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PBT assessment

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PBT assessment: overall result

Reference
Name:
2-methoxynaphthalene
Type of composition:
boundary composition of the substance
State / form:
other: Solid
Reference substance:
2-methoxynaphthalene
PBT status:
the substance is not PBT / vPvB
Justification:

Classification of 2-methoxynaphthalene for effects in the environment:

 

The chemical2-methoxynaphthalene(CAS no. 93-04-9) isused as flavour and fragrance agent.The aim was to assess whether the PBT criterion within Annex XIII was fulfilled for2-methoxynaphthalene. 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

On the basis of various experimental results of biodegradation studies for the test chemical2-methoxynaphthalene(CAS no. 93-04-9), it indicates thatchemical2-methoxynaphthalenewas expected to be inherently biodegradable in water and thus likely to be not persistent (not P) 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 79.9%). In soil,2-methoxynaphthalenewas expected to have slow mobility based upon a Log KOC value of 3.280±0.001 dimensionless at 25°C as per OECD TG 121. 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 in water compartment, the half-life (26 days at 12°C as per OECD TG 309) in water 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 1% i.e reported as 0.673% when estimated by EPI Suite version 4.1).

 

Hence it has been concluded thatchemical2-methoxynaphthaleneis 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 ranges from 90 to 293, respectively and theoctanol water partition coefficient of the test chemical ranges was determined to be 3.318 ± 0.003 at 25°C as per OECD TG 117 and 3.47, 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 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 data for fish, invertebrates and algae for the substance2-methoxynaphthaleneindicates the LC50/EC50 value to be in the range 4.04 mg/l to < 50 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 in ‘Aquatic chronic category 2’ as per the CLP regulation.

 

On the basis ofthelong term eco-toxicity data for fish, the NOEC value was evaluated to be 1.09 mg/l and based on the experimental study of long term eco-toxicity data for aq. Invertebrates, the 21 d EC50 value was determined to be 5.89 mg/l, respectively. 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 does not fulfil the P, B and T criterion and has therefore not been classified as a PBT compound within Annex XIII.