1. Department of Environmental Engineering, Universidade Estadual do Centro-Oeste, PR 153, km 07, Riozinho, P.O. Box 21, 84500-000 Irati, PR, Brazil
2. Department of Hydraulics and Sanitation, the São Carlos Engineering School, São Paulo University, P.O. Box 359, 13566-590 São Carlos, SP, Brazil
3. Department of Environmental Chemistry, Federal University of Tocantins (UFT), Campus Gurupi, P.O. Box 66, 77402-970 Gurupi, TO, Brazil