2-methylaminoethanol

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:

Test period: 05 Oct 1993 to 08 Oct 1993

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study with analytical monitoring

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

- Name of test material (as cited in study report): Monomethylethanolamine
- Physical state: fluid
- Stability under test conditions: stable, not stable against acid solutions

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 100, 12,5 and 0.78 mg/L, untreated control and stock solution (200 mg/L) after 0 h (unin) and 72 h
- Sampling method: initial concentration (0 h, uninoculated replicate); final concentration (72 h, uninoculated and inoculated sample after removal of algal cells through centrifugation)

Vehicle:

no

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: Green algae
- Strain: Scenedesmus subspicatus CHODAT SAG 86.81
- Source (laboratory, culture collection): The used test strain of is purchased on regular times from the SAG (Sammlung Algenkulturen in Göttingen (Collection of algal culture in Göttingen, Germany) and kept in a liquid culture at the Laboratory of Ecology from BASF AG in Ludwigshafen, Germany.
- Age of inoculum (at test initiation): 72 h
- Method of cultivation: Stock cultures and precultures were kept in 250 mL erlenmeyers with 100 mL medium with an inoculation density of 10000 cells/mL. Stock cultures are weekly transferred, pre-cultures are incubated for 72h before use.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

23 ± 2° C

pH:

uninoculated samples, 0 h: 7.96 - 9.89
uninoculated samples, 72 h: 8.20 - 8.62
inoculated samples, 72 h: 8.55 - 9.65

Nominal and measured concentrations:

Nominal: 100, 50, 25, 12.5, 6.25, 3.13, 1.25, 0.78, 0.39 mg/L
Analytical recovery rates after 72 h: 88.8 - 103.0% in uninoculated samples, 88.8 - 108.0% in inoculated samples

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: 250 ml Erlenmeyer, 100 mL
- Initial cells density: 10000 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Intervals of water quality measurement: uninoculated 0, 72 h; inoculated 72 h

OTHER TEST CONDITIONS
- Photoperiod: permanent illumination, universal white light, L 25 (Osram)
- Light intensity and quality: 120 µE/(m²s)

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: counting chamber (Neubauer improved) at the timepoint, t=72h value.0 h-value is obtained from the inoculum
- Determination of fluorescence: At timepoints t=0, 24, 48, 72h, fluorescence was measured in a EOS filter fluorometer FL2. The in vivo chlorophyl-a fluorescence at 685 nm was determined as measure for biomass (pulsed excitation with light flashes having wavelengths of 435 nm)

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Justification for using less concentrations than requested by guideline: not applicable
- Range finding study: no data

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

28.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

(analytically verified)

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

10.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

(analytically verified)

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC90

Effect conc.:

38.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

(analytically verified)

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

5.97 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

(analytically verified)

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

18.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

(analytically verified)

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

EC90

Effect conc.:

39.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

(analytically verified)

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

3.13 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

(analytically verified)

Basis for effect:

other: fluorescence

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

6.25 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

(analytically verified)

Basis for effect:

other: fluorescence

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): no
- Any stimulation of growth found in any treatment: no
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no
- Effect concentrations exceeding solubility of substance in test medium: no

Reported statistics and error estimates:

- The EC values are calculated from the concentration-response relationship.
- The NOEC is determined by comparing the means of the fluorescence measurement of the various concentration levels with the control. The Duncan multiple range test is carried out at a 95% significance level .

Cell density (parameter fluorescence), mean of fluorometer units

Test item concentration (nominal; mg/L)	Exposure duration (h)				% of control (72 h)
	0	24	48	72
Control	71	231	1132	3601	100.0
100	64	22	3	6	0.2
50	63	59	38	26	0.7
25	63	176	697	800	22.2
12.5	64	202	1060	1862	51.7
6.25	64	211	1056	3141	87.2
3.13	65	204	1070	3402	94.5
1.56	69	209	1094	3630	100.8
0.78	63	207	1063	3387	94.1
0.39	67	204	1075	3610	100.2

  

Inhibition of cell growth and growth rate in comparison to the control after 72 hours 

Test item concentration (nominal; mg/L)	Biomass		Growth rate
	Absolute	Inhibition (%)	Absolute	Inhibition (%)
control	2915	-----	0.055	-----
100	-196	106.7	-0.033	160.3
50	-111	103.8	-0.012	122.5
25	1053	63.9	0.035	35.3
12.5	1969	32.5	0.047	14.2
6.25	2614	10.3	0.054	0.8
3.13	2748	5.7	0.055	-0.8
1.56	2877	1.3	0.055	-0.9
0.78	2743	5.9	0.055	-1.5
0.39	2850	2.2	0.055	-1.5

  

pH values at times t = 0 h and t= 72 h

Test item concentration (nominal; mg/L)	pH values
	0 h	72 h
	Uninoculated	Uninoculated	Inoculated
control	7.96	8.21	9.49
100	9.89	8.62	8.55
50	9.60	8.40	8.57
25	9.15	8.34	8.78
12.5	8.86	8.33	9.28
6.25	8.55	8.31	9.59
3.13	8.25	8.30	9.65
1.56	8.10	8.29	9.51
0.78	8.02	8.26	9.46
0.39	7.98	8.20	9.47

 After neutralisation no appreciable reduction on harmful effects can be observed.

Summary of the concentration control analysis (detection limit = 1 mg/L)

Time	Control	Recovery (%)
		Test item solutions	Stock solution
0 h, uninoculated	< 1 mg/L	93.6 – 103.0	103.5
72 h, uninoculated	< 1 mg/L	88.8 – 103.0	105.5
72 h, inoculated	< 1mg/L	88.8 – 108.0	-

Validity criteria fulfilled:

yes

Conclusions:

EC50 = 18.4 mg/L (effect: biomass)

Executive summary:

In a GLP, 72-hour static test with the green alga Scenedesmus subspicatus according to EU method C.3, the algae toxicity of 2-methylaminoethanol was studied. Statistical evaluation of the endpoint growth rate revealed an EC50 (72h) of 28.1 mg/L, the NOEC was found to be 3.13 mg/L and the LOEC was found to be 6.25 mg/L, related to the analytically verified concentrations (BASF 1993). Furthermore, an EC10 value (72 h; growth inhibition) of 10.1 mg/L is reported.

Description of key information

N-Methylaminoethanol is regarded to be acutely harmful to algae (BASF AG, 1994). 

Key value for chemical safety assessment

EC50 for freshwater algae:

18.4 mg/L

EC50 for marine water algae:

70 mg/L

EC10 or NOEC for freshwater algae:

3.13 mg/L

Additional information

Scenedesmus subspicatus was used as test organism in a static freshwater toxicity test (BASF AG, 1994). The test was performed according to EU Method C.3 with a time duration of 72 hours. After this exposure time an EC50 of 28.1 mg/L, and an EC10 of 10.1 mg/L based on growth rate as well as an EC50 value of 18.4 mg/L, based on biomass was found. Regarding biomass, a NOEC of 3.13 mg/L, a 72 h (ErC10 = 5.97 mg/L, and a LOEC of 6.25 mg/L were reported (biomass; measured; pH 7.98 - 9.65). Concerning these results, N-Methylethanolamine can be regarded to be acutely harmful to algae.

In a screening study with marine phytoplankton species Skeletonema costatum according to ISO guideline 10253 (1999) an EC50 (72 h) value of 70 mg/L (growth rate) was calculated for MMEA.