Arsenic speciation study of PM 2.5 in an urban area near a copper smelter

Abstract

An arsenic speciation study has been performed in selected PM 2.5 samples collected at an urban background monitoring station of the city of Huelva during 2001 and 2002, which registers the emission derived from a nearby copper smelter. The mean total As concentration of the PM 2.5 samples analyzed during 2001 (6.4 ng m −3) and 2002 (7.9 ng m −3) slightly exceed the mean annual 6 ng m −3 target value proposed for PM 10 by the European Commission for 2013. The speciation analysis shows that arsenate [As(V)] is the main arsenic species found, followed by arsenite [As(III)] (mean 5.8 and 1.2 ng m −3 for As(V) and As(III), in PM 2.5, respectively, during 2001–2002). Three atmospheric and emission scenarios have been distinguished from a cluster analysis using trace elements (Pb, Zn, Cu and Se) and As species derived from the copper smelter: (a) Anthropogenic, (b) Anthropogenic plus African dust outbreak and (c) Atlantic advection. Highest As total mean concentration was found during the anthropogenic episodes (23.3 ng m −3), followed by the anthropogenic plus African dust outbreak episodes (9.2 ng m −3) and Atlantic advection days (2.2 ng m −3). These scenarios have been identified in a previous work on the As species analysis in PM 10. During Atlantic advection days, the As(III)/As(V) ratio in PM 2.5 and PM 10 was high, whereas low As(III)/As(V) ratio in both PM 2.5 and PM 10 samples has been displayed during the anthropogenic scenarios. The As(III)/As(V) may be considered as a fingerprint of the origin of the particulate matter.