m-(4,5-dihydro-5-imino-3-methyl-1H-pyrazol-1-yl)benzenesulphonic acid

Endpoint summary

Description of key information

Short-term toxicity to aquatic invertebrates

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the closest read across substances, the toxicity to aquatic invertebrate was predicted 3-(5-imino-3-methyl-4,5-dihydro-1H-pyrazol-1-yl)benzene-1-sulfonic acid (CAS: 68083-38-5). EC50 mobility value was estimated to be 170.4467 mg/l for Daphnia magna for 48 hrs duration. It was concluded that 3-(5-imino-3-methyl-4,5-dihydro-1H-pyrazol-1-yl)benzene-1-sulfonic acid (CAS: 68083-38-5) was likely to be not toxic to aquatic invertebrate.

Toxicity to aquatic algae and cyanobacteria

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the closest read across substances, the toxicity to aquatic algae was predicted 3-(5-imino-3-methyl-4,5-dihydro-1H-pyrazol-1-yl)benzene-1-sulfonic acid (CAS: 68083-38-5). EC50 growth rate value was estimated to be 179.348 mg/l for Pseudokirchneriella subcapitata for 72 hrs duration. It was concluded that 3-(5-imino-3-methyl-4,5-dihydro-1H-pyrazol-1-yl)benzene-1-sulfonic acid (CAS: 68083-38-5) was likely to be not toxic to aquatic algae.

Additional information

Short-term toxicity to aquatic invertebrates

Following studies of target chemical and structurally similar read across includes predicted data and experimental data to conclude the toxicity extent of m-(4,5-dihydro-5-imino-3-methyl-1H-pyrazol-1-yl)benzenesulphonic acid (CAS no. 68083 -38 -5) towards invertebrate is summarized as follows:

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the closest read across substances, the toxicity to aquatic invertebrate was predicted 3-(5-imino-3-methyl-4,5-dihydro-1H-pyrazol-1-yl)benzene-1-sulfonic acid (CAS: 68083-38-5). EC50 mobility value was estimated to be 170.4467 mg/l for Daphnia magna for 48 hrs duration. It was concluded that 3-(5-imino-3-methyl-4,5-dihydro-1H-pyrazol-1-yl)benzene-1-sulfonic acid (CAS: 68083-38-5) was likely to be not toxic to aquatic invertebrate.

The above predicted data of target chemical is supported by the experimental study of structurally similar read across 6-aminonaphthalene- 2-sulphonic acid (CAS No. 93-00-5) from the experimental UERL lab report 2017, suggests that theDaphnia sp., Acute Immobilization Test according to OECD Guideline 202 was conducted for 6-aminonaphthalene-2-sulphonic acid (CAS No.93-00-5) to assess the toxic effects of the test compound on the test Daphnids. Beaker containing 20ml of media with 10 Daphinds. A semi-static procedure was used for the study. The nominal concentration selected for the experiment was 100 mg/L and test Daphnids were exposed to this concentration for 48hours. The Effective concentrations EC50 was found to be >100 mg/L.

Thus, according to the CLP Criteria for aquatic classification of thesubstance, it is concluded that 6-aminonaphthalene- 2-sulphonic acid (CAS No. 93-00-5) does not exhibit toxicity to aquatic invertebrate (daphnia magna) andtherefore it cannot be classified as hazardous substance.

EC50 (48 hours) Experimental = >100 mg/L.

Another supporting experimental study for the structurally similar read across Sulfanilic acid (121-57-3) from the publication chemosphere 1994, also suggests that the To study the effects of 4-aminobenzenesulfonic acid on aquatic invertebrate test was carried out for 24 hr.

The effective concentration EC50 value for short term toxicity to aquatic invertebrates for Sulfanilic acid(121-57-3) in 24 hrs is109.13 mg/l. It can be concluded from the value that the Sulphanilic acid is not toxic to the aquatic invertebrate.Based on the result, Sulfanilic acid (121-57-3) was considered as :not classified" as per the CLP regulations.

Thus based on the effect concentrations which is in the range >100 mg/l to 170.442 mg/l give the conclusion that test substance m-(4,5-dihydro-5-imino-3-methyl-1H-pyrazol-1-yl)benzenesulphonic acid (CAS no. 68083 -38 -5) was likely to be not toxic to aquatic invertebrate at environmentally relevant concentrations and can be considered to be “not classified” as per the CLP classification criteria.

Toxicity to aquatic algae and cyanobacteria

Following studies of target chemical and structurally similar read across includes predicted data and experimental data to conclude the toxicity extent of m-(4,5-dihydro-5-imino-3-methyl-1H-pyrazol-1-yl)benzenesulphonic acid (CAS no. 68083 -38 -5) towards algae is summarized as follows:

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the closest read across substances, the toxicity to aquatic algae was predicted 3-(5-imino-3-methyl-4,5-dihydro-1H-pyrazol-1-yl)benzene-1-sulfonic acid (CAS: 68083-38-5). EC50 growth rate value was estimated to be 179.348 mg/l for Pseudokirchneriella subcapitata for 72 hrs duration. It was concluded that 3-(5-imino-3-methyl-4,5-dihydro-1H-pyrazol-1-yl)benzene-1-sulfonic acid (CAS: 68083-38-5) was likely to be not toxic to aquatic algae.

The above predicted data of target chemical is supported by the experimental study of structurally similar read across 6-aminonaphthalene- 2-sulphonic acid (CAS No. 93-00-5) from the experimental UERL lab report 2016, suggests that theeffect of test item 6- aminonaphthalene-2-sulphonic acid, CAS No. 93-00-5 was studied on the growth of fresh water green alga Chlorella vulgaris. The study was conducted following OECD guideline 201- Alga, growth inhibition test. The test concentration chosen for the study were 6.25 mg/L,12.5 mg/L,25 mg/L,50 mg/L,100 mg/L,200 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 >200 mg/L. Thus, based on this EC50 value and according to CLP Criteria for aquatic classification of the substance, it is concluded that 6-aminonaphthalene-2-sulphonic acid (CAS No.- 93-00-5) does not exhibits toxicity to aquatic algae (Chlorella vulgaris)

Another supporting experimental study for the structurally similar read across4-amino-3-methylbenzene- sulfonic acid (cas: 98 -33 -9) also suggests that the

Freshwater algal growth inhibition test was carried out on Desmodesmus subspicatus with the substance 4-amino-3- methylbenzenesul- fonic acid according to OECD Guideline 201.The test substance was dissolved in OECD growth medium and tested at the concentrations 0, 0, 30, 45, 67, 100, 150 mg/L. Effects on the growth rate of the organism were studied. The median effective concentration (EC50) for the test substance 4-amino-3-methylbenzene- sulfonic acid, in Desmodesmus subspicatus was determined to be 110.6 mg/L

This value indicates that the substance is likely to be non-hazardous to aquatic algae and cannot be classified as per the CLP criteria.

Thus based on the effect concentrations which is in the range 110.6 mg/l to >200 mg/l give the conclusion that test substance m-(4,5-dihydro-5-imino-3-methyl-1H-pyrazol-1-yl)benzenesulphonic acid (CAS no. 68083 -38 -5) was likely to be not toxic to aquatic invertebrate at environmentally relevant concentrations and can be considered to be “not classified” as per the CLP classification criteria.