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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

Cu(II)-IDHA_OECD201_Pseudokirchneriella subcapitata: ErC50 (72h) > 250 mg/L; NOEC (72h) = 1 mg/L

Key value for chemical safety assessment

EC50 for freshwater algae:
250 mg/L
EC10 or NOEC for freshwater algae:
1 mg/L

Additional information

The acute toxicity of Cu(II)IDHA towards the green algae Pseudokirchneriella subcapitata was investigated in a 72 hours static toxicity laboratory study according to OECD 201 and in compliance with GLP (Rzodeczko, 2011). The initial density of algae was 10 000 cells/mL. The following concentrations of the test item Cu(II) IDHA were applied: 1.0; 2.6; 6.4; 16; 40; 100 and 250 mg/L. The test item Cu(II) IDHA contains aspartic acid (N-1,2 dicarboxyethyl) complexed with copper. The effect of algal growth inhibition is related with test item and increases with test concentration. In highest test concentration 250 mg/L the observed inhibition of algal growth may be overlapped with indirect effect related to blue colour of the solution. In test concentrations 6.4; 16; 40 and 100 mg/L few algae cells of twice the size of algal cells in the control were observed with microscope. In the highest test concentration 250 mg/L different types of algae cells were observed, i.e. some rod-shaped cells, some S-shaped cells, few cells bigger of twice the size of normal cells, few cells without changes of normal size and shape. No differences in size or shape of algal cells in lowest test concentrations 1.0 and 2.6 mg/L were observed as compared to the algae cells in the control. The ECx values were determined based on nominal concentrations of Cu(II) IDHA.

The determined ErC50 (72h) is higher than 250 mg/L (the highest test concentration) whereas EyC50 (72h) amounts to 54.57 mg/L. The ErC10 (72h) value is 18.41 mg/L. The LOEC (Lowest Observed Effect Concentration) and NOEC (No Observed Effect Concentration) values are 2.6 mg/L and 1.0 mg/L, respectively.