Tracing Rare Earth Element Sources in Ucides cordatus Crabs by Means of Sm-147/Nd-144 and Nd-143/Nd-144 Isotopic Systematics

This study tested for the first time Sm-147/Nd-144 and Nd-143/Nd-144 ratios as tracers of rare earth element (REE) sources in semi-terrestrial organisms from a subtropical estuary affected by fertilizer industry activities. The isotopic composition of claw muscles and shells of male crabs (Ucides cordatus) were obtained by thermal ionization mass spectrometry, and provided contrasting signatures incorporated from the physical components by the biota. Our findings showed that crab shells had isotopic compositions similar to seawater, while the claw muscles incorporated the isotopic signature of sediments contaminated by fertilizer. The isotopic ratios (Sm-147/Nd-144 and(143)Nd/Nd-144) proved that the anthropogenic source is transferring contaminants to the crabs, emerging as a reliable tool to diagnose REE pathway and source to the biota in impacted environments.