The Parati River contributes to the Babitonga Bay water complex, but the contents of the bay also influence the river during periods of inverted currents. In this study, the water quality along four stretches of the Parati River and Babitonga Bay was evaluated using chemical (physico-chemical and chromatographic analysis), microbiological (fluorescein diacetate hydrolysis) and ecotoxicological (Lumistox) methods to assess the reciprocal influence of the waters of this river-bay system. In addition, the most appropriate type of analysis for the monitoring of the estuarine region of the Parati River was identified. The results of six sampling campaigns showed that the type of contaminants and their levels varied temporally and spatially and thus the water quality also changed. Anthropogenic activity, such as banana cultivation and the release of sewage into the water system, is the primary cause of the contamination that affects the quality of the water in the Parati River estuary, which is a crucial ecological niche for the reproduction of various marine species. The ecotoxicity tests with Aliivibrio fischeri conducted to evaluate the water quality showed an integrative response, and the ecotoxicity data indicated that the Parati River does not have a significant influence on the water quality of Babitonga Bay.
Keywords: Babitonga Bay; Parati River; Water quality; environmental impact.