Examining the inconsistency of mercury flow in post-Minamata Convention global trade concerning artisanal and small-scale gold mining activity

In 2017, the Minamata Convention (MC) on mercury (Hg) control entered into force. However, whether the MC is effective and how it reshapes the global Hg flow remain unclear. In this study, we established a method to detect inconsistencies in data on global Hg trade, and calculated the gap between the demand and supply of Hg to the artisanal and small-scale gold mining (ASGM) sector (i.e., the largest source of Hg emissions globally) in 39 countries across four regions. According to our results, inconsistencies in statistical data concerning Hg for ASGM activities exist in both Africa and Central and South America. Asia showed a considerably lower amount of Hg applied to ASGM than apparent Hg consumption; nevertheless, the largest consumer of Hg was Asia, predomi-nantly China and India. Many countries in which ASGM is conducted are already MC parties; however, only few submitted their national action plans (NAPs) or have established/enforced specific laws to curb Hg use in ASGM. Analysis of Hg-related trade information suggests that in 2017, the trade of metallic Hg disappeared in some African and Central and South American countries, but new trade flows of goods with higher Hg content emerged. The method established in this study can support the search for countries implementing ASGM with hidden Hg use and flows, thereby contributing to the planning of further Hg control regulations. To enforce sound Hg management, the submission of NAPs should also be promoted in addition to the expansion of MC parties.

Automated summary

This study established a method to detect inconsistencies in global mercury trade data and calculated the gap between mercury demand and supply in the artisanal and small-scale gold mining sector across 39 countries. Inconsistencies in statistical data on mercury use in gold mining were found in Africa and Central and South America. Despite low mercury use in the Asian gold mining sector, Asia remained the largest consumer of mercury, primarily China and India. Many countries involved in gold mining have joined the Minamata Convention, but few have submitted national action plans or implemented specific laws to curb mercury use. The method developed in this study can help identify hidden mercury use and flows in gold mining, contributing to the development of further mercury control regulations. Promoting the submission of national action plans is essential for effective mercury management in addition to expanding the Minamata Convention parties.