Cuprate(4-), [.mu.-[[3,3'-[(1-oxido-1,2-diazenediyl)bis[[2-(hydroxy-.kappa.O)-4,1-phenylene]-2,1-diazenediyl-.kappa.N1]]bis[4-(hydroxy-.kappa.O)-2,7-naphthalenedisulfonato]](8-)]]di-, ammonium sodium

Short-term toxicity to aquatic invertebrates

Description of key information

The following endpoint values were determined on the basis of the nominal test item concentrations after 48 h of exposure: 
EC50/48 h value is 2.52 mg/L (95% confidence interval 1.75 – 3.44).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

2.52 mg/L

Additional information

Key study

Immobilization of Daphnia magna exposed to the test item was investigated during a 48-hour static test. The test was performed in glass beakers of 150 mL capacity, containing 100 mL of each treatment per replicate. Eight test item concentrations: 0.8, 1.6, 3.2, 6.3, 12.5, 25, 50 and 100 mg/L plus the control were used. Daphnia magna was observed for immobilization after 24 and 48 h of exposure. The Daphnia magna was considered immobile if they showed no ability to swim within 15 seconds after agitation of the test vessel. At exposure termination in the test item concentrations of 0.8, 1.6, 3.2, 6.3, and 12.5 mg/L immobilization was 15, 45, 55, 65 and 95%, respectively. In the test item concentrations 25, 50 and 100 mg/L the immobilization was 100%. In the control the immobilization of Daphnia magna was 5%. The concentrations of the test item were determined with a validated spectrophotometric method. In the samples collected at exposure initiation the determined test item concentrations were in the range of 81.8 – 88.1% of nominal concentration. Therefore, the results confirm correct preparation of the test item concentrations. In the samples collected at exposure termination the determined test item concentrations were in the range of 80.8 – 86.2% of nominal concentration. Therefore, the test item concentrations were stable under test conditions. The following endpoint values were determined on the basis of the nominal test item concentrations after 48 h of exposure:

EC50/48 h value is 2.52 mg/L (95% confidence interval 1.75 – 3.44)

LOEC/48 h value 1.60 mg/L

NOEC/48 h value 0.80 mg/L.

Disregarded Study

The test substance was tested for its acute toxicity to Daphnia magna in a 48 hours static test (limit-test) according to OECD guideline 202 and EU method C.2. The daphnia were exposed to the test substance (12 mg/L) in 250 mL beakers containing 100 mL test medium with 10 animals per beaker. All tests are running in duplicate. Test evaluations were done by visual assessment of the mobility of the daphnia after 24 and 48 hours. Due to the low test substance concentration ( 12% act. ingr.) the study is considered to be disregarded and no EC50 value can be determined.