3-(p-methoxyphenyl)-2-methylpropionaldehyde

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:

20 Mar 2016 to 9 May 2016

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:

April, 2004

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

May, 2008

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Samples for possible analysis were taken from all test concentrations and the control at the test start and after 48 hours. Samples were taken from one replicate of each test concentration. Additionally, reserve samples of 3.0 mL were taken for possible analysis. During sampling, 3.0 mL medium was taken from the approximate centre of the test vessels. Samples were stored in a freezer until analysis.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
The test item was completely soluble in test medium at the concentrations tested. No correction was made for the purity/composition of the test item. Weighing of test item and preparation of test solutions was performed under dimmed light. Preparation of test solutions started with a nominal concentration of 100 mg/L applying one day of magnetic stirring in a closed vessel to accelerate the dissolving of the test item in the test medium. The lower test concentrations were prepared by subsequent dilutions of the 100 mg/L concentration in test medium. The final test solutions were all clear and colourless.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Strain/clone: Straus, 1820
- Generation: at least third generation, obtained by acyclical parthenogenesis under specified breeding conditions.
- Source: In-house laboratory culture with a known history.
- Validity of batch: Daphnids originated from a healthy stock, 2nd to 5th brood, showing no signs of stress such as mortality >20%, presence of males, ephippia or discoloured animals and there was no delay in the production of the first brood.
- Characteristics: For the test selection of young daphnids with an age of < 24 hours, from parental daphnids of more than two weeks old.
- Feeding during test: No

BREEDING
- Start of each batch: With newborn daphnids, i.e. less than 3 days old, by placing about 250 of them into 5 litres of medium in an all-glass culture vessel.
- Maximum age of the cultures: 4 weeks
- Renewal of the cultures: After 7 days of cultivation half of the medium twice a week.
- Temperature of medium: 18 - 22°C
- Feeding: Daily, a suspension of fresh water algae.
- Medium: M7, as prescribed by Dr. Elendt-Schneider (Elendt, B.-P., 1990: Selenium deficiency in Crustacea. An ultrastructural approach to antennal damage in Daphnia magna Straus. Protoplasma 154, 25-33).

ACCLIMATION
- Acclimation period: none

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

180 mg/L (as CaCO3)

Test temperature:

20 °C

pH:

- Start: 7.9
- End: 7.8 - 8.1

Dissolved oxygen:

- Start: 8.5 - 8.7 mg/L
- End: 8.6 - 8.8 mg/L

Nominal and measured concentrations:

- Nominal concentrations: 0 (control), 10, 18, 32, 56 and 100 mg/L (based on range-finding test)
- Measured concentrations (start, t = 0h): 0 (control), 8.87, 15.8, 28.8, 51.9 and 97.5 mg/L
- Measured concentrations (end, t = 48h): 0 (control), 9.03, 15.9, 28.9, 52.3 and 96.0 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 60 mL, airtight closed with no headspace to prevent any loss of the test item due to volatilization.
- Type:closed
- Headspace, fill volume: no headspace, fill volume 60 mL
- Aeration: No
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- Biomass loading rate: 5 per vessel containing 60 mL of test solution
- Introduction of test organisms: Immediately after preparation of the test solutions.

TEST MEDIUM / WATER PARAMETERS
- Test medium: Adjusted ISO medium (Elendt M7)
- Culture medium different from test medium: same
- Intervals of water quality measurement: pH was measured at the beginning and at the end of the test, for all concentrations and the control; Dissolved oxygen was measured at the beginning and at the end of the test, for all concentrations and the control. In addition after 24 hours, immediately after counting the immobilized daphnids, oxygen levels were measured in one replicate of the solution of lowest concentration at which all the Daphnia magna were immobilized; Temperature of medium was measured continuously in a temperature control vessel, beginning at the start of the test.

OTHER TEST CONDITIONS
- Light: no light

EFFECT PARAMETERS MEASURED:
- Immobility: Immobility (including mortality) was recorded at 24 hours and at 48 hours. Immobile are those animals not able to swim within 15 seconds after gentle agitation of the test vessel. and abnormal behaviour

RANGE-FINDING STUDY
- Test concentrations: 0 (control), 0.10, 1.0, 10 and 100 mg/L
- Results used to determine the conditions for the definitive study: After 24 hours of exposure all daphnids exposed to the highest test concentration were immobilized. No (significant) immobility was observed at any of the lower test concentrations and the control during the test period. Note that a maximum of 10% immobile daphnids is acceptable for the control and therefore test concentrations with a maximum of 10% immobility are not considered significant. The expected EC50 was between nominal concentrations of 10 and 100 mg/L. Samples taken from nominally 10 and 100 mg/L were analysed. The analytical results showed that at a nominal concentration of 100 mg/L the initial concentration was in agreement with nominal (87%). This concentration remained stable during the 48-hour test period (98% of initial at the end of the test). At a nominal concentration of 10 mg/L the initial concentration was slightly below nominal (71%) but remained stable during the 48-hour test period (93% of initial at the end of the test). These results confirmed that the test substance was stable and that a static exposure regime was appropriate for the final test.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

12 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% C.I.: 8.8 - 14 mg/L

Remarks:

Measured concentrations remained within 20% of nominal; static test

Details on results:

After 24 hours of exposure, immobilisation was observed from the test concentration of 18 mg/L and increased in a dose-dependent manner up to 100% immobility at the two highest concentrations. After 48 hours of exposure, 25% immobilisation was observed in the lowest test concentration (10 mg/L) and 100% immobility at the four highest concentrations. No immobilisation was observed in the control. See 'Any other information on results incl. tables'.

Results with reference substance (positive control):

The most recent test conducted between 11 April 2016 and 13 April 2016, determined a 48h-EC50 of 0.29 mg/L. The sensitivity of this batch of Daphnia magna was slightly above the sensitivity of batches previously tested at WIL Research Europe (expected range 48h-EC50: 0.3 to 1.0 mg/L). This means that the daphnids used for the current study may have been slightly more sensitive to test items than usual, leading to a worst-case scenario.

Reported statistics and error estimates:

The 24 and 48h-EC50-value was calculated from the weibits of the percentages of affected daphnids and the logarithms of the corresponding test item concentrations using the maximum likelihood estimation method. ToxRat Professional v 3.2.1 (ToxRat Solutions® GmbH, Germany) was used to perform the analyses.

Table: Number of introduced daphnids and incidence of immobility in the final test

Time (h)	Replicate	Nominal concentration test substance (mg/L)
		Control	10	18	32	56	100
0	A	5	5	5	5	5	5
	B	5	5	5	5	5	5
	C	5	5	5	5	5	5
	D	5	5	5	5	5	5
Total introduced		20	20	20	20	20	20
24	A	0	0	3	3	5	5
	B	0	0	3	2	5	5
	C	0	0	1	4	5	5
	D	0	0	1	4	5	5
Total immobilised		0	0	8	13	20	20
Effect %		0	0	40	65	100	100
48	A	0	4	5[2]	5	5	5
	B	0	0	5	5	5	5
	C	0	0	5	5	5	5
	D	0	1	5	5	5	5
Total immobilised		0	5	20	20	20	20
Effect %		0	25	100	100	100	100

[ ]: number of daphnids observed trapped at the surface of the test solutions. These organisms were reimmersed into the respective solutions before recording of mobility.

Validity criteria fulfilled:

yes

Remarks:

see 'Any other information on materials and methods incl. tables'

Conclusions:

The 48-h EC50 value is 12 mg/L in aquatic invertebrates (Daphnia magna).

Executive summary:

The acute toxicity to aquatic invertebrates was determined in a study according to OECD TG 202 and in compliance with GLP criteria. In this study daphnids (D. magna, 20 per concentration) were exposed to nominal concentrations of 0 (control), 10, 18, 32, 56 and 100 mg/L for 48 hours under static conditions.Analytical confirmation of nominal test concentrations showed that all test concentrations remained well within ±20% of nominal concentrations throughout the test. Therefore, effect concentrations are expressed as nominal. Immobilization was recorded after 24 and 48 hours exposure. After 48 hours of exposure, no immobilization was observed in the control, 25% at 10 mg/L and 100% at the four highest test concentrations. Based on these data, the 48-h EC50 value is determined at 12 mg/L (95% C.I.: 8.8 – 14 mg/L).

Description of key information

The acute toxicity to aquatic invertebrates was determined in a study according to OECD TG 202 and in compliance with GLP criteria. In this study daphnids (D. magna, 20 per concentration) were exposed to nominal concentrations of 0 (control), 10, 18, 32, 56 and 100 mg/L for 48 hours under static conditions.Analytical confirmation of nominal test concentrations showed that all test concentrations remained well within ±20% of nominal concentrations throughout the test. Therefore, effect concentrations are expressed as nominal. Immobilization was recorded after 24 and 48 hours exposure.After 48 hours of exposure, no immobilization was observed in the control, 25% at 10 mg/L and 100% at the four highest test concentrations. Based on these data, the 48-h EC50 value is determined at 12 mg/L (95% C.I.: 8.8 – 14 mg/L).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

12 mg/L