The Occurrence Form And Pollution Evaluation Of Phosphorus And Nitrogen In The Surface Sediments Of Changli Marine Ecological Monitoring Area

As an important source of ecological material circulation in the marine environment,nitrogen and phosphorus are hot issues in geochemical research.The content and distrtibution of nitrogen and phosphorus in surface sediment can affect the cycle process between sediment-water interfaces to varying degrees.Exploring the physicochemical properties of surface sediments;the occurrence forms,distribution characteristics and pollution degree of nitrogen and phosphorus elements can help to understand the ecological environment of coastal waters and maintain the ecological health of waters.In this paper,selecting 19 sampling sites of surface sediments in Changli marine ecological monitoring area as the object of study.The contents and distribution characteristics of nitrogen and phosphorus in sediment were analyzed specificly by continuous extraction method.The correlation between the number of phytoplankton cells,the physicochemical properties of sediments,and the different forms of nitrogen and phosphorus in the monitoring area were analyzed and discussed.Using sediment quality assessment formulated by Ontario Environmentand Energy and comprehensive pollution index method to analyze the pollution level of surface sediments in marine monitoring area.The main conclusions are as follows:(1)In the marine ecological monitoring area,the number of organic contents and phytoplankton cells decreased from south to north.The sediment type was dominated by sand.And the particle size near the coast is fine.(2)In the surface sediments of marine monitoring area,the range of TN content was from 98.00 to 1362.67 mg/kg,with an average content of 664.58 mg/kg,as a whole,the trend was decreased from south to north.The NTN was between 1.12 and 1190.06 mg/kg,which is the main form of TN.IEF-N content ranged from 8.30 to 82.11 mg/kg,the content of SAEF-N was 1.49-33.59 mg/kg,the content of SOEF-N was 7.10~54.35 mg/kg,the content of WAEF-N was 30.74-85.76 mg/kg.Land-sourced pollutant source input is the main reason for the high nitrogen content near the Luanhe River Estuary in the south.(3)In the surface sediments of marine monitoring area,the range of TP content was from 169.3 to 640.5 mg/kg,the average value of 309.54 mg/kg.IP is the main occurrence form of TP.The content of IP varied from 108.47 to 421.46 mg/kg,Ca-P was between 59.75 and 298.82 mg/kg,Fe/Al-P was between 28.78?128.35 mg/kg,and the content of OP ranged form 27.16 to 133.96 mg/kg.Among the 19 sampling points,the content of TP was the highest at point 5#and the lowest at point 16#.On the whole,the distribution trend was decreased from south to north(4)Correlation analysis showd that there was a significant correlation between organic matter and different forms of nitrogen and phosphorus.TN and TTN were significantly correlated with the number of phytoplankton cells.The SAEF-N and SOEF-N were significantly correlated with the number of medium diameter,TN was related with the number of medium diameter but not significant.TP,phytoplankton cell number and particle size were significantly correlated with phosphorus.There was a significant correlation between TN and TP,and both pollutants were similar(5)Sediment quality assessment formulated by Ontario Environmentand Energy and comprehensive pollution index method were applied to the paper,the Changli marine ecological monitoring area had a certain degree of nitrogen and phosphorus pollution Compared with other points,the 1#,5#points were at the level of severe pollution and had high degree of ecological toxicity.The marine ecological environment has a certain potential harm,it is necessary to take appropriate measures to prevent and control the eutrophication.