1,1'-(4-chlorobutylidene)bis[4-fluorobenzene]

PBT assessment

PBT assessment: overall result

PBT status:

the substance is not PBT / vPvB

Justification:

Classification of 1,1'-(4-chlorobutylidene)bis[4-fluorobenzene] for effects in the environment:

 

The chemical 1,1'-(4-chlorobutylidene)bis[4-fluorobenzene] (CAS no. 3312-04-7) is used as a laboratory agent as well as an intermediate for pharmaceutical and chemical synthesis. The aim was to assess whether the PBT criterion within Annex XIII was fulfilled for 1,1'-(4-chlorobutylidene)bis[4-fluorobenzene]. 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

Biodegradability of test chemical is predicted using OECD QSAR tool box v.3.3 using log Kow as primary descriptor. The test chemical 1-[4-chloro-1-(4-fluorophenyl)butyl]-4-fluorobenzene (CAS no.3312 -04 -7) showed 0.20 % biodegradation in 28 days by BOD parameter and microorganisms as inoculum. This percent biodegradation value is very less so it is concluded that this test chemical is not readily biodegradable.

 

 In another prediction done by using Estimation Programs Interface Suite (EPI suite, 2017) BIOWIN v4.10. The biodegradation potential of the test chemical   1-[4-chloro-1-(4-fluorophenyl)butyl]-4-fluorobenzene (CAS no. 3312 -04 -7) in the presence of mixed populations of environmental microorganisms. 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-[4-chloro-1-(4-fluorophenyl)butyl]-4-fluorobenzeneis expected to be not readily biodegradable.

 

Experimental results from the similar substances (CAS: 1912-24-9 and 76-83-5) also indicate that they are not readily biodegradable.

 

Environmental fate

According to the fugacity model levels III, the most likely environmental fate for this test chemical is soil (i.e.estimated to 62.5%). In soil, 1,1'-(4-chlorobutylidene)bis[4-fluorobenzene] was expected to have negligible to slow mobility based upon a LogKOC in the range 4.15 – 5.39. Thehalf-life in soil (360 days estimated by EPI suite) indicates that the chemical is persistent in soil and the exposure risk to soil dwelling animals is moderate to high.

 

If released in to the environment, 1.56 % and 35.7 of the chemical will partition into water and sediment respectively, according to the Mackay fugacity model level III in EPI suite version 4.1 (2017). The half-life (180 days in water and 1620.8 days in sediment as estimated by EPI suite) chemical is persistent in both compartments.

 

Although the half-life value in sediment indicate the chemical to be Very persistent (vP), since only predicted data is available for the substance, it has been concluded that 1,1'-(4-chlorobutylidene)bis[4-fluorobenzene] is persistent in nature.

 

 

Bioaccumulation assessment

The tested substance fulfils the B criterion within Annex XIII based on the assessment that here follows:

 

Theestimated BCF value from authoritative database was determined to be in the range 3056 - 10700 and theoctanol water partition coefficient of the test chemical is 5.79 which is more than the threshold of 4.5. If this chemical is released into the aquatic environment, there should be a high 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 estimations for invertebrates and algae for the substance indicates the LC50/EC50 value to be >100 mg/L. These value suggest that the substance is likely to be non-hazardous to Aquatic organisms at environmentally relevant concentrations and can be considered to be not classified as per the CLP regulation.

 

There are no available long-term toxicity evaluations for 1,1'-(4-chlorobutylidene)bis[4-fluorobenzene]. 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 and B criterion but does not fulfil the T criterion and has therefore not been classified as a PBT compound within Annex XIII.