Numerical simulator for the accumulation by crops of inorganic trace elements contaminants of soils – SIM TRACES

Soil contamination by metallic trace elements (MTE) is a major concern because many MTEs are toxic to living organisms at very low concentrations. In general, human beings are exposed to these contaminants through food consumption because MTE are taken up from soil by food and feed crops. Currently, soil contamination by MTEs has become a major issue for different reasons. First, the intensification of human activity is favorable to more frequent contamination while in parallel, societal demand for food safety is increasing. European regulations for the sanitary quality of plant products is in the process of hardening following the recent recommendations of the European Food Safety Authority (EFSA), which concluded that the dietary exposure to particular MTE such as Cd is too high. Lowering regulatory limits for MTE concentrations in crops threatens their marketability. Finally, environmental policies such as the "Grenelle Environment" encourage the recycling of agricultural waste products, which are also sources of contaminants for soils (ADEME 2007). There is a real challenge for public health and for economic and environmental issues to better asses and manage the risk of MTE accumulation by feed and food crops and to develop phytoextraction of MTEs from soil to preserve ecosystem functioning.
Therefore, the project SIM-TRACES (Numerical simulator of the accumulation by crops of trace contaminants in soil) aims at developing a generic model to simulate the transfer of MTEs from the soil to the harvested plant organ. The simulator integrates current scientific knowledge on the geochemistry of MTEs in soil and on crop physiology. It will be a tool contributing to the management and the remediation of soils contaminated by MTEs. The simulator will evaluate scenarios (interaction between soil conditions, climate and agronomic practices) and will prioritize processes to identify possible actions to minimize contamination of food and feed crops and to strengthen the use of phytoextraction.
Highlights of the project are:
- To have an integrated approach of the soil and crop functioning. The project aims to break the disciplinary boundaries found in the literature to achieve a balanced description of the different major processes governing the accumulation of MTEs by crops. For this, three sub-models dealing with the specifics of MTEs (MTE bioavailability in soil, root absorption, distribution between organs) will be interfaced with a crop model: STICS.
- To produce a generic model in order to address the current rapidly changing context. Modelling will be mechanistic and will identify the fundamental processes to describe the behavior of most MTEs.
- To analyze the models that will be developed to rank the processes so that major ones could be tested as practices to manage and the remediate soils contaminated by MTEs