Trans-provincial health impacts of atmospheric mercury emissions in China

Abstract

Mercury (Hg) exposure poses substantial risks to human health. Investigating a longer chain from economic activities to human health can reveal the sources and critical processes of Hg-related health risks. Thus, we develop a more comprehensive assessment method which is applied to mainland China-the largest global Hg emitter. We present a map of Hg-related health risks in China and estimate that 0.14 points of per-foetus intelligence quotient (IQ) decrements and 7,360 deaths from fatal heart attacks are related to the intake of methylmercury in 2010. This study, for the first time, reveals the significant impacts of interprovincial trade on Hg-related health risks across the whole country. For instance, interprovincial trade induced by final consumption prevents 0.39 × 10^-2 points for per-foetus IQ decrements and 194 deaths from fatal heart attacks. These findings highlight the importance of policy decisions in different stages of economic supply chains to reduce Hg-related health risks.

Fig. 1

Spatial distributions of per-foetus intelligence quotient (IQ) decrements and fatal heart attacks induced by the intake of methylmercury (MeHg) in China. a Total number induced by the intake of MeHg from all mercury (Hg) emission sources, and b the number induced by the intake of MeHg from Chinese anthropogenic Hg emissions. The coloured background represents the deaths from fatal heart attacks, and blue bars represent the points of per-foetus IQ decrements

Fig. 2

Contributions of anthropogenic sources to the national attributable per-foetus intelligence quotient (IQ) decrements (0.08 points) and fatal heart attacks (4532 deaths) in China. The attributable IQ decrements and fatal heart attacks refer to these provincial health risks caused by Chinese anthropogenic sources. a, b The results for fatal heart attacks and IQ decrements are shown as coloured bars and black solid diamonds, respectively. c The top three sectors are listed for each geographical source, and the remaining sectors are grouped as other sectors. The results for top sectors are the same for fatal heart attacks and IQ decrements. Int’l exports and Int’l imports represent international exports and international imports, respectively. The sector names are shorthand versions of the standard names (see Supplementary Table 1). Detailed results for the other sectors in c are shown in Supplementary Data 2

Fig. 3

Composition of attributable per-foetus intelligence quotient (IQ) decrements and fatal heart attacks in a given Chinese region. The composition in a given region results from anthropogenic mercury (Hg) emissions discharged by production activities (a, d), induced by final consumption (b, e), and enabled by primary inputs (c, f) of local and external regions. a–c The results for IQ decrements and d–f the results for fatal heart attacks. Each cell in the grid shows the fraction of the health risk (%) of the column region caused by the production, final consumption, and primary inputs of the row region. The total points of per-foetus IQ decrements that occur in each region are shown at the top of a, and the total deaths from fatal heart attacks that occur in each region are shown at the top of d. The total deaths from fatal heart attacks caused by each region are also shown on the right of d–f. Regions 1 to 9 represent the Northeast, Beijing-Tianjin region, North, Northwest, Central, Central Coast, South Coast, Southwest, and Int’l exports/imports (see Supplementary Fig. 3 for regional definitions). A black-coloured cell in a region reflects the fraction of health risks in the region caused by local activities. In other cells, darker orange cells indicate higher fractions

Fig. 4

Spatial relocation of atmospheric mercury (Hg) emissions and deposition as well as Hg-related intelligence quotient (IQ) decrements and fatal heart attacks over China due to interprovincial trade. The relocation is evaluated by the difference between interprovincial trade of products versus producing the same products locally under a hypothetical absence of interprovincial trade. a, c, e, g The results for the interprovincial trade of products induced by final consumption, and b, d, f, h the results for the interprovincial trade of products enabled by primary inputs. The number at the top of each panel shows the net national change with the sum of changes in all provinces