Integrated environmental risk assessment of rare earth elements mixture on aquatic ecosystems

Rare Earth elements (REE) have become essential in strategical sectors such as high- and green-technologies. Their increasing use human activities worldwide leads to anthropogenic REE releases detectable all compartments of the environment, transforming into emerging contaminants. However, their potential impacts on ecosystems are still poorly understood. In order a comprehensive understanding ecotoxicology properly assess environmental risk, we analysed toxicity three representative (neodymium Nd, gadolinium Gd, ytterbium Yb). Following recommendations European Chemicals Agency, assessed hazard by performing standard ecotoxicological tests freshwater species belonging different trophic levels (algae, crustacean fish). EC50 were calculated using modes expression exposure concentration (based nominal, measured total dissolved concentrations) more accurately determine toxicity. get closer conditions, also tested mixture because them occur naturally environment. Moreover, added organic matter (DOM) test medium DOM is ubiquitous drives speciation systems. The Results showed that significantly reduced bioaccumulation toxicity, probably formation non-bioavailable REE-DOM complexes. algal was most sensitive REE. Despite slight differences between Gd Yb behaviour bioaccumulation, exhibited comparable additive effects organisms. Thus, considered uniform group and, for first time, used values concentrations risk (instead considering separately). results revealed currently limited wastewater treatment plants, industrial mining activities, where released quantities can induce severe damage exposed risks likely widespread future expected increase.