Polyhalogenated carbazoles in sediments from the intertidal zone of the New River Estuary, China: Distribution, inventory, and ecological risks

Abstract Polyhalogenated carbazole (PHCZ), a class of emerging organic pollutants, is rarely detected in wetlands. Herein, for the first time, carbazole and seven PHCZ congeners were detected in sediments from the intertidal zone of the New River Estuary, Beidaihe Wetlands, Northern China. The total PHCZs ranged from 2.42 to 61.15 ng/g dw (median: 3.82 ng/g dw) in the sediments, with 3-bromocarbazole and 3,6-dibromocarbazole as the main components. The toxic equivalent (TEQ) evaluation of PHCZs showed that the TEQs (0.08–1.58 pg TEQ/g dw) in the sampling sites were lower than the safe sediment TEQ value (20 pg TEQ/g dw). The estimated inventories of PHCZs ranged from 0 to 279.23 kg, with a total amount of 902.28 kg, which is much higher than that in other regions of China. The higher inventories in this famous tourist sanctuary suggest that attention should be paid to their environmental occurrence, distribution, origin, behavior, and risk.