TRACKING DEGRADATION OF SOIL POLLUTANTS WITH MULTI-ELEMENTAL COMPOUND-SPECIFIC ISOTOPE ANALYSIS – DECiSIvE

DECISIVE - Tracking degradation of soil pollutants with multi-elemental compound-specific isotope analysis

Agricultural and urban soils were exposed to many organic pollutants (pesticides, industrial pollutants) which are leached to groundwater. Transition to eco-phyto practice and clean production will stop most new contamination, but old contamination still needs to be managed, because pollutants and some degradation products leach to groundwater and drinking water, or run to surface water where they contaminate fish and the food chain. The project DECiSIvE proposes a new tool to monitor the natural degradation of organic chemicals: Multi-Element Compound-Specific Stable Isotope Analysis (ME-CSIA). With the help of this technique, the processes acting on remaining pollutants (e.g. physical processes, abiotic degradation or biodegradation) can be identified and the advancement of removal can be quantified. This technique will be used in agricultural and urban soils for the target pollutants hydrocarbons, substituted phenyl-ureas (e.g. isoproturon), s-triazines (e.g. atrazine, simazine), chloroacetanilides (e.g. S-metolachlor) and chlordecone, including stable isotopes of carbon, hydrogen, nitrogen and chlorine. The project is structured in 6 work packages: WP1) Coordination; WP 2) Database of stable isotope values for commercial formulation; WP3) Development of specific extraction/purification methods for pesticide CSIA in soils; WP4) Abiotic transformation of soil persistent pollutants; WP5) Biotic degradation of soil persistent pollutants by ME-CSIA; and WP6) : Dissemination of results. The project partners are the Laboratory of Environmental Chemistry of Aix-Marseille University, the Laboratoire d’Hydrologie et de Géochimie of Strasbourg University and the unit Agroecology of the INRA at Dijon. The fallout of this project is a validated tool and a guideline allowing the application of ME-CSIA and the decision between natural attenuation and enhanced remediation, and guiding the management practice of land in transition to sustainable eco-functioning.