An overview of brominated flame retardants in the environment.

Brominated flame retardants (BFRs) have routinely been added to consumer products for several decades in a successful effort to reduce fire-related injury and property damage. Recently, concern for this emerging class of chemicals has risen because of the occurrence of several classes of BFRs in the environment and in human biota. The widespread production and use of BFRs; strong evidence of increasing contamination of the environment, wildlife, and people; and limited knowledge of potential effects heighten the importance of identifying emerging issues associated with the use of BFRs. In this article, we briefly review scientific issues associated with the use of tetrabromobisphenol A, hexabromocyclododecane, and three commercial mixtures of polybrominated diphenyl ethers and discuss data gaps. Overall, the toxicology database is very limited; the current literature is incomplete and often conflicting. Available data, however, raise concern over the use of certain classes of brominated flame retardants.

https://www.jstor.org/stable/pdfplus/3435788.pdf

Brominated flame retardants: cause for concern?

Novel brominated flame retardants : A review of their analysis, environmental fate and behaviour

Polybrominated diphenyl ethers (PBDEs) have been widely used to flame-retard products common in homes and the workplace, and subsequently, they have become widely dispersed in the environment. Detailed compositional knowledge of these complex PBDE mixtures is crucial to a fuller understanding of their toxicological potencies and environmental fate due to selective congener biomagnification, degradation, and transport. Utilizing recenttechnical enhancements and newly available commercial standards, we developed a method capable of analyzing a larger suite of mono- through deca-BDEs. We then characterized the congener composition of six common technical flame-retardant mixtures: two penta-BDE products (DE-71 and Bromkal 70-5DE) two octa-BDE products (DE-79 and Bromkal 79-8DE) and two deca-BDE products (Saytex 102E and Bromkal 82-0DE). PBDEs were analyzed by gas chromatography/mass spectrometry (GC/MS). Structural conformations based on fragmentation patterns and molecular ions were established by electron-capture negative ionization (ECNI) and electron ionization (El). Sixty-four commercially available PBDE standards were chromato-graphed on two GC columns (DB-1HT and DB-5HT) and relative retention indexes (RRI) calculated. Thirty-nine PBDEs were identified in these products, 29 at concentrations >0.02% by weight. Of these, 12 previously unreported congeners have been confirmed as commercial mixture components. Four of these congeners were detected >0.02% w/w (BDE-144, -171, -180, and -201) and three (BDE-75, -184, and -194) at <0.02%. Five other congeners (four <0.02% by weight) were tentatively identified based on their molecular ion and ECNI fragmentation in the absence of corresponding analytical standards.

Detailed polybrominated diphenyl ether (PBDE) congener composition of the widely used penta-, octa-, and deca-PBDE technical flame-retardant mixtures.

Polybrominated diphenyl ethers (PBDEs) are used as flame retardants in plastics (concentration, 5--30%) and in textile coatings. Commercial products consist predominantly of penta-, octa-, and decabromodiphenyl ether mixtures, and global PBDE production is about 40,000 tons per year. PBDEs are bioaccumulated and biomagnified in the environment, and comparatively high levels are often found in aquatic biotopes from different parts of the world. During the mid-1970--1980s there was a substantial increase in the PBDE levels with time in both sediments and aquatic biota, whereas the latest Swedish data (pike and guillemot egg) may indicate that levels are at steady state or are decreasing. However, exponentially increasing PBDE levels have been observed in mother's milk during 1972--1997. Based on levels in food from 1999, the dietary intake of PBDE in Sweden has been estimated to be 0.05 microg per day. Characteristic end points of animal toxicity are hepatotoxicity, embryotoxicity, and thyroid effects as well as maternal toxicity during gestation. Recently, behavioral effects have been observed in mice on administration of PBDEs during a critical period after birth. Based on the critical effects reported in available studies, we consider the lowest-observed-adverse-effect level (LOAEL) value of the PBDE group to be 1 mg/kg/day (primarily based on effects of pentaBDEs). In conclusion, with the scientific knowledge of today and based on Nordic intake data, the possible consumer health risk from PBDEs appears limited, as a factor of over 10(6) separates the estimated present mean dietary intake from the suggested LOAEL value. However, the presence of many and important data gaps, including those in carcinogenicity, reproduction, and developmental toxicity, as well as additional routes of exposure, make this conclusion only preliminary. Moreover, the time trend of PBDEs in human breast milk is alarming for the future.

Polybrominated diphenyl ethers: occurrence, dietary exposure, and toxicology.

Formation of brominated dibenzofurans from the photolysis of flame retardant decabromobiphenyl ether in hexane solution by UV and sun light.

Polybrominated biphenyl ethers in marine fish, shellfish and river and marine sediments in Japan

Identification of the flame retardant tetrabromobisphenol-A in the river sediment and the mussel collected in Osaka.

The flame retardant tetrabromobisphenol-A and its metabolite found in river and marine sediments in Japan

Long-term studies on the concentrations of polychlorinated biphenyls (PCBs) in the blood of children and their mothers occupationally exposed to PCBs were made during the period 1975 to 1979. This report deals in particular with the rates of decrease and half-lives of PCB concentrations in the blood. Rates of decrease of the concentration of PCBs in the blood of both mothers and their children were relatively constant and independent of PCB concentrations. Therefore, a one-compartment model equation was sufficient to represent the decrease of the concentrations of PCB in the blood. The mean rate constant of the decrease of PCB concentration for the children was approximately 2.6 times higher than that of the mothers.

Isao Watanabe

Papers

Formation of brominated dibenzofurans from the photolysis of flame retardant decabromobiphenyl ether in hexane solution by UV and sun light.

Polybrominated biphenyl ethers in marine fish, shellfish and river and marine sediments in Japan

Identification of the flame retardant tetrabromobisphenol-A in the river sediment and the mussel collected in Osaka.

The flame retardant tetrabromobisphenol-A and its metabolite found in river and marine sediments in Japan

Rate of decrease and half-life of polychlorinated biphenyls (PCBs) in the blood of mothers and their children occupationally exposed to PCBs