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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Ecotoxicological information

Endpoint summary

Administrative data

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 LC50,96hof (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.

However, considering the the not rapidely biodegradability of the test item and 96h LC50 for fish >10 mg/L, it is classified as Aquatic chronic 3 according to CLP.

Additional information

Respiration inhibition of (1,4,5,6-tetrahydro-4,6-dioxopyrimidin-2-yl)cyanamide on activated sludge has been studied. The activated sludge was subjected to various concentrations of test substance for 3 consecutive hours.

A preliminary study has been carried out with test substance concentrations of 1, 10, 100 and 1000 mg/L.

Based on the results obtained in this preliminary test, it was decided to make new measurements on 100 mg/L replicates.

The average respiration inhibition based on the 100 mg/L replicates was found to be 4%.

The EC50 for respiration inhibition of activated sludge by (1,4,5,6-tetrahydro-4,6-dioxopyrimidin-2-yl)cyanamide after 3 hours of exposure was therefore determined to be > 100 mg/L.