Rare earth elements in two highly consumed fish species from an anthropogenically impacted estuary in Southeastern Brazil

Rare earth elements (REE) comprise seventeen chemical elements, fifteen belonging to the lanthanide series and two to the transition metal group. Found in several matrices such as plants, water, soil and animals, some due to anthropogenic actions. REE toxicity has not yet been elucidated, although preliminary studies indicate that bone calcium can be replaced by these elements, as they present the same oxidation number. In addition, some REE also display carcinogenic properties and the ability to cause cytotoxicity and genetic damage through oxidative stress processes. Considering the existence of several contamination sources and significant artisanal fishing activities surrounding Sepetiba Bay, the aim of this study was to quantify REE in two of the most caught and consumed fish species in the area, mullet (Mugil cephalus) and whitemouth croaker (Micropogonias furnieri). Ten muscle samples from each species were caught in the Pombeba area, located in Sepetiba-Itaguaí Bay, Rio de Janeiro, and analyzed by inductively coupled plasma mass spectrometry (ICP-MS). Analytical quality control was performed by the analysis of a certified reference material (DORM-4, NRCC, Canada), with recoveries ranging between 89 and 117 %, considered adequate for this type of study. Eight REE (Y, Er, La, Ce, Pr, Nd, Sm and Eu) were detected in three M. furnieri samples and four REE (Y, La, Ce e Nd) in five M. liza samples. Some of the detected REE have been reported as leading to deleterious cellular effects in several organisms. Although detected at low concentrations (ranging from 0.001 to 0.007 mg kg-1 wet weight) compared to the only existing legal reference in China, which stipulates a maximum limit of 0.7 mg kg-1 for the sum of all REE in animal feed, monitoring of the surveyed area, in order to adequately assess these elements and carry out public health risk assessments, is required.