BILLINGS RESERVOIR (BRAZIL): CHEMICAL STUDIES ON WATER AND CHEMICAL AND MORPHOLOGICAL STUDIES ON ZEBRAFISH GILLS

Ednilse Leme,Thiago Berti Kirsten,Paula Da Silva Rodrigues,Maria Martha Bernardi,Maristela Dutra-Correa,Welber Senteio Smith

doi:10.20950/1678-2305/bip.2021.47.e649

Abstract

Previous study of this research group revealed that water from the Billings reservoir (Brazil) intended for human use (water supply and seafood) has microbiological contamination and causes lethality and brain and behavioral impairments in zebrafish. The objective of this study was to understand what have induced these impairments in the animal model. Chemical analyses on water samples from Rio Pequeno (RP), Rio Grande (RG), and Bororé (BO) rivers, as well as chemical and morphological analyses on zebrafish gills exposed to those waters were performed. Waters samples from RP, RG, and BO presented high levels of phosphorus. BO water and fish gills exposed to this water presented high levels of nitrogen. RG water caused potassium contamination in gills. Phosphorus, nitrogen, and potassium are indicators of anthropogenic pollution. RG water and fish gills exposed to this water presented low levels of calcium, which might be an indication of chemical imbalance that could lead to health problems in aquatic animals. RG and BO waters resulted in zirconium contamination in gills. BO water induced respiratory lamellae thickening in the gills, which may be the underlying mechanism for the observed hypoxia. In conclusion, behavioral, brain, and respiratory defects observed previously were induced by chemical and morphologicalb disturbances due to anthropogenic pollution in the Billings reservoir.

Highlights

The Billings reservoir is located in the metropolitan area of São Paulo, Brazil, and is the biggest reservoir of the state (Hortellani et al, 2013)
Rio Grande (RG) water and fish gills exposed to this water presented low levels of calcium, which might be an indication of chemical imbalance that could lead to health problems in aquatic animals
BO water induced respiratory lamellae thickening in the gills, which may be the underlying mechanism for the observed hypoxia

Summary

Introduction

The Billings reservoir is located in the metropolitan area of São Paulo, Brazil, and is the biggest reservoir of the state (Hortellani et al, 2013). Reservoir (Rodrigues et al, 2010) Nowadays, activities such as energy generation, recreation, amateur and commercial fishing, and water supply are commonly performed in the Billings reservoir (Gemelgo et al, 2009; Wengrat and Bicudo, 2011). The deviation of the Pinheiros and Tietê rivers (Sao Paulo, Brazil) to the Billings reservoir to increase the hydroelectric power have increased the pollution of its waters (Wengrat and Bicudo, 2011). RG and Taquacetuba arms of the Billings reservoir are used for water supply of 1.6 million people, with the possibility of supplying more than 4.5 million people (Wengrat and Bicudo, 2011; SABESP, 2015b)

Objectives

Methods

Results

Discussion

Conclusion