Ethyltriphenylphosphonium acetate

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:

07 March 2018 - 04 April 2018

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.3110 (Ready Biodegradability)

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 (e.g. location, sampling depth, contamination history, procedure): A mixed population of sewage treatment micro-organisms was obtained on 5 March 2018 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 temperatures of between 20 and 21 ºC prior to use.

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: as recommended in the OECD Guidelines
- Additional substrate: no
- Solubilising agent (type and concentration if used): no
- Test temperature: between 21 and 23 ºC
- pH: 7.4
- pH adjusted: no
- Continuous darkness: diffuse light

TEST SYSTEM
- Culturing apparatus: 500 mL in 500 mL bottles
- Number of culture flasks/concentration: 3 (test item, inoculum blank), 2 (reference item, toxicity control)
- Measuring equipment: CES Multi-Channel Aerobic Respirometer
- Other: All vessels were inoculated with the prepared inoculum at a rate of 1% v/v.
The system consists of a sample flask sealed by a sensor head/CO2 trap immersed in a temperature controlled water bath. The samples were stirred for the duration of the test with a magnetically coupled stirrer.
As biodegradation progresses, the micro-organisms convert oxygen to carbon dioxide which is absorbed into the ethanolamine solution (50% v/v).

SAMPLING
- Sampling frequency: daily Biological Oxygen Demand (BOD) values

CONTROL AND BLANK SYSTEM
- Inoculum blank: Three replicate bottles containing inoculated mineral medium
- Reference item (procedural control): Two replicate bottles containing inoculated mineral medium and the reference item, aniline, at a concentration of 100 mg/L.
- Toxicity control: Two replicate bottles containing in inoculated mineral medium plus the reference item, aniline, at a concentration of 100 mg/L and the test item at a concentration of 100 mg/L

Reference substance:

aniline

Parameter:

% degradation (O2 consumption)

Value:

12

Sampling time:

28 d

Parameter:

% degradation (O2 consumption)

Remarks:

toxicity control

Value:

53

Sampling time:

14 d

Details on results:

The test item attained 12% biodegradation after 28 days, calculated from the oxygen consumption values, and therefore cannot be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No. 301F.
The toxicity control attained 53% biodegradation after 14 days and 56% biodegradation after 28 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 76% biodegradation after 14 days and 79% biodegradation after 28 days thereby confirming the suitability of the inoculum and test conditions.

Percentage Biodegradation Values

Day	% Biodegradation
	Procedure Control	Test Item			Toxicity Control
		Replicate 1	Replicate 2	Mean
0	0	0	0	0	0
1	0	0	0	0	0
2	1	8	7	8	3
3	1	10	10	10	4
4	16	11	11	11	6
5	38	12	12	12	20
6	55	12	12	12	37
7	62	12	12	12	46
8	69	13	12	13	49
9	72	13	12	13	50
10	74	13	12	13	50
11	75	13	12	13	51
12	75	13	12	13	52
13	76	13	12	13	52
14	76	13	12	13	53
15	76	13	12	13	53
16	77	13	12	13	53
17	77	13	12	13	54
18	77	13	12	13	54
19	77	13	12	13	54
20	78	13	12	13	55
21	78	13	12	13	55
22	78	13	12	13	55
23	78	12	11	12	55
24	78	12	11	12	55
25	78	12	11	12	56
26	78	12	11	12	56
27	79	12	11	12	56
28	79	12	11	12	56

Validation Criteria

The mean BOD of the inoculated mineral medium (control) was 28.24 mg O2/L after 28 days and therefore satisfied the validation criterion given in the OECD Test Guidelines.

The pH of the inoculated test item vessels on Day 28 were 7.9 and hence satisfied the validation criterion given in the OECD Test Guidelines.

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

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The test item attained 12% biodegradation after 28 days and therefore cannot be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No. 301F.

Executive summary:

This study was performed to assess the ready biodegradability of ETPPAAc in an aerobic aqueous media. The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (1992) No. 301F, “Ready Biodegradability; Manometric Respirometry Test” referenced as method C.4-D of Commission Regulation (EC) No. 440/2008 and US EPA Fate, Transport, and Transformation Test Guidelines OCSPP 835.3110 (Paragraph (q)).

The test item at a concentration of 100 mg/L was exposed to sewage treatment micro-organisms with mineral medium in sealed culture vessels in diffuse light at temperatures of between 21 and 23 ºC for 28 days.

The biodegradation of the test item was assessed by the measurement of daily oxygen consumption values on Days 0 to 28. Control solutions with inoculum and the reference item, aniline, together with a toxicity control were used for validation purposes.

The toxicity control attained 53% biodegradation after 14 days and 56% biodegradation after 28 days thereby confirming that the test item was not toxic to the sewage treatment micro-organisms used in the test.

Aniline (procedure control) attained 76% biodegradation after 14 days and 79% biodegradation after 28 days thereby confirming the suitability of the inoculum and test conditions.

The test item attained 12% biodegradation after 28 days and therefore cannot be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No. 301F.

Description of key information

12% degradation after 28 d (OECD TG 301F)

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater

Additional information

This study was performed to assess the ready biodegradability of ETPPAAc in an aerobic aqueous media. The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (1992) No. 301F, “Ready Biodegradability; Manometric Respirometry Test” referenced as method C.4-D of Commission Regulation (EC) No. 440/2008 and US EPA Fate, Transport, and Transformation Test Guidelines OCSPP 835.3110 (Paragraph (q)).

The test item at a concentration of 100 mg/L was exposed to sewage treatment micro-organisms with mineral medium in sealed culture vessels in diffuse light at temperatures of between 21 and 23 ºC for 28 days.

The biodegradation of the test item was assessed by the measurement of daily oxygen consumption values on Days 0 to 28. Control solutions with inoculum and the reference item, aniline, together with a toxicity control were used for validation purposes.

The toxicity control attained 53% biodegradation after 14 days and 56% biodegradation after 28 days thereby confirming that the test item was not toxic to the sewage treatment micro-organisms used in the test.

Aniline (procedure control) attained 76% biodegradation after 14 days and 79% biodegradation after 28 days thereby confirming the suitability of the inoculum and test conditions.

The test item attained 12% biodegradation after 28 days and therefore cannot be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No. 301F.