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: John Mumbo, Marchela Pandelova, Florian Mertes, Bernhard Henkelmann, Bernd M Bussian, Karl-Werner Schramm
• Journal: Chemosphere (Chemosphere) Vol. 162 Pg. 64-72 (Nov 2016) ISSN: 1879-1298 [Electronic] England
• PMID: 27479457 (Publication Type: Journal Article)
• Copyright: Copyright © 2016 Elsevier Ltd. All rights reserved.

Chemical References

• 3,6-dichlorocarbazole
• Benzofurans
• Carbazoles
• Dioxins
• Polychlorinated Dibenzodioxins
• Soil
• Soil Pollutants
• Polychlorinated Biphenyls
• CYP1A1 protein, human
• Cytochrome P-450 CYP1A1
• 3-chlorocarbazole

Topics

• Animals
• Benzofurans (analysis)
• Carbazoles (analysis, chemistry)
• Cytochrome P-450 CYP1A1 (metabolism)
• Dioxins (analysis, chemistry)
• Environmental Monitoring (methods)
• Environmental Pollution (analysis)
• Forests
• Germany
• Halogenation
• Polychlorinated Biphenyls (analysis)
• Polychlorinated Dibenzodioxins
• Rats
• Soil (chemistry)
• Soil Pollutants (analysis)