Disodium [3-[(4,5-dihydro-3-methyl-5-oxo-1-phenyl-1H-pyrazol-4-yl)azo]-4-hydroxybenzenesulphonato(3-)][1-[[2-hydroxy-5-(phenylazo)phenyl]azo]-2-naphtholato(2-)]chromate(2-)

Endpoint summary

Description of key information

An acute fish toxicity test was performed following a guideline equivalent or similar to OECD test guideline 203 using Zebra fish. Fish were exposed to FAT 21095 for 96 h to determine the TL values. The TL50 in the acute fish toxicity test was determined to be 3.83 mg/l at 48 hours and 3.11 mg/l after 96 hours exposure time. The acute toxicity test on Daphnia magna (Daphnia magna Straus 1820) was performed on FAT 21095/C according to the 92/69/EEC C.2 Acute toxicity for Daphnia method. In a static assay 20 daphnids (0-24 hours old) were exposed to nominal concentrations of 0.91, 2.0, 4.4, 9.6, 21 and 46 mg/l respectively. The EC50 of FAT 21095/C in Daphnia magna was determined to 15.6 mg/l (24 hrs) and 57 mg/l (EC50 48 hrs). Testing FAT 21095 for acute toxicity assessment in algae was technically not feasible. The test material FAT 21095 is a dark colored dye which when mixed in test medium will impart dark color. Due to light absorption, colored substances such as dyes can inhibit algal growth, which is not the result of a toxic action. This shading effect can confound measures of chemical toxicity and thus impair the risk assessment. In an effort to avoid this problem Lemna gibba (Duckweed) Growth Inhibition test (Static) is conducted. In a GLP compliant Lemna gibba (Duckweed) Growth Inhibition test performed in accordance to OECD guideline 221. Lemna gibba (Duckweed) were exposed to the test item (FAT 21095/D TE) at different test concentrations with 0.05, 0.15, 0.45, 1.35, 4.05 and 12.15 mg/L. Frond Numbers: From the average specific growth rate recorded with the different test concentrations with, 0.05, 0.15, 0.45, 1.35, 4.05 and 12.15 mg/L the test concentration that inhibited 50 % growth (ErC50) was calculated as 8.18 mg/L with upper confidence limits of 8.61 mg/L and lower confidence limits of 7.78 mg/L. The percent inhibition on the average specific growth rate on day ‘7’ for the test concentrations of 0.05, 0.15, 0.45, 1.35, 4.05 and 12.15 mg/L, was calculated as 0.09 %, 0.13%, 2.68 %, 5.66 %, 25.35 % and 67.95 %, respectively. From the yield recorded with the different test concentrations with, 0.05, 0.15, 0.45, 1.35, 4.05 and 12.15 mg/L the concentration that inhibited 50 % yield (EyC50) was calculated as 3.77 mg/L with upper confidence limits of 3.95 mg/L and lower confidence limits of 3.59 mg/L. The percent inhibition on the yield on day ‘7’ for the test concentrations of 0.05, 0.15, 0.45, 1.35, 4.05 and 12.15 mg/L was calculated as 0.28%, 0.42 %, 8.20 % 16.55 %, 56.29 % and 92 %, respectively. The no observed effect concentration (NOEC) was calculated as 0.15 mg/L and the low observed effect concentration (LOEC) was calculated as 0.45 mg/L respectively. Frond Dry Weight: From the average specific growth rate recorded with the test concentrations with 0.05, 0.15, 0.45, 1.35, 4.05 and 12.15 mg/L, the concentration that inhibited 50% growth (ErC50) was calculated as 6.89 mg/L with upper confidence limits of 7.25 mg/L and lower confidence limits of 6.54 mg/L. The percent inhibition on the average growth rate on day ‘7’ for the concentration of 0.05, 0.15, 0.45, 1.35, 4.05 and 12.15 mg/L was calculated as 0.99 %, 1.43 %, 5.28 %, 7.34 %, 22.71 % and 78.67 %, respectively. From the yield recorded with the test concentrations viz., 0.05, 0.15, 0.45, 1.35, 4.05 and 12.15 mg/L the concentration that inhibited 50% yield (EyC50) was calculated as 2.91mg/L with upper confidence limits of 3.08 mg/L and lower confidence limits of 2.76 mg/L. The percent inhibition on the yield on day ‘7’ for the test concentrations of 0.05, 0.15, 0.45, 1.35, 4.05 and 12.15 mg/L was calculated as 3.38 %, 4.83 %, 16.57 %, 22.30 %, 54.55 % and 96.04 %, respectively. The no observed effect concentration (NOEC) was calculated as 0.15 mg/L and the low observed effect concentration (LOEC) was calculated as 0.45 mg/L respectively. Activated sludge was exposed to FAT 21095/A to assess the toxicity to microorganisms. About 100 ml of the underrun of a STP is taken and filtered through a sterile filter. Subsequently this filtrate is used to prepare the following dilutions. The toxicity to activated sludge for FAT 21095/A was found to be greater than 300 mg/L. Based on the values from the acute aquatic tests the test substance FAT 21095 can be considered as toxic to aquatic animals.