O-phosphoserine

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:

from 2017-08-21 to 2017-09-13

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)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1010 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

TOXI-COOP ZRT., 8230 Balatonfüred, Arácsi út 97., Hungary

Analytical monitoring:

yes

Details on sampling:

- Sampling method: 4 replicate samples of 5 mL were taken from the test solution (100 mg/L) and the control at the start and the end of the test. Formulation samples were diluted with Ultrapure Water and analysed after derivatization by an HPLC method with UV detection.
- Sample storage conditions before analysis: Samples were tested immediately after sampling.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- The test solution used in the test was prepared by mechanical dispersion without using of any solubilising agent. An amount of 0.03 g test item was dissolved in 300 mL dilution water (ISO Medium) to obtain the nominal concentration of 100 mg/L.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Strain/clone: Straus
- Source: Laboratory of Hydrobiology (Central Agricultural Office, Directorate of Plant-, and Soil Protection) 2100 Gödöllő, Kotlán S. u. 3., Hungary
- Feeding during test: no

ACCLIMATION
- Test animals were bred under similar conditions as that used during the exposure period, therefore additional acclimatisation before the test was not necessary.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

249 mg/L CaCO3

Test temperature:

19.6 - 20.2 °C

pH:

6.18 - 8.11

Dissolved oxygen:

7.49 - 8.21 mg/L

Salinity:

NA

Nominal and measured concentrations:

Nominal concentrations: 0 and 100 mg/L
Measured concentration: in the range of 100 - 105 % of the nominal concentration

Details on test conditions:

TEST SYSTEM
- Test vessel: glass beakers
- Fill volume: approximately 40 mL medium
- Aeration: no
- 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: ISO Medium, prepared according to OECD 202
- Culture medium different from test medium: Reconstituted water of a similar quality regarding to pH, components of the main ions and total hardness as the test water used in the test.


OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16-hour light, 8-hour dark cycle
- Light intensity: 638 lux

RANGE-FINDING STUDY
- Test concentrations: 0 and 100 mg/L
- Results used to determine the conditions for the definitive study: No immobility or any sub-lethal effects were detected.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Duration:

48 h

Dose descriptor:

EC10

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

There was no immobilisation observed in twenty daphnids exposed to either test item treated or control group. In addition to immobility, no abnormal behaviour or appearance of test animals was detected. Accordingly, the 48-h NOEC was determined to be 100 mg/L. The 48-h EC50 and LOEC were determined to be higher than 100 mg/L.

Results with reference substance (positive control):

The date of the last study with reference item Potassium dichromate was: 07 – 08 March 2017.
The 24h EC50: 1.41 mg/L, (95 % confidence limits: 1.19 – 1.68 mg/L)

Analytical Results

The measured concentration of O-Phospho-L-serine was 105 % of the nominal at the start and 100 % at the end of the test. The measured test item concentration remained within ± 20 % of the nominal during the test period of 48 hours, therefore, the biological results are based on the nominal concentration.

Table 1. Test item measured concentrations

Sampling date	Nominal concentration (mg Test Item/L)	Mean of the measured concentrations (mg Test Item/L)	Measured concentration in percentage of the nominal	Relative Standard Deviation % (n=4)
22 August 2017	100	105.4	105	1
24 August 2017	100	100.4	100	2

Table 2. Summary of biological endpoints

Endpoints	Concentration [mg/L] (endpoints are based on nominal concentration)
48 h-EC10	> 100
48 h-EC20	> 100
48 h-EC50	> 100
48 h-NOEC	100
48 h-LOEC	> 100

Validity criteria fulfilled:

yes

Conclusions:

In a short-term toxicity test with Daphnia magna, the test item showed no immobilisation or any other toxic effects up to the limit test concentration. Accordingly, the 48-h EC50 was determined to be >100 mg/L.

Executive summary:

In the acute immobilisation test with Daphnia magna (STRAUS), the effects of the test item were determined according to OECD 202, Regulation (EC) No. 440/2008 Method C.2 and EPA OPPTS 850.1010. The study was conducted in a static system over a period of 48 hours with a limit concentration of 100 mg/L. 20 daphnids per test concentration and control were tested. The test item concentration was determined at the start and at the end of the test with HPLC-UV and it was in the range of 100 - 105 % of the nominal concentration. Therefore, the biological endpoints were based on the nominal concentration. The validity criteria of the test guideline were fulfilled. There was no immobilisation observed in twenty daphnids exposed to each test item treated and control group. Further no abnormal behaviour or appearance of test animals was noted. The estimated EC50 value (48 hours) of the test item based on the nominal concentration is >100 mg/L.

Description of key information

In a short-term toxicity test with Daphnia magna, the test item showed no immobilisation or any other toxic effects up to the limit test concentration. Accordingly, the 48-h EC50 was determined to be >100 mg/L.

Additional information

In the acute immobilisation test with Daphnia magna (STRAUS), the effects of the test item were determined according to OECD 202, Regulation (EC) No. 440/2008 Method C.2 and EPA OPPTS 850.1010 (reference 6.1.3-1). The study was conducted in a static system over a period of 48 hours with a limit concentration of 100 mg/L. 20 daphnids per test concentration and control were tested. The test item concentration was determined at the start and at the end of the test with HPLC-UV and it was in the range of 100 - 105 % of the nominal concentration. Therefore, the biological endpoints were based on the nominal concentration. The validity criteria of the test guideline were fulfilled. There was no immobilisation observed in twenty daphnids exposed to each test item treated and control group. Further no abnormal behaviour or appearance of test animals was noted. The estimated EC50 value (48 hours) of the test item based on the nominal concentration is >100 mg/L.