Deciphering past and present atmospheric metal pollution of urban environments: The role of black crusts formed on historical constructions

Abstract

Construction materials affected by black crusts (BCs) can be subjected to restoration, demolition, recycling or even to their management as waste products, thus determining their chemical features should be considered a crucial step before to undertake any action. In this work, we present the development of an analytical methodology useful to be implemented as a routine screening tool to detect recent and past atmospheric emissions of heavy metals, nowadays superficially deposited or even encapsulated in BCs. For its development, BCs together with their corresponding construction materials were sampled from the historical construction Punta Begoña Galleries (Getxo, Basque Country, North of Spain). To detect the superficial (recent depositions) and internal (past accumulations) metallic accumulations in the BCs quickly and in a cost-effective way, BCs thin sections were analysed by elemental spectroscopic imaging techniques (SEM-EDS and µ-ED-XRF). Additionally, Raman imaging studies allowed to perform the molecular speciation study of lead, the main metal accumulated inner in the BCs and coming from past atmospheric deposition events. To propose the reactivity pathway, which leads to the formation of the lead compounds, chemical equilibrium modelling was used. Finally, ICP-MS technique allowed determining the concentration of main metals accumulated in the total mass of the BCs, and through lead isotopic ratio analysis the possible source of metallic particles emission was also approached.

Stone-built heritage as a proxy archive for long-term historical air quality: A study of weathering crusts on three generations of stone sculptures on Broad Street, Oxford

“…Journal Pre-proof stratigraphies (e.g. Del Monte et al 2001b;Bonazza et al, 2007;Török et al, 2011;La Russa et al, 2018;Barca et al, 2014;Ruffolo et al, 2015;Rampazzi, 2019;García-Florentino et al, 2020).…”

“…Despite improvements in European air quality over the last 50 years, atmospheric pollution and its legacy remain one of the major threats to urban stone-built heritage (e.g. Fassina, 1978;Zappia et al 1998;Bonazza et al, 2007;García-Florentino et al, 2020). Limestone is particularly susceptible to the effects of air pollution, and easily dissolved or indurated (e.g.…”

“…Crusts occur more often and are more pronounced in polluted environments such as urban settings (e.g. Marszałek et al, 2014;García-Florentino et al, 2020). As a result, crusts contain varying mixtures of dust, airborne particles, Polyaromatic hydrocarbons (PAHs) and carbonaceous particulate matter (e.g.…”

“…Fobe et al, 1995;Farkas et al, 2018). This accumulation has been investigated as long-term repositories for air pollutants over the last two decades (Ausset et al, 1998;Del Monte et al, 2001a;Schiavon et al, 2004;Slezakova et al, 2011;Prieto-Taboada et al, 2013;Ruffolo et al, 2015;Morillas et al, 2016 and2019;Pozo-Antonio et al, 2017;La Russa et al, 2017 andRampazzi, 2019;Comite et al, 2020;García-Florentino et al, 2020). However, the majority of recent studies provide only coarse resolution reconstruction of pollution, able to distinguish between "inner=ancient/old" and "outer=modern" crust layers.…”

Sustainable Population Growth in Low-Density Areas in a New Technological Era: Prospective Thinking on How to Support Planning Policies Using Complex Spatial Models

“…Additionally, and more recently, some authors have mentioned sustainability as the new revolution that has emerged in the past few years [101]. Sustainability has been studied by the scientific community from different perspectives, such as pollution in cities [102], traffic jams [103], overcrowded cities [104], and food security [34]. In this new era of environmental concerns and technological advances, new lifestyles and new job opportunities have emerged.…”