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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Additional information

Acute toxicity

Some data regarding short-term toxicity to invertebrates and to fish are reported in HSDB Report of 1,3-Dichloro-5,5-dimethylhydantoin with reference to USEPA, Office of Pesticide Programs; Pesticide Ecotoxicity Database (2000) on 1,3-Dichloro-5,5-dimethyl-2,4-imidazolidinedione (118-52-5). No data are available regarding to aquatic algae and cyanobacteria.

All data are reported in the specific summary and in this generic summary only the lowest values are indicated:

- LC50 Oncorhynchus mykiss (Rainbow trout, juvenile) 96h= 0.58 ppm equivalent to 0.58 mg/l

- EC50 Daphnia magna 48h = 0.47 ppm equivalent to 0.47 mg/l

Based on these values of short term toxicity to invertebrates and to fish the classification H400 (acute aquatic hazard, cat.1) is proposed for DCDMH according to the CLP Regulation (EC n.1272/2008).


Chronic toxicity

No data are available regarding long-term toxicity of 1,3-Dichloro-5,5-dimethylhydantoin.

As reported in the document Halohydantoins RED, EPA 739-R-07-001, September 2007 generic dihalodialkylhydantoin has been shown to hydrolyze relatively rapidly (under abiotic conditions half-lives of less than 30 days in pH 5, pH 7, and pH 9). The major degradate, dimethylhydantoin (DMH ), was hydrolytically stable but , as reported always in the document of EPA, DMH demonstrates low toxicity to terrestrial and aquatic animals (for major details regarding the data see table p.38 of the document Halohydantoins RED, EPA 739-R-07-001, September 2007).

Moreover in database ECOTOX-EPA for the research with CAS 118-52-5 (1,3-dichloro-5,5-dimethylhydantoin) some long-term aquatic toxicity data for CAS 16079-88-2 (1-bromo-3-chloro-5,5-dimethylhydantoin) were reported. This association was done by EPA probably due to the similarity of the two substances (same structure but different halogen in position 1). Based on data reported in database ECOTOX-EPA with reference to Pesticide Ecotoxicity Database (1992) for 1-bromo-3-chloro-5,5-dimethylhydantoin NOEC Daphnia magna 21 days = 70.9 mg/l and NOEC Pimephales promelas 33 days= 14 mg/l.

Based on data available for major metabolite and for a similar substance (1,3-dichloro-5,5-dimethylhydantoin) no classification for chronic aquatic toxicity is proposed for DCDMH according to the CLP Regulation (EC n.1272/2008).