title: The cauliflower-like black crusts on sandstones: A natural passive sampler to evaluate the surrounding environmental pollution.
abstract: Black crust in buildings can be formed as a result of different kind of chemical and physical reactions between the stone surface and environmental factors (e.g. acid aerosols emitted to the atmosphere, airborne particulate matter, etc.). Moreover, biological colonizations can also be present on them. This kind of pathology is widely present in limestones, but fewer are the case study dealing with the characterization of black crusts on sandstones. In this work we present an innovative methodology based on the use of cauliflower-like black crusts formed on sandstone material as natural passive sampler to evaluate the environmental pollution related with the emission of natural (crustal particles and marine aerosol particles) and metallic elements in the airborne particulate matter from the surrounding atmosphere. To illustrate its usefulness, different cauliflower-like black crusts growing in areas protected from the rain growing in an historical construction, La Galea Fortress, made up of sandstone and placed in the Abra Bay (Getxo, Basque Country, Spain) were characterized. This area suffers the anthropogenic emissions coming from the surrounding industry, traffic, sea port, and the natural ones coming from the surrounding marine atmosphere. The applied analytical methodology began with a previous elemental in situ screening in order to evaluate and compare the presence of the metals trapped in black crusts from different orientations using a hand-held energy dispersive X-Ray Fluorescence spectrometer. After this preliminary study, samples of black crusts were taken in order to characterize them in the laboratory using molecular techniques (Raman spectroscopy and XRD) and elemental techniques (ICP-MS, SEM-EDS and micro energy dispersive X-Ray Fluorescence). With the last two elemental techniques, imaging analyses were performed at different lateral resolutions in order to observe the distribution of the metals and other kind of particles trapped in the black crust samples. Additionally, a biological colonization found beneath the black crusts was also characterized using Phase Contrast microscopy.
authors.affiliation: Department of Analytical Chemistry, Faculty of Science and Technology, University of the Basque Country UPV/EHU, P.O. Box 644, 48080 Bilbao, Basque Country, Spain. Electronic address: hector.morillas@ehu.es.
authors.forename: Héctor
authors.initials: H
authors.lastname: Morillas
authors.affiliation: Department of Analytical Chemistry, Faculty of Pharmacy, University of the Basque Country UPV/EHU, P.O. Box 450, 01080 Vitoria-Gasteiz, Basque Country, Spain.
authors.forename: Maite
authors.initials: M
authors.lastname: Maguregui
authors.affiliation: Department of Analytical Chemistry, Faculty of Science and Technology, University of the Basque Country UPV/EHU, P.O. Box 644, 48080 Bilbao, Basque Country, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: García-Florentino
authors.affiliation: Department of Analytical Chemistry, Faculty of Science and Technology, University of the Basque Country UPV/EHU, P.O. Box 644, 48080 Bilbao, Basque Country, Spain.
authors.forename: Jose Antonio
authors.initials: JA
authors.lastname: Carrero
authors.affiliation: Department of Plant Biology & Ecology, Faculty of Science and Technology, University of the Basque Country UPV/EHU, P.O. Box 644, 48080 Bilbao, Basque Country, Spain.
authors.forename: Isabel
authors.initials: I
authors.lastname: Salcedo
authors.affiliation: Department of Analytical Chemistry, Faculty of Science and Technology, University of the Basque Country UPV/EHU, P.O. Box 644, 48080 Bilbao, Basque Country, Spain.
authors.forename: Juan Manuel
authors.initials: JM
authors.lastname: Madariaga
mesh_terms: D003252:Construction Materials / Q000032:analysis* / Q000382:microbiology*; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods*; D004785:Environmental Pollutants / Q000032:analysis* / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D008858:Microscopy, Phase-Contrast; D013030:Spain; D013050:Spectrometry, Fluorescence; D013054:Spectrophotometry, Atomic; D013059:Spectrum Analysis, Raman; D013499:Surface Properties
chemical_list: D004785:Environmental Pollutants
keywords: Cauliflower-like black crust; HH-ED-XRF; ICP-MS; SEM-EDS; Sandstone; µ-ED-XRF imaging