长江口平原农田土壤中卤代咔唑的分布特征及毒性效应

Distribution Characteristics and Toxic Effects of Polyhalogenated Carbazoles in Agricultural Soils of the Yangtze River Estuary Plains

卤代咔唑(polyhalogenated carbazoles,PHCZs)是一种与多氯二苯并呋喃(polychlorinated dibenzofuran,PCDFs)结构相似的新污染物,具有类二噁英毒性、环境持久性和生物累积性。采用气相色谱-质谱联用仪分析了江苏省太仓地区长江口平原农田土壤中卤代咔唑的污染状况。结果表明,总卤代咔唑(ΣPHCZs)浓度范围为20.7~76.2 ng·g^(-1)(以干质量计,下同)(中值为37.17 ng·g^(-1)),咔唑(CZ)的浓度范围为1.98~155.07 ng·g^(-1)(中值为4.13 ng·g^(-1))。土壤中PHCZs的分布特征受太仓地区家庭零散种植农业模式的影响,呈空间无序性。同系物中同分异构体浓度呈显著正相关,而PHCZs各组分与总有机碳(TOC)之间相关性不显著。长江口平原农田土壤中PHCZs毒性当量(TEQ PHCZs)范围为2.80~7.98 pg TEQ·g^(-1)(均值为4.73 pg TEQ·g^(-1)),低于沉积物的安全TEQ值(20 pg TEQ·g^(-1)),毒性效应较低。

Polyhalogenated carbazoles(PHCZs)are contaminants of emerging concern with a similar structure to polychlorinated dibenzofuran(PCDFs),and exhibit dioxin-like toxicity,environmental persistence and bioaccumulation.In this study,gas chromatography-mass spectrometry(GC-MS)was used to analyze the contamination status of PHCZs in farmland soil in the Yangtze Estuary Plain in Taicang,Jiangsu Province.The results revealed that the concentration of total PHCZs(ΣPHCZs)ranged from 20.7 to 76.2 ng·g^(-1)(calculated on dry mass;the same below)(median 37.17 ng·g^(-1)),and the concentration of carbazole(CZ)was varied from 1.98 to 155.07 ng·g^(-1)(median 4.13 ng·g^(-1)).The distribution characteristics of PHCZs in soil were spatially disordered and influenced by the scattered farming model of households in Taicang area.And there was a significant positive correlation between the i somer concentrations of PHCZs homologues,while the correlation between each component of PHCZs and total organic carbon(TOC)is not significant.The toxic equivalent(TEQ PHCZs)of PHCZs in farmland soil in the Yangtze River Estuary Plain ranges from 2.80 to 7.98 pg TEQ·g^(-1)(mean 4.73 pg TEQ·g^(-1)),which is lower than the safe TEQ value of sediment(20 pg TEQ·g^(-1)),indicating low toxic effect.