Castor oil, hydrogenated, ethoxylated

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 guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Test guideline 2

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

Test material information

Constituent 1

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

% Degradation

% Degradation 1

Parameter:

other: % degradation BOD/COD

Value:

15

Sampling time:

5 d

Remarks on result:

other: start of degradation on day 3

% Degradation 2

Parameter:

other: % degradation BOD/COD

Value:

55

Sampling time:

28 d

% Degradation 3

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	Biodegradation^b(%) Reference Substance	Biodegradation^b(%) substance	Biodegradation^b(%) 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.