Students will travel to South America to study sustainable small-scale gold mining practices to prevent mercury contamination

Dallas, Texas (SMU) – SMU environmental engineering students will search for new sustainable methods for small-scale gold mining in Colombia with the help of a $450,000 three-year grant from the National Science Foundation. Their work will explore the prevention, remediation and restoration of contaminated environments where mining is key to residents’ livelihood, says Kathleen Smits, professor and chair of civil and environmental engineering at SMU’s Lyle School of Engineering.

Artisanal and small-scale miners – the term for individual miners, families or small groups with minimal or no mechanization to do the work – sift through rocks in rivers and dump beads of mercury over the sediment, which clings to gold. They then light a match, using the flames to separate the mercury from the gold, a process that shoots toxic vapors into the air.

It’s an inexpensive method of mining gold, but mercury leaks into the air and pollutes water systems downstream.

The mercury causes severe health problems for miners and those who consume the crops and fish it has contaminated.

“Mercury contamination is perhaps the greatest environmental hazard associated with small-scale mining, given the risks of exposure to this toxic metal,” Smits says. “However, from the perspective of miners and their communities, while many are aware of these risks, social, cultural and economic factors also play a significant role in determining mercury’s danger.”

Mercury from mining has broad impact

Students are tackling an overwhelming problem – small-scale mining provides almost 20 percent of the world’s gold. Artisanal mining is the livelihood of 15 million people, half women and children, in 70 countries, according to the United Nations Environmental Program. Yet, its environmental and personal health consequences are severe. Small-scale gold-mining releases 40 percent of all mercury pollution to the environment and those who mine it face life-threatening mercury poisoning.

“It’s crucial to help students understand that the goal of this project isn’t to solve all the problems associated with this activity but to make small steps toward more sustainable mining practices,” Smits says.

In the spring 2025 term, the grant will support the pairing of SMU environmental engineering and sustainability students with students from Colorado School of Mines. Together they will begin a year-long research experience culminating in a summer stay at the University of Colombia in Medellin, Colombia, where they will examine sustainable mining practices both in the field and in university labs. Students will then continue to make progress on their research topics through engineering and sustainability capstone design courses in the fall term.

The student research will be grounded in the social context of the mining communities. Their work builds upon a six-year project by the collaborating schools seeking engineering solutions to environmental problems, all in context and alongside the miners whose lives are both sustained and threatened by gold mining, Smits says.

Mercury contamination levels need clarification

Smits, who has long studied issues relating to mercury contamination, spoke in November 2023 at a meeting of the delegates (COP-5) of the United Nation’s Minamata Convention on Mercury in Geneva, Switzerland. Her study of baseline mercury emissions reported by 25 countries, published in March 2023 in the journal Environmental Science and Policy, revealed that the reporting process was not sufficient to provide the kind of baseline emission data necessary to make effective mercury emission policies and interventions. 

Smits joined SMU’s Lyle School in 2022, bringing key research interests in water, energy and the environment, specifically land-atmosphere interactions, greenhouse gas emissions from infrastructure and the integration of sustainable environmental remediation and local knowledge. The recent grant, from the NSF International Research Experiences for Students, funds a new program that is part of a six-year collaborative project between SMU, Colorado School of Mines and University of Colombia in Medellin, Colombia.