Impacts of Artisanal Gold Mining on Humans and the Environment (2023-2024)


Artisanal and small-scale gold mining (ASGM) is the world’s single largest source of mercury pollution originating from human activity. Millions of miners add elemental mercury to gold-bearing ores or sediment to extract the gold, generating mercury emissions and waste that pollute air and water. ASGM is responsible for roughly 85% of the gold produced in Ecuador with the Puyango-Tumbes river basin as the oldest mining region in the country. 

Historically, hardrock ores containing gold and other heavy metals such as lead and arsenic were crushed and processed with mercury and cyanide to extract the gold. Metal and cyanide-contaminated residuals were then discarded into the river, which rendered the river uninhabitable for many aquatic species and largely unusable for people. Although mercury was banned in Ecuador in 2013, no follow-up research on water and sediment quality has been conducted to determine the efficacy of the 2013 ruling on continued mercury use. 

Improved environmental regulations along the Puyango-Tumbes may also inadvertently exacerbate mercury toxicity to people and the ecosystem. In low-oxygen environments, inorganic mercury can be converted by microbes to the highly toxic and bioaccumulative organic form of mercury — methylmercury. Cyanide suppresses the microbial communities that generate methylmercury. Tighter restrictions on cyanide loading may promote the methylation of historically deposited mercury, threatening both the ecosystem and human health.

Project Description

The goal of this project is to assess the extent of environmental degradation and human and ecosystem exposures to heavy metals from artisanal and small-scale gold mining in Ecuador. Building upon an ongoing collaboration between researchers at Duke and the University of San Francisco-Quito, this team will be divided into three subteams with the following aims:

  1. Environment: Determine the efficacy of the mercury ban in the Puyango-Tumbes basin and impacts of new mining activity in the Napo region by evaluating seasonal mercury distribution in the watersheds and land cover change using satellite imagery.
  2. Epidemiology: Measure mercury, lead and arsenic exposures and associated health impacts among people living in the Puyango-Tumbes watershed through hair, blood and urine collection.
  3. Policy: Coordinate with United Nations Development Programme to align human and environmental sampling with planned interventions to evaluate whether the adoption of new technologies and new processing methods has an impact on environmental and human health.

Anticipated Outputs

Peer-reviewed publication; data on mercury contamination in Puyango-Tumbes basin following 2013 mercury ban; identification of contaminant hotspots

Student Opportunities

Ideally, this team will include 4 graduate and 4 undergraduate students with a range of technical skills (e.g., remote sensing, geochemistry, field work and policy analysis). For students that intend to go into the field, an intermediate level of Spanish is preferred. 

Applicants may come from a variety of disciplines, such as environmental management, chemistry, biology, engineering, public policy or law. Students interested in South American policy, field research and popular science writing are especially encouraged to apply.

Members of the team will engage in immersive experiences in the lab and field and work with multiple stakeholder groups, including the communities directly affected by mining, policy makers from the UN and scholars from other institutions. Students will be able to affiliate with one or more subgroups, according to their interests, and will be encouraged to develop honors thesis projects, present results at conferences and improve their scientific writing by contributing to peer-reviewed manuscripts.

The team has optional summer components in the summers of 2023 and 2024. Some team members will travel to Ecuador during the winter break of 2023-2024.

Shannon Plunkett and Danny Tobin will lead the environmental and policy subteams. The team will recruit another student to manage the epidemiology subteam.


Summer 2023 – Summer 2024

  • Summer 2023 (optional): Begin geochemical analyses of previously collected samples
  • Fall 2023: Begin geospatial analysis; complete geochemical data processing; prepare for winter field work
  • Spring 2024: Complete geospatial and environmental sample analysis
  • Summer 2024 (optional): Develop reports and manuscripts to disseminate results to partners and academic journals


Academic credit available for fall and spring semesters; summer funding available

See earlier related team, Field Testing a Mercury Capture System for Artisanal Gold Mining (2021-2022).


Image: Helena Frischtak, M.D., conducting cognitive assessment tests (Woodcock-Munoz) on children in the Peruvian Amazon, from 2021-2022 team poster

Woman seated outdoors at a table, with a green parrot on her shoulder, points to a place on a paper while a seated boy looks on.

Team Leaders

  • Heileen Hsu-Kim, Pratt School of Engineering-Civil & Environmental Engineering
  • William Pan, Nicholas School of the Environment-Environmental Sciences and Policy
  • Shannon Plunkett, Pratt School of Engineering–Civil and Environmental Engineering–Ph.D. Student
  • Daniel Tobin, Nicholas School of the Environment–Environment–Ph.D. Student

/graduate Team Members

  • Alex Diaz Herrera, Environmental Policy-PHD
  • Jasmine Parham, Biology - PHD
  • Paula Sarmiento, Environmental Policy-PHD
  • Payton Wood, Global Health - Cer
  • Alejandra del Campo Farro, Master of Environmental Management, Business and Environment

/undergraduate Team Members

  • Caroline Hancock, Environmental Sci/Policy (AB)
  • Chloe McGeehan
  • Njoki Mwangi, Economics (AB)
  • Abigail Walden

/yfaculty/staff Team Members

  • Emily Bernhardt, Arts & Sciences-Biology

/zcommunity Team Members

  • Andrea Carolina Encalada, Universidad San Francisco de Quito
  • Carlos Mena, Universidad San Francisco de Quito
  • Melany Ruiz-Urigen, Universidad San Francisco de Quito