Study On The Existing Form And The Loss Of Rock Phosphorus In Eastern Section Of The North Shore Of Chaohu Lake Area

Chaohu is located in the geological phosphorus-rich area. It can’t be ignoredthat the natural weathering of the surrounding rocks and artificial developmentwhich it lead to the migration of phosphorus and the lake eutrophication.The existing form of three weathering degree rocks in the Chaohu area wereinvestigated by sequential extraction method. The results show that: with theweathering process, the total phosphorus content decreased in the six groups ofrocks; In most groups’, the content of Ex-P、Al-P、De-P、Oc-P and Ca-P show adownward trend while the content of Fe-P and Or-P show a upward trend. The mainexisting form of phosphorus is the Oc-P. The pH value of the rock is an importantfactor which impact the existing form of phosphorous t hrough compared thecontent and the distribution of phosphorous with the pH value. Therefore, theweathering of the rock is one of the important factors of water eutrophication ofChaohu Lake Basin.In order to investigate the impact of the soil background phosphorus in theaquatic environment, the experiment analyses the disposition and the loss risk ofsoil phosphorus by assaying phosphorus environmental behavioral parameters ofsoil. The result show that:soil phosphorus content of the background distributionobtained higher phosphorus content in the Chaohu area. The phosphorusenvironmental behavior parameters which include the concentration level of totalphosphorus, available phosphorus, soluble phosphorus （RDP） and algae availablephosphorus （BAP） are high. The values of phosphorus sorption index （SI） and thephosphorus sorption saturation （DPSS） is low which represent the phosphorusadsorbent capacity of soil and the phosphorus retention capacity of soil, thus thesoil phosphorus can easily be lost with the runoff and other means in the Chaohuarea.At the same time, using the rock of Gufeng group which is the represent rockof the phosphorus-rich area of Chaohu, We design the simulative leaching experiment of soil column. The results show that: low molecular weight organicacid can promote the release of phosphorus and the release of phosphorus isstimulated with the extension of the leaching cycle; When concentrations of organicacid is less than5mmol L^-1,the order of phosphorus release ability is tartaric acid> oxalic acid> citrate acid and the tartaric acid’s release ability of phosphorus islarger than others; When concentrations of organic acid is10mmol L^-1, the changeof phosphorous release size of low molecular weight organic acid is more gentleand the order of phosphorus release ability is oxalic acid> tartaric acid> citrateacid and the oxalic acid’s release ability of phosphorus is larger than others; Whenconcentrations of organic acid is50mmol L^-1, the amount of phosphorus release ishigher than the low concentration gradient of organic acids and the order ofphosphorus release ability is tartaric acid> oxalic acid> citrate acid. Thesimulative acid rain also can promote the release of phosphorus.