7-acetamido-4-hydroxy-3-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]naphthalene-2-sulphonic acid, sodium salt

Endpoint summary

Description of key information

Short-term toxicity to fish

The 96h LC50 for the read across substance (structural analogue 01 as lithium salt) or its hydrolysis product (structural analogue 01 -OH) was determined according to OECD 203 to be greater than 500 mg/L.

 

Short-term toxicity to aquatic invertebrates

The 48h-EC50 for the read across substance (structural analogue 02) was determined according to OECD 202 to be 117.4 mg/L.

 

Toxicity to algae and cyanobacteria

The influence of the test substance structural analogue 01-OH on the growth of the green alga Scenedesmus subspicatus Chodat was investigated in a 72-hour static test according to the OECD Guideline No. 201 (1984). After 72 hours the EC50 was determined to be greater than 320 mg/L (nominal value) and the NOEC was determined to be 3.2 mg/L.

Toxicity to microorganisms

The toxicity of Reactive Orange 72/78 on bacteria ("bacterial toxicity") was investigated in the oxygen-consumption inhibition test ("Robra test") with activated sludge as inoculum. After 3 hours the NOEC and the EC50 were determined to be greater than 1000 mg/L.

Additional information

The effects of the test substance (structural analogue 01 as lithium salt) or its hydrolysis product (structural analogue 01 -OH) on the aquatic compartment have been tested for 96 hours in Zebrafish (Danio rerio) according to OECD 203. After administration of the highest concentration of 500 mg/L no mortality and no adverse effects were observed. The LC50 after 48 and 96 hours is more than 500 mg/L for both compounds. The test substances were stable throughout the experimental period.

An acute toxicity study with the structural analogue 01 as lithium salt was carried-out with Daphnia magna according to DIN 38 412 "Daphnien-Kurzzeittest" (equal to OECD 202) for 24 hours. Daphnids were exposed to the test substance at concentrations of 88.4, 125.6, 176.8, 250, 353.6 and 500 mg/L and a negative control (0 mg/L). Observations were made on the immobilisation rate after 24 h of exposure. The EC0 of the test item was determined to be 88.4 mg/L, the EC50 355 mg/L, and the EC100 600 mg/L.

 

Another study to assess the acute toxicity of the test substance structural analogue (SA02) to Daphnia magna (water flea) over 48 h was performed under static conditions. The study was conducted in accordance with OECD Guideline 202 and EU Method C.2. in compliance with GLP. Daphnids were exposed to the test substance at concentrations of 22, 50, 100, 220 and 500 mg/L and a negative control (0 mg/L).The substance concentration was determined in all tested groups at the test start and after 48 h of exposure. Observations were made on the immobilisation rate after 24 and 48 h of exposure. All tested concentrations were present as clear orange solutions. The values determined were in a range of ± 20 % of the theoretical value. The 24 and 48 h EC50values were determined to be 362.8 and 117.4 mg/L, respectively. In the control group no immobility was observed. Immobility was observed at 50, 100, 220 and 500 mg/L. The 22 mg/L group showed no effect in comparison to the negative control. Under the test conditions, the 48 h EC50 value of the test substance was determined to be 117.4 mg/L.

 

The influence of the test substance structural analogue 01-OH on the growth of the green alga Scenedesmus subspicatus Chodat was investigated in a 72-hour static test according to the OECD Guideline No. 201, adopted June 7, 1984. However, the test method was modified to differentiate between a reduced growth of algae due to real toxic effects of the test substance on the algal cells or due to an indirect effect, a reduced algal growth by tight absorption in coloured test solutions. The test was performed in compliance with Good Laboratory Practice Regulations. The nominal test concentrations were 3.2, 10.0, 32.0, 100 and 320 mg test substance/L and a control. All test media down to the lowest test concentration were little to strongly coloured by the test substance. After correction of the total inhibition effect by the filter effect of the dyestuff, the real toxic effect of the test substance on the growth of Scenedesmus subspicatus after the 72 hours exposure period amounted to lower than 50% up to the highest test concentration of 320 mg test substance/L. Consequently, more than 50% of the inhibition effect, determined in the usual algal growth inhibition test was caused by the filter effect of the dyestuff. In conclusion, this modified algal test has demonstrated that the observed growth inhibition effect of the test substance on Scenedesmus subspicatus was caused in a high degree (> 50 %) due to the indirect effect, the light absorption in the coloured test solutions. Thus, the 72-hours EµC 50 and EbC 50 could be determined to be clearly higher than 320 mg test substance/L when based on the real toxic effect.

 

The toxicity of Reactive Orange 72/78 on bacteria ("bacterial toxicity") was investigated in the oxygen-consumption inhibition test ("Robra test") with activated sludge as inoculum. The provision of the inhibition rate of oxygen consumption after 3 hours of exposure to the test item on bacteria test gave the following results: 

Median inhibitory concentration, EC50: >> 1000 mg/L

NOEC, EC20 : >1000 mg/L

EC 80: >> 1000 mg/L