Integrated biomonitoring of a hydrographic basin with socioeconomic importance for a metropolitan region in the Northeast of Brazil, with the zebrafish model system
ecotoxicology, contaminants, surface water, water quality, Danio rerio.
There is a growing number of studies that point to the effects of anthropogenic activities on the environment, especially in aquatic ecosystems. The consumption demands of the world's population have negatively affected water resources, due to the reception in the water bodies of of personal hygiene products, agricultural products, domestic and industrial effluents. In this work, the zebrafish (Danio rerio) model system was used to assess the environmental quality of a hydrographic basin in the metropolitan region of Maceió, in northeastern Brazil. Water samples were collected according to specific protocols in three different locations (P1, P2 and P3), between the source and the mouth of the Pratagy River, with different degrees of anthropization and in two periods, March and June 2022. The samples were destined for the determination of the physical-chemical parameters of the water and of different classes of contaminants, as well as for the embryolarval toxicity test with zebrafish (ZELT), during 144 hours, with the analysis of lethal and non-lethal biomarkers, cardiotoxicity and neurotoxicity. Among the persistent pollutants analyzed so far, it was detected in all sample points the flame retardant polybrominated diphenyl ether (PBDE28); and the pesticides Endosulfan sulfate, Dichlorodiphenyltrichloroethane (4,4 DDT) and Endrin ketone (END_KE). Regarding the mortality rate, only a significant increase was observed in the P3 of the first sampling. There was no change in the hatching rate between the periods and sampled points.For the number of heartbeats, a significant difference was observed between the periods collected, but not between the locations.The data set evaluated corroborate the negative influence of anthropic actions on the Pratagy River basin and that can affect the survival and physiology of aquatic organisms.The quantification of new classes of contaminants and new biomarkers in the collected samples will allow inferences about the real environmental quality of this aquatic environment.