2-methylaminoethanol

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1993-05-04 - 1993-05-06

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.2 (Acute Toxicity for Daphnia)

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: control, 1.56, 12, and 100 mg/L at test start (0 h) and at test end (48 h)
- Sample storage conditions before analysis: refrigerator

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Stock solution concentration 100 mg/L, by dilution of this stock solution with test medium the nominal concentrations were prepared.
- Eluate: no
- Differential loading: no

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Source: Institut National de Recherche Chimique Appliquée, France, in 1978. In-house culture
- Age at study initiation (mean and range, SD): 2-24 h
- Feeding during test: no

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

2.2 - 3.2 mM

Test temperature:

0 h: 21.8 °C;
24 h: 20.9 °C;
48 h: 21.0 °C

pH:

8.0 - 9.9

Dissolved oxygen:

8.3 - 8.6 mg/L

Nominal and measured concentrations:

Nominal (measured) [mg/L]: 100 (100.8), 50, 25, 12.5 (12.5), 6.25, 3.13, 1.56, 0.78

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: glass, tubes with flat bottom (nominal volume 20 mL), 10 mL
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Water composition: synthetic medium M4 was used on the basis of an ultrapure, deionized water (conductivity <0.05 µS/cm). The synthetic M4-medium was aerated unil saturated with oxygen; it was stored for at least 24 h for stabilization.
- Alkalinity up to pH 4.3: 0.87 mM
- Ca/Mg ratio: 4:1
- Conductivity: 601 µS/cm
- Total hardness: 2.42

OTHER TEST CONDITIONS
- Photoperiod: Artificial light, day:night rythm 16:8 hours
- Light intensity: 5 - 6 µE/(m²s)


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : swimming ability (observation intervals: 3; 6; 24; 48 hours)


TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

EC0

Effect conc.:

25 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

(analytically verified)

Basis for effect:

mortality

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

33 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

(analytically verified)

Basis for effect:

mortality

Remarks on result:

other: 95% CL: 30.0 - 36.2 mg/L

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

50 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

(analytically verified)

Basis for effect:

mortality

Details on results:

pH-effect : The neutralized samples of 100 mg/L pH 7 .0 (pH 9 .9), 50 mg/L pH 7 .1 (pH 9 .6) and 10 mg/L pH 7 .4 (pH 8 .7) showed compared with the not neutralized samples the same effect (results of a screening test).
- Mortality of control: 0%
- Effect concentrations exceeding solubility of substance in test medium: no

Reported statistics and error estimates:

Procedures to determine EC-values after 48 h: - EC50: moving average-method

Immobilisation: Total number of mobile Daphnids after exposure (48 h) to various test concentrations

Test item conc.  (mg/L)	Mobile Daphnids				Immobilisation (%)
	3 h	6 h	24 h	48 h	3 h	6 h	24 h	48 h
control	20	20	20	20	0	0	0	0
100	20	19	0	0	0	5	100	100
50	20	20	19	0	0	0	5	100
25	20	20	20	18	0	0	0	10
12.5	20	20	20	20	0	0	0	0
6.25	20	20	20	20	0	0	0	0
3.13	20	20	20	20	0	0	0	0
1.56	20	20	20	20	0	0	0	0
0.78	20	20	20	20	0	0	0	0

Neutralised test samples showed no decrease in toxic effects.

pH and oxygen values (measured in replicate 1)

Test item concentration (mg/L)	pH after		Dissolved oxygen after
	0 h	48 h	0 h	48 h
control	8.0	8.0	8.3	8.4
100	9.9	8.5	8.5	8.3
50	9.6	0.3	8.4	8.4
25	9.2	8.2	8.4	8.5
12.5	8.8	8.1	8.4	8.6
6.25	8.5	8.1	8.4	8.5
3.13	8.3	8.1	8.4	8.4
1.56	8.1	8.1	8.3	8.4
0.78	8.1	8.0	8.4	8.4

Supporting analytical chemistry

	Measured concentration (mg/L)			Recovery (%)
Test concentration (nominal, mg/L)	0 h	48 h		0 h	48 h
Stocked with daphnids	no	no	yes	no	no	yes
100	100.8	103.6	102.6	100.8%	103.6%	102.6%
12.5	12.5	12.6	12.8	100.0%	100.8%	102.4%
1.56	1 (1.3, 1.3)*	1 (1.3, 1.3)*	1 (1.3, 1.4)*	83.3%	83.3%	89.7%
control	<1	<1	<1	-	-	-

*: The concentrations found for these samples are very close to the limit of determination. Therefore, the accuracy of these data is less than the accuracy of the higher concentration levels.

Validity criteria fulfilled:

yes

Conclusions:

EC50 = 33 mg/L

Executive summary:

As key study concerning acute toxicity to freshwater invertebrates a GLP-test performed by BASF (1993) according to EU methoc C.2 was identified, using Daphnia magna as test species. In the static test an EC50 of 33 mg/L after 48 hours of exposure was calculated related to the analytically measured concentrations

Description of key information

The key value for chemical safety assessment is taken from an experimental result by BASF AG (1993).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

33 mg/L

Additional information

Concerning acute toxicity to freshwater invertebrates a GLP-test according to EU method C.2 is available (BASF AG, 1993). Using Daphnia magna as test species in this static test, an EC50 of 33 mg/L after 48 hours of exposure was determined. The test concentrations (nominal and not ph adjusted: 0, 0.78, 1.56, 3.13, 6.25, 12.5, 25, 50 and 100 mg/L) were analytically verified. As the recovery was between 90 % and 103 % the effect value was based on nominal concentrations.

The 48-hour EC₅₀ was - as mentionned above - 33 mg/L (measured; pH 8.0 – 9.9; 95% CI 30.0-36.2 mg/L). In this study, the pH values of up to pH 9.9 were observed after 3 h, exceeding the tolerable pH-range of pH 6.0 - pH 9.0. Therefore, the observed adverse effects may be partly caused by a pH-shift to more alkyline pH-values at higher test substance concentrations.