Sodium N-methyltaurinate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

OECD Guideline for Testing of Chemicals No. 201 "Alga, Growth Inhibition Test" adopted June 7, 1984

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Test substance: Metaupon, OMT-Paste Konz.
CAS-Number: 91673-22-2
Supplier: Leuna-Werke AG
Batch Number: 090491
Analysis Ref.: TGL 35682
Purity: techn. approximately 51 %

Details on test solutions:

The stock solution was prepared once before the beginning of the test. The amount of test material used was 500.2 mg. The test material was dissolved in 1 L twice glass distilled water and stirred for 20 min. The nominal concentration of the stock solution was 500.2 mg/L. pH-value: 8.9. Storage conditions: Temperature: room temperature, Duration: approx. 30 min in light.

The nominal concentrations to which the test organisms were exposed were 10, 25, 60, 150 and 360 mg/L.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

Chodat, SAG 86.81, green alga
Supplier: Institute of plant physiology, University of Goettingen, Goettingen, Germany.
Solid and liquid stock cultures of S. subspicatus have been cultured at Battelle Europe since August 1987.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

Temperature in the test solutions during the period of the test: 22.9 / 23 °C min/max

pH:

pH value during the period of the test: 7.9 / 8.4 min/max

Details on test conditions:

Exposure conditions
- Age of the pre-culture: 4 d
- Number of cells per mL in the pre-culture before inoculating the test solutions: 4.1E5
- Volume of pre-culture containing 1E6 cells: 2.439 mL
- pH-value of the concentrated algal medium II: 8.3
- Test vessels: 300 mL Erlenmeyer flasks containing 100 mL test solution covered with a cotton plug
- Number of cells per mL test solution at the beginning of the test: 1E4
- Number of replicates per test substance concentration: 4
- Number of replicates in the control: 4
- Light: light/dark (24/0 h) OSRAM L36W/25 (universal white)
- Quantum flux density: 120 +/- 10 µE/s/m² (400 - 700 nm)
- Shaker: 80 +/- 1 oscillations/min
- Temperature in the test room (average value): 23 +/- 1 °C

Reference substance (positive control):

yes

Remarks:

Reference substance: Potassium dichromate (K2Cr2O7)

Duration:

72 h

Dose descriptor:

EC50

Remarks:

EbC50

Effect conc.:

51 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

96 h

Dose descriptor:

EC50

Remarks:

EbC50

Effect conc.:

38 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

EC50

Remarks:

ErC50

Effect conc.:

156.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

96 h

Dose descriptor:

EC50

Remarks:

ErC50

Effect conc.:

114.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Duration:

72 h

Dose descriptor:

EC50

Remarks:

EbC50

Effect conc.:

34.7 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: Based on actual (measured) concentrations at the end of the test (on average 68% of nominal)

Duration:

96 h

Dose descriptor:

EC50

Remarks:

EbC50

Effect conc.:

25.8 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: Based on actual (measured) concentrations at the end of the test (on average 68% of nominal)

Duration:

72 h

Dose descriptor:

EC50

Remarks:

ErC50

Effect conc.:

106.4 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: Based on actual (measured) concentrations at the end of the test (on average 68% of nominal)

Duration:

96 h

Dose descriptor:

EC50

Remarks:

ErC50

Effect conc.:

77.7 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: Based on actual (measured) concentrations at the end of the test (on average 68% of nominal)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

6.8 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Remarks on result:

other: Based on actual (measured) concentrations at the end of the test (on average 68% of nominal)

Details on results:

The analytically determined actual concentrations of the test material at the beginning of the study were found to be within the range of 105 % and 117 % with an average of 111.7 %.
The analytically determined stability of the test material after 48 hours of exposure was found to be within the range of 36 % and 95 % of the nominal values with an average of 68 %.
It is thought that the low recoveries for the test substance after an exposure period of 96 hours was caused by biodegradation of the test substance.

Based on nominal concentrations the study resulted in the following values:
NOEC: 10.0 mg/L; EbC50 after 72 hours: 51.0 mg/L; after 96 hours: 38.0 mg/L; ErC50 after 72 hours: 156.4 mg/L; after 96 hours: 114.2 mg/L.
Based on actual (measured) concentrations at the end of the test (on average 68% of nominal) the study resulted in the following values:
NOEC: 6.8 mg/L; EbC50 after 72 hours: 34.7 mg/L; after 96 hours: 25.8 mg/L; ErC50 after 72 hours: 106.4 mg/L; after 96 hours: 77.7 mg/L.

Results with reference substance (positive control):

Control of the Test System:
Reference substance: Potassium dichromate (K2Cr2O7);
EbC10 (0-96 h): 0.25 mg/L ErC10 (24-96 h): 2.11 mg/L
EbC50 (0-96 h): 1.18 mg/L ErC50 (24-96 h): 3.22 mg/L
Performed in October 1990
EC10 values for potassium dichromate obtained from different laboratories range between 0.9 mg/L and 1.9 mg/L (RUDOLPH and BOJE, 1986).

Validity criteria fulfilled:

yes

Conclusions:

According to OECD guideline 201 the ErC50 and NOEC of sodium N-methyl oleoyl taurinate, derivatives for green algae were determined based on the measured concentration (on average 68 % nominal). The study results in the following values: ErC50 after 72 hours: 106.4 mg/L; after 96 hours: 77.7 mg/L and NOEC: 6.8 mg/L.

Executive summary:

The guideline study on acute toxicity of the test substance sodium N-methyl oleoyl taurinate, derivatives to algae was carried out according to OECD 201 using the green alga Desmodesmus subspicatus. The study reports the following values based on the measured concentrations at the end of the study (on average 68 % nominal): ErC50 after 72 hours: 106.4 mg/L; after 96 hours: 77.7 mg/L; EbC50 after 72 hours: 34.7 mg/L; after 96 hours: 25.8 mg/L; NOEC: 6.8 mg/L.

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

(Q)SAR

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

Justification for type of information:

The estimation is based on EPI Suite, ECOSAR v1.11. Two models are available, the estimation from the class (Aliphatic Amines-acid) and the Baseline Toxicity (neutral organic structure analysis relationship).

Principles of method if other than guideline:

The estimation is based on ECOSAR v1.11. Two models are available, the estimation from the Class (Aliphatic Amines-acid) and the Baseline Toxicity (neutral organic structure analysis relationship)

GLP compliance:

not specified

Specific details on test material used for the study:

Calculation is based on the structure of N-methyltaurinate
- Name of test material (as cited in study report): Ethanesulfonic acid, 2- (methylamino)-, monosodium salt

Analytical monitoring:

not required

Vehicle:

not specified

Test organisms (species):

other: green algae

Test type:

other: estimation by calculation

Water media type:

not specified

Total exposure duration:

96 h

Remarks on exposure duration:

EC50

Duration:

96 h

Dose descriptor:

EC50

Remarks:

(Aliphatic Amines-acid)

Effect conc.:

75 538.547 mg/L

Nominal / measured:

not specified

Conc. based on:

not specified

Basis for effect:

other: estimation by calculation

Duration:

96 h

Dose descriptor:

EC50

Remarks:

(Neutral Organic SAR)

Effect conc.:

118 000 mg/L

Nominal / measured:

not specified

Conc. based on:

not specified

Basis for effect:

other: estimation by calculation

Dose descriptor:

other: ChV

Remarks:

(Aliphatic Amines-acid)

Effect conc.:

16 636.625 mg/L

Nominal / measured:

not specified

Conc. based on:

not specified

Basis for effect:

other: estimation by calculation

Remarks on result:

other: ChV (chronic value, QSAR)

Dose descriptor:

other: ChV

Remarks:

(Neutral Organic SAR)

Effect conc.:

11 328.276 mg/L

Nominal / measured:

not specified

Conc. based on:

not specified

Basis for effect:

other: estimation by calculation

Remarks on result:

other: ChV (chronic value, QSAR)

Details on results:

ChV = 10^([log (LOEC x NOEC)]/2)

Validity criteria fulfilled:

not applicable

Conclusions:

The aquatic toxicity for green algae of sodium N-methyltaurinate is calculated by ECOSAR. The lowest calculated EC50 is 75.54 g/L (class: Aliphatic Amines-acid). The lowest calculated chronic toxicity value is 11.33 g/L (Neutral organic SAR).

Executive summary:

The aquatic toxicity for green algae of sodium N-methyltaurinate is calculated by ECOSAR. The lowest calculated EC50 is 75.54 g/L (class: Aliphatic Amines-acid). The lowest calculated chronic toxicity value is 11.33 g/L (Neutral organic SAR). Nevertheless, the estimation by calculation only provides an approximation and cannot replace empirical studies. The EPA recommends that EPI Suite is a screening-level tool and should not be used if acceptable measured values are available.

Description of key information

The aquatic toxicity for green algae of sodium N-methyltaurinate is calculated by ECOSAR using the model Aliphatic Amines-acid. The lowest calculated EC50 (96 h) is 75.54 g/L. The lowest chronic toxicity value estimated by calculation (ChV) is 11.33 g/L. The acute toxicity on algae of the read-across substance sodium N-methyl oleoyl taurinate, derivatives was assessed in the guideline study according to OECD 201 using Desmodesmus subspicatus. The study reports the following values based on the measured concentrations at the end of the test (on average 68 % nominal): NOEC: 6.8 mg/L; ErC50, 72 h and 96 h: 106.4 mg/L and 77.7 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:

77.7 mg/L

EC10 or NOEC for freshwater algae:

6.8 mg/L

Additional information

The aquatic toxicity for green algae of sodium N-methyltaurinate is calculated by ECOSAR using the model Aliphatic Amines-acid. The lowest calculated EC50 (96 h) is 75.54 g/L. The lowest chronic toxicity value estimated by calculation (ChV) is 11.33 g/L.

The acute toxicity on algae of the read-across substance sodium N-methyl oleoyl taurinate, derivatives was assessed in the guideline study according to OECD 201 using Desmodesmus subspicatus. According to the study, the NOEC is 6.8 mg/L and the ErC50 (72 h and 96 h) is 106.4 mg/L and 77.7 mg/L, respectively.

The empirically determined toxicity of sodium N-methyl oleoyl taurinate, derivatives is lower than the estimated EC50 (96 h) of sodium N-methyltaurinate. The EPA recommends that EPI Suite is a screening-level tool and should not be used if acceptable measured values are available. Nevertheless, both the empirical and estimated values are rather high, so that the studies on the read-across substance support the results of the EPI Suite estimation. Therefore, we conclude that the aquatic toxicity data of sodium N-methyl oleoyl taurinate, derivatives provide a reasonable measure to estimate the toxicity of sodium N-methyltaurinate on green algae.