D-ribose

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution 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

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, domestic, non-adapted

Details on inoculum:

The source of test organisms was activated sludge freshly obtained from a municipal sewage treatment plant: 'Waterschap Aa en Maas', 's-Hertogenbosch, The Netherlands, receiving predominantly domestic sewage.
The freshly obtained sludge was kept under continuous aeration until further treatment. Before use, the sludge was coarsely sieved (1 mm). After treatment, the concentration of suspended solids (SS) was determined to be 3 g/L in the concentrated sludge as used for the test. The magnetically stirred sludge was used as inoculum at the amount of 3 mL per litre of mineral medium, leading to a SS concentration of 8 mg/L.
The test has been accepted internationally for determining the 'ready' biodegradability of test items under aerobic conditions.

Duration of test (contact time):

ca. 28 d

Initial test substance concentration

Initial conc.:

ca. 30 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

pH measurements: At the start of the test (day 0) and on the penultimate day (day 14 for the procedure and toxicity control and day 28 for the inoculum blanks and test item), before addition of concentrated HCl.
Temperature of medium: Continuously in a vessel with Milli- RO water in the same room.

Reference substance

Reference substance:

acetic acid, sodium salt

Results and discussion

% Degradation

Key result

Parameter:

% degradation (CO2 evolution)

Value:

> 60

Sampling time:

10 d

Details on results:

The ThCO2 of D-ribose was calculated to be 1.47 mg CO2/mg. The ThCO2 of sodium acetate was calculated to be 1.07 mg CO2/mg.

The relative biodegradation values calculated from the measurements performed during the test period revealed 88% and 73% biodegradation of D-ribose, for vessel A and B, respectively (based on ThCO2). Furthermore, average biodegradation of D-ribose in vessel nA and B reached ≥60% within a 10-day window.
In the toxicity control, more than 25% biodegradation occurred within 14 days (50%, based on ThCO2). Therefore, the test item was assumed not to inhibit microbial activity.
Functioning of the test system was checked by testing the reference item sodium acetate, which showed a normal biodegradation curve.

BOD5 / COD results

Results with reference substance:

Functioning of the test system was checked by testing the reference item sodium acetate, which showed a normal biodegradation curve.

Any other information on results incl. tables

The temperature recorded in a vessel with water in the same room varied between 22 and 23°C. The pH values of the different test media are presented in the following table:

TEST MEDIUM	AT THE STRART OF THE TEST	DAY 14	DAY 28
Blank control (A)	7.6	-	7.6
Blank control (B)	7.6	-	7.6
Procedure control	7.6	7.8	7.6
D-ribose item (A)	7.7 > 7.6	-	7.6
D-ribose item (B)	7.6	-	7.6
Toxicity control	7.7 > 7.6	7.8	-

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

According to the OECD 301B, D-ribose was readily biodegradable under the conditions of the modified Sturm test.