N-cyclopropyl-1,3,5-triazine-2,4,6-triamine

Phototransformation in water

Administrative data

Endpoint:

phototransformation in water

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2003/05/22 to 2003/07/25

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2003

Report date:

2003

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: JMAFF Guideline, 12 Nohsan 8147

Version / remarks:

2000

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

N-cyclopropyl-1,3,5-triazine-2,4,6-triamine

EC Number:

266-257-8

EC Name:

N-cyclopropyl-1,3,5-triazine-2,4,6-triamine

Cas Number:

66215-27-8

Molecular formula:

C6H10N6

IUPAC Name:

N2-cyclopropyl-1,3,5-triazine-2,4,6-triamine

Test material form:

solid: particulate/powder

Study design

Analytical method:

high-performance liquid chromatography

other:

Details on sampling:

Duplicate irradiated and single dark control samples were removed after 0, 1, 3, 5, 8 10, 12 and 15 days and 0, 1, 3, 8 and 15 days of continuous irradiation/incubation.

Light source:

Xenon lamp

Light spectrum: wavelength in nm:

290 - < 800

Details on light source:

Xenon Burner: Max. 765 W/m2 at max. UV filtering (lambda < 800 nm) with controllable irradiance between 400 W/m2 and 765 W/m2 to a pre— set value.

Filters: UV filter with a 290 nm cut-off to simulate natural sunlight.
Exposure Area: Approximately 500 cm2
Light Intensity: Determined with a LI-1800 spectrophotometer (44 W/m2)
Reaction Vessel Area: 3.5 cm2 the test vessels were positioned in the centre of the irradiated area.
The spectral energy distribution of the Xenon burner measured through the borosilicate glass
lids and of the sun, measured from 300 to 800 nm

Details on test conditions:

The test item was exposed to light in 25 ml incubation tubes (inner diameter 2.1 cm, height 11.0 cm, exposed area 3.5 cm2) constructed entirely of glass (see Figure 1) and covered with borosilicate lids which absorbs radiation below 290 nm similarly to the natural sunlight cut—off by ozone. The solutions were continuously illuminated through their borosilicate lids and stirred using magnetic stirrers.

Filtered, humidified air was drawn through the incubation vessels over the solutions at about 10 mL/minute. Any radioactive carbon dioxide or organic volatiles in the purged air was captured in traps of ethylene glycol followed by 2M NaOH, respectively. In addition to the irradiated samples, individual aliquots of 15 ml sterilized pond water were incubated under identical conditions in the dark using the same vessels as for the irradiated solution (dark control).

Duration of test at given test condition

Duration:

15 d

Temp.:

26 °C

Initial conc. measured:

1.761 mg/L

Reference substance:

no

Results and discussion

% Degradation

% Degradation 1

Key result

Test condition:

Irradiated

% Degradation 2

Test condition:

Dark covered soil

% Degradation 3

Test condition:

Non-extractables were observed in the 0 h samples ranging from 7 % in the moist to 13 % in the dry soil, whereas the corresponding amounts of Cyromazine were 93 and 86 %.

% Degradation 4

Test condition:

After 24 hours of exposure, the moist covered and exposed soil samples contained 68 and 71 % of CGA 72 662, respectively. The corresponding values for the dry soil samples were found to be 72 and 78 %, respectively .

Transformation products:

no

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The results clearly showed that no significant photodegradation of Cyromazine in sterilised natural pond water.

Executive summary:

The photochemical degradation of cyromazine was investigated under simulated sunlight in sterilised natural pond water at pH 8.7. Simulated sunlight from a “Suntest” apparatus equipped with a 1.8 kW xenon arc lamp, withfilters to remove wave lengths below 290 nm, was used to irradiate individual samples of cyromazine in sterile pond water at an initial concentration of 1.761 mg/L and maintained at a mean temperature of 26.0 ± 0.6°C.

 

The intensity of the lamp was slightly higher (44.6 than that of natural daylight (37.6 W/m²) measured at the same time in the spring with the same spectrophotometer at RCC Ltd. facility, 47.5°N latitude. The irradiation was for a continuous period of 15 days. Control samples were incubated under the same conditions but in the dark. Samples were taken for analysis at intervals up to 15 days with radiochemical quantification by liquid scintillation counting (LSC) and chromatographic analysis by high performance liquid chromatography (HPLC) and/or thin layer chromatography (TLC).

 

The total mean recoveries from the irradiated and dark control samples were 102.0% ± 2.2% and 103.3% ± 2.9% of the applied radioactivity, respectively, during the 15 day irradiation/incubation period. Under irradiated conditions, no significant photodegradation of cyromazine was observed. At the end of irradiation (day 15), cyromazine still accounted for 95.0% of the applied radioactivity (all percentages are given as mean values of replicates) with the samples showing no significant trend for degradation. For these reasons no degradation rates could be calculated for the test item and the DT 50 value was estimated to be > 100 “Suntest” days.

 

 Since the experimental photolytic half life DT50 was estimated to be > 100 days under the “Suntest” artificial light conditions, the corresponding environmental photolytic half lives (DT50) at different latitudes (30°N to 50°N and for Tokyo, 35°N) were also estimated to be higher than 100 days (by a factor 3.0, 3.2, and 5.7 for 30-40 N, 50°N and Tokyo 35 °N respectively).

 

Up to four minor radioactive fractions were detected of which one (M1), was characterised as Melamin by co-chromatography with the unlabelled reference compound using HPLC and TLC analysis. M1 increased to a maximum of 2.4% of the applied radioactivity on day 15. The other photodegradates reached amounts up to 1.4% of the applied radioactivity (M4, day 1). Mineralisation of cyromazine was negligible throughout the irradiation period, with radioactive carbon dioxide never exceeding 0.1% of the applied radioactivity throughout the study. Cyromazine was stable in the dark control samples indicating that there was no hydrolysis during the study (102.1 % at day 15). The results therefore, showed that no significant photodegradation of cyromazine occurred in sterilised natural pond water.