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PBT assessment

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PBT assessment: overall result

Reference
Name:
4-(5,5,6-trimethylbicyclo[2.2.1]hept-2-yl)cyclohexan-1-ol
Type of composition:
boundary composition of the substance
State / form:
liquid
Reference substance:
4-(5,5,6-trimethylbicyclo[2.2.1]hept-2-yl)cyclohexan-1-ol
PBT status:
the substance is not PBT / vPvB
Justification:

Classification of 4-(5,5,6-trimethylbicyclo[2.2.1]hept-2-yl)cyclohexan-1-ol for effects in the environment:

 

The chemical 4 -(5,5,6 -trimethylbicyclo[2.2.1]hept-2 -yl)cyclohexan-1 -ol (CAS no. 66068-84-6) is used as a fragrance agent.The aim was to assess whether the PBT criterion within Annex XIII was fulfilled for 4 -(5,5,6 -trimethylbicyclo[2.2.1]hept-2 -yl)cyclohexan-1 -ol. 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

28-days Manometric respirometry test following the OECD guideline 301F to determine the ready biodegradability of the test chemical (Experimental study report, 2015). The study was performed at a temperature of 20± 1°C. Mixture of domestic waste water, surface soil and soil samples was used as a test inoculum for the study. This inoculum was collected and were mixed to get diluted suspension. The inoculum was kept aerobic until being used for experiment by supplying organic and inorganic sources required by micro flora to sustain at controlled laboratory conditions.  This gave the bacterial count as 107to 108 CFU/ml. At the regular interval microbial plating was also performed on agar to confirm the vitality and CFU count of microorganism. OECD mineral medium was used for the study. The test system included control, test item and reference item. The concentration of test and reference item ( Sodium Benzoate) chosen for both the study was 100 mg/L, while that of inoculum was 10 ml/l. 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 (Sodium Benzoate) was also calculated using BOD & ThOD and was determined to be 79.36%. The DO depletion(mg O2/l) in inoculum blank on 28th day was 24.2 mg O2/l which fulfilled the validity criteria (i.e., The DO depletion of the inoculums blank is normally 20-30 mg O2/l and should not be greater than 60 mg/l in 28 days) for inoculum blank (control). Degradation of Sodium acetate exceeds 64% after 4 days. Thus the activity of the inoculums is verified and the test is considered as valid.The BOD28 value of test chemical was observed to be 0.026 mgO2/mg. ThOD was calculated as 3.045 mgO2/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to manometric respirometry test was determined to be 0.85%.Based on the results, the test item, under the test conditions, was considered to be not biodegradable at 20 ± 1°C over a period of 28 days.

 

Thus, based on the available information, it indicates that chemical 4 -(5,5,6 -trimethylbicyclo[2.2.1]hept-2 -yl)cyclohexan-1 -ol can be considered to be not readily biodegradable in water and thus likely to be persistent (P) in nature.

 

Bioaccumulation assessment

The tested substance fulfils the B criterion within Annex XIII based on the assessment that here follows:

 

Theestimated BCF value from modelling databases was evaluated to be ranges from 5680 to 6420, respectively and theoctanol water partition coefficient of the test chemical ranges was estimated to be 5.27 to 5.5, which is greater than the threshold of 4.5. If this chemical is released into the aquatic environment, there should be a high risk for the chemical to bioaccumulate in fish and food chains.

 

Although BCF and partition coefficient value indicates that the chemical to be very bioaccumulative (vB), since only predicted data is available for the substance 4-(5,5,6 -trimethylbicyclo[2.2.1]hept-2 -yl)cyclohexan-1 -ol, chemical can be expected to be bioaccumulative (B) in the 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 4 -(5,5,6 -trimethylbicyclo[2.2.1]hept-2 -yl)cyclohexan-1 -ol is highly insoluble in water (solubility: less than 0.01 mg/L at 35° C). 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 fulfils the P and B criterion, but does not fulfil the T criterion and has therefore not been classified as a PBT compound within Annex XIII.

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