Bioavailability and transfer of elevated Sm concentration to alfalfa in spiked soils

• Published in: Environmental science and pollution research international 2020-12, Vol.27 (35), p.44333-44341
• Main Authors: Hu, Ruoyu, Beguiristain, Thierry, De Junet, Alexis, Leyval, Corinne
• Format: Article
• Language: English
• Subjects: Acidic soils; Aging; Aging (natural); Alfalfa; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Bioavailability; Continental interfaces, environment; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Engineering; Environmental Health; Environmental science; Environmental Sciences; Extractants; Growth chambers; Industrial pollution; Medicago sativa; Rare earth elements; Research Article; Samarium; Sciences of the Universe; Shoots; Soil chemistry; Soil contamination; Soil pH; Soil pollution; Soils; Toxicity; Transfer factor; Waste Water Technology; Water Management; Water Pollution Control
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-020-09223-z

Rare earth elements (REEs) have been widely used in recent decades, and their exploitation has led to industrial REE emission and to contaminated soils especially in former mining areas. This raised people concerns on the accumulation and toxicity of REEs in soils and plants, and consequences on plant health. Although many studies dealt with REE in soils and plants, there is still a need to precise their toxicity, bioavailability and transfer to plants in contaminated sites in order to restore such ecosystems. We studied the bioavailability and transfer of a REE to Medicago sativa grown on two contaminated soils differing in their chemical characteristics. A pot experiment was set up in a growth chamber where two natural soils were spiked or not with samarium (Sm) as a model REE. Two chemical extractants were tested to estimate the bioavailability of Sm in the soil, its decrease with time and its transfer to the plants. Results showed that DTPA extractable Sm was well correlated with Sm uptake in alfalfa shoots. The experiment pointed out a significant ageing effect since DTPA extractable Sm significantly decreased within 2 weeks in the soils and was significantly lower in the less acidic soil than in the other. The uptake of Sm from soil to alfalfa shoots depended on the soil pH and on the spiking concentration. The soil to plant transfer factor was low (