Isobutyrophenone

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline with analytical monitoring

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Isobutyrophenone

EC Number:

210-275-0

EC Name:

Isobutyrophenone

Cas Number:

611-70-1

Molecular formula:

C10H12O

IUPAC Name:

2-methyl-1-phenylpropan-1-one

Details on test material:

- Name of test material (as cited in study report): Isobutyrophenone (TK 40392)
- Physical state: Liquid / colorless, clear
- Analytical purity: 99.2 area-%
- Batch No.: 090727T102
- Storage condition of test material: the test substance was stored at ambient temperature

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: The test solutions were prepared separately for each test concentration. The stock solution vessels and test vessels were saturated with test solution for approx 1 day before the start of exposure. The test substance was homogenized by shaking the container before use. For each concentration, the test substance was weighed into a 1 L volumetric flask and filled to the mark with test medium. The solution was then be stirred for approximately 10 min at 20 ± 2 °C. The solutions were checked visually to ensure that the test substance is completely dissolved. All test solutions were visibly clear and colorless after preparation.

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: green alga
- Strain: SAG 86.81
- Source (laboratory, culture collection): Collection of algal cultures in University of Göttingen, Germany
- Age of inoculum (at test initiation): 3 days

CULTURE
- Inoculum culture cell density (3 days growth) : 50E+04 cells/mL (100 fold increase)
- Inoculum culture morphology: normal and healthy

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Test temperature:

22.4 – 22.6 °C

pH:

7.9 - 8.1

Nominal and measured concentrations:

Nominal test concentrations: control, 1.0, 3.2, 10, 32, 100 mg/L
Mean measured concentrations: -, -, -, 8.3, 21.4, 56.2 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Material, nominal volume, fill volume: Erlenmeyer flasks plugged with gas permeable silicone sponge caps, 250 mg/L, 100 mg/L
- Initial cells density: 0.5E+04 cells/ml
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: The test medium was prepared according to OECD Guideline for Testing of Chemicals, No. 201 Algal growth inhibition test
- Culture medium different from test medium: no
- Intervals of water quality measurement: pH in one uninoculated replicate and one inoculated replicate at study initiation and in all replicates at study end. Temperature was continuously measured during the whole test period in the climate chamber in a flask with deionized water

OTHER TEST CONDITIONS
- Photoperiod: permanent illumination
- Light intensity and quality: artificial light, type universal white (OSRAM L 25), average 5219 lux (within ± 15% variability) at a wave length of 400 - 700 nm

EFFECT PARAMETERS MEASURED:
- Determination of cell concentrations: two counts in a Neubauer haemocytometer
- Chlorophyll measurement: in vivo chlorophyll-a fluorescence (pulsed excitation with light flashes having a wavelength of 432 nm) after 0, 24, 48, 72 h
- Other: The inoculum culture was observed microscopically at the start of the test to verify normal and healthy cells. At test termination, a pooled sample from each test concentration was examined and any abnormal appearance of the algae noted.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: geometric series, ≤3.2
- Range finding study: yes
- Results used to determine the conditions for the definitive study: EfC50 > 29.9 mg/L (nominal) ; ErC50 > 30.3 mg/L (nominal)

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

22.8 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

33.8 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC90

Effect conc.:

50.1 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 4

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

21.4 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 5

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

7.88 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

other: yield

Effect concentrations 6

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

28.1 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

other: yield

Effect concentrations 7

Duration:

72 h

Dose descriptor:

EC90

Effect conc.:

48.8 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

other: yield

Effect concentrations 8

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

7.88 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

other: yield

Details on results:

- Observation of abnormalities (for algal test): the only found abnormalities were a low cell density in the 10 mg/L treatment group
- Dissolution behaviour: no remarkable observations

Results with reference substance (positive control):

The ErC50 (72 h) of the control substance potassium dichromate was 0.91 mg/L (Date of the last control experiment: 22 Feb 2010)