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

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

31 Jul - 09 Sep 2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

Version / remarks:

2012

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: control and 10 mg/L
- Sampling method: 5 mL water samples were taken from all test solutions at the beginning (0 d), immediately prior to the first renewal of the test solution (3 d) and weekly thereafter (9, 21 d).

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A stock solution was prepared with a concentration of 1000 mg/L by dissolving 0.1025 g test substance in 100 mL deionized water (the concentration was adjusted by the purity of 97.6%). Test solution was prepared by dilution of the stock solution with Elendt M7 medium. For the limit concentration of 10 mg/L 0.5 mL of the stock solution was diluted to a total volume of 50 mL with M7 medium.
- Controls: M7 medium was used as negative control

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Age at study initiation (mean and range, SD): < 24 h
- Source: all organisms originated from cultures established from the same healthy stock of daphnia
- Feeding during test : yes
- Food type: concentrated solutions of Chlorella vulgaris
- Amount: 0.1 - 0.2 mg/C/Daphnia per day
- Frequency: once per day

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

21 d

Hardness:

221 - 232 mg CaCO3/L

Test temperature:

20 - 21 °C

pH:

7.4 - 7.8

Dissolved oxygen:

90 - 101% of the air saturation value

Nominal and measured concentrations:

- Nominal concentrations: control, 10 mg/L
- Measured concentrations control: see results

Details on test conditions:

TEST SYSTEM
- Test vessel: glass beaker
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: 50 mL
- Aeration: none
- Renewal rate of test solution (frequency/flow rate): test solutions were renewed every 72 hours
- No. of organisms per vessel: 1
- No. of vessels per concentration (replicates): 10
- No. of vessels per control (replicates): 10
- Biomass loading rate: 50 mL of test solution/daphnid

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Elendt M7 medium was used as dilution medium
- Culture medium different from test medium: no

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 hours light, 8 hours darkness
- Light intensity: 1000 - 1500 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : number of living offspring was counted for each vessel daily. Offspring produced was removed and counted daily from the appearance of the first brood to prevent them consuming food intended for adults. Test concentrations were analysed at the beginning (0 d), immediately prior to the first renewal of the test solution (3 d) and weekly thereafter (9, 21 d). Determination of test substance concentrations prior to renewal was performed on one seperate vessel at each test concentration. Oxygen concentration, pH, hardness, and temperature were measured once a week in the control and test concentrations. Observations were made on time to production of first brood and number of broods per surviving parental daphnia.

TEST CONCENTRATIONS
- Range finding study: yes
- Test concentrations: control, 1.0, and 10 mg/L
- Results used to determine the conditions for the definitive study: no dead daphnia at any tested concentration

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

>= 10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks on result:

other: and adult survival

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

> 10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks on result:

other: and adult survival

Reported statistics and error estimates:

For the estimation of the lowest observed effect concentration (LOEC), and the no observed effect concentration (NOEC), for the effects of the target substance on growth rate, the mean growth rate for each concentration were compared with the control mean using a multiple comparison method of independent samples t-test.

Table 1. Measured concentrations of Fosetyl-Na in test medium

Nominal concentration (mg/L)	Analyzed concentration (mg/L)						Mean analyzed concentration (mg/L)
	Day 0	Day 3		Day 9		Day 21
	fresh	aged	fresh	aged	fresh	aged
Control	< LOD	< LOD	< LOD	< LOD	< LOD	< LOD	-
10.0	9.29	9.17	9.14	9.01	9.27	9.25	9.19

 

 

Table 2. Summary of offspring data in a 21 day reproduction test with daphnia magna

Replicate	Offspring number		Number of dead adults
	Control	10.0 mg/L	Control	10.0 mg/L
1	61	58	0	0
2	74	64	0	0
3	62	58	0	0
4	64	65	0	0
5	59	55	0	0
6	63	62	0	0
7	61	60	0	0
8	64	68	0	0
9	63	41	0	0
10	61	68	0	0

 

 

 Table 3. Summary of fecundity

Nominal concentration in mg/L	Initial number of adults	21 d
		Mean Fecundity (No. live offspring per adult)	Inhibition rate (%)
Control	10	63	-
10.0	10	60	5.59

 

Table 4. Validity criteria OECD 211

Criterion from the guideline	Outcome	Validity criterion fulfilled
The mortality of parent animals in the control should not exceed 20% at the end of the test.	Mortality was 0%	Yes
The mean number of living offspring produced per parent animal in the control surviving at the end of the test should be ≥ 60.	61 - 74 animals	Yes

 

 

Validity criteria fulfilled:

yes

Remarks:

see Table 4 in 'any other information on results incl. tables'

Description of key information

NOEC (21 d, immobilisation and reproduction) ≥ 10 mg/L (nominal) for Daphnia magna (OECD 211)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

NOEC

Effect concentration:

>= 10 mg/L

Additional information

A GLP study on the long-term toxicity to aquatic invertebrates is available for Fosetyl-sodium. The study was conducted according to OECD guideline 211 on the chronic toxicity of Fosetyl-Sodium to Daphnia magna was under semi-static conditions. Daphnia were exposed to the nominal limit concentration of 10 mg/L and an untreated control at 20 - 21 °C for 21 days. The test item was dissolved in test water. No additional solvent was used. The test water was not aerated during the time of testing.

Analysis of 5 mL water samples taken from all test solutions at the beginning (0 d), immediately prior to the first renewal of the test solution (3 d) and weekly thereafter (9, 21 d) showed that the measured concentrations were within +/- 20% of nominal concentrations. Therefore, the results were based on nominal concentrations. No mortality or abnormal behaviour was observed in any treatment at the end of the study and the mean living offspring number per adult daphnid was 63 for the control and 60 in the limit concentration (10 mg/L). Thus, the study is valid according to OECD guideline 211 and the 21-day NOEC for reproduction and survival in Daphina magna is ≥ 10 mg/L (nominal).