Water safety for human supply in rural communities: a risk-based approach for the Brazilian semiarid region

Abstract

The existence of water in sufficient quantity and quality is directly linked to the maintenance of public health. In this context, the aim of this study is to assess the quality of water used for human consumption in the rural area of Campina Grande, Paraiba, Brazil. The study also examines the sanitation conditions that could lead to potential health risks for the population residing in these areas, due to water contamination. As a result, alternative collective supply solutions (ACS) and individual supply solutions (AIS) were analyzed, starting from water collection to storage at households. A total of 10 sampling points were used, comprising 5 cisterns and 5 water trucks. The physical and chemical analyses included: free and combined residual chlorine (FRC), turbidity, color, pH, electrical conductivity, and the presence of total coliforms and Escherichia coli. Subsequently, a product and process risk analysis was conducted using the Failure Mode and Effect Analysis (FMEA) method, which enabled the identification and evaluation of key failure risks and their effects. The physicochemical and microbiological results demonstrated that the waters were unsuitable for human consumption at all collection points. Furthermore, the main hazards identified for the product (water), following the classification of risk priority levels, were the presence of E. coli, the presence of total coliforms, low concentration of FRC, high apparent color, and for the process, the absence of rechlorination in the water consumption reservoir. Ultimately, it was possible to diagnose the non-compliance of the waters from alternative supply solutions with Ministry of Health Ordinance No. 888 of 2021. Additionally, the risk analysis proved to be a highly efficient method for this supply method, successfully pinpointing the main vulnerabilities of these waters to contamination.