Butyl 3-hydroxybutyrate

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

Study period:

10 to 13 June 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted under the appropriate guideline following GLP methodology.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

Principles of method if other than guideline:

not applicable

GLP compliance:

yes

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
not applicable

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 100 mg/L (Limit Test) based on preliminary range-finding results

Vehicle:

no

Details on test solutions:

Test concentrations were prepared by addition of the appropriate weight of the sample added to test media and made up to the mark in volumetric
flasks to give the required concentration.

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Common name: Pseudokirchneriella subcapitata
- Strain: CCAP 278/4
- Source (laboratory, culture collection): Culture Collection of Algae and Protozoa, SAMS Research Services Ltd, Scottish Marine Institute, Scotland, UK
-Inoculum level adjusted to give an initial cell density of 1 x 10(4) cells/ml
ACCLIMATION
- Acclimation period: no
- Culturing media and conditions (same as test or not): yes

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 d

Hardness:

not provided- culture medium according to OECD guidelines

Test temperature:

22.2 to 23.0°C

pH:

control: 8.01 to 7.42
100 mg/L concentration: 7.64 to 7.33

Dissolved oxygen:

not available

Salinity:

not applicable

Nominal and measured concentrations:

range finding nonmial concentrations were 0.1, 1.0, 10, and 100 mg/L; definitive nominal concentration was 100 mg/L reported as 63.1 mg/L mean measured or 63.4% (percent recovery).

Details on test conditions:

TEST SYSTEM
- Test vessel: 250 ml conical flask (Erlenmeyer)
- Material, size, headspace, fill volume: 100 ml
- Aeration: no
- Initial cells density: 1 x 10(4)
- Control end cells density: 1 x 10(4)
- No. of vessels per concentration (replicates):3 replicates at each test concentration
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: deionised water/sterilised by autoclaving at 120°C for 15 minutes then adding a sterile nutrient stock solution and adjusting the pH to 8.0 +/- 0.1
-
- Culture medium different from test medium: no
- Intervals of water quality measurement: after initiation and at test termination on pooled replicates for test concentrations and the control


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: haemocytometer and microscope


TEST CONCENTRATIONS
- - Range finding study: yes
- Test concentrations: 0.1, 1.0, 10 and 100 mg/L
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

not required

Duration:

48 h

Dose descriptor:

EC10

Effect conc.:

> 63.1 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

not specified

Basis for effect:

cell number

Duration:

48 h

Dose descriptor:

EC20

Effect conc.:

> 63.1 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

not specified

Basis for effect:

cell number

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 63.1 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

not specified

Basis for effect:

cell number

Duration:

48 h

Dose descriptor:

EC10

Effect conc.:

> 63.1 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

not specified

Basis for effect:

growth rate

Duration:

48 h

Dose descriptor:

EC20

Effect conc.:

> 63.1 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

not specified

Basis for effect:

growth rate

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 63.1 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

not specified

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 63.1 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

not specified

Basis for effect:

cell number

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 63.1 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

not specified

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

ca. 63.1 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

not specified

Basis for effect:

cell number

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

ca. 63.1 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

not specified

Basis for effect:

growth rate

Details on results:

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

Results with reference substance (positive control):

not required

Validity criteria fulfilled:

yes

Conclusions:

The study was conducted as a Limit Test based upon preliminary range-finding results. The study followed OECD 201 and GLP and was therefore deemed valid and reliable. The validity criteria according to OECD 201 was fulfilled. The EC50 values for yield and growth inhibition were both > 63.1 mg/L (mean measured) at test termination.

Executive summary:

A study was conducted to determine the the acute toxicity of n-Butyl-2 -hydroxybutyrate to the freshwater algae, Pseudokirchneriella subcapitata in a 72 hour exposure following OECD 201. A preliminary range-finding study with concentrations of 0.1, 1.0, 10 and 100 mg/L showed no significant change in yield or growth of algal cells compared to the control, so a limit test at 100 mg/L was conducted following guideline recommendations. Analytical measurement of the exposure solutions showed mean measured concentrations that were 63.4% of nominal therefore all definitive test concentrations are reported as mean measured concentrations.

The 72-hr EC50 value was estimated to be >63.1 mg/L. The highest no observed effect concentration (NOEC) for both yield and growth inhibition was 63.1 mg/L

Description of key information

The study was conducted as a Limit Test based upon preliminary range-finding results.  The study followed OECD 201 and GLP and was therefore deemed valid and reliable.  The validity criteria according to OECD 201 was fulfilled.  The EC50 values for yield and growth inhibition were both > 63.1 mg/L (mean measured) at test termination.

Key value for chemical safety assessment

EC50 for freshwater algae:

63.1 mg/L

EC10 or NOEC for freshwater algae:

63.1 mg/L