5-nitro-2,4,6-triaminopyrimidine

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)

Rationale for reliability incl. deficiencies:

other: GLP guideline study according OECD 209

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

yes

Remarks:

; Exceeding the test temperature range of 20 ± 2 °C with 0.2°C. An influence to the results of this study can be excluded.

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

; Exceeding the test temperature range of 20 ± 2 °C with 0.2°C. An influence to the results of this study can be excluded.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

5-nitro-2,4,6-triaminopyrimidine

EC Number:

213-742-7

EC Name:

5-nitro-2,4,6-triaminopyrimidine

Cas Number:

1006-23-1

Molecular formula:

C4 H6 N6 O

IUPAC Name:

5-nitropyrimidine-2,4,6-triamine

Details on test material:

- Physical state: Solid/ pink to red
- Storage condition of test material: Ambient at room temperature

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Details on test solutions:

- Application of the test substance: Direct addition by initial weight into the test flasks. The test substance was weighed in the required amounts for the test concentrations directly to the test vessels.

Test organisms

Test organisms (species):

activated sludge, domestic

Details on inoculum:

Test system: municipal Activated sludge
Reason for the selection of the test system: required by the test guidelines
Age: 1 day
Origin: aeration tank of the wastewater treatment plant of Mannheim, Germany
Collection of the test system: 14 Jan 2015
Arrival in the test facility: 14 Jan 2015
After arrival of the activated sludge suspension in the test facility the suspension was sieved with a fine woven mesh (mesh size about 1 mm). This suspension was pre-aerated over night at room temperature. At the next day the sludge suspension was washed once with drinking water and the suspension was adjusted to 3 g/L Dw.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test conditions

Test temperature:

21.3 - 22.2 °C

pH:

7.4 - 7.5

Dissolved oxygen:

Oxygen concentration during aeration: > 2 mg/L
Oxygen concentration immediately before measurement: > 7 mg/L

Nominal and measured concentrations:

1000, 500, 250, 125, 62.5 mg/L as nominal concentration based on test substance and blank controls.
100, 10, 1 mg/L as nominal concentration based on reference substance.

Details on test conditions:

TEST SYSTEM
- Test vessel: Glas-beakers (nominal volume 1L)
- Test volume: 500 mL
- Sludge concentration in the test vessel: 1.5 g/L Dw
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6
- No. of vessels per each reference substance (replicates): 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: 16 mL/test vessel of 100-fold concentrated OECD medium

OTHER TEST CONDITIONS
- Adjustment of pH: no

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :

TEST CONCENTRATIONS
- Spacing factor for test concentrations: According to the test guidelines, at least 5 concentrations in a geometric series with a separation factor of ≤ 3.2 should be used, preferably encompassing the range from 10 – 80% inhibition.

Reference substance (positive control):

yes

Remarks:

3,5 dichlorophenol

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

> 1 000 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:

other: EC20

Effect conc.:

> 1 000 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:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Effect concentrations 4

Duration:

3 h

Dose descriptor:

other: EC80

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

Validity criteria:
The coefficient of variation of the six replicates of blank control was 3.6 % O2 consumption.
The EC50 of 3,5-dichlorophenol was 8.6 mg/L
The mean oxygen uptake of the blank controls was 22 mg/g*h
In conclusion, the test conformed to all validity criteria and is valid.

Results with reference substance (positive control):

In order to verify that the microorganisms are responding normally to toxic stress, tests with a reference substance are conducted according to OECD 209 guideline. The results from the reference substance test are compared to EC50 values published in OECD 209 guideline, which represent the typical response range.
According to the test guideline OECD 209 the EC50 values of the reference substance 3,5-dichlorophenol should be in the range of 2-25 mg/L after 3 hours of incubation.
The EC50 of the reference substance 3,5-dichlorophenol was in the range of 2-25 mg/L in 3 hours.
These results indicate that the microorganisms are responding normally to toxicant stress.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

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