Butanone oxime

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The test parameters evaluated in this study comply with a specific test guideline (Dutch NEN 6504), are well documented, scientifically acceptable, but not performed according to GLPs.

Qualifier:

according to guideline

Guideline:

other: BASF in-house test DIN 38 412/9

GLP compliance:

no

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Test type:

static

Water media type:

freshwater

Total exposure duration:

72 h

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

ca. 55 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

ca. 83 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC90

Effect conc.:

ca. 120 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Conclusions:

For the freshwater alga Desmodesmus subspicatus, the 72-hour EC20, EC50 and EC90 (growth rate) are 55, 83 and 120 mg MEKO/L, respectively.

Reference 2

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:

other: The study was conducted according to generally vaiid procedures and according to GLP guidelines. All parameters described are closely related or comparable to guideline methods.

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: all
- Sampling method:test solutions taken from the middle layer of test vessels were mixed

Vehicle:

no

Details on test solutions:

Five nominal concentrations of 40.0, 16.0, 6.40, 2.5 6 or 1.02 mg MEKO/L . Solubilizer was not used. Concentrations of the test substance were kept close to the nominal concentrations throughout the 72-hour test (100 to 112%).

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method:
- Eluate:
- Differential loading:
- Controls:
- Chemical name of vehicle (organic solvent, emulsifier or dispersant):
- Concentration of vehicle in test medium (stock solution and final test solution(s) including control(s)):
- Evidence of undissolved material (e.g. precipitate, surface film, etc):

Test organisms (species):

Scenedesmus capricornutum

Details on test organisms:

TEST ORGANISM
- Common name: Selenastrum capricornutum
- Strain - ATCC 22662
- Source (laboratory, culture collection):originally from the American Type Culture Collection (12301 Parklawn
Drive Rockville, Maryland 20852-1776 U.S.A.), and has been cultured under sterile condition in this laboratory
- Age of inoculum (at test initiation): 3 days

ACCLIMATION
- Acclimation period: 3 days
- Culturing media and conditions - same as test

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Hardness:

not reported

Test temperature:

23.4

pH:

8.0 at time 0, 8.3 - 9.6 at 72 hours

Dissolved oxygen:

Not reported

Salinity:

Not applicable

Nominal and measured concentrations:

Measured concentrations within 80% of nominal concentrations

Details on test conditions:

TEST SYSTEM
- Test vessel:500 mL Erlenmeyer flask
- fill volume: 100 ml
- Type of flow-through (e.g. peristaltic or proportional diluter):
- Renewal rate of test solution (frequency/flow rate):
- Initial cells density: 1 x 104 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3

GROWTH MEDIUM
- Standard medium used: yes

OTHER TEST CONDITIONS
- Adjustment of pH:No
- Photoperiod: continuous
- Light intensity and quality:4,000 to 5,000 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: [counting chamber; electronic particle counter; fluorimeter; spectrophotometer; colorimeter]
- Chlorophyll measurement:
- Other:

TEST CONCENTRATIONS
- Spacing factor for test concentrations: geometric ratio 2.5
- Justification for using less concentrations than requested by guideline:
- Range finding study
- Test concentrations:40.0, 16.0, 6.40, 2.56 and 1.02 mgIL
- Results used to determine the conditions for the definitive study: 88.4% inhibition at 32 mg/l, 5.8% inhibition at 3.2 mg/l

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

ca. 11.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

ca. 2.56 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

ca. 6.09 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

ca. 1.02 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Details on results:

- Exponential growth in the control (for algal test): yes
- Other: swollen cells at concentrations of 16 mg/l and hgher
- Any stimulation of growth found in any treatment:- 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:

Validity criteria fulfilled:

yes

Remarks:

as noted in OECD guideline

Conclusions:

For the freshwater alga Scenedesmus capricornutum, the 24-48 hour EC50 and 24-72 hour EC50 (growth rate) are 11.6 and 11.8 mg MEKO/L, respectively. The 24-48 hour NOEC and the 24-72 hour NOEC (growth rate) are both 2.56 mg MEKO/L. The 72-hour EC50 (biomass) and the 72-hour NOEC (biomass) are 6.09 mg MEKO/L and 1.02 mg MEKO/L, respectively.

Description of key information

The 72-h NOErC of 2.56 mg/L and the 72-r ErC50 of 11.8 mg/L in Scenedesmus capricornutum will be used in the assessment.

Key value for chemical safety assessment

EC50 for freshwater algae:

11.8 mg/L

EC10 or NOEC for freshwater algae:

2.56 mg/L

Additional information

Two growth inhibition tests with aquatic algae are available for MEKO. The first one (Kurume Laboratory, 1998e) is a freshwater static GLP-compliant OECD Guideline 201 test with Scenedesmus capricornutum, performed with analytical monitoring. The 72-h NOEC is 2.56 mg/L based on growth rate and the 72-h ErC50 was 11.8 mg/L. The second study (BASF, 1988) is a non-GLP static test with Scenedesmus subspicatus (new name: Desmodesmus subspicatus), performed according to DIN 38 412/9. In this test a 72-h EC50 of 83 mg/L is reported based on growth rate. The most critical study of Kurume Laboratory (1998e) is regarded as the key study.