Aplicação da geoquímica inorgânica na investigação da contaminação ambiental de sedimentos do Rio Ipojuca, Caruaru/PE, Brasil.

Abstract

In the study about contamination of aquatic environments, the chemical characterization of sediments in the context of inorganic geochemistry with metal determination can provide important information, as the historic contamination of the aquatic ecosystem, leading to the knowledge of quantity, quality, period and effects caused by that contamination, most often from anthropic activities. The current study aims to achieve the quantification of metals by Inductively coupled plasma optical emission spectroscopy (ICP-OES) of sediments from the Rio Ipojuca, in the stretch of the municipality of Caruaru, state of Pernambuco, in order to identify the level of contamination through these elements, based on the values of the quality guide described on the resolution of CONAMA nº 454/2012. The values of Cr, Cu, Pb and Zn revealed that the sediments are with values higher than the limit value of the Level 1 quality's reference (VRQ1) for the most samples, which indicates that they are above the determined level from which there is less probability of adverse effects on the biota. Furthermore, for the concentration of Cr and Zn, two of the samples were found with concentrations higher than the limit value for the Level 2 quality's reference (VRQ2), leading to regions with values above the determined which there is a greater probability of adverse effects on the biota. In order to follow the resolution of CONAMA nº 454/2012, nine of the ten sediments studied fit the condition in which there is a need to carry out additional experiments, as ecotoxicity tests, due to the values above VRQ1 and VRQ2 indicate a potential contamination. Through the multivariate statistics analysis (PCA e HCA/heatmap) we have found a visualization that show a trend from less contaminated to more contaminated sediment, in which the most contaminated are located close to the urban centers of Caruaru City, pointing out that human activities are responsible for this environmental contamination. Thus, it is possible to conclude that there is a broader need for environmental monitoring of the Rio Ipojuca regarding heavy metal concentrations in the aquatic system, in a way that there is a continuous assessment of its quality and the harmful effects that the contamination may represent.