6-methyloct-5-en-2-one

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study.

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

1989

Report date:

1989

Reference 2

Reference Type:

other: Calculation

Title:

Unnamed

Year:

2003

Report date:

2003

Reference 3

Reference Type:

study report

Title:

Unnamed

Year:

2003

Report date:

2003

Reference 4

Reference Type:

other: Calculation

Title:

Unnamed

Year:

2003

Report date:

2003

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: German standard DIN 38412, L 9

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

6-methylhept-5-en-2-one

EC Number:

203-816-7

EC Name:

6-methylhept-5-en-2-one

Cas Number:

110-93-0

IUPAC Name:

6-methylhept-5-en-2-one

Details on test material:

- Name of test material (as cited in study report): Methylheptenon
- Water solubility: 3.02 g/L

Sampling and analysis

Analytical monitoring:

no

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Strain: CHODAT (SAG 86.81)

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Test temperature:

21.3°C

pH:

7.58 - 9.19

Nominal and measured concentrations:

Nominal test concentration (mg/l):
10, 25, 50, 100, 250, 500, control, solvent control

Details on test conditions:

The number of cells were measured daily using fluorescence method at 300 - 780 nm (pulsed fluorometry)

TEST DESIGN
- 4 replicates per concentration

Results and discussion

Effect concentrations

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

116 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: effective concentration due to volatilisation

Details on results:

Due to a moderate volatility in an experiment using 100 mg and 200 mg of 6-methylhept-5-en-2-one, but without test organisms, the evaporation over 72 hours was observed. After 72 h approximately 37 % and 39 % of the test substance were evaporated (geometric mean of of all TOC values between 0 h and 96 h), respectively. Therefore, the ErC50(72h) can be corrected to be 116 mg/l based on 39% evaporation.
For the EbC50(72h) the effective value is 126 mg/l based on 39% evaporation.

Neither growth promotion nor autofluorescence were observed. The effect values for the endpoint growth rate are:
NOEC (72h) < 10 mg/l
ErC10 (72h) = 30.13 mg/l (95% confidence: 9.1-99.9 mg/l)

The effect values for the endpoint biomass are:
NOEC (72h) < 10 mg/l
EbC10 (72h) = 31.12 mg/l (95% confidence: 11.4-84.5 mg/l)
EbC50 (72h) = 208.20 mg/l (95% confidence: 71.3-607.7 mg/l)

In spite of the increased pH values after 96h in the treatments 10 and 25 mg/l a pH effect can be excluded, because the cell density and the growth rate, as relevant parameter, were not affected.

Reported statistics and error estimates:

The ECx values were calculated according to Tallarida and Jacob (1979).