4-methyl-4-phenylpentan-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

Study period:

26 Mar - 03 May 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)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Swiss Federal Office of Public Health, Consumer protection directorate, Notification authority for chemicals, Bern, Switzerland (16 Dec 2015)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: All test concentrations and the control at the start of the test and at the end of the test (after 48 h). The samples from the nominal test concentration of 4.6 mg/L and 10 mg/L were not analyzed because this concentration was below the determined NOEC.
- Sampling method: Duplicate samples were taken from all test media.
- Sample storage conditions before analysis: Frozen at -20 ± 5 °C immediately after sampling. Pre-experiments found that the test item was stable under these storage conditions.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A stock solution of 100 mg/L was prepared by dissolving 100.01 mg test item in 1000 mL test water by intense stirring during 30 min at room temperature. The lower test item concentrations were prepared in a series of dilution steps just before the start of the test.
- Controls: yes, test medium control
- Evidence of undissolved material: All test media were clear solutions throughout the test period.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Feeding during test: none
- Food type: The green algae Desmodesmus subspicatus SAG or a mixture of this algal suspension and a commercial fish diet (Tetra Min® Hauptfutter; TETRA-Werke, Melle, Germany) were used.
- Others: At the start of the test, the organisms used in the test were 6-24 hours old and were not first brood progeny.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

2.5 mmol/L or 250 as CaCO3

Test temperature:

20 - 21 °C

pH:

7.8 - 7.9 (control)
7.7 - 7.9 (test item concentrations)

Dissolved oxygen:

8.4 - 8.7 mg/L (control)
8.3 - 8.6 mg/L (test item concentrations)

Nominal and measured concentrations:

control, 4.6, 10, 22, 46 and 100 mg/L (nominal)
control, not analyzed, not analyzed, 19, 38 and 88 mg/L (geometric mean)

Details on test conditions:

TEST SYSTEM
Test vessel
- Type: open (covered with glass plates)
- Material, size, headspace, fill volume: 100 mL glass beakers was filled with 50 mL test medium; 50 mL headspace
- Aeration: no aeration (test water was aerated prior to the start of the study until oxygen saturation was reached)
- 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: test water (ISO test water) according to OECD guideline 202
- Alkalinity: 0.8 mmol/L
- Culture medium different from test medium: no data
- Intervals of water quality measurement: start and end of the test medium renewal periods, the pH values, dissolved oxygen concentrations and water temperature were determined in each treatment. At the same observation dates, the appearance of the test media was visually controlled and documented at the same time.

OTHER TEST CONDITIONS
- Photoperiod: 16 h light/8 h dark cycle and a 30 min transition period
- Light intensity: 15 - 17 μmol m-2 s-1

EFFECT PARAMETERS MEASURED:
- Immobilization after 24 and 48 h

RANGE-FINDING STUDY
- Test concentrations: control, 1.0, 10 and 100 mg/L
- Results used to determine the conditions for the definitive study: 0% immobilization in the control, 1.0 and 10 mg/L; 100% immobilization at 100 mg/L after 48 h

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

35 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% confidence limits could not be determined

Duration:

48 h

Dose descriptor:

other: EC0/ NOEC

Effect conc.:

19 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

88 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Other biological observations: Beside immobility no other adverse effects (symptoms) were observed.
- Mortality of control: 0%
- Any observations that might cause a difference between measured and nominal values: No remarkable observations were made concerning the appearance of the test media. All test media were clear solutions throughout the test.
- Other: Biological and analytical results are summarized in the tables 1-3 within the section "Any other information on results incl. tables"

Results with reference substance (positive control):

- Dose-response test: yes
- EC50 (24 h): 1.2 mg/L (sensitivity of the test organisms was within the range given by the guideline)

Reported statistics and error estimates:

The 24 h and 48 h EC50 (and the 95 % confidence limits) were calculated by Weibull Analysis. Statistical analysis was performed using ToxRat Professional®. The 24 h and 48 h NOEC, EC0 and EC100 were determined directly from the raw data.

Table 1: Biological Results: Effect of test item on the Mobility of Daphnia magna

Test Item Concentration [mg/L]		No. of Daphnids Tested	Immobilized Daphnids after 24 Hours		Immobilized Daphnids after 48 Hours
Nominal	Mean Measured		No.	[%]	No.	[%]
Control	Control	20	0	0	0	0
4.6	n.a.	20	0	0	0	0
10	n.a	20	0	0	0	0
22	19	20	0	0	0	0
46	38	20	11	55	18	90
100	88	20	20	100	20	100

n.a.: Not analyzed since below the NOEC determined in this test.

Table 2: Analytical Results: Results for Test Samples

Sampling Day/Sample Age	Nominal Concentration of Test Item cnom	Measured Concentration of Test Item x	Sample Preparation Factor F	Determined Concentration of Test Item c	% of Nominal Concentration
[d/h]	[mg/L]	[mg/L]		[mg/L]	[%]
0/0	Control	n.d.	2	< LOQ	n.a.
(fresh)	22	11.1	2	22.2	101
	46	22.8	2	45.7	99
	100	49.7	2	99.4	99
2/48	Control	n.d.	2	< LOQ	n.a.
(aged)	22	8.46	2	16.9	77
	46	15.5	2	31.1	68
	100	38.5	2	77.1	77

n.d. = no test item detected

n.a. = not applicable

LOQ: 0.6 mg/L

Table 3: Analytical Results Test item concetration nominal and actual

Nominal Test Item Concentration	Measured Test Item Concentration at the Start (0 Hours)	Measured Test Item Concentration at the End (48 Hours)	Mean Measured Concentration of the Test Item (Geometric Mean)
[mg/L]	[mg/L]	[mg/L]	[mg/L]
22	22.2	16.9	19
46	45.7	31.1	38
100	99.4	77.1	88

 

Table 4: Validity criteria

Criterion from the guideline	Outcome	Validity criterion fulfilled
In the control, including the control containing the solubilising agent, not more that 10% of the daphnids should have been immobilized.	0%	yes
The dissolved oxygen concentration at the end of the test should be ≥ 3 mg/L in control and test vessels.	8.3 - 8.5 mg/L	yes

Validity criteria fulfilled:

yes

Remarks:

For further details please refer to “Any other information on results incl. tables”.

Conclusions:

The study was performed according to OECD 202, C.2 guideline and GLP. The EC50 (48 h) was calculated to be 35 mg/L based on the geometric mean measured concentration.

Description of key information

EC50 (48 h): 35 mg/L (Daphnia magna, geometric mean measured concentrations, OECD 202)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

35 mg/L

Additional information

One experimental study is available investigating the short-term effects of the substance to aquatic invertebrates. The study was performed according to the OECD 202 (GLP) with the water flea Daphnia magna under static conditions. The nominal test item concentrations tested were 4.6, 10, 22, 46 and 100 mg/L. The initial measured test item concentrations were in the range of 99 to 101% of the nominal values. Thus, the correct dosage of the test item was confirmed. A low decrease of the initial test item concentration was observed after the exposure period of 48 hours. For the aged samples the test item concentrations were in the range of 68 to 77% of the nominal values. Therefore, the mean measured test item concentrations over the test period of 48 hours were calculated as the geometric mean of all concentrations measured at the start and end of the test resulting in 19, 38 and 88 mg/L (the three highest nominal concentrations). Immobilisation of Daphnia magna was observed resulting in an EC50 (48 h) of 35 mg/L based on geometric mean measured concentrations.