1,4-diisopropylbenzene

Bioaccumulation: aquatic / sediment

Description of key information

This endpoint is not mandatory for this tonnage band. However, the following data is reported:
BCF studies, OECD 305 guideline study, BCF values of 1902.4 L/Kg and 1919.4 L/Kg at two exposure concentrations of 10 and 100 µg/L, respectively.

Key value for chemical safety assessment

BCF (aquatic species):

1 919.4

Additional information

The bioconcentration factor (BCF) of a mixture of isomers 1,3-diisopropylbenzene (1,3-DIPB) and 1,4-diisopropylbenzene (1,4-DIPB) was tested in the first Key study (Lejon, 2020) at two different concentrations in the bluegill (Lepomis macrochirus), through aqueous exposure based on the OECD TG 305 (2012). Four different conditions were used during the test: (i) Control, (ii) Solvent Control, (iii) DIPB mixture at 10 μg.L-1(nominal concentration) (DIPB10) and (iv) DIPB mixture at 100 μg.L-1(nominal concentration) (DIPB100). The test was divided into two phases, the uptake phase which lasted 14 days followed by a depuration phase. The total duration of the test lasted 29 days. No toxic effect of the test item and/or the solvent control were observed. In this study the BCFKgL based on first order kinetics was in the same order of magnitude than the BCF_SSL, indicating clearly that a steady-state has been attained in the uptake phase.

By comparing BCF_KgL between conditions (DIPB10 and DIPB100) for both isomers (and consequently for the mixture), it is important to note as well that the difference is not clearly marked with 5 % and 1 % of difference, respectively.  This lack of clear difference between BCF_KgL obtained in each condition confirmed as well as the low impact of the noted deviation of the study plan. This deviation regarded that the concentration of the test substance in the test chambers was not maintained within +/- 20 % of the mean of the measured values during the uptake phase.

By consequence, the BCF_KgL(L.kg-1) obtained in this study for the test item (mixture of isomers DIPB) was between 1785.1 and 1828.7.

The BCF_KgL(L.kg-1) for the 1,3-DIPB isomer was between 1628.2 and 1708.9, and the BCF_KgL(L.kg-1) for the 1,4-DIPB isomer was between 1902.4 and 1919.4.

These results suggest that the individual isomers as well as the mixture of isomers do not meet the Bioaccumulation (B) threshold of 2000 under a PBT/vPvB assessment.

 

The second Key BCF study conducted according to OECD Guideline 305 E (Bioaccumulation: Flow-through Fish Test) Cyprinus carpio were exposed to the mixed isomers m-/p-diisopropylbenzene concentrations of 2 and 20 µg/L for 56 d.

BCF values were measured for each isomer independently. For p-diisopropylbenzene BCF values ranging from 530 to 2300 at 20 µg/L and 512 to 2960 at 2 µg/L were determined and for m-diisopropylbenzene BCF values ranging from 503 to 1680 at 20 µg/L and 546 to 3210 at 2 µg/L. 

 

In conclusion, the test item does not meet the classification criteria for B or vB.