The biodiversity of the Cerrado has been threatened by the increase in agricultural production in the state of Tocantins and by the increased use of pesticides. This region of Formoso do Araguaia, it is home to around 1,825 indigenous people and is one of the largest indigenous territories in the state of Tocantins This work investigates the levels of pesticide residues in different environmental compartments (soil, sediment and water samples) of the Formoso River in the state of Tocantins, Brazil. The presence of pesticides of the imidazolinones and strobirulins classes by UHPLC-MS/MS were analyzed from April 2018 to February 2019, which helped in an evaluation of the impacts of pesticides on the biodiversity of the place of study. After analysis, five active principles (azoxystrobin, fenamidone, imazethapyr, tricyclazole, and trifloxystrobin) were detected in the water matrix, two active principles (azoxystrobin and tricyclazole) in the soil matrix, but no active principle was detected in the sediment matrix. In the region of the Parque do Araguaia Indigenous Lands, people who use this water for cultivation, hygiene and food, which is worrying, are exposed to these substances.