title: Phosphorus fractions and its release in the sediments of Haihe River, China.
abstract: The amounts and forms of phosphorus (P) in surface sediments of Haihe River, Tianjin, North China, were examined using a sequential chemical extraction procedure. Five fractions of sedimentary P, including loosely sorbed P (NH4Cl-P), redox-sensitive P (BD-P), metal oxide bound P (NaOH-P), calcium bound P (HCl-P), and residual P (Res-P) (organic and refractory P), were separately quantified. The results indicated that the contents of different P fractions in the sediments varied greatly. The total P (TP) contents ranged from 968 to 2017 mg/kg. Phosphorus contents in NH4Cl-P, BD-P, NaOH-P, and HCl-P ranged from 6.7 to 26.6 mg/kg, 54.5 to 90.2 mg/kg, 185.2 to 382.5 mg/kg, and 252.3 to 425.5 mg/kg, respectively, which represented 1.2%-3.2%, 7.7%-13%, 33.3%-48.9%, and 36.2%-54.2% of the sedimentary inorganic P, respectively. For all the sediment samples, the rank order of P-fractions was Res-P > HCl-P > NaOH-P > BD-P > NH4Cl-P. The highly positive relationship between the amounts of P released from the sediments and those in the NH4Cl-P and BD-P fractions, indicated that NH4Cl-P and BD-P were the main fractions that can release P easily.
authors.affiliation: Numerical Simulation Group for Water Environment, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China. sunshujuannk@yahoo.com.cn
authors.forename: Shujuan
authors.initials: S
authors.lastname: Sun
authors.forename: Suiliang
authors.initials: S
authors.lastname: Huang
authors.forename: Xueming
authors.initials: X
authors.lastname: Sun
authors.forename: Wei
authors.initials: W
authors.lastname: Wen
mesh_terms: D002681:China; D004784:Environmental Monitoring / Q000379:methods; D005618:Fresh Water / Q000737:chemistry; D019015:Geologic Sediments / Q000737:chemistry*; D010084:Oxidation-Reduction; D010758:Phosphorus / Q000737:chemistry*; D045483:Rivers / Q000737:chemistry*
chemical_list: D010758:Phosphorus