Propanoic acid, 2-[4-[4,6-bis([1,1'-biphenyl]-4-yl)-1,3,5-triazin-2-yl]-3-hydroxyphenoxy]-, isooctyl ester

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-Oct-2002 to 22-Nov-2002

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study (OECD test guideline 301B)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2003

Report date:

2003

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

adopted on 17th July 1992

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

adopted on 29th December 1992

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.3110 (Ready Biodegradability)

Version / remarks:

adopted in April 1996

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

444-090-3

EC Name:

-

Cas Number:

204848-45-3

Molecular formula:

C44 H43 N3 O4

IUPAC Name:

Propanoic acid, 2-[4-[4,6-bis([1,1'-biphenyl]-4-yl)-1,3,5-triazin-2-yl]-3-hydroxyphenoxy]-, isooctyl ester

Details on test material:

- Appearance: yellow powder

Study design

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): Oakley, sewage treatment works
- Pretreatment: Aliquots (25 mL) of a homgenised sample were filtered through dried and pre-weighed filter papers. The filters were dried for one hour, allowed to cool and re-weighed.
- Initial cell/biomass concentration: 30 mg/L
- Type and size of filter used, if any: Whatman GF/C

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

10.5 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: Prepared according to the method described in the guideline
- Test temperature: 20.4 - 22.6 °C
- pH: 7.5 -7.6
- Suspended solids concentration: inoculate control: 30 mg/L
- Air flow: 30 - 75 mL/minute

TEST SYSTEM
- Culturing apparatus: five-litre amber glass culture bottles equiped with an air inlet tube and a magnetic stirrer
- Number of culture flasks/concentration: 5 flasks comtaining 10.5 mgC/L
- Method used to create aerobic conditions: treated air to remove CO2 by passing it through cylinders containing fused calcium chloride, Carbosorb AS and a trap containing 1 M sodium hydroxide solution
- Measuring equipment:
- Test performed in closed vessels due to significant volatility of test substance: Each vessel was fitted with a stopper. The air outlet from each vessel was conntected to three Dreschel bottels in series, each containing 0.025 N nominal barium hydroxide (100 mL). The residual concentrations of barium hydroxide in the bottles nearest to the test vessels were determined at intervals by duplicate titration of 20 mL samples with hydrochloric acid (0.05 N), using phenolphthaleine indicator. Following the removal of the first Dreschel bottle in a series, the second was connected to the test vessel, and a bottle containing fresh barium hydroxide was connected to the outlet of the bottle at the end of the series.

SAMPLING
- Sampling method:
Test, control and reference mixtures were aerated for 29 days with air that had been treated to remove carbon dioxide (CO2). The CO2 produced by each culture was trapped in a series of Dreschel bottles containing barium hydroxide, which were connected to the outlet from each test vessel. The residual barium hydroxide was determined at intervals by titration.

CONTROL AND BLANK SYSTEM
- Two control vessels contained inoculated mineral salts medium alone and one contained inoculated mineral salts medium plus the reference substance sodium benzoate (10 mgC/L). An additional mixture containing sodium benzoate (10 mgC/L) and the test item (10.5 mgC/L) was established in order to assess the potential inhibitory effects of the test substance on the activity of the microbial inoculum.
- Inoculum blank: yes (mineral salts medium plus incolum (30 mg solids/L))

Reference substance

Reference substance:

other: inoculated mineral salts medium plus sodium benzoate

Results and discussion

Preliminary study:

The results of preliminary solubility trials performed before the biodegradability test showed that the test item was insufficiently soluble to allow the preparation of an aqueous stock solution.

Test performance:

Air-saturated ultrapure water was added to each of six, five-litre amber glass culture bottles followed by the volumes of each of the stock solutions required to prepare three litres of mineral salts medium. Each culture bottle was then inoculated with activated sludge (30 mg solids/L) and a magnetic stirring bar was added. The bottles were stoppered, their contents were mixed by swirling then each was placed on an electrically-operated magnetic stirrer. The mixtures were aerated overnight with a supply of air that had been treated to remove carbon dioxide by passing it through cylinders containing fused calcium chloride, Carbosorb AS and a trap containing 1M sodium hydroxide solution.
The results of preliminary solubility trials performed before the biodegradability test showed that the test item was insufficiently soluble to allow the preparation of an aqueous stock solution. Therefore, at test initiation on Day 0, aqueous mixtures (nominally 40.5 mg/50 ml) were prepared in ultrapure water, treated with ultrasound for 30 minutes then added to culture bottles. Each preparation flask was rinsed with three 50 ml portions of ultrapure water and these rinses were also added to the respective culture bottle.
The reference substance sodium benzoate was added as an aqueous stock solution (1.72 g/1) to one bottle containing the test substance and to one containing inoculated mineral salts medium alone.
Ultrapure water (200 ml) was also added to the control cultures on Day 0 of the test in order to ensure similarity in volume additions to those containing the test substance.

% Degradation

Parameter:

% degradation (CO2 evolution)

Value:

4

Sampling time:

28 d

Details on results:

Substances are considered to be readily biodegradable in this test if CO2 production is equal to or greater than 60% of the theoretical value within ten days of the level achieving 10%. Therefore, the test item cannot be considered to be readily biodegradable.

BOD5 / COD results

Results with reference substance:

Sodium benzoate had been biodegraded by 64% after 6 days and 90% after 29 days in the absence of the test item and by 64% after 6 days in its presence, which confirmed that the test item was not inhibitory to the activity of the microbial inoculum. Cumulative levels of CO2 production in the controls after 29 days (58.9 and 57.8 mg CO2) were within the acceptable range for this assay system (recommended maximum =120 mgCO2 for a three-litre culture). These results confirm that the inoculum was viable and that the test was valid.

Any other information on results incl. tables

The carbon content was calculated from information on the consumption and empirical formula of constituents that was available at the time of study conduct. Further information concerning the composition of the test item was provided after the test was performed. As the results of elemental analysis gave a definitive level of carbon, this was used to calculate the level of test substance (as carbon) added to the test cultures. The recalculated value (equivalent to 10.5 mg as carbon/L) differed slightly from the level originally determined and the intended concentration specified, but was within the acceptable range (10-20 mgC/L). Therefore, this was not considered significant.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The test substance is not readily biodegradable according OECD criteria.