6-aminonaphthalene-2-sulphonic acid

PBT assessment

PBT assessment: overall result

Reference

Name:

6-aminonaphthalene-2-sulphonic acid

Type of composition:

boundary composition of the substance

Reference substance:

6-aminonaphthalene-2-sulphonic acid

PBT status:

the substance is not PBT / vPvB

Justification:

Classification of 6-aminonaphthalene-2-sulphonic acid for effects in the environment:

 

The chemical 6-aminonaphthalene-2-sulphonic acid (CAS no. 93-00-5) is used as an intermediate for chemical synthesis & dyestuff applications and also used as a laboratory agent. The aim was to assess whether the PBT criterion within Annex XIII was fulfilled for 6-aminonaphthalene-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 does not fulfil the P criterion within Annex XIII based on the assessment that here follows:

 

Biotic degradation

In an experimental key study report, 28-days Closed Bottle test following the OECD guideline 301 D to determine the ready biodegradability of the test item. The study was performed at a temperature of 20°C. The test system included control, test item and reference item. Polyseed were used for this study. The concentration of test and reference item (Sodium Benzoate) chosen for both the study was 4 mg/L, while that of inoculum was 32 ml/l. OECD mineral medium was used for the study. 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 (reference item) was also calculated using BOD & ThOD and was determined to be 78.31%. Degradation of Sodium Benzoate exceeds 45.18% on 7 days & 59.03% on 14th day. The activity of the inoculum was thus verified and the test can be considered as valid. The BOD28 value of test chemical was observed to be 1.07 mgO2/mg. ThOD was calculated as 1.64 mgO2/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 65.24%. Based on the results, the test item, under the test conditions, was considered to be readily biodegradable in nature.

 

For the test chemical from peer reviewed journal (Bernd Nortemann et. al, 1986), biodegradation experiment was conducted for 6 days at 30°C for evaluating the percentage biodegradability of test substance 6-aminonaphthalene- 2-sulphonic acid (CAS no. 93-00-5). Initial test substance conc. used in the study was 1786 mg/l. The percentage degradation of test substance 6-aminonaphthalene- 2-sulphonic acid was determined to be >90% by HPLC in 6 days.

 

Thus, based on the available information, it indicates that chemical 6-aminonaphthalene-2-sulphonic acid can be considered to be readily 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 84.8%). In soil, 6-aminonaphthalene-2-sulphonic acid was expected to have moderate mobility based upon a Log KOC value 2.06, respectively. The half-life in soil (75 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, 15% 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 (37.5 days estimated by EPI suite) 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 0.153% when estimated by EPI Suite version 4.1).

 

Hence it has been concluded that 6-aminonaphthalene-2-sulphonic acid is 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:

 

Theoctanol water partition coefficient of the test chemical ranges from was determined to be ranges from -0.91 to 0.6, 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 estimations for fish, invertebrates and algae for the substance indicates the LC50/EC50 value to be in the range 100 to > 200 mg/L, respectively. 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 for 6-aminonaphthalene-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 does not fulfil the P, B and T criterion and has therefore not been classified as a PBT compound within Annex XIII.