3-methyl-2-butenyl salicylate

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:

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

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

See read-across justification attached to section 13.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

2004

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

4.2 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: value recalculated based on molecular weight of source and target substance

Duration:

48 h

Dose descriptor:

EC10

Effect conc.:

2.9 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: value recalculated based on molecular weight of source and target substance

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

> 4.6 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: value recalculated based on molecular weight of source and target substance

Validity criteria fulfilled:

yes

Conclusions:

In the study the test item was found to affect the mobility of Daphnia magna after 48 hours with the following effect values (based on geometric mean measured test item concentrations): The EC50 and EC10-values were 4.2 mg/L and 2.9 mg/L, recalculated based on molecular weight of source and target substance.

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 2017-06-09 to 2017-06-15

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: 0.970 - 2.13 - 4.70 - 10.3 - 22.7 - 50.0% of the saturated solution
- Sampling method: 0h, 24h aged, 24h fresh, and 48h fresh.
- Sample storage conditions before analysis: All samples were stored at 6 ± 2°C until the start of the analysis.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Saturated solution: nominal concentration 30 mg/L, corresponding to 32.4 µL in 1.15 L. Prepared 4 days before start of experiment.
1) appropriate amount of the test item (32.4 μL/1.15 L demineralized water at pH 4) was placed onto the water surface and the bottle was closed with a screw cap.
2) slow stirring procedure was applied for 96 hours.
3) saturated solution was removed by siphoning from the approximate bottom of the glass flask.
4) Check for Tyndall effect and for undissolved test item (formation of an emulsion) (Result was negative)
5) mineral components of the dilution water were added to the saturated solution.
6) saturated solution was used as a stock solution for the preparation of six dilution levels by dilution with dilution water.
7) for the water renewal after 24 hours, the stirring period of the saturated solution was continued for a further 24 hours.
- Test concentration: 0.970 - 2.13 - 4.70 - 10.3 - 22.7 - 50.0% of the saturated solution
- Controls: Dilution water without test item incubated under the same conditions as the test groups.

Test organisms (species):

Daphnia magna

Details on test organisms:

- Test system: Daphnia magna STRAUS (Clone 5)
- Reason for the selection of the test system: Daphnia magna is the preferred species in accordance with the test guideline and is bred at the test facility.
- Culture: In glass vessels (2-3 L capacity) with approximately 1.8 L culture medium, at 20 ± 2 °C, in an incubator, 16 hours illumination, light intensity of max. 1500 lx
- Culture medium: Elendt M4, according to OECD 202, Annex 3 (2004), modified to a total hardness of 160 to 180 mg CaCO3/L.
- Culture feeding: at least 5 times per week ad libitum with a mix of unicellular green algae, e.g. Pseudokirchneriella subcapitata and Desmodesmus subspicatus, with an algae cell density of > 1E+06 cells/mL.
- Age of the daphnids at the start of the exposure: Less than 24 hours old
- Acclimatization: Acclimatization of the daphnids was not necessary, because 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:

Dilution water: 160 to 180 mg/L as CaCO3

Test temperature:

20.8 °C at test start, 19.8°C after 24h

pH:

At the start: 7.9-9.0
At the end: 8.0-8.6

Dissolved oxygen:

At the start: 8.13-8.50 mg/L
At the end: 7.44-8.80 mg/L

Conductivity:

Dilution water: 428-441 μS/cm

Nominal and measured concentrations:

Nominal: 0.970 - 2.13 - 4.70 - 10.3 - 22.7 - 50.0% of the saturated solution
Measured geometric mean: 0.102, 0.231, 0.502, 1.08, 2.50, 4.34 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass beakers (4 (ID) x 7 (H) cm), 50 mL capacity, loosely covered with watch glasses
- Test volume: 20 mL
- Renewal rate of test solution: after 24 hours
- 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 OECD 202
- Intervals of water quality measurement: Dilution water: 0 hours and 24 hours; Test media: 0 hours, 24 hours and 48 hours

OTHER TEST CONDITIONS
- Photoperiod: 16/8 hours light/dark cycle
- Light intensity: max. 1500 lx

EFFECT PARAMETERS MEASURED: Biological Parameters: Immobilization was determined in all groups after 24 and 48 hours. An animal was considered immobile, if it was not able to swim in the water phase within 15 seconds after gentle agitation of the test vessel.

RANGE-FINDING STUDY
- Test concentrations: 1, 10 and 100 mg/L
- Results used to determine the conditions for the definitive study: The saturated solution and the dilution levels 1 and 10% of the saturated solution were visually clear throughout the exposure period. No Tyndall effect was observed in the saturated solution. Immobilization rates were 0% and 45% for 1% and 10% of saturated solution after 48 hours. 100% mortality at 100% of saturated solution.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

3.96 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC10

Effect conc.:

2.74 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

> 4.34 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Observations: All tested concentration levels were visually clear throughout the exposure.
Analytical data: The measured concentrations of the test item in fresh media at the start of the exposure and at renewal (0 and 24 hours) reflect the dilution level of the saturated solution. 24 to 46% were recovered in old media at renewal and at the end of the test (24 and 48 hours). Since the measured test item concentrations were not within the range of ± 20% of the nominal concentrations, the geometric mean measured concentrations were calculated.
Water Quality Parameters: The measured water quality parameters (i.e. pH-value, dissolved oxygen concentration, total water hardness and water temperature) were within the acceptable limits.

Results with reference substance (positive control):

The percentage of immobility for the reference item potassium dichromate was determined after 24 hours.
EC50: 2.05 mg/L
95% confidence limits: 1.80 - 2.33 mg/L
The EC50 value of reference item potassium dichromate after 24 h is within the valid range of 0.6-2.1 mg/L according to OECD 202 (2004).

Results of non-GLP range finding test:

Saturated solution (%)	% immobilization
	24h	48h
100	100	100
10	35	0
1	0	0
Control	0	0

Immobilization Rates after 24 and 48 hours of Exposure:

Nominal test item concentration [% of saturated solution]	Geometric mean measured test item concentration [mg/L]	IMMOBILIZATION [%]
		24 hours Replicates					48 hours Replicates
		1	2	3	4	MV	1	2	3	4	MV
50.0	4.34	0	0	0	0	0	100	80	40	20	60
22.7	2.50	0	0	0	0	0	0	0	0	0	0
10.3	1.08	0	0	0	0	0	0	0	0	0	0
4.70	0.502	0	0	0	0	0	0	0	0	0	0
2.13	0.231	0	0	0	0	0	0	0	0	0	0
0.970	0.102	0	0	0	0	0	0	0	0	0	0
Control		0	0	0	0	0	0	0	0	0	0

Measured Concentrations (mg/L) of the test Item during the main test:

Saturated solution (%)	0h, fresh	24h, aged	24h, fresh	48h, aged	geometric mean
50	7.85	1.86	8.71	2.78	4.34
22.7	3.64	1.46	3.98	1.85	2.5
10.3	1.53	0.623	1.78	0.799	1.08
4.7	0.731	0.316	0.826	0.334	0.502
2.13	0.327	0.149	0.37	0.157	0.231
0.97	0.154	0.0636	0.167	0.0654	0.1
Control	< LOQ	< LOQ	< LOQ	< LOQ	/

Validity criteria fulfilled:

yes

Conclusions:

Based on the geometric mean measured concentrations of the test item, the 48 hour-EC50 for Daphnia magna was 3.96 mg/L and EC-10 was 2.74 mg/L.

Executive summary:

In the acute immobilization test with Daphnia magna (STRAUS), the effects of the test item were determined according to OECD 202 (2004). The study was conducted under semi-static conditions over a period of 48 hours with 6 concentrations of the test item in the range of 0.970 - 50.0% of the saturated solution, prepared in a geometric series with a separation factor of 2.2 and corresponding to geometric mean measured concentrations of 0.102 - 0.231 - 0.502 - 1.08 - 2.50 - 4.34 mg/L. All tested concentration levels were visually clear throughout the exposure.

The concentrations of the test item were analytically verified via HPLC- DAD in fresh media of all concentration levels and in the control at the start of the exposure and at renewal (0 and 24 hours) and in 24-hours old media at renewal and at the end of the test (24 and 48 hours).The measured concentrations of the test item in old media at renewal and at the end of the test (24 and 48 hours) were in the range of 24 to 46% of the initially measured. Since the measured test item concentrations were not within the range of ± 20% of the nominal concentrations, the effect concentrations are based on the geometric mean measured concentrations of the test item.

The validity criteria of the test guidelines were fulfilled.

Based on the geometric mean measured concentrations of the test item, the 48 hour-EC50 for Daphnia magna was 3.96 mg/L.

Description of key information

In a semi-static short term study the surrogate test item was found to affect the mobility of Daphnia magna after 48 hours with the following effect values (based on geometric mean measured test item concentrations): The EC50 and EC10-values were 4.2 mg/L and 2.9 mg/L, recalculated based on molecular weight of source and target substance.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

4.2 mg/L

Additional information

In the acute immobilization test with Daphnia magna (STRAUS), the effects of the surrogate test item were determined at the test facility according to OECD 202 (2004) in 2017. The study was conducted under semi-static conditions over a period of 48 hours with 6 concentrations of the surrogate test item in the range of 0.970 - 50.0% of the saturated solution, prepared in a geometric series with a separation factor of 2.2, corresponding to geometric mean measured concentrations of 0.102 - 0.231 - 0.502 - 1.08 - 2.50 - 4.34 mg/L. All tested concentration levels were visually clear throughout the exposure. Twenty daphnids (divided into 4 replicates with 5 daphnids each) were exposed to each concentration level and the control. The concentrations of the test item were analytically verified via HPLC- DAD in fresh media of all concentration levels and in the control at the start of the exposure and at renewal (0 and 24 hours) and in 24-hours old media at renewal and at the end of the test (24 and 48 hours). The measured concentrations of the surrogate test item in old media at renewal and at the end of the test (24 and 48 hours) were in the range of 24 to 46% of the initially measured. Since the measured concentrations were not within the range of ± 20% of the nominal concentrations, the effect concentrations are based on the geometric mean measured concentrations of the test item. The validity criteria of the test guidelines were fulfilled. The EC50 of the read across test item was determined to be 3.96 mg/L with a 95% confidence limit of 3.22 - > 4.34 mg/L. The EC10 was determined to be 2.74 mg/L with a 95% confidence limit of <2.50 - 3.37 mg/L. The EC 100 was determined to be >4.34.

The EC50 and EC10-values were 4.2 mg/L and 2.9 mg/L, recalculated based on molecular weight of source and target substance.