Ethyldimethylamine

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study according to national standards without analytical concentration verification

Qualifier:

according to guideline

Guideline:

other: German industrial standard test guideline DIN 38412, Part 9

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: green algae, (Scenedesmus subspicatus)
- Strain: SAG 86.81
ACCLIMATION
- Culturing media and conditions: same as test
Erlenmeyer flasks (nominal volume 250 ml) plugged with gas permeable siliconsponge caps
Temperature: 20 °C
Culturing volume: 100 ml

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

20 °C

pH:

8.1 -9.4

Nominal and measured concentrations:

Nominal concentrations: 0.029, 0.059, 0.117, 0.234, 0.469, 0.938, 1.875, 3.75, 7.5, 15, 30 mg/L. Aditionally a control was tested in parallel.

Details on test conditions:

TEST SYSTEM
- Test vessel: 10 mL test volume, test vessels not further specified
- Initial cells density: Initial count of algae cells/ml: 10000
- No. of vessels per concentration (replicates): 6; blank per concentration: 1
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes; OECD Medium
Temperature: 20 °C
Culturing volume: 100 ml


TEST MEDIUM / WATER PARAMETERS
Test substance preparation: none
- Culture medium different from test medium: no
- stock solution of test substance: 60 mg/L (pH: 10.5, conductivity: 54 µSiemens/cm); stock solution was diluted in test medium to reach the final test concentrations

OTHER TEST CONDITIONS
- pH: 8.5 ±0.5
- Light intensity and quality: 230/60 µE above /under test vessel, respectively

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

24.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% CL: 21.9 to 27.3 mg/L; recalculated value

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

11.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% CL: 9.33 to 13.4 mg/L; recalculated value

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

17 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: 95% CL: 8.45 to 96.4 mg/L; recalculated value

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

4.08 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield

Remarks on result:

other: 95% CL: 1.08 to 6.83 mg/L; recalculated value

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

15.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield

Remarks on result:

other: 95% CL: 9.85 to 30.5 mg/L; recalculated value

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

2.52 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: 95% CL: 0.111 to 5.54 mg/L; recalculated value

Reported statistics and error estimates:

The test was re-evaluated using ToxRatPro Version 2.09 using the measured fluorescence data which were equated with cell numbers.

The following nominal effect concentrations related to yield (EyC), growth rate (ErC), and biomass integral (EbC) were recalculated according to OECD TG 201 (adopted 23 Mar 2006) using the fluorescence values for inhibition of biomass from the original report. Since no calibration curve data were available, fluorescence data were equated with cell numbers:

Yield (mg/L)
	72 h	96 h
EyC10	4.1	1.7
EyC20	6.4	2.9
EyC50	15.4	7.9
Growth rate (mg/L)
	72 h	96 h
ErC10	11.6	6.1
ErC20	14.9	9.6
ErC50	24.2	23.2
Biomass integral (mg/L)
	72 h	96 h
EbC10	2.5	3.7
EbC20	4.9	5.7
EbC50	17.0	12.8
Original effect values as given in the report (nominal concentrations in mg/L)
EC20	0.82 - 9.2	0.77 - 3.0
EC50	19.6	7.6
EC90	> 30	29.6

Cell growth inhibition

Treatment [mg/L]	Growth rate inhibition [%]	Biomass decrease [%]	Yield Decrease [%]
Control	0	0	0.0
0.029	4.2	15.9	12.7
0.059	-1.0	5.4	4.2
0.117	1.8	7.9	6.9
0.234	0.2	6.9	3.4
0.469	2.5	11.2	10.0
0.938	9.2	21.9	25.1
1.875	-0.2	4.8	-0.8
3.750	0	7.7	3.7
7.500	4.0	14.5	16.7
15.000	16.1	29.3	37.1
30.000	66.2	90.7	90.2

pH values

Concentration [mg/L]	uninoculated		inoculated
	0 h	96 h	96 h
Control	8.5	8.3	9.0
0.029	8.6	8.2	9.0
0.059	8.6	8.1	9.1
0.234	8.6	8.1	9.1
0.469	8.6	8.1	9.0
0.938	8.6	8.1	9.0
1.875	8.6	8.1	9.0
3.75	8.7	8.1	8.8
7.5	8.8	8.1	8.5
15	9.1	8.1	8.4
30	9.4	8.1	8.3

Validity criteria fulfilled:

not applicable

Executive summary:

Acute toxicity to algae has been investigated according to German industrial standard test guideline DIN 38412, Part 9.

Algae were exposed for 96 hours to an aqueous solution of ethyldimethylamine at nominal concentrations of 0.029, 0.059, 0.117, 0.234, 0.469, 0.938, 1.875, 3.75, 7.5, 15, 30 mg/L.

ErC 50 - 72h has been estimated based on results obtained and is of 24.2 mg/L and ErC10 of 11.6 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:

24.2 mg/L

EC10 or NOEC for freshwater algae:

11.6 mg/L

Additional information

Ehyldimethylamine toxicity to green algae has been investigated by BASF in 1988. The methodology followed is the DIN 38412, Part 9. with exposure duration exceeding 72 h (96h). In this context, the extrapolated 72 h ErC50 determined is of 24.2 mg/L and a 72 h ErC10 of 11.6 mg/L.