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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

Not readily biodegradable according to OECD criteria, poorly biodegradable.

Key value for chemical safety assessment

Additional information

Data on biodegradation 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 readily biodegradability of CGX UVA 006 was tested in a GLP guideline study conducted in compliance with OECD 301B. Based on the determined CO2 evolution no biodegradation within 28 days was detected (RCC Ltd., 2002). The result is supported by a second study set up according to OECD guideline 301C. The O2 consumption of activated sludge was recorded for 28 days and a degradation rate of 0 -3 % was determined (Ciba Specialty Chemicals Inc., 2002).

CG 35-1597 was also not readily biodegradable according to an EPI Suite calculation using BIOWIN v4.10 (US EPA EPIWEB v4.1).