The Bioaccumulation, Fractionation and Health Risk of Rare Earth Elements in Wild Fish of Guangzhou City, China.

Simple Summary: The limited understanding of the fractionation of rare earth elements (REEs) in fish has hindered the effective use of biomonitoring to assess REEs contamination in aquatic environments. Guangzhou City, which faces widespread emissions of REEs, urgently needs biomonitoring of REEs. Therefore, this study took Guangzhou City as a case study and conducted wild fish collections to investigate the bioaccumulation and fractionation of REEs. Additionally, the associated health risks were evaluated to guide fish consuming. This study confirmed the different REEs bioaccumulation and fractionation among 11 fish species. The bioaccumulation of REEs was found to be a process that could mitigate REEs fractionation. The bioaccumulation and fractionation of REEs among fish with feeding behaviors and living habitats were determined to be specific, so that REEs bioaccumulation and fractionation could be used for tracing the environmental behaviors of fish. Food sources should be treated as the critical regulator in varying REEs bioaccumulation and differentiation. The overall low content of REEs in wild fish shows their consumption should not pose a relevant risk. In this study, the total content of REEs ranged from 1.32 to 67.74 μg/kg, with a predominant presence of light REEs. The ΔEu and ΔCe values, which exceeded and approached 1, respectively, indicated positive Eu anomalies and low Ce anomalies. Wild fish were categorized into high-, medium-, and low-REEs-bioaccumulation groups using cluster analysis. Higher LRs/HRs and ΔEu values, coupled with lower ΔCe values, in fish from the high-bioaccumulation group suggested that increased bioaccumulation mitigated fractionation. Omnivorous fish with higher REEs levels and lower LRs/HRs indicated broader feeding sources may enhance REE bioaccumulation and diminish fractionation. Elevated REEs concentrations and LRs/HRs in demersal fish highlighted a preferential accumulation of light REEs in the benthic environment. Smaller fish with higher REEs levels but lower LRs/HRs were likely associated with complex feeding sources. Regression analysis revealed that fish with lengths and weights of less than 18 cm and 130 g, respectively, were more susceptible to REEs bioaccumulation. Despite higher ADI values indicating a greater risk for children and Pelteobagrus fulvidraco, all ADI values within 70 μg/(kg·d) suggested that fish consumption poses no risk. This study confirmed that the fractionation of REEs in fish can be used to trace their bioconversion. [ABSTRACT FROM AUTHOR]