D-ribose

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2018/2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

D-ribose

EC Number:

200-059-4

EC Name:

D-ribose

Cas Number:

50-69-1

Molecular formula:

C5H10O5

IUPAC Name:

D-ribose

Test material form:

solid: particulate/powder

Details on test material:

Dry powder, white to slightly yellow

Specific details on test material used for the study:

Appearance: White to slightly yellow powder
Batch: Q0926501
Purity/Composition: 99.3%
Test item storage: At room temperature protected from light
Stable under storage conditions until: 30 November 2019 (expiry date)

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Frequency: at t=0 h and t=48 h.
Volume: 40 mL from the approximate centre of the test vessels.
Storage: Samples were stored in a refrigerator (2-8°C) until analysis.

Test solutions

Details on test solutions:

The batch of D-ribose tested was a white to slightly yellow powder with a purity of 99.3% and completely soluble in test medium at the solutions prepared. No correction was made for the purity/composition of the test item.
Preparation of test solutions started with the highest concentration of 100 mg/L in the range-finding test and a stock solution of 1000 mg/L in the limit test applying a 10-15 minute period of magnetic stirring to accelerate dissolution of the test item in medium. Lower test concentrations were prepared by subsequent dilutions of the highest concentration or stock solution in test medium. All test solutions were clear and colorless at the end of the preparation procedure.
Any residual volumes were discarded.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

* Species: Daphnia magna (Crustacea, Cladocera) (Straus, 1820), at least third generation, obtained by a cyclical parthenogenesis under specified breeding conditions.
* Source: In-house laboratory culture with a known history.
* Reason for selection: This system has been selected as an internationally accepted invertebrate species.
* Validity of batch Daphnids originated from a healthy stock, 2nd to 5th brood, showing no signs of stress such as mortality >20%, presence of males, ephippia or discoloured animals and there was no delay in the production of the first brood.
* Characteristics: Daphnia, less than 24 hours old, from parental daphnids of more than two weeks old.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test conditions

Test temperature:

The temperature continuously measured in a temperature control vessel varied between 20 and 21°C during the test, and complied with the requirements as laid down in the study plan (18-22°C, constant within ±1°C).

pH:

pH was only measured in the control and the highest test concentration.
pH was:
- for control: 7.6 at t=0h and 8.1 at t=48h
- for highest test concentration (i.e. 100 nominal concentration mg/L): 7.7 at t=0h and 8.1 at t=48h

Dissolved oxygen:

Dissolved oxygen concentrations was only measured in the control and the highest test concentration.
Dissolved oxygen was:
- for control: 8.9 mg/L at t=0h and 8.8 mg/L at t=48h
- for highest test concentration (i.e. 100 nominal concentration mg/L): 9.0 mg/L at t=0h and 8.7 mg/L at t=48h

Nominal and measured concentrations:

Measured concentration reached 96 to 98% of nominal concentration.

Details on test conditions:

A range-finding test was performed to provide information about the range of concentrations to be used in the final test. Test procedure and conditions were similar to those applied in the limit test with the following exceptions:
- Ten daphnids per concentration (in duplicate, 5 per vessel) were exposed to a range of 0.10 to 100 mg/L increasing by a factor of 10 and to a control.
- Dissolved oxygen concentrations and pH were only measured in the control and the highest test concentration.
- No sampling for determination of actual exposure concentrations was performed.

Reference substance (positive control):

no

Results and discussion

Effect concentrations

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

Details on results:

No immobility was observed in the control or in the limit concentration throughout the exposure period. The responses recorded in this test allowed for reliable determination of an EC50 and were in agreement with what was expected based on the results of the range-finding test.
At the start and end of the test, the carbon concentration observed at the limit concentration was comparable to the expected nominal carbon concentration of 40 mg/L. The carbon concentration measured in the limit concentration of 100 mg/L remained stable during the test period, i.e. was 94% of the initially measured concentration.

Any other information on results incl. tables

A sample taken from the 1000 mg/L stock solution was analysed. The measured concentration was 98% of nominal at the start of the test and thus confirmed correct preparation of the test solution.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

No immobility was observed in the control or any of the concentrations tested throughout the test.