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Environmental fate & pathways

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One study is available testing the bioconcentration potential of Reaction mass of 1,1'-(isopropylidene)bis[3,5-dibromo-4-(2,3-dibromo-2-methylpropoxy)benzene] and 1,3-dibromo-2-(2,3-dibromo-2-methylpropoxy)-5-{2-[3,5-dibromo-4-(2,3,3-tribromo-2-methylpropoxy)phenyl]propan-2-yl}benzene in fish. Since the study shows some limitations a QSAR was additionally conducted in order to gain a better impression of the bioaccumulative potential of the substance.

 

In the study conducted according OECD 305, Cyprinus carpio (carp) was exposed for 63 d to two concentration levels of 0.01 mg/L and 0.001 mg/L (nominal). The BCF was found to lie between <9 and 45 at the high concentration level of the test item and between <76 and 94 at the low concentration level. However, the study shows some limitations. A solvent (tetrahydrofuran) was used as a vehicle in a higher concentration than recommended by the guideline. The BCF steady state could not be calculated and the bioconcentration factors were not corrected for lipid content.

 

Therefore, an additional QSAR calculation (BCFBAF v3.01, EPISUITE v 4.11) was performed and resulted to a BC factor of 60.74 L/kg for the upper trophic including a biotransformation rate of 0.0001852 /day (for 10 g fish). This result further indicates a low bioaccumulative potential of the substance. The substance does not meet completely the applicability domain of the model and results have to be carefully observed.

 

Physicochemical and toxicokinetic data give additional hints about the bioaccumulative fate of Reaction mass of 1,1'-(isopropylidene)bis[3,5-dibromo-4-(2,3-dibromo-2-methylpropoxy)benzene] and 1,3-dibromo-2-(2,3-dibromo-2-methylpropoxy)-5-{2-[3,5-dibromo-4-(2,3,3-tribromo-2-methylpropoxy)phenyl]propan-2-yl}benzene. The substance has a high molecular weight of 971.68 g/mol and a high log Kow of > 10 (OECD 117). According to guideline (EC) No 1907/2006 these parameters indicate low bioaccumulation potential of the substance due to limited bioavailability. The toxicokinetic assessment also states a very low potential of absorption by the oral or the dermal route. No deaths or systemic toxicity were observed in acute oral or dermal toxicity studies. The high molecular weight indicates low potential of the substance to be absorbed through intestinal wall and enter the systemic circulation. Additionally, the substance is very insoluble in liquid solutions so it's not easily to be dissolved in gastrointestinal fluids (for more details see section 7.1). Furthermore, no toxic effects were observed in any of the aquatic toxicity studies.

 

Based on this wide range of evidence a low bioaccumulation potential of the substance in biota is expected.