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Short-term toxicity to fish

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Reference
Endpoint:
short-term toxicity to fish
Type of information:
experimental study
Adequacy of study:
key study
Study period:
September - October 2013
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 203 (Fish, Acute Toxicity Test)
Qualifier:
according to guideline
Guideline:
other: The Guideline for the Testing of Chemicals 203, Fish Acute Toxicity Test. MEP. China.2004
GLP compliance:
yes
Remarks:
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 concentrations of test solutions were measured at the start and the end of the exposure. 1mL samples were taken from threereplicatesin each treated group and injected to analyze concentration.
Vehicle:
no
Details on test solutions:
To prepare the stock solution of 1000 mg/L (nominal concentration), 1.0004 g of the test substance were dissolved in the test water and the solution was made up to 1000mL under stirring. Then 300 mL stock solution of the test substance were added and diluted to 3000mL with test water to prepare the test solution for 3 replicates. 3000mL test water was added into each test vessel of the control group. The solutions were prepared for one time and just before use.
Test organisms (species):
Danio rerio (previous name: Brachydanio rerio)
Details on test organisms:
TEST ORGANISM
- Common name: Zebra-fish (Brachydanio rerio)
- Strain: EK (Ekkwill)
- Source: Aquality Technology (501Nanhu Avenue, Wuxi City, Jiangsu Province, China)
- Feedingt: Fish were fed daily until 24 hours before the test was started.
- Food type: Fairy shrimp eggs were purchased from the United States Inve Aquaculture inc. The eggs were hatched to larva as the food for fish.

ACCLIMATION
- Acclimation period: 7 days
- Acclimation conditions (same as test or not): acclimation conditions were in the same range as in the test.

Only fish were selected for the test which do not have disease and visible deformities.
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
96 h
Post exposure observation period:
Not applicable
Hardness:
40 mg CaCO3/L
Test temperature:
22.4-23.6 °C
pH:
6.83-7.45
Dissolved oxygen:
68.3%-98.6% air saturation value
Salinity:
Not applicalbe
Nominal and measured concentrations:
nominal concentration: 100 mg/L
measured concentration at the start of the exposure: 102.21
measured concentration at the end of the exposure: 106.56
Reference substance (positive control):
yes
Remarks:
potassium dichromate
Key result
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality (fish)
Details on results:
Mortalities and abnormalities:
The mortality during the acclimatization period was 0 %. During the test period, the mortalities were 0 % and no visible abnormalitieswere found in each group.

Body length and body weight:
The body length of test fish was within the range of 2.300-2.980 cm, which meet the requirement of 2.0±1.0 cm in the test Guidelines.The maximum loading was 0.680 g fish/litre during the test.
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-FE1-S03, study date was from 2013-07-04 to 2013-07-12), the LC50 (24 h) of potassium dichromate to Zebra-fish was 216 mg/L. This value is within the range of 200 mg/L to 400 mg/L, which meets the validity requirements of the sensitivity of the test species and test condition. The report and the raw data of the sensitivity study were archived in the archive room of the Suzhou XishanZhongke Drug R&D Co., Ltd.
Validity criteria fulfilled:
yes
Conclusions:
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.
Executive summary:

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.

According to the result of the preliminary test, one treated group (nominal concentration was 100 mg/L) and control group were designed in the definitive test. Each group consisted of three replicates with 7 fish in each replicate. The fish were observed at 3, 6, 24, 48, 72 and 96 hours after the start of the exposure. The concentrations of the test substance in the treated group were analyzed at the start and the end of exposure with HPLC.

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.

Description of key information

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.

Key value for chemical safety assessment

Additional information

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.