Tetrabutylammonium hydroxide

PBT assessment

PBT assessment: overall result

Reference

Name:

Tetrabutylammonium hydroxide

Type of composition:

boundary composition of the substance

State / form:

liquid

Reference substance:

Tetrabutylammonium hydroxide

PBT status:

the substance is not PBT / vPvB

Justification:

Classification ofTetrabutylammonium hydroxide for effects in the environment:

 

The chemical Tetrabutylammonium hydroxide (CAS no. 2052-49-5) is used as a phase-transfer catalyst. It is also used as a titrant in potentiometric titration. The aim was to assess whether the PBT criterion within Annex XIII was fulfilled forTetrabutylammonium hydroxide.The PBT criterion was herein assessed based on experimental data in conjunction with standardized environmental fate models. Here follows a description of the PBT assessment.

 

Persistence assessment

The tested substance does not fulfil the P criterion within Annex XIII based on the assessment that here follows:

 

Biotic degradation

Biodegradation study was conducted for evaluating the biodegradability of test chemical Tetrabutylammonium hydroxide (CAS no. 2052-49-5) (from handbook). Test chemical was reported to be degraded by Nocardia sp. in wastewaters. Thus, based on this, test chemical is considered to be biodegradable in nature.

 

Experimental results from the read across substances also indicate that they are readily biodegradable.

 

Thus, based on the available information, it indicates thatchemicalTetrabutylammonium hydroxidecan be considered to be readily biodegradable in water and thus likely to be not persistent (not P) in nature.

 

Bioaccumulation assessment

The tested substance does not fulfil the B criterion within Annex XIII based on the assessment that here follows:

 

The estimated BCF value from modelling databases was evaluated to be ranges from 70.79 to 1410, respectivelyand the octanol water partition coefficient of the test chemical was determined to be 1.517 at 25°C as per the OECD TG 117, respectively, which is less than the threshold of 4.5. If this chemical is released into the aquatic environment, there should be a low risk for the chemical to bioaccumulate in fish and food chains.

 

Toxicity assessment

The tested substance does not fulfil the T criterion within Annex XIII based on the assessment that here follows:

 

Mammals

The tested chemical is regarded to be not classified for carcinogenicity, mutagenicity and reprotoxicity, Further, there is no evidence of chronic toxicity, as identified by the classifications STOT (repeated exposure), category 1(oral, dermal, inhalation of gases/vapours, inhalation of dust/mist/fume) or category 2 (oral, dermal, inhalation of gases/vapours, inhalation of dust/mist/fume).

  

Aquatic organisms

All of the available short-term eco-toxicity data for aq. invertebrates and algae for the substanceTetrabutylammonium hydroxide indicates the LC50/EC50 value to be 16.5 mg/l and > 100 mg/l, respectively and on the basis of the various experimental studies of shortterm eco-toxicity data for fishof the structurally and functionally similar read across chemical (including the biodegradability of read across chemical) and applying the weight of evidence approach, the LC50 value was determined to be > 100 mg/l, respectively. The value (EC50 = 16.5 mg/l) suggest that the substance is likely to be hazardous to aquatic organisms at environmentally relevant concentrations. Since the test chemical Tetrabutylammonium hydroxide is readily biodegradable in nature, chemical Tetrabutylammonium hydroxide is likely to be not hazardous to aquatic organisms at environmentally relevant concentrations and hence, considered to be ‘Not classified’ as per the CLP regulation.

 

There are no available long-term toxicity evaluations for chemical Tetrabutylammonium hydroxide. By speculation, long-term NOEC for aquatic organisms were not expected for the substance at concentration below 0.01 mg/L based on the data mentioned above.

 

The chemical was therefore not considered as hazardous to aquatic environments as per the criteria set out in Annex XIII.

 

Conclusion

Based on critical, independent and collective evaluation of information summarized herein, the tested compound does not fulfil the P, B and T criterion and has therefore not been classified as a PBT compound within Annex XIII.