Disodium 2-(3-oxo-6-oxidoxanthen-9-yl)benzoate

Toxicity to aquatic algae and cyanobacteria

Description of key information

The effect of test item Disodium 2-(3-oxo-6-oxidoxanthen-9-yl) benzoate, CAS No. 518-47-8 was studied on the growth of fresh water green algaChlorella vulgaris[UERL Study Report, Sustainability Support Services (Europe) AB (Report no. 518-47-8/01/2016/AT), 2016].The study was conducted following OECD guideline 201- Alga, growth inhibition test. The test concentration chosen for the study were 6.25mg/l, 12.5mg/l, 25mg/l, 50mg/l, 100mg/l and 200mg/l. The test concentrations were prepared using stock solution of the test item using mineral media. The green alga was exposed to the test concentration for a period of 72 hours to observe average specific growth rate and % growth inhibition under the effect of the test item. EC50 calculated graphically through probit analysis was observed to be 209.24 mg/l. Thus, based on the EC50 value, test substance can be considered as non-toxic to aquatic organisms and thus cannot be classified as hazardous as per the CLP criteria.

Key value for chemical safety assessment

EC50 for freshwater algae:

209.24 mg/L

Additional information

Various study and predicted data for the target chemical Sodium fluorescein (CAS no 518-47-8) were reviewed to summarize the following information:

The effect of test item Disodium 2-(3-oxo-6-oxidoxanthen-9-yl) benzoate, CAS No. 518-47-8 was studied on the growth of fresh water green algaChlorella vulgaris[UERL Study Report, Sustainability Support Services (Europe) AB (Report no. 518-47-8/01/2016/AT), 2016].The study was conducted following OECD guideline 201- Alga, growth inhibition test. The test concentration chosen for the study were 6.25mg/l, 12.5mg/l, 25mg/l, 50mg/l, 100mg/l and 200mg/l. The test concentrations were prepared using stock solution of the test item using mineral media. The green alga was exposed to the test concentration for a period of 72 hours to observe average specific growth rate and % growth inhibition under the effect of the test item. EC50 calculated graphically through probit analysis was observed to be 209.24 mg/l. Thus, based on the EC50 value, test substance can be considered as non-toxic to aquatic organisms and thus cannot be classified as hazardous as per the CLP criteria.

 

72 hrs aquatic toxicity study was predicted(SSS QSAR Prediction model, 2016),to assess toxic effects of the test compound Sodium fluorescein (CAS No. 518 -47 -8) and the results were predicted. The study was based on the effects of the test compound on Pseudokirchneriella subcapitata in a static fresh water system. The predicted data suggests theeffective concentration (EC50) for the test compound Sodium fluorescein (CAS No. 518 -47 -8) was estimated to be 107.5449 mg/l on the basis of population.Thus, based on this value. it can be concluded that the substance can be considered as non-toxic to aquatic organisms and thus cannot be classified as hazardous as per the CLP criteria.

 

 

Ecotoxicological assessment of chemical Fluorescein was estimated (Malcolm S. Field et. al; 1995) to evaluate the toxicity of chemical to green algae. The concern levels identified by use of the SAR technique are expressed ad HIGH, MODERATE, LOW. These values are toxicity values, not exposure values. SAR results are generally regarded by EPA as being reliable. Dyes with aquatic toxicity values below 1mg/l received a HIGH concern rating; those with toxicity values ranging from 1-100mg/l received a MODERATE concern rating and those with toxicity values greater than 100mg/l received a LOW concern rating. The Median Effective Concentration which is estimated to be sublethal to 50% of Green Algae in 96 hours exposure to the test chemical (EC50) was determined to be <10 mg/l. As the EC50 for the test chemical lies between 1 – 100mg/l, it falls in moderate category in the aquatic toxicity ratings. Based on the EC50 value, it can be concluded that the substance can be classified as aquatic chronic category 2. Since the partition coefficient of the test chemical is 0.34, Fluorescein can be considered as non-toxic to aquatic organisms and thus cannot be classified as hazardous as per the CLP criteria.

 

Based on the overall reported results of study and predicted data for target substance, it can be concluded that the substance can be considered as non-toxic to aquatic organisms and thus can be classified as not hazardous as per the CLP criteria.