5-(C11-C12 alkyl, branched)-2-hydroxy-benzaldehyde oxime

Endpoint summary

Additional information

Short-term toxicity

One GLP guideline study evaluating the toxicity of 5-[C11-12 (branched) alkyl]-2-hydroxybenzaldehyde oxime to algae is available showing low toxicity of the substance (72h-EC50 = 498.32 mg/L, 72h-EC10 = 101.2 mg/L). Since short-term toxicity tests with fish and invertebrates are not 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 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. Details are given in the analogue justification document attached to chapter 13.

 An 96h-LC50 of 1.1 mg/L for Danio rerio and an 48h-EL50 value of 2.7 mg/L for Daphnia magna indicate that the test substance is acutely toxic to aquatic organisms and that fish are more sensitive than algae and invertebrates. The toxicity of the test substance to microorganisms was also assessed based on available data for Benzaldehyde, 2-hydroxy-5-nonyl, oxime, branched (CAS 174333-80-3) in a read across approach. In a study according to OECD guideline 209 a 3h-EC50 is determined to be > 1000 mg/L, while the respective EC10 is determined to be 200.4 mg/L. Based on this result it can be concluded that the inhibition of the degradation activity of activated sludge is not anticipated when introduced to biological treatment plants in appropriate low concentrations.

 

Long-term toxicity

A long-term test evaluating the toxicity of 5-[C11-12 (branched) alkyl]-2-hydroxybenzaldehyde oxime to algae is available. Since no study assessing the long-term toxicity of 5-[C11-12 (branched) alkyl]-2-hydroxybenzaldehyde oxime to fish and invertebrates are available, in accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5 Grouping of substances, read-across to Benzaldehyde, 2-hydroxy-5-nonyl, oxime, branched (for long-term toxicity to invertebrates) and 4-nonylphenol (for long-term toxicity to fish) were conducted. 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 similar mode of action but a higher aquatic toxicity compared to 5-(C11-C12 alkyl, branched)-2-hydroxy-benzaldehyde. Therefore, using data from 4-nonylphenol to assess the intrinsic hazard of 5-(C11-C12 alkyl, branched)-2-hydroxy-benzaldehyde is considered to be a conservative and sufficiently protective approach (worst case scenario).

A 21d-NOEC of 0.189 mg/L was observed for Daphnia magna tested with Benzaldehyde, 2-hydroxy-5-nonyl, oxime, branched (CAS 174333-80-3) in a study performed according to OECD guideline 211 and GLP. The long-term toxicity to fish was assessed based on results of a test studying the chronic toxicity of 4-nonylphenol to early life stage of rainbow trout (Oncorhynchus mykiss) under flow through conditions (Spehar et al. 2010). The study was performed according to ASTM guideline E 1241-05 over an exposure time of 91 days. 100 fertilized eggs per test concentration were exposed to measured concentrations of 6.0, 10.3, 23.1, 53.0 and 114 µg/L 4-nonylphenol. The test system was maintained at ~ 11 ºC and a pH of 6.97. Mean percent hatch of any test concentration was not significantly different from controls. Time to hatch was 39 ± 5 days with swim-up at approximately at day 45. The most sensitive end point was growth. The 91-day NOEC value, based on sublethal effects (growth measured by mean standard length, wet weight and dry weight) is determined to be 6.0 µg/L. Based on the reasons given above this value is considered to be sufficiently conservative to be used for the hazard assessment of

5-[C11-12 (branched) alkyl]-2-hydroxybenzaldehyde oxime.

The tests used for assessing the long-term toxicity of 5-[C11-12 (branched) alkyl]-2-hydroxybenzaldehyde oxime to aquatic organisms indicate that the test substance is very toxic to aquatic organisms based on long-term exposure and that fish are more sensitive than algae and invertebrates.

 

Endocrine mode of action

No study is available focusing on potential effects of 5-(C11-C12 alkyl, branched)-2-hydroxy-benzaldehyde based on an endocrine mode of action. However, various studies are available assuming endocrine disrupting effects of 4-nonylphenol in fish and invertebrates (see ECHA 2012, SVHC Support Document). In general, effects occur in the range of 1 to 10 µg/L. Thus, the PNEC value derived for freshwater and marine water on the basis of a long-term toxicity fish test with 4-nonylphenol is considered to be sufficiently low to also cover effects related to this specific mode of action.