2-Propenoic acid, γ-ω-perfluoro-C8-14-alkyl esters

Biodegradation in water: screening tests

Description of key information

8:2 FTAC
The test item is classified as not readily biodegradable in the 10-d-window after 28 days.
8:2 FTOH
Inherently biodegradable: analytical measurement of two replicates demonstrated a degradation of 8-2 OH with concentrations of 42.0 and 41.9 µg/L on Day 0 decreasing to 37.4 and 8.3 µg/L on Day 7 and below the limit of detection on Day 14 (OECD 302B).
Anaerobic biodegradation in digested sludge: 42.7 % after 63 days (OECD 311)

Additional information

Readily biodegradation of 8:2 FTAc

The ready biodegradability of the test itemFluowet AC 800 was determined with a non adapted activated sludge over a test period of 28 days in the Headspace Test. Thestudy was conducted from 2012-12-19 to 2013-02-14, according to OECD 310 and EN ISO 14593 atDr.U.Noack-Laboratorien.The test item was tested at a concentration of35 mg/L in triplicates (test end: 5 replicates). To enhance the solubility of the test item in the test medium triethylene glycol dimethyl ether (triglyme) was used as solvent.The degradation of the test item was followed by specific analysis of the degradation products 8-2 FTOH, 8-2 FTUA, 8-2 FTA and PFOA by LC-MS/MS at test end (day 28). Furthermore the concentrations of the test item at test start and test end was determined by GC-MS analysis of the test medium. Additionally the headspace was sampled at test end to determine the volatile fraction of the test item in the test system.

 

The biodegradation of the reference item and toxicity control was followed by TIC analyses of the quantity of CO₂produced by the respiration of bacteria. The amount of TIC produced was calculated by correcting the results for endogenous TIC production of the solvent control groups and the blind value of the sodium hydroxide solution. The biodegradation was calculated for each sampling time.

 

To check the activity of the test system and the influence of the solvent aniline with addition of 1 % Triglyme was used asfunctional control. The percentage degradation of the functional control reached the pass level of 60 % after 14 days(Table1).

In the toxicity control, containing test and reference item and 1 % Triglyme, a biodegradation of 35 % was determined after 9 days and 14 days. The biodegradation of the reference item was not inhibited by the test item and Triglymein the toxicity control.(Table1).

Beyond day 14 until test end the calculated biodegradation decreases in the functional control and the toxicity control as the high TIC production by degradation of traces of the solvent Triglyme influenced the calculations. For details see4.2.1.

 

Table1:Biodegradation of the Functional Control and the Toxicity Control

	Biodegradation [%]
Day	1	9	14	21	28
Functional Control Reference Item + 1 % Triglyme	0	59	62	(52)	(25)
Toxicity Control, Test Item + Reference Item + 1 % Triglyme	0	35	35	(26)	(3)

               ( ) calculation of biodegradation influenced by traces of Triglyme

The biodegradation of thetest itemis given inTable2. The results of the specific test item analysis and the analytical results for the metabolites of the test item are summarized. The results indicate a slow biodegradation ofFluowet AC 800, a 8-2 fluortelomer methacrylate, under the test conditions. 2% 8-2 FTOH were formed within the 28 day test duration. Further relevant metabolites in the biotransformation of the test item were formed in amounts < 1%. 8-2-FTOH is expected to be the first transformation product after cleavage of the ester bond. Based on the knowledge about biotransformation of 8-2 FTOH an oxidation under formation of 8-2 FTA follows [Wang et al., 2009]. Further steps in the biotransformation include desaturation under formation of 8-2 FTuA and PFOA. The latter one represents a terminal product in the biotransformation cascade of 8-2 FTOH.

 

 

Table2:         Specific Test Item Analysis – Overview Results

Application concentration:     33.6 mg/LFluowetAC 800correspond to 100%,

                                                        

Sample Day	Matrix	Fluowet AC 800	8-2 FTOH	8-2 FTuA	8-2 FTA	PFOA
Day 0	MTBE Extract	100%	-	-	-	-
Day 28	MTBE Extract	89%	1%	< 1%	< 1%	< 1%
	Extracted              Test Medium	-	1%	< 1%	< 1%	< 1%
	Headspace	< 1%	< 1%	-	-	-

The test item is classified as
not readilybiodegradable

in the 10-d-window and after 28 days.

 

 

Read Across substance and main degradation product 8:2 FTOH

OECD 302B:

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One study on the inherent biodegradation potential of TRP-1989, including results on 8:2 FTOH (CAS No. 678-39-7), is available (Clariant GmbH, 2005). The test was conducted according to OECD Guideline 302B, under GLP conditions. The test item proper, i.e. TRP-1989, is a polymer (perfluoroalkyl acrylic copolymerisate). However, the biotransformation potential was monitored by analysing five residuals and potential transformation products, one of which is 8:2 FTOH (= 8-2 OH). Activated sludge microorganisms were exposed to the polymer at a concentration of 6000 mg/L for a period of 28 days. The biodegradation was followed by analytical measurement of 8:2 FTOH. Measurements of two replicates demonstrated a degradation of 8:2 FTOH with concentrations of 42.0 and 41.9 µg/L on Day 0 decreasing to 37.4 and 8.3 µg/L on Day 7 and below the limit of detection on Day 14. Thus 8:2 FTOH was eliminated/degraded to 100%. Due to the fact that 8:2 FTOH is highly volatile a volatility control was conducted in parallel and demonstrated that no test substance was lost.

OECD 311:

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One study on the anaerobic Biodegradability of Organic Compounds in Digested Sludge of 8-2 FTOH (CAS No. 678-39-7) is available (Clariant GmbH, 2007). The test is non-GLP but was conducted according to OECD Guideline 311. The biotransformation potential was monitored by analysing 3 potential transformation products: 8 COOH (PFOA), 8-2 COOH, 8-2 U COOH. Digested sludge was exposed to the test item concentration of 10 mg/L for a period of 63 days. The biodegradation was followed by analytical measurement of all analytes and parent substance. Measurements of three replicates demonstrated a degradation of 8:2 FTOH of 42.7% after 63 days. In the headspace gas no biotransformation products could be detected during the course of the study.

Two supporting studies regarding OECD Guideline 301D and 301C shows that the 8:2 FTOH is not readily biodegradable.