Spatial And Temporal Of Isstribution Of Polyhalogenated Carbazoles In Soils From Zhejiang Province

Polyhalogenated carbazoles(PHCZs)are one of the most important heterocyclic compounds containing nitrogen in the environment.They have some classical properties of persistent organic pollutants,such as long-distance transport,bioaccumulation,and ecotoxicities.PHCZs have been widely found in many environmental media,like sediment,soil,and atmosphere,as well as organisms.The present thesis studied the distribution of carbazole(CZ),3-bromo-9H-carbazole(3-BCZ),3-chloro-9H-carbazole(3-CCZ),3,6-dichloro-9H-carbazole(36-CCZ),1,3,6,8-tetrachloro-9H-carbazole(1368-CCZ),1-bromo-3,6-dichloro-9H-carbazole(1-B-36-CCZ),2,7-dibromo-9H-carbazole(27-BCZ),3,6-Dibromo-9H-carbazole(36-BCZ),1,8-Dibromo-3,6-dichloro-9H-carbazole(18-B-36-CCZ),1,3,6-tribromo-9H-carbazo(136-CZ),1,3,6,8-tetrabromo-9H-carbazole(1368-BCZ)and 2,3,6,7-tetrachloro-9H-carbazole(2367-CCZ)in 55 surface soil samples and 2column soil samples from Zhejiang Province.Moreover,possible resource of PHCZs in the aimed areas were also discussed.The main results are as follows:(1)The detection rates of carbazole and its halogenated compounds were probably higher than 80%,suggesting the universal existing of PHCZs in soils of Zhejiang Province.The average concentrations of 12 polyhalogenated carbazole in the surface soil in Zhejiang were: CZ,21.2 ± 2.8 ng/g dw(dry weight);3-CCZ,7.9 ± 3.2ng/g dw;3-BCZ,6.7 ± 2.5 ng/g dw;3,6-CCZ,57.7 ± 21.2 ng/g dw;1,3,6,8,-CCZ,0.9± 0.1 ng/g dw;1-B-3,6-CCZ,9.6± 3.5 ng/g dw;2,7-BCZ,9.0 ± 2.1 ng/g dw;3,6-BCZ,3.0 ± 2.1 ng/g dw;1,8-B-3,6-CCZ,15.1 ± 5.1 ng/g dw;1,3,6-BCZ,2.8 ± 1.8 ng/g dw;1,3,6,8-BCZ,20.2 ± 10.2 ng/g dw;2,3,6,7-CCZ,2.7 ± 1.4 ng/g dw.Compared withrelative data from foreign countries,PHCZs analyzed in this study were at a moderate level globally.Among all halogenated carbazole homologues,the amount of 36-CCZ is abundant,it may be related to its wider industrial origin and its special structure.(2)The concentration of PHCZs were higher in central and inland regions than in the periphery and coastal areas.The highest concentrations of PHCZs were obtained in D7(316 ng/g dry weight),which close a Jinhua Yongkang Industrial Park and in F7(299 ng/g dry weight),which near Taizhou e-waste dismantling area.The principal component analysis and correlation analysis showed that the distribution patterns of1368-BCZ and 18-B-36-CCZ were similar to those of traditional organochlorine pesticides,which indicates its industrial sources,while 3-CCZ,3-BCZ,and 36-CCZ are more likely to be natural sources..(3)PHCZs in the two soil columns vaired from 18.3 ng/g dw-379.5 ng/g dw,averagely 143.9 ng/g dw.36-CCZ is most abundant among the targeted analytes,with an average ratio of 66.5% and 29.7%,respectively for Cixi and Manxun column.This phenomenon is consistent with those found in surface soils from Zhejiang Province.The results of spatial distribution show that CZ,3-CCZ,3-BCZ and 36-CCZ have similar sources and tend to natural synthesis.1368-BCZ and 18-B-36-CCZ have similar sources and are biased towards industrial sources.Based on annual average sedimentation rate of 0.92 cm/year in the Yangtze River Delta,PHCZs in Nanxun column and Cixi column reached the maximum in 2007 and 1997,respectively.