Registration Dossier
Registration Dossier
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EC number: 201-073-3 | CAS number: 77-98-5
Toxicity to microorganisms
Administrative data
Link to relevant study record(s)
Description of key information
35%TEAH was not toxic to the inoculum in a ready biodegradability test carried out according to OECD301B and GLP (Desmares-Koopmans, 2014). The corresponding TEAH concentration was 19 mg/L. In accordance with IR/CSR guidance R.10 paragraph 10.4.2, this can be used as a NOEC value for STP microorganisms.
Key value for chemical safety assessment
- EC10 or NOEC for microorganisms:
- 19 mg/L
Additional information
35%TEAH was not toxic to the inoculum in a ready biodegradability test carried out according to OECD301B and GLP (Desmares-Koopmans, 2014). The corresponding TEAH concentration was 19 mg/L. In accordance with IR/CSR guidance R.10, paragraph 10.4.2 this can be used as a NOEC value for STP microorganisms.
This is supported by a study with the structurally similar substance TMAH pentahydrate (see read-across justification in IUCLID section 13). The toxicity of TMAH pentahydrate to microorganisms was determined in a 3 h activated sludge respiration inhibition study carried out according to OECD guideline No. 209 and GLP principles (Desmares-Koopmans, 2013).
In a combined limit/range-finding test, microorganisms in activated sludge were exposed to the test substance at a concentration of 10, 100 and 1000 mg/L under static conditions.Under test conditions TMAH pentahydrate significantly inhibited the respiration rate of waste water (activated sludge) at 1000 mg/L. However, the EC50 exceeded the highest test concentration of 1000 mg/L and no NOEC could be determined.- Based on the molecular weight of TMAH pentahydrate (181.2 g/mol) and TMAH (91.15 g/mol) it can be calculated that the EC50 value of > 1000 mg/L test material (TMAOH pentahydrate) corresponds with > 503 mg/L TMAH.
All criteria for acceptability of the test were met and this study was considered to be valid. The present toxicity study is classified as reliable without restrictions according to the OECD guideline No. 209.
The NOEC that was derived from the OECD301B study (Desmares-Koopman, 2014) was used as a worst case approach as this value leads to the lowest PNEC.
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