Ethyltriphenylphosphonium acetate

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:

19 February 2018 - 10 April 2018

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 0 (control), 0.10, 0.32, 1.0, 3.2, 10 mg/
- Sample storage conditions before analysis: The samples were stored frozen prior to analysis.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
A nominal amount of test item (50 mg) was dissolved in test water and the volume adjusted to 500 mL to give a 100 mg/L stock solution from which a series of dilutions was made to give the required test concentrations of 0.10, 0.32, 1.0, 3.2 and 10 mg/L.
Each prepared concentration was inverted several times to ensure adequate mixing and homogeneity.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Strain/clone: clone 5, originally supplied by University of Sheffield/UK
- Source: in-house laboratory cultures
- Feeding during test: no

ACCLIMATION
- Acclimation conditions: Elendt M7 medium
- Type and amount of food: Each culture was fed daily with a mixture of algal suspension (Desmodesmus subspicatus) and Tetramin® flake food suspension.

METHOD FOR PREPARATION AND COLLECTION OF EARLY INSTARS OR OTHER LIFE STAGES:
Gravid adults were isolated the day before initiation of the test, such that the young daphnids produced overnight were less than 24 hours old. These young were removed from the cultures and used for testing. The diet and diluent water are considered not to contain any contaminant that would affect the integrity or outcome of the study.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test temperature:

20°C to 21°C

pH:

7.8 - 7.9 at test start, 8.0 at test end

Dissolved oxygen:

9.2 - 9.3 mg O2/L at test start, 8.4 - 8.7 mg O2/L at test end

Nominal and measured concentrations:

0 (control), 0.10, 0.32, 1.0, 3.2, 10 mg/L (nominal)

Details on test conditions:

TEST SYSTEM
- Test vessel: 150 mL beakers containing approximately 100 mL of test preparation
- Aeration: no
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 h light / 8 h darkness with 20 minute dawn and dusk transition periods
- Light intensity: between 200 and 1200 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
immobilization or adverse reactions to exposure were recorded at 24 and 48 hours after the start of exposure

RANGE-FINDING STUDY
- Test concentrations: Control, 0.1, 1.0, 10, 100 mg/L
- Results used to determine the conditions for the definitive study:
No immobilization was observed at the test concentration of 0.10 mg/L, however, 30% immobilization was observed at 1.0 mg/L and 100% immobilization was observed at 10 and 100 mg/L.
Based on this information test concentrations of 0.10, 0.32, 1.0, 3.2 and 10 mg/L were selected for the definitive test.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

1.8 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mortality

Remarks on result:

other: 95% Confidence Limits (mg/L)

Remarks:

1.0-3.2

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

2 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mortality

Remarks on result:

other: 95% Confidence limits (mg/L)

Remarks:

1.7 – 2.3

Details on results:

- Behavioural abnormalities: No sub lethal effects of exposure were observed throughout the test.
- Mortality of control: no
- Other adverse effects control: no
At the start and throughout the test all control and test solutions were observed to be clear colorless solutions.

Results with reference substance (positive control):

- Results with reference substance valid? yes
- Relevant effect levels:
24 h EC50 = 0.79 mg/L (95% c.i. 0.73 - 0.86 mg/L)
- The results of the inter laboratory tests and a Technical Corrigendum to ISO 6341 give a 24 Hour EC50 for potassium dichromate within the range 0.6 mg/L to 2.1 mg/L

Reported statistics and error estimates:

The EC50 values and associated confidence limits at 24 and 48 hours and the slope of the response curve and its standard error were calculated by the Trimmed Spearman Karber method. The LOEC and the NOEC at 24 and 48 hours were calculated using the Fisher’s Exact Binomial Test with Bonferroni correction. All results were calculated using the ToxRat Professional computer software package (TOXRAT).

Validity Criteria

The test was considered to be valid given that none of the control daphnids showed immobilization or other signs of disease or stress and that the oxygen concentration at the end of the test was equal to or greater than 3 mg/L in the control and test vessels.

Cumulative Immobilization Data and Observations in the Range‑finding Test

Nominal Concentration (mg/L)	Observations (Initial Population: 5 Per Replicate)
	24 Hours				48 Hours
	Cumulative Immobilized Daphnia		Observations		Cumulative Immobilized Daphnia		Observations
	Rep1	Rep2	Rep1	Rep2	Rep1	Rep2	Rep1	Rep2
Control	0	0	5 N	5 N	0	0	5 N	5 N
0.10	0	0	5 N	5 N	0	0	5 N	5 N
1.0	0	0	5 N	5 N	1	2	4 N	3 N
10	5	5	AI	AI	5	5	AI	AI
100	5	5	AI	AI	5	5	AI	AI

 

Cumulative Immobilization Data and Observations in the Definitive Test

Nominal Concentration (mg/L)	24 Hours
	Cumulative Immobilized Daphnia (Initial Population: 5 Per Replicate)						Observations
	Rep1	Rep2	Rep3	Rep4	Total	%	Rep1	Rep2	Rep3	Rep4
Control	0	0	0	0	0	0	5 N	5 N	5 N	5 N
0.10	0	0	0	0	0	0	5 N	5 N	5 N	5 N
0.32	0	0	0	0	0	0	5 N	5 N	5 N	5 N
1.0	0	0	0	0	0	0	5 N	5 N	5 N	5 N
3.2	5	5	3	5	18	90	A	AI	2 N	AI
10	5	5	5	5	20	100	AI	AI	AI	AI
Nominal Concentration (mg/L)	48 Hours
	Cumulative Immobilized Daphnia (Initial Population: 5 Per Replicate)						Observations
	Rep1	Rep2	Rep3	Rep4	Total	%	Rep1	Rep2	Rep3	Rep4
Control	0	0	0	0	0	0	5 N	5 N	5 N	5 N
0.10	0	0	0	0	0	0	5 N	5 N	5 N	5 N
0.32	0	0	0	0	0	0	5 N	5 N	5 N	5 N
1.0	0	0	0	0	0	0	5 N	5 N	5 N	5 N
3.2	5	5	5	5	20	100	AI	AI	AI	AI
10	5	5	5	5	20	100	AI	AI	AI	AI

Validity criteria fulfilled:

yes

Conclusions:

The 48 h EC50 of ETPPAAc to Daphnia magna was 1.8 mg/L (95 % cl 1.0 – 3.2 mg/L).

Executive summary:

This study was performed to assess the acute toxicity of ETPPAAc to Daphnia magna. The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (April 2004) No 202, "Daphniasp., Acute Immobilisation Test" referenced as Method C.2 of Commission Regulation (EC) No. 440/2008.

Following a preliminary range‑finding test and initial experiment, 20 daphnids (4 replicates of 5 animals) were exposed to an aqueous solution of the test item at nominal concentrations of 0.10, 0.32, 1.0, 3.2 and 10 mg/L for 48 hours at a temperature of 20 °C to 21 °C under static test conditions. The number of immobilized daphnids were recorded after 24 and 48 hours.

Analysis of the test preparations at 0 and 48 hours showed measured test concentrations to be near nominal with the exception of the 10 mg/L test concentration. This was near nominal at 0-Hours but had declined to 75% of nominal at 48-Hours. Considering that the EC50 falls between 1.0 and 3.2 mg/L and these were near nominal, the results are based on nominal test concentrations.

Exposure of Daphnia magna to the test item gave the following results: 48 h EC50 = 1.8 mg/L (95 % cl 1.0 – 3.2 mg/L).

Description of key information

48 h EC50 = 1.8 mg/L (95 % cl 1.0 – 3.2 mg/L) (OECD TG 202, Daphnia magna, static)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

1.8 mg/L

Additional information

This study was performed to assess the acute toxicity of ETPPAAc to Daphnia magna. The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (April 2004) No 202, "Daphniasp., Acute Immobilisation Test" referenced as Method C.2 of Commission Regulation (EC) No. 440/2008.

Following a preliminary range‑finding test and initial experiment, 20 daphnids (4 replicates of 5 animals) were exposed to an aqueous solution of the test item at nominal concentrations of 0.10, 0.32, 1.0, 3.2 and 10 mg/L for 48 hours at a temperature of 20 °C to 21 °C under static test conditions. The number of immobilized daphnids were recorded after 24 and 48 hours.

Analysis of the test preparations at 0 and 48 hours showed measured test concentrations to be near nominal with the exception of the 10 mg/L test concentration. This was near nominal at 0-Hours but had declined to 75% of nominal at 48-Hours. Considering that the EC50 falls between 1.0 and 3.2 mg/L and these were near nominal, the results are based on nominal test concentrations.

Exposure of Daphnia magna to the test item gave the following results: 48 h EC50 = 1.8 mg/L (95 % cl 1.0 – 3.2 mg/L).