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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 Tetrabutylammonium iodide for effects in the environment:


Tetrabutylammonium iodide (CAS no. 311-28-4) has a wide variety of uses such as intermediate for chemical synthesis, pharma intermediate and as a laboratory chemical. The aim of the PBT assessment was to evaluate whether this chemical fulfils the PBT criterion within Annex XIII. The PBT assessment were based on toxicological information in conjunction with standardized environmental fate- and bioaccumulation 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 77.8%). In soil, Tetrabutylammonium iodide was expected to have rapid mobility based upon an experimental Log KOC of 0.973. The half-life in 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 low.


If released in to the environment, 17.2 % and 5.01% of the chemical will partition into water and sediment according to the Mackay fugacity model level III in EPI suite version 4.1 (2017). However, the half-life (8.66 days in water and 77.91 days in sediemnt estimated by EPI suite) indicates that the substance is not persistent in both compartments.


Hence it has been concluded that Tetrabutylammonium iodide 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 of the substance is 70.79 L/kg (EPI Suite version 4.1, 2017) and the experimental octanol water partition coefficient of the test chemical is 0.868 which is less than the threshold of 4.5. Thus, 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

Most 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 2.8 - >100 mg/L indicating that the substance can be classified as hazardous. 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 2 as per the CLP regulation.


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


The chemical was therefore considered as non-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.