Benzaldehyde, 5-dodecyl-2-hydroxy-, oxime, branched

Biodegradation in water: screening tests

Description of key information

Not biodegradable: 0% biodegradation in 28 days test period (OECD 302C, read across)

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

Since no studies assessing the biodegradability of Benzaldehyde, 2-hydroxy-5-dodecyl-, oxime, branched (CAS 1233873-37-4) is available, in accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5 Grouping of substances, a read-across to the structurally related source substance Benzaldehyde, 2-hydroxy-5-nonyl, oxime, branched (CAS 174333-80-3) was conducted. The only structural difference between the source substance and the target substance is the slightly (two C-atoms) shorter carbon chain of the source substance at the the phenol ring. The read across is justified due to (i) the similarity of structure and functional groups and accordingly (ii) similar physico-chemical properties resulting in a similar environmental fate and ecotoxicity profile:

Table 1: Physico-chemical properties, efate and ecotoxicological profile of the target and the source substance

Substance	Benzaldehyde, 2-hydroxy-5 -dodecyl, oxime, branched	Benzaldehyde, 2-hydroxy-5-nonyl, oxime, branched
CAS number	1233873-37-4	174333-80-3
Structure	see attachment	see attachment
Molecular formula	C19H31N1O2	C16O2N1H25
Molecular weight	~ 305.46 g/mole	~ 263 g/mole
PC parameter
Water solubility	0.3 mg/L (OECD 105)	0.4 mg/L (EU method A.6)
Partition coefficient	> 5.7 (EU method L3B3 A/63 -73)	5.5 (EU method A.8)
Vapour pressure	< 0.39 Pa at 20 °C (estimation based on Grain-Watson method )	0.37 Pa at 20 °C (OECD 104)
Environmental fate
Biodegradability	-	0 % in 28 days (OECD 302c)
Adsorption [log KOC]	4.4 (OECD 121)	3.7 (OECD 121)
Hydrolysis	not relevant due to low water solubility
Ecotoxicology
Short-term toxicity to fish [96h-LC50]	-	1.1 mg/L (EU method C.1)
Short-term toxicity to aquatic invertebrates [48h-EC50]	-	2.7 mg/L (EU method C.2)
Long-term toxicity to aquatic invertebrates [21d-NOEC]	-	0.189 mg/L (OECD 211)
Short-term toxicity to algae [72h-EC50]	498.32 mg/L (OECD 201)	36.3 mg/L (OECD 201)
Long-term toxicity to algae [72h-NOEC]	101.2 mg/L (OECD 201)	14.9 mg/L (OECD 201)
Toxicity to microorganisms [3h-EC10]	-	200.4 mg/L (OECD 209)

The inherent biodegradation study with the source substance was performed according to GLP and OECD guideline 302C using non-adapted activated sludge as inoculum (Seyfried 2007). The biochemical oxygen demand (BOD) of the test substance in the test media was in the normal range found for the inoculum controls. Thus, the test substance was not biodegradable under the test conditions within 28 days.

In addition, several screening tests for Phenol, dodecyl-, branched (CAS 121158-58-5) are available in the respective REACH dossier published in the ECHA database (see table 2). In general, these tests show that Phenol, dodecyl-, branched is not readily biodegradable according to OECD criteria. However, degradation is observed (25% in 28 days) indicating Phenol, dodecyl-, branched to be inherently biodegradable.

Table 2: biodegradation test results for Phenol, dodecyl-, branched based on data from the respective REACh dossier.

Test	Result	Reliability	Reference
OECD 301B	25% in 28 days (10 mg/L) 6% in 28 days (20 mg/L)	4 (RL2 given in dossier)	http://apps.echa.europa.eu/registered/data/dossiers/DISS-a0013377-90c2-2db6-e044-00144f67d031/AGGR-7c12bdcd-229a-49fc-a23b-257f5998259c_DISS-a0013377-90c2-2db6-e044-00144f67d031.html#AGGR-7c12bdcd-229a-49fc-a23b-257f5998259c
OECD 302D	10% in 56 days (adaption not specified)	4 (RL1 given in dossier)	http://apps.echa.europa.eu/registered/data/dossiers/DISS-a0013377-90c2-2db6-e044-00144f67d031/AGGR-37593b91-acf6-4a5d-acb1-c1debc584f8b_DISS-a0013377-90c2-2db6-e044-00144f67d031.html#AGGR-37593b91-acf6-4a5d-acb1-c1debc584f8b