bis(2-ethylhexyl) 4,4’-{6-[4-tert-butylcarbamoyl)anilino]-1,3,5-triazine-2,4-diyldiimino}dibenzoate

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

421-450-8

EC Name:

-

Cas Number:

154702-15-5

Molecular formula:

C44H59N7O5

IUPAC Name:

2-ethylhexyl 4-[(4-{[4-(tert-butylcarbamoyl)phenyl]amino}-6-[(4-{[(2-ethylhexyl)oxy]carbonyl}phenyl)amino]-1,3,5-triazin-2-yl)amino]benzoate

Details on test material:

- Name of test material (as cited in study report): Uvasorb HEB
- Physical state: off white powder
- Lot/batch No.: 1508G21
- Storage condition of test material: room temperature in the dark

Test organisms

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

A mixed population of activated sewage sludge micro-organisms was obtained for the range-finding test and for the definitive test from the aeration stage of the Severn Trent Water Plc sewage treatment plant at Loughborough, Leicestershire, UK .

Study design

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Test conditions

Hardness:

Laboratory tap water dechlorinated
140 mg/l as CaCO3

Test temperature:

about 21 °C

pH:

8.1 at the start of the experiment
8.5 at the end of the experiment

Reference substance (positive control):

yes

Remarks:

3.5 -dichlorophenol

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Effect concentrations 2

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

1 000 mg/L

Nominal / measured:

nominal

Any other information on results incl. tables

Range-finding Test

No significant effect on respiration wa observed at either test concentration employed. Based on this information, a single test concentration, in triplicate, of 1000 mg/l was selected for the definitive test.The test material was insoluble in water and it was justifiable to conduct the definitive test at a single concentration of 1000 mg/l in excess of the water solubility level of the test material.

Definitive test

It was considered unnecessary and unrealistic to test at concentrations in excess of 1000 mg/l.

The initial and final dissolved oxygen concentrations wwere below those recommended in the test guidelines (6.5 and 2.5 mg O2/l respectively). This was considered to have had no adverse effect on the results of the study given that in all cases the oxygen consumption rate was determined over the linear portion of the oxygen consumption trace.

The validation criteria for the control respiration rates have been satisfied.

Observations made showed that at the test concentration of 1000 mg/l at 0 hours and 30 mins contact time there was a dark brown dispersion with particles of test material on the surface and dispersed throughout. a pale brown dispersion with particles of test material dispersed homogenously throughout was observed at 3 hours contact time.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The effect of the test material on the respiration of activated sewage sludge micro-organisms gave a 3-h EC50 of greater than 1000 mg/l. The NOEC after 3 h exposure was 1000 mg/l.