Contaminação viral e bacteriana em águas subterrâneas na porção aflorante do Aquífero Guaraní, município de Ivoti, RS

Abstract

The water supply of the municipality of Ivoti comes solely from an underground source. The potability of groundwater in the municipality was evaluated by analyzing bacterial (Escherichia coli and total coliforms) and viral (adenovirus, enterovirus and rotavirus) markers for contamination. Twenty-seven water samples from artesian wells, dug wells and springs were collected between February and April 2011. The determination of the most probable number (MPN) of E. coli and total coliforms in 100 mL was performed by the multiple-tube method. Viral markers were analyzed in 500 mL aliquots by polymerase chain reaction (PCR). Total coliforms were found in 66.6% of samples. Contamination found for E. coli was 25.9%, 40.7% for adenovirus and 22.2% for rotavirus. Enterovirus was not found. The presence of coliform bacteria and viruses in the samples indicates fecal contamination of groundwater at the study site, located in the recharge portion of the Guarani Aquifer and suggests the need of caution regarding the use of these water sources for public water supply, individual water catchment and farming.