Ethyl 2-naphthyl ether

PBT assessment

PBT assessment: overall result

PBT status:

the substance is not PBT / vPvB

Justification:

Classification of Ethyl 2-naphthyl ether for effects in the environment:

 

The chemical Ethyl 2-naphthyl ether (CAS no. 93-18-5) is used as a flavour and fragrance agent. It is used for the deployment of detergent and soap flavour, and can be used as sweetener & floral agent. It is also used in jasmine, orange, blossom, cologne-based, etc. for the soap. The aim was to assess whether the PBT criterion within Annex XIII was fulfilled for Ethyl 2-naphthyl ether. 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

42-days Closed Bottle test following the OECD guideline 301 D to determine the ready biodegradability of the test item Ethyl 2-naphthyl ether (CAS No.93-18-5). The study was performed at a temperature of 20°C. The test system included control, test item and reference item. Polyseed were used for this study. 1 polyseed capsule were added in 500 ml D.I water and then stirred for 1 hour for proper mixing and functioning of inoculum. This gave the bacterial count as 10E7 to 10E8 CFU/ml. At the regular interval microbial plating was also performed on agar to confirm the vitality and CFU count of microorganism. The concentration of test and reference item (Sodium Benzoate) chosen for both the study was 4 mg/L, while that of inoculum was 32 ml/l. OECD mineral medium was used for the study. ThOD (Theoretical oxygen demand) of test and reference item was determined by calculation. % degradation was calculated using the values of BOD and ThOD for test item and reference item. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was determined to be 75.3%. Degradation of Sodium Benzoate exceeds 46.38 % on 7 days & 61.44 % on 14th day. The activity of the inoculum was thus verified and the test can be considered as valid. The BOD42 value of test chemical Ethyl 2-naphthyl ether was observed to be 0.9 mgO2/mg. ThOD was calculated as 2.69 mgO2/mg. Accordingly, the % degradation of the test item after 42 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 33.45%. Based on the results, the test item, under the test conditions, was considered to be primary inherently biodegradable in nature.

 

Thus, based on the above available information, it has been concluded Ethyl 2-naphthyl ether is likely to be not persistent 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 80.6%). In soil, Ethyl 2-naphthyl ether was expected to have negligible to slow mobility based upon a Log KOC value 3.4906. 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, 18.2% 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 2% i.e reported as 1.08% when estimated by EPI Suite version 4.1).

 

Hence it has been concluded that chemical Ethyl 2-naphthyl ether 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:

 

Theestimated BCF value from authoritative database was determined to be in the range from 136.6 to 538, respectively and theoctanol water partition coefficient of the test chemical ranges was determined to be 3.74, 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

As per Column 2 (Annex VIII) of the REACH regulation,testing for this end point is considered scientifically unjustified since there are mitigating factors indicating that aquatic toxicity is unlikely to occur as the substance is highly insoluble in water (solubility: < 0.01 mg/L at 30° C) and on the basis of all the available short-term eco-toxicity information for invertebrates for the substance indicates the LC50/EC50 value was determined to be 3.9 mg/L. Since, the test chemicalEthyl 2-naphthyl etheris highly insoluble in water & as the stock solutions of the test chemical was prepared in acetone, the EC50 value (3.9 mg/l) cannot be used to classify the test chemical for aquatic toxicity. The chemical Ethyl 2-naphthyl ether was therefore not considered as hazardous to aquatic environments as per the criteria set out in Annex XIII.

 

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.