Distribution Characteristics Of Petroleum Hydrocarbons In Sediments Of Liaohe Estuary Wetland And Their Relationship With Physicochemical Properties

As a land-sea transition zone,wetlands have an irreplaceable role in other ecosystems in regulating climate,purifying water,conserving water sources,conserving biodiversity,and maintaining ecological balance in nature.This paper takes Liaohe Estuary Wetland as the research object,analyzes petroleum hydrocarbons,total nitrogen,total phosphorus,organic matter,p H and conductivity in sediments by using fixed-point sampling and statistical and mathematical models to explore the difference of petroleum hydrocarbon content in different functional areas of wetland.With the law of spatial distribution,understand the basic conditions of the physical properties of wetland sediments and explore its intrinsic relationship with petroleum hydrocarbons.Therefore,it provides a scientific and reliable theoretical basis for the rational development and utilization of wetlands.Analysis shows:In the wetland functional area,the difference between the petroleum hydrocarbon content and the buffer zone in the experimental area is not significant,and the difference between the core area and the experimental area and the buffer zone is significant.The petroleum hydrocarbon content is generally in the buffer zone>experimental zone>core zone.And the petroleum hydrocarbon content of sediments at all points is less than the critical value of soil petroleum content of 500mg·kg^-1,indicating that the wetland petroleum hydrocarbon pollution is lighter.Longitudinal distribution:In areas with large disturbances,the petroleum hydrocarbon content of sediments generally ranges from the surface layer to the bottom layer,and its content gradually decreases with increasing depth.The petroleum hydrocarbons are enriched in sediments of 0-20 cm and the content is significantly higher than that of 20-50 cm petroleum hydrocarbons,and the difference is significant.In the less disturbed area,the petroleum hydrocarbon content is generally 0-40cm from the sediment,and its content gradually increases with the increase of depth.The petroleum hydrocarbon content in the sediment below 40cm decreases significantly,and the maximum content appears in the sediment 30-40cm and Significantly different from the other layers,this is due to the long-term infiltration of petroleum hydrocarbons.The purification of petroleum hydrocarbons by rheological microorganisms such as petroleum hydrocarbon volatilization,photolysis and reed causes the petroleum hydrocarbon content to be higher in spring?May?than in summer?July?,mainly in the experimental area,buffer zone and core area.In the core area,near the Liaohekou and Bohai Sea areas,the petroleum hydrocarbon content is slightly higher in the summer?July?than in the spring?May?due to runoff from rivers and seawater.Lateral distribution:There are differences in petroleum hydrocarbon content in the sediments of the wetland and the near river.In the Yuanhe area,the oil hydrocarbon content buffer in the sediment of 0-10cm is higher,and the content of 10-20cm fluctuates,showing an"M"shape and a high content of 30-50cm core area.In the near river area,the 0-20 cm petroleum hydrocarbon content buffer of the sediment is higher than the experimental area and the core area,and the fluctuation of 30-50 cm content has no obvious law.The intrinsic relationship between petroleum hydrocarbons and sedimentation physical properties is as follows:there is a significant correlation between organic matter content and petroleum hydrocarbon content?P<0.01?.The entry of petroleum hydrocarbon pollutants into sediments will increase the content of organic matter;the total nitrogen content will follow The increase of petroleum hydrocarbon content decreased,but the difference was not significant?P>0.05?;the difference of total phosphorus content and petroleum hydrocarbon content was significant,showing a significant correlation?P<0.05?,with petroleum hydrocarbon content.The increase of total phosphorus content will decrease,and the pollution of petroleum hydrocarbons in sediments will lead to the imbalance of nitrogen and phosphorus.In the process of degrading petroleum hydrocarbons,microorganisms also need to consume nutrients such as nitrogen and phosphorus to break the original nutritional balance.Therefore,when repairing petroleum hydrocarbon pollution,certain nitrogen and phosphorus elements can be added to enhance the activity of microorganisms and accelerate the decomposition of petroleum hydrocarbon pollutants;p H,conductivity and petroleum hydrocarbon content are positively correlated,and there is a significant correlation.?P<0.05?;Petroleum hydrocarbon pollution has changed the nature of sediments to some extent and has a certain negative impact on sediment quality.