RESUMO ABSTRACTUma das preocupações com o uso de lodo de esgoto no solo agrícola refere-se ao risco de poluição das águas subterrâneas causada pela lixiviação de nitrato, o que torna necessário mais pesquisas a esse respeito. One concern about sewage sludge disposal on soils is related to the contamination of groundwater caused by the nitrate leaching due to sludge mineralization, which demands more research on the subject. In this context, the present study aimed to evaluate the behavior of three different doses of biosolids from the sewage treatment station Antas' river of Irati, Paraná State, Brazil. The biosolids were mixed with a Cambisol at the dosages of 2.5, 5.0, and 7.5%, then the samples were inserted into PVC columns with the leaked bottom that allowed the capture of the percolated water to perform the nitrate analyzes. The results showed that contents up to 25 t.ha -1 do not imply a significant increase in nitrate in the percolate, but doses of more than 80 t.ha -1 should not be applied because, according to the regression model found, this would result in harmful doses of nitrate in groundwater . It is recommended that in future studies aspects related to the cation exchange capacity and the nitrogen content in the soil are correlated with the percolated nitrate concentration, since they can significantly affect the ion behavior in the soil horizon.PALAVRAS-CHAVE: Adubação, Lodo de esgoto, Poluição do lençol freático.