1,1-dimethylurea

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

September - December 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Qualifier:

according to guideline

Guideline:

other: The Guideline for the Testing of Chemicals 202, Daphnia sp. 24h EC50 Acute Immobilisation Test, MEP, China(2004).

GLP compliance:

yes

Remarks:

The study had been conducted in compliance with the following GLP principle: HJ/T 155-2004 The Guidelines of Chemical Testing Good Laboratory Practices. MEP. China.

Specific details on test material used for the study:

- Analytical purity: 99.9 %
- Lot/batch No.: 301601

Analytical monitoring:

yes

Details on sampling:

The concentration of the test substance was measured at the beginning of the test. At the end of the test the samples were analysed as a mixture which was collected in the same volume from each test vessel.

Vehicle:

no

Details on test solutions:

M4 medium (Batch No.:20131101-1) was used as test medium (composition and preparation similiar to OECD 202).

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Source: Reproduction in the test facility; Batch No.: DMT-20131105-1; This batch of the daphnids was borned within 17 hours, not the first brood progeny, and the age of them was less than 24 hours old at the start of exposure.
- Feeding during test: None

ACCLIMATION
- Acclimation period: The culture conditions of stock animals maintained was similar to those to be used in the test, so it was not domesticated prior to the start.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Post exposure observation period:

not applicable

Hardness:

185 mg/L(based as CaCO3)

Test temperature:

19.7-20.3 °C

pH:

7.66-7.94

Dissolved oxygen:

8.92-9.13 mg/L

Salinity:

not applicable

Nominal and measured concentrations:

Nominal concentration: 10 mg/L
Measured concentration after 0 hours: 100.1 mg/L
Measured concentration after 48 hours: 96.6 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 mL glass beaker (loosely covered to reduce the loss of water due to evaporation and to avoid the entry of dust to the solutions)
- No. of organisms per vessel: 5 daphnids
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: The water for preparation of the test medium was made by Purifying System (everse osmosis). The analysis results were archived in the archive room of Suzhou Xishan ZhongkeR&D Co., Ltd.
- Total organic carbon:

OTHER TEST CONDITIONS
- Photoperiod: 16 hours light and 8 hours dark

TEST CONCENTRATIONS
The immobility within the period of the test at the nominal concentration of 100 mg/L in the preliminary test was less than 10%. Therefore for the main test, one test concentrations was set as 100 mg/L of nominal concentration with four replicates.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Results with reference substance (positive control):

Commercially purchased potassium dichromate was used as the reference substance to determine the sensitivity of the test species and test condition. According to the sensitivity test (Study No.:2013-DE1-S02), the EC50(24 h) value was 1.1 mg/L.This fits the sensitivity requirement of 0.6-2.1 mg/L. The report and the raw data of the Sensitivity Study are archived in the archive room of the Suzhou Xishan Zhongke Drug R&D Co., Ltd. The reference test is performed at least twice every year.

Table 1: Total number of immobilised daphnids observed in the test

	Nominal Concentration of the test substance [mg/L]	Total number of daphnids	Total number of immobilised daphnids	Immobility [%]
Control group	0	20	0	0
Test group	100	20	0	0

Validity criteria fulfilled:

yes

Conclusions:

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.

Executive summary:

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 Guideline 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. Four replicates for each group were used, and every replicate contained five Daphnia magna. Each test vessel was checked for immobilized daphnids and any abnormal behavior or appearance at 24 and 48 hours after the beginning of the test.The analytical measurements of the concentration of the test substance in the test group were performed at the beginning and end of the exposure with HPLC. The average measured concentration in the test group was 100.1 mg/L (at the beginning of the test) and 96.6mg/L(after 48 hours after beginning of the test). Immobilised daphnids in the control and test group at 24 and 48 hours after the beginning of the test were not observed and there did not appear any abnormal behavior. Therefore the percentage of immobilized daphnids was 0% and 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.

Description of key information

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.

Additional information

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.