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Short-term toxicity to aquatic invertebrates

From prediction model based estimation and raed across data for the short term aquatic invertebrates toxicity of the test compound tetrasodium 1-acetamido-2-hydroxy-3-(4-((4-sulphonatophenylazo)-7-sulphonato-1-naphthylazo)) naphthalene-4,6-disulphonate (CAS No 2519-30-4). The summary is as below:

 

The effective concentration (EC50) value based on QSAR prediction of tetrasodium 1-acetamido-2-hydroxy-3-(4-((4-sulphonatophenylazo)-7-sulphonato-1-naphthylazo))naphthalene-4,6-disulphonate (CAS No 2519-30-4) in aquatic invertebrate (daphnia magna) in 48 hrs was estimate to be 1334.55 mg/l on the basis of intoxication effects.

Therefore the EC50 was considered to be1334.55 mg/lfortetrasodium 1-acetamido-2-hydroxy-3-(4-((4-sulphonatophenylazo)-7-sulphonato-1-naphthylazo))naphthalene-4,6-disulphonateand it is readily biodegradable in nature indicating that test substance not likely to exhibit toxicity to aquatic invertebrate as per the CLP criteria.

 

From read across data for Acid Red 1 (Red 2G) (Sergiu Adrian Chicu and et.al. 2014),Structure-toxicity relationships for Acid Red 1 were developed usingHydractinia echinata(H. echinata) as model species.Test chemical was purchased from leading chemical suppliers from their catalogues. Colonies ofH. echinata(Biologische Anstalt, Helgoland, Germany) were used to obtain eggs and larvae. The culture medium was artificial seawater (980 mosmol, pH 8.2, 18°C). In laboratory an artificial metamorphosis can be synchronically started by the introduction of Cs+ ions or by using seawater without Mg2+ ions; it then lasts only 24 h. Under the action of external stimulus of Cs+ ions or Cs+ ions together with the tested compounds, one part of larvae further lives as such and another one is metamorphosized to the polyp form. The evaluation of the influence of the tested substance is very clear this way, the proposed method being based on this aspect.H. echinatalarvae were exposed to seawater containing Cs+ and simultaneously one of the test substances for 3 h. The percentage of animals that underwent metamorphosis (development into polyps) was determined after 24 h. During the following days the frequency of inductions did not further increase. A concentration of inducers was chosen which caused about three half to three quarters of the larvae to metamorphose in order to have conditions which are highly sensitive against an inhibitory influence. The concentration of the test substances (expressed in mol/L) was varied in such a way that we were able to determine the concentration at which the frequency of induction was reduced by 50% with respect to a control. This concentration was termed MRC50 (forMetamorphosisReductionConcentration) and is similar to the effective EC50 concentration that gives half maximal effective response. The logarithm of the reciprocal value (log1/MRC50) values, the average (C) concentrations of these values was calculated for the test chemical. The MRC50 value calculations result from the graphical representation of the metamorphosis variation, M (%), (Y axis) function of the xenobiotic’s concentration (mol/L) (X axis), where the metamorphosis decreases with the rise of the xenobiotic’s concentration. Thus, the MRC50 value represents the xenobiotic’s concentration (mol/L) necessary for a 50% decrease of metamorphosis, with respect to control. The MRC 50 value forHydractinia echinataafter 3 hours of exposure to test chemical was determined to be 111.45026 mg/L. The test chemical can be considered non- toxic toHydractinia echinataunder the test conditions

 

Thus the chemical is not expected to exhibit aquatic toxicity as per the CLP criteria.

 

 

Toxicity to aquatic algae and cyanobacteria:

The effect of test item tetrasodium 1-acetamido-2-hydroxy-3-(4-((4-sulphonatophenylazo)-7-sulphonato-1-naphthylazo))naphthalene-4,6-disulphonate, CAS No. 2519-30-4 was studied on the growth of fresh water green algaChlorella vulgaris.The study was conducted following OECD guideline 201- Alga, growth inhibition test. The test concentration chosen for the study were 0.3 mg/L, 0.96 mg/L, 3.072 mg/L, 9.830 mg/L, 31.457 mg/L and 100.663 mg/L. The test concentrations were prepared using stock solution of the test item using mineral media. The green alga was exposed to the test concentration for a period of 72 hours to observe average specific growth rate and % growth inhibition under the effect of the test item. EC50 calculated graphically through probit analysis was observed to be 24.342 mg/L.

On the basis of avove reported information, the test substance is likely to result in toxicity category II to aquatic algae as per the CLP criteria.