Reaction product of: 2,4-diamino-6-[2-(2-methyl-1H-imidazol-1-yl)ethyl]-1,3,5-triazine and cyanuric acid

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:

18 May - 07 Jul 2006

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2006

Report date:

2006

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

1992

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.3110 (Ready Biodegradability)

Version / remarks:

1998

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

The Department of Health of the Government of the United Kingdom

Test material

Test material information

Constituent 1

Study design

Oxygen conditions:

aerobic

Remarks:

CO2-free air

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Worlingworth sewage treatment works treating predominantly domestic waste
- Initial cell/biomass concentration: 30 mg/L suspended solids concentration

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

10 mg/L

Based on:

other: Carbon

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: Mineral salts medium according to guideline
- Test temperature: 20.1 - 24.0 °C
- pH: 7.5 - 7.6
- pH adjusted: No
- Aeration of dilution water: Air-saturated ultrapure water was used to prepare the mineral salts medium.
- Suspended solids concentration: 30 mg/L

TEST SYSTEM
- Culturing apparatus: 5 L vessels
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: Aeration with CO2-free air (air was passed through cylinders containing fused calcium chloride and Carbosorb AS)
- Details of trap for CO2 and volatile organics if used: 3 Dreschel bottles in series, connected to the outlets of every test vessels, each containing barium hydroxide

SAMPLING
- Sampling frequency: Day 2, 4, 6, 7, 8, 11, 14, 21, 28, 29
- Other: 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 phenolphthalein indicator. Following the removal of the first Dreschel bottle in the series of 3, the second was connected to the test vessel and the bottle containing fresh barium hydroxide was connected to the outlet of the bottle at the end of the series. On Day 28 of the test, titrations were performed and then concentrated hydrochloric acid (1 mL) was added to each vessel to drive off dissolved organic carbon. The contents of the vessels were aerated overnight and the final titrations were carried out on Day 29.

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2 replicates (mineral salts medium + inoculum)
- Reference compound: 1 replicate (mineral salts medium + inoculum + 10 mg C/L sodium benzoate)
- Toxicity control: 1 replicate (mineral salts medium + inoculum + 10 mg C/L sodium benzoate + 10 mg C/L test item)

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

% Degradation

% Degradation 1

Parameter:

% degradation (CO2 evolution)

Value:

0

Sampling time:

28 d

% Degradation 2

Parameter:

% degradation (CO2 evolution)

Value:

0

Sampling time:

29 d

Details on results:

The cumulative CO2 production of the vessels containing the test item was negligible by the end of the test on Day 29.
The degradation of the reference compound sodium benzoate was rapid and reached 62% of its ThCO2 after 7 d and 77% after 29 d.
The degradation of the reference compound was also rapid in the presence of the test item and reached 65% of its ThCO2 after 7 d.

Any other information on results incl. tables

VALIDITY CRITERIA

The inoculum and toxicity controls confirmed the suitability of the test and inoculum.

The study fulfills the validity criteria of this test (Table 1).

 

Table 1: Validity criteria for OECD 301 B.

Criterion from the guideline	Outcome	Validity criterion fulfilled
Difference of extremes of replicate values of the removal of the test chemical at the plateau, at the end of the test or at the end of the 10-d window, as appropriate, is less than 20%.	The difference of extremes was < 20%.	Yes
Percentage degradation of the reference compound has reached the pass levels by day 14.	Percentage degradation of the reference compound is 71% on Day 14.	Yes
The toxicity control should degrade to at least 35% (based on DOC) or at least 25% (based on ThOD or ThCO2) within 14 d.	The toxicity control degraded by 65% on Day 7.	Yes
The IC content of the test substance suspension in the mineral medium at the beginning of the test must be less than 5% of the TC.	data not reported
The total CO2 evolution in the inoculum blank at the end of the test should not normally exceed 40 mg/L medium.	data not reported

 

Applicant's summary and conclusion

Interpretation of results:

under test conditions no biodegradation observed