A mixture of isomers of: 1,1'-[(3,5(or 2,4 or 4,6 or 2,6)-dihydroxy-o(or m or p)-phenylene)bis(azo-meta-phenyleneazo{1-[3-(dimethylamino)propyl]-1,2-dihydro-6-hydroxy-4-methyl-2-oxopyridine-5,3-diyl})]dipyridinium-dichloride-dihydrochloride; 1-(1-[3-(dimethylamino)propyl]-5-{3-[x-(4-{1-[3-(dimethylamino)propyl]-1,6-dihydro-2-hydroxy-4-methyl-6-oxo-5-pyridinio-3-pyridylazo}phenylazo)-2,4(or 2,6 or 3,5 or 4,6)-dihydroxyphenylazo]phenylazo}-1,2-dihydro-6-hydroxy-4-methyl-2-oxo-3-pyridyl)pyridinium-dichloride-dihydrochloride (where x is variable)

Short-term toxicity to aquatic invertebrates

Description of key information

EC50 (48 h) was 156.8 mg/l; NOEC with respect to mobility was 32 mg/l.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

156.8 mg/L

Additional information

OECD guideline 202. Daphnia were exposed for 48 hours to a concentration range of 32 to 1000 mg/l forming a geometric progression with a factor of 1.8. After 48 hours of exposure 100 % immobilisation was seen at concentrations of 320 mg/l and higher. At 180 mg/l the total incidence of immobility was 50 % and at 100 mg/l 20 %. No increase in immobility was observed at concentrations of 56 mg/l and lower. The 48h-EC50 was 156.8 mg/l with 95 % confidence interval ranging from 113.1 to 207.0 mg/l (slope = 5.4). Finally, the No Observed Effect Concentration with respect to mobility was found to be 32 mg/l after 48 hours of exposure.