Recent heavy metal pollution from the territory of the former Soviet Union (FSU): Ice core records and emission estimates

Atmospheric heavy metal pollution from metal smelting, mining, and fossil fuel combustion poses a major threat to human health and the environment. Anthropogenic emissions from the territory of the former Soviet Union (FSU) considerably contributed to heavy metal pollution in Europe. However, due to limited monitoring and fragmentary reporting, FSU emission levels remain poorly quantified and recent trends are controversial. This study compares post-SU anthropogenic emissions of heavy metals (Ag, Bi, Cd, Cu, Pb, Sb, Zn) to those from the SU era based on new state-of-the-art emission estimates for 1975-2015 and ice-core reconstructions spanning the period 1700-2018. Ice-core records from the Tsambagarav and Belukha glaciers in the Altai region reveal marked increases in heavy metal concentrations during 1930-2018, with peak pollution levels from the FSU territory in the 1970s and 2000s, coinciding with periods of industrial growth. According to the new emission estimates, all seven heavy metals experienced a continuous 60-90 % decline in emissions between 1975 and 2015. The ice-core data confirm such a significant reduction for Cu, Sb, and Zn. However, concentrations of Ag, Bi, Cd, and Pb remained elevated in 2010-2018, at 40-70 % of their 1970s levels. These persistently high recent levels, along with the secondary concentration peaks in the early 21st century, suggest that emissions from reemerging metal production in the FSU countries after the dissolution of the SU are underestimated.