N-(2-aminoethyl)-N'-[3-(trimethoxysilyl)propyl]ethylenediamine

PBT assessment

PBT assessment: overall result

PBT status:

the substance is not PBT / vPvB

Justification:

The PBT Assessment for the substance is based on the criteria set out in the “Guidance on information requirements and chemical safety assessment, Chapter R.11: PBT Assessment”.

Persistence Assessment

N-(2-aminoethyl)-N'-[3-(trimethoxysilyl)propyl]ethylenediamine (CAS 35141-30-1) hydrolyses rapidly in water (half-life = 4.3 h at 20-25 °C and pH 7) to N-(2-aminoethyl)-N'-[3-(trihydroxysilyl)propyl]ethylenediamine and methanol. The hydrolysis is expected to occur during a standard biodegradation test. According to the Guidance on Information Requirements and Chemical Safety Assessment Chapter R.11: PBT/vPvB assessment, hydrolysis is considered as primary degradation and the stable degradation products formed, should be considered for PBT assessment (ECHA, 2017).

Since no data on the biodegradation of the substance were available, good quality data from the analogues substance N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (CAS 1760-24-3), were read across. After 28 d the percentage biodegradation of the source substance was 39% (based on DOC). Therefore, the read across substance is considered as not rapidly biodegradable. 

Based on the results of the analogue substance, N-(2-aminoethyl)-N'-[3-(trimethoxysilyl)propyl]ethylenediamine (CAS 35141-30-1) and its silanol hydrolysis product are considered not rapidly biodegradable. The other hydrolysis product methanol is known to be readily biodegradable (OECD, 2004).

Therefore, the substance is considered to meet the criteria for persistence (P and vP). 

 

Bioaccumulation Assessment

The parent substance N-(2-aminoethyl)-N'-[3-(trimethoxysilyl)propyl]ethylenediamine (CAS 35141-30-1) degrades rapidly in water via hydrolysis (< 12 h at pH 4-7) resulting into N-(2-aminoethyl)-N'-[3-(trihydroxysilyl)propyl]ethylenediamine and methanol. Therefore the hydrolysis products are more relevant concerning bioaccumulation potential than the parent substance. The silanol hydrolysis product bears a very low log Kow value of -3.9. The other hydrolysis product, methanol is also negligible with regard to bioaccumulation (OECD 2004).

Based on these information, N-(2-aminoethyl)-N'-[3-(trimethoxysilyl)propyl]ethylenediamine (CAS 35141-30-1) does not meet the criteria for bioaccumulation and is not B and not vB.

 

Toxicity Assessment

Studies are available, in which the short term toxicity of the read across substance N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (CAS 1760-24-3) towards aquatic organisms of three different trophic levels has been assessed. The EC10/NOEC value was determined for algae and was > 0.01 mg/L. Furthermore, neither the substance nor its hydrolysis products are classified for specific target organ toxicity, carcinogenicity, mutagenicity and is not toxic for reproduction and development towards mammals. The criteria for “T” are therefore not met. 

In conclusion N-(2-aminoethyl)-N'-[3-(trimethoxysilyl)propyl]ethylenediamine (CAS 35141-30 -1) is not PBT/vPvB.

Reference:

OECD (2004): SIDS Initial Assessment Report for SIAM 19, Berlin, Germany, 18-20 October 2004, Methanol, CAS 67-56-1.