Limnological evaluation in the Limoeiro River Basin in State of São Paulo, Brazil

Abstract

The aim of this study was to evaluate water quality in the Limoeiro River Basin in the West of São Paulo State, Brazil, from the perspective of the Water Quality Index for the Aquatic Life Protection (IVA). The research was carried out through Bibliographic Research, Fieldwork, and Laboratory Analysis. Evaluations were conducted to construct the IVA (Chlorophyll, Phosphorus, Dissolved Oxygen, pH, Cadmium, Chromium, Copper, Lead, Nickel, Zinc, Phenols, Surfactants) for two periods (2019, rainy and dry seasons) at 5 strategic points within the basin. During the rainy season, 43% of the assessed parameters exceeded the legal limits set by CONAMA Resolution 357, while in the dry season, the proportion was approximately 60%. In the Rainy Season, the Limoeiro River presented a IVA weighting coefficient of 4.1 (“Regular”), whereas in the Dry Season, the score was 7.7 (“Terrible”). This classification for both seasons indicates scenarios that may be structured by a variety of factors, either of natural or anthropogenic origin. Unsuitable conditions for the maintenance of aquatic life were observed. According to IVA and the standards of the São Paulo State Environmental Agency (CETESB), these conditions highlight that anthropogenic activities have caused environmental impacts at the investigated points.