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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

Key value determined using EU Method C3, OECD guideline 201 and STN EN ISO 8692.

Key value for chemical safety assessment

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

Additional information

As stated, all conditions of the test were met during the growth inhibition tests conducted on freshwater algaeSelenastrum capricornutum. In the tests conducted on all controls(both the controls and ‘control A’s), the algal cell density (number of cells per ml) increased at least 103 x and the growth rate reached µ > 1.54 d-1; at the same time, pH changes did not exceed 1.38 units. Equally, the 72 h EbC(IbC)50 and 72 h ErC(IrC)50 values established for the reference substance - potassium dichromate (K2Cr2O7) comply with the required values, therefore, the results of the growth inhibition tests in freshwater algaeSelenastrum capricornutum can be considered valid.

Given the fact that at test concentrations ≥ 25 mg/l , the test substance gradually separated from the solution during the tests despite the application of an auxiliary substance(acetone p.a.), it can be assumed that the values for the growth inhibition of algae Selenastrum capricornutum for the individual concentrations do not correspond with the actual concentration of the test substance DUSANTOX® 86 in the solution, therefore, the 72 h EbC(IbC)50 and 72 h ErC(IrC)50 values may be inaccurate; in any case, the 72 h EbC(IbC)50 and 72 h ErC(IrC)50 values for the test substance DUSANTOX® 86 (for all five samples) are > 10 mg/l.

 

In accordance with ECHA Guidance document, Chapter R.7b – Endpoint Specific Guidance, “Figure R. 7.8-5: Considerations for difficult substances” the limit value of 100 mg/l is taken as the definitive value for hazard classification purposes. The substance is not considered to be harmful to algae at the limit of concentration in water. No classification is applicable.