Estresse toxicológico em um rio altamente impactado no ambiente portuário de Santos, SP

Abstract

There are many stilts and industry, which discharge sewage, domestic garbage and industrial effluents in the Pouca Saude River from the port environment of Santos, Sao Paulo (SP) State. However, ecotoxicological studies in this river are rare. In this study, we seek to fill this gap by analyzing physicochemical, toxicological, and chemical conditions. Surface water and sediment samples were collected at 2 sampling sites with riparian community activities and industrial activities in the summer, autumn, winter and spring. The parameters analyzed were pH, alkalinity, turbidity, salinity, oils, greases, dissolved oxygen (DO), toxicological and cytotoxicity with mitotic index (MI) of onion roots using Allium cepa roots, and concentration of Pb, Zn, Hg, Ni and Cd. Our results showed alterations in the DO, turbidity, oils/greases and reduction of MI when compared to the respective control. Ni and Zn in sediment samples presented concentrations exceeding levels occasionally associated with adverse biological effects "threshold effect level". These results suggested that the water quality of the Pouca Saude River is influenced by both presences of heavy metals contamination and the seasons, i.e. by the tide. Thus, the toxic potential monitoring carried out in this study is of paramount importance to this river.