Pollutants of the Guaribas river water and their toxicogenic effects

Abstract

Tropical rivers used for water supply, irrigation and tourism have effects on anthropic activities. This study aimed to evaluate the presence of different pollutants in the aquatic environment of the Guaribas river water and their possible cytogenotoxic effects. For this, the presence of heavy metals and cyanobacteria along with the possible cytogenotoxic effects in the aquatic environment were evaluated at the city of Picos-PI/Brazil, of its upstream, within and downstream regions. The results suggest that the electrical conductivity, total dissolved oxygen and solids, turbidity, color, chlorine and total phosphorus were above the allowed levels by the country's legislation, especially at the points associated with the main city. Water collected from the within and downstream regions showed a significant cytotoxic and mutagenic effects, regardless of seasons, where a positive correlation was observed between the genetic damage and heavy metal contents. Furthermore, mutagenic cyanotoxins were also found in the samples. These results pointed out that the Guaribas river contains physical and chemical contaminants, and cyanotoxins, that can cause genetic damages, suggesting a bad impact on the aquatic ecosystem, human and other animals directly or indirectly dependent on it. In conclusion, adequate attention is required to establish toxicogenic biomonitoring programs for the other tropical rivers in Brazil.