BIOMETA Biomethylation and Biovolatilisation of Arsenic in Soils: Using Carbon and Hydrogen Isotopes to Unravel the Mechanisms and Pathways Involved

Country: EU Projects
Start Date:   1/6/2013         Duration: 24 months         Project Type: RTD
Contract Number: 
Organisation Type:  EC Project
Contaminated land-->Soil and groundwater processes-->Microbiology
Project objectives:
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.
Project Summary:
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.
Achieved Objectives:

Product Descriptions:
Final Report summary: BIOMETA (Biomethylation and Biovolatilisation of Arsenic in Soils: Using Carbon and Hydrogen Isotopes to Unravel the Mechanisms and 
Pathways Involved) at ...
Additional Information:
Project Resources:
Funding Programme(s): 
EC FP7: Seventh Framework Programme for Research and Technological Development.
Link to Organisations:
Submitted by: EUGRIS Team Professor Paul Bardos  Who does what?  28/11/2017 13:55:00