Tetrasodium [μ-[3-[[2-amino-5-hydroxy-6-[(2-hydroxy-5-nitro-3-sulphophenyl)azo]-7-sulpho-1-naphthyl]azo]-2-hydroxy-5-sulphobenzoato(8-)]]dichromate(4-)

Endpoint summary

Description of key information

The test item concentrations in the below described studies according to OECD guidelines 202, 203 and 221 were determined analytically in duplicate from the freshly prepared test media and at the end of the tests respectively by HPLC/UV detection. The validity criteria for a concentration range of 1 – 150 mg/L have been met using calibration curves/linear regression. It has been demonstrated, that the measured test item concentrations have been maintained within ± 20 % of the nominal concentrations.

Therefore, all reported results refer to nominal concentrations.

short-term toxicity to fish

Juvenile Zebrafish were exposed in a 96 h static test according to OECD guideline 203 to aqueous test media containing the test item at various concentrations. A full dose response study - 100, 45.5, 20.7, 9.4 and 4.3 mg/L test item – was performed. The study encompassed 6 treatment groups (5 dose rates and a control) each containing 7 individuals. The recorded effects were mortality and sublethal effects on the fish.

In the control and at the concentrations up to 4.3 mg test item/L, all fish survived until the end of the experiment and no signs of intoxication occurred. At 9.4 mg/L one fish died and at 20.7 mg/L three fish died after 96 hours. At 45.5 mg/L two fish died and at 100 mg test item/L three fish died after 96 hours. Based on these test results the following dose descriptors were determined:

LC50 (96 h) > 100 mg/L

LOEC (96 h) = 20.7 mg/L

NOEC (96 h) = 9.4 mg/L

short-term toxicity to aquatic invertebrates

The toxic effect of the test item to Daphnia magna was assessed in a 48 h static test according to OECD guideline 202. A full dose response study - 100, 45.5, 20.7, 9.4 and 4.3 mg/L test item – was performed. The study encompassed 6 treatment groups (5 dose rates and a control) each containing 20 individuals. The mobility of the Daphnia was determined by visual observation after 24 and 48 hours.

After 48 hours of exposure no immobilisation of the test animals was observed in the control and up to and including the test item concentration of 45.5 mg/L. At 100 mg test item/L two animals were immobile. Based on the test results the following dose descriptors were laid down:

EC50 (48 h) > 100 mg/L

NOEC (48) ≥100 mg/L

toxicity to aquatic plants other than algae

The inhibitory effect of the test item on the growth of the freshwater aquatic plantLemna gibbawas determined according to OECD guideline 221. Cultures ofLemna gibbawere exposed in a semi-static test to the test item concentrations 100, 32, 10, 3.2 and 1.0 mg/L. The inhibition of growth in relation to control cultures was determined over a test period of 7 days.

This study encompassed 6 treatment groups (5 dose rates of the test item and a control) with three replicates per test concentration and control. At test start 12 fronds were introduced in each replicate. Beside other parameters growth rates based on frond numbers were determined. The following results were reported:

 

EC50 (7 d) > 100 mg/L

EC20 (7 d) = 17.1 mg/L

EC10 (7 d) = 3.14 mg/L

NOEC (7 d) = 1.0 mg/L

toxicity to microorganisms

A Respiration Inhibition Test with activated sludge according to OECD guideline 209 was performed with the test item. The test was carried out for a period of 3 hours under static conditions with the nominal limit concentration of 1000 mg/L. The mean respiration rate of activated sludge treated with the test item differed from the mean respiration rate of the control by 11 %. Therefore, the test item had no toxic effects on respiration activity of activated sludge: NOEC > 1000 mg/L.

The test of the positive control 3,5-dichlorophenol (EC50 = 2.6 mg/L) confirmed the validity of the study (EC50 within the range 2 – 25 mg/L).