Oxacycloheptadecan-2-one

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

7 October 2016 to 15 December 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Version / remarks:

1992

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

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, 2000.

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 first and the last 24-hour renewal period
- Sampling method: A volume of 800 μL taken from the approximate centre of the test vessels
- 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.

Details on test solutions:

- Range-finding test: In the range-finding test, another, yet similar batch (40191) was used than in the final test. Test solutions were prepared once and 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. The obtained aqueous mixture was allowed to settle for a period of 15-35 minutes. Thereafter, the saturated solution was collected by means of siphoning and used as the highest test concentration. Lower test concentrations were prepared by subsequent dilutions of the saturated solution in test medium. All test solutions were clear and colorless at the end of the preparation procedure.
- Final test: Test solutions were prepared daily and started with a loading rate of 100 mg/L. Test solutions prepared for day 0 and day 1 were magnetically stirred for three days to ensure maximum dissolution of the test item in medium. Test solutions prepared for day 2 and day 3 were magnetically stirred for two and one day(s), respectively. All obtained aqueous mixtures were allowed to settle for a period of 15-35 minutes. Thereafter, the saturated solutions were collected by means of siphoning and used as the highest test concentration. Lower test concentrations were prepared by subsequent dilutions of the saturated solution 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):

Cyprinus carpio

Details on test organisms:

TEST ORGANISM
- Common name: Carp
- Source: Zodiac, proefacc, "De Haar Vissen", Wageningen University and Research Centre, The Netherlands.
- Length at study initiation: 2.6 ± 0.3 cm
- Weight at study initiation: 0.21 ± 0.10 g
- Method of breeding: F1 from a single parent-pair bred in UV-treated water.

ACCLIMATION
- Acclimation period: At least 12 days after delivery.
- Acclimation conditions: Same as test
- Type and amount of food during acclimation: Pelleted fish food (Cyprico Crumble Excellent (300-500 um), Coppens International bv, Helmond, The Netherlands).
- Feeding frequency during acclimation: Daily
- Health during acclimation: In the batch of fish used for the test, mortality during the seven days prior to the start of the test was less than 5%.

FEEDING DURING TEST
No feeding from 24 hours prior to the test and during the total test period.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

180 mg/L as CaCO3

Test temperature:

21 - 22 °C

pH:

7.7 - 8.2

Dissolved oxygen:

6.5 - 9.7 mg/L

Nominal and measured concentrations:

- Nominal concentrations: 0 (control), 4.6, 10, 22, 46 and 100% of a saturated solution prepared at a loading rate of 100 mg/L.
- Measured concentrations (average): n.d., 0.0098, 0.026, 0.052, 0.19 and 1.1 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: All-glass, containing 5 litres of test solution
- Aeration: No
- Renewal rate of test solution: Daily
- No. of organisms per vessel: 7
- No. of vessels per concentration: 1
- No. of vessels per control: 1
- Biomass loading rate: 0.29 g fish/L
- Introduction of fish: Within 30 minutes after preparation of the test media from a holding tank with comparable water quality parameters and pH and temperature differences between test and holding tank media of less than 0.5 unit and 1.0 °C.
- Euthanasia: At the end of the test the surviving fish were rapidly killed by exposing them to ca. 1.2% ethylene glycol monophenylether in water.

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Adjusted ISO medium, formulated using RO-water (tap-water purified by reverse osmosis; GEON Waterbehandeling, Berkel-Enschot, The Netherlands) with the following composition: 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: No
- Intervals of water quality measurement: Measurements of dissolved oxygen, pH and temperature occurred daily in all vessels with surviving fish, beginning at the start of the test (day 0).

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 hours photoperiod daily.

EFFECT PARAMETERS MEASURED
Fish were checked for mortality and other effects at 4.75, 24, 48, 72 and 96 hours following the start of exposure. In addition, every afternoon from day 0 to observe for any dead or severely distressed fish. Dead fish were removed when observed.

TEST CONCENTRATIONS
- Range finding study : yes
- Test concentrations: 0 (control), 1.0, 10 and 100% of a saturated solution prepared at a loading rate of 100 mg/L. The range-finding test was performed under static conditions without renewal of test concentrations.
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

yes

Remarks:

pentachlorophenol (February 2017)

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 0.052 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mortality (fish)

Remarks on result:

other: Average measured concentrations determined as mathematical means of the geometric mean of the concentrations of test substance measured in the samples taken during the first and the last renewal period.

Details on results:

- Mortality in test media: At average measured test concentrations of 0.052 (solubility limit in test medium), 0.19 and 1.1 mg/L cumulative mortalities were 29%, 29% and 57%, respectively. Mortality at these concentrations was first observed after 72 hours exposure.
- Mortality of control: No
- Other adverse effects control: No
- Clinical observations: One of 3 remaining fish after 96 hours exposure to an average measured concentration of 1.1 mg/L showed discolouration. No other clinical effects were observed.
- Effect concentrations exceeding solubility of substance in test medium: Yes (see 'Any other information on materials and methods incl. tables').

Results with reference substance (positive control):

- Results with reference substance valid? yes
- Dose-response test: yes (test concentrations: 0.10, 0.22 and 0.46 mg/L)
- 96-h EC50: 0.32 mg/L (95% C.L. 0.22 - 0.46 mg/L). This effect was already reached within 24 hours of exposure.
- Other: The range of the 96h-LC50 for carp is generally between 0.10 and 0.46 mg/L based on historical data of reference tests performed approximately every 3 months from April 1988 until the end of 2000, and annually since then. Hence, the sensitivity of carp originating from the present batch for PCP falls within the range of sensitivities generally observed during the past years.

Reported statistics and error estimates:

Not applicable. No LC50 could be calculated because the test item proved to be above the solubility limit of Oxacycloheptadecan-2-one in test medium.

Sublethal observations / clinical signs:

Table: Incidence of mortality and total mortality during the test

Average measured conc. (mg/L)	Cumulative mortality					Total mortality (%)
	4.75h	24h	48h	72h	96h
0 (control)	0	0	0	0	0	0
0.0098	0	0	0	0	0	0
0.026	0	0	0	0	0	0
0.052	0	0	0	2/7	2/7	29
0.19	0	0	0	2/7	2/7	29
1.1	0	0	0	3/7	4/7	57

Note: Mortality and clinical effects were seen only in concentrations at and above 0.052 mg/L

Validity criteria fulfilled:

yes

Remarks:

see 'Overall remarks'.

Conclusions:

The 96-h LC50 value is >0.052 mg/L in fish (C. carpio). The concentration of 0.052 mg/L is considered to be the limit of solubility in test medium.

Executive summary:

The acute toxicity to fish was examined in a study according to OECD TG 203 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.

A Saturated Solution (SS) was prepared at a loading rate of 100 mg/L and used as the highest concentration. Lower test concentrations were prepared by diluting the SS in test medium. Seven fish per group were exposed to a control and to 4.6, 10, 22, 46 and 100% of the SS for 96 hours under semi-static conditions (daily renewal). Samples for analytical confirmation of exposure concentrations were taken at the start and at the end of the first and the last renewal period. At the end of the second, third and last renewal periods undissolved test item was observed in the test solutions at 22, 46 and/or 100% of the SS. Based on these observations it can be concluded that test solutions at and above 22% of the SS contained concentrations above the solubility limit of test item in test medium during at least part of the 96h exposure period. Due to the general decrease of test item concentrations during the 24-hour renewal periods the average concentrations were calculated to be 0.0098, 0.026, 0.052, 0.19 and 1.1 mg/L. Concentrations at and above 0.052 mg/L were considered to be above the solubility limit in test medium. Mortality and clinical effects were recorded at 4.75, 24, 48 72 and 96 hours after start of exposure. The study met the acceptability criteria and was considered valid.

At average measured test concentrations of 0.052 (solubility limit in test medium), 0.19 and 1.1 mg/L cumulative mortalities after 96 hours exposure were 29%, 29% and 57%, respectively. Mortality at these concentrations was first observed after 72 hours exposure. The 96-h LC50 approximated an average concentration of 1.1 mg/L. As however this concentration is considered to be above the solubility limit of test item in test medium, the 96-h LC50 value is determined at >0.052 mg/L.

Description of key information

The acute toxicity to fish was examined in a study according to OECD TG 203 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.

A Saturated Solution (SS) was prepared at a loading rate of 100 mg/L and used as the highest concentration. Lower test concentrations were prepared by diluting the SS in test medium. Seven fish per group were exposed to a control and to 4.6, 10, 22, 46 and 100% of the SS for 96 hours under semi-static conditions (daily renewal). Samples for analytical confirmation of exposure concentrations were taken at the start and at the end of the first and the last renewal period. At the end of the second, third and last renewal periods undissolved test item was observed in the test solutions at 22, 46 and/or 100% of the SS. Based on these observations it can be concluded that test solutions at and above 22% of the SS contained concentrations above the solubility limit of test item in test medium during at least part of the 96h exposure period. Due to the general decrease of test item concentrations during the 24-hour renewal periods the average concentrations were calculated to be 0.0098, 0.026, 0.052, 0.19 and 1.1 mg/L. Concentrations at and above 0.052 mg/L were considered to be above the solubility limit in test medium. Mortality and clinical effects were recorded at 4.75, 24, 48 72 and 96 hours after start of exposure. The study met the acceptability criteria and was considered valid.

At average measured test concentrations of 0.052 (solubility limit in test medium), 0.19 and 1.1 mg/L cumulative mortalities after 96 hours exposure were 29%, 29% and 57%, respectively. Mortality at these concentrations was first observed after 72 hours exposure. The 96-h LC50 approximated an average concentration of 1.1 mg/L. As however this concentration is considered to be above the solubility limit of test item in test medium, the 96-h LC50 value is determined at >0.052 mg/L.