Enzyme-mediated formation of 2,3,7,8-tetrasubstituted chlorinated dibenzodioxins and dibenzofurans

Svenson, Anders; Kjeller, Lars Owe; Rappe, Christoffer

doi:10.1021/es00065a022

Cited by 88 publications

(31 citation statements)

References 4 publications

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“…Subsequent biochemical (enzymatic) and chemical reactions may lead to the transformation of suitable precursors into more complex structures. Enzymatic and photochemical formation of PCDD/Fs from precursors has been demonstrated under laboratory conditions (Svenson et al 1989;Vollmuth et al 1994). Evidence for natural formation of di-to tetrachlorinated dibenzo-p-dioxins and dibenzofurans in forest soils has also been presented (Hoeksta et al 2000).…”

Section: Sedimentsmentioning

confidence: 97%

Levels and congener distributions of PCDDs, PCDFs and dioxin-like PCBs in environmental and human samples: a review

Srogi

2007

Environ Chem Lett

176

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The term ''dioxins'' is often used in a confusing way. In toxicological considerations-and also in the present report-the term is used to designate the PCDDs, the PCDFs and the coplanar (''dioxin-like'') PCBs, since these classes of compounds show the same type of toxicity. Because of the large number of congeners, relevant individual congeners are assigned with a toxic equivalency factor (TEF) that relate their toxicity to that of tetrachlorodibenzo-p-dioxin (TCDD) (2,3,7,8-TCDD) and are to be evaluated as dioxins. Each concentration of an individual congener in a mixture is multiplied with its TEF, and the resulting TCDD equivalents are added up and expressed as WHO-endorsed toxic equivalents (WHO-TEQ). Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are mainly the by-products of industrial processes (such as metallurgical processing, bleaching of paper pulp, and the manufacturing of some herbicides and pesticides) but they can also result from natural processes like volcanic eruptions and forest fires. Waste incineration, particularly if combustion is incomplete, is among the largest contributors to the release of PCDDs and PCDFs into the environment. Due to their persistence, PCDDs, PCDFs and PCBs are part of the socalled persistent organic pollutants group of compounds that also include some chlorinated pesticides. Since they have a high lipophilicity and resist transformation, they bio-accumulate in animal and human adipose tissues. Consumption of food is considered as the major source of non-occupational human exposure to PCDD/Fs with foodstuffs from animal origin accounting for more than 90% of the human body burden. With meat, dairy, and fish products being the main contributors. The aim of the present review was to summarize experimental data regarding dioxin emissions from contaminated and uncontaminated biological and environmental samples, from the available literature. The information will be presented chronologically with respect to distribution in human milk, serum; food, water, air, soils and sediments.

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Section: Sedimentsmentioning

confidence: 97%

Levels and congener distributions of PCDDs, PCDFs and dioxin-like PCBs in environmental and human samples: a review

Srogi

2007

Environ Chem Lett

176

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“…DD-and MCDD-degrading activity was found in other wood-rot fungi belonging to the genera Aleurodiscus, Ceriporia, Phanerochaete and Phlebia, in addition to some unidentified strains 126) . Some investigators reported peroxidase-catalyzed polymerization of chlorophenols to PCDD/Fs 138,177) . The radical polymerization of phenolics is a characteristic feature of the peroxidase system.…”

Section: )mentioning

confidence: 99%

Biodiversity of Dioxin-Degrading Microorganisms and Potential Utilization in Bioremediation.

Hiraishi

2003

Microb. Environ.

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Dioxins are a group of chloroaromatic compounds known to be toxic and carcinogenic, and persistent environmental pollutants. How to remedy dioxin-polluted environments is one of the most challenging problems in environmental technology. From ecological and economical viewpoints, biological methods using particular microorganisms and microbial consortia capable of dioxin transformation and degradation have greater appeal than physicochemical methods in their application for environmental remediation. Large numbers of microorganisms capable of degrading dioxins and dioxin-like compounds have been isolated and characterized. Information about the biodiversity, ecophysiology and molecular biology of dioxin-degrading microorganisms has accumulated particularly during the past decade. There are three major modes of microbial degradation and transformation of dioxins; that is, oxidative degradation by aerobic bacteria containing aromatic hydrocarbon dioxygenases, reductive dechlorination by anaerobic microorganisms and fungal oxidation with cytochrome P-450, lignin peroxidases and laccases. This article overviews the current knowledge of microbial degradation and transformation of dioxins as well as the biodiversity of microorganisms involved. Strategies directed towards the bioremediation of dioxin-polluted environments are discussed.

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“…dioxins). So toxicity aspects must be dealt with carefully and each case must be studied separately (Svenson et al 1989;0berg et al 1990). …”

Section: Chemical Bindingmentioning

confidence: 99%

Formation of non-bioavailable organic residues in soil: Perspectives for site remediation

Verstraete

Devliegher

1997

Biodegradation

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Enzyme-mediated formation of 2,3,7,8-tetrasubstituted chlorinated dibenzodioxins and dibenzofurans

Cited by 88 publications

References 4 publications

Levels and congener distributions of PCDDs, PCDFs and dioxin-like PCBs in environmental and human samples: a review

Levels and congener distributions of PCDDs, PCDFs and dioxin-like PCBs in environmental and human samples: a review

Biodiversity of Dioxin-Degrading Microorganisms and Potential Utilization in Bioremediation.

Formation of non-bioavailable organic residues in soil: Perspectives for site remediation

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