PhD position OT-28897
Fate of PFAS in agricultural soils
11100 NARBONNE - 84000 AVIGNON - 95000 CERGY
INRAE presentation
The French National Research Institute for Agriculture, Food, and Environment (INRAE) is a major player in research and innovation. It is a community of 12,000 people with 272 research, experimental research, and support units located in 18 regional centres throughout France. Internationally, INRAE is among the top research organisations in the agricultural and food sciences, plant and animal sciences, as well as in ecology and environmental science. It is the world’s leading research organisation specialising in agriculture, food and the environment. INRAE’s goal is to be a key player in the transitions necessary to address major global challenges. Faced with a growing world population, climate change, resource scarcity, and declining biodiversity, the Institute has a major role to play in building solutions and supporting the necessary acceleration of agricultural, food and environmental transitions.
Work environment, missions and activities
Host company: Veolia Agriculture
Host laboratories: at INRAE :
- Laboratoire de Biotechnologie de l'Environnement (LBE), 11100 Narbonne
- Environnement Méditerranéen et Modélisation des Agro-Hydrosystèmes, (EMMAH), 84000 Avignon.
Context
Per- and polyfluoroalkyl substances (PFAS) are xenobiotics that have been used for several decades in a wide range of applications. Some are persistent in the environment and/or harmful to the health of living organisms. PFAS enter agroecosystems through certain pesticides, atmospheric deposition, irrigation with contaminated water, and the recycling of organic waste products (OWP). In soils, PFAS can be taken up by crops or soil organisms, migrate into groundwater, and thus pose a threat to water resources, crops, and consumer health. This thesis is part of the ANR-funded FluorAgro project (2026-2030) aimed at identifying sources of PFAS in agroecosystems, predicting their fate in soil, and studying their bioavailability. The thesis will contribute to improving predictions of PFAS fate in soil.
Objective
Study and model the fate of PFAS in the Organic-Waste–Soil–Water continuum. This objective is broken down into three research questions, which will be addressed using appropriate tools and methods:
● Do organic waste treatment processes (e.g., anaerobic digestion, composting) affect the distribution of PFAS across different organic fractions? Do they lead to the degradation of perfluoroalkyl acid precursors? What will be the consequences for PFAS mobility in soils after application?
→ Sampling of organic waste products from long-term field trials, physical and biochemical fractionation of organic matter, quantification of PFAS in each fraction
● Two mechanisms that have received little attention may control the fate of PFAS in soil: preferential transport in macropores and transport in the colloidal phase, which facilitates the mobility of pollutants that would otherwise be poorly mobile. Will the introduction of colloidal organic matter via the OWP exacerbate this transport mechanism for long-chain PFAS? Will diffusion from the soil matrix to preferential flow paths be the process that limits the leaching of shorter-chain PFAS?
→ Leaching experiments on soil column extracted from long-term field trials. Measurement of drainage hydrographs and water tracer elution curves. Quantification of the fraction of colloid-bound PFAS in the leachates, colloid characterization.
●To predict the fate of PFAS in soil, a numerical model will be developed during the FluorAgro project. The PhD student will parametrize this model from the column experiments and will test it by comparing its predictions with PFAS concentration measured in lysimeters located in the long-term field trials.
→ The modeling work will be carried out in the Vsoil platform developed by INRAE at EMMAH Avignon.
36-months fixed term contract, starting ideally in September or October 2026. The candidate will spend 9 months at LBE, 20 months at EMMAH and 7 months at Veolia.
Training and skills
The candidates must hold a Master degree or an engineer diploma and have skills in soil physics or in modeling, ideally in the field of mass transfer (water, solutes, colloidal particles) in porous media.
Previous experience with contaminant fate in soils would be a plus. An interest for experimental laboratory work is necessary
INRAE's life quality
By joining our teams, you benefit from (depending on the type of contract and its duration):
- up to 30 days of annual leave + 15 days "Reduction of Working Time" (for a full time);
- parenting support: CESU childcare, leisure services;
- skills development systems: training, career advise;
- social support: advice and listening, social assistance and loans;
- holiday and leisure services: holiday vouchers, accommodation at preferential rates;
- sports and cultural activities;
- collective catering.
How to apply
To apply, visit the ADUM web site (https://adum.fr/as/ed/voirproposition.pl?matricule_prop=72589&site=adumR) and follow the application guidelines.
Please email Eric Michel (eric.michel@inrae.fr) et Claire Lhoutellier (claire.lhoutellier@veolia.com) if you need further information regarding this proposal.
All persons employed by or hosted at INRAE, a public research establishment, are subject to the Civil Service Code, particularly with regard to the obligation of neutrality and respect for the principle of secularism. In carrying out their functions, whether or not they are in contact with the public, they must not express their religious, philosophical or political convictions through their behaviour or by what they wear. > Find out more: fonction publique.gouv.fr website (in French)