4-methylpentan-2-one oxime

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:

17 September to 11 October 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

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)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: SANCO/3029/99 rev.4 11/07/00: Residues: Guidance for generating and reporting methods of analysis in support of pre-registration data requirements for Annex II and Annex III of directive 91/414

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

4-methylpentan-2-one oxime

EC Number:

203-298-2

EC Name:

4-methylpentan-2-one oxime

Cas Number:

105-44-2

Molecular formula:

C6H13NO

IUPAC Name:

4-methylpentan-2-one oxime

Test material form:

liquid

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: 2017090814
- Expiration date of the lot/batch: September 30, 2019
- Purity test date: July 10, 2018

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: At 20 +- 5 °C, in the dark

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 6.25, 12.5, 25, 50, 100 mg/L

- Sampling method: The samples were taken from the biological phase of the study. Duplicate samples from the freshly prepared test media (containing algae) of all test concentrations and from the control were taken at the start of the test.For the determination of the stability of the test item under the test conditions and of the maintenance of the test item concentrations during the test period, duplicate samples from the test media of all test concentrations and the control (containing algae) were taken at the end of the test (after the 72 hours test period) by pouring together the contents of the test beakers of each treatment.
All samples were diluted by a factor of two with acetonitrile.
Additional samples of the control and of the dilution solvent were taken at each sampling without any sample treatment.

- Sample storage conditions before analysis: All samples were stored in a freezer (≤ - 20 °C), protected from light until analysis was performed.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The test medium of the highest test concentration of nominal 100 mg test item/L was prepared by dissolving 101.9 mg test item into 1019 mL test water by intense stirring for 10 minutes. Adequate volumes of this test medium were diluted with test water to prepare the test media of the other desired test concentrations. The test media were prepared just before introduction of the algae (= start of the test).
- Controls: yes

Test organisms

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Strain: 61.81 SAG
- Source (laboratory, culture collection): The algae were originally supplied by the „Sammlung von Algenkulturen, Albrecht-von-Haller-Institut für Pflanzen-wissenschaften, Universität Göttingen", 37073 Göttingen, Germany.
- Age of inoculum (at test initiation): The cells were taken from an exponentially growing pre-culture, which was set up 3 days prior to the test start under the same conditions as in the test.
- Method of cultivation: The algae were cultivated in the laboratories of ibacon under standardised conditions according to the test guidelines.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test conditions

Hardness:

0.24 mmol/L (= 24 mg/L) as CaCO3

Test temperature:

21.1 to 22.7 °C

pH:

7.9 to 8.1 at the start of the test
10.0 to 10.1 at the end of the test

Dissolved oxygen:

not indicated

Salinity:

not applicable

Conductivity:

not applicable

Nominal and measured concentrations:

Nominal concentrations: 6.25, 12.5, 25, 50, 100 mg test item/L

Mean measured concentration (t=0h) : 98.936 mg test item/L
Mean measured concentration (t=72h): 97.8135 mg test item/L

The concentrations of the test item were analysed in the duplicate test media samples from the highest test concentration and in the duplicate control samples, from both sampling times (0 and 72 hours). The other test concentrations were not measured, since they were below the NOEC determined in this test.

Details on test conditions:

TEST SYSTEM
- Test vessel: erlenmeyer flasks
- Material, size, headspace, fill volume: erlenmeyer flasks of 50 mL volume with 50 mL of test medium
- Aeration: The flasks were covered with air permeable glass dishes
- Initial cells density: a biomass of nominal 5000 algal cells per mL test medium
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
Analytical grade salts were added at the following nominal concentrations in deionised water:
Macro-nutrients: NaHCO3 50.0 mg/L
CaCl2 x 2 H2O 18.0 mg/L
NH4Cl 15.0 mg/L
MgSO4 x 7 H2O 15.0 mg/L
MgCl2 x 6 H2O 12.0 mg/L
KH2PO4 1.6 mg/L
Trace Elements: Na2EDTA x 2 H2O 100.0 µg/L
FeCl3 x 6 H2O 64.0 µg/L
MnCl2 x 4 H2O 415.0 µg/L
H3BO3 185.0 µg/L
Na2MoO4 x 2 H2O 7.0 µg/L
ZnCl2 3.0 µg/L
CoCl2 x 6 H2O 1.5 µg/L
CuCl2 x 2 H2O 0.01 µg/L

OTHER TEST CONDITIONS
- Adjustment of pH: The pH was adjusted with from 7.9 to 8.1 with 1 M NaOH after preparation
- Photoperiod: Continuous illumination
- Light intensity and quality: Mean light intensity: 5947 lux (range: 5100 to 6590 lux)

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: The cell density on each observation time was determined by spectrophotometric measurement.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Range finding study: Pre-experiments were performed to determine a suitable concentration range and to establish suitable methods to prepare the test solutions.
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 4

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 5

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): none indicated
- Unusual cell shape: no
- Colour differences: none indicated
- Flocculation: none indicated
- Adherence to test vessels: none indicated
- Aggregation of algal cells: none indicated

Results with reference substance (positive control):

- Results with reference substance valid? yes
- EC50: the EC50 for yield was 0.402 mg test item/L, the EC50 for growth rate was 0.963 mg test item/L and the EC50 for biomass was 0.414 mg test item/L

Reported statistics and error estimates:

Based on the calculated cell densities, the 72 hours ErC50 and the 72 hours EyC50 (see Definitions) could not be calculated by a statistical analysis due to the lack of effects and were therefore determined directly from the raw data.
For the determination of the 72 hours LOEC and the 72 hours NOEC, the calculated growth rates and yields at each test concentration were tested for significant differences compared to the control values by Dunnett´s t-test.
The software used to perform the statistical analysis was ToxRat Professional, Version 3.2.1, ToxRat(R) Solutions GmbH.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The influence of MIBKO on the growth of the freshwater green algae Pseudokirchneriella subcapitata was assessed in a 72-hour static concentration-response test according to OECD 201. No effects were seen up to a concentration of 100 mg/L.The results of the test can be considered reliable without restriction.