Flame Retardants: New and Old Environmental Contaminants

Abstract

Flame retardants are a group of compounds used in a variety of consumer goods to inhibit or retard the spread of flames. Several classes of chemical compounds have such capabilities, however, the persistence of these compounds in the environment and their toxicity are crucial points for a risk assessment. Classes such as polybrominated diphenyl ethers (PBDEs) have already been banned in some parts of the world while they are still permitted and extensively used in other parts of the globe. In the need for substitutes for the toxic compounds used, new structures have been synthesized and suggested by the industry as an alternative and substitutives flame retardants. The objective of this review is to address the classes of compounds used as flame retardants in terms of their toxicity to human or non-human organisms and their persistence in the environment.

An overview of the (eco)toxicological effects of flame retardants emerging in water and sediment

“…PBDEs, NBFRs, and OPFRs production, their leaching from the materials, and improper discharge are major sources of environmental contamination. Reuse and recycling of materials containing these FRs, including electronic waste, upholstery, and furniture, may also have a limited impact on the environment (Miranda et al, 2022). The occurrence of FRs in the environment is shown in Figure S1.…”

“…Differences in the physicochemical properties of FRs affect the considerable variety in the presence and concentration of these groups of FRs in water and sediment. Lipophilic, hydrophobic, and low vapour pressure properties of PBDEs influence their appearance in sediments, eatables, and particles and droplets in the air (Miranda et al, 2022). Lipophilic properties of NBFRs influence their high accumulation levels in aquatic organisms, and further spread through the food chain; thus their concentration in water is lower, such as for DBDPE or BTBPE -Table S2 (Hou et al, 2021).…”

“…OPFRs exhibiting lower molecular weight are more likely to be found in water than in sediment. Generally, they are more soluble in water than NFBRs, although the log K OW values indicate the lipophilic properties of several OPFRs (Miranda et al, 2022).…”

“…Although the ability to bioaccumulate is lower compared to halogen HFRs, OPFRs still may pose a significant threat to human and the environment. They may cause endocrine disruption and are related to a high risk for reproduction and systemic toxicity (Miranda et al, 2022). Cristale et al (2013) studied the acute toxicity of the TnBP, TCEP, TCPP, TPHP, EHDPP, TBOEP, TEHP, and TCP (tricresyl phosphate), being the most common contaminants in the three Spanish rivers, on Daphnia magna.…”

“…Regulation of usage and production of HFRs started in 1972 by banning polychlorinated biphenyls (PCBs) being persistent organic pollutants (POPs) (Miranda et al, 2022), that have an adverse effect on the ecosystem and human health. Seeking satisfactory alternatives led to growing interest in brominated FRs (BFRs), which exhibit a similar mode of action.…”