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Classification & Labelling & PBT assessment

PBT assessment

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Administrative data

PBT assessment: overall result

PBT status:
the substance is not PBT / vPvB

Classification of Tetra-n-butylammonium hydrogen sulfate for effects in the environment:


The chemical Tetra-n-butylammonium hydrogen sulfate (CAS no. 32503-27-8) is used for multiple applications such as a lab reagent for analysis and It serves as a phase-transfer catalyst, surface-active agent, solvent, intermediate, active ingredient for conditioners, antistatic agent, detergent sanitizers, softener for textiles and paper products, emulsifying agents and pigment dispersers. The aim was to assess whether the PBT criterion within Annex XIII was fulfilled for Tetra-n-butylammonium hydrogen sulfate. 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:


Environmental fate

According to the fugacity model levels III, the most likely environmental fate for this test chemical is soil (i.e.estimated to 80%). In soil, the substance was expected to have low mobility based upon a Log KOC of 3.04. The half-life in sediment and soil (17.33 days estimated by EPI suite) indicates that the chemical is not persistent in soil and the exposure risk to soil dwelling animals is moderate to low.


If released in to the environment, 17.8 % and 2.17% of the chemical will partition into water and sediment respectively, according to the Mackay fugacity model level III in EPI suite version 4.1 (2016). However, the half-life in water and sediment (8.66 days and 71.916 days, respectively estimated by EPI suite) indicates that the exposure risk to aquatic and sediment dwelling animals is low.


Hence it has been concluded that Tetra-n-butylammonium hydrogen sulfate is not persistent 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 (EPI Suite, 2016) was determined to 70.79 L/kg wet wt. and the estimated octanol-water partition coefficient (Log Kow) is reported as 0.96. 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:



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 estimation for fish, invertebrates and algae for the substance indicates the LC50/EC50 value to be in the range 19.804 - >100 mg/L. These value suggest that the substance is likely to be hazardous to Aquatic organisms at environmentally relevant concentrations and can be considered to be classified in Aquatic chronic category 3 as per the CLP regulation.

There are no available long-term toxicity evaluations for Tetra-n-butylammonium hydrogen sulfate. By speculation, long-term NOEC for aquatic organisms were not expected for Tetra-n-butylammonium hydrogen sulfate at concentration below 0.01 mg/L based on the data mentioned above since all the short-term data are above 10 mg/L.

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



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.