Aluminium triethanolate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

A mixed population of sewage treatment micro-organisms was obtained from the final effluent stage of the Severn Trent Water Plc sewage treatment plant at Loughborough, Leicestershire, UK, which treats predominantly domestic sewage.

The sample of effluent was filtered through coarse filter paper (first approximate 200 mL discarded) and maintained on aeration in a temperature controlled room at a temperature of approximately 21 °C prior to use.

Duration of test (contact time):

14 d

Initial conc.:

100 mg/L

Based on:

ThOD

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: Mineral salts medium as per OECD guideline
- Additional substrate: No
- Solubilising agent (type and concentration if used): NA
- Test temperature: 20 to 21°C
- pH: Ranged from 7.4 to 7.9 across all vessels
- pH adjusted: No
- Suspended solids concentration: 30 mg dry material/L
- Continuous darkness: yes


TEST SYSTEM
- Culturing apparatus: NA
- Number of culture flasks/concentration: Control (inoculum x 2), procedural control (refrence substance x 1), test item (x 2) and toxicity control (test and reference item x 1).
- Measuring equipment: All inoculum control, test item, procedure control and toxicity control vessels were placed in a CES Multi-Channel Aerobic Respirometer.
- Test performed in closed vessels due to significant volatility of test substance: OECD 301F utilises a closed design.
- Test performed in open system: no

SAMPLING
- Sampling frequency: Measurements made daily
- Sampling method: Automatically determined by equipment and software
- Sterility check if applicable: NA
- Sample storage before analysis: Maintained on aeration in a temperature controlled room at ca. 21°C prior to use.

CONTROL AND BLANK SYSTEM
- Inoculum blank: Yes (x 2)
- Abiotic sterile control: No
- Toxicity control: Yes (test substance and aniline)


STATISTICAL METHODS: Not applicable for study design

Reference substance:

aniline

Remarks:

100 mg/L

Preliminary study:

Available information indicates the test substance may hydrolyse to aluminium species and ethanol. Therefore for the purpose of this test it was considered appropriate to add the test item directly to the test vessels without the use of ultrasonication or high shear mixing.

Test performance:

All validity criteria were met

Parameter:

% degradation (O2 consumption)

Value:

92

Sampling time:

14 d

Details on results:

The difference between extremes of replicate BOD values at the end of the 10-Day window was less than 20% and therefore satisfied the validation criterion given in the OECD Test Guidelines.

The test item attained 92% biodegradation after 14 days, calculated from the oxygen consumption values, and satisfied the 10-Day window validation criterion, whereby 60% biodegradation must be attained with 10 days of the biodegradation exceeding 10%. The test item can therefore be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No. 301F.

The toxicity control attained 74% biodegradation after 14 days thereby confirming that the test item was not toxic to the sewage treatment micro-organisms used in the test.

Results with reference substance:

Aniline (procedure control) attained 71% biodegradation after 14 days in a 10-Day Window thereby confirming the suitability of the inoculum and test conditions.

Percentage biodegradation values:

Day	Biodegradation (%)
	Procedure control	Test item			Toxicity control
		R1	R2	Mean
0	0	0	0	0	0
1	0	0	0	0	0
2	0	1	3	2	0
3	0	28	38	33	7
4	7	52	60	56	16
5	35	69	74	72	23
6	56	77	81	79	27
7	61	82	84	83	33
8	63	85	86	86	39
9	66	86	87	87	44
10	67	87	88	88	50
11	69	88	90	89	58
12	70	88	91	90	69
13	70	89	91	90	73
14	71	91	92	92	74

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The test item attained 92% biodegradation after 14 days and satisfied the 10-Day window validation criterion, whereby 60% biodegradation must be attained with 10 days of the biodegradation exceeding 10%. The test item can therefore be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No. 301F.

Description of key information

A guideline GLP compliant ready biodegradation study is available on the substance indicating rapid degradation within 14 days.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater