BIOMETAProject ID: 326736
Biomethylation and Biovolatilisation of Arsenic in Soils: Using Carbon and Hydrogen Isotopes to Unravel the Mechanisms and Pathways Involved
Total cost:EUR 184 709,40
EU contribution:EUR 184 709,40
Topic(s):FP7-PEOPLE-2012-IEF - Marie-Curie Action: "Intra-European fellowships for career development"
Call for proposal:FP7-PEOPLE-2012-IEFSee other projects for this call
Funding scheme:MC-IEF - Intra-European Fellowships (IEF)
Arsenic (As) is a ubiquitous element found in almost every environmental compartment. Moreover, inorganic As is a Class 1 non-threshold carcinogen and globally, millions of people are at risk, mainly through drinking tainted water which is also used to irrigate agricultural soils.
As is found in soils in its inorganic form but also as organic As, mostly mono- and dimethylarsenic (MMA(V) and DMAV(V), (III) and (V) being the different oxidation states). The process leading to these compounds, biomethylation, is biological and it is still not fully understood. Moreover, it is linked to another remarkable mechanism: biovolatilisation. Microorganisms in soil transform inorganic As to much less toxic methylated compounds, mostly MMA(V) and DMA(V), producing as well reduced methylated compounds (MMA(III) and DMA(III)) which are even more toxic than inorganic As. Biovolatilisation leads to the production of four highly volatile As compounds (arsine, mono-, di- and trimethylarsine) and their toxicity is still highly discussed.
Although the products are known, only indirect evidence exists on the different possible pathways, which are still highly debated. We propose here to employ a dual isotope approach, using 2H and 13C labeled methyl groups, placed on different methylated As molecules, to unravel As biomethylation & biovolatilisation pathways. These compounds will be injected in As methylating bacteria, fungi & protozoa cultures and in soil microcosms. The resulting molecules (including volatiles) will be measured/traced using analytical speciation techniques such as cryotrapping & GC coupled with state of the art IRMS instruments.
These experiments will shed light on processes that lead to an array of As molecules of varied toxicities and physico-chemical properties being released in soils. Indeed, such knowledge is essential in order to better assess the threat of As pollution but also in order to potentially use these processes as tools for soil remediation.
EU contribution: EUR 184 709,40
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