Spatial-temporal changes of land-use mercury emissions in China

Land use change is closely related to human activities, and has significant impacts on pollutant emissions. Mercury (Hg) is the most toxic heavy metal element gas damaging the environment severely, and China has the largest mercury emissions. Yet, there is inadequate research which has measured mercury emissions caused by land use change in China. To assess mercury emissions systematically, we establish the spatial-temporal series of land-use mercury emission inventories of China considering indicators of both natural and anthropogenic emissions by analyzing the effects of land-use type conversion and land-use intensities. The results show that the natural land-use mercury emissions in China had a growth rate of 1.35% from 2000 to 2015. Regions with a large increase of natural land-use mercury emissions were those with large built-up land expansion. The embodied anthropogenic mercury emissions in China calculated by multi-regional input-output model had an average increasing rate of 16.53% from 2007 to 2015. Further, mining and industry land and residential land accounted for about 73.1% of the embodied mercury emissions. Jiangsu and Shandong had both a large increase in natural and anthropogenic mercury emissions, while Xinjiang and Gansu had a large increase in natural emissions but rather small embodied emissions from built-up land. The research can inform mercury pollution mitigation policies through land use management.