Hydrogen [4-[4-(dimethylamino)-α-(2-hydroxy-3,6-disulphonato-1-naphthyl)benzylidene]cyclohexa-2,5-dien-1-ylidene]dimethylammonium, monosodium salt

PBT assessment

PBT assessment: overall result

PBT status:

the substance is not PBT / vPvB

Justification:

Classification of Hydrogen [4-[4-(dimethylamino)-alpha-(2-hydroxy-3,6-disulphonato-1-naphthyl)benzylidene]cyclohexa-2,5-dien-1-ylidene]dimethylammonium, monosodium salt for effects in the environment:

 

The chemical Hydrogen [4-[4-(dimethylamino)-alpha-(2-hydroxy-3,6-disulphonato-1-naphthyl)benzylidene]cyclohexa-2,5-dien-1-ylidene]dimethylammonium, monosodium salt (CAS no. 3087-16-9) is used for dyestuff application as well as a laboratory reagent. The aim was to assess whether the PBT criterion within Annex XIII was fulfilled for Hydrogen [4-[4-(dimethylamino)-alpha-(2-hydroxy-3,6-disulphonato-1-naphthyl)benzylidene]cyclohexa-2,5-dien-1-ylidene]dimethylammonium, monosodium salt. 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

 

Biodegradability of Hydrogen [4-[4-(dimethylamino)-α-(2 -hydroxy-3,6 -disulphonato-1 -naphthyl)benzylidene]cyclohexa-2,5 -dien-1 -ylidene]dimethylammonium, monosodium salt (CAS no. 3087 -16 -9) is predicted using QSAR toolbox version 3.3 with logKow as the primary descriptor (2017). Test substance undergoes 1.86% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical Hydrogen [4 -[4 -(dimethylamino)-α-(2 -hydroxy-3,6 -disulphonato-1 -naphthyl)benzylidene]cyclohexa-2,5 -dien-1 -ylidene]dimethylammonium, monosodium salt was estimated to be not readily biodegradable in water.

 

Further, various supporting studies for read across substances (CAS: 1694-09-3; 3520-42-1 and 55250-84-5), also indicate that the substances are not readily biodegradable in nature.

 

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 68.7 and 29.9%).In soil,Hydrogen [4-[4-(dimethylamino)-α-(2 -hydroxy-3,6 -disulphonato-1 -naphthyl)benzylidene]cyclohexa-2,5 -dien-1 -ylidene]dimethylammonium, monosodium saltwas expected to have rapid mobility based upon an experimental Log Koc 0.269. Thehalf-life in sediment and soil (541.66 days and 120 days estimated by EPI suite) indicates that the chemical is persistent in sediment and soil.

 

If released in to the environment, only 1.43 % 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 exposure risk to aquatic animals is moderate to high.

 

Although the half-life values suggest classification as very persistent (vP), the substance is classified only as persistent (P) since only estimated half-life values are available for the same Hence it has been concluded thatHydrogen [4-[4-(dimethylamino)-α-(2 -hydroxy-3,6 -disulphonato-1 -naphthyl)benzylidene]cyclohexa-2,5 -dien-1 -ylidene]dimethylammonium, monosodium saltis persistent 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 was determined to be 3.2 L/kg wet wt. and theexperimentaloctanol water partition coefficient of the test chemical is 0.595 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 estimation for fish, invertebrates and algae for the substance indicates the LC50/EC50 value to be >100 mg/L. These value suggest that the substance is likely to be non-hazardous to Aquatic organisms at environmentally relevant concentrations and has been considered as not classified as per the CLP regulation.

 

There are no available long-term toxicity evaluations forHydrogen [4-[4-(dimethylamino)-α-(2 -hydroxy-3,6 -disulphonato-1 -naphthyl)benzylidene]cyclohexa-2,5 -dien-1 -ylidene]dimethylammonium, monosodium salt. 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.