Antimony as a tracer of non-exhaust traffic emissions in air pollution in Granada (S Spain) using lichen bioindicators

Dr. A. Parviainen acknowledges the ‘Juan de la Cierva —Incorporación’ (IJCI-2016-27412) Fellowship funded by the Spanish Ministry of Economy, Industry, and Competitiveness (MEIC). C.J. Garrido received funding from the “Junta de Andalucía” research grant RNM-131. Fellowships, research and infrastructure grants supporting this research have been (co)funded by the European Regional Development Fund (ERFD) and the European Social Fund (ESF) of the European Commission.

We have studied the metal air pollution trends in a medium-sized Spanish city suffering from traffic emission using in-situ lichen Xanthoria parietina as a bioindicator. The large scale sampling included 97 samples from urban, metropolitan and remote control areas of Granada that were analyzed by Inductively Coupled Plasma-Mass Spectrometry. Enrichment factor of Sb exhibited severe anthropogenic enrichment, whereas Cu and Sb showed significantly higher median values in the urban areas with respect to metropolitan areas. Additionally, bioaccumulation ratios of V, Cr, Ni, Cu, Zn, Cd, Sb, and Pb —associated to exhaust and non-exhaust traffic emissions— enabled us to delineate hot spots of metal(loid) accumulation in the main accesses to the city, characterized by dense traffic and copious traffic jams. To distinguish non-exhaust emissions, we studied the spatial distribution of the Cu:Sb ratio —a tracer of brake wear— highlighting the surroundings of the highway and the main traffic accesses to the city likely due to sudden hard braking and acceleration during frequent traffic jams. Our study shows that the metal(loid) contents in lichens are excellent proxies for non-exhaust traffic emissions and that their contribution to the metal(loid) air pollution in Granada is more significant than previously thought

Spanish Ministry of Economy, Industry, and Competitiveness (IJCI-2016-27412)

Junta de Andalucía RNM-131

European Regional Development Fund (ERFD)

European Social Fund (ESF)