2-[4-[[2-(cyanoimino)hexahydro-4,6-dioxo-5-pyrimidyl]azo]phenyl]-6-methylbenzothiazole-7-sulphonic acid, compound with 2,2',2''-nitrilotris[ethanol] (1:1)

Short-term toxicity to aquatic invertebrates

Description of key information

In a GLP static immobilization test (Institute of Industrial Organic Chemistry, 2017), Daphnia magna (< 24 h old) were exposed to the test item for 48 hours according to the OECD 202 (1992). The 48h-EC50 was determined to be > 120 mg/L.

Additional information

In a GLP static immobilization test (Institute of Industrial Organic Chemistry, 2017), Daphnia magna (< 24 h old) were exposed to the test item for 48 hours according to the OECD 202 (1992). The test solutions used in the test were prepared by mechanical dispersion. The definitive test was performed with a single test item concentration of 120 mg/L as limit test. An appropriate amount of test item (120.1 mg) was weighed in a glass crystallizer and quantitatively transferred into flask by multiple washing with the Elendt M7 medium and filled up to 1000 mL. Eight replicates were used for the test item concentration and the control, each with five Daphnia magna. Daphnia magna were observed for immobilization after 24 and 48 hours of exposure. The content of the main ingredient in the test item concentration was determined with a validated spectrophotometric method. Samples of the test item concentration and the control at exposure initiation and at exposure termination were chemically analyzed. In the sample collected at exposure initiation, the determined content of the main ingredient in the test item concentration was 109.2 mg/L (91.0 % of nominal concentration). Therefore, the results confirm correct preparation of the test item concentration. In the sample collected at exposure termination, content of the main ingredient in the test item concentration was 103.8 mg/L (86.5 % of nominal concentration). Therefore, the test item concentration was stable under test conditions. During exposure, no immobilization of Daphnia magna was observed in the control. An untreated control (test medium without addition of the test item) and a toxic reference control with potassium dichromate were performed. The 24h-EC50 of potassium dichromate was determined to be 1.01 mg/L. The validity criteria were fulfilled. At exposure termination, in the test item concentration of 120 mg/L, the immobilization of Daphnia magna was 2.5 %. After 48 hours the EC50 was determined to be > 120 mg/L.

In addition, to assess the aquatic toxicity of the test substance, a 48 hours static supporting test (Ciba-Geigy, 1996) was conducted on daphnia magna. The substance was tested in one (limit) concentration of 100 mg/L (nominal). Potassium dichromate was used as positive control. Daphnia were observed after 24 hours and after 48 hours and immobilization was recorded. As a result, only one daphnid was found immobile after 48 hours and therefore the EC50 was determined to be greater than 100 mg/L. The study was regarded as supporting information.