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

Sediment toxicity

Description of key information

NOEC (28d) >= 61.5 mg/kg sediment dw (measured) for reproductive output of marine amphipod Leptocheirus plumulosus (read across)
EC10 (28d) = 203 mg/kg sediment dw (measured) for reproductive output of freshwater midge Chironomus riparius (read across)

Key value for chemical safety assessment

EC10, LC10 or NOEC for freshwater sediment:

203 mg/kg sediment dw

EC10, LC10 or NOEC for marine water sediment:

61.5 mg/kg sediment dw

Additional information

Since no study assessing the toxicity of Benzaldehyde, 2-hydroxy-5-dodecyl, oxime, branched (CAS 1233873-37-4) to sediment organisms is 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 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 Phenol, 4-nonyl-,branched it can be concluded that Phenol, 4-nonyl-,branched exhibit a higher aquatic toxicity compared to Benzaldehyde, 2-hydroxy-5-dodecyl, oxime, branched (see table below). Therefore, using data from Phenol, 4-nonyl-,branched to assess the intrinsic hazard of Benzaldehyde, 2-hydroxy-5-dodecyl, oxime, branched is considered to be a very conservative approach (worst case scenario).

Substance	Benzaldehyde, 2-hydroxy-5 -dodecyl, oxime, branched	Phenol, 4-nonyl, branched^*
CAS number	1233873-37-4	84852-15-3
Structure	see attachment (chapter 6.3)	see attachment (chapter 6.3)
Molecular formula	C19H31N1O2	C15H24O
Molecular weight	~305.46 g/mole	~ 220.35 g/mole
PC parameter
Water solubility	0.3 mg/L (OECD 105)	5.7 mg/L (ASTM E 1148-02)
Partition coefficient	> 5.7 (EU method L3B3 A/63 -73)	5.4 (OECD 117)
Vapour pressure	< 0.39 Pa at 20 °C (estimation based on grain-Watson method)	~1 Pa at 20 °C (ASTM-D 2879)
Environmental fate
Biodegradability	-	non-adapted inoculum: 0 % in 28 days (OECD 301B)   adapted inoculum: 48.2-62 % in 28 days (OECD 301B)
Adsorption [log KOC]	4.4 (OECD 121)	4.35 - 5.69 (EPA OTS 796.2750)
Hydrolysis	not relevant
Ecotoxicology
Short-term toxicity to fish [96h-LC50]	-	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]	-	0.08 – 0.14 mg/L (different methods)
Long-term toxicity to aquatic invertebrates [21d-NOEC]	-	0.024 - 0.116 mg/L (different methods)
Short-term toxicity to algae [72h-EC50]	498.32 mg/L (OECD 201)	0.33 - 1.3 mg/L (different methods)
Long-term toxicity to algae [72h-NOEC/EC10]	101.2 mg/L (OECD 201)	0.5 mg/L (Algal growth inhibition test according to UBA 1984)
Toxicity to microorganisms [EC50]	-	950 mg/L (OECD 209)

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

 

Three long-term toxicity tests are available investigating the effect of 4-nonylphenol on the reproductive output on sediment dwelling organisms:

A 28-day long-term toxicity test of 4-nonylphenol to the marine benthic crustacean, Leptocheirus plumulosus was performed under static conditions (Zulkosky et al. 2002). Crustaceans were exposed to control and 4-nonylphenol at average measured concentrations of 2.1, 4.5, 10.5, 27.2 and 61.5 mg/kg dw. A significant negative correlation (p < 0.034) was observed between 4 -nonylphenol sediment concentration and the number of young produced per female, but it explained only 12% of the variance. Reproductive output in animals exposed to 61.5 mg/g NP was reduced by 40% of control values, but this difference was not statistically significant (p = 0.299). Thus, the 28d-NOEC value is determined to be >= 61.5 mg /gg dw based on reproduction and mortality.

A second study investigated the 28-day long-term toxicity of 4-nonylphenol to Chironomus riparius under semi-static conditions (Bettinetti and Provini 2002). Chironomids were exposed to nonylphenol at nominal concentrations of 270 to 1100 mg/kg sediment dw. The sublethal effects assessed included emergence and egg production. The most sensitive endpoint was emergence. The lowest 28-day EC10 value is determined to be 203 mg/kg dw.

The third study investigated the 28-day long-term toxicity of nonylphenol to Tubifex tubifex under semi-static conditions (Bettinetti and Provini 2002). Tubifex were exposed to 4-nonylphenol at nominal concentrations of 90 - 650 mg/kg sediment dw. The sublethal effects assessed included production of cocoons and young worms per adult. The most sensitive end point was number of young worms per adult. The lowest 28-day EC10 value is determined to be 335 mg/kg dw.

 

Based on the reasons given above this value is considered to be sufficiently conservative to be used for the hazard assessment of Benzaldehyde, 2-hydroxy-5-dodecyl, oxime, branched (CAS 1233873-37-4).

In addition, one field study investigated the effect of Phenol, 4 -nonyl-,branched (CAS 84852-15-3, NP) on sediment dwelling macroinvertebrates is available. Eleven applications of NP, each 48 h apart, were made to the littoral enclosures before recording abundance and emergence of relevant taxonomic groups. The 300 µg/L NP treatment significantly affected most macroinvertebrate groups evaluated, whereas the 100 µg/L NP treatment had possible minor effects on only Naididae and Gastropoda. However, the observed effects on the benthic community were most likely due to NP exposure from the water. Because pore water NP concentrations were low compared to overlying water concentrations, it is unlikely that effects observed on sediment-dwelling organisms (e.g., Chironomini, Tubificidae, and Bivalvia) were significantly influenced by sediment exposures. Therefore, the given NOEC for the benthic community of 23 µg/L is not considered to be relevant for the assessment of the toxicity of Benzaldehyde, 2-hydroxy-5-dodecyl, oxime, branched (CAS 1233873-37-4) to sediment dwelling organisms and thus this effect value was not used for the hazard assessment.