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Toxicity to aquatic algae and cyanobacteria

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Description of key information

The effect of test item 2-nitro-p-phenylenediamine, CAS No. 5307-14-2 was studied on the growth of fresh water green alga Chlorella vulgaris.The study was conducted following OECD guideline 201- Alga, growth inhibition test. The test concentration chosen for the study were 3.125mg/l , 6.25mg/l, 12.5mg/l, 25mg/l, 50mg/l, and 100mg/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 6.734mg/l. 

Key value for chemical safety assessment

EC50 for freshwater algae:
6.734 mg/L

Additional information

Various studies for the target chemical2-nitro-p-phenylenediamine and predicted data were reviewed to summarize the following information:

The effect of test item 2-nitro-p-phenylenediamine, CAS No. 5307-14-2 was studied [UERL Study Report, Sustainability Support Services (Europe) AB (Report no. 5307-14-2/01/2016/AT), 2016]on the growth of fresh water green algaChlorella vulgaris.The study was conducted following OECD guideline 201- Alga, growth inhibition test. The test concentration chosen for the study were 3.125mg/l, 6.25mg/l, 12.5mg/l, 25mg/l, 50mg/l, and 100mg/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 6.734mg/l.

Thus, based on the EC50 value, test substance can be classified as aquatic chronic category 2 as per the criteria of CLP regulation.Though the chemical2-nitro-p-phenylenediamineis not readily biodegradable but it has a BCF < 500 and hence the chemical is likely to be "not classified" for aquatic classification as per the CLP criteria.

72 hrs aquatic toxicity study (SSS QSAR prediction model, 2016) was conducted to assess toxic effects of the test compound 2-nitro-p-phenylenediamine(CAS no 5307-14-2) and the results were predicted. The study was based on the effects of the test compound on the Desmodesmus subspicatus in a static fresh water system. The predicted data suggests the effective concentration (EC50) for the test compound2-nitro-p-phenylenediaminewas estimated to be 221.109 mg/L on the basis of growth rate.

 

96 hrs aquatic toxicity study (EPI suite, 2016) was conducted to assess toxic effects of the test compound 2-nitro-p-phenylenediamine(CAS no 5307-14-2) and the results were predicted. The study was based on the effects of the test compound on green algae in a static fresh water system. The predicted data suggests the effective concentration (EC50) for the test compound 2-nitro-p-phenylenediamine(CAS no 5307-14-2) was estimated to be 535.358 mg/L on the basis of growth rate.

 

On the basis of the above resultsof various studies of toxicity to aquatic algae and cyanobacteria for target and its predicted data, it can be concluded thatthe substance can be classified as non- hazardous as per the criteria of CLP regulation.