Geology Department to Host Talk on Impact of Lead Poisoning due to Artisanal Gold Mining

The University of St. Thomas Department of Geology and the Environmental Science Program will host a presentation by Dr. Geoff Plumlee, senior research geochemist with the U.S. Geological Survey, on Thursday, Oct. 13.

Dr. Geoff Plumlee

Dr. Geoff Plumlee

The event, “Responding to an Outbreak of Acute Lead Poisoning Linked to Artisanal Gold Ore Processing in Nigeria: Contributions From the Earth Sciences,” will be held from 7 to 8 p.m. in 3M Auditorium, Room 150, Owens Science Hall.

Questions to be addressed are:

  • What are the effects of extracting the metals we use?
  • What are the economic, environmental and ethical consequences?
  • How are scientists responding to the problem and helping to create solutions?

Artisanal mining and ore processing carried out by individuals rather than companies is a widespread practice in numerous developing countries with the potential to directly involve millions of people worldwide. Adverse environmental and health impacts of this practice in mining gold have been well recognized, primarily due to contamination from mercury used in amalgamation extraction.

In spring 2010, a Médecines Sans Frontières (MSF) field team and local Nigerian public health officials carrying out meningitis surveillance discovered a substantially different concern, an outbreak of acute lead poisoning in northern Nigerian villages where artisanal gold ore processing is practiced. In May 2010 the U.S. CDC deployed a rapid response team to two of the hardest-hit villages to help assess the extent of the problem.

MSF and CDC quickly surmised that the poisoning was likely due to contamination from the artisanal processing of lead-rich gold ores in the villages and family compounds. The outbreak has since been determined to have affected thousands of people and resulted in the deaths of hundreds of children, most less than 5 years old.

Earth scientists from the U.S. Geological Survey are working with the CDC, MSF and other organizations to help understand sources and exposure pathways for the lead and other potential toxicants in the ores, and for mercury used in amalgamation extraction of the gold. The ores are enriched in highly bioaccessible lead carbonate and oxide minerals formed by natural weathering over the millennia prior to mining.

A primary exposure pathway is likely ingestion via hand-to-mouth contact of soils severely contaminated by dust and other byproducts from the processing. These results are being used in Nigeria to help reduce exposures to and remediate contamination from ore processing. The results also have important implications for assessing similar hazards elsewhere in the world where artisanal gold mining is mushrooming in response to the high price of gold.

For more information email Dr. Melissa Lamb, chair of the Geology Department.