South Africa's Minamata, an Analysis of the Thor Chemicals Saga 1989 – 2020

Abstract

This study analysed historical data collected over thirty years to evaluate the extent of environmental contamination and health risk associated with mercury (Hg) pollution attributed to Thor Chemicals, South Africa. Data from several sources were pooled to describe pollution trends over time. Total Hg levels directly below the plant remain extremely high and a cause for concern. Mercury levels in fish have increased significantly from 1999 to 2009 (p=0.0001) and the consumption of Catfish poses a risk to local communities with median values of 1.15 μg/g, it is very likely that Hg levels in fish have increased over the last decade as no recent data are available. In 1999 all human and animal hair samples were below 0.5 μg/g. However, by 2010 levels had increased significantly (p=0.016) among people living near the Inanda Dam (median 2.46 μg/g), as well as near the plant (median 2.62 μg/g in 2020). Immediate environmental remediation is required, and the remaining stockpile of Hg needs to be disposed of. Current fish Hg levels need to be established to develop fish consumption guidelines. A comprehensive environmental epidemiological study with a focus on pregnant women and children is needed to develop appropriate health protection interventions. Funding Statement: This research received no external funding. Declaration of Interests: The authors declare no conflict of interest.