Rare earth elements (REEs) are central in several critical technologies; their use is constantly increasing as is their release into the environment. For this reason, it is important to investigate REE concentrations in different matrices to evaluate human exposure and environmental risk of these emerging contaminants.

REEs were measured by ICP-MS in matrices of terrestrial (plant feed, fruit, honey, wildlife livers) and marine origin (seaweeds, zooplankton, bivalves, fish) collected from Northwestern Italy. Highest REE concentrations were measured at low trophic levels, both in terrestrial and marine environments, such as plants (ΣREE 1.8 mg kg⁻¹) and seaweed (ΣREE 12 mg kg⁻¹), the major source of exposure and transfer of REEs to food webs. REE concentrations were several orders of magnitude lower in fruit, honey, and livers from terrestrial wildlife, suggesting a negligible risk of exposure by these matrices. Marine biota, such as bivalves (ΣREE 0.16 mg kg⁻¹) and fish (ΣREE 0.21 mg kg⁻¹) may constitute a pathway for human or animal dietary exposure.

The study confirmed that REEs have low potential for biomagnification, but instead are subject to trophic dilution. However, given the numerous sources of dietary introduction of REEs, they should be monitored for a possible harmful cumulative effect.

Owing to the scarcity of data regarding REEs worldwide, our results contribute to assessment of the occurrence of these emerging contaminants.