Reaction mass of tridecanal and 2-methyldodecanal and pentadecanal and 2-methyltetradecanal

Toxicity to microorganisms

Description of key information

NOEC (n/i-C13 -C15 –aldehydes; OECD 310; toxicity control): 23.6 mg/L (Harlan, 2011)

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

23.6 mg/L

Additional information

n/i-C13 -C15 –aldehydes (23.6 mg/L), a mixture of n/iso C13 and C15 aldehydes, was tested for ready biodegradation in an OECD TG 310 assay under GLP conditions (Harlan, 2011) . In the toxicity control for inoculum toxicity, the biodegradation of the reference item 1-octanol (25.4 mg/L in the test) was not inhibited by the n/i-C13 -C15 –aldehydes at 23.6 mg/L, i.e. there was no toxicity to microorganisms at this concentration. According to the ECHA Guidance Document on Information Requirements and Chemical Safety Assessment, parts R.7b and R.10, this concentration can be considered as a NOEC. Consequently, the NOEC for microorganism toxicity equals 23.6 mg/L, and no further tests on STP microorganism toxicity have to be conducted.

 

This result is supported by an earlier (not reliable) study on ready biodegradability of n/i-C13 -C15 –aldehydes according to OECD TG 301F (Hoechst, 1995). In the toxicity control (n/i-C13 -C15 –aldehydes at nominal 1002 mg/L), the biodegradation of the reference substance sodium benzoate was 64% within 14 days. Thus, n/i-C13 -C15 –aldehydes were not toxic to microorganisms and, according to these data, 1002 mg/L would correspond to the NOEC for STP microorganisms toxicity.

 

For the assessment of the PNECstp, the NOEC of the OECD 310 study (Harlan, 2011) was used since this value is closer to the water solubility limit of n/i-C13 -C15 –aldehydes (2 mg/L @ 20 °C; OXEA, 2009).