Hidrochemical analysis and the application of different groundwater quality assessment methods in coastal aquiferos in Osorio – RS

Abstract

This work aimed to analyze the groundwater quality of driven-point wells, which capture water from unconfined aquifers in the Osório region (RS), and to evaluate the application of different groundwater quality indices. For the development of the study, collection of groundwater samples in 15 driven-point wells, interpretation of physical-chemical and bacteriological data, and ap-plication of water quality were carried. The evaluation of the results indicated that the groundwater of the region mostly presents low concentrations for the main cations and anions, low values of pH and electrical conductivity. The comparison of the results of the analyzes with the Maximum Allowable Values of Ministry of Health No. 2914/11 indicated the existence of quality problems in 14 wells caused by changes in different parameters, such as pH, ammonia, iron, color, aluminum, manganese, turbidity, total coliforms, and E. coli. The application of the Groundwater Quality Index indicated the occurrence of 4 wells with water of poor quality, 2 of good quality and 9 of high quality. The calculation of the Relative Risk Index evidenced the occurrence of 4 wells which presented higher values. The Health Risk Assessment indicated the occurrence of 2 wells that presented non-Carcinogenic Risk. The analysis of the application of different indices demonstrated the existence of a discrepancy in the results, since the application of each of the indices different parameters are used. Thus, in groundwater quality assessment studies, more than one type indices should be used, so that it is possible to identify and evaluate more precisely the changes in the quality of this water resource.

Keywords

• Aquífero livre. Qualidade da água. IQUAS. IRR. Avaliação de risco.