5-hexyldihydro-5-methylfuran-2(3H)-one

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2015-08-06 and 2015-10-08

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

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 1.25, 2.50, 5.00, 10.0, 20.0 mg/L and control
- Sampling method: At the start of the exposure intervals (0 and 24 hours), sampling was carried out after preparation of the test concentrations. At the end of the exposure intervals (24 and 48 hours), samples were taken directly from the test vessels.
- Sample storage conditions before analysis: at room temperature

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method:A stock solution of 20.0 mg/L of the test item was prepared one day before the start of each exposure interval (at -24 and 0 hours). For this purpose, 44.0 µL of the test item (density of the test item taken into account) were directly introduced by pipette into a 2 L glass flask, completely filled with the dilution water (approximately 2065 mL of ISO test water as specified below) below the water surface while stirring.
- Controls: Dilution water without test item tested under the same conditions as the test groups

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Strain: Daphnia magna STRAUS
- Age at study initiation: 2 to 24 hours old
- Method of breeding: In glass vessels (2 - 3 L capacity) with approximately 1.8 L culture medium, at 20 ± 2°C, in an incubator, 16 h illumination, light intensity of max. 20 µE * mE-2 * sE-1
- Feeding during test: no

ACCLIMATION
- Acclimation period: 2 hours
- Acclimation conditions: same as test (in dilution water)

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

none

Test temperature:

target: 18-22°C, constant within +/- 1°C

pH:

- Start of exposure interval (0 hours): 7.87 (control), 7.74-7.83 (test item)
- Start of exposure interval (24 hours): 7.85 (control), 7.71-7.81 (test item)
- End of exposure interval (24 hours): 7.39-7.55 (control), 7.41-7.99 (test item)
- End of exposure interval (48 hours): 7.57-7.66 (control), 7.24-7.66 (test item)

Dissolved oxygen:

- Start of exposure interval (0 hours): 9.10 (control), 8.12-8.98 (test item)
- Start of exposure interval (24 hours): 9.15 (control), 8.22-8.98 (test item)
- End of exposure interval (24 hours): 8.07-8.32 (control), 6.18-8.43 (test item)
- End of exposure interval (48 hours): 8.26-8.68 (control), 7.04-8.46 (test item)

Salinity:

not applicable

Nominal and measured concentrations:

nominal: 1.25, 2.50, 5.00, 10.0, 20.0 mg/L
measured (start of exposure interval): 1.06, 2.11, 3.77, 7.37, 16.1 mg/L (0 hours); 1.20, 2.39, 4.19, 8.71, 17.0 mg/L (24 hours)
measured (end of exposure interval): 0.860, 1.90, 3.87, 7.21, 14.2 mg/L (24 hours); 1.05, 2.07, 4.31, 7.94, 15.6 mg/L (48 hours)

Details on test conditions:

TEST SYSTEM
- Test vessel: Sealed glass flasks
- Type: closed (with screw caps made from polypropylene)
- size, headspace, fill volume: 4.5 (ID) x 9.5 (H) cm, without headspace, 130 mL test volume
- Renewal rate of test solution (frequency): daily
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- ISO Test water, according to OECD 202,
- Culture medium different from test medium: Elendt M4, according to Elendt (1990), modified to a total hardness of 160 to 180 mg CaC03/L, is used as culture medium.
- Intervals of water quality measurement: at the start of exposure intervals (0 and 24 hours) and at the end of the exposure intervals (24 and 48 hours)

OTHER TEST CONDITIONS
- Photoperiod: 16/8 h light/dark cycle (target)
- Light intensity: max. 20 µE x mE-2 x sE-1 (1340 lx) (target)

EFFECT PARAMETERS MEASURED:
- Determination of immobilisation after 24 and 48 hours

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Range finding study
- Test concentrations: 1.00, 10.0, 100 mg/L
- Results used to determine the conditions for the definitive study: The following immobilisation rates (%) were determined at 1.00, 10.0 and 100.0 mg/L after 24 h exposure: 0%, 20% and 100%, respectively. After an expsoure period of 48 hours, 0%, 80% and 100% immobilisation was observed for 1.00, 10.0 and 100.0 mg/L, respectively.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

48 h

Dose descriptor:

EC10

Effect conc.:

1.04 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95%CL: < 1.04 - 1.94

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

2.98 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CL: 2.50-3.61

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

7.79 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

1.04 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

2.11 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

EC10

Effect conc.:

1.68 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CL: < 1.04-3.07

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

5.59 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CL: 3.43-9.95

Duration:

24 h

Dose descriptor:

EC100

Effect conc.:

> 15.7 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

All test concentrations were visually clear throughout the exposure period.

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- The EC50 value determined after 24 hours for the most recent of the monthly performed reference tests was 2.00 mg/L (CL: 1.83 - 2.19 mg/L).

Reported statistics and error estimates:

EC10- and EC50-values (after 24 and 48 hours) were calculated by sigmoidal dose-response regression. The respective 95 % confidence limits were calculated from the standard error and the t-distribution. No mathematical calculation was performed for the EC100 values (after 24 and 48 hours) and for the NOEC and LOEC (after 48 hours).

Immobilisation Rates after 24 and 48 h of Exposure in the Definitive Test

(n = 20, divided into 4 replicates with 5 daphnids each)

Test substance		Immobilisation [%]
nominal concentration [mg/L]	Geometric mean measured concentration [mg/L]	24 h					48 h
		Replicates					Replicates
		1	2	3	4	MV	1	2	3	4	MV
20	15.7	80	60	100	80	80	100	100	100	100	100
10	7.79	40	100	40	60	60	100	100	100	100	100
5	4.03	40	80	0	40	40	60	80	60	100	75
2.5	2.11	20	0	0	40	15	40	0	0	60	25
1.25	1.04	0	0	0	0	0	20	20	0	0	10
Control		0	0	0	0	0	0	0	0	0	0

 

 

Measured Concentrations and Percent of the Nominal Concentrations of the Test Item during the Definitive Test

Sampling date	2015-08-12 0 hours Start of the exposure interval		2015-08-13 24 hours End of the exposure interval		2015-08-13 24 hours Start of the exposure interval		2015-08-14 48 hours End of the exposure interval
Nominal test item concentration [mg/L]	Test substance								Geometric mean
	Meas. conc. [mg/L]	%	Meas. conc. [mg/L]	%	Meas. conc. [mg/L]	%	Meas. conc. [mg/L]	%	Meas. conc. [mg/L]	%
20	16.1	81	14.2	71	17	85	15.6	78	15.7	79
10	7.37*	74	7.21	72	8.71	87	7.94	79	7.79	78
5	3.77*	75	3.87	77	4.19	84	4.31	86	4.03	81
2.5	2.11	84	1.9	76	2.39	96	2.07	83	2.11	84
1.25	1.06	85	0.86	69	1.2	96	1.05	84	1.04	83
Control	< LOQ		< LOQ		< LOQ		< LOQ

Meas. conc. = measured concentration of the test item, preconcentration and dilution factor taken into account

% = percent of the nominal concentration of the test item

LOQ = limit of quantification of the analytical method (0.25 mg/L of the test item)

* = reanalysed, mean value of 3 replicates, dilution factor taken into account

Validity criteria fulfilled:

yes

Conclusions:

In a 48 h semi-static toxicity test with Daphnia magna the EC50 value based on mobility of the test substance was found to be 2.98 mg/L.

Executive summary:

In the acute immobilisation test with Daphnia magna (STRAUS), the effects of the test item were determined according to OECD 202 (2004). The study was conducted in a closed system (sealed glass flasks) without headspace under static conditions over a period of 48 h with the following concentrations: 1.25 - 2.50 - 5.00 - 10.0 - 20.0 mg/L (nominal). Twenty daphnids were exposed to each concentration level and the control. The concentrations of the test item were analytically verified via GC-MS at the start (0 and 24 hours) and at the end of the exposure intervals (24 and 48 hours) in all concentration levels and the control. Since the measured test item concentrations did not remain within +/- 20% of the nominal concentrations, the effect values based on the geometric mean measured concentrations of the test item calculated as follows: 1.04, 2.11, 4.03, 7.79 and 15.7 mg/L. Based on the geometric mean measured concentrations of the test item, the 48 -hour EC50 for Daphnia magna was 2.98 mg/L (95% CL: 2.50 - 3.61 mg/L). The NOEC after 48 hours was 1.04 mg/L. The LOEC after 48 hours was 2.11 mg/L.

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

Please refer to attached "Read-across justification".

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

2.98 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CL: 2.50-3.61

Description of key information

EC50 (48 h) = 2.98 mg/L for Daphnia magna (geom. mean measured concentration, based on read-across approach).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

2.98 mg/L

Additional information

For the test substance no short-term toxicity test to aquatic invertebrates are available.

Therefore, an analogy approach to the read-across substance Reaction mass of trans-5 -hexyldihydro-4 -methylfuran-2(3H)-one and cis-5 -hexyldihydro-4 -methylfuran-2(3H)-one is applied.

In an acute immobilisationtest with Daphnia magna (STRAUS), the effects of the read-across substance were determined according to OECD 202 (2004). The study was conducted in a closed system without headspace using the following concentrations: 1.25, 2.50, 5.00, 10.0 and 20.0 mg/L (nominal). After 24 and 48 hours, the daphnids were observed for signs of immobility. As a result, the EC50 value of the read-across substance was found to be 2.98 mg/L based on the geometric mean measured concentration.