5,5-Dimethylimidazolidine-2,4-dione, reaction products with oxirane

Endpoint summary

Description of key information

Short-term and long-term aquatic toxicity studies are available for Dantocol DHE and no toxicity was observed at the highest concentration tested in all studies. The studies fulfill the data requirements for the aquatic toxicity endpoints and no further testing is required.

Three reliable short-term toxicity studies in fish (Klimisch 1) are available for the test substance. Studies with rainbow trout (Onchorhynchus mykiss) and zebra fish (Danio rerio) reported 96-hour LC50 values of >100 mg/L based on nominal test concentrations of Dantocol DHE (Goodband and Mullee (2007) and Zhao (2007), respectively). A prolonged toxicity study in zebra fish (Danio rerio) was conducted on a semi-static basis over 14 days. The study was run at the single nominal test concentration of 100 mg/L with test substance renewal every 48 hours. The 14-day NOEC (mortality) was 100 mg/L based on nominal test concentrations. The results of all three studies are consistent and demonstrate that the test substance does not cause significant acute toxicity to freshwater fish over a prolonged time period. Additionally, no other signs of toxicity were observed to fish (including observations of toxicity and changes to weight and length) during an extended acute 14 day test.

The short-term toxicity of Dantocol DHE to aquatic invertebrates (Daphnia magna) was estimated according to the internationally accepted test guideline OECD 202 and to GLP. After 48-hours the EC50 was determined to be >100 mg/L (nominal). The long-term toxicity study was conducted using the aquatic invertebrateDaphnia magnaat a range of concentrations up to 100 mg/L (nominal). After 21-days the NOEC was determined to be 100 mg/L (nominal). These studies demonstrate that Dantocol DHE does not cause significant short-term or long-term toxicity to aquatic invertebrates.

There is one reliable (Klimisch 1) long-term toxicity study with aquatic freshwater algae (Desmodesmus subspicatusis) available for the test substance. The study was conducted to OECD 201 test guideline and according to GLP (SafePharm Laboratories, 2007). The 72-hour EC50 and NOEC (growth rate and yield) were determined to be 100 mg/L based on nominal test concentrations. This study result demonstrates that the test substance does not cause significant toxicity to freshwater algae, under the conditions of the test.

Short-term toxicity studies are available for fish, invertebrates and algae and long-term toxicity studies are available for invertebrates and algae and no toxicity was observed at the highest concentration tested in all of the short- and long-term studies. It is anticipated that toxicity would be unlikely to be observed in a long-term fish test based on the absence of toxicity observed in other aquatic toxicity tests. The long-term fish toxicity test is waived and no further testing is proposed.