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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

All constituents of Ethanone, 1-(2-hydroxy-5-nonylphenyl)-, oxime, branched do not bioaccumulate in aquatic or sediment organisms.

Key value for chemical safety assessment

BCF (aquatic species):
159 dimensionless

Additional information

Since no study assessing the bioaccumulation potential of Ethanone, 1-(2-hydroxy-5-nonylphenyl)-, oxime, branched (CAS 244235-47-0) is available, in accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5 Grouping of substances, a read-across approach was applied. To assess the bioaccumulation potential of the main component (C9 Ketoxime) 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 main component of the target substance is the lack of a methyl group at the oxime carbon of the source substance. 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 (see table below).

In addition, available experimental data and QSAR calculations with the minor constituents branched nonylphenol (CAS 84852-15-3), phenol (CAS 108-95-2) and 2-ethylhexanoic acid (CAS 149-57-5) were used to be able to adequately conclude on the bioaccumulation potential of the whole UVCB target substance.

Substance

Ethanone, 1-(2-hydroxy-5-nonylphenyl)-, oxime, branched

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

CAS number

244235-47-0

174333-80-3

Structure

see attachment

see attachment

Molecular formula

C17H27NO2

C16O2NH25

Molecular weight

~ 277 g/mole

~ 263 g/mole

PC parameter

 

 

Water solubility

 > 0.02 < 0.1 mg/L (EU method A.6)

0.4 mg/L (EU method A.6)

Partition coefficient

> 5.7 (EU method A.8)

5.5 (EU method A.8)

Vapour pressure

< 1.5 Pa at 20 °C (OECD 104)

0.37 Pa at 20 °C (OECD 104)

Environmental fate

 

 

Biodegradability

1 % in 28 days (BODIS)

0 % in 28 days (OECD 302c)

Adsorption [log KOC]

3.9 (OECD 121)

3.7 (OECD 121)

Hydrolysis

not relevant due to very low water solubility

Ecotoxicology

 

 

Short-term toxicity to fish

[96h-LC50]

0.46 mg/L (EU method C.1)

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]

2.8 mg/L (OECD 211)

0.189 mg/L (OECD 211)

Short-term toxicity to algae

[72h-EC50]

760 mg/L (OECD 201)

36.3 mg/L (OECD 201)

Long-term toxicity to algae

[72h-NOEC]

472 mg/L (OECD 201)

14.9 mg/L (OECD 201)

Toxicity to microorganisms

[3h-EC10]

260.1mg/L (OECD 209)

200.4 mg/L (OECD 209)

The bioaccumulation study with the source substance Benzaldehyde, 2-hydroxy-5-nonyl, oxime, branched was performed according to GLP and OECD guideline 305 using Oncorhynchus mykiss as test organism. The fish were exposed for 4 weeks followed by a three week depuration period. Test substance concentrations of 7 and 35 µg/L were used. Based on whole body weight and total fat and assuming steady state, for both concentrations a plateau was reached after 6 days. The BCF is determined to be 138 and 159, respectively. While one fish died, neither abnormal behaviour nor abnormal growth was observed. Depuration was achieved after 4 and 8 days, respectively. Thus it can be concluded that the bioaccumulation potential of the main component is low. This conclusion is supported by results of numerous publications showing similar low BCF values (167-740) of branched nonylphenol (CAS 84852-15-3) for different taxa (see respective dossier at ECHA database). In addition, the two minor constituents phenol (CAS 108-95-2) and 2-ethylhexanoic acid (CAS 149-57-5) do also not bioaccumulate as shown in available test data or valid QSAR calculations.

Based on the low measured BCF values (which is much lower than the threshold value of 2000 listed in ECHAs Guidance on information requirement and chemical safety assessment Chapter R.11) and the depuration rates measured for a suitable source substance as well as the constituents of the substance to be registered, it can be concluded that the whole UVCB substance does not accumulate remarkably in fish.