Ethylbenzenesulphonic acid

PBT assessment

PBT assessment: overall result

PBT status:

the substance is not PBT / vPvB

Justification:

Classification of Ethylbenzenesulphonic acid for effects in the environment:

 

The chemicalEthylbenzenesulphonic acid(CAS no. 57352-34-8) is used in chemical synthesis and as a laboratory agent. The aim was to assess whether the PBT criterion within Annex XIII was fulfilled for Ethylbenzenesulphonic acid. 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

Biodegradation study was conducted for 55 days for evaluating the percentage biodegradability of test substance Ethylbenzenesulphonic acid (CAS no. 57352-34-8). Ultraviolet spectroscopic analysis was carried out for studying the biodegradation. Sewage was used as a test inoculums for the study. The sample under study were added to half-gallon fruit jars and diluted to 1 liter to give a 5 ppm (5 mg/l) concentration with the aqueous synthetic medium. In the synthetic system each jar was inoculated with 5 ml of raw sewage. After mixing the contents, the lids were loosened and the samples allowed to incubate on a bench top at room temperature. A control jar containing all ingredients except the sample, was prepared and inoculated in the same manner to serve as a reference medium for the UV analysis. Aliquots were removed at intervals for the UV analyses which were made in 1 cm cells using the solution from the control jar as the reference solution in the spectrophotometer. The wave length region from 300 to 200 mµ was scanned at each sampling period, since these compounds exhibited two usable absorption peaks, one near 220 mµ and another generally near 270 m. The percentage degradation of test substance Ethylbenzenesulphonic acid in the synthetic medium system was determined to be 100% by UV spectrophotometry parameter after 6 days. Thus, based on percentage degradation, Ethylbenzenesulphonic acid is considered to be readily biodegradable in nature.

Other similar experimental studies for the substances also indicate that it is 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 75.4%).Thehalf-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, 24.4% 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 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% when estimated by EPI Suite version 4.1).

 

Hence, it has been concluded thatEthylbenzenesulphonic acidis not persistent (not P) in nature.

 

 

Bioaccumulation: aquatic/sediment

The tested substance does not fulfil the B criterion within Annex XIII based on the assessment that here follows:

 

Theestimated BCF value from authoritative databases was determined to be in the range 1 – 3.162 and theoctanol water partition coefficient of the test chemical is -0.13 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

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 as not classified as per the CLP regulation.

 

There are no long-term toxicity evaluation available for Ethylbenzenesulphonic acid. By speculation, long-term NOEC for aquatic organisms cannot be expected for the substance 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.

 

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