title: The fingerprints of dioxin-like bromocarbazoles and chlorocarbazoles in selected forest soils in Germany.
abstract: 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. Concentrations ranged from 0.6 to 267.6 ng/g (carbazole); 0.2-7.2 ng/g (3-bromocarbazole); 0.0-9.1 ng/g (3-chlorocarbazole); 0.2-19.8 ng/g (3,6-dibromocarbazole); 0.4-67.6 ng/g (3,6-dichlorocarbazole); 0.0-0.7 ng/g (PCDDs); 0.0-0.3 ng/g (PCDFs) and 0.0-33.7 ng/g (PCBs). Concentrations decreased with depth and correlated positively to total organic carbon (TOC). When it was based on TOC%, an increase in concentration with depth was observed in most soil samples. With respect to dioxin-like toxicity, 3-bromocarbazole, 3-chlorocarbazole, 3,6-dibromocarbazole and 3,6-dichlorocarbazoles caused induction of CYP1A1-dependent EROD activity in HII4E rat hepatoma cell line. Their relative effect potency after 72 h exposure ranged from 0.00005 to 0.00013 and was directly related to the degree of halogenation with 2,3,7,8-tetrachlorodibenzo-p-dioxin as reference. Furthermore, their contribution to overall soil dioxin-like toxicity was not significant in comparison to PCDD/Fs and PCBs though the sum toxic equivalency was limited to three halogenated carbazole congeners. Bromocarbazoles and chlorocarbazoles are emerging dioxin-like toxic environmental contaminants with potential for wide distribution occurring simultaneously with PCDD/Fs and PCBs.
authors.affiliation: Helmholtz Zentrum München-German Research Center for Environmental Health (GmbH), Molecular EXposomics (MEX), Ingolstädter Landstraße 1, 85764 Neuherberg, Germany; Department of Biosciences, Technical University of Munich, Weihenstephaner Steig 23, 85350 Freising, Germany; National Environment Management Authority, P.O. Box 67839-00200, Nairobi, Kenya. Electronic address: john.mumbo@helmholtz-muenchen.de.
authors.forename: John
authors.initials: J
authors.lastname: Mumbo
authors.affiliation: Helmholtz Zentrum München-German Research Center for Environmental Health (GmbH), Molecular EXposomics (MEX), Ingolstädter Landstraße 1, 85764 Neuherberg, Germany.
authors.forename: Marchela
authors.initials: M
authors.lastname: Pandelova
authors.affiliation: Helmholtz Zentrum München-German Research Center for Environmental Health (GmbH), Molecular EXposomics (MEX), Ingolstädter Landstraße 1, 85764 Neuherberg, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Mertes
authors.affiliation: Helmholtz Zentrum München-German Research Center for Environmental Health (GmbH), Molecular EXposomics (MEX), Ingolstädter Landstraße 1, 85764 Neuherberg, Germany.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Henkelmann
authors.affiliation: Federal Environment Agency, Section Soil Quality and Soil Monitoring, Wörlitzer Platz 1, 06844 Dessau-Roßlau, Germany.
authors.forename: Bernd M
authors.initials: BM
authors.lastname: Bussian
authors.affiliation: Helmholtz Zentrum München-German Research Center for Environmental Health (GmbH), Molecular EXposomics (MEX), Ingolstädter Landstraße 1, 85764 Neuherberg, Germany; Department of Biosciences, Technical University of Munich, Weihenstephaner Steig 23, 85350 Freising, Germany.
authors.forename: Karl-Werner
authors.initials: KW
authors.lastname: Schramm
mesh_terms: D000818:Animals; D001572:Benzofurans / Q000032:analysis; D002227:Carbazoles / Q000032:analysis* / Q000737:chemistry; D019363:Cytochrome P-450 CYP1A1 / Q000378:metabolism; D004147:Dioxins / Q000032:analysis* / Q000737:chemistry; D004784:Environmental Monitoring / Q000379:methods*; D004787:Environmental Pollution / Q000032:analysis; D065928:Forests; D005858:Germany; D054879:Halogenation; D011078:Polychlorinated Biphenyls / Q000032:analysis; D000072317:Polychlorinated Dibenzodioxins; D051381:Rats; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis*
chemical_list: C558653:3,6-dichlorocarbazole; D001572:Benzofurans; D002227:Carbazoles; D004147:Dioxins; D000072317:Polychlorinated Dibenzodioxins; D012987:Soil; D012989:Soil Pollutants; D011078:Polychlorinated Biphenyls; C569463:CYP1A1 protein, human; D019363:Cytochrome P-450 CYP1A1; C558654:3-chlorocarbazole
keywords: Bromocarbazole and chlorocarbazole; Dioxin-like toxicity; Forest soil; Occurrence; Relative effect potency; Toxic equivalent