Environmental hazard profile

• Author: Clemm, Christan; Löw, Clara; Baron, Yifaat; Moch, Katja; Möller, Martin; Köhler, Andreas R; Gensch, Carl-Otto; Deubzer, Otmar
• Pages: 25-27

RoHS Annex II Dossier, final

TBBP-A (flame retardant)

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4. ENVIRONMENTAL HAZARD PROFILE

According to the harmonised classification and labelling, TBBP-A is very toxic to aquatic life and is

very toxic to aquatic life with long lasting effects.

The environmental hazard evaluation process for TBBP-A, which concerns the endocrine disruptive

as well as the PBT properties, is still ongoing66 and will be pending until at least 2021.67

Nevertheless, some preliminary information on adverse impacts on biota has been gathered as a

result of various studies:

• The endocrine disruptive properties of TBBP-A may cause effects on the thyroid hormone system

of aquatic organisms by possible interference with oestrogen signalling. This concern was

expressed by the Danish EPA and is based on various studies including both in vitro and in vivo

assays. This concern is currently being analysed by means of a Larval Amphibian Growth and

Development Assay (LAGDA) (test method: OECD 241).

• The persistency of one transformation product of TBBP-A, monomethyl ether TBBP-A (Phenol,

4,4 -(1-methylethylidene)-bis[2,6-dibromo-) is under evaluation. Further information will be

requested in respect to the bioaccumulation potential and potentially hereafter on the chronic

toxicity towards aquatic organism and/or mammalian species.

The following sections on the environmental properties are based on data of the EU RAR (2008)68

and from the ECHA Registered Substance Database.69

4.1. Environmental fate properties

The EU RAR (2008) concludes that TBBP-A is persistent or potentially very persistent according to

the criteria used under REACH. It is understood that primary biodegradation occurs only under

specific environmental circumstances, e.g. under anaerobic conditions. The main degradation

product found was bisphenol-A (BPA), which is persistent under anaerobic conditions (EU RAR

2008). BPA is recognised as SVHC for endocrine disrupting properties for the environment as well

as for human health.

According to the ECHA Decision on Substance Evaluation (2017), TBBP-A transforms in natural

sediments to monomethyl ether TBBP-A, a substance that is also suspected of meeting PBT criteria.

McCormick et al. (2010)70 examined the relative toxicity of TBBP-A and it’s two known degradations

products BPA and TBBP-A DME using the exposure model of embryonic zebrafish. Their data

showed “an increase in embryo or larval mortality following developmental exposure to TBBP-A or

BPA. TBBP-A DME exposure, however, did not result in death as compared to control embryos after

one-week post-fertilization. TBBP-A proved to be 10 times more potent than BPA or TBBPA DME

exposure.”

66 Op. cit. ECHA Substance Evaluation Decision (2017)

67 The test results have to be submitted by 04.01.2021; thereafter the MSCA have to review the submission.

68 Op. cit. EU RAR 2008

69 Op. cit. ECHA Registered Substances Database: Entry for 2,2',6,6'-tetrabromo-4,4'-isopropylidenediphenol (2019)

70 McCormick et al. Embryonic exposure to tetrabromobisphenol A and its metabolites, bisphenol A and

tetrabromobisphenol A dimethyl ether disrupts normal zebrafish (Danio rerio) development and matrix

metalloproteinase expression Aquatic Toxicology100 (2010) 255–262