Analysis of the relationship between quality of the water from surface springs and occurrence of waterborne diseases in the state of Rio Grande do Norte, Brazil

Abstract

Water characterization through indices consisting of characteristics that can be measured through the analysis of physicochemical and microbiological parameters is useful in environmental surveillance, as well as in the interpretation of possible health risks linked to the use of contaminated water, in addition to contributing to defining the environmental management actions required for water conservation. The objective of this study was to evaluate, through water quality (WQI) and trophic state (TSI) indices, the influence of the quality of public water supply in the state of Rio Grande do Norte on the occurrence of waterborne diseases (WBDs) in its population in seventy municipalities from 2008 to 2016. A hierarchical cluster analysis was performed with the intention of classifying the municipalities, based on the quality of the water consumed and represented through the aforementioned indices. In addition to that, a generalized linear model was used to describe the influence of water quality on the occurrence of WBDs. A geospatial analysis was performed with the objective of describing the priority areas in sanitary relevance causal order. Five clusters were created according to the water quality pattern observed. The Piranhas-Açu and Apodi-Mossoró hydrographic basins were the ones that presented the largest number of municipalities containing springs with the worst indices in terms of water quality and frequency of WBDs during the period under study. A statistically significant difference was established between the water quality found and occurrence of waterborne diseases. Odds Ratio for contracting WBDs up to 5 times higher than those found in places with better water quality were documented. Thus, the findings of this research highlight the usefulness of studying environmental quality, mainly for delineating priority areas for the implementation of environmental and health policies aimed at minimizing the impacts of poor environmental quality on the health of the population.