3,3'-(1,4-Phenylene)bis(5,6-diphenyl-1,2,4-triazine)

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study performed according to GLP and OECD 309 guideline.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

3-[4-(5,6-diphenyl-1,2,4-triazin-3-yl)phenyl]-5,6-diphenyl-1,2,4-triazine

EC Number:

700-823-1

Cas Number:

55514-22-2

Molecular formula:

C36H24N6

IUPAC Name:

3-[4-(5,6-diphenyl-1,2,4-triazin-3-yl)phenyl]-5,6-diphenyl-1,2,4-triazine

Details on test material:

- Name of test material (as cited in study report): CH0222 WP30
- Substance type: monoconstituent
- Physical state: powder
- Analytical purity: 99.8 %
- Purity test date: January 7th, 2012
- Lot/batch No.: LP140
- Stability under test conditions: stable at room temperature (20 +/- 5 °C) under dark and dry conditions
- Storage condition of test material: see above

Sampling and analysis

Analytical monitoring:

no

Test organisms

Test organisms (species):

activated sludge, domestic

Details on inoculum:

- Preparation of inoculum for exposure: The activated sludge was used as collected, but coarse particles were removed by sttling for 10 minutes ans then the upper layer decanted.
- Pretreatment: during holding prior to use the sludge was fe daily with 50 mL synthetic sewge (as described in OECD guideline) per litre and kept aerated at room temperature overnight.
- Initial biomass concentration: An aliquot of the final sludge suspension was weighed, dried and the ratio of wet sludge to its dry weight determined. Base on the skudge dry matter, xalculated amounts of wet sludge were suspended in tap water to yield a concentration equivalent to 2.5 g/L on dry weight basis. This level gave a concentration of 1.0 g/L suspended solid in the test medium.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Test conditions

Hardness:

Medium made up as required in OECD 309

Test temperature:

18 - 20 °C

pH:

7.2

Dissolved oxygen:

8.0 - 8.8 mg O2/L

Salinity:

freshwater

Nominal and measured concentrations:

100 mg/L nominal cocentration

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass flasks of approximately one litre volume
- Material, size, headspace, fill volume: 500 ml fill volume, flasks tightly capped during test
- Aeration: compressed air
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6
- Biomass loading rate: 200 mL activated sludge suspension / 500 mL

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: tap water

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: No

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :

Limit test at 100 mg/L nomibnal concentration (amount directly weighed in assay falsks due to poor water solubility)

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Results and discussion

Effect concentrations

Duration:

3 h

Dose descriptor:

EC0

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: No effect recorded

Results with reference substance (positive control):

- Results with reference substance: valid
- Relevant effect levels:
EC20 = 1.5 mg/L (95% cl 0.0 - 3.3 mg/L)
EC50 = 5.0 mg/L (95% cl 1.6 - 9.1 mg/L)

Reported statistics and error estimates:

Only for reference substance (refer to results 95% cl), but no effetc at all recorded for WP30.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 3hour EC10, EC20 and EC50 of WP30 were clearly higher than 100 mg/L. The NOEC was established to be also above 100 mg/L.

Executive summary:

The influence of WP30 on the activity of activated sludge was evaluated by measuring the respiration rate under conditions defined in the OECD 309 cguideline conditions. The repiration rate (oxygen consumption) of an aerobic activated sludge fed witha standar amount of synthetic sewage was measured in presence of 100 mg/L co,ce,tration of WP30 after a period of incubation of 3 hours.

WP30 was tested in triplicate, reference substance 3,5 -dichlorophenol in triplicate, and inoculum controls were made in 6 replicates.

WP30 was directly weighed into the test vessels. The respiration rates of the activated sludge treated with WP30 at a concentration of 100 mg/L differed by less than 10% from co,trol.

The positive control 3,5 -dichlorophenol was tested in the same way as WP30. The 3hour EC50 was found to be 5.0 mg/L thsu laying in the range of 2 - 25 mg/L recommended by the guideline. This result cofims the suitability of the activated sludge used.

Based on measured inhibition rates, the 3hour EC10, EC20 and EC50 f WP30 could not be quantified because at a nominal concentration of 100 mg/L, less than 10 % inhibition was observed after 3 hours incubation.

The NOEC of WP30 was therefore established to be above 100 mg/L.