Ecotoxicity and water quality assessment of the Reconquista River (Buenos Aires, Argentina) by standardized bioassays on early developmental stages of a native amphibian (Rhinella arenarum)

Abstract

This work evaluated the water quality of the middle and lower basin of the Reconquista River, one of the most affected water bodies in Argentina, by physicochemical and ecotoxicological parameters. Physicochemical parameters were analysed in situ and in the laboratory in water samples from 10 sites distributed in the basin. Standardised toxicity bioassays were carried out with embryos and larvae of the native amphibian, Rhinella arenarum, exposed to dilutions of the surface water samples for a chronic (504 h) period. water quality indexes (WQI) revealed a marked deterioration of the water and evidenced a clear spatial pattern with higher contamination at the central section which also caused a higher significant mortality in both embryos and larvae. The results demonstrate the substantial degradation of this water body and highlight the detrimental impact on the biota and aquatic ecosystem. These findings emphasise the need for an integrated approach to environmental concerns, using multiple indicators and information as an integrative approach of environmental quality assessment.