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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

The EC50 for growth rate reduction (ERC50:0-72h) was beyond the range tested, i. e. exceeded a TWA concentration of 69 mg/l. The extrapolation result is around 30 g/l. Therefore, EC50 is > 100 mg/l.

Key value for chemical safety assessment

EC50 for freshwater algae:
100 mg/L
EC10 or NOEC for freshwater algae:
2.2 mg/L

Additional information

Pseudokirchneriella subcpitata is tested with Everzol Orange ED-G Crude. Test concentrations ranged at 0, 4.6, 10, 22, 46 and 100 mg/l. The initial cell density was 10000 cells/ml and the total test period was 72 hours. Samples for possible analysis were taken at the start, after 24 hours of exposure and at the end of the test.

At the start of the test, the actual test concentrations were in agreement with nominal. At the end of the 72-hour period the measured concentration had decreased to 31-50 % of initial values. Based on these results, the calculated Time Weight Average (TWA) concentrations were: 2.2, 5.3, 12, 27 and 69 mg/l.

The study met the acceptability criteria prescribed by the protocol and was considered valid.

The EC50 for yield inhibition (EyC50: 0 -72h), based on TWA concentrations, was 19 mg/l with a 95 % confidence interval.

The NOEC for growth rate reduction equaled a TWA concentration of 2.2 mg/l and the NOEC for yield inhibition was lower than 2.2 mg/l.

The EC50 for growth rate reduction (ErC50:0-72h) was beyond the range tested, i.e. exceeded a TWA concentration of 69 mg/l. Based on the linearity of the dose response, the data can be extrapolated. Based on extrapolation of the current data set, the calculated ErC50: 0 -72h is around 30000 mg/l. Therefore it is scientifically justified to state that the EC50 for growth rate reduction (ErC50: 0 -72h) > 100mg/l.