Pentene, 2,4,4-trimethyl-, sulfurized

PBT assessment

PBT assessment: overall result

PBT status:

the substance is not PBT / vPvB

Justification:

Classification of Pentene, 2,4,4-trimethyl-, sulfurized for effects in the environment:

 

The chemical Pentene, 2,4,4-trimethyl-, sulfurized (CAS no. 68515-88-8) is used as a lubricating agent and lubricant additive . The aim was to assess whether the PBT criterion within Annex XIII was fulfilled for Pentene, 2,4,4-trimethyl-, sulfurized. 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 Pentene, 2,4,4-trimethyl-, sulfurized (CAS no. 68515 -88 -8) is predicted using QSAR toolbox version 3.3 with log Kow as the primary descriptor. Test substance undergoes 24.6% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical Pentene, 2,4,4 -trimethyl-, sulfurized was estimated to be not readily biodegradable in water. But as the percentage degradation of the chemical is greater than 20% (i.e reported as 24.6%), chemical can be considered as inherently biodegradable in nature.

 

Estimation Programs Interface Suite (EPI suite, 2017) was run to predict the biodegradation potential of the test compound Pentene, 2,4,4-trimethyl-, sulfurized (CAS no. 68515 -88 -8) 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 Pentene, 2,4,4 -trimethyl-, sulfurized is expected to be not readily biodegradable.

 

Experimental studies for the read across substances (CAS: 1656-63-9 and CAS: 110-01-3) also indicate that the substances can be considered as inherently 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 72.3%). In soil, the substance was expected to have negligible mobility based upon an estimated Log KOC in the range 5-10. The half-life in soil (120 days estimated by EPI suite) indicates that the chemical is persistent and the exposure risk to soil dwelling animals is moderate to high.

 

If released in to the environment, 16.8 % and 10.9 % 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 (60 days and 541.6 days as estimated by EPI suite) indicates that the substance is persistent in both water and sediment.

 

Hence it has been concluded thatPentene, 2,4,4 -trimethyl-, sulfurizedis persistent in nature.  

 

Although the half-life values suggest classification as very persistent (vP), the substance is classified only as persistent (P) since only estimated half-life values are available for the same. Hence it has been concluded thatPentene, 2,4,4 -trimethyl-, sulfurizedis 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 bioaccumulation factor (BCF) was determined to 128.1 L/kg wet wt. 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 fulfils 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 estimation for fish, invertebrates and algae for the substance indicates the LC50/EC50 value to be in the range 0.00049 – 0.33 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 acute category 1 as per the CLP regulation.

 

There are no available long-term toxicity evaluations for butylPentene, 2,4,4 -trimethyl-, sulfurized. By speculation, long-term NOEC for aquatic organisms can be expected forPentene, 2,4,4 -trimethyl-, sulfurizedat concentration below 0.01 mg/L based on the data mentioned above.

 

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