5-oxo-DL-proline

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:

22 March 2017 to 24 March 2017

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:

2004

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

Qualifier:

according to guideline

Guideline:

other: JMAFF 2-7-2-1 The guidelines related to the study reports for the registration application of pesticide (Ref. No. 12-Nousan-8147 on 24 November 2000) & Ref. No.13-Seisan-3986 on 10 October 2001

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: Law Concerning the Evaluation of Chemical Substances and Regulation of their Manufacture, etc (Chemical Substance Control Law)

Version / remarks:

amended 2009 under the reference of YAKUSHOKHATSU No. 1121002, SEIKYOKU No.2 and KANPOKIHATSU No. 021121002

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Controlled room temperature (15 to 25 °C, below 70 % RH)

Analytical monitoring:

yes

Details on sampling:

- Analytical measurements were performed at the applied test concentration level at the beginning and at the end of the experiment.
- Sampling method: Samples were taken from the test solution and one sample from the control solution.

Vehicle:

yes

Remarks:

ISO Medium

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A stock solution with a concentration of 100 mg/L (nominal) was prepared with direct addition of the test material, mixed into the test medium (ISO Medium) using ultrasonic bath for 5 minutes. As a limit test was carried out, further dilution of stock solution was not performed.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Source: Bred in house
- Common name: Water flea
- Age of parental stock: They were less than 24 hours old at the beginning of the test.
- Feeding during test: No

ACCLIMATION
- Acclimation period: There was no acclimatization because the water used was similar to the culture water.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

247 mg/L as CaCO3

Test temperature:

20.7 to 20.8 °C

pH:

5.70 to 7.79

Dissolved oxygen:

8.4 to 9.0 mg/L

Nominal and measured concentrations:

Preliminary range finding test nominal concentrations: 0.1, 1, 10, 100 mg/L
Definitive test nominal concentration: 100 mg/L, measured concentration: 107 mg/L (at the start of the test) and 111 mg/L (at the end of the test)
As the measured concentrations deviated not more than 20 per cent from the nominal, the biological results are based on the nominal concentration.

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass beaker
- Type: Open
- Fill volume: At least 5 mL of solution per animal.
- No. of organisms per vessel: 5
- No. of vessels per concentration: 4
- No. of vessels per vehicle control: 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Reconstituted water (ISO medium, according to OECD 202) was used as dilution water for both the range finding and definitive tests. The same composition of reconstituted water was used for the tests and for breeding the test animals.
- Composition of ISO medium: CaCl2x2H2O: 11.76 g/L 25 ml/L, MgSO4x7H2O: 4.93 g/L 25 ml/L, KCl: 0.23 g/L 25 ml/L and NaHCO3: 2.59 g/L 25 ml/L.
- Intervals of water quality measurement: The water temperature was measured daily; the oxygen concentrations and pH of the controls and the test solution were measured at the beginning and at the end of the experiment.

OTHER TEST CONDITIONS
- Adjustment of pH: The pH of the test solution was not adjusted and not varied by more than 1.5 units in any one test.
- Photoperiod: The test was carried out in 16-hour light and 8-hour dark cycle

EFFECT PARAMETERS MEASURED: The immobility or mortality of the Daphnia was determined by visual observation 24 and 48 hours after the start of the test. Those animals not able to swim within 15 seconds after gentle agitation of the test beaker are considered to be immobile. The number of immobilised animals and the percentage of immobility were determined at 24 and 48 hours.

VEHICLE CONTROL PERFORMED: Yes, the dilution water (ISO-medium) was used without addition of the test material.

RANGE-FINDING STUDY
- A concentration range-finding test was conducted to determine the approximate toxicity of the test material so that appropriate test concentrations could be selected for use in the definitive test. Ten daphnids (divided into two replicates) in each test concentration and control were exposed for 48 hours under semi-static conditions (in absence of stability data).
During the formulation procedure the stock solution was prepared by the similar method described for the main study. The test solutions were prepared by appropriate dilution of the stock solution.
- Results used to determine the conditions for the definitive study: Because toxic response was not observed during the preliminary concentration range-finding test, a Limit Test was carried out using only one test concentration (100 mg/L) and one control group in a static system.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

IMMOBILISATION
The number of immobilised animals and the percentage of immobility were determined at the 24 th and 48 th hour. These results can be seen in Table 1. Although 5 % immobilisation could be observed at the test material group, statistical analysis was not performed since this difference is negligible due to that the accepted control immobilisation is 10 %.
In addition to immobility, no abnormal behaviour or appearance of test animals was detected.

Results with reference substance (positive control):

The date of the last study with reference item Potassium dichromate is: 08 - 09 March 2017.
The 24h EC50: 0.64 mg/L, (95 % confidence limits: 0.59 – 0.68 mg/L)

Reported statistics and error estimates:

No statistical analysis was performed because of the lack of toxic effects. The EC50, NOEC, LOEC and EC100 values were determined directly from the raw
data.

Validity

There was no immobilisation in the control group and the dissolved oxygen concentration at the end of the test in control and test vessels was more than 3 mg/L.

All validity criteria were within acceptable limits and therefore the study can be considered as valid.

Table 1: Number and percentage of immobilised animals

Test group	Number of treated animals	Number of immobilised animals
		24 hours		48 hours
		Number	Percent	Number	Percent
Control	20	0	0	0	0
100 mg/L	20	0	0	1	5

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of the study the following endpoints were reached:
24h and 48h EC50 value: > 100 mg/L (nominal)
48h EC100 value: > 100 mg/L (nominal)
48h No-Observed Effect Concentration (NOEC): 100 mg/L (nominal)
48h Lowest Observed Effect Concentration (LOEC): > 100 mg/L (nominal).

Executive summary:

The acute toxicity of the test material to Daphnia magna was determined in accordance with the standardised guidelines OECD 202, EU Method C.2, EPA OCSPP 850.1010, JMAFF 2-7-2-1 and The Guidelines for studies on the new chemical substance as required by the Law Concerning the Evaluation of Chemical Substances and Regulation of their Manufacture. The study was performed under GLP conditions.

Because no toxic response was observed during the preliminary range-finding test, a Limit Test was carried out using only one test concentration (100 mg/L) and one control group in the definitive test.

The test concentration was analytically determined at the start and at the end of the experiment using the HPLC-UV method. The measured concentration was 107 mg/L at the start and 111 mg/L at the end of the test.

As the measured concentrations deviated not more than 20 per cent from the nominal in all cases, biological results are based on the nominal concentration.

Twenty animals, divided into four groups (glass beaker) of five animals each were used at the test concentration and for the control. The test material was formulated directly in ISO Test Medium.

All validity criteria were met during this study.

Although 5 % immobilisation could be observed at the test material group, statistical analysis was not performed since this difference is negligible due to that the accepted control immobilisation is 10 %. In addition to immobility, no abnormal behaviour or appearance of test animals was detected.

Under the conditions of the study the following endpoints were reached:

24h and 48h EC50 value: > 100 mg/L (nominal)

48h EC100 value: > 100 mg/L (nominal)

48h No-Observed Effect Concentration (NOEC): 100 mg/L (nominal)

48h Lowest Observed Effect Concentration (LOEC): > 100 mg/L (nominal)

Description of key information

Under the conditions of the study the following endpoints were reached:

24h and 48h EC50 value: > 100 mg/L (nominal)

48h EC100 value: > 100 mg/L (nominal)

48h No-Observed Effect Concentration (NOEC): 100 mg/L (nominal)

48h Lowest Observed Effect Concentration (LOEC): > 100 mg/L (nominal)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L

Additional information

The acute toxicity of the test material to Daphnia magna was determined in accordance with the standardised guidelines OECD 202, EU Method C.2, EPA OCSPP 850.1010, JMAFF 2-7-2-1 and The Guidelines for studies on the new chemical substance as required by the Law Concerning the Evaluation of Chemical Substances and Regulation of their Manufacture. The study was performed under GLP conditions. The study was awarded a reliability score of 1 in accordance with the criteria set forth by Klimisch et al. (1997).

Because no toxic response was observed during the preliminary range-finding test, a Limit Test was carried out using only one test concentration (100 mg/L) and one control group in the definitive test.

The test concentration was analytically determined at the start and at the end of the experiment using the HPLC-UV method. The measured concentration was 107 mg/L at the start and 111 mg/L at the end of the test.

As the measured concentrations deviated not more than 20 per cent from the nominal in all cases, biological results are based on the nominal concentration.

Twenty animals, divided into four groups (glass beaker) of five animals each were used at the test concentration and for the control. The test material was formulated directly in ISO Test Medium.

All validity criteria were met during this study.

Although 5 % immobilisation could be observed at the test material group, statistical analysis was not performed since this difference is negligible due to that the accepted control immobilisation is 10 %. In addition to immobility, no abnormal behaviour or appearance of test animals was detected.

Under the conditions of the study the following endpoints were reached: 24h and 48h EC50 value: > 100 mg/L (nominal)

48h EC100 value: > 100 mg/L (nominal)

48h No-Observed Effect Concentration (NOEC): 100 mg/L (nominal)

48h Lowest Observed Effect Concentration (LOEC): > 100 mg/L (nominal)