Release, biomethylation, and biovolatilisation of arsenic and antimony in the environment: from soils to plants and humans

Antimony (Sb) and arsenic (As) are two toxic trace elements commonly found in soils. While As has been extensively studied, relatively little is known about Sb despite it being a toxic and potentially carcinogenic metalloid listed as a pollutant of primary concern. Both elements are redox-sensitive and their biogeochemical cycles are strongly influenced by (micro-)organisms. This leads to the formation of different chemical species of varying mobility and toxicity. To understand their environmental fate, one must therefore rely on complex extraction and speciation analysis techniques such as chromatography coupled to mass spectrometry. In the environment, these two trace elements can be released from soil due to flooding, thereby becoming available to soil (micro-) organisms and plants, the starting point of the food chain. Once released, they can undergo a number of biotransformations, two of which are of specific interest to me since my PhD: biomethylation and biovolatilisation. These two intertwined biological mechanisms are impacted by land use and climate change, but the underlying mechanisms are still not fully understood. In this talk, I will introduce these two elements as well as key concepts and drivers of release, biomethylation, and biovolatilisation. I will then focus on the release of Sb from soil to soil solution, and subsequent biovolatilisation and plant uptake. Another highlight will be set on the release and biotransformation of As under the influence of climate (flooding and temperature). Further, I will present some new research from our group on atmospheric transport of volatile As, the prevalence of methylated As species in Swiss rice paddies, and the influence of the gut microbiome on As retention, excretion, and speciation in mice.

*** invited by BayCEER members Kerstin Hockmann & Britta Planer-Friedrich

• BayCEER Colloquium Prof. Dr. Adrien Mestrot