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PBT assessment

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PBT assessment: overall result

Reference
Name:
Reaction mass of 4-(2,6,6-trimethylcyclohex-2-ene-1-yl) -but-3-ene-2-one and 4-(2,6,6-trimethylcyclohex-1-ene-1-yl) -but-3-ene-2-one
Type of composition:
boundary composition of the substance
State / form:
liquid
Reference substance:
Composition 1
Reference substance:
Composition 1
PBT status:
the substance is not PBT / vPvB
Justification:

Classification of Reaction mass of 4-(2,6,6-trimethylcyclohex-1-ene-1-yl)-but-3-ene-2-one and 4-(2,6,6-trimethylcyclohex-2-ene-1-yl)-but-3-ene-2-onefor effects in the environment:

 

The chemical Reaction mass of 4-(2,6,6-trimethylcyclohex-1-ene-1-yl)-but-3-ene-2-one and 4-(2,6,6-trimethylcyclohex-2-ene-1-yl)-but-3-ene-2-one (CAS no. 907-706-6) is used as a flavouring and fragrance agent.The aim was to assess whether the PBT criterion within Annex XIII was fulfilled forReaction mass of 4-(2,6,6-trimethylcyclohex-1-ene-1-yl)-but-3-ene-2-one and 4-(2,6,6-trimethylcyclohex-2-ene-1-yl)-but-3-ene-2-one.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

The Ready Biodegradability of test chemical was determined by the Manometric Respirometry Test according to the OECD Guidelines for Testing of Chemicals, Method No. 301 F. The test chemical undergoes 71% biodegradation after 28 days in the test conditions. The 10 -day window criterion is also fulfilled (16% biodegradation on day 4 and 65% on day 14). The curves obtained with the reference substance alone and with test chemical + reference substance show no toxic effect to the micro-organisms at the test concentration (100 mg/l). Thus, the test chemical should be regarded as readily biodegradable according to this test.

 

Another Manometric Respirometry Test was conducted of test chemical to assess its percent degradation as per the OECD Guidelines for Testing of Chemicals, Method No. 301 F. The Test chemical undergoes 60% biodegradation after 28 days (65% after 36 days) in the test conditions. Biodegradation exceeds 10% on day 8 and reaches only 52% at the end of the 10-day window (days 8 to 18).The curves obtained with the reference substance alone and with Test chemical + reference substance show no toxic effect of Test chemical to the micro-organisms at the test concentration (100 mg/I).Thus, Test chemical should be regarded as readily biodegradable according to this test.

 

Experimental results from the read across substance also indicate that they are readily biodegradable.

 

Thus, based on the available information, it indicates that chemical Reaction mass of 4-(2,6,6-trimethylcyclohex-1-ene-1-yl)-but-3-ene-2-one and 4-(2,6,6-trimethylcyclohex-2-ene-1-yl)-but-3-ene-2-one can be considered to be readily biodegradable in water and thus likely to be not persistent (not P) 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 BCF value from authoritative databases was determined to be158.7 L/kg and the octanol water partition coefficient of the test chemical was determined to be 4.1, 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

All of the available short-term eco-toxicity data for fish and algae for the substance Reaction mass of 4-(2,6,6-trimethylcyclohex-1-ene-1-yl)-but-3-ene-2-one and 4-(2,6,6-trimethylcyclohex-2-ene-1-yl)-but-3-ene-2-one indicates the LC50/EC50 value to be in the range > 7.5 to 50.26 mg/L, respectively and on the basis ofthe various experimental studies of shortterm eco-toxicity data for aq. Invertebratesof the structurally and functionally similar read across chemical (including the biodegradability of read across chemical) and applying the weight of evidence approach, the EC50 value was determined to be ranges from 2.65 to 5.7 mg/l, respectively. These value suggest that the substance is likely to be hazardous to aquatic organisms at environmentally relevant concentrations. Since the test chemical is readily biodegradable in nature, chemical can be considered as non-toxic to aq. organisms and thus can be considered to be ‘not classified’ as per the CLP regulation.

 

On the basis ofthe various experimental studies oflong term eco-toxicity data for fish and aq. Invertebratesof the structurally similar test chemical (including the biodegradability of read across chemical) and applying the weight of evidence approach, the NOEC value was determined to be ranges from 0.134 to 0.173 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 3’ as per the CLP regulation.

 

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.