1-(2-hydroxy-5-nonyl(branched)-phenyl)ethanone oxime

Endpoint summary

Additional information

Since no studies assessing the toxicity of Ethanone, 1-(2-hydroxy-5-nonylphenyl)-, oxime, branched (CAS 244235-47-0) to terrestrial organisms are available, in accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5 Grouping of substances, a read-across to 4-nonylphenol was conducted , which is a secondary component and structurally similar to the main component of the substance. The only structural difference between the source substance and the target substance is the lack of a ketoxime group at the phenol ring of the molecule.

The read across is justified due to the following reasons: 

1) The similarity of structure and functional groups and accordingly similar physico-chemical properties result in similar environmental behavior and fate.

2) Based on a profound ecotoxicological data set available for 4-nonylphenol it can be concluded that 4-nonylphenol exhibit a higher aquatic toxicity compared to Ethanone, 1-(2-hydroxy-5-nonylphenyl)-, oxime, branched (see table below). Therefore, using data from nonylphenol to assess the intrinsic hazard of Ethanone, 1-(2-hydroxy-5-nonylphenyl)-, oxime, branched is considered to be a very conservative approach (worst case scenario).

 

Substance	Ethanone, 1-(2-hydroxy-5-nonylphenyl)-, oxime, branched	Phenol, 4-nonyl, branched^*
CAS number	244235-47-0	84852-15-3
Structure	see attachment	see attachment
Molecular formula	C17H27NO2	C15H24O
Molecular weight	~ 277 g/mole	~ 220.35 g/mole
PC parameter
Water solubility	> 0.02 < 1 mg/L (EU method A.6)	5.7 mg/L (ASTM E 1148-02)
Partition coefficient	> 5.7(EU method A.8)	5.4 (OECD 117)
Vapour pressure	< 1.5 Pa at 20 °C (OECD 104)	~1 Pa at 20 °C (ASTM-D 2879)
Environmental fate
Biodegradability	1 % in 28 days (BODIS)	non-adapted inoculum: 0 % in 28 days (OECD 301B)   adapted inoculum: 48.2-62 % in 28 days (OECD 301B)
Adsorption [log KOC]	3.9 (OECD 121)	4.35 - 5.69 (EPA OTS 796.2750)
Hydrolysis	not relevant
Ecotoxicology
Short-term toxicity to fish [96h-LC50]	0.46 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]	9.55 mg/L (OECD 202)	0.08 – 0.14 mg/L (different methods)
Long-term toxicity to aquatic invertebrates [21d-NOEC]	2.8 mg/L (OECD 211)	0.024 - 0.116 mg/L (different methods)
Short-term toxicity to algae [72h-EC50]	760 mg/L(OECD 201)	0.33 - 1.3 mg/L (different methods)
Long-term toxicity to algae [72h-NOEC/EC10]	472 mg/L (OECD 201)	0.5 mg/L (Algal growth inhibition test according to UBA 1984)
Toxicity to microorganisms [EC50]	> 1000 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

One field study is available investigating the effect of increasing 4-nonylphenol (NP) concentrations (0, 10, 30, 90, and 270 mg/kg) in soil microcosms containing a simplified soil community over three sampling dates (28, 56, and 112 days) using the principal response curves method (Domene et al. 2010). The soil community did not change significantly at concentrations below 90 mg/kg, which was selected as the nonobserved effect concentration (NOEC). The highest concentration (270 mg/kg) changed the community significantly after 28 and 56 days, but this effect disappeared after 112 days.

The toxicity of 4-nonylphenol to terrestrial plants was investigated according to OECD guideline 208 using L. perenne and B. rapa as test organisms (Domene et al. 2009). Artificial soil according to OECD was used. Germination and biomass production was recorded after an exposure time of 15 days. Fresh weight was found to be a more sensitive endpoint than germination. However, all 15d-EC50 value showed to be > 1g/kg, which is not considered as toxic according to OECD criteria.

In a long-term toxicity test performed similar to OECD guideline 217, soil microbes were incubated with 100 and 1000 ppm branched 4-nonylphenol (NP) over an exposure time of 40 days (Trocme et al. 1988). An aged mixture of sewage sludge compost and sandstone was used as inoculum. Respiration (CO2 evolution) was recorded daily throughout the test period. Respiration started at the same rate (37 µg C/g organic C per h) in control and treatments. The rates then decreased progressively, indicating depletion of easily mineralizable C and N. CO2 evolution did not differ significantly between the 100 ppm samples and the controls. In contrast, in 1000 ppm samples, CO2 evolution was significantly depressed by the 4th day. Thus, the 40d-NOEC value is determined to be 100 mg/kg dw.

 

Based on the reasons given above these value are considered to be sufficiently conservative to be used for the hazard and risk assessment of Ethanone, 1-(2-hydroxy-5-nonylphenyl)-, oxime, branched (CAS 244235-47-0).