Assessing the biological reactivity of organic compounds on volcanic ash: implications for human health hazard

Ines Tomašek,Manolis N Romanias,David E Damby,Marc Elskens,Daniele Andronico,Philippe Claeys,Claire J Horwell,Imke Boonen,Ulrich Kueppers,Matthieu Kervyn,Michael S Denison,Peter J Baxter

doi:10.1007/s00445-021-01453-4

Abstract

Exposure to volcanic ash is a long-standing health concern for people living near active volcanoes and in distal urban areas. During transport and deposition, ash is subjected to various physicochemical processes that may change its surface composition and, consequently, bioreactivity. One such process is the interaction with anthropogenic pollutants; however, the potential for adsorbed, deleterious organic compounds to directly impact human health is unknown. We use an in vitro bioanalytical approach to screen for the presence of organic compounds of toxicological concern on ash surfaces and assess their biological potency. These compounds include polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dlPCBs). Analysis of ash collected in or near urbanised areas at five active volcanoes across the world (Etna, Italy; Fuego, Guatemala; Kelud, Indonesia; Sakurajima, Japan; Tungurahua, Ecuador) using the bioassay inferred the presence of such compounds on all samples. A relatively low response to PCDD/Fs and the absence of a dlPCBs response in the bioassay suggest that the measured activity is dominated by PAHs and PAH-like compounds. This study is the first to demonstrate a biological potency of organic pollutants associated with volcanic ash particles. According to our estimations, they are present in quantities below recommended exposure limits and likely pose a low direct concern for human health.

Highlights

Volcanic ash is a product of explosive volcanic eruptions and lava dome collapses and poses a threat to human health, infrastructure, air traffic and agriculture (Wilson et al 2012, Editorial responsibility: C.E.Gregg2015)
Low levels of aryl hydrocarbon receptor (AhR) activation were detected in the polychlorinated dibenzop-dioxins and dibenzofurans (PCDD/Fs) fraction of the cleaned-up sample extracts (Fig. 3), with response levels ranging between 0.2 and 0.6 pg TCDD bioanalytical equivalent (BEQ)/g (Table 4)
The low level of AhR activity in the cleanedup PCDD/Fs fraction (< 0.6 pg TCDD BEQ/g) and lack of activity in the dioxin-like polychlorinated biphenyls (dlPCBs) fraction indicates that the chemicals in these fractions contribute little to the overall AhR activity of the total extract, where response levels were up to 122 ng BaP BEQ/g

Summary

Introduction

Volcanic ash is a product of explosive volcanic eruptions and lava dome collapses and poses a threat to human health, infrastructure, air traffic and agriculture (Wilson et al 2012, Editorial responsibility: C.E.Gregg2015). With many volcanoes situated near large cities (Heiken 2013), ash frequently interacts with the atmosphere and associated anthropogenic pollution before being inhaled. Populations are commonly exposed to volcanic ash concomitantly with additional substances, notably urban air pollutants such as vehicle and industry emissions, which are composed of a mixture of particulate matter and gaseous/volatile species. Limited understanding exists regarding the human health hazards associated with the combined exposures to volcanic particulate matter and the polluted urban environment (Tomašek et al 2016, 2018). Of particular importance is how volcanic ash interacts with urban pollutants and if this association may influence its biological reactivity and, in this way, contribute to an increase in adverse health effects for exposed populations

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