Arsenic and SO2 hotspot in South-Eastern Europe: An overview of the air quality after the implementation of the flash smelting technology for copper production.

This extensive study considered the air pollution data after the flash smelting technology for copper production had become fully operational. The assessment of the air quality after the implementation was significantly important, since the modernisation was necessary for reducing the environmental contamination in one of the most polluted regions in South-Eastern Europe. The concentrations of SO2, PM10 and toxic elements (As, Pb, Cd, Ni) in PM10 samples were monitored at different sites, with respect to the copper smelter, in the period 2016-2019. The air quality evaluation was performed concerning the corresponding limit and target values defined by the Serbian and European legislation, as well as the World Health Organization Air Quality Guidelines (WHO AQG). The measured SO2 concentrations indicated frequent exceedances of the defined daily and annual limit values, at both national and European level. Although exceedances were not as pronounced as in the period before the implementation of the new technology, the episodes of extreme air pollution with SO2 persisted on the daily basis. The maximum daily SO2 concentration of 2125 μg m-3 was more than 100 times higher compared to the WHO AQG, but lower compared to the period before the implementation of the flash smelting technology. The air quality considering PM10 and especially As levels in PM10 samples was notably poorer after the modernisation. The annual target value for As, defined by the European and Serbian Regulation, was exceeded at all the measuring sites, with maximum exceedance of more than 90 times at the suburban site during 2019. The frequent exceedances of the corresponding annual limit and target values were also denoted for Pb and Cd in PM10 samples. The analysed data emphasised that the Bor area could still be characterised as an environmental hotspot in Serbia and beyond.