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Administrative data

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:
no hazard identified

Marine water

Hazard assessment conclusion:
no hazard identified

STP

Hazard assessment conclusion:
no hazard identified

Sediment (freshwater)

Hazard assessment conclusion:
no hazard identified

Sediment (marine water)

Hazard assessment conclusion:
no hazard identified

Hazard for air

Air

Hazard assessment conclusion:
no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:
no hazard identified

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:
no potential for bioaccumulation

Additional information

Conclusive experimental results are available for fish, invertebrates (daphnia), algae and microorganism. No effects were observed for the test substance 1,1-Dimethylurea up to the highest test concentrations:

The acute toxicity effects of the test substance 1,1-Dimethylurea was tested on Zebra-fish with an exposure time of 96 hours. The study was under static conditions according to the guideline OECD 203. The mortality was 0 % and no visible abnormalitiesin the control and treated group during the test period were observed. The measured concentrations of test substance were 102.21 mg/L and 106.56 mg/L at the start and the end of the test respectively. The LC50 (96h) value of 1,1-dimethylurea on Zebra-fish species was greater than 100 mg/L based on nominal concentration.

The toxicity of 1,1-Dimethylurea on Daphnia magna was tested in a 48 hour acute immobilisation test. The test was performed static according to OECD 202 ("Daphnia sp., Acute Immobilisation Test") with with one test group (the nominal concentration of the test substance was 100 mg/L) and one control group.

The EC50 (48 h) value of test substance 1,1-dimethylurea on daphnia sp. was greater than 100 mg/L nominal concentration under the test conditions of this study.

To evalute the effects of 1,1 -Dimethylurea on growth and reproduction of an unicellular freshwater algae species a study according to OECD Guideline 201 ("Alga, Growth Inhibition Test") was performed. Only one limit concentration with 100 mg/L and one control group were designed for the definitve test according to the result of the preliminary test. The growth inhibition rates (%Ir) of 1,1 -Dimethylurea on Pseudokirchneriella subcapitata were -4.79 - 3.50 %, the average value was -1.57 %. The percent inhibiton in yield (%Iy) was -16.86 - 10.93 %, the average value was -5 .55 %. So the EC50(72 h) was greater than 100 mg/L which was calculated as nominal concentration.

The influence of 1,1 -Dimethylurea on the respiration rate of activated sludge was investigated in a study accorrding EU Method C.11 ("Biodegradation: Activated Sludge Respiration Inhibition Test"). Under the conditions of this present test, the EC20(3h)-, EC50(3h)- and EC80(3h)-value of 1,1 -Dimethylurea were higher than 1000 mg/L which was calculated as nominal concentration based on measured inhibition rates.

Conclusion on classification

Conclusive experimental results are available for fish, invertebrates (daphnia), algae and microorganism. No effects were observed up to the highest test concentrations:

The LC50 (96h) value of test substance 1,1-dimethylurea on Zebra-fish species was greater than 100 mg/L based on nominal concentration under the test conditions in this study. Due to the results of a test according to OECD 202, the EC50 (48 h) value of test substance 1,1-dimethylurea on daphnia sp. was greater than 100 mg/L nominal concentration. The EC50 (72h) of test substance 1,1-Dimethylurea on Pseudokirchneriella subcapitata was greater than 100 mg/L which was calculated as nominal concentration under the test conditions of this study. Under the conditions of a present test on the respiration rate of activated sludge, the EC20(3h)-, EC50(3h)-, EC80(3h)-value of 1,1-dimethylurea were higher than 1000 mg/L which was calculated as nominal concentration based on measured inhibition rates.

Furthermore 1,1-Dimethylurea is readily biodegradable and has a low potential for bioaccumulation. In conclusion no classification according to GHS Regulation EC No 1272/2008 for acute or chronic aquatic toxicity is required.