Bioaccumulation of 10 trace elements in juvenile fishes of the Lower Parana River, Argentina: implications associated with essential fish growing habitat

This study assessed the concentration, bioconcentration, and bioaccumulation of As, Cd, Co, Cr, Cu, Mg, Mn, Ni, Pb, and Zn in juvenile fishes (Acestrorynchus pantaneiro,Brycon orbygnianus,Cyphocharax voga,Megaleporinus obtusidens,Odontesthes bonariensis,Pimelodus maculatus, Prochilodus lineatus,Salminus brasiliensis, andSchizodon borelli) in the Lower Parana River (Argentina), the most extensive floodplain from the Plata Basin. The floodplain is crucial for the reproduction and growth of various species such asP. lineatus,M. obtusidens, andS. brasiliensis, which complete their life cycle in this environment. In total, 90 individuals were sampled for nitrogen stable isotope, and trace element analysis in muscle tissue, water, and sediment was analyzed. The results show that all the studied species bioaccumulate Cr, Mg, Ni, and Zn. In particular,B. orbygnianusandP. maculatuspresented the highest bioaccumulation factor for Cr. A biodilution of Co through the food chain was observed. No positive correlation was found between element concentration and trophic level, but we observed significant differences between trophic guilds (herbivorous, omnivorous, and carnivorous). Our findings suggest that feeding habits determine trace element concentrations. To establish differential behavior between different species within the aquatic web further studies are necessary, particularly in the floodplain of the Parana, which is a crucial nursery area for most commercially important fishes from the Plata Basin.

Automated summary

This study assessed the concentration, bioconcentration, and bioaccumulation of ten trace elements in juvenile fishes in the Lower Parana River. The results showed that all studied species bioaccumulate certain elements and that feeding habits determine trace element concentrations, with significant differences observed between trophic guilds. Further studies are necessary to understand differential behavior between different species within the aquatic web, particularly in the crucial nursery area of the Parana floodplain.