(1,4,5,6-tetrahydro-4,6-dioxopyrimidin-2-yl)cyanamide

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

From 11th to 22nd November 1991.

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Version / remarks:

A new version of the guidance was published after release of the study report.

GLP compliance:

not specified

Specific details on test material used for the study:

Test material: CYDI ((1,4,5,6-Tetrahydro-4,6-dioxopyrimidin-2-yl)cyanamide)
Description: Off-white powder
Storage: In original container at room temperature
Molecular formula: C5H4N4O2

Analytical monitoring:

no

Vehicle:

yes

Remarks:

Preliminary solution in 1% Tween 80-dimethylsulphoxide

Details on test solutions:

10 mg/L was the highest test concentration that could be prepared due to the limited solubility of the test material in water and auxiliary solvent and having due regard to the amount of auxiliary solvent permitted in the test under the OECD Guidelines. Other combinations of the various recognised auxiliary solvents and mixtures of Tween 80 (up to 20% Tween 80 in solvent) were used during the range-finding experiment, however the comb'ination of 1% Tween 80-dimethylsulphoxide was found to give the best testable dispersion of the test material in water. At higher test concentrations there was a marked precipitation of the test material on addition of the solvent stock solution to water.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

Test species: Rainbow trout (Oncorhynchus mykiss).
Length: 4.6 ± 0.2 cm.
Weight: 1.28 ± 0.28 g (Loading: 0.64g bodyweight/litre).
Supplier: Parkwood Trout Farm, Kent, U.K.
Mortalities: Zero in the seven days prior to the start of the test.
Medication: None.

Test type:

not specified

Water media type:

freshwater

Remarks:

Dechlorinated tap water

Limit test:

no

Total exposure duration:

96 h

Hardness:

Approximately 50 mg/l as CaCO3

Test temperature:

14°C

pH:

Not specified.

Dissolved oxygen:

Not specified.

Salinity:

Not specified.

Conductivity:

Not specified.

Nominal and measured concentrations:

Nominal concentrations: 0.1, 1 and 10 mg/L.

Details on test conditions:

Tes vessels: 20L.
Aeration: Yes.

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 10 mg/L

Details on results:

No mortality was observed at any of the tested concentrations (0.1, 1 and 10 mg/L) during the preliminary range-finding study.
2 replicates of the highest tested concentration (10 mg/L) were then performed. No mortality was observed.

Sublethal observations / clinical signs:

Table 1: Results of the preliminary range-finding test

Concentration (mg/L)	Cumulative Mortality (initial population = 2)
	24 Hours	48 Hours	72 Hours	96 Hours
Control	0	0	0	0
Solvent Control	0	0	0	0
0.10	0	0	0	0
1.0	0	0	0	0
10	0	0	0	0

Table 2: Results of the mortality study on the highest test substance concentration

Concentration (mg/1 )	Cumulative	Mortality (initial population = 10)
	24 hours	48 Hours	72 Hours	96 Hours
Control	0	0	0	0
Solvent Control	0	0	0	0
10 R1	0	0	0	0
10 R2	0	0	0	0

R1 = first repetition; R2= second repetition

Validity criteria fulfilled:

not specified

Conclusions:

The LC50 of (1,4,5,6-Tetrahydro-4,6-dioxopyrimidin-2-yl)cyanamide could not be determined as no mortality was observed at any tested concentration during the study.

The LC50 of (1,4,5,6-Tetrahydro-4,6-dioxopyrimidin-2-yl)cyanamide was therefored determined to be > 10mg/L for 96h exposure.

Executive summary:

The acute toxicity to fish (Oncorhynchus mykiss) of CYDI ((1,4,5,6-Tetrahydro-4,6-dioxopyrimidin-2-yl)cyanamide) was evaluated.

The results indicate that none of the tested concentrations (0.1, 1 and 10 mg/L) in test substance cause mortality to fish after 96 hours exposure.

The LC_50,96h of (1,4,5,6-Tetrahydro-4,6-dioxopyrimidin-2-yl)cyanamide to fish was therefore determined to be > 10mg/L.

This result indicates that (1,4,5,6-Tetrahydro-4,6-dioxopyrimidin-2-yl)cyanamide should not be classified for Aquatic Acute Toxicity according to CLP ( Regulation (EC) No 1272/2008 on classification, labelling and packaging (CLP) of substances and mixtures).

Description of key information

The acute toxicity to fish (Oncorhynchus mykiss) of CYDI ((1,4,5,6-Tetrahydro-4,6-dioxopyrimidin-2-yl)cyanamide) was evaluated.

The results indicate that none of the tested concentrations (0.1, 1 and 10 mg/L) in test substance cause mortality to fish after 96 hours exposure.

The LC_50,96hof (1,4,5,6-Tetrahydro-4,6-dioxopyrimidin-2-yl)cyanamide to fish was therefore determined to be > 10mg/L.

This result indicates that (1,4,5,6-Tetrahydro-4,6-dioxopyrimidin-2-yl)cyanamide should not be classified for Aquatic Acute Toxicity according to CLP ( Regulation (EC) No 1272/2008 on classification, labelling and packaging (CLP) of substances and mixtures).

The value of 10mg/L is mentionned to be the solubility limit of the test item and no death was observed so no LC50 value higher than 10 mg/L can be derived, meaning that (1,4,5,6-Tetrahydro-4,6-dioxopyrimidin-2-yl)cyanamide should not be classified for Aquatic Chronic Toxicity according to CLP.