The use of water from streams depends on their quality in often degraded by excessive nutrient loads such as phosphorus. The study of this nutrient by a method of sequential analysis in sediments aims to provide information on environmental quality, while determining the form of bioavailable phosphorus.
This work aims to put the focus on the different forms phosphorus could be found in the aquatic sediments of the main rivers in the region of Meknes (Morocco).
The determination of total phosphorus level in sediments is made using spectrophotometry applied on the supernatant after mineralization of the sediment with (H2SO4/K2S2O8) according to ammonium molybdate method using ascorbic acid as reagent. The chemical fractioning of phosphorus in the sediment is done following the Golterman fractionation scheme that uses EDTA as specific chelating agent that extract the mineral fraction without disturbing the organic phosphorus by adjusting the pH of extracting solutions to that of the sediment.
This scheme will allow us to determine the proportions of five forms of phosphorus: water-soluble phosphorus (o-P), iron-bound phosphorus (Fe (OOH)-P), calcium-bound phosphorus (CaCO3-P), acid-soluble organic phosphorus (ASOP) and residual organic phosphorus (ROP).
The results of these extractions showed that the sediment phosphorus of studied samples is mainly under its mineral form [Fe(OOH)-P + CaCO3-P]. These forms represent around 77% of total phosphorus with a predominance of the CaCO3-P fraction. The organic forms (ASOP + ROP) represent only 23%.