Photodegradative fate and potential phototoxic products of bromocarbazoles and chlorocarbazoles in water.

Bromocarbazoles and chlorocarbazoles are emerging environmental contaminants that have been reported to be persistent and possessing dioxin-like toxicity; however, their photodegradative fate in water is unknown. The photodegradation of 3-bromocarbazole, 3-chlorocarbazole, and 3,6-dichlorocarbazole was determined in ultrapure water. They proceeded by direct photolysis and followed first-order kinetics.

Comparative study of dioxin contamination from forest soil samples (BZE II) by mass spectrometry and EROD bioassay.

Dioxins and dioxin-like compounds can be analyzed by bioanalytical screening methods to evaluate their biotoxicity. In vitro bioassays, based on 7-ethoxyresorufin-O-deethylase (EROD) and the activity of cytochrome P450 1A1 and the aryl hydrogen receptor (AhR) pathway, are employed for the evaluation of bioanalytical equivalents (BEQ) of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) from a wide variety of sample matrices. Here, we present the evaluation of 11 humic soil samples derived from forest stands across Germany and a comparison of the BEQ values against toxic equivalents (TEQ, PCDD/Fs+PCBs) derived by chemical analysis.

The fingerprints of dioxin-like bromocarbazoles and chlorocarbazoles in selected forest soils in Germany.

The occurrence of bromocarbazoles and chlorocarbazoles was studied in 86 forest soil samples from different regions in Germany. Carbazole, 3-chlorocarbazole, 3-bromocarbazole and 3,6-dibromocarbazole were qualitatively detected in the humic layer of 59 soil samples with bromocarbazoles reported here for the first time in soil. Furthermore, the halogenated carbazoles, PCDD/Fs and PCBs were detected in the humic and mineral soil horizons (0-5 cm and 5-10 cm) of a subset of 11 soil samples subjected to quantitative analysis.

Persistence and dioxin-like toxicity of carbazole and chlorocarbazoles in soil.

Halogenated carbazoles have recently been detected in soil and water samples, but their environmental effects and fate are unknown. Eighty-four soil samples obtained from a site with no recorded history of pollution were used to assess the persistence and dioxin-like toxicity of carbazole and chlorocarbazoles in soil under controlled conditions for 15 months. Soil samples were divided into two temperature conditions, 15 and 20 °C, both under fluctuating soil moisture conditions comprising 19 and 44 drying-rewetting cycles, respectively.

Enzymatic synthesis of bromo- and chlorocarbazoles and elucidation of their structures by molecular modeling.

3-Chlorocarbazole, 3,6-dichlorocarbazole, dibromocarbazole, and 1,3,6,8-tetrabromocarbazole are emerging environmental contaminants which have been detected recently in water, sediment, and soil samples. However, their sources and occurrence have not been explained. Here, we report an enzymatic synthesis of bromo- and chlorocarbazoles by chloroperoxidase from Caldariomyces fumago in water.