Particle pollution and the role of ecological indicators for the preventive conservation of cultural heritage

MARCOS A. E. CHAPARRO; DEBORA C. MARIÉ; DANIELA BUITRAGO POSADA; ALDO WINKLER; MARCOS TASCON; LISA GRIFONI; MARTINA SCOCCIMARRO; FEDERICO CHERNY; FERNANDO MARTE; L. PENSABENE BUEMI; FRANCESCA BOLDRIGHINI; A. RUSSO; GABRIELA STRANO; LUIGI A. DI LELLA; LILLA SPAGNUOLO; STEFANO LOPPI; ANTONIO SGAMELLOTTI

Malargüe

Encuentro; 18° Encuentro Internacional de Ciencias de la Tierra, E-ICES 18; 2023

ICES

Anthropogenic particle pollution is an increasing concern in urban contexts because it may adversely influence citizens' cultural heritage (CH), such as museums, archaeological sites, and historic buildings. Among adverse consequences of particulate matter (PM) on CH institutions, it may act on the surfaces, creating dark layers, abrasion of materials, depletion, discoloration, and consequent artistic loss. The latter has recently been studied using magnetic biomonitoring in various Italian institutions and urban archaeological sites, including Villa Farnesina in Rome, the Peggy Guggenheim Collection in Venice, and the Palatino Hill of Parco Archeologico del Colosseo. We present here the first magnetic biomonitoring study in Argentina focused on the preventive conservation of the collections preserved at the Museo Nacional de Bellas Artes (MNBA) and the Museo Histórico Nacional (MHN) in Buenos Aires. Thalli of lichen species (Parmotrema pilosum) were collected at remote sites and transplanted to indoor and outdoor sites for three months. In addition, for biomonitoring purposes, leaves from urban trees (Jacaranda mimosifolia and Fraxinus excelsior) were collected at increasing distances from MNBA and MHN, respectively. The magnetic properties of lichens and leaves were determined in situ and at the laboratory through the following measurements: magnetic susceptibility, anhysteretic, and isothermal remanent magnetization. Lichen transplants evidenced lower magnetic concentration and finer grain size of trapped airborne magnetic particles (AMP) for indoor (AMP content = 20-140 μg) than outdoor (AMP content = 160-590 μg) sites, where magnetite-like minerals dominate (remanent coercivity Hcr = 34.3-37.7 mT). Higher values of mass-specific magnetic susceptibility χ were obtained for tree leaves of J. mimosifolia (χ = 13.1-50.4 ×10-8m3kg-1) than F. excelsior (χ = 0.6-7.5 ×10-8m3kg-1). Further magnetic analyses are ongoing on Evernia prunastri lichen transplants. Moreover, elemental analysis of lichens and leaves will be conducted by ICP-MS to expand the information regarding the origin and impact of the pollution.