International trade shapes global mercury–related health impacts

Mercury (Hg) is a strong neurotoxin with substantial dangers to human health. Hg undergoes active global cycles, and the emission 
sources there of can also be geographically relocated through economic trade. Through investigation of a longer chain of the global 
biogeochemical Hg cycle from economic production to human health, international cooperation on Hg control strategies in Minamata 
Convention can be facilitated. In the present study, four global models are combined to investigate the effect of international trade on 
the relocation of Hg emissions, pollution, exposure, and related human health impacts across the world. The results show that 47% of 
global Hg emissions are related to commodities consumed outside of the countries where the emissions are produced, which has 
largely influenced the environmental Hg levels and human exposure thereto across the world. Consequently, international trade is 
found to enable the whole world to avoid 5.7 × 10⁵ points for intelligence quotient (IQ) decline and 1,197 deaths from fatal heart 
attacks, saving a total of $12.5 billion (2020 USD) in economic loss. Regionally, international trade exacerbates Hg challenges in less 
developed countries, while resulting in an alleviation in developed countries. The change in economic loss therefore varies from the 
United States (−$4.0 billion) and Japan (−$2.4 billion) to China (+$2.7 billion). The present results reveal that international trade is a 
critical factor but might be largely overlooked in global Hg pollution mitigation.