Peng Lu, Liu Lili, Li Peng, Lin Kunde
Fujian Provincial Key Laboratory for Coast Ecology and Environmental Studies, College of the Environment and Ecology, Xiamen University, Xiamen, 361102, China.
State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, East China University of Science and Technology, Shanghai, 200237, China.
Environ Pollut. 2023 Feb 15;319:120957. doi: 10.1016/j.envpol.2022.120957. Epub 2022 Dec 31.
Polyhalogenated carbazoles (PHCZs) have been increasingly detected in marine sediment, raising concerns in recent years. In this study, sediment samples (42 surface and one core) were collected from the Yangtze River estuary and the adjacent East China Sea, and eleven PHCZs and unsubstituted carbazole were measured. The total concentration of PHCZs in surface sediments ranged from 0.19 to 2.49 ng/g dry weight (d.w.) (median 1.03 ng/g d. w.). The congener compositions of PHCZs in the surface sediment were dominated by 3,6-dichlorocarbazole (36-CCZ, 53.2%), followed by 3-chlorocarbazole (14.9%) and 3,6-dibromocarbazole (36-BCZ, 11.8%). Carbazole in the surface sediment ranged from not detected to 9.89 ng/g (median 1.25 ng/g), with a detection frequency of 81.0%. The spatial distribution of 36-CCZ in surface sediments exhibited a clear decline from the coast to offshore, while 36-BCZ showed the opposite trend. The depth profile of 36-CCZ was maintained at a relatively low and stable concentration (about 0.36 ng/g) in core segments from 1903 to 1951, followed by a steady increase to 1.5 ng/g in 2006. This increase coincides with the industrial and agricultural development in China that began in the 1950s. In contrast, the other detected PHCZs and carbazole maintained stable, low concentrations over time. These spatial and temporal patterns suggest that 36-CCZ in this area is predominantly from anthropogenic sources, while 36-BCZ has a natural origin. Toxic equivalent estimations indicated that dioxin-like effects for the observed PHCZs were low. These results provide useful information for understanding the origin of PHCZs and carbazole in this area.
多卤代咔唑（PHCZs）近年来在海洋沉积物中被越来越多地检测到，引发了人们的关注。在本研究中，从长江口及邻近的东海采集了沉积物样本（42个表层样本和1个柱状样本），并测定了11种多卤代咔唑和未取代的咔唑。表层沉积物中多卤代咔唑的总浓度范围为0.19至2.49纳克/克干重（中位数为1.03纳克/克干重）。表层沉积物中多卤代咔唑的同系物组成以3,6 - 二氯咔唑（36 - CCZ，53.2%）为主，其次是3 - 氯咔唑（14.9%）和3,6 - 二溴咔唑（36 - BCZ，11.8%）。表层沉积物中的咔唑含量范围为未检测到至9.89纳克/克（中位数为1.25纳克/克），检测频率为81.0%。表层沉积物中36 - CCZ的空间分布呈现出从海岸到近海明显下降的趋势，而36 - BCZ则呈现相反的趋势。在1903年至1951年的柱状样本段中，36 - CCZ的深度剖面保持在相对较低且稳定的浓度（约0.36纳克/克），随后在2006年稳步增加至1.5纳克/克。这种增加与中国始于20世纪50年代的工农业发展相吻合。相比之下，其他检测到的多卤代咔唑和咔唑随时间保持稳定的低浓度。这些时空模式表明，该区域的36 - CCZ主要来自人为源，而36 - BCZ具有天然来源。毒性当量估计表明，所观察到的多卤代咔唑的二噁英样效应较低。这些结果为了解该区域多卤代咔唑和咔唑的来源提供了有用信息。
