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2009–2017 trends of PM10 in the legendary Riotinto mining district of SW Spain

Abstract:

This study is the first to perform a chemical characterization and source contribution of particulate matter (PM10) occurring through the abandonment and reopening of a historical sulphide mine. This long-range analysis covers the period 2009–2017 in the Riotinto mining district (Iberian Pyrite Belt, Southwestern Spain), which is a mining district of world-class importance. This mine represents a susceptible anthropogenic emission source of toxic sulphide-associated elements in atmospheric particulate matter, which affects the air quality of the nearby areas. A total of 567 samples of 24 h were collected from 2009 to 2017 in a rural station. The filters were analysed to determine Organic and elemental carbon, mayor and trace elements, and water soluble compounds of PM10. The trends of PM10 and geochemical characterization were studied considering the following periods: mine abandonment (2009–2014) and the mine's state during (2015–2016) and after (2017) implementation of new emission abatement technology at this mine. The results revealed relatively high concentrations of Cu, Zn, Pb, As, Sb, and Bi during 2015–2016. A reduction of 42–59% was observed after 2017 for the same elements in PM10. Five sources were identified: regional, mining, aged sea salt, combustion + traffic and crustal, using positive matrix factorization model (PMF5). The contribution of the mining factor was higher in the reopening period (4.2 μg m−3, 16%). These results have been confirmed by As speciation analysis, in which the low extraction percentage obtained is related to the origin of the metalloids associated with sulphide ores. The reduction of emissions of atmospheric particulate matter in the mining processes is the main objective in the implementation of measures considering the technological progress for cleaner and sustainable mining. In the case of reopening of historical mines, with low ore grade and greater extraction of ore and rock, a major effort must be made in order to avoid a negative influence on the environment and human health.