Interannual Evolution And Ecological Risk Of PAHs In Columnar Sediments Of Changxing Island

Polycyclic aromatic hydrocarbons?PAHs?are a class of organic pollutants that are widely found in the environment.The content in various media of nature is not high but extremely dangerous.The harm to living organisms,human body and even natural ecosystems cannot be ignored,and thus has become the focus of attention.The Changxing Island Near-port Industrial Zone plays an important role in the development of the coastal economy of Liaoning Province,and the problems of shore line resource development and environmental pollution have become increasingly serious.Pollutant emissions have changed the living environment of the organisms,and also increased the pollution of the surrounding water bodies and sediments.The environmental problems brought about by economic development cannot be ignored.In the past,there have been relatively few studies on persistent organic matter in columnar sediments,especially in areas where offshore industries have been developed after land reclaration.In this paper,based on the survey data of three columnar stations?C4,C6 and C8?in the coastal sedimentary and sedimentary chemistry of Changxing Island in 201 7,the interannual evolution and organic pollution of PAHs in borehole core samples were studied.The main source of PAHs in this area was analyzed by the ratio method.By conparing the standard values,the ecological risks that PAHs may cause to the sea area are analyzed.This will provide support for environmental pollution research,corrPrehensive evaluation,carrying capacity forecast and warning,and serve as a basis for the feasi'oility of development,utilization and pollution control To this end,the author conducted the following five aspects by the analysis of the experimental results.?1?The average sedimentation rate of sediments in Changxing Island is estimated to be 0.579 cm·a-1 by 2210Pb method.The vertical distribution of PAHs in the sediment core of the sea area is obtained by combining the results of year and concentration determination.The PAHs content changed relatively little before the 1980s.With the increase of the age,the overall trend is obviously rising.With the changes of the surrounding environment,there are obvious fluctuations,which are basically consistent with the industrialization growth of the island.?2?In terms of pollution characteristics,the concentration of ?P AHs in the three sedimentary columns?C4,C6 and C8?ranged from 32.76 to 289.49 ng·g^-1,22.16 to 81.34 ng·g^-1 and 20.19 to 74.24 ng·g^-1;mean values were 96.30 ng·g^-1,41.40 ng·g^-1 and 44.52 ng·g^-1?both dry weight?.In terms of composition classification,the monomer with the highest content in the sea area was Phe.On the ring number classification,the results of three rings>four rings>two rings>five rings>six rings were presented.?3?The distribution of PAHs in the region was controlled by sedimentary type and hydrodynamic factors.On the sedimentary type,the sea area presents a coarse-to-fine sediment zoning pattern from the top of the bay to the shallow sea along along the coast line.The smaller the particle size,the stronger the adsorption of pollutants in water,and the higher the PAHs content.In terms of hydrodynamics,the fluctuation trend of the main axis of the sea area was basically the same as that of the navigation channel.The C6 and C8 stations were dominated by the tidal currents in the bay,while the C4 station was co-administered by the tides in the offshore and the bay,it had higher sediment transport than C6 and C8,and it was easier to input pollutants into the sediments.Therefore,in the horizontal direction,the content distribution of ?P AHs generally shows the result ofC4>C8>C6.?4?Using the ratio method to analyze the sources of PAHs in the columnar sediments of Hulushan Bay,Changxing Island.It appeared to be mainly a mixed source of petroleum sources and liquid fossil fuels and biomass fuel combustion.And as time goes on,there is a tendency to contribute more to the combustion source.?5?A comparative analysis of the potential ecological risks of PAHs in columnar sediments in the Changxing Island using a variety of standard indicators.On the whole,it shows a low toxic effect on ecosystems and organisms.And with the rapid development of regional industrial development,it may continue to increase,and needs to be taken seriously.