Diisopropyl adipate

PBT assessment

PBT assessment: overall result

Reference

Name:

diisopropyl adipate

Type of composition:

legal entity composition of the substance

State / form:

liquid

Reference substance:

diisopropyl adipate

PBT status:

the substance is not PBT / vPvB

Justification:

Classification of Diisopropyl adipate for effects in the environment:

 

The chemical Diisopropyl adipate (CAS no. 6938-94-9) is used as a flavouring agent.The aim was to assess whether the PBT criterion within Annex XIII was fulfilled for Diisopropyl adipate.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

The objective of the study was to measure Biochemical Oxygen Demand of test chemical over a 5-day period by closed bottle test and thereby calculating percentage degradation on the basis of its theoretical oxygen demand (ThOD). The test contained a control group, a reference group, and a test substance group. The solution of the test substance having a concentration of 2 mg/L in mineral medium, was inoculated with a 0.5 ml/L of surface water (used as inoculum) and kept in completely full closed bottles in BOD incubator at constant temperature of 20 ± 2°C. DO determination on the 0thand 5thday of the experiment was done using Winkler Azide Titration method. The amount of oxygen taken up by the microbial population during biodegradation of the test substance was corrected for uptake by the blank inoculum and BOD5was calculated accordingly. The biochemical degradation of the test substance is expressed as a percentage of ThOD. ThOD, BOD5and % Degradation of the test substance was determined to be 41.27% in 5 days. Thus based on these results it can be concluded that test chemical is readily biodegradable.

 

In a prediction done by using the Estimation Programs Interface Suite (2018), the biodegradation potential of the test chemical in the presence of mixed populations of environmental microorganisms was estimated. The biodegradability of the substance was calculated using seven different models such as Linear Model, Non-Linear Model, Ultimate Biodegradation Timeframe, Primary Biodegradation Timeframe, MITI Linear Model, MITI Non-Linear Model and Anaerobic Model (called as Biowin 1-7, respectively) of the BIOWIN v4.10 software. The results indicate that chemical is expected to be readily biodegradable.

 

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

 

Thus, based on the available information, it indicates that chemical Diisopropyl adipate can be considered to be readily biodegradable in water and thus likely to be not persistent (not P) in nature.

 

Environmental fate

According to the fugacity model levels III, the most likely environmental fate for this test chemical is soil (i.e.estimated to 69.7%). In soil,Diisopropyl adipatewas expected to have negligible to slow mobility based upon a Log KOC value of 3.542. The half-life in soil (30 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, 28.3% of the chemical will partition into water according to the Mackay fugacity model level III in EPI suite version 4.1 (2017). However, the half-life (15 days estimated by EPI suite) indicates that the chemical is not persistent in water and the exposure risk to aquatic animals is moderate to low.

 

Moreover, its persistent characteristic is only observed in the sediment compartment but Fugacity modelling shows that sediment is not an important environmental fate (less than 1% i.e. reported as 0.137% when estimated by EPI Suite version 4.1).

 

Hence it has been concluded that Diisopropyl adipate 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 from authoritative databases was determined to be 59 to 77.4, respectivelyand the octanol water partition coefficient of the test chemical was determined to be 3.389, 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 fish and algae for the substanceDiisopropyl adipateindicates the LC50/EC50 value to be in the range 11 mg/l to > 15.93 mg/L, respectively and on the basis ofthe various experimental studies of shortterm eco-toxicity data for aq. invertebratesof the structurally and functionally similar read across chemical (including the biodegradability of read across chemical) and applying the weight of evidence approach, the EC50 value was determined to be ranges from 46.3 to 151 mg/l, respectively. These value suggest that the substance is likely to be hazardous to aquatic organisms at environmentally relevant concentrations. Since the test chemicalDiisopropyl adipate is readily biodegradable in nature, chemical Diisopropyl adipateis likely to be not hazardous to aquatic organisms at environmentally relevant concentrations and can be considered to be ‘Not classified’ as per the CLP regulation.

 

Based onthe available data oflong term eco-toxicity data for fish, the NOEC value was evaluated to be 0.356 mg/l and on the basis ofthe various experimental studies of longterm eco-toxicity data for aq. invertebratesof the structurally and functionally similar read across chemical (including the biodegradability of read across chemical) and applying the weight of evidence approach, the EC50 value was determined to be ranges from 17.6 to > 46 mg/l and the NOEC value was determined to be ranges from 5.386 to 6.25 mg/l, respectively. 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.