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Sources and toxicities of phenolic polychlorinated biphenyls (OH-PCBs)
Journal article   Peer reviewed

Sources and toxicities of phenolic polychlorinated biphenyls (OH-PCBs)

Kiran Dhakal, Gopi S Gadupudi, Hans-Joachim Lehmler, Gabriele Ludewig, Michael W Duffel and Larry W Robertson
Environmental science and pollution research international, Vol.25(17), pp.16277-16290
06/2018
DOI: 10.1007/s11356-017-9694-x
PMCID: PMC5785587
PMID: 28744683

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Abstract

Polychlorinated biphenyls (PCBs), a group of 209 congeners that differ in the number and position of chlorines on the biphenyl ring, are anthropogenic chemicals that belong to the persistent organic pollutants (POPs). For many years, PCBs have been a topic of interest because of their biomagnification in the food chain and their environmental persistence. PCBs with fewer chlorine atoms, however, are less persistent and more susceptible to metabolic attack, giving rise to chemicals characterized by the addition of one or more hydroxyl groups to the chlorinated biphenyl skeleton, collectively known as hydroxylated PCBs (OH-PCBs). In animals and plants, this biotransformation of PCBs to OH-PCBs is primarily carried out by cytochrome P-450-dependent monooxygenases. One of the reasons for infrequent detection of lower chlorinated PCBs in serum and other biological matrices is their shorter half-lives, and their metabolic transformation, resulting in OH-PCBs or their conjugates, such as sulfates and glucuronides, or macromolecule adducts. Recent biomonitoring studies have reported the presence of OH-PCBs in human serum. The occurrence of OH-PCBs, the size of this group (there are 837 mono-hydroxyl PCBs alone), and their wide spectra of physical characteristics (pKa's and log P's ranging over 5 to 6 orders of magnitude) give rise to a multiplicity of biological effects. Among those are bioactivation to electrophilic metabolites that can form covalent adducts with DNA and other macromolecules, interference with hormonal signaling, inhibition of enzymes that regulate cellular concentrations of active hormones, and interference with the transport of hormones. This new information creates an urgent need for a new perspective on these often overlooked metabolites.
Cytochrome P-450 Enzyme System - chemistry Animals Polychlorinated Biphenyls - chemistry Environmental Pollutants Polychlorinated Biphenyls - toxicity Hydrocarbons, Chlorinated - chemistry Humans Sulfates - chemistry Cytochrome P-450 Enzyme System - metabolism ISRP Project 1 2015-2020 ISRP Project 3 2015-2020 Synthesis Core

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