Divinylbenzene

PBT assessment

PBT assessment: overall result

Reference

Name:

divinylbenzene

Type of composition:

legal entity composition of the substance

Reference substance:

divinylbenzene

Reference substance:

divinylbenzene

Reference substance:

divinylbenzene

Reference substance:

divinylbenzene

PBT status:

the substance is not PBT / vPvB

Justification:

Classification of 1,2-di(ethenyl)benzenefor effects in the environment:

 

The chemical 1,2-di(ethenyl)benzene (CAS no. 1321-74-0) is used as an insecticide stabilizer in an ion exchange resin, as a cross-linking agent in water purification, as a sustained release agent and as a dental filling component. It is used as a co-monomer in the production of ion exchange beads and gel chromatography. Also used as a monomer in the production of synthetic rubber, drying oils, polyester resin and casting resins etc.. The aim was to assess whether the PBT criterion within Annex XIII was fulfilled for 1,2-di(ethenyl)benzene. 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 fulfils the P criterion within Annex XIII based on the assessment that here follows:

 

Biotic degradation

In an experimental key study from authoritative database and secondary source, biodegradation experiment was conducted for 28 days for evaluating the percentage biodegradability of test substance 1,2-di(ethenyl)benzene (CAS no. 1321-74-0). The study was performed according to OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I) under aerobic conditions. Activated sludge was used as a test inoculums for the study. Concentration of inoculum i.e, sludge used was 30 mg/l and initial test substance conc. used in the study was 100 mg/l, respectively. The percentage degradation of test substance 1,2-di(ethenyl)benzene was determined to be 0% by BOD parameter in 28 days. Thus, based on percentage degradation,1,2-di(ethenyl)benzene is considered to be not readily biodegradable in nature.

 

In a prediction using the Estimation Programs Interface Suite (2018), the biodegradation potential of the test compound  1,2-di(ethenyl)benzene (CAS no. 1321 -74 -0) 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 1,2-di(ethenyl)benzene is expected to be not readily biodegradable.

                                                                 

Experimental results from the read across substances also indicate that they are not readily biodegradable.

 

Hence, it has been concluded that chemical 1,2-di(ethenyl)benzene is likely to be persistent (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 authoritative databases was determined to beranges from 148.7 to 444, respectively and the octanol water partition coefficient of the test chemical ranges from 3.6 to 3.8, 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, invertebrates and algae for the substance1,2-di(ethenyl)benzeneindicates the LC50/EC50 value to be in the range 1.7 to 4.2 mg/L, respectively and on the basis of long term eco-toxicity data for fish and aq. invertebrates, the NOEC value was determined to be ranges from 0.35 to 0.46 mg/l, respectively. 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 ‘Aquatic Chronic Category 2’ as per the CLP regulation.

 

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 fulfils the P criterion but does not fulfil the B and T criterion and has therefore not been classified as a PBT compound within Annex XIII.