Propan-2-yl N-[(S)-(pentafluorophenoxy)(phenoxy) phosphoryl]-L-alaninate

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:

23 October 2012-22 November 2012

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report date:

2013

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.3110 (Ready Biodegradability)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Propan-2-yl N-[(S)-(pentafluorophenoxy)(phenoxy)-phosphoryl]-L-alanine

EC Number:

695-076-0

Cas Number:

1334513-02-8

Molecular formula:

C18H17F5NO5P

IUPAC Name:

Propan-2-yl N-[(S)-(pentafluorophenoxy)(phenoxy)-phosphoryl]-L-alanine

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

Test item
- Name of test material (as cited in study report): GS-606962
- Substance type: organic
- Physical state: white powder
- Lot/batch No.: PSI-172(2)-1-1-12001
- Purity: 95.0-103.0%
- Storage condition of test material: room temperature in the dark

Reference item
Identification: Sodium benzoate
Description: white solid
Batch: MKBH2299V
Purity: 99%
Expiry/retest date: 26 June 2013
Storage consitions: room temperature over silica gel

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

10 other: mg carbon/L

Based on:

test mat.

Results and discussion

% Degradation

Parameter:

% degradation (CO2 evolution)

Value:

21

Sampling time:

28 d

Remarks on result:

other: pH = ca. 7.5 during 28 days test

Details on results:

The total CO2 evolution in the inoculum control vessels on Day 28 was 31.33 mg/L and therefore satisfied the validation criterion given in the OECD Test Guidelines.
The IC content of the test item suspension in the mineral medium at the start of the test was below 5% of the TC content and hence satisfied the validation criterion given in the OECD Test Guidelines.
The difference between the values for CO2 production at the end of the test for the replicate vessels was <20% and hence satisfied the validation criterion given in the OECD Test Guidelines.
Acidification of the test vessels on Day 28 followed by the final analysis on Day 29 was conducted according to the methods specified in the Test Guidelines. This acidification effectively kills the micro-organisms present and drives off any dissolved CO2 present in the test vessels. Therefore any additional CO2 detected in the Day 29 samples originated from dissolved CO2 that was present in the test vessels on Day 28 and hence the biodegradation value calculated from Day 29 analysis is taken as being the final biodegradation value for the test item.
The results of the inorganic carbon analysis of samples from the first absorber vessels on Day 29 showed a decrease in all replicate vessels with the exception of inoculum control replicate R2 and procedure control replicate R2. This decrease was considered due to sampling/analytical variation.
Inorganic carbon analysis of the samples from the second absorber vessels on Day 29 confirmed that no significant carry-over of CO2 into the second absorber vessel occurred.
The test item attained 21% degradation after 28 days and therefore cannot be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No. 301B.
The toxicity control attained 34% degradation after 14 days and 54% degradation after 28 days thereby confirming that the test item was not toxic to the sewage treatment micro-organism used in the test.
Sodium benzoate attained 101% degradation after 14 days and 109% degradation after 28 days thereby confirming the suitability of the inoculum and test conditions. Degradation values in excess of 100% were considered to be due to sampling/analytical variation.

Any other information on results incl. tables

Percentage Biodegradation Values

Day	% Degradation Sodium Benzoate Procedure Control	% Degradation Test Item	% Degradation Test Item plus Sodium Benzoate Toxicity Control
0	0	0	0
2	54	7	16
6	96	10	16
8	86	1	25
10	92	6	27
14	101	27	34
21	93	21	61
28	107	27	67
29*	109	21	54

*Day 29 values corrected to include any carry-over of CO2 detected in Absorber.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

other: not readily biodegradable under the strict terms and conditions of OECD Guideline No. 301B

Conclusions:

The test item attained 21% degradation after 28 days and therefore cannot be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No. 301B.

Executive summary:

Introduction

A study was performed to assess the ready biodegradability of the test item in an aerobic aqueous medium.

The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (1992) No. 301B "Ready Biodegradability; CO2 Evolution Test" referenced as Method C.4 -C of Commission Regulation (EC) No. 440/2008 and US EPA Fate, Transport, and Transformation TEST Guidelines OPPTS 835.3110.

Methods

The test item, at a concentration of 10 mg Carbon/L, was exposed to activated sewage sludge micro-organism with mineral medium is sealed culture vessels in the dark at 21 to 22°C for 28 days.

The degradation of the test item was assessed by the determination of carbon dioxide produced. Control solutions with inoculum and the reference item, sodium benzoate, together with a toxicity control were used for validation purposes.

Results

The test item attained 21% degradation after 28 days and therefore cannot be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No. 301B.