Water Quality and Access in Isabela: Results from a Household Water Survey

Abstract

AbstractContaminated water represents one of the major health threats for the inhabitants of Puerto Villamil, Isla Isabela, Galápagos. Water supply on this island depends on brackish groundwater as the main drinking water source. Historically, drinking water quality has been one of the main concerns of the population. This has encouraged the habit of using bottled water as a drinking source and even a cooking water source for most people. In July 2019, an observational pilot study was conducted, focused on analyses of survey data and physicochemical and microbial (total coliforms and Escherichia coli) water samples from 35 households spread across town and from the municipal desalination water treatment plant. Two samples were taken at each household, one from tap water and a second from the main drinking water source. In situ parameters such as pH, conductivity, dissolved oxygen, temperature, and salinity were recorded at each sampling point. Results show minimal treatment by the municipal desalination plant with testimonial evidence that current infrastructure is insufficient to meet the water demands of Puerto Villamil. All households had total coliforms confirmed in the tap or drinking water source (n = 35), indicating environmental contamination. Ten households exceeded national and international guidelines for E. coli coliforms in drinking water, but most tap and drinking water samples tested positive for E. coli at concentrations <10 MPN per 100 mL. Physicochemical measurements indicated high salinity, conductivity, and pH in tap water piped to households was similar to that of high levels of water at the treatment plant, although within international guidelines. This pilot study provides comparisons of the water environment on Isabela to that of other islands in the Galápagos and insights on future actions that authorities and inhabitants can take to improve water security.KeywordsWater securityWater qualityHeavy metalsSalinityHousehold survey