Brominated flame retardants
- The text on this page is taken from an equivalent page of the IEHIAS-project.
There are three major classes of BFRs in Europe:
- tetrabromobisphenol A (TBBPA),
- hexabromocyclododecane (HBCD)
- three commercial mixtures of polybrominated diphenyl ethers (PBDEs), namely deca-BDE, octa-BDE and penta-BDE.
Europe has banned the use of penta- and octa-BDE in electrical and electronic equipment. Deca-BDE is the main PBDE of concern, and consists of a mixture of 97-98% BDE-209.
Brominated flame retardants as a biomarker
Sample collection and storage
Matrix:
BFRs can be determined in blood and adipose tissue, although breast milk is often preferred
Kinetics:
- Major uptake routes include food (fatty fish, milk products), inhalation of dust particles and directly through aerial exposure
- TBBPA and DeBDE have very low uptake rates, with 90-99% of the dose eliminated in feces and gut
- Daily PBDE intake ranges from 0.0001-2.6 µg/kg bw, depending on which congeners considered
- Half-life of Deca-BDE is 11-18 days, and 2 days for TBBPA
Sampling conditions:
Although routine procedures are appropriate for sampling and storing samples, the omnipresence of BFRs is an obvious contamination risk. Samples are stored at -20°C.
Sample measurement
Analytical aspects:
- Methods generally are analyzed using GC-MS, with a wide variety of pretreatment, extraction and clean-up procedures
- LOD in human milk is 0.3-0.7 pg/g milk for PBDEs
- LOQ is < 10 pg/g serum fat or breast milk for TBBPA and 30-1500 pg/g for HBCD and deca-BDE
Performance characteristics:
- Analytical reproducibility imprecision is around 25% for Deca-BDE and HBCF.
- Repeatability is in the range of 5-9% and 1-10% relative standard deviation
- Reliable quantification of Deca-BDE, HBCD and TBBPA remains a problem, with reported CV% of 63% and 53%
Validation:
No uniform, internationally accepted guidelines for BFRs in biological matrices developed yet
Confounding factors:
Occupation (e.g. computer work) and diet may be important confounders
Data interpretation
Concentrations reported in literature:
- BFR concentrations are increasing in the general population, with a doubling of dose every 5 years.
- Concentrations in North America are 10 times higher than in Europe or Japan
Dose-response/effect relationships:
- A general lack of high-quality toxicity data on BFRs
- Acute toxicity is low and no mutagenic potency has been observed.
- Epidemiological studies generally have not shown adverse effects of occupational exposure
Time trend, geographical variation, susceptibel groups:
- An exponential increase in BFRs with a doubling time of 5 years
- Recent data seem to indicate that levels are stabilizing again
- Apart from occupational exposure, no obvious susceptible groups are identified