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

Biodegradation in soil

Description of key information

DisT50 = 2.1 - 10.3 days for different branched 4-nonylphenol isomers (read across). 

Additional information

Since no simulation studies assessing the biodegradability of Benzaldehyde, 2-hydroxy-5 -dodecyl, oxime, branched (CAS 1233873-37-4) in soil are available, in accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5 Grouping of substances, a read-across to Phenol, 4-nonyl-,branched (CAS 84852-15-3) was conducted, which is structurally similar to the main component of the substance. The structural difference between the source substance and the target substance is the lack of a aldoxime group at the phenol ring of the molecule and a C9 branched carbon chain instead of a C12 branched carbon chain. The read across is justified by similarity of structure and functional groups and accordingly similar physico-chemical properties, which is expected to result in similar environmental behavior and fate (see table).

Substance	Benzaldehyde, 2-hydroxy-5-nonyl, oxime, branched	Phenol, 4-nonyl, branched^*
CAS number	174333-80-3	84852-15-3
Structure	see attachment (chapter 6.1)	see attachment (chapter 6.1)
Molecular formula	C16O2NH25	C15H24O
Molecular weight	~ 263 g/mole	~ 220.35 g/mole
PC parameter
Water solubility	0.4 mg/L (EU method A.6)	5.7 mg/L (ASTM E 1148-02)
Partition coefficient	5.5 (EU method A.8)	5.4 (OECD 117)
Vapour pressure	0.37 Pa at 20 °C (OECD 104)	~1 Pa at 20 °C (ASTM-D 2879)
Environmental fate
Biodegradability	0 % in 28 days (OECD 302c)	non-adapted inoculum: 0 % in 28 days (OECD 301B)   adapted inoculum: 48.2-62 % in 28 days (OECD 301B)
Adsorption [log KOC]	3.7 (OECD 121)	4.35 - 5.69 (EPA OTS 796.2750)
Hydrolysis	not relevant
Ecotoxicology
Short-term toxicity to fish [96h-LC50]	1.1 mg/L (EU method C.1)	0.05 – 0.22 mg/L (different methods)
Long-term toxicity to aquatic invertebrates [NOEC]	-	0.006 mg/L (ASTM E 1241-05)
Short-term toxicity to aquatic invertebrates [48h-EC50]	2.7 mg/L (EU method C.2)	0.08 – 0.14 mg/L (different methods)
Long-term toxicity to aquatic invertebrates [21d-NOEC]	0.189 mg/L (OECD 211)	0.024 - 0.116 mg/L (different methods)
Short-term toxicity to algae [72h-EC50]	36.3 mg/L (OECD 201)	0.33 - 1.3 mg/L (different methods)
Long-term toxicity to algae [72h-NOEC/EC10]	14.9 mg/L (OECD 201)	0.5 mg/L (Algal growth inhibition test according to UBA 1984)
Toxicity to microorganisms [EC50]	200.4 mg/L (OECD 209)	950 mg/L (OECD 209)

* Data were taken from Phenol, 4-nonyl-,branched (CAS 84852-15-3) dossier published on the ECHA data base

 

Several soil - simulation studies with 4-nonylphenol are available in the literature. However, only one focused on different branched nonylphenol isomers. Shan et al. (2011) studied the degradation of five p-nonylphenol (4-NP) isomers including four branched (4-NP38, 4-NP65, 4-NP111, and 4-NP112) and one linear (4-NP1) isomers in a rice paddy soil using 14C- and 13C-ring-labelled nonylphenol. Degradation followed availability-adjusted first-order kinetics with the decreasing order of half-life 4-NP111 (10.3 days) > 4-NP112 (8.4 days) > 4-NP65 (5.8 days) > 4-NP38 (2.1 days) > 4-NP1 (1.4 days). One metabolite of 4-NP111 with less polarity than the parent compound occurred rapidly and remained stable in the soil. At the end of incubation (58 days), bound residues of 4-NP111 amounted to 54% of the initially applied radioactivity and resided almost exclusively in the humin fraction of soil organic matter, in which chemically humin-bound residues increased over incubation.

In conclusion, branched nonylphenol is mineralized slowly but integrated into organic matter rapidly in soil. Based on the reasons given above this conclusion is also considered to be true for Benzaldehyde, 2-hydroxy-5 -dodecyl, oxime, branched (CAS 1233873-37-4).