Registration Dossier

Administrative data

Link to relevant study record(s)

Description of key information

Key value for chemical safety assessment

Additional information

The remarks on the toxicokinetics of 2,2',6,6'-Tetrabromo-4,4'-isopropylidenediphenol, oligomeric reaction products with Propylene oxide and n-butyl glycidyl ether are based on physicochemical properties of the compound and on toxicological data. Experimental toxicokinetic studies were not performed.

The substance is a colourless solid. (Neuland, 2012) with a very low vapour pressure under normal ambient conditions (0.00092 Pa at 20 °C, Fonseca, 2012). Inhalation exposure via vapour is therefore to be negligible.

The physico-chemical characteristics of the substance (water solubility was determined as below the limit of quantification (= 0.0051 g/L at 20°C, Neuland, 2012), log Pow of 4.8 at 25°C (Garcia-Sanchez, 2012)) and a molecular mass of ca. 549 g/mol (Esser, 2012) suggest a low intestinal absorption after oral intake. This assumption is at first not confirmed by the data on acute oral toxicity in rats (LD50= approx. 732 mg/kg bw, Gardner, 1989) and the results of a subacute oral study in rats (Wirnitzer, 2013) with a NOAEL of 5 mg/kg bw and 10 mg/kg bw for the female and male rat with regard to inflammatory changes of the intestine (mainly cecum). On closer analysis it becomes obvious that lethality in the acute toxicity study as well as intestinal histopathology in the subacute study is a consequence of functional impairment of the intestine through local effect of the test substance and thus do not contradict the assumption of low intestinal absorption.

Due to the negligible low water solubility, a log Pow of 4.8 at 25°C and a molecular mass of ca. 549 g/mol no appreciable dermal or mucosal absorption is anticipated. This is confirmed by the studies on acute dermal toxicity (rat, LD50 > 2000 mg/kg bw; Gardner, 1989), eye irritation and on skin sensitization (GPMT, Gardner, 1989) in which no signs of systemic toxicity were observed.

Deducing from the repeated dose toxicity study, where no systemic toxicity was reported, no potential for accumulation is to be expected for the substance although the log Pow suggests some lipophilicity.

Based on the results of in vitro genotoxicity tests (negative with and without metabolic activation in Ames test, Gardner, 1989; HPRT test, Wollny, 2013; Micronucleus test, Sutter, 2013) it is concluded that DNA-reactive metabolites of 2,2',6,6'-Tetrabromo-4,4'-isopropylidenediphenol, oligomeric reaction products with Propylene oxide and n-butyl glycidyl ether will most probably not be generated in mammals in the course of hepatic biotransformation if bioavailability is given.