Tributyl-2-methoxypropylphosphonium salt with 4,4'-[2,2,2-trifluoro-1-(trifluoromethyl)ethylidene]bis[phenol]

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:

22 June 2005-21 July 2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study conducted under GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2005

Report date:

2005

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

ISO DIS 9439 (Ultimate Aerobic Biodegradability - Method by Analysis of Released Carbon Dioxide)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

126049-00-1

Cas Number:

126049-00-1

IUPAC Name:

126049-00-1

Constituent 2

Reference substance name:

MTDID 3285

IUPAC Name:

MTDID 3285

Details on test material:

- Name of test material (as cited in study report): MTDID 3285
- Analytical purity: min 80%
- Stability under test conditions: Stable
- Storage condition of test material: At room temperature in the dark

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, predominantly domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Activated sludge from the "Waterschap de Maaskant', 's-Hertogenbosch, The Netherlands, municipal sewage treatment plant.
- Storage conditions: Continuous aeration until use.
- Storage length: Not reported ("freshly obtained")
- Preparation of inoculum for exposure: Sludge allowed to settle 33 minutes and liquid decanted for use as inoculum.
- Pretreatment: None
- Concentration of sludge: 4.9 g suspended solids /L in concentrated sludge

Duration of test (contact time):

>= 28 d

Initial test substance concentration

Initial conc.:

ca. 40 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: Standard mineral media as per OECD 301B. Aerated with synthetic air (21% oxygen, 79% nitrogen, <1 ppm CO2) overnight to purge the media of CO2.
- Test temperature: 21.6 - 22.3 deg C
- pH: 7.5 - 7.6
- pH adjusted: Yes (1 N HCl)
- Aeration of dilution water: Dilution water not aerated separately
- Suspended solids concentration: 49 mg/L (Concentrated sludge diluted 10 mL/L mineral medium.)
- Continuous darkness: Not reported. Test vessels were brown-colored bottles
- Other: Test media aerated and stirred continuously during the test period.

TEST SYSTEM
- Culturing apparatus: 2-liter all-glass brown colored bottles
- Number of culture flasks/concentration: 2 for test suspension; 2 for inoculum blank, 1 for reference substance, 1 for toxicity control.
- Method used to create aerobic conditions: Continuous aeration and stirring. Synthetic air was passed through 0.0125M barium hydroxide to remove any CO2 present prior to use to aerate the test system. Synthetic air was sparged through scrubbing solution at a rate of ca. 30-100 mL/min.
- Measuring equipment: CO2 production determined by titrating remaining barium hydroxide with 0.05 M standardized HCl
- Test performed in open system: yes (CO2-free synthetic air blown continuously through medium)
- Details of trap for CO2 and volatile organics if used: 100 mL of 0.0125 M Ba(OH)2) in each of three bottles connected in series to the exit air line of each exposure flask.
- Other: Test substance was not sufficiently water soluble to allow preparation of an aqueous stock solution. Weighed amounts of test substance and then 10 mL of Milli-RO water were added to weighing bottles. The weighing bottles were vigorously mixed (by vortex) and the resulting suspension was added quantitatively to the test bottles. The test solutions were continuously stirred during the test to ensure optimal contact between the test substance and the microorganisms.

SAMPLING
- Sampling frequency: Every second or third day during the first 10 days and thereafter at least every fifth day until the 28th day for the inoculum blank and test suspension.
- Sampling method: At each sample time, the CO2 absorber nearest to the test bottle was removed for analysis. Each of the remaining two absorbers was moved one position in the direction of the test bottle and a new absorber was placed at the far end of the series. Phenolphthalein was used as a pH indicator. On the 28th day, the pH of all test solutions was measured and 1 mL of 37% HCl was added to each bottle. The bottles were aerated overnight to drive off any CO2 present. The final titrations were made on day 29.
- Sample storage before analysis: None.
- Other: The theoretical CO2 production was calculated from the molecular formula.

CONTROL AND BLANK SYSTEM
- Inoculum blank: Contained only mineral media and inoculum
- Abiotic sterile control: None
- Toxicity control: Contained test substance at ca. 40 mg/L and sodium acetate at 40 mg/L plus mineral medium and inoculum

Reference substance

Reference substance:

acetic acid, sodium salt

Results and discussion

Preliminary study:

Not applicable

% Degradation

Parameter:

% degradation (CO2 evolution)

Value:

>= 1 - <= 15

Sampling time:

28 d

Remarks on result:

other: Mean degradation, 8%

Details on results:

-The ThCO2 of MTDID 3285 was calculated to be 2.20 mg CO2/mg based on structure.
The ThCO2 of sodium acetate was calculated to be 1.07 mg CO2/mg based on structure.

The test substance has no inorganic carbon content. Test substance in mineral medium has < 5% of total carbon as inorganic carbon.

CO2 evolution in blanks was within limits of OECD TG301B (Table 2).

CO2 evolution for the reference substance was within the 10-day window and reached 101% by Day 27 (Table 3).

CO2 evolution in the toxicity control was 35% of ThCO2 (Table 6) on day 14. No inhibition by MTDID 3285 is expected.

% biodegradation vs time plot - see Figure 1

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

> 60% degradation for reference substance; difference in biodegradation between duplicate flasks less than 20% ; inorganic carbon content of test substance in mineral medium < 5% of the total carbon content; total CO2 evolution in blank < 40 mg/L

Interpretation of results:

other: Not really biodegradable

Conclusions:

MTDID 3285 was not readily biodegradable under test conditions

Executive summary:

The ready biodegradability of MTDID 3285 was studied in a 28-day CO2 evolution test according to OECD method 301B. Activated sludge from a domestic sewage treatment plant was used as the source of inoculum. Brown glass bottles were filled with oxygen-saturated, CO2-free medium and spiked with one of the following: MTDID 3285 at ca. 20 mg/L (12 mg TOC/L), sodium acetate (reference substance) at 40 mg/L (12 mg TOC/L), MTDID 3285 plus sodium acetate (toxicity control), or inoculum alone (inoculum blank). Evolved CO2 was titrated every second or third day during the first 10 days and thereafter at least every fifth day until the 28th day. The 28-day biodegradation of MTDID 3285 was found to be 1% or 15% (mean, 8%) in the two test bottles by CO2 evolution. In the toxicity control 35% biodegradation occurred within 14 days, therefore the test substance did not inhibit microbial activity. The reference substance sodium acetate showed 104% biodegradation at 28 days demonstrating the viability of the inoculum. Based on these data, MTDID 3285 was found to not be readily biodegradable under the conditions of the CO2 evolution test.

This study is classified as acceptable and satisfies the guideline requirements for test method OECD301B, ready biodegradability: CO2 evolution test.

Results Synopsis

Percent degradability: 8% 95% C.I.: not applicable