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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 July 2017 to 30 October 2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

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

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
Qualifier:
according to guideline
Guideline:
EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
Castor oil, hydrogenated, ethoxylated
EC Number:
500-147-5
EC Name:
Castor oil, hydrogenated, ethoxylated
Cas Number:
61788-85-0
Molecular formula:
C57H110O9 (C2H4O)n where n = 1-6.5
IUPAC Name:
Castor oil, hydrogenated, ethoxylated
Test material form:
solid
Remarks:
pasty wax

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge: Totnes Sewage Treatment Works, Totnes, Devon, UK
- Storage conditions: aerated at room temperature at pH 7.0 ± 1.0.
- Storage length: 2 days
- Preparation of inoculum for exposure: Six days prior to the exposure start the activated sludge was centrifuged, washed and re suspended in the mineral medium and the solids concentration determined. This sludge was then diluted in medium, added to test bottles and stirred until required for use. The seeded mineral medium was pre-conditioned for six days to reduce the blank oxygen uptake readings in the test.
- Concentration of sludge: 30 mg/L
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
Remarks:
calculated as BOD/COD
Details on study design:
TEST CONDITIONS
- Composition of medium: according to the guideline
- Additional substrate: none
- Solubilising agent (type and concentration if used): none
- Test temperature: 22 ± 1 °C
- pH: 7.4 ± 0.2 (actual 6.78-7.32)
- pH adjusted: no
- Sludge concentration: 30 mg/L
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: dark glass 500 mL bottle placed in incubator
- Number of culture flasks/concentration: 3
- Method used to create aerobic conditions: continuously stirred
- Measuring equipment: Oxitop respirometer
- Details of trap for CO2 and volatile organics if used: KOH

Examiniations
- Frequency: daily
- Method: measurement of decrease in pressure over 240 min period

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes (3 replicates)
- Abiotic sterile control: none
- Toxicity control: yes (3 replicates)

STATISTICAL METHODS: NA
Reference substance
Reference substance:
benzoic acid, sodium salt

Results and discussion

% Degradationopen allclose all
Parameter:
other: % degradation BOD/COD
Value:
15
Sampling time:
5 d
Remarks on result:
other: start of degradation on day 3
Parameter:
other: % degradation BOD/COD
Value:
55
Sampling time:
28 d
Parameter:
other: % degradation BOD/COD
Value:
64
Sampling time:
42 d
Details on results:
Initial pH 7.32, at 28 days 6.78-7.15for substance
Initial pH 7.2, at 28 days 7.3 for inoculum blank

Any other information on results incl. tables

Day

Biodegradationb(%)

Reference Substance

Biodegradationb(%)

substance

Biodegradationb(%)

Tox control

Mean

Mean

Mean

5

64

15

26

10

72

27

31

15

75

39

35

20

76

47

38

25

77

53

40

30

78

56

42

35

79

59

44

40

80

62

45

42

80

64

46

Biodegradation (%) =       Biological Oxygen Demand (g O2/g)× 100 /ThOD (1.67 g O2/g) and/or COD (2.16 g O2/g)

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
inherently biodegradable
Conclusions:
The substance is inherently biodegradable
Executive summary:

Subject

Determination of Ready Biodegradability

Guideline

OECD 301F: Manometric respirometry

Test concentration

Control and 100 mg/L

Length of test

42 days

Nominal

test temperature

22 ± 1°C

Mean degradation after 28 days

55%

Mean degradation after 42 days

64%

Classification

Inherently biodegradable

Conclusions

The substance attained a mean level of biodegradation (based on the BOD:COD ratio) of 64% after 42 days and the results showed good replication.

The substance exhibited the potential for rapid degradation and can be classified as inherently biodegradable.