Transfert en cadmium et zinc vers l'orge de printemps en sols contaminés et non contaminés de Belgique: Évaluation et prédiction

Abstract

In the Walloon region (Belgium), agricultural soils close to a former ore smelter were affected by atmospheric deposition contaminated by cadmium (Cd), lead (Pb), and zinc (Zn). To study the effect of these contaminations on the quality of agricultural productions, a study of the transfer from soil to a cereal crop, barley (Hordeum vulgare L.) was carried out on one of these contaminated areas and an uncontaminated control area. Eighteen barley samples were taken in contaminated areas; 10 were sampled in the control area, and each was subdivided into three subsamples (stem, ear, and seed). A sample was taken from topsoil horizon (0 to 20 cm) at the location of each plant sample. Available and pseudo-total concentrations of trace and major elements as well as pHwater, pHKCl, total organic carbon, and total nitrogen were measured on the soil samples. Concentrations of Cd and Zn were measured in the seed, ear, and stem. The concentrations of Cd and Zn that were measured in the harvested plants in the contaminated zone are 2 to 9 times higher than those measured in the control barleys. There are few relationships between Cd concentration in seeds (CdSeed), Zn concentration in seeds (ZnSeed), and soil properties apart from available and pseudo-total soil levels of Cd and Zn. Using a Cate-Nelson analysis, CdSeed was estimated at 0.027 mg Cd/kg of dry matter (DM) for pseudo-total soil Cd levels ranging from 0 to 1.23 mg/kg, and at 0.118 mg Cd/kg DM for pseudo-total soil Cd levels ranging from 1.24 to 6.87 mg/kg. ZnSeed is estimated to be 19.2 mg/kg of DM for soil ranges from 0 to 131 mg/kg of pseudo-total Zn, and 40 mg/kg of DM for soil ranges from 132 to 570 mg/kg of pseudo-total Zn. However, an estimate of the transfer of Cd and Zn remains complex in these multi-contaminated soils.