Disodium 4,4'-bis[(4-anilino-6-morpholino-1,3,5-triazin-2-yl)amino]stilbene-2,2'-disulphonate

Long-term toxicity to fish

Description of key information

NOEC (fry length) < 0.625 mg/l (nominal)

EC10 (fry weight) < 0.625 mg/l (nominal)

 

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

NOEC

Effect concentration:

0.625 mg/L

Additional information

The effects of the test item on the early-life stage of fish (Danio rerio / Zebrafish) were determined according to OECD Guideline 210. DMSO was used as solvent with a concentration of 0.10 ml/l dilution water. Stock solutions in DMSO with nominal concentrations of 100, 50.0, 25.0, 12.5 and 6.25 g/l were prepared in appropriate intervals of 7 days and continuously dosed to the dilution water in a flow-through system. Based on the results of a range finding test the test was conducted as a dose-response test with the nominal test item concentrations 0.625, 1.25, 2.50, 5.00 and 10.0 mg/l. The test was started by placing fertilized eggs into the test vessels and it lasted 35 days (30 days post-hatch). 80 eggs of Danio rerio / zebrafish were exposed to each test concentration, the solvent control and the control (4 replicates with 20 eggs each). The water quality parameters pH-value, oxygen concentration, temperature and total hardness were within the acceptable limits. On study day 5, 91% of the control and 90% the solvent control larvae had hatched. Therefore, study day 5 was defined as post hatch day 0 (= PHD 0). Different toxicological endpoints were determined: hatching success, fry growth (assessed via length and fresh weight measurements on PHD 30), morphological and behavioral effects, posthatch survival and overall survival. Specific analysis of various concentrations of the substance the test media and the controls was carried out via HPLC-DAD. The test media were sampled and analyzed prior to exposure on days -1 and during the exposure on study days 0, 7, 15, 22 and 28. The measured concentrations of replicates and test media on study days 0 to 28 were in the range of 81 to 104% of the nominal concentrations. The DMSO stock solutions were sampled and analyzed from freshly prepared and corresponding 7 days aged stock solution. All effect values are given based on the nominal concentrations of the test item.

The results of the parameters hatching success, fry growth (expressed as weight and length measurement at PHD 30), post-hatch survival and overall survival were checked for statistically significant differences. No statistically significant difference was detected between the dilution water control and the solvent control for all parameters (hatching success, fry growth expressed as length or weight on PHD 30, post-hatch survival and overall survival). Therefore, both controls were pooled for statistical analysis.

The test item caused significant effects on Zebrafish in an early life stage test, 30 days post hatch. For the parameter hatch, the NOEC was 10.0 mg/l. Therefore, the respective LOEC was determined to be > 10.0 mg/l. For the parameters post hatch survival and overall survival, the NOECs were 1.25 and 2.50 mg/l, respectively. Therefore, the respective LOECs were determined to be 2.50 and 5.00 mg/l. For the parameter fry growth (expressed as length and fresh weight) the NOECs were < 0.625 mg/l (length) and 0.625 mg/l (weight). Therefore, the LOECs for length and weight were determined to be 0.625 and 1.25 mg/l, respectively.