Contribution of mine-derived airborne particulate matter to Ca, Fe, Mn and S content and distribution in the lichen Punctelia hypoleucites transplanted to Bajo de la Alumbrera mine, Catamarca (Argentina)

Abstract

Abstract The aim of this work is to relate the contribution of mine-derived airborne particulate matter to Ca, Fe, Mn and S content and distribution in Punctelia hypoleucites transplanted to Bajo de la Alumbrera, an important open-pit mine in Catamarca, Argentina. Lichen samples were transplanted to four monitoring sites: two sites inside the mine, and two sites outside the mine. After three months, elemental distribution in samples were analyzed by micro-Particle induced X-ray emission, and elemental concentration was determined by specific techniques: Ca and Fe by instrumental neutron activation analysis; Mn by inductively coupled plasma atomic emission spectrometry; S by a turbidimetric method. As a result, a differential distribution of S and Ca in thalli transplanted inside-mine sites was detected compared to that of samples transplanted outside-mine sites. An overlap of Fe and S in the upper cortex of the apothecium section was observed, leading to infer a mineral association of both elements. Similar association was observed for Ca and S. In addition to these results, the significantly higher concentration detected for S and Mn in inside-mine sites samples suggests a contribution of Fe, S, Ca and Mn of mining origin to the content and distribution of these elements in P. hypoleucites. Micro PIXE complemented with Mössbauer spectroscopy analysis determined the presence of pyrite particles together with other iron-bearing minerals with different degrees of oxidation were detected. These results point out to a mining origin of the airborne particulate matter trapped by the lichen thalli transplanted to Bajo de la Alumbrera.