Particle-Bound Mercury Characterization in the Central Italian Herbarium of the Natural History Museum of the University of Florence (Italy)

Abstract

Museums air quality can be negatively affected by treatments with heavy metals compounds employed to prevent pest infestations. Among these, the past use of mercury dichloride (HgCl2) on herbaria artifacts currently produces high levels of indoor atmospheric gaseous mercury (Hg0) and possibly of particulate bound Hg (PBM), i.e., the particulate matter containing Hg. This study evaluates the PBM pollution in the Central Italian Herbarium (Natural History Museum of the University of Florence, Italy), characterizing the size range and chemical speciation with SEM-EDS microanalysis. The analysis of the total Hg concentration in the samples allowed to calculate the workers exposure risk to this pollutant. PBM is almost totally classifiable as fine particulate with a significant dimensional increase in a period of scarce attendance of the Herbarium rooms. The microanalysis indicates that Hg is essentially bound to S, highlighting the change of Hg speciation from the original association with Cl. The average Hg concentration reveals a potential health risk for workers as result of multiple Hg exposure pathways, mainly by ingestion. The study provides information for characterizing PBM pollution that could affect a workplace atmosphere and a useful basis to evaluate and correctly design solution strategies to reduce the contamination levels and protect workers’ health.

Mercury accumulation efficiency of different biomonitors in indoor environments: the case study of the Central Italian Herbarium (Florence, Italy)

“…Notably, the measurements carried out in the Herbarium during the present study quantified only GEM; a previous study clearly indicated the presence of particulate Hg in the Herbarium (Ciani et al 2021b ). In the present study, the 24-h PM surveys carried out in the four exposition halls (Fig.…”

“…Mercury dichloride was employed from the Herbarium ’s foundation (1842) until the beginning of the last century (Passerini and Pampanini 1927 ). Recent studies proved the presence of high Hg concentrations in all the exhibition rooms, both as GEM and PBM (Cabassi et al 2020 ; Ciani et al 2021b ). The Herbarium is located on two different floors of the same building (Fig.…”

“…Here, we present the results obtained performing biomonitoring experiments in an indoor environment with particular characteristics such as a museum botanical section, i.e., a herbarium. These museum sections are often affected by serious indoor Hg pollution, due to the past use of corrosive sublimate (HgCl 2 ), employed to prevent plant infestation (Briggs et al 1983 ; Hawks et al 2004 ; Oyarzun et al 2007 ; Kataeva et al 2009 ; Fellowes et al 2011 ; Webber et al 2011 ; Havermans et al 2015 ; Fallon et al 2016 ; Marcotte et al 2017 ; Cabassi et al 2020 ; Ciani et al 2021b ). Three different biomonitors were used, tree barks, lichens, and mosses, simultaneously exposed in indoor atmosphere of the Central Italian Herbarium (Natural History Museum, University of Florence, Italy), to monitor the Hg pollution that affects this museum section.…”