Disodium succinate

PBT assessment

PBT assessment: overall result

Reference

Name:

disodium succinate

Type of composition:

boundary composition of the substance

State / form:

solid: bulk

Reference substance:

disodium succinate

PBT status:

the substance is not PBT / vPvB

Justification:

Classification of Disodium succinate for effects in the environment:

 

The chemical Disodium succinate (CAS no. 150-90-3) is used as an acidulant and flavouring agent for foods & as a protective coating for fruits and vegetables. It is also used as a chemical intermediate.The aim was to assess whether the PBT criterion within Annex XIII was fulfilled for Disodium succinate. 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 fulfils the P criterion within Annex XIII based on the assessment that here follows:

 

Biotic degradation

Various experimental key and supporting studies of the test chemical were reviewed for the biodegradation end point which are summarized as below:

 

In an experimental key study from study report (2018), 28-days Closed Bottle test following the OECD guideline 301 D to determine the ready biodegradability of the test chemical. 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 76.5%. Degradation of Sodium Benzoate exceeds 45.18% on 7 days & 70.48% 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 0.67 mgO2/mg. ThOD was calculated as 0.69 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 97.1%. Based on the results, the test item, under the test conditions, was considered to be readily biodegradable in nature.

 

For the test chemical, the Biodegradation experiment was carried out for determining biodegradability of test chemical following the OECD Guideline 301 C "Ready Biodegradability: Modified MITI Test (I)" under aerobic conditions (from authoritative database, handbook and secondary source, 2018). In this experiment, non-adapted activated sludge was used as test inoculum for the study at 30 mg/L concentration. Aniline was used as a reference substance for the study. The initial concentration of test chemical was 100 mg/L. Biodegradation was analyzed by using three parameters namely O2 consumption (BOD), TOC removal and test material analysis by HPLC. After 14 days of incubation, percent biodegradation of test chemical was determined to be 72 % by O2 consumption (BOD) parameter 100 % by TOC removal and test material analysis by GC parameter, respectively. Therefore, it is concluded that test chemical is considered to be readily biodegradable in water.

 

On the basis of above results for test chemical Disodium succinate, it can be concluded that the test chemical can be considered to be readily biodegradable in natureand 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 70.7%). In soil,Disodium succinatewas expected to have rapid mobility based upon a Log KOC value of 1.078, respectively. The half-life in soil (17.33 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, 29.3% and 0.0587% of the chemical will partition into water & sediment according to the Mackay fugacity model level III in EPI suite version 4.1 (2017). However, the half-life (8.66 days in water and 77.916 days in sediment estimated by EPI suite) indicates that the chemical is not persistent in water & sediment and the exposure risk to aquatic & sediment dwelling animals is moderate to low.

 

Hence it has been concluded that Disodium succinate 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:

 

The estimated BCF value from authoritative databases was determined to beranges from 3.162 to 3.89, respectively and the octanol water partition coefficient of the test chemical was determined to -0.56 to -0.59, 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 data for fish, invertebrates and algae for the substanceDisodium succinateindicates the LC50/EC50 value to be in the range 100.99 to > 1000 mg/L, respectively and on the basis ofthe available data oflong term eco-toxicity data for aq. Invertebrates, both the NOEC and EC50 value was determined to be ranges from > 100 mg/l, respectively. These value suggest that the substance is likely to be not hazardous to aquatic organisms at environmentally relevant concentrations and can be considered to be ‘not classified’ as per the CLP regulation.

 

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.