1-methylpiperidine-2-ethanol

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2018-08-07 - 2018-08-13 (experimental phase)

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

under GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

OECD Guideline for the Testing of Chemicals No. 201, adopted 23. Mar. 2006, Annex 5 corrected: 28 July 2011 “Freshwater Alga and Cyanobacteria, Growth Inhibition Test”

Deviations:

yes

Remarks:

but not affecting the validity of the study

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Version / remarks:

Regulation (EU) No. 2016/266 amending Regulation (EC) No. 440/2008, Annex IV, Method C.3: “FRESHWATER ALGAE AND CYANOBACTERIA, GROWTH INHIBI-TION TEST,” adopted 07. December 2015

Deviations:

yes

Remarks:

but not affecting the validity of the study

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

1-methylpiperidine-2-ethanol

EC Number:

208-554-7

EC Name:

1-methylpiperidine-2-ethanol

Cas Number:

533-15-3

Molecular formula:

C8H17NO

IUPAC Name:

2-(1-methylpiperidin-2-yl)ethanol

Test material form:

liquid

Specific details on test material used for the study:

The test item was stored in the test facility in a closed vessel dark and dry at 20 ± 5 °C.

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 0, 4.6, 10, 22, 46, 100 mg/l
- Sampling method: All samples were diluted in daphnia test medium so that they lay into the range of the cali-bration. All used dilutions factors are presented in the following table.

Treatment Dilution factor
4.6 mg/L 40
10 mg/L 100
22 mg/L 200
46 mg/L 400
100 mg/L 800

- Sample storage conditions before analysis: no

Test solutions

Vehicle:

no

Remarks:

algal medium was used

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
For elimination of the algal cells before analytical determination, samples were centrifuged.
Preparation
A stock solution containing 100.2 mg/L test item in algal medium (demineralised water enriched with minerals but without algae) was prepared. Lower test concentrations were prepared by dilution of the stock solution in algal medium.

Nominal concentration in mg/L Real load in mg/L
4.6 4.6
10 10.0
22 22.0
46 46.1
100 100.2

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: Unicellular freshwater green alga
- Strain: Desmodesmus subspicatus, SAG Strain Number 86.81
- Source (laboratory, culture collection): The culture of Desmodesmus subspicatus was obtained in January 2016 by MBM Sciencebridge GmbH (Institut für Pflanzenphysiologie of Universität Göttingen).
- Method of cultivation: The algae are kept as stock culture on solid agar at 2 - 8 °C. From the stock culture, a permanent culture was prepared. From an aliquot of the permanent culture, the pre-culture was prepared.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Post exposure observation period:

none

Test conditions

Test temperature:

16.0 – 26.7 °C

Nominal and measured concentrations:

4.6 / 10 / 22 / 46 / 100 mg/L nominal concentration

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): open / closed
- Material, size, headspace, fill volume: glass flasks, total volume 65 mL, 45 ±1 mL fill volume
- Initial cells density: 2340 / ml
- Control end cells density: 333987 / ml
- No. of vessels per concentration (replicates):
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: no
- Photoperiod: continuous
- Light intensity and quality: 5000 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: electronic particle counter

TEST CONCENTRATIONS
Treatments tested: 4.6 / 10 / 22 / 46 / 100 mg/L nominal concentration
- Range finding study / Test concentrations / Results used to determine the conditions for the definitive study: The concentrations to be tested were based on a non-GLP pre-test. In this pre-test, 100 % inhibition occurred at 100 mg/L. No inhibition occurred at 1 mg/L.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate K2Cr2O7 (CAS No. 7778-50-9) was used as positive control in a separate reference test.

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

< 4.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

< 4.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks:

yield

Effect concentrations 3

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

<= 4.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 4

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

<= 4.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks:

yield

Effect concentrations 5

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

12.78 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% confidence interval: 9.95 – 16.40 mg/L

Effect concentrations 6

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

2.74 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks:

yield

Remarks on result:

other: 95% confidence interval: 2.44 – 3.07 mg/L

Remarks:

extrapolated

Effect concentrations 7

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

47.19 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% confidence interval: 35.12 – 62.88 mg/L

Effect concentrations 8

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

12.04 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks:

yield

Remarks on result:

other: 95% confidence interval: 10.52 – 13.73 mg/L

Details on results:

- Exponential growth in the control (for algal test): yes. During the test exponential growth in the blank controls was given.
- Observation of abnormalities (for algal test): none
- 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: none

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- EC50:
Parameter Value 95% confidence interval
72h ErC50 0.90 mg/L 0.77 – 1.1 mg/L
72h EyC50 0.42 mg/L 0.35 - 0.51 mg/L

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The study was conducted under GLP according to OECD guideline 201 and EU method C.3 on the registered substance itself. The method is to be considered scientifically reasonable with no deficiencies in documentation or deviations from the guidelines, the validity criteria were met. Hence, the results can be considered as reliable to assess the toxicity of MPA towards algae.
Significant inhibition of algal growth was observed at all tested concentrations ranging from 4.6 to 100 mg/L. The EC50 (growth rate) was determined to be 47.19 mg/l. Hence, MPA does not need to be classified as acutely hazardous to the environment according to Regulation 1272/2008 and amendments, but as it is not readily biodegradable, it has to be classified as Aquatic Chronic Cat. 3.

Executive summary:

The study was conducted under GLP according to OECD guideline 201 and EU method C.3 on the registered substance itself.

One valid experiment was performed.

The study was performed using 5 concentrations ranging from 4.6 to 100 mg/L. Incubation time (test system Desmodesmus subspicatus) was 72 hours. The cell concentration of each replicate was determined by measuring the cell numbers every 24 hours with an electronic particle counter. Growth rate µ and the yield were determined from the cell number at the respective observation times.

Significant inhibition of algal growth was observed at all tested concentrations.

At the start and at the end of the test, the content of the test item in the test solutions was determined using LC-MS-MS.

The measured concentrations lay between 103 % and 111 % of the nominal concentrations at the beginning of the test and between 99 % and 106 % of the nominal concentrations at the end of the test. Therefore the biological results were based on the nominal concentration.

Due to the significant inhibitionat the lowest concentrated treatment, NOEC and LOEC can only be specified as a range.

The 72h-EC50 values of potassium dichromate (K2Cr2O7, CAS No. 7778-50-9) were determined in a separate reference test. The values lay within the range of the laboratory (growth rate 0.73 - 1.10 mg/L, yield 0.21 – 0.66 mg/L).

The following results for the test item 2-(1-methylpiperidin-2-yl) ethanol, (MPA) were determined:

 

Table Results of the test item

Endpoint	NOEC	LOEC	EC10	EC50
Growth Rate	< 4.60 mg/L	≤ 4.60 mg/L	12.78 mg/L	47.19 mg/L
Yield	< 4.60 mg/L	≤ 4.60 mg/L	2.74 mg/L (extrapolated)	12.04 mg/L

 

MPA has to be classified as Aquatic Chronic Cat. 3.