Octan-1-ol, ethoxylated

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

Study period:

31 Jan - 28 Feb 2019

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)

Version / remarks:

1992

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Sewage treatment micro-organisms from the final effluent stage of the Severn Trent Water Plc sewage treatment plant at Loughborough, Leicestershire, UK (obtianed on 28 Jan 2019). The STP treats predominantly domestic sewage.
- Pretreatment: 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 temperatures of between 20 and 21 °C prior to use.

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: according to OECD guideline
- Solubilising agent (type and concentration if used): the test item was dissolved directly in mineral medium with the aid of ultrasonication for appr. 20 minutes.
- Test temperature: 21 - 22 °C
- pH: 7.4-7.5
- pH adjusted: no
- Continuous darkness: no (diffuse light)


TEST SYSTEM
- Culturing apparatus: CES Multi-Channel Aerobic Respirometer
- Number of culture flasks/concentration: 3
- Method used to create aerobic conditions: the pressure reduction caused by the adsobtion of carbon dioxide triggers an electrolytic process, generating oxygen and restoring the pressure in the sample flask.
- Details of trap for CO2 and volatile organics if used: ethanolamine solution (50% v/v)


CONTROL AND BLANK SYSTEM
- Inoculum blank: 3 replicates
- Reference item control: 2 replicates
- Toxicity control: 2 replicates (100 mg test item/L and 100 mg aniline/L)

Reference substance:

aniline

Parameter:

% degradation (O2 consumption)

Value:

100

Sampling time:

28 d

Details on results:

Degradation rate of toxicity control: 76% after 14 days. The test substance is not toxic to micro-organisms.

Results with reference substance:

Reference contol (Anilin): 76% degradation after 14 days (ten-day window criterion met)

Table 1: Percentage Biodegradation Values

Day	Biodegradation (%)
	Procedure Control	Test Item			Toxicity Control
		R1	R2	Mean
0	0	0	0	0	0
1	0	1	0	1	0
2	0	23	23	23	10
3	0	29	29	29	12
4	3	39	39	39	17
5	21	54	53	54	28
6	39	63	63	63	39
7	59	69	70	70	49
8	64	73	74	74	62
9	66	77	77	77	71
10	67	80	81	81	73
11	69	82	86	84	74
12	70	84	89	87	75
13	70	88	91	90	76
14	71	90	93	92	76
15	71	91	94	93	77
16	72	92	95	94	78
17	72	93	96	95	78
18	72	94	97	96	78
19	73	94	98	96	79
20	73	95	98	97	79
21	73	95	99	97	80
22	74	96	99	98	80
23	74	96	100	98	80
24	74	97	100	99	80
25	74	97	100	99	80
26	75	97	100	99	80
27	75	97	101	99	80
28	75	98	101	100	80

R= Replicate

Table 2: Validity criteria for OECD 301.

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%).	71% 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.	76% after 14 days	yes
The oxygen uptake of the inoculum blank is normally 20-30 mg O2/L and should not be greater than 60 mg/L in 28 days.	39.60 mg O2/L	yes

Validity criteria fulfilled:

yes

Remarks:

For further details please refer to table 2 in “Any other information on results incl. tables”.

Interpretation of results:

readily biodegradable

Description of key information

Readily biodegradable: 100% after 28 days (OECD 301F)

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

The ready biodegradability of Octan-1-ol, ethoxylated, < 2.5 EO was assessed in a study following OECD guideline 301 F. The O2 consumption of non-adapted activated sludge at a test material concentration of 100 mg/L was followed for 28 days. A degradation rate of 100% was reached after 28 days and the ten-day window criterion was met.

The substance is assessed as readily biodegradable according to OECD criteria.