Avaliação estatística da evolução temporal dos índices de qualidade da água (IQAS) obtidos desde o ano de 2008 pelo programa monitora para o município de Salvador, Bahia, Brasil

Abstract

To address the management demand of the water resources within the state of Bahia, the environmental agency named as Instituto do Meio Ambiente e Recursos Hídricos (INEMA) has created a program called Programa Monitora, which evaluate water resources to calculate the Water Quality Index (Índice de Qualidade da Água – IQA) of the state. The purpose of this current study was to evaluate the temporal evolution of all IQAs presented from 2008 to 2016 for the sampling points collected at the municipality of Salvador, Bahia, Brazil, by using a tool for statistical analysis named as GSI Mann-Kendall Toolkit. The statistical method applied to this study has inserted data obtained from the Programa Monitora within the abovementioned statistical tool to obtain the temporal evolution for all the 28 sampling points considered as representative, that were collected in 23 sampling campaigns. The results showed that 22% of the IQAs presented an increasing or probably increasing trends along the years, 14% presented decreasing or probably decreasing trends, 32% presented a stable trend and 32% presented no defined trend associated to the results. Overall, it is possible to conclude that the evolutionary trends obtained may contribute to the definition of priority action points by the committee responsible for the management of such water resources. Additionally, future studies may be held using the physical chemical parameters individually and using parametric statistics to evaluate these results considering the external influences that were not evaluated by the current study.