Cyclopentadecanone

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

Study period:

30 September 2016 to 6 December 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

2004

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

2008

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: Guidance document on aquatic toxicity testing of difficult substances and mixtures, OECD series on testing and assessment number 23

Version / remarks:

2000

Deviations:

not applicable

GLP compliance:

yes

Specific details on test material used for the study:

- Appearance: Colourless to very pale yellowish solid
- Test item storage: In refrigerator (2-8°C)
- Solubility in water: Insoluble
- Stability in water: Stable

Analytical monitoring:

yes

Details on sampling:

- Concentrations: All test concentrations and the control at the start and the end of the test (t=0h and t=48h).
- Sampling method: A volume of 800 μL taken from the approximate centre of the test vessels. At the end of the exposure period, the replicates were pooled at each concentration before sampling.
- Sample storage conditions before analysis: Not applicable, samples were transferred to the analytical laboratory at the Test Facility and analysed on the day of sampling.

Vehicle:

no

Details on test solutions:

Preparation of test solutions started with a loading rate of 100 mg/L applying a three-day period of magnetic stirring to ensure maximum dissolution of the test item in medium. Thereafter, the aqueous Saturated Solution (SS) was collected by means of filtration through a 0.45 μm membrane filter (RC55, Whatman) and used as the highest test concentration. Lower test concentrations were prepared by subsequent dilutions of the SS in test medium. All test solutions were clear and colorless at the end of the preparation procedure. Any residual volumes were discarded.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Strain/clone: Straus, 1820.
- Source: In-house laboratory culture with a known history.
- Age at study initiation: < 24 hours (at least third generation, obtained by a cyclical parthenogenesis under specified breeding conditions).
- Age of parental stock: > 2 weeks
- Validity of batch: Daphnids originated from a healthy stock, 2nd to 5th brood, showing no signs of stress such as mortality >20%, presence of males, ephippia or discoloured animals and there was no delay in the production of the first brood.
- Feeding during test: No

ACCLIMATION
- Acclimation period: No.

BREEDING
- Start of each batch: With newborn daphnids, i.e. less than 3 days old, by placing about 250 of them into 5 litres of medium in an all-glass culture vessel.
- Maximum age of the cultures: 4 weeks.
- Renewal of the cultures: After 7 days of cultivation half of the medium twice a week.
- Temperature of medium: 18 - 22 °C
- Feeding: Daily, a suspension of fresh water algae.
- Medium: M7, as prescribed by Dr. Elendt-Schneider (Elendt, B.-P., 1990: Selenium deficiency in Crustacea. An ultrastructural approach to antennal damage in Daphnia magna Straus. Protoplasma 154, 25-33).

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

180 mg/L (as CaCO3)

Test temperature:

19 - 20 °C

pH:

7.8 - 8.0

Dissolved oxygen:

8.6 - 9.4 mg/L

Nominal and measured concentrations:

- Nominal concentrations: 0 (control), 10, 18, 32, 56 and 100% of a saturated solution prepared at a loading rate of 100 mg/L.
- Measured concentrations (average): n.d., 0.056, 0.12, 0.19, 0.31, 0.54 mg/L.

See 'Any other information on materials and methods incl. tables' for more detail on measured concentrations.

Details on test conditions:

TEST SYSTEM
- Test vessel: 60 mL, all-glass, containing 50 mL of test solution
- Aeration: No
- No. of organisms per vessel: 5
- No. of vessels per concentration: 4
- No. of vessels per control: 4
- Introduction of daphnids: Within 10 minutes after preparation of the test solutions.

TEST MEDIUM / WATER PARAMETERS
- Test medium: Adjusted ISO medium consisting of tap water purified by Reverse Osmosis (RO-water, GEON Waterbehandeling, Berkel-Enschot, The Netherlands) containing the following chemicals (analytical grade): CaCl2·2H2O: 211.5 mg/L; MgSO4·7H2O: 88.8 mg/L; NaHCO3: 46.7 mg/L; KCl 4.2 mg/L.
- Culture medium different from test medium: Yes, adjusted ISO medium vs. Medium M7
- Intervals of water quality measurement: pH at the beginning and at the end of the test, for all concentrations and the control; Dissolved oxygen at the beginning and at the end of the test, for all concentrations and the control. In addition after 24 hours, immediately after counting the immobilized daphnids the oxygen level was measured in one of the replicates containing the highest test concentration; Temperature continuously in a temperature control vessel, beginning at the start of the test.

OTHER TEST CONDITIONS
- Adjustment of pH:
- Photoperiod: 16 hours photoperiod daily

EFFECT PARAMETERS MEASURED
Immobility (including mortality) after 24 hours and at 48 hours exposure.

TEST CONCENTRATIONS
- Range finding study: yes (combined range-finding / limit test)
- Test concentrations: 0 (control), 1.0, 10 and 100% of a saturated solution prepared at a loading rate of 100 mg/L.
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

yes

Remarks:

potassium dichromate (test performed September 2017)

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.18 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mobility

Remarks on result:

other: 95% CI: 0.15 - 0.20 mg/L

Details on results:

- Mortality of control: No
- Any observations that might cause a difference between measured and nominal values: No
- Effect concentrations exceeding solubility of substance in test medium: No

Reported statistics and error estimates:

The 24 and 48h-EC50-values were calculated from the weibits of the percentages of affected daphnids and the logarithms of the corresponding average test item concentrations using the maximum likelihood estimation method. ToxRat Professional v 3.2.1 (ToxRat Solutions® GmbH, Germany) was used to perform the analyses.

DETAIL ON RESULTS

Table: Incidence of Immobility

Average measured conc. (mg/L)	Immobility		Cumulative immobility (%)
	t=24h	t=48h
0 (control)	0/20	0/20	0
0.056	0/20	1/20	5
0.12	3/20	3/20	15
0.19	4/20	11/20	55
0.31	14/20	20/20	100
0.54	20/20	20/20	100

Validity criteria fulfilled:

yes

Conclusions:

The 48-h EC50 in Daphnia magna is 0.18 mg/L based on geomean measured concentrations.

Executive summary:

An acute toxicity test to Daphnia magna was performed according to OECD guideline No. 202 and in compliance with GLP criteria. In addition, procedures were based on the test methods described in the OECD series on testing and assessment number 23, 2000.

Twenty daphnids per group (four replicates, five daphnids per replicate) were exposed to a control and to 10, 18, 32, 56 and 100% of the SS for 48 hours under static conditions. Samples for analytical confirmation of exposure concentrations were taken at the start and at the end of the test. At the start of the test, the actual measured test concentrations were 0.071, 0.17, 0.28, 0.45 and 0.76 mg/L in 10, 18, 32, 56 and 100% of the SS, respectively. At the end of the 48-hour exposure period these concentrations had decreased to 46-64% of the initial concentrations. Based on these results, the average exposure concentrations were calculated to be 0.056, 0.12, 0.19, 0.31 and 0.54 mg/L and used to determine the EC-values. Immobility of daphnids was recorded after 24 hours and at 48 hours exposure. The study met the acceptability criteria and was considered valid.

After 48 hours exposure percentages immobility were recorded to be 5, 15, 55 at the test concentrations of 0.056, 0.12 and 0.19 mg/L, respectively. Immobility was 100% at the two highest test concentrations. A clear dose-response was obtained and the responses recorded in this test allowed for reliable determination of an EC50. In conclusion, the 48h-EC50 for Daphnia magna was 0.18 mg/L based on average exposure concentrations (95% confidence interval between 0.15 and 0.20 mg/L).

Description of key information

An acute toxicity test to Daphnia magna was performed according to OECD guideline No. 202 and in compliance with GLP criteria. In addition, procedures were based on the test methods described in the OECD series on testing and assessment number 23, 2000.

Twenty daphnids per group (four replicates, five daphnids per replicate) were exposed to a control and to 10, 18, 32, 56 and 100% of the SS for 48 hours under static conditions. Samples for analytical confirmation of exposure concentrations were taken at the start and at the end of the test. At the start of the test, the actual measured test concentrations were 0.071, 0.17, 0.28, 0.45 and 0.76 mg/L in 10, 18, 32, 56 and 100% of the SS, respectively. At the end of the 48-hour exposure period these concentrations had decreased to 46-64% of the initial concentrations. Based on these results, the average exposure concentrations were calculated to be 0.056, 0.12, 0.19, 0.31 and 0.54 mg/L and used to determine the EC-values. Immobility of daphnids was recorded after 24 hours and at 48 hours exposure. The study met the acceptability criteria and was considered valid.

After 48 hours exposure percentages immobility were recorded to be 5, 15, 55 at the test concentrations of 0.056, 0.12 and 0.19 mg/L, respectively. Immobility was 100% at the two highest test concentrations. A clear dose-response was obtained and the responses recorded in this test allowed for reliable determination of an EC50. In conclusion, the 48h-EC50 for Daphnia magna was 0.18 mg/L based on average exposure concentrations (95% confidence interval between 0.15 and 0.20 mg/L).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.18 mg/L