Phosphorus speciation in the surface sediment and river water from the Orontes (Asi) River, Turkey.

The paper presents the results of the distribution of phosphorus bioavailability (total, organic, and inorganic phosphorus) in surface sediment and river water from the Orontes (Asi) River (Samandag, Antakya, Turkey) in March 2008. Speciation of inorganic phosphorus was carried out using a method on sequential extractions, with each releasing four forms of inorganic phosphorus-loosely sorbed phosphorus, phosphorus bound to aluminum (P-AL), phosphorus bound to iron (P-Fe), and phosphorus bound to calcium (P-Ca). Total phosphorus concentrations are, on average, 3.724 mg/L and 312.30 mg/kg dry weight in the river water and surface sediment, respectively. The interstitial water of the surface sediment contains less than 1% of the surface sediment's total phosphorus pool. The most abundant form of inorganic phosphorus is P-Ca. Relative abundances of the remaining phosphorus forms both in surface sediment and river water follow the order P-Al > loosely bound-P > P-Fe.