Cadmium is a harmful element due to its toxicity and long half-life time in human bodies. It is an extremely toxic industrial and environmental pollutant classified as a human carcinogen. Cereals are indeed the major sources of cadmium for humans and, in particular, rice, a staple food in several Asian countries, is a particularly high source of this heavy metal.
To reduce cadmium concentrations in rice, the mechanisms that determine its availability from soil to plants, its plant uptake and its transport processes need to be well understood. The present study, resulting from a scientific collaboration involving young researchers among international institutions and large scale facilities between France, Switzerland, Italy, Spain and Japan (the University of Grenoble Alpes, the ETH Zurich institute, the Okayama University, the Ente italiano Nazionale Risi and the ALBA and Soleil synchrotrons), aims to enlighten these mechanisms.
Cadmium usually binds to sulfur, getting immobilized, and the bindings with sulfur is the major driving force for cadmium isotope fractionation (when the isotopic composition of an element of a given compound changes by the transition of that compound from one physical state or chemical composition to another).
The results of this research show how soil flooding in the rice crops not only changed the cadmium speciation in the solid soils but also in soil-aqueous solutions, while vacuolar transport includes the dissociation of heavy cadmium isotopes from a sulfur donor atoms prior to membrane transport and storage in the vacuole. All these findings allow a better tracing of contaminant elements in the complex soil-plant system and permit to asset about final product toxicity when those plants are source of human food.
Read more on the ALBA website
Image: rice crops