3-methylsulphanilic acid

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

21.03.2017 – 24.03.2017, 28.03.2017 - 31.03.2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Experiment test result performed using standard test guideline.

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Principles of method if other than guideline:

Short term toxicity study to algae was performed according to the OECD guideline 201 in a static system.

GLP compliance:

no

Specific details on test material used for the study:

- Name of test material: 4-amino-m-toluenesulfonic acid
- Molecular formula: C7-H9-N-O3-S
- Molecular weight: 187.218 g/mol
- SMILES : O=S(=O)(O)c(ccc(N)c1C)c1
- Substance type: Organic
- Physical state: Solid

Analytical monitoring:

not specified

Details on sampling:

No data available

Vehicle:

not specified

Details on test solutions:

The stock solution (150 mg/L) was prepared by dissolving white powder in OECD growth medium. The solution was kept in ultrasonic bath for 20 min.Test solutions of required concentration were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name:
- Strain: 86.81 SAG
- Source (laboratory, culture collection): Institute of botany of the ASCR
- Initial biomass concentration: 5x10(3) cells /ml
- Method of cultivation: No data available

ACCLIMATION - No data available
- Acclimation period:
- Culturing media and conditions (same as test or not):
- Any deformed or abnormal cells observed:

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Remarks on exposure duration:

±1 hour

Post exposure observation period:

No data available

Hardness:

No data available

Test temperature:

23±2°C

pH:

Test pH varies with the different concentrations: 7.9 - 5
Control 1: 8.3 (changed to 7.9 during test)
Control 2: 8 (changed to 7.8 during test)

Dissolved oxygen:

No data available

Salinity:

No data available

Conductivity:

No data available

Nominal and measured concentrations:

0, 0, 30, 45, 67, 100, 150 mg/l.

Details on test conditions:

TEST SYSTEM
- Test vessel: 50 ml Glass vessel
- Type (delete if not applicable): closed (with air permeable stopper)
- Sample volume: 15 ml
- Initial cells density: 5x10(3) cells/ml
- No. of vessels per concentration (replicates): 3

GROWTH MEDIUM
- Standard medium used: yes

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: Continuous
- Light intensity and quality: 6000-8000 lx

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: microscope with counting chamber Cyrus I or electronic particle counter.
- Other: ErC50 was calculated using non-linear regression by the software Prism 4.0

Reference substance (positive control):

yes

Remarks:

Potassium dichromate (K2Cr2O7)

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

110.6 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% CL: 108.8 - 112.4

Details on results:

No data available

Results with reference substance (positive control):

Results with reference substance valid
- EC50: 0.75 mg/L

Reported statistics and error estimates:

Nonlinear regression by the software prism 4.0.

Validity criteria fulfilled:

not specified

Conclusions:

The median effective concentration (EC50) for the test substance 4-amino-3-methylbenzenesulfonic acid, in Desmodesmus subspicatus was determined to be 110.6 mg/L on the basis of effects on growth rate in a 72 hour study.

Executive summary:

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.

Description of key information

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.

Key value for chemical safety assessment

EC50 for freshwater algae:

110.6 mg/L

Additional information

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 chemical4-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.