Fractionation of Phosphorus in Surface Sediments Downstream of a Water Dam in Eastern Algeria

The mobility of phosphorus was examined in sediments sampled downstream Béni Haroun dam located in the northeast of Algeria. Sediment samples were collected in winter and spring 2010. They were characterized by the measurements of pH, electric conductivity, total phosphorus, organic carbon and heavy metals. In addition the infrared analysis was carried out. An analytical procedure involving sequential chemical extractions was used for the partitioning of phosphorus in several fractions. In the first scheme, five sedimentary phosphorus (P) reservoirs were separately quantified: loosely sorbed P, calcium bound P, metal oxides bound P, organic P and refractory P. In the second scheme, the distribution of inorganic phosphorus was estimated after removal of organic matter. The inorganic phosphorus mainly consisted of apatite fraction. The rank order of the different P extracts was the same for the two seasons. The contribution of each fraction was found to follow the order: apatite fraction metals oxides fraction, organic fraction, residual fraction, exchangeable fraction.