1-Octanamine, N,N-dimethyl-, N-oxide

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:

November 20th, 2007 - July 7th, 2008

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

- Analytical purity: 82.3%
- Purity test date: Not available
- Lot/batch No.: GN-8
- Expiration date of the lot/batch: Not available
- Appearance: Amber coloured, extremely viscous liquid
- Storage: In the dark at room temperature
- Additional information on test material used for the study: It was attempted to purify the substance to a purity of >80% by using an alternative synthetic route, as opposed to the usual commercial route of synthesis which results in a purity of the substance of approximately 40% in water. This alternative synthetic route generated the substance at 82.3% purity, however it also generated an impurity (methanol at 4.0%) which is not present in the commercial substance. Based on the classification and labelling of methanol, it is considered that this additional impurity would not have an influence on any of the endpoints discussed in this dossier other than the acute oral toxicity study. Therefore all studies (including the one covering this endpoint) contained in this dossier (other than the acute oral toxicity study) were conducted on the 82.3% pure substance containing the 4.0% methanol impurity. The acute oral toxicity study has been conducted on the commercially generated substance at a purity of approximately 40% in water.

Analytical monitoring:

yes

Details on sampling:

Water samples were taken from the control (replicates R1-R6 pooled) and each test group (replicates R1-R3 pooled) at 0 and 72 hours for quantitative analysis. Duplicates samples were taken and stored at approximately -20°C for further analysis if necessary.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: Dissolved directly in culture medium
- Evidence of undissolved material (e.g. precipitate, surface film, etc): No

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: Desmodesmus subspicatus
- Strain: CCAP 276/20
- Source : Culture Collection of Algae and Protozoa (CCAP), Dunstaffnage Marine Laboratory, Oban, Argyll, Scotland
- Age of inoculum (at test initiation):
- Method of cultivation: Master cultureS maintained in the laboratory under constant aeration and constant illumination at 21 ± 1°C

Test type:

static

Water media type:

freshwater

Total exposure duration:

72 h

Hardness:

Not reported

Test temperature:

24 ± 1°C

pH:

7.3-7.8

Dissolved oxygen:

Not reported

Nominal and measured concentrations:

Definitive test: control, 1, 3.2, 10, 32, 100 mg a.i./L (analytically confirmed nominal concentrations)

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass conical flask (250 mL)
- Type : Closed (vessels covered to reduce evaporation)
- Fill volume: 100 mL
- Aeration: No aeration
- Initial cells density: 4E3 cells/mL
- Mean cell density of control at 0 hours: 4.56E3 cells/mL
- Mean cell density of control at 72 hours: 4.22E5 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: No
- Detailed composition if non-standard medium was used:
**NaNO3 25.5mg/l
**MgCl2.6H2O 12.164mg/l
**CaCl2.2H2O 4.41mg/l
**MgSO4.7H2O 14.7mg/l
**K2HPO4 1.044mg/l
**NaHCO3 15.0mg/l
**H3BO3 0.1855mg/l
**MnCl2.4H2O 0.415mg/l
**ZnCl2 0.00327 mg/l
**FeCl3.6H2O 0.159 mg/l
**CoCl2.2H2O 0.000012mg/l
**Na2EDTA.2H2O 0.30 mg/l
**Na2SeO3.5H2O 0.30 mg/l
The culture medium was prepared using reverse osmosis purified deionised water and the pH adjusted to 7.5 ± 0.1 with 0.1N NaOH or HCL.

OTHER TEST CONDITIONS
- Sterile test conditions: Yes
- Photoperiod: Continuous illumination
- Light intensity and quality: 7000 lux, warm white lighting (380-730 nm)
- Temperature: 24 ±1 °C
- Agitation: Constant shaking by orbital shaker (150 rpm)

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: Cell density determined using a Coulter Multisizer Particle Counter.

TEST CONCENTRATIONS
- Range-finding test(s): Yes (one)
- Test concentrations (range-finding test): 0.1, 1.0, 10 and 100 mg a.i./L

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Remarks:

1-octanamine, N, N-dimethyl-, N-oxide

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

49 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Remarks:

1-octanamine, N, N-dimethyl-, N-oxide

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

20 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Remarks:

1-octanamine, N, N-dimethyl-, N-oxide

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

11 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Remarks:

1-octanamine, N, N-dimethyl-, N-oxide

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

27 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Remarks:

1-octanamine, N, N-dimethyl-, N-oxide

Basis for effect:

cell number

Remarks:

yield

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

23 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Remarks:

1-octanamine, N, N-dimethyl-, N-oxide

Basis for effect:

cell number

Remarks:

yield

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Remarks:

1-octanamine, N, N-dimethyl-, N-oxide

Details on results:

All test and control cultures were inspected microscopically at 72 hours. There were no abnormalities detected in any of the control or test culture at 72 hours.

At the start of the test all control and test cultures were observed to be clear colourless solutions. After the 72-hour test period all control, 1, 3.2 and 10 mg/L test cultures were observed to be pale green dispersions. The 32 mg/L test cultures were observed to be very pale green dispersions whilst the 100 mg/L test cultures were observed to be clear colourless solutions.

Results with reference substance (positive control):

The results from the positive control with potassium dichromate were within the normal range for this reference material. The 72-hour EC50 value calculated was 0.49 mg/L based on growth rate, 0.23 mg/L based on biomass, and 0.22 mg/L based on yield. The 72-hour NOEC value calculated was 0.125 mg/L based on growth rate, 0.0625 mg/L based on biomass, and 0.0625 mg/L based on yield.

Daily specific growth rates for controls

		Daily Specific Growth Rate
		Day 0 – 1	Day 1 - 2	Day 2 – 3
Control	R1 R2 R3 R4 R5 R6 Mean	0.058 0.067 0.059 0.068 0.061 0.061 0.062	0.062 0.055 0.059 0.062 0.072 0.064 0.062	0.076 0.082 0.067 0.061 0.063 0.065 0.069

 Inhibition of growth rate, yield and biomass

Nominal Concentration (mg/l notifiable substance)		Growth Rate (cells/ml/hour)		Yield (cells/ml)		Biomass Integral
		0-72h	% Inhibition	0-72h	% Inhibition*	0-72h	% Inhibition
Control	R1 R2 R3 R4 R5 R6 Mean SD	0.065 0.068 0.062 0.064 0.065 0.063 0.065 0.002	-	4.34E+05 5.33E+05 3.33E+05 3.89E+05 4.34E+05 3.80E+05 4.17E+05 6.85E+04	-	7.12E+06 8.48E+06 5.84E+06 7.14E+06 7.75E+06 6.73E+06 7.18E+06 8.95E+05	-
1.0	R1 R2 R3 Mean SD	0.062 0.069 0.062 0.064 0.004	5 [6] 5 1	3.37E+05 5.85E+05 3.32E+05 4.18E+05 1.45E+05	0	6.06E+06 8.73E+06 6.17E+06 6.98E+06 1.51E+06	16 [22] 14 3
3.2	R1 R2 R3 Mean SD	0.061 0.065 0.065 0.064 0.002	6 0 0 2	3.29E+05 4.33E+05 4.34E+05 3.99E+05 6.06E+04	4	5.74+06 6.91E+06 6.74E+06 6.47E+06 6.31E+06	20 4 6 10
10	R1 R2 R3 Mean SD	0.064 0.068 0.063 0.065 0.003	2 [5] 3 0	3.86E+05 5.31E+05 3.62E+05 4.26E+05 9.16E+04	[2]	6.32E+06 8.05E+06 5.68E+06 6.68E+06 1.23E+06	12 [12] 21 7
32	R1 R2 R3 Mean SD	0.037 0.037 0.037 0.037 0.000	43 43 43 43	5.42E+04 5.27E+04 5.14E+04 5.28E+04 1.41E+03	87	9.79E+05 9.63E+05 1.03E+06 9.92E+05 3.71E+04	86 87 86 86
100	R1 R2 R3 Mean SD	0.020 0.021 0.020 0.020 0.001	69 68 69 69	1.22E+04 1.35E+04 1.22E+04 1.26E+04 7.41E+02	97	2.49E+05 2.11E+05 1.90E+05 2.17E+05 3.02E+04	97 97 97 97

*In accordance with the OECD test guideline only the mean value for yield for each test concentration is calculated

R₁- R₆= Replicates 1-6

SD = Standard Deviation

Validity criteria fulfilled:

yes

Conclusions:

A 72-hour 50% effective concentration ErC50 of 49 mg a.i./L (1-octanamine, N, N-dimethyl-, N-oxide) and a 10% effective concentration ErC10 of 10 mg a.i./L were obtained for growth rate inhibition based on analytically confirmed nominal concentrations of the test material.

Executive summary:

The toxicity of the test material to freshwater green algae (Desmodesmus subspicatus) was determined in a GLP-compliant study performed in accordance with OED Guideline 201 and EU Method C.3.

A 72-hour 50% effective concentration ErC50 of 49 mg a.i./L (1-octanamine, N, N-dimethyl-, N-oxide) and a 10% effective concentration ErC10 of 10 mg a.i./L were obtained for growth rate inhibition based on analytically confirmed nominal concentrations of the test material.

Description of key information

The toxicity of the test material to freshwater green algae (Desmodesmus subspicatus) was determined in a GLP-compliant study performed in accordance with OED Guideline 201 and EU Method C.3.

A 72-hour 50% effective concentration ErC50 of 49 mg a.i./L (1-octanamine, N, N-dimethyl-, N-oxide) and a 10% effective concentration ErC10 of 10 mg a.i./L were obtained for growth rate inhibition based on analytically confirmed nominal concentrations of the test material.

Key value for chemical safety assessment

EC50 for freshwater algae:

49 mg/L

EC10 or NOEC for freshwater algae:

10 mg/L

Additional information

The toxicity of the test material to freshwater green algae (Desmodesmus subspicatus) was determined in a GLP-compliant study performed in accordance with standard methods, without deviations. The study is considered as reliable (Klimisch 1) and was selected as key study for the endpoint.