3-methylsulphanilic acid

Endpoint summary

Description of key information

Short-term toxicity to fish:

In acute toxicity to fish test been performed to evaluate the toxicological effects of chemical 4-Amino-m-toluenesulfonic acid in fish (Gambusia affinis).The chemical was exposed to Gambusia affinis fish with dose concentration of 180,320,560,1000 mg/L with exposure duration of 24,48 and 96 hrs.The mortality was observed in the fish, at 560 and 1000 mg/L all animals were dead in 6 hrs only.Hence,the median lethal concentration (LC50) value was observed to be 375 mg/L, 410 mg/L and 425 mg/L for exposure period of  96,48 and 24-hrs respectively when tested in Gambusia affinis fish based on mortality effect. Based on this value it can be concluded that the substance 4-amino-3-methylbenzene sulfonic acid is considered to be non-toxic to fish and can be considered to be not classified as per the CLP classification criteria.

Short term toxicity to aquatic invertebrates:

Aim of the study was to determe the inhibition of the mobility of daphnids was carried out with the substance 4-amino-m-toluenesulfonic acid. Test was performed according to OECD Guideline 202. The stock solution 150 mg/l was prepared by dissolving white powder in reconstituted water. Solution kept in ultrasonic bath for 20 min. Test solutions of required concentrationas were prepared by mixing the stock solution of the test sample with reconstituted test water and was tested at the nominal concentrations 30, 45, 67, 100, 150 mg/l . Effects on immobilisation were observed for 48 hours. The median effective concentration (EC50) for the test substance 4-amino-m-toluenesulfonic acid, in Daphnia magna was determined to be 74.9 mg/L on the basis of mobiity inhibition effects in a 48 hour study. This value indicates that the substance is likely to be hazardous to aquatic invertebrates and can be classified as aquatic chronic 3 as per the CLP criteria.

Toxicity to aquatic algae and cyanobacteria:

Freshwater algal growth inhibition test was carried out on Desmodesmus subspicatus with the substance 4-amino-3- methylbenzenesulfonic 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. 

 

Additional information

Short-term toxicity to fish:

Four different studies from experimental study using peer reviewed journal and validated predicted model for short term fish toxicity endpoint of target chemical 4-amino-3-methylbenzenesulfonic acid (Cas no. 98-33-9) with relevant read across chemicals which is structurally similar to target chemical are summarized as followed:

First experimental study suggest acute toxicity to fish test been performed to evaluate the toxicological effects of chemical 4-Amino-m-toluenesulfonic acid in fish (Gambusia affinis).The chemical was exposed to Gambusia affinis fish with dose concentration of 180,320,560,1000 mg/L with exposure duration of 24,48 and 96 hrs.The mortality was observed in the fish, at 560 and 1000 mg/L all animals were dead in 6 hrs only.Hence,the median lethal concentration (LC50) value was observed to be 375 mg/L, 410 mg/L and 425 mg/L for exposure period of  96,48 and 24-hrs respectively when tested in Gambusia affinis fish based on mortality effect.

Other predicted data gives assistance to above experimental result i.e predicted model by EPI Suite ECOSAR version 1.10 indicate the 96 hours LC50 was estimated to be 230000 mg/l on Fish for substance 4-amino-3-methylbenzenesulfonic acid (Cas no. 98-33-9) on the basis of mortality effects. 

Above both results for target chemical supported by experimental study of read across 4-aminobenzenesulfonic acid (Cas no. 121-57-3) which suggest Toxic effects of test substance 4-amino-benzenesulfonic acid was determined on various fish species like Leuciscus idus, Bruchydunio rerio,Salmo gaidneri, Pimephales promelas, Lepomis macrochirus, Poecilia reticulate for 48 and 96 hrs in static condition and in fresh water. During experiment the lethal concentrations i.e LC0 and LC50 values were found to be 1000 mg/l and 100.4 mg/l respectively. (Chemosphere, Vol. 28, No. 12, pp. 2203.2236, 1994)

Another study for one more structurally similar read across chemical 2-amino-5-methylbenzenesulfonic acid (Cas no. 88-44-8) indicate the toxic effects of test substance 4-aminotoluene-3-sulphonic acid was examined on fish Oryzias latipes for 48 hrs. During experiment the lethal concentration (LC50) was found to be 480 mg/l on the basis of mortality effects.

All available median lethal concentration (LC50) values for fish toxicity in acute exposure is in the range of 375-230000 mg/l which gives common conclusion as target chemical 4-amino-3-methylbenzenesulfonic acid (Cas no. 98-33-9) is considered to be non-toxic to fish and can be considered to be not classified for aquatic environment as per the CLP classification criteria.

Short term toxicity to aquatic invertebrates:

Aim of the study was to determe the inhibition of the mobility of daphnids was carried out with the substance 4-amino-m-toluenesulfonic acid. Test was performed according to OECD Guideline 202. The stock solution 150 mg/l was prepared by dissolving white powder in reconstituted water. Solution kept in ultrasonic bath for 20 min. Test solutions of required concentrationas were prepared by mixing the stock solution of the test sample with reconstituted test water and was tested at the nominal concentrations 30, 45, 67, 100, 150 mg/l . Effects on immobilisation were observed for 48 hours. The median effective concentration (EC50) for the test substance 4-amino-m-toluenesulfonic acid, in Daphnia magna was determined to be 74.9 mg/L on the basis of mobiity inhibition effects in a 48 hour study. This value indicates that the substance is likely to be hazardous to aquatic invertebrates and can be classified as aquatic chronic 3 as per the CLP criteria.

Toxicity to aquatic algae and cyanobacteria:

Summarized experimental studies for the 4 -Amino-3 -methylbenzenesulfonic acid (CAS no. 98 -33 -9) from ABITEC report and also which is supported further by total 3 supporting studies (from authoritative database, peer reviewed journal and secondary source) for its closest read across substance with logKow as the primary descriptor were reviewed for the toxicity to aquatic algae and cyanobacteria end point which are summarized as below:

 

In the first key study from ABITEC report 2017, Freshwater algal growth inhibition test was carried out on Desmodesmus subspicatus with the substance 4-amino-3- methylbenzenesulfonic 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. 

 

In a prediction done using the EPI Suite ECOSAR version 1.10 (2017), short term toxicity on green algae was predicted for test substance4-Amino-3-methylbenzenesulfonic acid(CAS no. 98-33-9).The 96 hours EC50 was estimated to be 18195.3 mg/l on green algae for substance 4 -amino-3 -methylbenzenesulfonic acid (CAS no. 98 -33 -9) with growth inhibition effects.Thus, based on this value, it can be concluded that the test chemical 4 -amino-3 -methylbenzenesulfonic acid can be considered as non-toxic to aquatic organisms and thus can be considered to be not classified as per the CLP classification criteria.

 

Another prediction for short term toxicity on green algae was predicted for test substance 4-amino-3-methylbenzenesulfonic acid (CAS: 98 -33 -9) using the three different models i.e, Battery, Leadscope and SciQSAR used within Danish QSAR database (Danish QSAR database, 2017). The average EC50 value was given by the third model i.e, Battery model. On the basis of effects observed in a static freshwater system, the effect concentration EC50 value for the substance 4-amino-3-methylbenzenesulfonic acid is estimated to be 966.50 mg/l for Pseudokirchneriella subcapitata during 72 hr exposure duration. 

 

In a supporting study of read across chemical Aniline (CAS no. 62 -53 -3) from authoritative database (J-CHECK, 2016), short term toxicity to green algae study was carried out for 72 hrs. The study was based on the effects of the test compound Aniline (CAS no. 62 -53 -3) on green algae in a static fresh water system. Based on effect on growth rate of the test organism green algae, the 72 hr EC50 and NOEC value was determined to be 110 and 3.7 mg/l, and on the basis of areas under the growth curves, the 72 hr EC50 and NOEC value was determined to be 41 and 11 mg/l, respectively.

 

For the same read across chemical Aniline (CAS no. 62 -53 -3), short term toxicity to Chlorella pyrenoidosa study was carried out for 72 hrs (Enaut Urrestarazu Ramos et. al; 1999). The study was performed according to OECD Guideline 201 (Alga, Growth Inhibition Test). The study was based on the effects of the read across compound Aniline on green algae in a static fresh water system at a temperature of 22ᵒC and pH. Chlorella pyrenoidosa was used as test organism provided by H. Oldersma from TNO (Delft, The Netherlands). The algae were cultured in Miller’s solution using a 100 ml bottle, which was renewed (1:5) at least once a week. The algal cultures were incubated on top of a series of TL tubes, and were shaken by a microplate shaker at 300 rpm. Total 5 test concentrations was used for the study. Stock solutions were prepared directly in the culture medium, and were stirred for at least 24 h. The stock solutions were used to prepare fresh test solutions by dilution with medium. Tests were performed in 40 ml vials containing 20 ml solution, to which 0.5 ml inoculum (approximately 2 × 106cells/ml) was added. The pH, temperature and actual concentration of each flask were measured at the beginning and the end of the test. The algae population was determined at 0, 6, 24, 48 and 72 h, respectively. The population density versus time in each vial was fitted to the exponential growth function, using the GRAPHPAD PRISM statistical program, version 2.01 (GraphPad Software, San Diego, CA, USA). Partial effect concentrations (EC10 and EC50) were determined by fitting the relative growth rate as a function of the test concentration using the Weibull function. Curve fitting was also performed using the above-mentioned GRAPHPAD PRISM statistical program. NOECs and LOECs were calculated using the Environmental Protection Agency (EPA) methods implanted in the TOXCALC toxicity data analysis software, version 5.0.9 (TidePole Software, USA). The significance levels used wereα =0.01 for the auxiliary tests andα =0.05 for the hypothesis tests. NECs were estimated using DEBTOX, version 1.6 computer program. Based on effect on growth rate of the test organism green algae, the 72 hr NOEC, LOEC and EC50 value was determined to be 90, 156 and 175 mg/l, respectively.

 

Additional supporting study of short term toxicity to Scenedesmus subspicatus (green algae) study for read across compound 4 -aminobenzenesulfonic acid (CAS no. 121 -57 -3) was carried out for 72 hrs in a static fresh water system (High Production Volume (HPV) Challenge Program; 2016). The study was performed according to other guideline DIN 38412 Part 9, 1992. Scenedesmus subspicatus was used as a test organism. Based on effect on growth rate of the test organism Scenedesmus subspicatus (green algae), the 72 hr EC10 and EC50 value was determined to be 2.7 and 375 mg/l, respectively.

 

Thus, based on the overall reported results for target chemical 4-Amino-3-methylbenzenesulfonic acid (from ABITEC report, EPI suite and Danish QSAR database, 2017) and for its read across substance (from authoritative database, peer reviewed journal and secondary source), it can be concluded that the test substance Amino-3-methylbenzenesulfonic acid can be considered as non-toxic to aquatic environment and can be considered to be not classified as per the CLP classification criteria.

Based on the studies on aquatic algae and fish chemical was nontoxic and not classified, but as the chemical was proved as toxic and classified as a toxic to aquatic invertebrates, so on that basis 4-Amino-3-methylbenzenesulfonic acid from ABITEC report, was concluded as a toxic and can be consider to be classified as aquatic chronic 3 as per the CLP classification criteria.