N,N-bis(2-hydroxyethyl)undec-10-enamide

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:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Vehicle:

no

Details on test solutions:

Stock solution: 100 mg test substance/L, freshly prepared with dilution water, agitation until the solution was visually clear,
Test concentrations: the stock solution and four dilution levels out of the stock solution were tested in a geometrical series: 1.00, 3.16, 10.0, 31.8, 100 mg/L. The dilution levels are based on the results of a preliminary range finding test (non-GLP),
Control: Six replicates (without test substance) were tested under the same test conditions as the test vessels.

Test organisms (species):

Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)

Details on test organisms:

Test organism: Pseudokirchneriella subcapitata HINDAK. SAG 61.81
Origin: Sammlung von Algenkulturen (SAG), Universitat Gottingen, Germany
Cultivation at test facility: fresh stocks are prepared every month on Z-Agar. Light intensity amounted to 2567 - 5130 lux for 24 hours per day.
Culture medium: Nutrient medium Z according to LOTTGE et a/. (1994)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Hardness:

0.24 mmol Ca+Mg/L

Test temperature:

22.0 - 23.0°C

pH:

7.83 - 8.83

Nominal and measured concentrations:

- Nominal: 1.00, 3.16, 10.0, 31.6, 100 mg/L
- Measured: The measured concentrations of the test substance at the start of the exposure (0 hours) were in the range of 102 to 114 % of the nominal values. The measured concentrations of the test substance at the end of the exposure (72 hours) were in the range of 103 to 117 % of the nominal value.

Details on test conditions:

Replicates: three replicates per concentration level and six for the control were tested
Test container: sterile Erlenmeyer flasks (vol. 250 mL) with cotton wool plugs
Test volume: 100 mL
Preculture: a four days old preculture, prepared in dilution water, was used as inoculum
Initial cell density, nominal: approximately 5 x 10+E03 – 10+E04 cells/mL
Current: 6839 cells/mL
Application: Application was carried out by adding appropriate volumes of the stock solution to the replicate test vessels
Incubation: the flasks were positioned randomly and repositioned daily
Temperature (target), nominal range: 21 - 24 °C, controlled at ± 2 °C
Agitation: test containers were placed on a rotary shaker and oscillated at approximately 70 rpm
Light intensity (target): Approximately 4440 to 8880 lux, corresponding to 60 to 120 pE*m-2*s-1
Light regime: 24 hours/day light
Light homogeneity (target): Within ± 15 % over incubation area

Biological Parameters:

Chlorophyll a-fluorescence
Cell density was measured daily via Chlorophyll a-fluorescence, excitation at 436 nm, emission at 685 nm. Dilution water was used as a background signal. No self-fluorescence was found in the preliminary range finding test at 100 mg/L.
Microscopic evaluation
Microscopic evaluation of the cells at the start and the end of exposure was carried out. The cells were checked for unusual cell shapes, colour differences, differences in chloroplast morphology, flocculation, adherence of algae to test containers and agglutination of algae cells.

Physico-chemical Properties:

The pH-value at the start of the exposure and at the end of the exposure were measured from pooled samples of each test substance concentration and the control after measurement of the cell density. The room temperature was measured continuously. Light intensity was measured prior to the start of exposure.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

ca. 45.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: (95 % CI: 41.6 - 50.3 mg/L)

Remarks:

equivalent to 41.22 mg a.i./L

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

ca. 8.35 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: (95% CI: 6.51 - 10.5 mg/L)

Remarks:

equivalent to 7.57 mg a.i./L

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

ca. 3.16 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: equivalent to 2.86 mg a.i./L

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

ca. 10.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Remarks on result:

other: (95% CI: 8.33 - 13.4 mg/L)

Remarks:

equivalent to 9.60 mg a.i./L

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

ca. 1.56 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Remarks on result:

other: (95% CI: <1.00 - 3.68 mg/L)

Remarks:

equivalent to 1.41 mg a.i./L

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

ca. 3.16 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Remarks on result:

other: equivalent to 2.86 mg a.i./L

Results with reference substance (positive control):

- Growth rate 72 h EC50: 0.559 mg/L (95 % CI: 0.538 - 0.581)
- Yield 72 h EC50: 0.320 mg/L (95 % CI: 2.242 - 0.341)

Reported statistics and error estimates:

All calculations were based on the fluorescence values of each replicate. The fluorescence values were related to cell density values fluorescence value according to a calibration curve.
The growth rate, the growth rate inhibition, the yield and the inhibition of yield after 72 hours were calculated from the cell density values.
EC10, EC20 and EC50 values with confidence intervals were calculated by sigmoidal dose-response.
NOEC, LOEC and statistical The NOEC and LOEC were determined by calculation of analyses statistically significant differences of growth rates and yield. As a standard, One Way Analysis of Variance (ANOVA) and DUNNETT'S test were used for NOEC/LOEC calculations.
When running a One Way Analysis of Variance, a Normality test and an Equal Variance test were done first. P-values for both Normality and Equal Variance tests are 0.05.

None.

Validity criteria fulfilled:

yes

Conclusions:

Under the study conditions, growth rate and yield data (nominal) were determined as follows, growth rate: 72 h NOEC: 3.16 mg/L (equivalent to 2.86 mg a.i./L), 72 h LOEC: 10.0 mg/L (equivalent to 9.06 mg a.i./L), 72 h EC50: 45.5 mg/L (equivalent to 41.22 mg a.i./L); biomass: 72 h NOEC: 3.16 mg/L (equivalent to 2.86 mg a.i./L), 72 h LOEC: 10.0 mg/L (equivalent to 9.06 mg a.i./L), 72 h EC50: 10.6 mg/L (equivalent to 9.60 mg a.i./L).

Executive summary:

A study was conducted to determine the toxicity of the test substance, C11-unsatd. DEA (90.6% active), to Pseudokirchneriella subcapitata according to OECD Guideline 201 and EU Method C.3, in compliance with GLP. The study was conducted under static conditions with an initial cell density of 6839 cells/mL. A stock solution of 100 mg/L was prepared with dilution water. Five concentrations were tested in a geometrical series with a dilution factor of 3.16 (nominal): 1.00, 3.16, 10.0, 31.6 and 100 mg/L. Three replicates were tested for each test group and six replicates for the control. Test substance concentrations were analytically verified by LC-MS/MS at the start and end of the exposure period. Measured concentrations at test start were in the range of 102 - 114% of nominal values. At test end, they were in the range of 103 - 117% of nominal value. Under the study conditions, growth rate and yield data (nominal) were determined as follows, growth rate: 72 h NOEC: 3.16 mg/L (equivalent to 2.86 mg a.i./L), 72 h LOEC: 10.0 mg/L (equivalent to 9.06 mg a.i./L), 72 h EC50: 45.5 mg/L (equivalent to 41.22 mg a.i./L); biomass: 72 h NOEC: 3.16 mg/L (equivalent to 2.86 mg a.i./L), 72 h LOEC: 10.0 mg/L (equivalent to 9.06 mg a.i./L), 72 h EC50: 10.6 mg/L (equivalent to 9.60 mg a.i./L) (Herrmann, 2017).

Key value for chemical safety assessment

EC50 for freshwater algae:

45.5 mg/L

EC10 or NOEC for freshwater algae:

3.16 mg/L

Additional information

A study was conducted to determine the toxicity of the test substance, C11-unsatd. DEA (90.6% active), to Pseudokirchneriella subcapitata according to OECD Guideline 201 and EU Method C.3, in compliance with GLP. The study was conducted under static conditions with an initial cell density of 6839 cells/mL. A stock solution of 100 mg/L was prepared with dilution water. Five concentrations were tested in a geometrical series with a dilution factor of 3.16 (nominal): 1.00, 3.16, 10.0, 31.6 and 100 mg/L. Three replicates were tested for each test group and six replicates for the control. Test substance concentrations were analytically verified by LC-MS/MS at the start and end of the exposure period. Measured concentrations at test start were in the range of 102 - 114% of nominal values. At test end, they were in the range of 103 - 117% of nominal value. Under the study conditions, growth rate and yield data (nominal) were determined as follows, growth rate: 72 h NOEC: 3.16 mg/L (equivalent to 2.86 mg a.i./L), 72 h LOEC: 10.0 mg/L (equivalent to 9.06 mg a.i./L), 72 h EC50: 45.5 mg/L (equivalent to 41.22 mg a.i./L); biomass: 72 h NOEC: 3.16 mg/L (equivalent to 2.86 mg a.i./L), 72 h LOEC: 10.0 mg/L (equivalent to 9.06 mg a.i./L), 72 h EC50: 10.6 mg/L (equivalent to 9.60 mg a.i./L) (Herrmann, 2017).