Registration Dossier

Environmental fate & pathways

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:
other: GLP study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report Date:
2010

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 301 E (Ready biodegradability: Modified OECD Screening Test)
Qualifier:
according to
Guideline:
EU Method C.4-B (Determination of the "Ready" Biodegradability - Modified OECD Screening Test)
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): "ISOMALTULOSE SOLUTION"
- Molecular formula (if other than submission substance):Not applicable.
- Charge No.: 03160483
- Appearance: Yellowish viscous syrup.
- Purity test date: referring to dry weight (HPLC): 33.8 % isomaltulose, 8.0 % dextrose, 12.5 % fructose, 2.8 % isomaltose, 34.7 % trehalulose, 0.5 % saccharose, 7.64 % Dp3+ (higher carbohydrates)
- Solubility: In water: Unlimited
- pH: 4.7 - 7.0 (1:1)
- Density: 1.2 g/cm3 (20 °C)
- Boiling point: > 100 °C
- Conditions of storage: Room temperature.
- Stability at conditions of storage: No data available
- Expiry date: No data available.

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): effluent from a sewate treatment plant, A-2451 Au am Leithagebirge
- Storage conditions: The effluent was aerated by means of filtered compressed air for about 45 minutes before being used for the study
- Preparation of inoculum for exposure: The number of cells of the effluent was determined. Each flask was inoculated with 0.5 mL sewage effluent with approximately 1 600 000 cells per mL.
- Pretreatment: None.
- Initial cell/biomass concentration: approx. 800 000 cells per vessel
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
20 mg/L
Based on:
DOC
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
DOC removal
Details on study design:
TEST CONDITIONS
- Composition of medium: Mineral medium as described in the guidelines
- Additional substrate: None.
- Solubilising agent (type and concentration if used): Not used
- Test temperature: 20.2 to 22.7 °C
- pH: Day 0: 7.4 - 7.5, Day 28: 7.4 - 7.6
- pH adjusted: No.
- Aeration of dilution water: No.
- Suspended solids concentration: Not applicable
- Continuous darkness: Yes.

TEST SYSTEM
- Culturing apparatus: 2L conical flask reaction vessel filled with 1 000 mL test medium.
- Number of culture flasks/concentration: 2 negative control flasks, 2 test substance flask, 1 positive control, 1 toxicity control, 1 abiotic steril control, 1 adsorption control
- Method used to create aerobic conditions: the opening of the vessels was covered with aluminium foil in such a way that the exchang of air was guaranteed.
- Measuring equipment: Measurements were performed with a carbon analyser (TOC-Analysator multi N/C 2000, Analytik Jena).

SAMPLING
- Sampling frequency: Day 0, 2, 4, 7, 10, 14, 18, 22, 25, and 28. Abiotic steril control and adsorption control were determined only on day 28.
- Sampling method: DOC concentrations were determined from the supernatants.
- Sample storage before analysis: Samples were analysed on the same day.

CONTROL AND BLANK SYSTEM
- Inoculum blank: Yes
- Abiotic sterile control: Yes.
- Toxicity control: Yes.
- Other: Adsorption control

STATISTICAL METHODS: no.
Reference substance
Reference substance:
benzoic acid, sodium salt

Results and discussion

% Degradation
Parameter:
% degradation (DOC removal)
Value:
96.2
Sampling time:
28 d
Details on results:
The test substance was 96.2% degraded during the test. The 10-day window started onday 1 and 70% degradation was exceeded at Day 4. The test is therefore valid.

BOD5 / COD results

Results with reference substance:
The plateau of biodegradation was reached on Day 4 and the degradation of sodium benzoate exceeded the pass level of 70 % within 14 days.

Any other information on results incl. tables

The test is considered valid if the difference of extremes of replicate values of the removal of the test substance at the plateau, at the end of the test or at the 10-d window, as appropriate, is less than 20 % and if the percentage degradation of the reference compound has reached the pass levels by day 14. These criteria were fulfilled.

Percent biodegradation

 

test substance

positive control

toxicity control

Day

A13

A14

mean

PK5

TK16

0

0

0

0

0

0

2

43.41

42.62

43.01

87.34

49.79

4

86.16

79.72

82.94

92.87

55.52

7

80.81

80.45

80.63

91.26

84.72

10

83.13

83.27

83.20

95.07

83.33

14

93.07

90.69

91.88

95.94

93.79

18

93.43

91.74

92.59

95.60

93.53

22

95.97

94.85

95.41

97.66

94.13

25

92.54

91.31

91.92

93.69

92.58

28

96.37

95.93

96.15

97.93

95.30

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
The isomaltulose solution can be classified as readily biodegradable, with 96.2% biodegradability achieved by day 28.
Executive summary:

This study examined the potential of the test substance to biodegrade. Sodium benzoate was used as the reference substance. Oxygen measurements were taken at 7, 14, 21, and 28 days. The test substance was 96.2% degraded at the end of 28 days. Results with the reference substance were valid. The test substance is readily biodegradable.

Aim and methods

The ready biodegradability of "ISOMALTULOSE SOLUTION" was determined by the measurement of DOC (dissolved organic carbon) at frequent intervals over a 28 d period. The method used was that described in Part C.4-B of the Regulation (EC) 440/2008 and in the OECD Guideline 301 E.

 

Results

·      The reference substance sodium benzoate was degraded by 95.9 % within 14 days.

·      Degradation in the toxicity control, which contained sodium benzoate and the test substance, was not indicative of an inhibition of the microbial activity by the test substance.

·      The test substance"ISOMALTULOSE SOLUTION"with a nominal starting concentration of 20 mg DOC/L was degraded by 96.2 % after 28 days of incubation at a mean temperature of 21.6 °C. The "10-d window" as defined by the guidelines started at approximately Day 1. 70 % degradation was exceeded at about Day 4.

 

Classification

According to the Guidelines a substance giving a result greater than 70 % loss of DOC in a 10-d window within 28 days is regarded as "readily biodegradable". According to the results of this study,"ISOMALTULOSE SOLUTION" can therefore be classified as readily biodegradable.