Rapid minero-chemical classification of volcanic ash and inorganic dust at PM10 level: the longer-term effects of short-term hazards in the Canary Islands.

Abstract

Environmental exposomes in the natural environment include silicate ash from volcanic eruptions and wind-blown mineral dust, both of which may promote lung disease if subjected to prolonged exposure. In order to develop strategies for risk mitigation in populations subjected to hazardous minerals in the environment, it may be useful to integrate mineral chemical composition with the three-dimensional particle characteristics (e.g. shape and surface characteristics) as a means to fully assess potential mechanisms of toxicity. In this contribution we show how a combination of confocal laser microscopy, a non-destructive technique capable of resolving true 3D geometry of PM10 and PM2.5 particles, with spectroscopic analysis, provides a novel and rapid way to assess the minero-chemical properties of potentially hazardous airborne material (Wertheim et al. 2017).Initial results using samples from the 2021 La Palma volcanic eruption (volcanic silicate ash) show that volcanic particles (angular forms) increased pneumococcal adherence to A549 lung epithelial cells in vitro (Miyashita et al. 2022). Preliminary confocal images of airborne mineral dust originating in Saharan Africa and deposited on Tenerife during a sandstorm (Calima event, February 2020), show more rounded, mature particle shapes than volcanic ash, yet with clear variations in surface features. Hence we are investigating whether Calima particles could also affect pneumococcal adherence to lung cells in vitro.Applying such a multidisciplinary approach combining results from different techniques may help to raise awareness of and prevent longer-term occupational hazards in populations such as the Canary Islands, where residents are at risk of multiple sources of exposure to both volcanic ash and inorganic dust.ReferencesWertheim D, Gillmore G, Gill I, Petford N. High resolution 3D confocal microscope imaging of volcanic ash particles. Sci Total Environ. 2017 Jul 15;590-591:838-842. DOI: 10.1016/j.scitotenv.2017.02.230.Miyashita L, Coldwell B, Wertheim D, Giddens R, Gill I, Petford N, Pérez N and Grigg J. La Palma Volcanic Ash Particles Increase Susceptibility to Pneumococcal Infection In Vitro. European Respiratory Journal 2022 60: 3163; DOI: 10.1183/13993003.congress-2022.3163