Disodium [3-[(4,5-dihydro-3-methyl-5-oxo-1-phenyl-1H-pyrazol-4-yl)azo]-4-hydroxy-5-nitrobenzenesulphonato(3-)][2-[(2-hydroxybenzylidene)amino]-4-nitrophenolato(2-)-N2,O1,O2]chromate(2-)

Toxicity to aquatic plants other than algae

Description of key information

The 7d-ErC10 (dry weight) was determined at 0.837 mg/L (measured), the ErC50 at 12.3 mg/L for the structural analogue substance Acid Red 315.

Key value for chemical safety assessment

EC50 for freshwater plants:

12.3 mg/L

EC10 or NOEC for freshwater plants:

0.837 mg/L

Additional information

Significant inhibitory effects were determined for all parameters at 1.95, 6.25 and 20.0 mg/L (nominal) and 1.64, 5.25 and 18.4 mg/L (actual). The actual EC10-value for yield of frond numbers was determined to be 0.297 mg/L, the actual EC10-value for growth rate of frond numbers was determined to be 0.837 mg/L. The actual EC10-value for yield of dry weight was determined to be 0.591 mg/L, the actual EC10-value for growth rate of dry weight was determined to be 1.10 mg/L.

The actual EC50-value for yield of frond numbers was determined to be 2.54 mg/L, the actual EC50-value for growth rate of frond numbers was determined to be 12.3 mg/L. The actual EC50-value for yield of dry weight was determined to be 3.48 mg/L, the actual EC50-value for growth rate of dry weight was determined to be 10.1 mg/L.

The test is valid as the doubling time of control frond numbers was calculated to be 37.9 h, corresponding to 1.581 days at day 7. This is less than the maximum allowable doubling time set in OECD guideline 221 (60 h, 2.5 days).