1,3-Benzenediol, 4-[4,6-bis([1,1'-biphenyl]-4-yl)-1,3,5-triazin-2-yl]-

Bioaccumulation: aquatic / sediment

Description of key information

Does not significantly accumulate in organisms

Additional information

Data on bioaccumulation of an analogous substance (EC 440-520-9; CGX UVA 006) are available. CG 35-1597 and the analogous substance belong both to the Triphenyl-triazines (same common functional group) and CG 35-1597 is an intermediate for the synthesis of CGX UVA 006. Triphenyl-triazine are large, bulky, non-polar organic compounds used as UV-filter in varnishes and plastics.

CGX UVA 006 only differs from CG 35-1597 by a substituent at one phenol ring. It has an etherified branched carbonyl chain (C8) in para position instead of a hydroxyl group. The different substituents do not have any significant influence on the behaviour of the substances in the environment. Both substances have a very low water solubility (CG 35-1597 <0.0048 mg/L; CGX UVA 006 <0.73 mg/L), a low vapour pressure (CG 35-1597 = 5.3 E-19 Pa; CGX UVA 006 = 5.4 E-22 Pa), a high logPow above 3 (CG 35-1597 = 8.8; CGX UVA 006 = 10.7), a high molecular weight above 450 (CG 35-1597 = 493.565; CGX UVA 006 = 605.78), are not readily biodegradable and due to the low water solubility hydrolysis is not expected. Both substances are stable and no degradation/breakdown products will occur in the environmental compartments. Due to the slightly higher water solubility and the slightly higher logPow of CGX UVA 006 the read across is justified and regarded as worst-case.

A detailed risk assessment and read across justification was send to the german chemical agency BAuA in 2007 with the purpose of a national substance notification (VIIA). The read across justification was accepted by the national agency.

The bioaccumulation potential of CGX UVA 006 was tested in a guideline study following OECD 305 (Institute of Ecotoxicology Co. 2002). Cyprinus carpio were exposed to the substance for 4 weeks. The determined bioconcentration factor was <9. Despite the use of an emulsifier the test is regarded as valid since the high (0.2 mg/L) and the low exposure level (0.02 mg/L) are below the determined water solubility (< 0.73 mg/L).

The results of the analogous substance are supported by the high calculated logKow of 8.8 and the high molecular weight (493.565) of CG 35-1597. Furthermore, the maximum diameter of CG 35-1579 was calculated using CATALOGIC v5.11.2. It resulted in a maximum diameter of 2.10 to 2.15 nm. The arithmetical mean was calculated to be 2.124 nm. According to the guidance on information requirements and chemical safety assessment Chapter R.11 another parameter that directly reflects the molecular size of a substance is the average maximum diameter (Dmax_aver). Very bulky molecules will less easily pass the cell membranes. This results in a reduced BCF of the substance. From a diverse set of chemicals it appeared that for compounds with a Dmax_aver larger than 1.7 nm the BCF value was less than 5000 L/kg. It can be assumed combining the high logKow, the maximum diameter of above 1.7 nm and the high molecular size of the test item that the test item will not easily pass the cell membranes, the uptake is reduced and bioaccumulation will not occur.

Additionally, two different calculations were conducted to support these results. US EPA T.E.S.T using the consensus method resulted in a BCF of 29.77 and CATALOGIC v5.11.2 (BCF base-line model v2.05) revealed a BCF of 13.11. Even though the structural domain was correct with only 36.84 % the results support the overall conclusion in a weight of evidence.

In overall conclusion, regarding all evidence the test item does not significantly accumulate in organisms.