Reaction mass of 2-[4-[(Hexahydro-2,4,6-trioxo-5-pyrimidyl) azo]phenyl]-6-methylbenzothiazole-7-sulphonic acid, compound with 2,2',2''-nitrilotris[ethanol] (1:1) and Lithium 2-[4-[(hexahydro-2,4,6-trioxopyrimidin-5-yl)azo]phenyl]-6-methylbenzothiazole-7-sulphonate

Short-term toxicity to fish

Description of key information

The 96 hour LC50 of the test substance was was determined to be >250 mg/L in nominal and >111.2 mg/L based on the mean measured concentrations.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

111.2 mg/L

Additional information

Key study

In a 96 hour acute toxicity study, zebrafish (Danio rerio) were exposed to the test item at nominal concentrations of 0 (control), 250 mg/L under static conditions in accordance with the OECD 203 test guideline and in compliance with GLP principles (BASF SE, 2018). The water pH, temperature and dissolved oxygen were within acceptable guideline specifications. The initial measured concentration of the test substance was 44% of the expected nominal concentration at the start of exposure and 45% of the expected nominal concentration at the end of the exposure. This deviation from the nominal value is likely due to the poor solubility of the test chemical in test medium. Undissolved test substance was removed by a centrifugation step prior to analysis. After 96-hours of exposure, the measured concentration was 100% of the initial measured value. Thus, the test substance was stable in solution under test conditions and mean measured concentrations are an accurate representation of exposure levels maintained throughout the test period. The results in this study are consistent with all validity criteria and the test is valid according to the guidelines of this study. No deviations from test guidelines or other incidents occurred during the course of the reported test which may have influenced the results. The 96 hour LC50 was >250 mg/L based on the nominal concentration of the test substance and 111.2 mg/L based on the mean measured concentrations. The test substance had no observable acute effect on fish up to 111.2 mg/L in test media and under test conditions.

Supporting study

A supporting study (Union Carbide Corporation Environmental Services, 1979a) was conducted on bluegill sunfish (Lepomis macrochirus Refinesque). Groups of ten fish were exposed to nominal concentrations of 180, 320, 560, 1000 and 1800 mg/L of the test substance (concentrate). At the beginning of the test and every 24 hours thereafter dissolved oxygen and pH of the control and each test concentration, and temperature of the water bath, were determined. Mortalities and abnormal behavioral responses were recorded every 24 hours. As a result, no mortalities occurred, therefore the LC50 was determined to be greater than 1800 mg/L. As fish of all test groups exhibited behavioral abnormalities (swimming near the surface), the NOEC was found to be < 180 mg/L.

Studies disregarded due to major methodological deficiencies

Another study (BASF AG, 1984) was conducted to determine the acute toxicity of the test substance on the Zebra fish (Brachydanio rerio HAM. and BUCH.) The study was performed using a static procedure. Zebra fish were exposed over a 96-hour period at a range of 4 concentrations: 50, 100, 5000 and 10000 mg/L and an untreated control. The study procedure was based on the OECD guideline 203. No effects were observed at concentrations up to 5000 mg/L. At the highest concentrations, all fish died. Therefore, the NOEC was determined to be 5000 mg/L and the LC50 was found to be > 5000 and <10000 mg/L. As the test substance was administered as a preparation containing less than 20 % of the test substance the study was disregarded due to major methodological deficiencies.

An acute toxicity test with fish (BASF Corporation, 1979b) is available in which a preparation of the substance (containing less than 20 % of the dye stuff) was tested. Bluegill sunfish (Lepomis macrochirus Refinesque) were used as test animals and exposed in groups of ten fish to nominal concentrations of 320, 560, 1000, 1800 and 3200 mg/L. At the beginning of the test and every 24 hours thereafter dissolved oxygen and pH of the control and each test concentration, and temperature of the water bath, were determined. Mortalities among the test fish, and any observable abnormal behavioral responses, were noted and recorded every 24 hours. The no effect concentration was determined, by observation, at 96 hours. As a result, the NOEC was found to be 320 mg/L and the L50 (96 h) was determined to be 1074.1 mg/L. As the test substance was administered as a preparation containing less than 20 % of the test substance the study was disregarded due to major methodological deficiencies.

Overall conclusion

Based on the most current and reliable study (BASF SE, 2018), the 96-h LC50 of the test item was determined to be 111.2 mg/L based on the mean measured concentrations and >250 mg/L in nominal. This result is supported by a an older and less reliable acute toxicity test with fish (BASF Corporation, 1979a). In this study the 96-h LC50 was determined to be greater than 1800 mg/L. As fish of all test groups exhibited behavioral abnormalities (swimming near the surface), the NOEC was found to be < 180 mg/L.