1-(2-methyl-4-(2-methylphenylazo)phenylazo)-2-naphthol

Endpoint summary

Description of key information

Short term toxicity to fish:

In accordance with column 2 of Annex VIII of the REACH regulation, testing for this end point is considered scientifically not necessary since there are mitigating factors indicating that aquatic toxicity is unlikely to occur as the test chemical is highly insoluble (solubility: 0.023 mg/L at 25° C) in water and also having the partition coefficient value ranging from 6.66 to 6.87, respectively. Thus, test chemical can be considered to be hydrophobic in nature.

Short term toxicity to aquatic invertebrates:

Determination of the inhibition of the mobility of daphnids was carried out with the substance 1-(2-Methyl-4-(2-methylphenylazo)phenylazo)-2-naphthol. Test was conducted according to OECD Guideline 202 (Experimental study report, 2017). The stock solution 2 g/L was prepared by dissolving brown powder in acetone. Test solutions of required concentrationas were prepared by mixing the stock solution of the test sample with reconstituted test water. The test substance was tested at the concentrations 0, 0, 0.6, 1.2, 2.5, 5, 10 mg/l nominal concentrations. Effects on immobilisation were observed for 48 hours. The median effective concentration (EC50) for the test substance, 1 -(2 -Methyl-4 -(2 -methylphenylazo)phenylazo)-2 -naphthol, in Daphnia magna was determined to be 3.9 mg/L. This value indicates that the substance is likely to be hazardous to aquatic algae and can be classified as aquatic chronic 2 as per the CLP criteria. But as the chemical was readily biodegradable in water so on the basis of biodegradability, it can be concluded that the chemical 1 -(2 -Methyl-4 -(2 -methylphenylazo) phenylazo)-2 -naphthol was nontoxic and can be consider to be not classified as per the CLP classification criteria.

Toxicity to aquatic algae and cyanobacteria:

Freshwater algal growth inhibition test was carried out on Desmodesmus subspicatus with the substance 1-(2-Methyl-4-(2-methylphenylazo)phenylazo)-2-naphthol (85 -86 -3) according to OECD Guideline 201 (Experimental study report, 2017). As the test substance was insoluble in water so that the stock solution 2 g/L was prepared by dissolving brown powder in acetone. Test solutions of required concentration were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture. 5x10(3) cells /ml algae culture were use in the study for total exposure period of 72hrs. Test conducted in 50 ml Glass vessel filled with 50 ml of sample volume and tested at the concentrations 0, 0, 1.2, 2.4, 5, 10, 20 mg/l. Effects on the growth rate of the organism were studied. The median effective concentration (EC50) for the test substance, 1 -(2 -Methyl-4 -(2 -methylphenylazo)phenylazo)-2 -naphthol, in Desmodesmus subspicatus was determined to be 153.5 mg/L. This value indicates that the substance is likely to be non-hazardous to aquatic algae and cannot be classified as toxic as per the CLP criteria.

Toxicity to microorganism:

In accordance with column 2 of Annex VIII of the REACH regulation, testing for this end point is considered scientifically not necessary since there are mitigating factors indicating that aquatic toxicity is unlikely to occur as the test chemical is highly insoluble (solubility: 0.023 mg/L at 25° C) in water and also having the partition coefficient value ranging from 6.66 to 6.87, respectively. Thus, test chemical can be considered to be hydrophobic in nature.

 

Additional information

Short term toxicity to fish:

In accordance with column 2 of Annex VIII of the REACH regulation, testing for this end point is considered scientifically not necessary since there are mitigating factors indicating that aquatic toxicity is unlikely to occur as the test chemical is highly insoluble (solubility: 0.023 mg/L at 25° C) in water and also having the partition coefficient value ranging from 6.66 to 6.87, respectively. Thus, test chemical can be considered to be hydrophobic in nature.

Short term toxicity to aquatic invertebrates:

Determination of the inhibition of the mobility of daphnids was carried out with the substance 1-(2-Methyl-4-(2-methylphenylazo)phenylazo)-2-naphthol. Test was conducted according to OECD Guideline 202 (Experimental study report, 2017). The stock solution 2 g/L was prepared by dissolving brown powder in acetone. Test solutions of required concentrationas were prepared by mixing the stock solution of the test sample with reconstituted test water. The test substance was tested at the concentrations 0, 0, 0.6, 1.2, 2.5, 5, 10 mg/l nominal concentrations. Effects on immobilisation were observed for 48 hours. The median effective concentration (EC50) for the test substance, 1 -(2 -Methyl-4 -(2 -methylphenylazo)phenylazo)-2 -naphthol, in Daphnia magna was determined to be 3.9 mg/L. This value indicates that the substance is likely to be hazardous to aquatic algae and can be classified as aquatic chronic 2 as per the CLP criteria. But as the chemical was readily biodegradable in water so on the basis of biodegradability, it can be concluded that the chemical 1 -(2 -Methyl-4 -(2 -methylphenylazo) phenylazo)-2 -naphthol was nontoxic and can be consider to be not classified as per the CLP classification criteria.

Short term toxicity to aquatic invertebrate endpoint can also be considered for waiver as per ccordance with column 2 of Annex VIII of the REACH regulation, testing for this end point is considered scientifically not necessary since there are mitigating factors indicating that aquatic toxicity is unlikely to occur as the test chemical is highly insoluble (solubility: 0.023 mg/L at 25° C) in water and also having the partition coefficient value ranging from 6.66 to 6.87, respectively. Thus, test chemical can be considered to be hydrophobic in nature.

Toxicity to aquatic algae and cyanobacteria:

Freshwater algal growth inhibition test was carried out on Desmodesmus subspicatus with the substance 1-(2-Methyl-4-(2-methylphenylazo)phenylazo)-2-naphthol (85 -86 -3) according to OECD Guideline 201 (Experimental study report, 2017). As the test substance was insoluble in water so that the stock solution 2 g/L was prepared by dissolving brown powder in acetone. Test solutions of required concentration were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture. 5x10(3) cells /ml algae culture were use in the study for total exposure period of 72hrs. Test conducted in 50 ml Glass vessel filled with 50 ml of sample volume and tested at the concentrations 0, 0, 1.2, 2.4, 5, 10, 20 mg/l. Effects on the growth rate of the organism were studied. The median effective concentration (EC50) for the test substance, 1 -(2 -Methyl-4 -(2 -methylphenylazo)phenylazo)-2 -naphthol, in Desmodesmus subspicatus was determined to be 153.5 mg/L. This value indicates that the substance is likely to be non-hazardous to aquatic algae and cannot be classified as toxic as per the CLP criteria.

Toxicity to aquatic algae endpoint can also be considered for waiver as per ccordance with column 2 of Annex VIII of the REACH regulation, testing for this end point is considered scientifically not necessary since there are mitigating factors indicating that aquatic toxicity is unlikely to occur as the test chemical is highly insoluble (solubility: 0.023 mg/L at 25° C) in water and also having the partition coefficient value ranging from 6.66 to 6.87, respectively. Thus, test chemical can be considered to be hydrophobic in nature.

Toxicity to microorganism:

In accordance with column 2 of Annex VIII of the REACH regulation, testing for this end point is considered scientifically not necessary since there are mitigating factors indicating that aquatic toxicity is unlikely to occur as the test chemical is highly insoluble (solubility: 0.023 mg/L at 25° C) in water and also having the partition coefficient value ranging from 6.66 to 6.87, respectively. Thus, test chemical can be considered to be hydrophobic in nature.