Distribution Characteristics And Transformation Of Nutrients In Surface Sediments Of Jinpen Reservoir

In order to understand the distribution characteristics and transformation of nutrients in surface sediments and the effect of water lifting aerator on control of sediment pollution released from Jinpen Reservoir.The physical and chemical properties of the overlying water and surface sediments(temperature,dissolved oxygen,pH,water depth,water content,particle size),surface sediment nutrients(nitrogen,phosphorus forms,organic matter)were monitored in a whole year.The results showed that:(1)the distribution characteristics of nutrients in surface sediments of Jinpen Reservoir;(2)the distribution of phosphorus forms and the variation of four seasons;(3)the pollution evaluation and source of nutrients;(4)the migration of phosphorus;(5)Study on application of water-lifting aeration.The main conclusions are as follows:(1)The temperature of the overlying water in Jinpen Reservoir was between 6.15~13.35?,the pH was slightly acidic in summer and alkaline in other seasons,the seasonal variation of DO siginificantly changed from 0.48 to 9.73mg/L and the lowest DO in summer was 0 mg/L;overlying water and pore water have the highest phosphate Concentration in summer.High water content,indicated that the water is easily suspended under the disturbance.The change of average grain size is not significant,but the overall grain size is fine,indicated that the hydrodynamic force is weak.(2)The results showed that the contents of TN was 424~1460 mg/kg?and the average contents of OM was 7.02%.All reservoir,with the same spatial distribution,from upstream to the reservoir area,the contents Increased at first and decreased afterwards.Compared with other lakes and reservoirs,the contents of TN in surface sediments were relatively small,but the contents of TP and OM were in the middle level in Jinpen reservoir.Jinpen reservoir had been polluted to some extent.(3)Total phosphorus(TP)content in sediments ranged from 987~1326 mg/kg,from upstream storage to reservoir area,and the total phosphorus content increases.Meanwhile,inorganic phosphorus(IP)was the main component in sediment and accounted for 62.5%~78.9% of the total phosphorus(TP),and Ca-P accounted for 46.5%~71.4% of TP.Variation trends of IP and TP was basically the same,and the change of TP is primarily determined by IP,but IP content was regulated by Ca-P and Fe/Al-P.(4)The content of TP was the highest in winter and the lowest in summer.The content of OP in winter was significantly higher than that in other seasons,the content of Al/Fe-P in winter was the lowest in winter,and Ca-P did not changed with the seasons.The contents of phosphorus in each season were Ca-P> OP> Al/Fe-P.(5)The contents of TN,TP and OM in all sampling points of Jinpen Reservoir ware at the lowest level,and it had ecological toxicity and was potentially harmful to the environment and animals.The range of TOC/TN is 30.0~58.3,which indicateed that OM of the surface sediments of Jinpen Reservoir is derived from higher terrestrial plants.OM,TN and TP have a mutual connection,the correlation between OM and TN was higher,which indicated that the mineralization process of organic matter in surface sediments of Jinpen Reservoir was related to the source of nitrogen and phosphorus,especially more closely related to nitrogen and the deposition process.(6)The forms of phosphorus(TP and OP),TN and organic matter contents in the surface sediments of the monitoring sites showed a gradual decrease process during the operation of the aeration system.Al/Fe-P had a small increase during operation,and the effect of aerator operation on Ca-P content was not obvious.The operation of water-lifting aeration improved the overall metabolic activity of microbes in surface sediments and its utilization to carbon sources.