Sodium bis[2,4-dihydro-4-[[2-hydroxy-5-(methylsulphonyl)-4-nitrophenyl]azo]-5-methyl-2-phenyl-3H-pyrazol-3-onato(2-)]chromate(1-)

Short-term toxicity to aquatic invertebrates

Description of key information

A 48-h semi-static acute toxicity test (Institute of industrial organic chemistry, 2017) on neonates (< 24 h old) of Daphnia magna was performed under GLP conditions according to OECD 202 (2004). The EC50 value of the test item was determined to be higher than 6.16 mg/L after 48 hours.

Additional information

A 48-h semi-static acute toxicity test (Institute of industrial organic chemistry, 2017) on neonates (< 24 h old) of Daphnia magna was performed under GLP conditions according to OECD 202 (2004). The test was performed with the nominal concentrations: 140, 64, 29, 13, 6.0, 2.7 and 0 (control) mg/L. The highest test item concentration was prepared by mixing an appropriate amount of the test item with deionized water. The mixture and the control (deionized water) were mechanically shaken for 72 hours (30 ºC, 90 rpm, darkness). After shaking appropriate amounts of stock solutions for preparation of the ISO test water were added into the mixture and the control in order to obtain ISO test water. Lower test item concentrations were prepared by sequential dilutions with ISO test water. The test item concentrations and the control were left for settling phase (2h, no shaking, room temperature). The content of the main ingredient in the test item concentration was determined with a validated spectrophotometric method. Each sample in a volume of 10 mL (control sample, test sample and sample fortified with the standard) was chemically determined at exposure initiation (fresh) and at renewal (24h – old from separate replicates exposed under test conditions) were chemically determined. Moreover, samples of the highest and the lowest test item concentration and the control at renewal (fresh) and at exposure termination renewal (24h – old from separate replicates exposed under test conditions) were determined. Each sample of 10 mL volume ( i.e. control sample, test sample, sample fortified with standard) was directly analyzed without previous pretreatment. At exposure initiation of the test (fresh), the measured concentrations were determined to be 2.8, 5.7, 13.1, 27.8, 58.2 and 126.5 mg/L. After 24 hours (old), the measured concentrations were determined to be 91.7, 88.9, 97.3, 94.7, 90.6 and 91.1 mg/L. After 24 hours of the exposure (fresh), the measured concentrations were determined to be 2.4 and 123.3 mg/L. At the exposure termination (24 h-old) the measured concentrations were determined to be 2.2 and 123.1 mg/L. At exposure initiation and at renewal, in fresh test item concentrations, the determined test item concentrations were in the range of 88.1 – 104.9 % of nominal concentration. Therefore, the test item concentrations were prepared correctly. At exposure termination and at renewal, in 24h - old test item concentrations, the determined test item concentrations were in the range of 80.9 – 97.3 % of nominal concentration. Therefore, the test item concentrations were stable under the test conditions. Additionally the blank control was performed with ISO Test water (without the test substance) and the positive control was performed with potassium dichromate. The EC50 based on the nominal concentration of the reference material was determined to be 1.01 mg/L after 24 hours and 0.92 mg/L after 48 hours therefore the validity criteria were fulfilled. The EC50 value of the test item was determined to be higher than 6.16 mg/L after 48 hours.