Source Apportionment of Atmospheric Deposition Species in an Agricultural Brazilian Region Using Positive Matrix Factorization

We investigated the influence of natural and anthropogenic sources on bulk atmospheric deposition chemistry, from November 2017 until October 2019, in a Brazilian agricultural area. The pH mean value was 5.99 (5.52–8.46) and most deposition samples (~98%) were alkaline (pH > 5.60). We identified Ca2+ as the predominant species, accounting for 33% of the total ionic species distribution and the main precursor of atmospheric acidity neutralization (Neutralization Factor = 6.63). PMF analysis resulted in four factors, which demonstrated the influence of anthropogenic and natural sources, such as fertilizer application and production, marine intrusion/biomass burning, and biogenic emissions, and revealed the importance of atmospheric neutralization processes.

Comparison of the trace element content in transplants of the lichen Evernia prunastri and in bulk atmospheric deposition: a case study from a low polluted environment (C Italy)

This study investigated whether lichen samples transplanted and retrieved monthly for six months reflect bulk deposition under conditions of relatively low air pollution. The study investigated also whether samples exposed for six months provide data consistent with the one-month transplants. The lichen Evernia prunastri was collected from a remote site and exposed at a study site (the Botanical Garden of the University of Siena, Italy), along with an atmospheric bulk deposition collector. Lichens and bulk deposition were analysed by ICP-MS for the content of Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sb, Ti and Zn. The results showed significant correlations between lichen content and bulk deposition for Al, As, Cu, Fe, Hg, Sb and Ti, suggesting that in one month the equilibrium is reached for these elements between the lichen and the atmosphere. The above elements (but Sb) in lichen and bulk deposition are related to soil-particulates, while traffic is the source for Sb deposition. In addition, samples exposed for 6 months showed results consistent with the one-month transplants for As, Cu and Hg, suggesting that for these elements in the study site the equilibrium is maintained also for longer periods.