| The inflow of river sediments into the sea is an effective carrier for studying the pollution status around the land.In this paper,32 sediments sample from 9 river in Haizhou Bay into the sea are taken as the research object,and the black carbon(abbreviated as BC,including char and soot),magnetic susceptibility(MS),total organic carbon(TOC),polycyclic aromatic hydrocarbons(PAHs)and heavy metal elements(abbreviated as HMs,including elements such as Mn,Cr,Ni,Zn and Pb)are tested and analyzed.Systematically explore the geochemical characteristics and correlations of various indicators in the sediments of Haizhou Bay.Using Arcgis and SPSS analysis,the assessment and source analysis of black carbon,polycyclic aromatic hydrocarbons and heavy metals were carried out.The results of the study provided basic data for the in-depth understanding of the pollution status of the study area and the countermeasures.The main findings are as follows:(1)The spatial distribution of the concentrations of different geochemical indicators in the sediments of the Haizhou Bay into the sea is significantly regional.The concentration of black carbon ranges from 0.144 to 4.678 mg/g,and the average value is 1.005 mg/g.The highest value is in the Shiliang River Basin sample southwest of the region SLH-4(4.678 mg/g),and the lowest value appears in the embroidered river basin sample XZ-2(0.079 mg/g)in the northeastern part of the region.The concentration of total organic carbon varied from 0.083 to 2.290 mg/g with an average of 0.726 mg/g.The highest value was in the Shawang River Basin sample SWH-1(2.290 mg/g)in the middle of the region,and the lowest value appears in the embroidery needle river area sample XZ-2(0.083 mg/g)in the northeastern part of the region;The concentrations of five heavy metals varied in Cr(47.88~135.44 mg/kg),Mn(268.11~2050.52 mg/kg),Ni(17.68~133.05 mg/kg),and Zn(30.42~605.11 mg/kg).),Pb(18.13~71 mg/kg)changes.All average concentrations were higher than their environmental background values(the environmental background values of the five heavy metals were Cr(60.28 mg/kg),Mn(570 mg/kg),Ni(31.62 mg/kg),Zn(64.68 mg/kg)and Pb(24.7 mg/kg),respectively).The spatial distribution(Cr,Mn,Ni,Zn,Pb)is reduced by the northeastern embroidered needles and other rivers along the Haizhou Bay coast to the southwestern Shiliang River Basin;The total concentration and average concentration of 16 polycyclic aromatic hydrocarbons were 456.85~3048.86 ng/g and 1237.36 ng/g,respectively;the components were mainly composed of 3~5 rings.From the spatial distribution of polycyclic aromatics concentration,the concentration of polycyclic aromatic hydrocarbons in the Linhong River Basin in the southwestern part of the area is the highest.It can be seen that the regional distribution of the concentration distribution of various environmental indicators in the sediments of the Haizhou Bay into the sea is closely related to the urban and rural industrial spatial pattern and the intensity of human activities in Haizhou Bay.(2)According to the three methods of evaluation of the cumulative index method,the potential risk index method and the enrichment factor,heavy metal Mn,Cr,Ni,Zn and Pb pollution are light and moderate pollution;From the BC/TOC value(0.5~1),the black carbon in the sediments of the Haizhou Bay into the sea is mainly from the biomass burning of regional fossil fuels and seaport traffic;The isomeric ratio indicates that polycyclic aromatic hydrocarbons in the sediments of the Haizhou Bay into the sea are mainly derived from coal,oil and biomass burning.It can be seen that heavy metals,black carbon and polycyclic aromatic hydrocarbons in the sediments of the Haizhou Bay into the sea indicate that the pollutants in this area are mainly derived from the petrochemical industry and seaport traffic operations around the Haizhou Bay area.Emission of pollutants.(3)The differences in the correlations between black carbon total organic carbon,heavy metals and polycyclic aromatic hydrocarbons in sediments from different rivers are closely related to their different sources.The correlations between black carbon,heavy metals,total organic carbon and polycyclic aromatic hydrocarbons in sediments indicate that the pollutants in the sediments of the Haizhou Bay into the sea are from mixed sources.black carbon and total organic carbon,polycyclic aromatic hydrocarbons are mainly derived from the combustion source of biomass or fossil fuels.Heavy metals are mainly derived from plant pollutant emissions.The correlation between black carbon and polycyclic aromatic hydrocarbons was significant(P<0.05)relative to total organic carbon,and Char was significantly positively correlated with 3 rings(P<0.01),which was related to human agricultural biomass combustion;Soot and 4 rings Positive correlation(P<0.05),related to pollutant emissions from surrounding petrochemical industries and seaport traffic operations;The correlation between the black carbon component Soot and heavy metals is significantly higher than that of Char and heavy metals.The enrichment of heavy metals by black carbon indicates that black carbon can be an ideal precursor for polycyclic aromatic hydrocarbons and heavy metals,and it has important indication significance for the degree of pollution.In summary,the differences in sources of heavy metals,black carbon,and polycyclic aromatic hydrocarbons in sediments are not only related to the combustion process of human active emissions,but also to the mobilization of regional emissions and sedimentary burial.Controlled by the school.Figure 19,table 16,and reference 107. |
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