Considering the increase in agricultural production in Tocantins and in the use of pesticides for such production, 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 triazine, triazole, and benzimidazole classes was analyzed by UHPLC-MS/MS from April 2018 to February 2019. There were four quarterly collections in the dry and rainy periods. The active principles were not found in sediment samples. In soil samples, only the active ingredients tebuconazole and propiconazole were found in the third collection campaign. The active ingredients amethryn, atrazine, carbendazim, epoxiconazole, metconazole, propiconazole, simazine, tebuconazole, and tetraconazole were found in water samples from Formoso River at concentrations of up to 0.286 µg L⁻¹ (atrazine). Although the substances are in low concentrations, we cannot assume that this toxicity is low considering that the risk of a certain pesticide depends on levels and exposure time. Therefore, the action of substances external to the natural environment always threatens biodiversity.

A Plackett-Burman factorial design with 15 experiments was conducted to evaluate the influence of seven factors on lipases production by Fusarium solani. The factors investigated were peptone, tryptone, yeast extract, calcium chloride, potassium phosphate, magnesium sulfate, and copper sulphate. Five fixed variables (cotton oil, pH, temperature, agitation, and time) were maintained and as a response to the enzymatic activity. The concentration of tryptone, calcium chloride, and magnesium sulphate had a significant effect (p < 0.10) on lipase production and was studied consecutively through a complete DCCR (central rotational compound design), to optimize lipase production of the fungi F. solani. After optimization using DCCR, maximum lipolytic activities of 24.84 U/ml were obtained with the use of 10 g.L^-1 tryptone, 3.50 g.L^-1 calcium chloride and 0.50 g.L^-1 magnesium sulfate, 1 g.L^-1 potassium phosphate and 1% soybean oil. The statistical model showed a correlation of 85.67% with the experimental data. The biochemical characterization of lipase showed that the enzyme has a better performance at pH 7 at a temperature of 40 °C, where the statistical model had a correlation of 94.15% with the experimental data. In this way, lipases produced by F. solani have potential for application and use in biodiesel production.

Cerrado biodiversity has been threatened by the increase in agricultural production in the state of Tocantins and the increase in the use of pesticides. This work was carried out in the Formoso do Araguaia region, on the banks of the Formoso River, which is home to about 1,825 indigenous people and is one of the largest indigenous lands in the state of Tocantins, Brazil. The presence of pesticides of the imidazolinone and strobirulin classes was verified, analyzed by UHPLC-MS/MS from April 2018 to February 2019, to assess the impacts of these pesticides on the biodiversity of the study site. After the analyses, five active principles (azoxystrobin, phenamidone, 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. Contamination in the region, where riverine and indigenous people use this water for cultivation, hygiene and food, which is worrying, are exposed to these substances.