Temporal and spatial evaluation of the surface water quality of the river Desquite watershed, Santa Catarina

ABSTRACT

The objective of this study was to evaluate the environmental impact of land use and occupation on the water quality of the Desquite river basin, using CONAMA Resolution n^o 357/2005, as beacon legislation. Water samples were collected and the physical-chemical parameters were determined: temperature, pH, electrical conductivity, DO and TDS, with a multiparameter probe; COD, total phenols, total phosphorus and ammonia (NH₃) with a Photocolorimeter; and the metals Cd, Pb, Cr, Ni and Cu were determined by Continuous Source High Resolution Atomic Absorption Spectrometry (HR-FC EAA). Based on the comparative legal order, the samples presented values above the maximum permitted values for the parameters total phosphorus, ammonia (NH₃) and Cr. Changes were also observed in the parameters: OD, total phenols, COD and Cd. At the end of a year of follow-up and sampling campaigns, it was concluded that the Desquite river would be classified according to the limits established for class IV of CONAMA Resolution n^o 357/2005, the main changes in water quality occur in the areas of permanent preservation with absence of vegetal cover or in the releases of domestic effluents and solid residues in these places or directly in the bodies of water.

Keywords:
Class IV; hydrographic basin; legal order; quality of surface water