Wetzl, Ruby J.
Rare earth and trace element geochemistry in Ontario agricultural soils
Agriculture may result in soil disturbances, including contamination by rare earth elements (REE) and trace elements (TEs) from agricultural inputs (e.g. fertilizers, pesticides). Regulations concerning agricultural inputs currently do not consider TE background concentrations, concurrent use of inputs, and emerging contaminants. Therefore, they may not sufficiently protect against TE contamination, including that of REEs as emerging contaminants. The objective of this work was to assess the concentration and distribution of TEs and REEs in agricultural soil and whether agricultural management alters soil geochemistry. Fourteen farms were sampled in southeastern Ontario, and the geochemistry of soils was analysed using ICP-MS and ED-XRF. Trace element concentrations exceeded environmental safety standards in some sites, including those characterized by historical contamination or elevated background concentrations. Concentrations of REEs are reported in Ontario agricultural soils, and the normalized REE values indicated enrichment of the middle REEs. Geographic location drives site geochemistry more than agricultural management.
Author Keywords: agriculture, phosphate fertilizer, rare earth elements, soil geochemistry, trace elements