Avaliação dos parâmetros físicos e químicos e da presença de metais traços em águas do rio Gramame-PB

Abstract

Water is a necessary constituent for the life of all organisms. However, human activities cause significant impacts on aquatic ecosystems, deteriorating water quality through the discharge of domestic, industrial and agricultural effluents. Among the pollutants, the concentrations of heavy metals are rapidly increasing to an alarming level, being a cause for concern, as it affects the environment as well as human health. The use of voltammetric techniques has been widely applied in several areas of knowledge, subsidizing the obtaining of data on characteristics of organic and inorganic species of interest. This study aims to evaluate the physical and chemical parameters, as well as the presence of Cd, Pb, Zn and Cu by voltammetric method in three points of the Gramame River and to compare them with the values established by CONAMA Resolution 357/2005 during the months of August and November 2019. The physical and chemical parameters analyzed were dissolved oxygen, temperature, pH, total dissolved solids, nitrite, nitrate and ammonia. For heavy metals, square wave anodic stripping voltammetry was used, adapted from the methodology of Anastasiadou and collaborators. The anthropic actions surrounding these sampling points influenced the physical and chemical parameters in the Gramame River. Oxygen concentrations and pH in certain periods were not in accordance with what was allowed. For the trace metal research, it was possible to observe, through the development of the methodology with the adaptations to the use of the carbon paste electrode modified with bismuth film, a wide range of work for simultaneous analysis of Zn, Cd, Pb and Cu with low detection limits in the order of μg. L-1, whose application to the Gramame River water samples provided results below the detection limit of the method, with average recovery levels in the range of 61.0 to 100%. In view of this, it can be concluded that the limits delimited in the Resolution are important political instruments for monitoring and using voltammetric methods that use modified electrodes constituted by a tool considered in test areas related to metal research, since it presents high sensitivity and analytical speed.