| Phosphorus (P) is a vital element and its cycling in natural work(?) achieved by the interaction between particulate matters and water among earth-river-sea, which is significant to keep the balance of river-sea ecosystem therefore particulate matters in the waters have very important influences for phosphorus to achieve the cycle of the earth and chemistry. In this papo(?) surface sediments from the upper reaches of the Yellow River were studied by following parts:①The contents and their distribution characteristics of all kinds of phosphorus forms and totle phosphorus(TP), inorganic phosphorus(IP), organic phosphorus(OP), totle nitrogen(TN), totle carbon(TC) were investigated in the sediments, and the relativity between their contents and grain sizes was analyzed; The contents of potential bioavailable phosphorus(BP) in the sediments were estimated;②P adsorption characteristic in sediments and EPCo of P adsorption/desorption were researched. The results have shown that:1 Contents and distribution of TP, all foms phosphorus, TN, TC and BP(?) the sediments from the upper reaches of the Yellow River(1) Seven forms of P in sediments were investigated by using the improved seven-step sequential extraction method and distinguished (?) following:exchangeable+loosely bound P(Ex-P), aluminum-bound P(A1-P), iron-bound P(Fe-P), obstinate-bound P(Obs-P), anthigenic+biogenic apatite +calcium carbonate-bound P(Ca-P), Detrital apatite+other remaining inorganic P (De-P), organic P(OP). In all samples with different particle sizes from the upper reaches of the Yellow River, De-P and Ca-P were the major components and their contents ranged from 139.08 mg-kg-1 to 482.89 mg-kg-1 and from 40.30 mg-kg-1 to 125.55 mg-kg-1,respectively, both of them occupied about 86.72% of TP; OP contens ranged from 6.14 mg-kg-1 to 36.74 mg-kg-1 and was 3.90% of TP; the mean of Ex-P, Al-P and Fe-P was 7.53 mg·kg-1,25.85 mg-kg-1 and 5.05 mg-kg-1, respectively, all of there were about 9.23% of TP; Obs-P contents were the lowest in all form P, the average was 0.64 mg-kg-1, about 0.15% of TP; The maximum contents of Ex-P, Fe-P were appeared in sediments of Qinghai Maduo that is the source of the Yellow River, the maximum value of Ca-P, De-P were appeared at Qinghai Guide, the maximum contents of Al-P, Obs-P and OP were appeared in sediments of Inner Mongolia Baotou, Ningxia Zhongwei and Inner Mongolia Hekou, respectively.(2) The content distribution of various form P in studied sediments correlated with the grain size and the sampling sites directly. The relations between various form P of one kind of sediment and grain sizes and between one form P of different sediments and grain sizes were different, for example, the Ex-P contents in sediments of Zhongwei reduced with grain size minishing and in the other sediments were opposite. The positive correlation between the contents of De-P and TP was very remarkable, so De-P was the major contributor to TP.(3) The mean of TP.TC and TN was 1249.24 mg-kg-1,62.14 mg-kg-1 and 324.98 mg-kg-1, respectively. Their content distributions changed with the sampling sites. The maximum values of TC and TN all appeared in Maduo.(4) In all studied samples, the contents of potential bioavailable phosphorus (BP) were at least about 5.91%～30.17% of TP. Based on the quantity of paticulates transported from the Yellow River to the Bohai Sea and the above results, the amount of potential BP was estimated approximately 32.1～89.2 thousand ton.2 Adsorption charicterristics of P onto sediments from the upper reaches of the Yellow RiverP adsorption kinetics and its influence factors, adsorption isotherm behavior and adsorption/desorption EPC0 and the influence of pH on adsorption in surface sediments from the upper reaches of the Yellow River were researched and the results indicated that:(1) The research on P adsorption kinetics indicates that the adsorption of sediments to P in their overlying water had same tendency, it was faster in 0～8 h, gradually slower in 8～48 h and after 48 h was basically balanceable, but adsorption amount of P on various sediments were different. Time, the initi(?) P concentration, sediment concentration and PH in solution had direct impac(?) on P adsorption. At different initial P concentration, P adsorption kinetics on(?) different sediments all followed second-order adsorption kinetic model and Webber-Morris diffusion equation which second-order adsorption rate constants and diffusion rate constants obtained were in range of 10.99～229.29 g·mg-1·h-1 and 0.0003～0.0020 mg/(g·h1/2), respectively. The P adsorption process was controlled by the intra-particle diffusion.(2) Adsorption isotherms of sediments to P indicated that isotherms for P sorption were well fitted to linear equation and Freundlich equation, as well as Langmuir equation, not fitted to Temkim equation, but the change tendency of experiment data fitted by Temkim equation were well fitted index equation and the relativities were very remarkable. Different pH values had different impacts on P adsoption isotherms. When equilibrium quality concentrations were the same, the absorption amount of phosphate onto other sediments was biggest near neutral condition, and was descended in acid and alkaline conditions except Guide or Baotou.(3) The correlation between the adsorption amount of sediments to P and initial P concentration had good linear relationship when P concentration in the overlying water was very low. According to the linear equation, adsoption-desorption equilibrium concentrations(EPC0 value) of different sediments to P were found and ranged from 0.002 mg·L-1 to 0.013 mg·L-1, which were all higher than P concentrations in waters, so the sediments had the trend of releasing P to overlying waters.
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