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Environmental fate & pathways

Biodegradation in water: screening tests

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Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
08/1996-01/1997
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1997
Report date:
1997

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)
GLP compliance:
yes

Test material

Constituent 1
Reference substance name:
Reaction products of coconut oil with polyethyleneglycol and 2-ethyl-2-(hydroxymethyl)propane-1,3-diol
EC Number:
640-964-5
Cas Number:
218451-68-4
Molecular formula:
not applicable because UVCB
IUPAC Name:
Reaction products of coconut oil with polyethyleneglycol and 2-ethyl-2-(hydroxymethyl)propane-1,3-diol
Constituent 2
Reference substance name:
Coconut oil, reaction product with polyethylene glycol and trimethylolpropane
IUPAC Name:
Coconut oil, reaction product with polyethylene glycol and trimethylolpropane
Details on test material:
- Name of test material (as cited in study report): Marlowet 4753
- Physical state: liquid, cristalline
- Analytical purity: 98.4 %
- Impurities (identity and concentrations): not mentioned
- Stability under test conditions: > 1 year

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge: domestic sewage plant (Marl-East, Germany)
- Laboratory culture: no
- Storage conditions: not mentioned
- Storage length: not mentioned
- Preparation of inoculum for exposure: according to prescipt (not specified)
- Pretreatment: not mentioned
- Concentration of sludge: 28.1 mg/L suspended solids; dry weight of inoculum: 4.2 g/L
- Initial cell/biomass concentration: 56 x 10000 cfu/mL (colony forming units/mL)
- Water filtered: not mentioned
Duration of test (contact time):
29 d
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
TEST CONDITIONS
- Composition of medium: not specified
- Additional substrate: none
- Solubilising agent (type and concentration if used): not used
- Test temperature: . . °C
- pH:
- pH adjusted: no
- Aeration of dilution water: not specified
- Suspended solids concentration: . . mg/L
- Continuous darkness: not mentioned
- Other: none

TEST SYSTEM
- Culturing apparatus: 5000 mL glass vessels containing culture samples
- Number of culture flasks/concentration: 2 bottles, one concentration
- Method used to create aerobic conditions: not mentioned
- Method used to create anaerobic conditions: not applicable
- Measuring equipment: carbon analyzer (Shimadzu)
- Details of trap for CO2: collection of carbon dioxide as sodium carbonate with sodium hydroxide solution (no further details mentioned)
- Other: none


SAMPLING
- Sampling frequency: on days 0, 1, 6, 9, 14, 19, 23, 28 and 29
- Sampling method: not mentioned
- Sample storage before analysis: not mentioned
- Other: none


CONTROL AND BLANK SYSTEM
- Inoculum blank: yes (2 vessels with inoculum without test substance)
- Abiotic sterile control: not performed
- Toxicity control: not performed
- Other: none


STATISTICAL METHODS: no statistics performed
Reference substance
Reference substance:
benzoic acid, sodium salt
Remarks:
25 mg/L final test medium (14.6 mg DOC/L)

Results and discussion

Preliminary study:
not performed
Test performance:
Procedure: The test substance was poured into a defined, liquid mineral medium, which was inoculated with an inoculum from activated sludge and aerated at .20.4. °C (17.7 - 22 °C). The released CO2 is bound in caustic soda solution in the form of sodium carbonate. The degradation was followed over the duration of the test of 29 days at the days 0, 2, 5, 9, 12, 16, 19, 23, 28 and 29 d of sampling as stated above via a TIC analysis (total inorganic carbon) of the bound CO2 with a carbon analyzer of Shimadzu. One day before the end of the test (28th day) a pH-measurement was conducted and the remaining dissolved CO2 was driven out by acidification of the test preparation, the degradation values ascertained on the 29th day (end of incubation) are therefore related to the 28th day.
Preparation of the mineral medium: Two days before the beginning of the test (addition of the test substance) 35 L of the mineral medium were prepared and erated overnight. On the following day 2400 mL were filled into the individual test containers and, after inoculation with the inolculum, filled with the mineral medium up to 3 L.
Dosage of the test material: The test material was weighed exactly by means of a weighing aid (reaction vessel from Eppendorf, cut-off cover) and was put into the test vessels together with the weighing aid.
% Degradation
Key result
Parameter:
% degradation (CO2 evolution)
Value:
ca. 79
Sampling time:
28 d
Remarks on result:
other: after acification
Details on results:
see below

BOD5 / COD results

Results with reference substance:
see below

Any other information on results incl. tables

Table: Degradation kinetic

 sampling time [days]  degradation [%]         
   test substance        reference substance
  vessel 1  vessel 2  mean  
1 -1 -1 -1 -1
2 13 16 15 4
5 33 38 36 74
9 61 64 63   78
12 65 70 68   78
16 66 69 68  74
19 79 76  78 85
23 79 80 80  86
28 79 80 80  88
29 (after acidification) 80 78  79

86

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Executive summary:

The purpose of this test was the measurement of the biodegradability of Coconut oil, reaction product with polyethylene glycol and trimethylolpropane in an aerobic, aqueous medium. The study was conducted according to the EU Method C.4 -C (Determination of the "Ready Biodegradabality - Carbon Dioxide Evolution test).

Under the present test conditions, 79 % biodegradability was determined for Coconut oil, reaction product with polyethylene glycol and trimethylolpropane after 28 days. The substance reached the 10d-window (>= 60 % were degradated during 10 days).

Coconut oil, reaction product with polyethylene glycol and trimethylolpropane is regarded as "readily biodegradable".