Phosphonic acid, monoethyl ester, sodium salt (1:1)

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:

29 - 31 May 2001

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)

Qualifier:

according to guideline

Guideline:

EPA OPP 72-2 (Aquatic Invertebrate Acute Toxicity Test)

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Qualifier:

according to guideline

Guideline:

other: Methods for Acute Toxicity Tests with Fish, Macroinvertebrates, and Amphibians (EPA-660/3-75-009)

GLP compliance:

yes (incl. QA statement)

Remarks:

Hessisches Ministerium für Umwelt, Energie, Jugend, Familie und Gesundheit

Analytical monitoring:

yes

Details on sampling:

Chemical analysis of the freshly prepared and aged (48h) test solutions was performed for all tested concentrations.

Vehicle:

no

Details on test solutions:

Calculations of the aqueous concentrations of test substance were based on 100% purity of the test material. The test item was weighted out to a precision of 0.01 mg and dissolved in dilution water as a stock solution. Defined amounts of stock solution were given into the filled jars. The following amounts of test water were prepared: for the untreated control 1000 mL, for all treatment levels 500 mL. Two times 200 mL were used for the testing of biological effects. The residual amounts were used for the test item analysis or discarded.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Waterflea
- Strain: Clone 5
- Source: in-house laboratory culture
- Method of breeding: The daphnids used in this test were bred in the animal maintenance room of the Ökotoxikologie of Aventis CropScience GmbH. They were cultured in beakers containing initially 30 adult animals in 2 litre dilution water. Approximately twice a month the daphnids were transferred into freshwater resulting in the initial biological loading. The Daphnia cultures were maintained at 20 ± 2° Celsius and a photoperiod of 16 hours light, 8 hours dark. All cultures were fed with unicellular green algae. Algal cells, grown in nutrient medium, were concentrated by filtration and then re-suspended in a small volume of dilution water prior to feeding to the daphnids. Water used for breeding was the same as used in the test.
- Feeding during test: none

ACCLIMATION
- Acclimation period: The gravid mother animals were separated from the culture by sieves and means of a glass tube and then transferred into a 2 L crystallising dish, filled with dilution water. After a maximum of 24 hours the new-born daphnids were sampled at random with a glass tube. During adaptation the freshly prepared dilution water was maintained at 20 ± 1° Celsius.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

1.66 total hardness in mmol/L (Ca2+, Mg2+)

Test temperature:

19.1 - 19.9 °C

pH:

7.8

Dissolved oxygen:

9.0 - 9.2 mg O2/L

Nominal and measured concentrations:

control, 12.2, 21.9, 38.9, 68.1 and 121.6 mg/L (active ingredient: AE C529354, nominal)

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): covered with glass lids
- Material, size, headspace, fill volume: 300 mL glass jars, containing 200 mL test solution. The jars had a diameter of 90 mm and a height of 50 mm (approximate values of the internal dimensions). The depth of test water lay by 30 mm at the start and at the end of testing.
- Aeration: none
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Deionized water used as a basis in all toxicity tests at the Ökotoxikologie is obtained from a special water supply inside the factory and can be drawn from tap. This water is additionally filtered by a deionization unit and a charcoal filter within the laboratory before use. Dilution water was an artificial mineral medium M4 (Elendt, 1990), modified. To prevent precipitation during the preparation of the medium, the chemicals were added into 500 - 800 mL deionized water and then filled up to 1000mL.
- Conductivity: 472 - 602 µS/cm

OTHER TEST CONDITIONS
- Photoperiod: 16 h light, 8 h dark
- Light intensity: wide spectrum fluorescent lights

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Test jars were observed every 24 hours for immobile daphnids.

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 121.6 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mobility

Remarks on result:

other: equivalent to EC50 >550 mg AEC529354 technical concentrate 22.1%/L

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

121.6 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mobility

Remarks on result:

other: equivalent to NOEC = 550 mg AEC529354 technical concentrate 22.1%/L

Details on results:

No immobilisation and intoxication symptoms of the test animals were observed in any treatment levels and the untreated control.

The daphnids were added to the test vessels 50 minutes after the test substance was added to the test solution.

Table 1: Number of immobile daphnids

Test jar number	Concentration (mg/L)	Number of immobile daphnids
		24 h	48 h
1 + 2	Control	0/20	0/20
3 + 4	12.2	0/20	0/20
5 + 6	21.9	0/20	0/20
7 + 8	38.9	0/20	0/20
9 + 10	68.1	0/20	0/20
11 + 12	121.6	0/20	0/20

 

 

Table 2: Validity criteria OECD 202

Criterion from the guideline	Outcome	Validity criterion fulfilled
In the control, including the control containing the solubilising agent, not more than 10% of the daphnids should have been immobilized.	0% of control daphnids were immobilized throughout the test	Yes
The dissolved oxygen concentration at the end of the test should be ≥ 3 mg/L in control and test vessels.	The dissolved oxygen concentration in all vessels was 9.0 mg/L at the end of the test	Yes

Validity criteria fulfilled:

yes

Remarks:

see Table 2 in 'any other information on results incl. tables'

Description of key information

EC50 (48 h) > 121.6 mg a.i. (Fosetyl-Sodium)/L for Daphnia magna (OECD 202) (equivalent to > 550 mg Fosetyl-Sodium technical concentrate 22.1%/L) 

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

> 121.6 mg/L

Additional information

A GLP study according to OECD guideline 202 on the acute toxicity to the waterflea (Daphnia magna) was performed with Fosetyl-sodium (technical concentrate; 22.1 %; code: AE C529354 00 TK22 A101; containing 22.1% w/w Fosetyl-Sodium) under static conditions.

The test solutions were prepared as 12.2, 21.9, 38.9, 68.1 and 121.6 mg Fosetyl-Sodium/L additionally with an untreated control. The low purity (22.1 % w/w) of the technical concentrate was taken into consideration. The test item was dissolved in test water. No additional solvent was used. For all concentrations and the control groups a total of 20 daphnids in 2 two replicates of 10 animals were tested. During the whole test period the water was not aerated and the daphnids were not fed. Test temperature was kept at 20 ± 1 °C. Test duration was 48 hours.

Chemical analysis of the freshly prepared and aged (48 h) test solutions was performed for all tested concentrations for the test item using High Performance Liquid Chromatography with ultraviolet detection (HPLC/UV). The concentrations were diluted prior analyses.

Analyses of freshly prepared water for the test item resulted in concentrations ranging from 85.2% to 93.3% of nominal values. Analyses of aged water (48 h) at experimental termination resulted in test item concentrations ranging from 84.1% to 102.6% of nominal values. The mean measured values over the time of exposure ranged from 84.7% to 97.9%. Since mean measured values of Fosetyl-Sodium were within ± 20% of nominal at the start and the end of the study, all effect concentrations were based on nominal initial test concentrations.

The concentration estimated to immobilize 50% of the test animals (EC50) after 24 h and 48 h was >121.6 mg Fosetyl-Sodium/L (equivalent to >550 mg technical concentrate 22.1% / L). No immobilization and intoxication symptoms of the test animals were observed in any treatment levels and the untreated control.

The concentration without any observed effects (NOEC) after 24 and 48 hours test duration was 121.6 mg Fosetyl-Sodium/L.