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

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

29-Oct--2002 to 27-Nov-2002

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP compliant; Guideline Study (OECD 209)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Report date:

2003

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Version / remarks:

1992

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)

Version / remarks:

1988

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

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method:
The dilution water used to prepare solutions of synthetic sewage and the reference substance was tap water that had been softened and treated by reverse osmosis (Elgastat Prima 4, reverse osmosis unit, Vivendi Water Systems) and then purified (Elgastat UHP unit, Vivendi Water Systems) to give a resistivity >18 MegOhm.cm. This water complies with the relevant standards (British Standard (BS) 3978, 1987; American Society for Testing and Materials (ASTM) D 1193-99) for classification as Grade 1 or Type 1 water for laboratory use.

Test organisms

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Laboratory culture:
A sample of activated sludge was obtained the day before the start of the test from Oakley Sewage Treatment Works, which treats predominantly domestic waste. In the laboratory, the sample was maintained under aerobic conditions until required.
- Pretreatment:
On the day of collection, aliquots (25 mL) of the activated sludge were filtered through dried and preweighed Whatman GFC filter papers which were then dried again at approximately 105°C for at least one hour, allowed to cool in a desiccator and reweighed. The mixed liquor suspended solids (MLSS) content of the activated sludge was then calculated and adjusted to 4 g/1 by the removal of supernatant.
- Initial biomass concentration: 50 mL/L. The concentration of suspended solids in a homogenised sample was determined on the day of collection and immediately before the start of the test.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test conditions

Hardness:

200-250 mg/L

Test temperature:

Initial: 19.9 - 20.7 °C
Final: 18.7 - 20.2 °C

pH:

Initial: 7.5 - 7.9
Final: 7.9 - 8.2

Dissolved oxygen:

27.8 - 29.2 mg/g/h

Nominal and measured concentrations:

Nominal: 1, 10, 100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: beakers
-fill volume: 500 mL
- Aeration: for 3 hours using a Pasteur pipette connected to a laboratory supply of oil-free compressed air (1L/min)
- No. of vessels per concentration (replicates): 1 and 10 mg/L: 1; 100 mg/L: 3
- No. of vessels per control (replicates): 2

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Following the exposure period, a well-mixed sample of each mixture was transferred to a biochemical oxygen demand (BOD) bottle (capacity; 270 ml). The rate of oxygen consumption was measured, over a period of approximately ten minutes or until the dissolved oxygen concentration fell below 2 mg/l, using a Yellow Springs Instruments (YSI) dissolved oxygen meter, with temperature probe and self-stirring bottle probe, connected to a chart recorder.

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

3 h

Dose descriptor:

other: EC20

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Effect concentrations 2

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Effect concentrations 3

Duration:

3 h

Dose descriptor:

other: EC80

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Results with reference substance (positive control):

- Results with reference substance valid? YES
The three-hour EC50 for 3,5-DCP (10.5 mg/L) fulfilled the validity criterion relating to sensitivity to inhibition (acceptable EC50 range 5 to 30 mg/L), and that relating to the respiration rates in the control (variation not greater than 15%) was also satisfied.

Any other information on results incl. tables

The test item had no inhibitory effect on the respiration rate of activated sludge at any of the concentrations employed in the test. Sludge respiration rates were decreased, at most, by 7% of the mean control rate at 10 mg/l. The EC20, EC50 and EC80 of the test substance could not, therefore, be calculated but these must be greater than 100 mg/l, the highest level tested.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The inhibition of the degradation activity of activated sludge is not anticipated when introduced in appropriate low concentrations.