# Chemicals from Brominated Flame Retardants: Analytical Methods, Occurrence, Transport and Risks
## 1 Introduction  
Brominated Flame Retardants (BFRs) are a group of chemicals widely used to reduce the flammability of various materials, including plastics, textiles, and electronics [1]. Their use has been of great societal benefit in improving fire safety. In 2011, 390,000 tons of BFRs were sold, representing 19.7% of the flame retardant market [2]. BFRs encompass a variety of synthetically produced compounds with diverse chemical properties. The main groups include polyforminated diphenyl ethers (PBDEs), such as DecaBDE, OctabDE (no longer manufactured), and PentaBDE (no longer manufactured), first commercialized in the 1950s); polybrominated biphenyls (PBBs) (no longer manufactured); brominated cyclohydrocarbons; and other brominated flame retardants with various properties and mechanisms [3, 4]. Novel BFRs (NBFRs) have surfaced after the prohibition on PBDEs and HBCDD [5]. Emerging contaminants, or NBFRs, are relatively new to the market, present in products, and have the potential to enter the environment. Because of their diverse physico-chemical characteristics, these \"novel\", \"emerging\", or \"new\" BFRs have a wide variety of applications in goods including plastics, foams, textiles, furniture, and electrical devices [6]. Research points to possible hazards to human health and the environment from NBFR exposure [7]. BFR-treated items pollute the air, land, and water when they are used or disposed of. These pollutants can then make their way up the food chain, where they are mostly found in foods that come from animals, such milk, fish, meat, and derivatives [8]. There are emerging concerns due to their persistence, bioaccumulation, and potential adverse effects on human health and the environment which have been demonstrated in studies. [PERSON] et al. [9] investigated the mechanism by which brominated flame retardants (BFRs) affect proteins, using human serum albumin (HSA) as a model system. They examined interactions between selected BFRs--tetrabromobisphenol A (TBBPA), tetrabromobisphenol S (TBBPS), 2,4-dibromophenol (2,4-DBP), 2,4,6-tribromophenol (2,4,6-TBP), and pentabromophenol (PBP)--and HSA by measuring intrinsic tryptophan fluorescence and circular dichroism (CD) absorbance. Additionally, to understand the potential effects of these compounds in their native environment, the impact of BFRs on membrane proteins of human erythrocytes (red blood cells, RBCs) was assessed. The study revealed that among the bromophenols, PBP exhibited the strongest oxidative effect on RBC membranes, whereas 2,4-DBP demonstrated the weakest fluorescence-quenching effect on both membrane tryptophan and HSA. In contrast to PBP, both 2,4-DBP and 2,4,6-TBP induced spatial changes in HSA. Notably, TBBPA was found to cause the most significant oxidation of RBC membrane proteins and the model HSA protein, leading to a reduction in tryptophan fluorescence. TBBPA also altered the conformational properties of albumin, impairing the \(\alpha\)-helix structure. These findings highlight the differential impact of various BFRs on protein structure and function, with TBBPA showing the most pronounced effects. Due to insufficient information on incidence and toxicity, the European Food Safety Authority (EFSA) was unable to conduct risk assessments for newly developed and novel brominated flame retardants (NBFRs) in food, even after publishing a scientific paper on the topic [4]. In response, the European Commission issued recommendations (Directive 2014/118/EU) for detecting BFR residues in food, including NBFRs such as 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (EH-TBB) [10]. This limitation stems from the lack of comprehensive studies and information on analytical techniques. Therefore, this review focuses on the analytical methods used for the detection and quantification of BFRs, their occurrence in various environmental matrices, their transport mechanisms, and the associated risks. Analytical methods play a crucial role in the assessment of BFR contamination [11; 12].