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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
Study period:
2008-05-15 to 2008-06-12
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP, Guideline study.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2008
Report date:
2008

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
Version / remarks:
, 1992
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)
Version / remarks:
, 1992
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Remarks:
signed 2007-03-21

Test material

Constituent 1
Chemical structure
Reference substance name:
3,5-dihydroxy-4-[3-(4-hydroxyphenyl)propanoyl]phenyl 2-O-(6-deoxy-α-Dmannopyranosyl)-β-D-gulopyranoside
EC Number:
700-320-7
Cas Number:
18916-17-1
Molecular formula:
C27H34O14
IUPAC Name:
3,5-dihydroxy-4-[3-(4-hydroxyphenyl)propanoyl]phenyl 2-O-(6-deoxy-α-Dmannopyranosyl)-β-D-gulopyranoside
Constituent 2
Reference substance name:
1-[4-[[2-O-(6-Deoxy-L-mannopyranosyl)-D-glucopyranosyl]oxy]-2,6-dihdroxyphenyl]-3(4-hydroxyphenyl)-1-propanone
IUPAC Name:
1-[4-[[2-O-(6-Deoxy-L-mannopyranosyl)-D-glucopyranosyl]oxy]-2,6-dihdroxyphenyl]-3(4-hydroxyphenyl)-1-propanone
Details on test material:
- Name of test material (as cited in study report): Naringin dihydrochalcone (DHC); 1-[4-[[2-O-(6-Deoxy-L-mannopyranosyl)-D-glucopyranosyl]oxy]-2,6-dihdroxyphenyl]-3(4-hydroxyphenyl)-1-propanone
- Substance type: solid, whitish powder
- Physical state: technical product
- Storage condition of test material: 15 - 25 °C, dark, dry, don't freeze, keep away from strong light and heat

- no further significante details stated

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): sewage treatment plant Ruhrverband Kläranlage, Schmallenberg, Germany (mainly municipal water)
- Method of cultivation: aerobic
- Storage conditions: kept aerobic until use
- Storage length: samples withdrawn on 2008-05-15
- Preparation of inoculum for exposure: wash once with mineral medium after arrival at laboratory
- Concentration of sludge used in the test: 29.6 mg dry mass/litre
- Water filtered: no

- no further significante details stated
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
100 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
TEST CONDITIONS
- Composition of medium: deionized water; 10 mL/L (a) KH2PO4 (8.50 g/L), K2HPO4 (21.75 g/L), Na2HPO4 x 2 H2O (33.40 g/L), NH4Cl (0.50 g/L); 1 mL/L (b) CaCl2 x 2 H2O (36.40 g/L); 1 mL/L (c) MgSO4 x 7 H2O (22.50 g/L); 1 mL/L (d) FeCl3 x 6 H2O (0.25 g/L)
- Test temperature: 22 +/- 0.1 °C
- pH: 7.4 +/- 0.2
- pH adjusted: no
- Aeration of dilution water: the suspension was stirred during the whole test
- Continuous darkness: yes


TEST SYSTEM
- Culturing apparatus: 500 mL glass vessels with a medium volume of 250 mL
- Number of culture flasks/concentration: 2 vessels each for test suspension, inoculum blank, abiotic control, procedural control, toxicity control
- Method used to create aerobic conditions: the suspension was stirred during the whole test
- Measuring equipment: SAPROMAT respirometer (VOITH Inc.) for measuring and recording of oxygen demand
- Test performed in closed vessels due to significant volatility of test substance:


SAMPLING
- Sampling frequency: daily


CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic sterile control: yes
- Toxicity control/ procedural control: yes, with reference item

- no further significante details stated
Reference substance
Reference substance:
benzoic acid, sodium salt
Remarks:
100 mg/L medium

Results and discussion

Preliminary study:
not applicable
Test performance:
not applicable
% Degradationopen allclose all
Parameter:
% degradation (O2 consumption)
Value:
76
Sampling time:
28 d
Parameter:
% degradation (O2 consumption)
Value:
64
Sampling time:
13 d
Remarks on result:
other: 10d window starting at day 3
Details on results:
- see attachmed background material (table 9 of the report)

BOD5 / COD results

Results with reference substance:
- 81 % degradation within the first 14 days

Any other information on results incl. tables

The test is considered valid, as

-    the difference of extremes of replicate values of the removal of the test item at the end of the 10-day-window and the end of the test was less than 20 %,

-    the percentage degradation of the reference item has exceeded the pass level of 60 % by day 14,

-    the oxygen uptake of the inoculum blank is < 60 mg/L in 28 days and the pH value was inside the range of 6.0 - 8.5.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
see "overall remarks"
Interpretation of results:
readily biodegradable
Conclusions:
The biodegradation of Naringin DHC in the static test was found to be 76 % after 28 days. The biodegradation within the 10-day-window was 64 %. The 10-day window started at day three. No real lag phase / adaptation phase was noticeable.
With 3 %, no significant abiotic degradation of Naringin DHC was noticeable after 28 days of incubation.
The biodegradation of the item mixture in the toxicity control was found to be 66 % after 14 days of incubation. Thus, the demanded threshold value of 25 % is exceeded and the test item Naringin DHC can be identified as non toxic in a ready biodegradability test.
The reference item sodium benzoate was degraded to 81 % within the first 14 days.
Due to a biodegradation above 60 % within a 10-day-window, the test item Naringin DHC can be identified as readily biodegradable.

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