6-methylhept-5-en-2-one

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

No GLP. Test design issues, hence ECx values recalculated

Qualifier:

according to guideline

Guideline:

other: German standard DIN 38412, L11

GLP compliance:

no

Analytical monitoring:

no

Test organisms (species):

Daphnia magna

Details on test organisms:

- Test organism: the waterflea Daphnia magna STRAUS was used- Housing: 30 animals were kept together in 5 l glass beaker containing 2.1 l water at 21°C. The water was exchanged daily and a conductivity of 658 µS/cm, a Ca: Mg ratio of 5:1 and a Na:K ratio of 20:1 were measured. - The animals showed a reproduction rate of three animals per day. - Feeding: the animals were fed with the algae Scenedesmus subspicatus once a day.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test temperature:

21 °C

pH:

7.56 - 7.63

Dissolved oxygen:

8.2 - 8.6 mg/l

Nominal and measured concentrations:

Nominal test concentrations of (mg/l):58, 100, 180, 320, 580 and control

Details on test conditions:

After preparing a stock solution (1000 mg/l) 4x5 daphnids were used per concentration at a total test volume of 20 ml each. The test conditions corresponded to that in the stock culture. The test substance was added to the test water without any prior treatment. Subsequently, the daphnids were added to the water. As control test water without test substance was used. The several treatments were prepared according to the standard guideline and therefore, no measurements of oxygen, pH and temperature at the beginning of the exposure (0h) were performed. After 48h of exposure these parameters were determined:

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

74 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: effective concentration due to volatility

Details on results:

48 h EC0 58 mg/L (nominal) based on test material48 h EC100 320 mg/L (nominal) based on test materialDue 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 48 hours was observed. After 48 h approximately 33 % and 35 % of the test substance were evaporated (geometric mean of of all measured TOC values between 0 h and 48 h), respectively. Therefore, the EC50(48h) can be corrected to be 74 mg/l based on 35 % evaporation.

Reported statistics and error estimates:

Using the Spearman-Kärber method a EC50 (24h) of 168 mg/l and a EC50 (48h) of 114 mg/l was calculated.

Description of key information

Acute toxicity to daphnids was investigated in accordance with DIN 38 412 in a static test, not under GLP. Using the geometric mean of the EC0 of 58 mg/l and the EC100 of 320  mg/l a 48h EC50 of 114 mg/l could be calculated based on test material. 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 48 hours was observed. After 48 h approximately 33 % and 35 % of the test substance were evaporated (geometric mean of of all measured TOC values  between 0 h and 48 h), respectively. Therefore, the EC50(48h) can be corrected to be 74 mg/l based on 35 % evaporation.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

74 mg/L