Resumo O abastecimento de água do município de Ivoti provém unicamente de origem subterrânea. A potabilidade da água subterrânea do município foi avaliada através da análise de marcadores bacterianos (Escherichia coli e coliformes totais) e virais (adenovírus, enterovírus e rotavírus) de contaminação. Vinte e sete amostras de água provenientes de poços artesianos, poços cavados e fontes foram coletadas entre fevereiro e abril de 2011. A determinação do número mais provável (NMP) de E. coli e coliformes totais em 100 mL foi realizada pelo método dos tubos múltiplos. Os marcadores virais foram analisados em alíquotas de 500 mL por reação em cadeia da polimerase (PCR). Coliformes totais foram encontrados em 66,6% das amostras. A contaminação encontrada para coliformes termotolerantes foi de 25,9%, 40,7% para adenovírus e 22,2% para rotavírus. Nenhuma amostra apresentou enterovírus. A presença de coliformes e de vírus nas amostras indica contaminação fecal da água subterrânea no local de estudo, situado na porção aflorante do Aquífero Guarani e alerta para a necessidade de precaução quanto ao uso destes mananciais para abastecimento público, captação individual e cultivo de hortaliças.

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.

Viral gastroenteritis and other waterborne diseases are a major concern for health in Brazil. A number of studies were conducted about the presence of viruses on water samples from Brazilian areas. However, the knowledge about the occurrence of viral contamination of drinking water sources in rural settings of the country is insufficient. On the present work, 15 samples from 5 dairy farms located at the municipality of Tenente Portela were collected and analysed for the presence of human adenoviruses (HAdV), as well as human enteroviruses (EV) and rotaviruses (RV). HAdV was present on 66.66% of the water samples, and have been found in all samples from artesian wells and springs, which are used as sources of drinking water for the individuals inhabiting those farms. EV and RV found only in one sample each. The detection rates of HAdV on the water from these dairy farms are alarming and point towards a situation of elevated environmental contamination by fecal microorganisms of human origin and poor basic sanitation conditions.