Cytidine 3'-(dihydrogen phosphate)

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:

September 12, 2017 - September 14, 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)

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)

Specific details on test material used for the study:

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature
- Stability under test conditions: yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 0 (control), 100 mg/L
- Sampling method: Samples were taken from the test solution and from the control solution at the beginning and at the end of the test.
- Sample storage conditions before analysis: The test solution was continuously stirred until sampling in order to ensure its homogeneity during analytical sampling.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A stock solution with a nominal concentration of 100 mg/L was prepared with direct addition of the test item, mixed into the test medium (ISO Medium) using ultrasonic bath (~ 5 minutes). As a Limit test was carried out, further dilution of stock solution was not performed.
- Controls: The dilution water (ISO-medium) was used without addition of the test item.
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): no.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna.
- Source: István Szent University, 2100 Gödöllő, Páter Károly u. 1, Hungary
- Age of parental stock (mean and range, SD): Less than 24 h 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:

246 mg/L (as CaCO3)

Test temperature:

20.1 - 20.9 ºC

pH:

6.85 - 7.32

Dissolved oxygen:

8.0 - 8.3 mg/L

Nominal and measured concentrations:

Nominal: 0 (control), 100 mg/mL
Measured: 0 (control), 102 mg/mL (at the start and at the end of the test). As the measured concentrations deviated not more than 20 percent from the nominal, the biological results are based on the nominal concentration.

Details on test conditions:

TEST SYSTEM
- Test vessel: beaker
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: material: glass, size: 50 mL, fill volume: 40 mL.
- 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: reconstituted water (ISO medium, according to OECD 202).
- Culture medium different from test medium: no.

OTHER TEST CONDITIONS
- Adjustment of pH: no.
- Photoperiod: 16-hour light and 8-hour dark cycle.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
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.

RANGE-FINDING STUDY
- Test concentrations: 0 (control), 0.1, 1, 10, 100 mg/L.
- 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 is tested at least twice a year to demonstrate satisfactory test conditions.

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:

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

Duration:

48 h

Dose descriptor:

LOEC

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

Details on results:

- Behavioural abnormalities: No abnormal behaviour, appearance or any other effect on test animals were detected.
- Mortality of control: 0/20
- Other adverse effects control: no.
- Abnormal responses: no.
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no.
- Effect concentrations exceeding solubility of substance in test medium: no.

Results with reference substance (positive control):

- Results with reference substance valid? yes
- Other: The date of the las study (Study Code: 17/058-023DA) with reference item Potassium dichromate (batch no.: A0345704) is: 08-09 March 2017.
Relevant effect levels: 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.

Table 2: 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	0	0

Data of immobility in each test vessel are detailed in Table 6.

 

Table 3: Temperature measured in the test vessels (°C)

Test group	Replicate	Measuring
		0 h	24 h	48 h
Control	1	20.8	20.3	20.4
	2	20.8	20.3	20.4
	3	20.8	20.3	20.4
	4	20.8	20.3	20.4
100 mg/L (nominal)	1	20.8	20.3	20.4
	2	20.8	20.3	20.4
	3	20.8	20.3	20.4
	4	20.8	20.3	20.4

 

Table 4: Oxygen concentrationmeasured in the test vessels (mg/L)

Test group	Replicate	Measuring
		0 h	48 h
Control	1	8.3	8.3
	2	8.3	8.3
	3	8.3	8.3
	4	8.3	8.3
100 mg/L (nominal)	1	8.0	8.1
	2	8.0	8.1
	3	8.0	8.1
	4	8.0	8.1

 

Table 5: pH measured in the test vessels

Test group	Replicate	Measuring
		0 h	48 h
Control	1	7.06	7.15
	2	7.06	7.19
	3	7.06	7.22
	4	7.06	7.24
100 mg/L (nominal)	1	6.85	7.31
	2	6.85	7.32
	3	6.85	7.32
	4	6.85	7.32

Table 6: Immobilisation of the test animals

Test group	Number of animals	Number of immobilised animals
		24 h	48 h
Control	5	0	0
	5	0	0
	5	0	0
	5	0	0
100 mg/L (nominal)	5	0	0
	5	0	0
	5	0	0
	5	0	0

 

Validity criteria fulfilled:

yes

Remarks:

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

Conclusions:

The 48h-EC50 of the test item in Daphnia magna was found to be higher than 100 mg/L and the NOEC was 100 mg/L, both based on mobility.

Executive summary:

An acute immobilisation test on Daphnia magna was performed in accordance with OECD Guideline 202 and EU method c.2, following GLP. Based on the results obtained in a preliminary 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. Test concentrations were analytically determined (validated method) at the beginning and at the end of the test. As the measured concentration did not deviate more than 20 percent from the nominal, the biological results are basedon the nominal concentration. Twenty animals, divided into four groups of five animals each were exposed to the test item of the control for 48 h. Positive controls (postassium dichromate) are performed at least twice a year to ensure the quality of the results. All validity criteria were met.The 48h-EC50 of the test item in Daphnia magna was found to be higher than 100 mg/L and the NOEC was 100 mg/L, both based on mobility.

Description of key information

Key study: OECD 202 and EU C.2. GLP study. The 48h-EC50 of the test item in Daphnia magna was found to be higher than 100 mg/L and the NOEC was 100 mg/L, both based on mobility.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L

Additional information

Key study: An acute immobilisation test on Daphnia magna was performed in accordance with OECD Guideline 202 and EU method c.2, following GLP. Based on the results obtained in a preliminary 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. Test concentrations were analytically determined (validated method) at the beginning and at the end of the test. As the measured concentration did not deviate more than 20 percent from the nominal, the biological results are based on the nominal concentration. Twenty animals, divided into four groups of five animals each were exposed to the test item of the control for 48 h. Positive controls (potassium dichromate) are performed at least twice a year to ensure the quality of the results. All validity criteria were met. The 48h-EC50 of the test item in Daphnia magna was found to be higher than 100 mg/L and the NOEC was 100 mg/L, both based on mobility.