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Ecotoxicological information

Sediment toxicity

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Administrative data

Endpoint:
sediment toxicity: short-term
Type of information:
experimental study
Adequacy of study:
key study
Study period:
16/02/2000 - 04/07/2000
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP, not a Guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2000
Report Date:
2000

Materials and methods

Test guideline
Qualifier:
no guideline available
Principles of method if other than guideline:
The 48-hour acute toxicity of dinotefuran to the first instar larvae of the midge Chironomus riparius was studied under static conditions for 48 hours. Larvae were exposed to the test item at nominal concentrations of 100, 46, 22, 10, 4.6, 2.2 µg/L and a blank control (0 µg/L).
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: solid

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
0 and 48 hours, stored at ~-20°C

Test substrate

Vehicle:
no
Details on sediment and application:
Not applicable

Test organisms

Test organisms (species):
Chironomus riparius
Details on test organisms:
Species/strain: Chironomus riparius
Age: First instar larvae, 2-3 days old
Breeding method: Not described
Kind of food: Green alga/TetraMin® fish food : 1/1 contributing 5 mg carbon /L test solution
Amount of food: Contributing 5 mg carbon /L test solution (as TOC)
Feeding frequency: Before start of exposure
Pretreatment: Not applicable
Feeding of animals during test: None

Study design

Study type:
laboratory study
Test type:
static
Water media type:
freshwater
Type of sediment:
not specified
Limit test:
no
Exposure duration
Duration:
48 h
Exposure phase:
total exposure duration
Post exposure observation period:
None

Test conditions

Hardness:
2.5 mmol/L (of dilution water)
Test temperature:
20°C
pH:
7.9- 8.0
Dissolved oxygen:
8.8 mg/L
Salinity:
Not applicable
Ammonia:
Not reported
Nominal and measured concentrations:
See table below:Nominal and measured concentrations
Details on test conditions:
Type of test: Acute 48 hour toxicity
Renewal of test solution: No
Volume of test vessels: 100 mL
Amount/volume of sediment per vessel: None
Volume of test medium per vessel: 50 mL
Volume/animal: 10 mL
Number of animals/vessel: 5
Number of vessels/ concentration: 4
Test performed in closed vessels due to significant volatility of TS: No
Quality/Intensity of irradiation: Light intensity 300 – 700 lux
Photoperiod: 16 hours light / 8 hours dark
Reference substance (positive control):
no

Results and discussion

Effect concentrationsopen allclose all
Key result
Duration:
48 h
Dose descriptor:
LC0
Effect conc.:
46 µg/L
Basis for effect:
mortality
Remarks:
and sublethal effects
Key result
Duration:
48 h
Dose descriptor:
LC50
Effect conc.:
72.1 µg/L
Basis for effect:
mortality
Remarks:
and sublethal effects
Key result
Duration:
48 h
Dose descriptor:
LC100
Effect conc.:
100 µg/L
Basis for effect:
mortality
Remarks:
and sublethal effects
Key result
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
22 µg/L
Basis for effect:
mortality
Remarks:
and sublethal effects
Key result
Duration:
48 h
Dose descriptor:
LOEC
Effect conc.:
46 µg/L
Basis for effect:
mortality
Remarks:
and sublethal effects
Details on results:
The analytical determined concentrations of dinotefuran in the analysed test media from the start and the end of the exposure period ranged from 92 – 98 % of the nominal concentrations. Therefore biological results are based on nominal concentrations.

After 24 hours no mortality was determined in the control or at any concentration tested. However at 100 µg/L, all larvae showed convulsions and unusual body movements.

After 48 hours 17 of 20 larvae exposed to 100 µg/L test item concentration were dead and surviving larvae showed sublethal effects like convulsions and unusual body movements. Larvae in the 46 µg/L test item concentration showed the same sublethal effect as in the 100 µg/L dose level.
The 48 hour LC50 was calculated to be 72.1 µg/L with 95 % confidence limits of 64.5 and 80.6 µg/L. The 48 hour NOEC was determined to be 22 µg/L and the 48 hour LOEC was 46 µg/L.

All test media appeared as clear solution throughout the exposure period.

See Table 1.
Results with reference substance (positive control):
Not applicable
Reported statistics and error estimates:
The survival of the larvae or symtoms of intoxication were determined by means of a binocular after 24 and 48 hours of exposure. The 48-hour LC50 and the 95% confidence limits were calculated by Moving Average Interpolation. The 24-hour LC50 of the test item could not be calculated because none of the larvae were dead at that time. The NOEC, LOEC, LC0 and LC100 were determined directly from the raw data without any data transformation.

Any other information on results incl. tables

Nominal and measured concentrations:

Nominal test concentration [µg/L]

Sample

[h]

Measured Concentration

[µg/L]

100

0

94

48

92

46

0

43

48

43

22

0

22

48

22

Control

0

< LOD

48

< LOD

Only samples ≥ 48 hour NOEC were analysed

Table 1:    Mortality of larvae ofChironomus ripariusafter 48 hours of exposure

Nominal test item concentration [μg/L]

No. of larvae tested

No. dead larvae after 24 hours

No. dead larvae after 48 hours

Mortality after 24 hours

[%]

Mortality after 48 hours

[%]

0

20

0

0

0

0

2.2

20

0

0

0

0

4.6

20

0

0

0

0

10

20

0

0

0

0

22

20

0

0

0

0

46

20

0

0*

0

0

100

20

0*

17**

0

85

*   all larvae showing sublethal effects, e.g. convulsion, unusual body movements

** surviving larvae showing sublethal effects, e.g. convulsion, unusual body movements

 

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
Validity criteria of the combined guidelines are fulfilled. A clear dose response of the test item for survival could be determined.
The 48 hour LC50 was calculated to be 72.1 µg/L with 95 % confidence limits of 64.5 and 80.6 µg/L. The 48 hour NOEC was determined to be 22 µg/L and the 48 hour LOEC was 46 µg/L.