Brominated phenols (BPs) of anthropogenic origin are aromatic substances widely used in the industry as flame retardants (FRs) and pesticides as well as the components of FRs and polymers. In this review, we have focused on describing 2,4-dibromophenol (2,4-DBP), 2,4,6-tribromophenol (2,4,6-TBP) and pentabromophenol (PBP), which are the most commonly used in the industry and are the most often detected in the air, aquatic and terrestrial ecosystems and the human body. This review describes human-related sources of these BPs that influence their occurrence in the environment (atmosphere, surface water, sediment, soil, biota), indoor air and dust, food, drinking water and the human organism. Data from in vitro and in vivo studies showing 2,4-DBP, 2,4,6-TBP and PBP toxicity, including their estrogenic activity, effects on development and reproduction, perturbations of cellular redox balance and cytotoxic action have been described. Moreover, the processes of BPs transformation that occur in human and other mammals, plants and bacteria have been discussed. Finally, the effect of abiotic factors (e.g. UV irradiation and temperature) on BPs conversion to highly toxic brominated dioxins and brominated furans as well as polybrominated biphenyls and polybrominated diphenyl ethers has been presented.

Brominated flame retardants (BFRs) are the compounds used in the industry in order to decrease flammability of various everyday products. The use of BFRs leads to migration of these substances into the environment, which results in the exposure of humans to their action. Although BFRs are widespread in human surrounding, the effect of these compounds on human body has been very poorly assessed. The purpose of this study was to evaluate cytotoxic effects as well as oxidative potential of selected bromophenolic flame retardants such as tetrabromobisphenol A (TBBPA), tetrabromobisphenol S (TBBPS), 2,4,6-tribromophenol (2,4,6-TBP) and pentabromophenol (PBP) on human peripheral blood mononuclear cells (PBMCs) that are crucial for proper functioning of the immune system. The cells were treated with the substances studied in the concentrations ranging from 0.0001 to 100 μg/mL for 1 h or 24 h. The results have shown that the compounds examined reduced PBMCs viability and ATP level as well as increased reactive oxygen species (including hydroxyl radical) formation. Moreover, the substances tested induced lipid peroxidation and caused oxidative damage to proteins in the incubated cells. It has also been noticed that the greatest changes were provoked by tetrabromobisphenol A, while the weakest by TBBPS, which is used as a substitute of TBBPA in the manufacture.

Phenol and chlorinated phenols are widely spread in the environment and human surrounding, which leads to a common environmental and occupational exposure of humans to these substances. The aim of this study was to assess eryptotic changes in human red blood cells treated with phenol, 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP) and pentachlorophenol (PCP). The erythrocytes were incubated with phenols studied in the concentrations ranging from 1 to 100 mu g/inL for 24 h or 48 h. The results of the study revealed that all compounds studied caused phosphatidylserine translocation and increased cytosolic calcium ions level in human erythrocytes. It was also noticed that phenol and chlorophenols caused an increase in caspase-3 and calpain activation, which confirmed that they were capable of inducing suicidal death of erythrocytes. The results also revealed that PCP most strongly altered the parameters studied, while phenol exhibited the weakest eryptotic potential in the incubated cells.

Brominated flame retardants (BFRs) are widely used in many everyday products. Numerous studies have shown that BFRs can be released into the environment. Environmental pollution with these compounds raises concerns about their potentially adverse health effects. The aim of this study was to evaluate the effect of tetrabromobisphenol A (TBBPA), tetrabromobisphenol S (TBBPS), 2,4-dibromophenol (2,4-DBP), 2,4,6- tribromophenol (2,4,6-TBP) and pentabromophenol (PBP) on hemolysis induction and hemoglobin oxidation in human erythrocytes. The erythrocytes were incubated with selected BFRs in a wide concentrations ranging from 0.01 to 100 μg/ml for 24 h, 48 h and 72 h. All compounds studied, exhibited hemolytic potential and induced methemoglobin formation. Hemolytic and oxidative potential of BFRs increased along with the increasing concentrations of the compounds studied and elongation of the incubation time. Our study showed that both the number of aromatic rings and the number of bromine atoms in the molecule of the compounds examined influence hemoglobin oxidation and damage to the cellular membrane. Furthermore, we may conclude that 2,4-DBP is potentially most toxic compound because it causes statistically significant changes at the lowest concentration, while the highest toxicity at the highest concentrations was noted for TBBPA.