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Environmental fate & pathways

Biodegradation in water: screening tests

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Endpoint:
biodegradation in water: inherent biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
from 1990-02-08 to 1991-02-22
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 302 B (Inherent biodegradability: Zahn-Wellens/EMPA Test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge (adaptation not specified)
Details on inoculum:
- Source of inoculum/activated sludge: Provenienza:Hoechst wastewater biological treatment plant
- Concentration of sludge: 10 g/L, 1020 mg/L of dry weight
Duration of test (contact time):
ca. 28 d
Initial conc.:
ca. 44 other: mg C/L
Based on:
DOC
Initial conc.:
122 other: mgO2/L
Based on:
COD
Parameter followed for biodegradation estimation:
DOC removal
Details on study design:
TEST CONDITIONS
- Composition of medium: according to OECD guideline.
- Additional substrate: no
- Solubilising agent (type and concentration if used): no
- Test temperature: 22 °C
- pH: 7.3
- pH adjusted: yes with NaOH
- Aeration of dilution water: no

TEST SYSTEM
- Culturing apparatus: according to OECD guideline.

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic sterile control: no
- Toxicity control: no


Key result
Parameter:
% degradation (DOC removal)
Value:
ca. 4
Sampling time:
28 d
Details on results:
After 29 days of treatment the substance was degraded less than 10%. (~4%)
Results with reference substance:
No test with reference substance was performed.

Biodegradation within 28 days

time elimination biodegradation mean
3h 0% 0% < 10%
7 days 2% 2%
14 days -8% -8%
21 days -2% -2%
28 days 4% 4%
Validity criteria fulfilled:
yes
Interpretation of results:
not inherently biodegradable
Conclusions:
After 29 days of treatment the substance was degraded less than 10%. (~4%). The test substance is considered to be not inherently biodegradable.
Executive summary:

The test substance was tested by OECD 302B (Zahn-Wellens test). After 29 days of treatment the substance was degraded less than 10%. (~4%). The test substance is considered to be not inherently biodegradable.

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
from 1985-11-18 to 1986-02-11
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
other: EEC-Directive 79/831, Part C: Methods for the Determination of Ecotoxicity,
Deviations:
no
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 E (Ready biodegradability: Modified OECD Screening Test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge:municipal wastewater treatment plant, F-Sindlingen
Duration of test (contact time):
ca. 29 d
Initial conc.:
ca. 58 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
DOC removal
Details on study design:
TEST CONDITIONS
- Test vessel: Erlenmeyer flasks 20 mL
- Test temperatur: 21 °C
- pH: 7.1
- pH adjusted: no
-Other: Stock solution: 5 g/L in distilled water

DETERMINATION OF DOC:
Apparatus: IONICS 1270M-TOC analyzer in duplicate. Evaluation after the heights of peak, averaging and expression through their own computere quipment.
Reference substance:
other: hydroquinone
Preliminary study:
Not performed
Test performance:
The validity criteria were met.
Key result
Parameter:
% degradation (DOC removal)
Value:
< 10
Sampling time:
29 d
Details on results:
After 29 days the test substance was biodegraded < 10 %.
Results with reference substance:
After 29 days, ca. 73% of the positive control was degraded.

sampling time control DOC
mg/L
test item DOC, mg/L test item
degradation %
positive control DOC
mg/L
positive control DOC
degradation %
3h 2.9 18.9 5.5 16.6 17
ld 2.1 18.2 9 17.7 11.6
3 d 2 19 5 17 15
7d 2 19 5 5.4 73
10 d 2.1 21.7 0 6.9 65.5
17 d 3.7 21.2 0 5.7 71.5
21 d 0.9 30** - 5.5 72.5
24 d 1.6 22.4 0 5.8 72.5
28 d 2.6 21.4 0 5.4 71
29 d 1.9 19.1 4.5 5.4 73

** outlier

Validity criteria fulfilled:
yes
Interpretation of results:
under test conditions no biodegradation observed
Conclusions:
After 29 days of treatment, below 10% of the substance was degraded. The test substance is considered to be not ready biodegradable
Executive summary:
The ready biodegradability of the test substance was tested in the modified OECD 301E screening test. After 29 days of treatment, below 10% of the substance was degraded. The test substance is considered to be not ready biodegradable.
Endpoint:
biodegradation in water: inherent biodegradability
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Modified guideline study without information on GLP
Qualifier:
according to guideline
Guideline:
OECD Guideline 302 B (Inherent biodegradability: Zahn-Wellens/EMPA Test)
Deviations:
yes
Remarks:
see below
Principles of method if other than guideline:
Deviations from OECD 302 B: Concentration of dyestuff: 100 mg/L; concentration of activated sludge: 0.5 g/L dry material; feeding of the inoculum: each week 100 mg/L yeast extract (in most cases); test duration: up to 42 days; analytical methods: extinction at absorption maximum and DOC (dissolved organic carbon); initial DOC concentration: calculated from stock solution measurement
GLP compliance:
not specified
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, non-adapted
Remarks:
These treatment plants received communal and/or industrial wastewater.
Details on inoculum:
- Source of inoculum/activated sludge: from communal and/or industrial waste water treatment plants.
Duration of test (contact time):
28 d
Initial conc.:
13 mg/L
Parameter followed for biodegradation estimation:
DOC removal
Reference substance:
not specified
Key result
Parameter:
% degradation (DOC removal)
Value:
0
Sampling time:
28 d
Details on results:
9 % adsorption after 3 h (DOC- and photometricdetermination at 580 nm)
Validity criteria fulfilled:
not specified
Interpretation of results:
not inherently biodegradable
Conclusions:
Not biodegradable, but 60% color elimination after 28 days.
Executive summary:

DOC start [mg/L]

DOC ads [%]

DOC elim [%]

DOC cat

col ads [%]

col elim [%]

col cat

elim cal

lambda [nm]

time [d]

13

9

-53

D

9

60

B

-

580

28

Description of key information

The test substance is considered to be not readily / inherently biodegradable. 

Key value for chemical safety assessment

Biodegradation in water:
not biodegradable
Type of water:
freshwater

Additional information

The ready biodegradability of the test substance was tested in the modified OECD 301E screening test and the inherent biodegradability in a modified Zahn-Wellens test. No biodegradation was observed in either test system.