Registration Dossier

Diss Factsheets

Administrative data

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:
no hazard identified

Marine water

Hazard assessment conclusion:
no hazard identified

STP

Hazard assessment conclusion:
no hazard identified

Sediment (freshwater)

Hazard assessment conclusion:
no hazard identified

Sediment (marine water)

Hazard assessment conclusion:
no hazard identified

Hazard for air

Air

Hazard assessment conclusion:
no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:
no hazard identified

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:
no potential for bioaccumulation

Additional information

Conclusion on classification

KEY PARAMETERS FOR CLASSIFICATION


The registered substance N-[3-(Trimethoxysilyl)propyl]-1-butanamine (CAS No. 31024-56-3) is expected to hydrolyse rapidly in contact with water (DT50 = 4.0 h at pH 7 and 20-25 °C, QSAR) to 3-(N-butylamino)propylsilanetriol and methanol. REACH guidance R.16 states that “for substances where hydrolytic DT50 is less than 12 h, environmental effects are likely to be attributed to the hydrolysis product rather than to the parent itself” (ECHA, 2016). The environmental hazard and risk assessment is therefore based on the silanol hydrolysis product, i.e. 3-(N-butylamino)propylsilanetriol. The other, alcohol hydrolysis product, methanol, is not expected to affect the environmental hazard profile of the parent substance (OECD SIDS, 2004).


 


Abiotic degradation - Hydrolysis


DT50 = 4.0 h at pH 7 and 20-25 °C (QSAR)


 


Biodegradation in water


Parent: Not readily biodegradable (24.7% in 28 d, OECD 301 B)


Silanol HP: Not readily biodegradable (24.7% in 28 d, OECD 301 B)


 


Bioaccumulation


log D (parent, pH 7) = -1.47 (20 °C, QSAR)


log D (silanol hydrolysis product, pH 7) = -3.91 (20°C, QSAR)


 


Aquatic acute toxicity


Fish


LC50 (96 h) > 100 mg/L (nominal, Danio rerio, OECD 203, read across from CAS No. 227085-51-0)


LC50 (96 h) > 50 mg/L (nominal, Oncorhynchus mykiss, OECD 203, supporting study)


 


Aquatic invertebrates


EC50 (48 h) > 100 mg/L (nominal, Daphnia magna, OECD 202, read across from CAS No. 227085-51-0)


EC50 (48 h) > 25 mg/L (nominal, Daphnia magna, OECD 202, supporting study)


 


Aquatic algae


ErC50 (72 h) > 100 mg/L (nominal, Scenedesmus subspicatus, OECD 201, read across from CAS No. 227085-51-0)


ErC50 (72 h) > 1 mg/L (nominal, Pseudokirchneriella subcapitata, OECD 201, supporting study)


 


Aquatic chronic toxicity


Aquatic algae


NOEC (72 h) = 22 mg/L (nominal, Scenedesmus subspicatus, OECD 201, read across from CAS No. 227085-51-0)


NOEC (72 h) >= 1 mg/L (nominal, Pseudokirchneriella subcapitata, OECD 201, supporting study)


 


Classification according to CLP


N-[3-(Trimethoxysilyl)propyl]-1-butanamine (CAS No. 31024-56-3) is expected to hydrolyse rapidly under environmental conditions (DT50 = 4.0 h at pH 7 and 20 °C) to form the silanol hydrolysis product 3-(N-butylamino)propylsilanetriol and methanol. The registered compound and its silanol hydrolysis product are not considered to be readily biodegradable, while the alcohol hydrolysis product methanol is considered to be readily biodegradable (OECD SIDS, 2004). Acute aquatic toxicity data are available for all three trophic levels (fish, aquatic invertebrates, algae) on the registered compound. The L(E)C50 effect values are > 1 mg/L in all three trophic levels. However, the tested concentrations were well below the predicted solubility of the substance (1.3E+04 mg/L) and therefore do not provide an accurate representation of the likely toxicity of the substance. Thus, data was read across from the structurally analogue substance, N-ethyl-3-trimethoxysilyl-2-methylpropanamine (CAS No. 227085-51-0). The source substance is also expected to hydrolyse rapidly in the aquatic environment (DT50 = 4.7 h at pH 7 and 20-25 °C, QSAR) to form a structurally similar silanol hydrolysis product, N-ethyl-3-trihydroxysilyl-2-methylpropanamine, and the common alcohol hydrolysis product methanol. Short-term aquatic data is available for all three trophic levels. No short-term toxicity effects up to the highest concentrations tested were observed in all three organism groups (EC/LC50 > 100 mg/L). Due to the rapid hydrolysis of the parent source compound and the duration of the acute aquatic toxicity tests (48 to 96 h), the test organisms were likely predominantly exposed to the hydrolysis products of the source compound. Because the alcohol hydrolysis product methanol is known for its low environmental hazard profile with effect values well above the herein tested concentrations (OECD SIDS, 2004), methanol can be disregarded in the overall environmental hazard assessment. Therefore, N-[3-(Trimethoxysilyl)propyl]-1-butanamine (CAS No. 31024-56-3) and its silanol hydrolysis product 3-(N-butylamino)propylsilanetriol do not need to be classified and labeled according to the consolidated version of Regulation (EC) No 1272/2008 and further amendments (ATPs).