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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 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 Haihe sediments varied greatly. The total P (TP) contents ranged from 968 to 2 017 mg/kg. 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, which represented 1.2%-3.2%, 7.7%- 13%, 33.3%-48.9%, and 36.2%-54.2% of the sedimentary inorganic P. 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 NH4Cl-P and BD-P, indicated that NH4Cl-P and BD-P were the main fractions that can be released easily.