Citation:

Kodavanti, P. AND B. Loganathan. Polychlorinated biphenyls, polybrominated biphenyls, and brominated flame retardants. Chapter 28, Biomarkers in Toxicology. ELSEVIER, AMSTERDAM, Holland, , 501-518, (2019).

Impact/Purpose:

This book chapter is a very informative treatise on PCBs, PBBs and BFRs. Not only it emphasizes the environmental levels and routes of human exposure to these toxicants, but also the human health effects. Additionally, the mechanisms (both biochemical and molecular) that underlie the observed toxicities of these chemicals were given due consideration. Some of the key biochemical endpoints such as enzymes, metabolites and cellular macromolecule (protein, lipids and nucleic acids) changes serve as biomarkers of effect upon exposure to the above-mentioned toxicants. This book chapter provides valuable insights to employing these biomarkers for toxicity studies. This information will be of use when dose-response studies are carried out for risk assessment purposes. The revised narrative in this chapter is supported by recent literature to make the knowledge base current.

Description:

Human activities are responsible for the environmental input of many classes of chemicals through industrial, agricultural, and domestic sources. Biomonitoring studies have clearly shown a wide distribution of PCBs, PBBs, and PBDEs in the biosphere, resulting in exposures to almost all trophic level organisms with consequent adverse biological effects. This chapter presents biomarkers of response to environmental stressors, specifically in relation to the man-made synthetic organic chemicals PCBs, PBBs, and BFRs. Although other biochemical effects such as oxidative stress and neurotransmitter changes have been reported for these chemicals, this chapter concentrates on the current three best prospects of early biomarkers of toxicity. Thyroid hormone disruption, perturbed calcium homeostasis and kinase signaling, and induction of cytochrome-P450 enzymes are described as potential biomarkers of exposure and effect in exposed organisms. Data show that toxicity to these compounds appears at the subcellular level before being observed at individual or population levels. Further research, particularly for the BFRs, on initiating events, common molecular mechanisms, and the consequences of exposure, will improve our ability to determine earlier and better biomarkers of exposure. The relevant use of early biomarkers will improve our ability to assess both ecosystem and human risk.

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