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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

The effect of 2 -sec butyl-4,6 dinitrophenol, batch provided by Crompton Manufacturing and supplied by Chemtura Corporation was tested on the single cell green alga Scenedesmus subspicatus as per the OECD Guideline No. 201.
The test item was tested at the concentrations of 0.030, 0.081, 0.219, 0.590, and 1.594 mg/L (the serial dilution factor was 2.7) along with a negative control and a positive control. The cell growth was measured at 24, 48, and 72 hours after initiation of the test.
The inhibition of growth was determined by calculating the EbC50 and ErC50 (the index "b" refers to "biomass" and the index "r" refers to "growth rate").
The test conditions fulfilled all the validity criteria of the guideline. Hence, the results of the test were considered valid.
The calculated EbC50 value over a period of 72 hours was 0.21 mg/L.
The calculated ErC50 value over a period of 72 hours was 0.74 mg/L.
The observed NOEC value based on 72 hours cell counts was 0.030 mg/L.
The observed LOEC value based on 72 hours cell count was 0.081 mg/L

Key value for chemical safety assessment

EC50 for freshwater algae:
0.74 mg/L
EC10 or NOEC for freshwater algae:
0.03 mg/L

Additional information

A reliability rating of 1 was assigned to the key study, according to the criteria of Klimisch, 1997 as the study was conducted in accordance with recognised guidelines and GLP.