Toxicological assessment of aquatic environments: the importance of sediment analysis

Abstract

Water resources contamination can affect human and environmental health. In aquatic environments, sediment is relevant to biota survival. However, most contaminants are stored in this matrix, posing risks to organisms. Acute sediment and surface water toxicity was evaluated using the Vibrio fischeri bacteria, using the Microtox® system. Samples were collected along the Pardo River, São Paulo, Brazil, during the rainy and dry seasons. In sediments, significant percentages of CE20 were detected, with predominance of Toxic and Very Toxic concentration. Acute bacterial toxicity was not found in the analysis performed with the water samples. In conclusion, the presence of toxic compounds in the Pardo River sediment indicates that there is an imminent environmental impact and the accumulation of these contaminants in this matrix is more significant when compared to water. Therefore, the sediment samples analyzed showed that this matrix more accurately portrays the quality of the ecosystem.