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

Bioaccumulation: aquatic / sediment

Administrative data

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1980/11 to 1980/12

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1980

Materials and methods

Test guideline

Qualifier:

no guideline followed

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

Radiolabelling:

yes

Remarks:

triazine-ring-labelled 14C-cyromazine (5.5 millcuries; specific activity of 50.3 microcuries per milligram, µCi/mg)

Sampling and analysis

Details on sampling:

Water samples were taken on days 0, 3, 7, 10, 14, 21 and 28 of exposure and 1, 3, 7, 10 and 14 of depuration. Four fish were removed from each treatment aquarium, eviscerated and filleted on days 1, 3, 7, 10, 14, 21 and 28 of exposure and days 1, 3, 7, 10 and 14 of depuration and the residues in edible, non-edible and thus also whole fish parts determined. Samples were pooled frozen and homogenized before three aliquots per treatment day were selected for radiometric analysis. The samples were combusted with the resultant 14CO2 being trapped in scintillation fluid, which was placed into a scintillation vial, in a scintillation counter and the counts per minute was determined.

Test solutions

Vehicle:

yes

Remarks:

Methanol

Details on preparation of test solutions, spiked fish food or sediment:

The treatment aquarium (unit 1) was filled with diluent water (75 L) and spiked with 5.16 mL of the 14.53 mg/mL cyromazine diluter stock. The resulting solution was vigorously stirred to achieve homogeneity.

Test organisms

Test organisms (species):

Lepomis macrochirus

Details on test organisms:

150 bluegill sunfish with a mean wet weight of 2.5 g and a standard length of 5.7 cm

Study design

Route of exposure:

aqueous

Justification for method:

aqueous exposure method used for following reason: Standard methodology for bioconcentration determination

Test type:

flow-through

Water / sediment media type:

natural water

Total exposure / uptake duration:

28 d

Total depuration duration:

7 d

Test conditions

Test temperature:

22 ± 1.0 °C :

For the static test:
21.0 ± 1.0°C

pH:

for main test 5-7
: For static test 6-7

Dissolved oxygen:

60 % saturation (5.3 mg/mL)

Details on test conditions:

The test chambers consisted of a 170 L glass aquarium containing 75 litres of water (treatment chamber) and a 54-litre aquarium containing approximately 30 litres of water (control chamber). The flow through system was calibrated such that the treatment aquarium had a turnover rate of 3 volumes per day, whilst the smaller control aquarium had a turnover rate of seven volumes per day. As the water flowed into the aquaria either the radioactive test treatment or the methanol (solvent) control was added via a chemical induction system.

Nominal and measured concentrations:

1.0 mg/mL

Results and discussion

Details on results:

The maximum accumulation of 14C-residues in the edible portion (muscle) of the fish occurred on day three of exposure. After day three the rate of elimination was far greater than the rate of accumulation. Based on a mean maximum concentration of 0.67 ± 0.021 µg/g measured in the edible tissue for day 3 and a mean concentration of 0.93 ± 0.22 µg/mL 14C-cyromazine measured in the water during day 0-3 of exposure, the mean bioconcentration factor of 14C-cyromazine in bluegill edible tissue was less than 1x.

In non-edible tissues (viscera-carcass) the concentration of 14C-cyromazine in continuously exposed tissue occurred during the first day of exposure. Based on the mean concentrations of 2.1 ± 0 1 µg/g measured in non-edible tissues (day 1) and mean exposure concentration of 0.84 ± 0.23 µg/mL (days 0-1), the maximum bioconcentration factor for 14C-cyromazine in the non-edible bluegill tissues was 2.5x. Following a continuous decrease of 14C-residues from the non-edible tissue 1-14 days of exposure from days 14-28 an apparent period of equilibrium was established. Therefore, the mean equilibrium bioconcentration factor for 14C-cyromazine observed throughout the observation period was less than 1 in the non-edible bluegill tissues. Analyses were also performed to estimate the total 14C-residue content on a whole fish basis.

The maximum bioconcentration factor for 14C-cyromazine for the whole fish was less than 1. The level of 14C-cyromazine in edible fish portions was below detectable levels throughout the depuration phase. The half-life of 14C-residues in the edible tissue occurred during exposure days 3-7. For non-edible tissues 14C-residues were below the limit of detection by day 10 of the depuration phase. The half-life for 14C-residues in non-edible tissues occurred between days 3 and 7 of depuration. The whole body 14C-residues were below the limit of detection throughout the depuration phase and was directly related to the lack of measurable concentrations in the edible portions


As in the 3-d flow-through exposure period the maximum accumulation of 14C residues in bluegill exposed to 14C-cyromazine for 28-days occurred within the first 3-days, it was necessary to re-initiate the dynamic flow-through to obtain fish for us in the the static exposure test. The dynamic flow-through system was re-employed for 3-days to obtain fish for use in the 4-day static exposure test although the aqueous 14C-concentrations were equivalent to those in the flow-through system the actual measured 14C residues in the tissues were only 24-30% of those, which had been previously observed in this main 28-day exposure test.
During the 4-day static exposure, fish exhibited normal behaviour and were in good condition The mean water temperature was 21 ± 1°C, the dissolved oxygen concentration ranged from 4.0-8.6 mg/L (44-96% of saturation) during the test with the pH being 6.6-7.1
The bioconcentration factors in the muscle, viscera, carcass and whole body were all less than 1.

Any other information on results incl. tables

Table 1

 

Measured ¹⁴C-residue concentrations of cyromazine in tissues of bluegill sunfish during exposure for 28 days under flow-through conditions (1.0 mg cyromazine/L) followed by 14-day depuration phase

Period	Day	Measured water conc (µg/mL)^a	^14C-residue concentrations (µ  /g)
			Edible ^b	Non-edible ^b	Whole fish ^c
Exposure	0	1.0 (0.058)	-	-
	1	1.1 (0)	< 0.18 ^d	2.1	<0.62 ^e
	3	1.1 (0)	0.67	0.72	0.70
	7	1.1 (0)	< 0.15 ^d	0.51	< 0.29 ^e
	10	1.0 (0.058)	0.12	0.44	0.26
	14	1.0 (0.058)	0.081	0.27	0.15
	21	1.0 (0)	< 0.20 ^d	0.34	< 0.25 ^e
	28	1.0 (0.058)	< 0.17 ^d	0.35	< 0.24 ^e
Depuration	1	0.019 (0.0049)	< 0.26 ^d	0.38	<0.31 ^e
	3	0.023 (0.0061)	< 0.23 ^d	0.21	<0.22 ^e
	7	0.011 (0.0058)	< 0.14 ^d	0.16	< 0.15 ^d
	10	<0.0078 ^d	<0.15 ^d	< 0.28 ^d	< 0.21 ^d
	14	0.0098	<0.19 ^d	< 0.17 ^d	< 0.17 ^d

^a Mean and standard deviation based on radiometric analysis of triplicate water samples

^b Mean and standard deviation based on the radiometric analysis of triplicate samples of the pooled tissue homogenate from four fish

^c Concentration based on the summation of the mean measured concentration of ¹⁴C-residues from each tissue portion and the total weight of the tissue portion from four fish

^d Concentration below minimum detectable levels

^e Concentration of one portion below minimum detectable levels

 

 

Table 2

 

Measured ¹⁴C-residue concentrations of cyromazine in fish tissues after 4-days of static exposure

Mean measured conc (µg/mL)	^14C-residue concentrations (µg/g)
Water	Muscle	Viscera	Carcass	Whole body
1 3 ± 0 045	0.057 (0.0015)	0.10 (0.00058)	0.15 (0)	0.090 (-)

Standard deviation in brackets

Applicant's summary and conclusion

Validity criteria fulfilled:

not applicable

Conclusions:

Data generated in the flow-through and static test systems 14C-cyromazine shows no potential to bio- accumulate in bluegill sunfish. The mean equilibrium bioconcentration factor for 14C-cyromazine observed throughout the observation period was less than 1.

Executive summary:

The objective of this investigation was to define the kinetics of the uptake and elimination of cyromazine, an experimental insect growth inhibititor, including its degradation products and metabolites by bluegill sunfish, in a dynamic flow thorugh system. Bluegill sunfish were continously exposed to a mean measured concentration of 1.0 ± 0.14 μg/mL cyromazine in well water for 28 days after which the remaining fish transferred to flowing, uncontaminated water for a 14 depuration period. Based on mean maximum concentrations in the edible tissue for day 3 and the mean concentration measured in the water during day 0-3 of exposure, the mean bioconcentration factor of 14C-cyromazine in bluegill edible tissue was less than 1x. The maximum bioconcentration factor for 14C-cyromazine in the non-edible bluegill tissues was 2.5x. The mean equilibrium bioconcentration factor for 14C-cyromazine observed throughout the observation period was less than 1 in the non-edible bluegill tissues. The maximum bioconcentration factor for 14C-cyromazine for the whole fish was less than 1. The level of 14C-cyromazine in edible fish portions was below detectable levels throughout the depuration phase. The half-life for 14C-residues in non-edible tissues occurred between days 3 and 7 of depuration. The whole body 14C-residues were below the limit of detection throughout the depuration phase and was directly related to the lack of measurable concentrations in the edible portions.

 

A 4-day static test was also performed for the purpose of determining the metabolism of cyromazine by bluegill sunfish. The test duration was based on the accumulation, persistence and elimination of cyromazine observed in the 28-day exposure test. The bioconcentration factors in the muscle, viscera, carcass and whole body were all less than 1.