Spatial Analysis of Soil Lead Exposures from Lead Poisoning Tragedy in Nigerian Mining Villages

Spatial Analysis of Soil Lead Exposures from Lead Poisoning Tragedy in Nigerian Mining Villages

By: Madi Thurston    Email:

Home Town: Kuna, ID    High School: Kuna High School

Major: Env Sc-Physical Science Opt
Department: Environmental Science
College: College of Natural Resources

Poster presented at the 2020 virtual Idaho Undergraduate Research Conference


In 2010, an unprecedented lead poisoning in Zamfara State, Nigeria resulted in the death of more than 400 children. The outbreak was caused by artisanal processing of lead-rich gold ores inside rural village homes, where incidental ingestion of contaminated soils and dusts resulted in geomean blood lead levels (BLLs) of 149 µg/dL and maximum BLLs of 600 µg/dl. Soil lead concentrations in villages averaged 300-4,143 mg/kg with a maximum of 35,380 mg/kg, regularly exceeding the United States Environmental Protection Agency safe soil lead level of 400 mg/kg. To address the environmental health emergency, the Nigerian government partnered with international organizations, including TerraGraphics International Foundation (TIFO) and Doctors Without Borders (Médecins Sans Frontières, MSF) to remediate residential areas and deliver life-saving medical treatment for poisoned children. Archived in situ field-portable x-ray fluorescent spectrometer (FP-XRF) data from the environmental response provides a unique opportunity to develop a better understanding of heavy metal exposures that can be applied to other artisanal mining and indigenous communities.

To assess spatial variability in FP-XRF soil lead concentrations, an attribute database for residential compound soil lead levels was built in ArcGIS™ for three time periods: pre-remediation, post-remediation, and remediation follow-up assessments. Household, neighborhood, and community means were calculated for each compound. Neighborhood concentrations consist of a mean of all compound and public area locations within a radius of each home. The appropriate radius value (e.g., 200’, 300’, 400’) should reflect a child’s independent mobility and is likely influenced by several factors, including age and gender. This study demonstrates that neighborhood size, contamination variability, and compound location within the neighborhood have a significant impact on a child’s exposure to contaminated soil. Future work will investigate the relative contributions of home, neighborhood, and community exposures by comparing observed versus predicted BLLs using the Integrated Exposure Uptake Biokinetic (IEUBK) model.

About Madi Thurston

Madison Thurston is majoring in environmental science with an emphasis in mathematics and statistics and geospatial tools, along with a minor in Spanish. During her time at UI, she has been awarded a national Udall Scholarship Honorable Mention and an international DAAD RISE Scholarship, among numerous Student Achievement Awards. As a member of the Doris Duke Conservation Scholars program, Madi conducted an independent research project and presented at local, regional, and national conferences, including the 2019 Ecological Society of America meeting. During the school year, Madi works as the Lead Student Coordinator for the Alternative Service Break (ASB) program that connects students with social justice-oriented volunteer projects. She also serves as a student leader for ASB and has led five trips to a variety of locations, including Idaho and Togo in West Africa. During her work in Togo, she was inspired by the work of local non-profits and found her passion to pursue the environmental justice field, which led her to TerraGraphics International Foundation (TIFO). In April 2020, Madi received a Summer Undergraduate Research Fellowship from UI to work with TIFO on a geospatial analysis of data from the 2010 lead poisoning tragedy in Zamfara, Nigeria.


Products Produced:

Type: Title: Date Published/Presented: DOI:
Poster Spatial Analysis of Soil Lead Exposures from Lead Poisoning Tragedy in Artisanal and Small-Scale Gold Mining Villages of Zamfara, Nigeria July 24, 2020

Additional Project Information:

Year in College Project Started:  Senior

Faculty Advisor:   Magrit  von Braun

Faculty Advisor Email:

Faculty Advisor Website:  

Funding Source:  Office of Undergraduate Research (SURF)

External Link to Project Information:

Project Location:   Remote