4',5'-dibromo-3',6'-dihydroxyspiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one

PBT assessment

PBT assessment: overall result

PBT status:

the substance is not PBT / vPvB

Justification:

Classification of 4',5'-dibromo-3',6'-dihydroxyspiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one for effects in the environment:

 

The chemical 4',5'-dibromo-3',6'-dihydroxyspiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one (CAS no. 596-03-2) is used for dyestuff application. The aim was to assess whether the PBT criterion within Annex XIII was fulfilled for 4',5'-dibromo-3',6'-dihydroxyspiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-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 fulfils the P criterion within Annex XIII based on the assessment that here follows:

 

Biotic degradation

Biodegradation in water ability was predicted for the test substance D & C Orange No. 5 (CAS no. 596 -03 -2) using the SSS QSAR prediction model (SSS QSAR Prediction Model, 2016).The ready biodegradability of the test substance D & C Orange No.5 was estimated as 9.8% in 28 days by using BOD parameter. This result indicates that D & C Orange no. 5 was estimated to be not readily biodegradable in water.

 

Estimation Programs Interface Suite (EPI suite, 2016) was run to predict the biodegradation potential of the test compound D & C Orange No. 5 (CAS no. 596 -03 -2). The screening tests ready biodegradability of the test substance was calculated using the software BIOWIN v4.10. The results indicate that D & C Orange No. 5 is not expected to be readily biodegradable in nature.

 

Various studies on read across substances (CAS: 518-47-8 and 16423-68-0) also indicate the substances to be not readily biodegradable.

 

Environmental fate

According to the fugacity model levels III, the most likely environmental fate for this test chemical is sediment and soil (i.e.estimated to 51.4% and 46.7% respetively). In sediment and soil, the substance was expected to have low mobility based upon a Log KOC of 5.13. The half-life in sediment and soil (541.6 days and 120 days, respectively estimated by EPI suite) indicates that the chemical is persistent the exposure risk to sediment and soil dwelling animals is moderate high.

 

If released in to the environment, 1.85 % of the chemical will partition into water according to the Mackay fugacity model level III in EPI suite version 4.1 (2016). However, the half-life (60 days estimated by EPI suite) indicates that the exposure risk to aquatic animals is moderate.

Hence it has been concluded that 4',5'-dibromo-3',6'-dihydroxyspiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one is persistent in nature.  

 

 

Bioaccumulation assessment

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

 

The estimated log octanol-water partition coefficient (log Kow) was determined to 5.13. If this chemical is released into the aquatic environment, there should be a moderate 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

The QSAR predictions for EC50/LC50 values were in the range of 8.47 to 16.96 mg/L. Based on the lowest available EC50/LC50, 4',5'-dibromo-3',6'-dihydroxyspiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one was suggested to be classified as ‘Aquatic chronic Category 2’.

 

There are no available long-term toxicity evaluations for 4',5'-dibromo-3',6'-dihydroxyspiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one. By speculation, although the substance is classified as per the CLP criterion, since the EC50/LC50 values are above 5 mg/L, we can consider that the classification for aquatic toxicity will not be applicable as per Annex XIII criteria for all of the tropic levels and the same is based on the above mentioned studies.

 

 

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.