Alcohols, C16-18 and C18-unsatd., ethoxylated

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

28 OCT - 26 NOV 2004

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

GLP compliance:

yes (incl. QA statement)

Remarks:

Niedersächsisches Umweltministerium, Hannover, Germany

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, predominantly domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): sewage plant at Hildesheim which comprises mostly municipal sewage and hardly industrial chemical waste.
- Pretreatment: The activated sludge was maintained in an aerobic condition by aeration for four hours and then homogenized with a mixer. The sludge was filtered and the fitrate (30 mL) was subsequently used to initiate inoculum.
- Initial cell/biomass concentration: Colony forming units in the test vessels: 10 exp 5 - 10 exp 6 CFU/L

Duration of test (contact time):

28 h

Initial conc.:

20 mg/L

Based on:

test mat.

Initial conc.:

2.43 mg/L

Based on:

ThOD

Initial conc.:

13.3 mg/L

Based on:

TOC

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: Mineral nutrient solution according to OECD 301 B
- Test temperature: 20 - 24 °C
- pH: 7.59 - 7.93


TEST SYSTEM
- Culturing apparatus: 5000 mL test vessels (brown glass) filled with 3000 mL test medium
- Number of culture flasks/concentration: 2 - test item, 1 - toxic control, 2 - control


SAMPLING
- Sampling frequency: day 1, 4, 6, 8, 11, 14, 18, 21, 25, 28 and 29

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2 replicates
- Reference control: 1 replicate
- Toxicity control: 1 replicate

Reference substance:

acetic acid, sodium salt

Parameter:

% degradation (CO2 evolution)

Value:

99

Sampling time:

28 d

Details on results:

The toxicity control reached 73% biodegradation after 14 days.

Results with reference substance:

87% degradation after 28 days

Table 1:

	Biodegradation (%)
Day	6	14	21	28
Test substance, 20 mg/L - 1streplicate	43	81	90	98
Test substance, 20 mg/L - 2nd replicate	43	89	100	100
Functional control 35 mg/L	48	71	88	100
Toxicity control 20 mg/L test item + 35 mg/L reference item	34	73	81	87

Table 2: Validity criteria OECD 301 B

Criterion from the guideline	Outcome	Validity criterion fulfilled
Difference of extremes of replicate values of the removal of the test chemical at the plateau, at the end of the test or at the end of the 10-d window, as appropriate, is less than 20%.	<20%	yes
Percentage degradation of the reference compound reached the pass level by day 14 (≥ 60%).	87% after 14 days.	yes
The toxicity control should degrade to at least 35% (based on DOC) or at least 25% (based on ThOD or ThCO2) within 14 d.	73% after 14 days	yes
The IC content of the test substance suspension in the mineral medium at the beginning of the test must be less than 5% of the TC.	<5%	yes
The total CO2 evolution in the inoculum blank at the end of the test should not normally exceed 40 mg/L medium and must be below 70 mg/I.	46 mg/L	yes

Validity criteria fulfilled:

yes

Remarks:

Please refer to table 2 at "Any other information on results incl. tables"

Interpretation of results:

readily biodegradable

Reference 2

Endpoint:

biodegradation in water: screening tests

Type of information:

experimental study

Adequacy of study:

other information

Study period:

11 SEP - 23 SEP 1987

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Qualifier:

according to guideline

Guideline:

OECD Guideline 302 B (Inherent biodegradability: Zahn-Wellens/EMPA Test)

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

not specified

Details on results:

The result of the study do not allow a statement whether the substance is readily biodegradable or not

Interpretation of results:

other: no interpretation of results possible

Reference 3

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

20 SEP - 18 OCT 2004

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): From aeration tank of a municipal waste water treatment plant (ARA Werdhölzli, Zürich), no adapted, not pre-conditioned.
- Pretreatment: Prior the test the sludge was washed twice with tap water.
- Concentration of sludge: 30 mg/L

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: Aerobic mineral salts medium prepared with deionised water
- Test temperature: 22 +/- 0.5 °C
- Suspended solids concentration: 30 mg/L
- Continuous darkness: yes, Thermostat cabinet


TEST SYSTEM
- Culturing apparatus: 2500 mL closed glass bottles, containing a total volume of test solution of 2000 mL
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: aeration with CO2-free air, fitted to gas-absorption bottles (containing 125 mL of 0.15 M NaOH)
- Details of trap for CO2 and volatile organics if used: gas-absorption bottles filled with NaOH

SAMPLING
- Sampling frequency: daily

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2 replicates
- Procedure control: 1 replicate
- Abiotic sterile control: no
- Toxicity control: no

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

63

Sampling time:

28 d

Results with reference substance:

77% biodegradation after 14 d

Interpretation of results:

readily biodegradable

Reference 4

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1972

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

other: garden-mould suspension

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): garden-mould suspension (1 mL/L about 10 exp 3 - 10 exp. 5 cells/mL. 100 g garden-mould from the Henkel garden center was given to 1 L tap water, shaken vigorously and filtered through a coarse paper filter, the first 200 mL being discarded.

Duration of test (contact time):

30 d

Initial conc.:

1.84 mg/L

Based on:

COD

Initial conc.:

4.6 mg/L

Based on:

COD

Parameter followed for biodegradation estimation:

O2 consumption

Parameter:

% degradation (O2 consumption)

Value:

65 - 96

Sampling time:

30 d

Interpretation of results:

readily biodegradable

Description of key information

Readily biodegradable: 99% in 28 days (OECD 301B) 

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

Three reliable studies on the ready biodegradability of Alcohols, C16 -18 and C18-unsatd., ethoxylated are available.

The key study was conducted according to OECD guideline 301 B . The study was conducted with a test substance concentration of 20 mg/L and with activated non-adapted sludge as inoculum. Based on CO2 evolution a degradation rate of 99% after 28 days was determined. The results is supported by a study following OECD 301 F. Test medium containing a test substance concentration of 100 mg/L was inoculated with non-adapted activated sludge. After 28 days a degradation rate of 63% was recorded based on O2 consumption of the inoculum.

In a supporting study set up according to OECD 301 D a garden-mould suspension was used as inoculum. A degradation rate of 65 – 96% was determined after 30 days of incubation.

In addition a short summary is available which describes an inherent biodegradation test . However, an interpretation of the results of the study is not possible due to insufficient data reported.

Based on the available test results, Alcohols, C16 -18 and C18 unsatd., ethoxylated is assessed as readily biodegradable according to OECD criteria.