Fracionamento de fósforo em sedimento de reservatórios raso do semiárido brasileiro

Abstract

In the middle of natural resources, water is the most important, as it is an essential element of life, as for all activities developed by man. Reservoirs have been significantly modified due to the multiple environmental impacts arising from human activities, both by direct means, through domestic and industrial dumping, as well as by indirect means, brought by rainwater through the surface runoff. Due to the multiple environmental impacts such as eutrophication, countless reservoirs and lakes in the world have already lost countless environmental services, from human supply, the maintenance of aquatic life and tourism and leisure activities. The objective of this work was to evaluate the fractionation of Phosphorus in sediment from shallow reservoirs in the Brazilian semiarid region . Physico-chemical parameters of the water in the monitored environments were analyzed. The Trophic State Index was determined, the total phosphorus and orthophosphate contents of the water in the monitored reservoirs were quantified, the total, organic and inorganic phosphorus contents in the sediment were quantified and the fractionation of the inorganic phosphorus was performed, determining its non-apatitic fractions. The reservoirs had hot water (> 25 ºC), turbid, with low values of transparency (<0.4 m), alkaline (pH> 8.0) and with high electrical conductivity and with high electrical conductivity. Due to the high concentrations of phosphorus in the water, above 30 µg / L, the reservoirs were classified as strophic (> 54). The sediments registered levels of total phosphorus greater than 1000 mg kg-1, with a predominance of apatitic inorganic phosphorus in all three reservoirs. The results found attest to the environmental vulnerability to which these environments are subjected, which can compromise the use of the waters of these reservoirs for different purposes.