WATER QUALITY IN POTY RIVER TO HUMAN CONSUMMATE AT TERESINA, PIAUI STATE, BRAZIL

Abstract

The water quality of the Poty river was evaluated, to human consummate at Teresina, PI, to know its current conditions and to show the possible impacts, seeking to dispose data to the competent organs, for conservation and rational use of this resource. It was collected samples of water in the river in 10 georeference points, of the São Paulo Residential curve (southeast zone) until its mouth in the Parnaiba river (north zone), in an approached course of 23,7 km, of June to December of 2004. It was verified in field, that the concentrations of OD are below the pattern, in 80 % of the showed points (Class 2). It was detected increase of the Chlorophyll it (6,98 to 16,09 µg L^-1) of September to the second fortnight of November. It was verified oscillations in the concentrations of HCO3 (1,68 to 1,91 mmolc L^-1) along the showed points. The largest indexes of CF and CT happened, above all, in the second fortnight of November (1.368 and 3.498 NMP 100 mL^-1) respectively. It was observed impacts in the spring, such as, garbage accumulation in the margins, sand of banks, exposed soils, ciliary forest degradation, small agriculture, minerals dredge operation (August to December), erosion and sanded area, in several spaces. It was verified values out of the recommended limit by CONAMA for OD, NH₃ and CF, inferring concern to the aquatic balance, in function of the domestic effluent of release intense in the area.