2,6-Octadienal, 3,7-dimethyl-, acid-isomerized

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:

2017-08-14 to 2017-08-17

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)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 0.751 - 1.65 - 3.64 - 8.00 mg/L
- Sampling method: At the start of the exposure and at the renewal (0 and 24 hours), samples of the fresh media were taken after preparation of all WAFs and analyzed. At the renewal and at the end of the exposure (24 and 48 hours), samples of the 24-hours old media were taken directly from the test vessels.
- Sample storage conditions before analysis: All samples were stored at 6 ± 2 °C until sample preparation and at room temperature until the start of the analysis

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
Water accomodated fraction WAF:
- Method: An appropriate volume of the test item was introduced into the dilution water by pipette in brown glass flasks. Then shaken for 24 hours with 20 rpm at room temperature. After completion of shaking and following a separation phase of 1 hour of standing, the aqueous phase or WAF was removed from the approximate center of the water body by siphoning. The lowest loading level of nominal 0.342 mg/L was prepared from the WAF with the nominal loading of 0.751 mg/L by dilution with dilution water.
- Test loading: 0.751 - 1.65 - 3.64 - 8.00 mg/L
- Controls: Dilution water without test item incubated under the same conditions as the test groups.
- Evidence of undissolved material: visually clear throughout the exposure period.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Species: Daphnia magna (Straus), clone 5
- Age at test start: Less than 24 hours
- Breeding Conditions: fed at least 5 times per week ad libitum with a mix of unicellular green algae

ACCLIMATION
- Acclimation period: not necessary, because the composition of the dilution water was equivalent to the culture medium.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

160 to 180 mg CaCO3/L

Test temperature:

21.0 to 20.9 °C

pH:

pH at test start: 8.01 - 8.37;
pH at test end: 7.64- 8.00

Dissolved oxygen:

Dissolved oxygen concentration at test start: 8.49 to 8.75 mg/L;
Dissolved oxygen concentration at test end: 7.64 to 8.36 mg/L

Nominal and measured concentrations:

Nominal: 0.342 - 0.751 - 1.65 - 3.64 - 8.00 mg/L
Measured (fresh media, 0 hours): 0.133, 0.334, 1.05, 2.31, 4.97 mg/L; Old media (24h): 0.108, 0.208, 0.836, 2.14, 5.03

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass beakers
- Type: closed
- Material, size, headspace, fill volume: approximately 130 mL, filled up to the top with the test solutions, no headspace
- No. of organisms per vessel: 5 daphnids
- 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 OECD 202, Annex 3 (2004)
- Culture medium different from test medium: no
- Intervals of water quality measurement: 0 hours and 24 hours

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 h light : 8 h dark
- Light intensity: Diffuse light, light intensity of max. 1500 lx

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Immobility: immobilization was determined in all groups after 24 and 48 hours

VEHICLE CONTROL PERFORMED: yes

RANGE-FINDING STUDY
- Test concentrations: two non-GLP preliminary range finding tests: 1 -10-100 mg/L and 0.01 - 0.1 - 1 mg/L
- Results used to determine the conditions for the definitive study: first preliminary range finding test: immobilisation at 48 h: 100% for 100 and 10 mg/L; 65% for 1 mg/L; second preliminary range finding test: immobilisation at 48 h: 15% for 1 mg/L; 0% for 0.1 and 0.01 mg/L

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

4.31 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% confidence limits: 1.86-7.98 mg/L

Duration:

48 h

Dose descriptor:

EL10

Effect conc.:

3.38 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EL100

Effect conc.:

8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOELR

Effect conc.:

1.65 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Signs of intoxication after 48 hours: Other adverse effects except immobility did not appear
- Analytical results: The measured concentrations of the test item based on two main constituents in the old media (24 and 48 hours) were in the range of 62 to 123% of the initially measured concentrations.

Results with reference substance (positive control):

In the most recent test with the reference item potassium dichromate, the EC50 after 24 hours was determined to be 1.90 (95% CI: 1.43-2.69) mg/L, indicating that the sensitivity of the daphnids was consistent with the level proposed by the OECD 202 guideline (EC50-24 h between 0.6 and 2.1 mg/L).

Biological results:

Immobilization rates after 24 and 48 hours of exposure:

Nominal loading level of the test item in the WAF [mg/L]	IMMOBILIZATION [%]
	24 hours					48 hours
	Replicates					Replicates
	1	2	3	4	MV	1	2	3	4	MV
8.00	80	40	80	80	70	100	100	100	100	100
3.64	20	0	0	0	5	20	0	20	20	15
1.65	0	0	0	20	5	0	0	0	20	5
0.751	0	20	20	0	10	0	20	20	0	10
0.342	0	0	0	0	0	0	0	0	20	5
Control	0	0	0	0	0	0	0	0	0	0

Absolute numbers of immobile Daphnids after 24 and 48 hours exposure:

Nominal loading level of the test item in the WAF [mg/L]	NUMBER OF IMMOBILE DAPHNIDS / TOTAL NUMBER OF DAPHNIDS
	24 hours					48 hours
	Replicates					Replicates
	1	2	3	4	Sum	1	2	3	4	Sum
8.00	4/5	2/5	4/5	4/5	14/20	5/5	5/5	5/5	5/5	20/20
3.64	1/5	0/5	0/5	0/5	1/20	1/5	0/5	1/5	1/5	3/20
1.65	0/5	0/5	0/5	1/5	1/20	0/5	0/5	0/5	1/5	1/20
0.751	0/5	1/5	1/5	0/5	2/20	0/5	1/5	1/5	0/5	2/20
0.342	0/5	0/5	0/5	0/5	0/20	0/5	0/5	0/5	1/5	1/20
Control	0/5	0/5	0/5	0/5	0/20	0/5	0/5	0/5	0/5	0/20

Analytical results:

Measured concentrations of the two main constituents and percent of the initial concentrations during the definitive test: 

Sampling date	Fresh media, 0 hours	Old media, 24 hours		Fresh media, 24 hours	Old media, 48 hours
Nominal loading level of the test item in the WAF [mg/L]	Meas.conc.[mg/L]	Meas.conc.[mg/L]	%	Meas.conc.[mg/L]	Meas.conc.[mg/L]	%
8.00	4.97	5.03	101	4.00	3.20	80
3.64	2.31	2.14	93	2.22	2.73	123
1.65	1.05	0.836	79	1.32	0.810	62
0.751	0.334	0.208	62	0.389	0.277	71
0.342	0.133	0.108	81	0.150	0.102	68
Control	<LOQ	<LOQ		<LOQ	<LOQ

Effect levels:

EL10-, EL50- (with 95% Confidence Limits), EL100-Values and NOEL:

Effect level	Test duration [hours]	Nominal loading of the test item [mg/L]
EL10 (with 95% confidence limits)	24	6.72	(Cl: Not applicable)
	48	3.38	(CI: < 0.342 - 7.96)
EL50 (with 95% confidence limits)	24	7.73	(CI: 1.77 - > 8.00)
	48	4.31	(CI: 1.86 - 7.98)
EL100	24	> 8.00
	48	8.00
NOEL	48	1.65

Validity criteria fulfilled:

yes

Conclusions:

Based on the nominal loadings of the test item, the 48 hour-EL50 for Daphnia magna was found to be 4.31 mg/L (95% confidence limits: 1.86 - 7.98 mg/L). The NOEL after 48 hours was 1.65 mg/L.

Executive summary:

The purpose of this study was to determine the influence of the test item on the mobility of Daphnia magna according to OECD 202 (2004). The study was performed under semi-static conditions (with a renewal of the test solutions after 24 hours) over a period of 48 hours. Five WAF's (Water Accommodated Fractions) of the test item prepared individually at loading levels in the range of 0.342 to 8.00 mg/L in a geometric series with a separation factor of 2.2. All WAFs were visually clear throughout the exposure period. The dispersions were shaken for 24h with 20 rpm at room temperature.

Twenty daphnids (divided into 4 replicates with 5 daphnids each) were exposed to each WAF and the control.

Specific chemical analysis was performed to demonstrate consistent preparation of the WAFs and stability during the test. The measured concentrations of the test item based on two main constituents in the old media (24 and 48 hours) were in the range of 62 to 123% of the initially measured concentrations. This means, that the test item was sufficiently stable during the exposure.

The validity criteria of the test guideline were fulfilled.

Based on the nominal loadings of the test item, the 48 hour-EL50 for Daphnia magna was 4.31 mg/L (95% confidence limits: 1.86 - 7.98 mg/L). The NOEL after 48 hours was 1.65 mg/L.

Description of key information

The acute toxicity of the test substance towards daphnia magna was tested in a GLP study according to OECD 202.

In the semi-static study in a closed system without headspace, the 48 hour-EL50 for Daphnia magna was determined to be 4.31 mg/L (nominal concentrations).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

4.31 mg/L

Additional information

The key study was performed under semi-static conditions (with a renewal of the test solutions after 24 hours) in a closed system without headspace over a period of 48 hours with five WAF (Water Accommodated Fractions) of the test item prepared individually at loading levels in the range of 0.342 to 8.00 mg/L in a geometric series with a separation factor of 2.2. Twenty daphnids (divided into 4 replicates with 5 daphnids each) were exposed to each WAF and the control. Based on the nominal loadings of the test item, the 48 hour-EL50 for Daphnia magna was 4.31 mg/L (95% confidence limits: 1.86 - 7.98 mg/L). The NOEL after 48 hours was 1.65 mg/L.