “But it finally got to a point where I sat back, took a deep breath and realized, “Wow, we might actually influence policy. What a concept.’”

Like her team’s paper, Swenson’s career has, at times, progressed along a somewhat nonlinear trajectory.

Growing up in a family where there were more hiking boots than high heels, she developed a love of the outdoors early, but it wasn’t until high school that she began to think of the environment as a possible career field.

“I had this wonderful environmental studies teacher who was dynamic, creative and kind of wacky,” Swenson recalls. “She planted the seed and inspired me to enroll at the University of California-Santa Barbara to study geography and international relations.”

Shortly before graduating from Santa Barbara, Swenson took her first geospatial analysis class and saw her first satellite image. “It was like a new window opened on the world,” she says.

Unfortunately, she knew one class wouldn’t be enough to open job doors.

Determined to learn more, she volunteered after graduation at the National Park Service’s regional GIS center in Colorado and made ends meet working a variety of seasonal jobs, from being a bike tour guide in summer, to waiting tables and driving a UPS truck in winter.

Swenson enjoyed the practical focus on her duties at the park service, but it soon became clear that to achieve what she really wanted—“to immerse myself entirely in ecology and geospatial analysis”—she had to return to school. She enrolled in the geography program at San Diego State University and graduated with a master’s degree in 1995.

This time, she had the skills to land a great job.

“Immediately after turning in my master’s thesis, I got on a plane for South America for a job doing tropical land-use-change analysis as a geospatial lab manager at EcoCiencia, an Ecuadorian NGO,” she says. “We looked at issues such as the conversion of primary forest into agriculture and the impacts of oil drilling in the Amazon and colonization around new roads.”

The work was all Swenson had hoped for, but the more she learned about the issues threatening ecosystems and communities in South America, the more she realized “I needed to know more about the underlying ecology and science.”

After three years, she returned to the States to get a PhD in forestry ecology from Oregon State University. She finished her dissertation in 2004 and—once again—found herself pondering her career path.

“I was a bit torn,” she says. On one hand, a career in academia would offer a chance to do meaningful research and teaching; on the other hand, working at an NGO would provide the practical, real-world focus she found so satisfying. “The all-too-frequent disconnect between academia and on-the-ground environmental problems has always been disconcerting to me,” she explains.

After testing the waters at the U.S. Forest Service and the conservation NGO NatureServe in Washington, D.C., Swenson realized there was a third path open to her, too. In late 2006, she accepted a post as assistant professor of the practice in geospatial analysis at the Nicholas School.

“Assistant professor of the practice,” she says. “I liked the sound of that.”

Striking Gold

Five years later, Swenson remains confident she made the right choice. “This position is the perfect platform for me—it links the applied environmental interests of our fantastic master’s students and the research from our outstanding academics,” she says.

This fall, she’s teaching two graduate-level classes, supervising multiple masters projects, advising dozens of MEM (Master of Environmental Management) students—there’s nearly always a line waiting outside her office door—and has taken on new responsibilities as the school’s director of professional studies. Over summer, she co-directed a Duke Engage undergraduate outreach project in Ecuador with fellow assistant professor of the practice Elizabeth Shapiro.

On the research front, Swenson’s applying her geospatial expertise to a wide range of real-world issues, from endemic species and ecosystem mapping in the Peruvian and Bolivian Amazon, to forest change in the southern United States. She has a PhD student, Mariano Gonzalez-Roglich, who is conducting NASA- and NSF-funded research on the effects of broad-scale shrub encroachment in Argentina. And she hopes to collaborate other faculty members on further remote sensing studies in the tropics, including a follow-up to her PLoS ONE paper.

“I’m busy—but good busy,” Swenson says. “As an assistant professor of the practice, my primary responsibilities are teaching and advising, which I love. But I definitely want to continue carving out time for research. It’s the balance I’ve been looking for: science, applications, and students.”

Tim Lucas is the Nicholas School’s national media relations and marketing specialist.