cyclohexadecanone

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:

27 - 29 Mar 2001

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:

Apr 1984

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

Dec 1992

GLP compliance:

yes (incl. QA statement)

Remarks:

Niedersächsisches Umweltministerium, Hannover, Germany

Analytical monitoring:

yes

Details on sampling:

- Concentrations: control, limit concentration 100 mg/L (nominal concentration)
- Sample storage conditions before analysis: if necessary, samples were stored at 7 ± 2 °C until analysis

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: a stock solution of 100 mg/L (nominal concentration) was prepared in dilution water, which was subject to a 30 min dispersion treatment (ultraturrax at 8500 rpm) and then filtered with a 45 µm single-use filter after dispersion
- Controls: yes, dilution water
- Evidence of undissolved material: no, the test item was clearly dissolved throughout exposure.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Strain/clone: Clone 5

ACCLIMATION
- Acclimation period: 2 h in dilution water
- Acclimation conditions (same as test or not): same

METHOD FOR PREPARATION AND COLLECTION OF EARLY INSTARS OR OTHER LIFE STAGES:
2 - 24 h old daphnids were used for the definitive study. They were obtained by removing the mother animals twice within 22 h.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

261 mg/L CaCO3

Test temperature:

20 ± 2 °C

pH:

7.61 - 7.75

Dissolved oxygen:

7.81 - 8.59 mg/L

Nominal and measured concentrations:

nominal: control, and 100 mg/L
measured: control, and 0.19 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 50 mL glass beakers
- size, headspace, fill volume: Size: 50 mL, inner diameter = 5 cm, height = 8 cm; Headspace: 30 mL; Fill volume: 20 mL
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: according to EEC 92/69 L383A C.2.
- Culture medium different from test medium: yes, culture medium = Elendt M4 (1990), modified to a total hardness of 160 to 180 mg/L CaCO3, test medium = dilution water
- Intervals of water quality measurement: the water parameters of the dilution (pH, dissolved O2, temperature, conductivity, total hardness) was measured before test start. The water parameters of the test (pH, dissolved O2) were measured at the beginning of the test in one replicate of test and control and after 48 h in all replicates per concentration and control. Temperature was measured continuously.

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 h light/8 h dark cycle
- Light intensity: diffuse light, 1.5 - 5 µmol * m-2 * s

EFFECT PARAMETERS MEASURED:
- % immobility: after 24 h and 48 h

RANGE-FINDING STUDY
- Test concentrations: First preliminary test: 1:1, 1:10; 1:100 dilutions of the stock solution of 100 mg/L; Second preliminary test: 100 mg/L stock solution with two different dispersion treatments (10 min ultrasonic treatment at room temperature or 30 min ultraturrax at 8500 rpm)
- Results used to determine the conditions for the definitive study: yes, based on the results of the preliminary tests a limit test with a saturated stock solution was performed. Two preliminary range finding tests were conducted under static conditions. In the first preliminary test three dilutions of a saturated stock solution (1:1, 1:10; 1:100, NON-GLP-state) were prepared. For the stock solution 100 mg/L was weighed out. The stock solution was stirred 24 h and filtered with 45 µm filters before use. The second preliminary test was conducted with two different dispersion treatments of the stock solution 100 mg/L: 10 min. ultrasonic treatment at room temperature and 30 min treatment with an ultraturrax at 8500 rpm. Both solutions were filtered with 45 µm filters before use.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 0.19 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Behavioural abnormalities: no
- Mortality of control: 0%
- Any observations that might cause a difference between measured and nominal values: no, the test item was clearly dissolved throughout exposure

Results with reference substance (positive control):

- Results with reference substance valid? yes
- Relevant effect levels: EC50 (24 h) = 2.1 mg/L potassium dichromate

The effect concentration was expressed as the mean measured saturated limit concentration.

Validity criteria fulfilled:

yes

Conclusions:

EC50 (48 h) > 0.19 mg/L (mean measured saturated concentration, limit test at a nominal concentration of 100 mg/L, OECD 202, Daphnia magna)

Description of key information

EC50 (48 h) > 0.19 mg/L (mean measured saturated concentration, limit test at a nominal concentration of 100 mg/L, OECD 202, Daphnia magna)

Additional information

There is one GLP certified guideline study available, which assessed the acute immobilisation of the test substance to aquatic invertebrates according to the OECD guideline 202.

In a static test Daphnia magna was exposed to the nominal limit concentration of 100 mg test substance/L for 48 h. The limit concentration was based on a saturated stock solution.

The test substance was analytically verified by GC-FID at the limit concentration and control at 0 h (fresh media) and 48 h (old media). The measured concentration of the test item was 0.19 mg/L at 0 h and 0.18 mg/L at 48 h. Test concentrations are based on the measured initial concentration of the test solution.

No immobilization was observed at the tested limit concentration and the 48 h EC50 was therefore > 0.19 mg/L (measured).