2-ketogluconic acid, calcium salt

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Version / remarks:

The sealed vessel test is a CO2 production test based on OECD Guideline 301B. The test system is closed and is therefore suitable for the examination of volatile materials.

Principles of method if other than guideline:

The sealed vessel test is a CO2 production test based on OECD Guideline 301B. The test system is closed and is therefore suitable for the examination of volatile materials.

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2-ketogluconic acid, calcium salt

EC Number:

919-553-2

Cas Number:

28098-92-2

Molecular formula:

C6H10O7.xCa

IUPAC Name:

2-ketogluconic acid, calcium salt

Test material form:

solid

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

10 mg/L

Based on:

other: Nominal concentration of Organic Carbon

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation 1

Parameter followed for biodegradation estimation:

CO2 evolution

Parameter followed for biodegradation estimation 2

Parameter followed for biodegradation estimation:

inorg. C analysis

Remarks:

Dissolved Inorganic Carbon

Details on study design:

The test used was the sealed vessel test which is suitable for determining the ready and ultimate biodegradability of organic substances. The test was conducted in 160 mL vessels (hypovials) containing 100 mL mineral salts medium inoculated with secondary effluent and the respective test or reference substance. Multiple vessels are prepared per substance sealed with butyl rubber septa and an aluminium crimp seal. The headspace in each vessel has a volume of 60 mL and, when filled with air, contains approximately 6 times the mass of oxygen required for the complete oxidation of the test item.

The sealed vessels are incubated at 20 °C on a rotary shaker. At intervals during the 28 day test period (Day 3, 7, 10, 14, 17, 21, 24 and 28) a vessel is removed and concentration of carbon dioxide in the headspace gas determined. The seal is then broken and the concentration of inorganic carbon in the test medium is also determined. The total inorganic carbon in the vessel is calculated and corrected by subtracting the total inorganic carbon produced in the Control. The Control vessels were identical to the test vessels except for the omission of the test substance. From a knowledge of the initial organic carbon concentration added as a test substance, the extent of mineralisation can be determined.

Results and discussion

% Degradation

Key result

Parameter:

% degradation (CO2 evolution)

Value:

75

Sampling time:

28 d

Applicant's summary and conclusion

Validity criteria fulfilled:

not specified

Interpretation of results:

readily biodegradable

Conclusions:

TThe Ready Biodegradability of Stimulhyal was determined by the Manometric Respirometry Test.

Stimulhyal undergoes 75% biodegradation after 28 days in the test conditions. The 10-day window criterion is also fulfilled (27% biodegradation on day 3 and 64% on day 13).

Stimulhyal did not inhibit the intrinsic respiration of the inoculum at the test concentration and was therefore considered to be non-toxic to the inoculum at the test concentration.

Thus, Stimulhyal should be regarded as readily biodegradable according to this test.