Short Chain Chlorinated Paraffins In Soil,Sediments And Seawater From Intertidal Zone Of China's Shandong Peninsula:Distribution,Composition,Migration Pattern And Influence Factors

Because of its persistence,bioaccumulation,long distance migration ability,high toxicity which is the characteristics of persistent organic pollutants(POPs),short chain chlorinated paraffins(SCCPs)attracted much attention.In 2016,at the 12th meeting of the Stockholm convention POPs review committee,annex F of the convention adopted a draft about SCCPs on socio-economic benefit assessment.In 2017,at the eighth meeting of the parties to the Stockholm convention,SCCPs is included in annex A of the convention to eliminate its worldwide production and use.In this paper,the concentration,composition and migration rules of SCCPs in coastal land,intertidal zone and sea shore along the Shandong peninsula are studied.15 sampling sites along the Shandong peninsula are selected to collect samples in this study.As for samples collected along the Yellow sea coast of Shandong peninsula,the SCCPs concentration was 17.59-236.49 ng/g(dry weight,d.w.),and the average concentration was 72.59 ng/g(d.w.).Samples collected along the Bohai sea coast of Shandong peninsula,SCCPs concentration was 64.14-531.61 ng/g(d.w.),with an average concentration of 190.53 ng/g(d.w.).The concentration of SCCPs in the Bohai sea coast samples significantly higher than that of the Yellow sea coast.The mean values of SCCPs in the coastal soil,intertidal sediment and marine surface sediment from the sites along the coast of the Bohai sea were 120.31 ng/g,203.17 ng/g and 259.64 ng/g,respectively,representing that total SCCPs decreased with the distance from land to the ocean environment.In contrast,an opposite trend of SCCP spatial distribution was observed in the samples from the sites along the coast of the Yellow sea,with the mean values of SCCPs in land soil,intertidal sediment and marine surface sediment of 83.27 ng/g,70.17 ng/g and 64.32 ng/g,respectively.This phenomena may indicate that SCCPs pollution on the Bohai coast of Shandong peninsula mainly comes from the Bohai sea which polluted by the source from north and west shore,while the SCCPs pollution along the Yellow sea coast mainly comes from the coastal land areas,or affected by the monsoon.In terms of monomer composition,C10(the relative abundance of all samples are 20.25-61.34%)and Cl5,6(the relative abundance of all samples are 23.57-76.79%)are the main SCCPs homologue,and their overall performance shows the growth trend from land to sea.The reason for this may be that lightweight SCCPs are easier to migrate,and the fragmentation of chain and dechlorination reaction of SCCPs may occur in the process of the migration.As a reference,we collected seawater samples at the same 15 sampling sites.Through experimental analysis,the concentration of SCCPs in seawater samples of the Bohai sea was significantly higher than that in the Yellow sea seawater samples.This results in good agreement with the analysis results of soil and sediment samples,indicating that the SCCP pollution in the Bohai sea is worse than that of the the Yellow sea.Except a few sampling sites,the relative abundance of C10,11 homologue was over 50%,and the Cl5,6,7 homologue had a relative abundance over 50%.Two sediment cores were collected at Jimo(on the south shore of Shandong peninsula)and Laizhou(on the north shore of Shandong peninsula),respectively.The concentration of SCCPs is 59.29-193.97 ng/g in Jimo-core,and the concentration of SCCPs in Laizhou-core is 91.32-140.53 ng/g.But in general,the concentration of SCCPs in Laizhou-core is higher than that in Jimo-core.The concentration of SCCPs in every layer of two cores is relative high,indicating SCCPs are persistent.C10 and Cl5,6 homologue accounted for a large proportion in every sediment core layers,and with the increase of the sediment core depth,the relative abundance of the C10 and Cl5,6 homologue increased correspondingly.The content of chlorine in the two sediment cores is about 60%,and the chlorine content in Jimo-core is less than that in Laizhou-core.In this thesis,we investigated and analyzed the concentration,homologue,migration patterns and space-time distribution of SCCPs in the coastal area of Shandong peninsula.And this study further supplement the related data of SCCPs in the environment of China.