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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:
7 Dec 2016 - 12 Jan 2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018
Report date:
2017

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Remarks:
Landesamt für Umwelt, Wasserwirtschaft und Gewerbeaufsicht, Mainz, Germany

Test material

Constituent 1
Chemical structure
Reference substance name:
Disodium 4,5-dihydroxybenzene-1,3-disulphonate
EC Number:
205-741-5
EC Name:
Disodium 4,5-dihydroxybenzene-1,3-disulphonate
Cas Number:
149-45-1
Molecular formula:
C6H6O8S2.2Na
IUPAC Name:
disodium 4,5-dihydroxybenzene-1,3-disulphonate
Test material form:
solid: particulate/powder

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
sewage, predominantly domestic (adaptation not specified)
Details on inoculum:
- Source of inoculum/activated sludge: The sludge was taken from the activation basin of the ESN (Stadtentsorgung Neustadt) sewage treatment plant, Im Altenschemel, NW-Lachen-Speyerdorf. Date of collection: 2016-12-09
- Pretreatment: The sludge was filtrated, washed with tap water (2x), then washed with and re-suspended in test medium. It was then aerated until use.
- Concentration of sludge: The dry matter was determined as 4160 mg suspended solids/L.
Duration of test (contact time):
28 d
Initial test substance concentrationopen allclose all
Initial conc.:
90 mg/L
Based on:
test mat.
Initial conc.:
20 mg/L
Based on:
DOC
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
TEST CONDITIONS
- Composition of medium: OECD guideline test medium
- Test temperature: 18.7 – 21.7 °C
- pH: 6.3 - 7.3
- pH adjusted: no
- Aeration of dilution water: yes
- Suspended solids concentration: 4160 mg/L
- Continuous darkness: yes


TEST SYSTEM
- Culturing apparatus: 2000 mL-SCHOTT-flasks were used as test vessels, 100 mL scrubber flasks as absorbent vessels.
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: Aeration with purified (by activated charcoal), CO2-scrubbed, moistened air.
- Measuring equipment: Carbon analyser TOC multi N/C 2100S, Analytik Jena
- Test performed in open system: no


SAMPLING
- Sampling frequency: day 0, 2, 4, 7, 9, 11, 15, 17, 23 and 29
- Sampling method: 10 samples of 1 mL were taken from each flask.
- Sterility check if applicable: no
- Sample storage before analysis: not stated


CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic control: yes
- Toxicity control: yes
Reference substance
Reference substance:
aniline

Results and discussion

% Degradation
Parameter:
% degradation (CO2 evolution)
Value:
9.2
Sampling time:
29 d
Remarks on result:
other: mean of two flasks
Details on results:
The test item is considered as not readily biodegradable. The degree of biodegradation reached 9% after 28 days and the 10-day-window was not met.
Abiotic degradation reached 15.7 %.

BOD5 / COD results

Results with reference substance:
89.7% after 29 days

Any other information on results incl. tables

Biodegradation results [%]:

Day  Positive Control 1 Positive Control 2 Positive Control Mean Test 1  Test 2 Test Mean Abiotic Control Toxicity Control
2 -0.4 1.3 0.5 -0.3 2.5 1.1 6.4 0.5
4 21.5 24.2 22.9 2.3 2 2.1 7.2 2.7
7 60.9 66 63.4 0.2 0.3 0.3 7.9 16.3
9 72.3 81.2 76.8 2.5 5 3.7 8.6 23.9
11 77.3 84.9 81.1 1.1 5.1 3.1 8.4 26.6
15 80.9 87.4 84.2 0.9 5.7 3.3 8.1 30
17 85.8 95 90.4 2.4 8.9 5.6 2.9 32.6
23 86.2 90.4 88.3 1.8 10.1 6 9 33.7
29 87.2 92.2 89.7 5.9 12.5 9.2 15.7 40.4

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
not readily biodegradable