7-acetamido-4-hydroxy-3-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]naphthalene-2-sulphonic acid

PBT assessment

PBT assessment: overall result

PBT status:

the substance is not PBT / vPvB

Justification:

Classification of 7 -acetamido-4 -hydroxy-3 -[[4 -[[2 -(sulphooxy)ethyl]sulphonyl]phenyl]azo]naphthalene-2 -sulphonic acid for effects in the environment:

 

The chemical7-acetamido-4-hydroxy-3-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]naphthalene-2-sulphonic acid (CAS no. 68189-39-9) is used as a color additive in foods.The aim was to assess whether the PBT criterion within Annex XIII was fulfilled for7-acetamido-4-hydroxy-3-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]naphthalene-2-sulphonic acid. 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

Biodegradbility of test chemical 7-acetamido-4-hydroxy-3-[(E)-2-{4-[2-(sulfooxy)ethanesulfonyl]phenyl}diazen-1-yl]naphthalene-2-sulfonic acid was predicted by using OECD QSAR tool box v3.3 using log Kow as primary descriptor. The test chemical 7-acetamido-4-hydroxy-3-[(E)-2-{4-[2-(sulfooxy)ethanesulfonyl]phenyl}diazen-1-yl]naphthalene-2-sulfonic acid showed 1.7 % degradation by considering BOD as parameter and microrganisms as inoculum  in 28 days. Based on Percent biodegradability it is concluded that this test chemical is not readily biodegradable.

 

Another prediction done by using the Estimation Programs Interface Suite (EPI suite, 2017), the biodegradation potential of the test compound7-acetamido-4-hydroxy-3-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]naphthalene-2-sulphonic acid(CAS no. 68189-39-9)in the presence of mixed populations of environmental microorganisms was estimated. The biodegradability of the substance was calculated using seven different models such as Linear Model, Non-Linear Model, Ultimate Biodegradation Timeframe, Primary Biodegradation Timeframe, MITI Linear Model, MITI Non-Linear Model and Anaerobic Model (called as Biowin 1-7, respectively) of the BIOWIN v4.10 software. The results indicate that chemical 7-acetamido-4-hydroxy-3-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]naphthalene-2-sulphonic acidis expected to be not readily biodegradable.

 

Experimental results from the similar substances (CAS: 17095-24-8 and 12225-88-6) also indicate that they are not readily biodegradable.

 

Environmental fate

According to the fugacity model levels III, the most likely environmental fate for this test chemical is soil (i.e. estimated to 90%). In soil,7-acetamido-4-hydroxy-3-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]naphthalene-2-sulphonic acidwas expected to have negligible to slow mobility based upon a Log Koc value ranging from 3.1124 to 3.8668, respectively. The half-life in soil (120 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, 9.2% 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 (60 days estimated by EPI suite) indicates that the chemical is persistent in water and the exposure risk to aquatic animals is moderate to high. 

 

Moreover, its persistent characteristic is also observed in the sediment compartment but Fugacity modelling shows that sediment is not an important environmental fate (less than 1% when estimated by EPI Suite version 4.1).

 

Hence it has been concluded that7-acetamido-4-hydroxy-3-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]naphthalene-2-sulphonic acidis 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 1 to 3.162, respectively and theoctanol water partition coefficient of the test chemical is -3.2963 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 estimations for invertebrates and algae for the substance indicates the LC50/EC50 value to be in the range 300.026 to 631.974 mg/L. These value suggest that the substance is not likely to be hazardous to Aquatic organisms at environmentally relevant concentrations and can be considered to be ‘not classified’ as per the CLP regulation.

 

There are no available long-term toxicity evaluations for7-acetamido-4-hydroxy-3-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]naphthalene-2-sulphonic acid. 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 fulfils the P criterion but does not fulfil the B and T criterion and has therefore not been classified as a PBT compound within Annex XIII.