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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
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
Analytical monitoring:
yes
Details on sampling:
0 and 48 hours, stored at ~-20°C
Vehicle:
no
Details on sediment and application:
Not applicable
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 type:
laboratory study
Test type:
static
Water media type:
freshwater
Type of sediment:
not specified
Limit test:
no
Duration:
48 h
Exposure phase:
total exposure duration
Post exposure observation period:
None
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
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.

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

 

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.
Endpoint:
sediment toxicity: long-term
Type of information:
experimental study
Adequacy of study:
key study
Study period:
11/10/2002 - 10/12/2003
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP, Guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 219 (Sediment-Water Chironomid Toxicity Test Using Spiked Water)
Deviations:
no
GLP compliance:
yes
Analytical monitoring:
yes
Details on sampling:
• 2 samples each of every application solution immediately after application
• Sediment, pore water and overlaying water samples from the 8 and 32 µg/L treatment were taken on day 0, 7 and 27
• Sediment, pore water and overlaying water samples from the control (0 µg/L) were taken on days 0 and 27
• All samples were stored frozen at ~-20°C immediately after sampling until analysis
Vehicle:
no
Details on sediment and application:
Type/source: Artificial sediment according to OECD 219
Composition (% w/w): Sphagnum peat (air dried, ground to ≤ 1mm): 4 %
Kaolin clay (content of Al2O3: 36.4 5):20 %
Sand (Sihelco 36): 76 %
Calcium carbonate (CaCO3): 0.4 %
Total organic carbon (TOC): 2.0 %
pH adjustment: Yes
pH of final sediment mixture: 7.3
Test organisms (species):
Chironomus riparius
Details on test organisms:
Species/strain: Chironomus riparius
Age: 2 – 3 days (first instar larvae)
Breeding method: Similar temperature and light conditions and in the same kind of water as used in the test
Kind of food: TetraMin Hauptfutter (TETRA-Werke, D 49304 Melle, Germany)
Amount of food: Day -1 – 5: 23 mg / vessel
Day 7 – 24: 47 mg/vessel
Feeding frequency: 3 times a week
Pretreatment: Finely ground and suspended in test water
Feeding of animals during test: Yes
Study type:
laboratory study
Test type:
static
Water media type:
freshwater
Type of sediment:
artificial sediment
Limit test:
no
Duration:
27 d
Exposure phase:
total exposure duration
Post exposure observation period:
None
Hardness:
Ca2+: approx. 2.0 mmol/L (as CaCO3)
Ca2+ and Mg2+: approx 2.5 mmol/L
(of dilution water)
Test temperature:
19.4 – 19.8 ºC
pH:
7.6 – 8.7
Dissolved oxygen:
≤ 69 %
Salinity:
Not applicable
Ammonia:
Not reported
Nominal and measured concentrations:
See table below:Nominal and measured concentrations
Details on test conditions:
Type of test: Chronic 27 days
Renewal of test solution: No
Volume of test vessels: 3 L
Amount/volume of sediment per vessel: 462 g (dry weight)
Volume of test medium per vessel: 1600 mL
Volume/animal: 80
Number of animals/vessel: 20
Number of vessels/ concentration: 4
Test performed in closed vessels due to significant volatility of TS: No, vessels covered with a watch-glass
Aeration of dilution water: Yes
Quality/Intensity of irradiation: 640 – 860 lux
Photoperiod: 16/8 hours light/dark with a 30 min transition period
Reference substance (positive control):
no
Key result
Duration:
27 d
Dose descriptor:
EC50
Effect conc.:
14.5 µg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
emergence rate
Remarks on result:
other: 11.8 – 17.8
Key result
Duration:
27 d
Dose descriptor:
NOEC
Effect conc.:
4 µg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
emergence rate
Remarks:
and development rate
Key result
Duration:
27 d
Dose descriptor:
LOEC
Effect conc.:
8 µg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
emergence rate
Remarks:
and development rate
Details on results:
The mean measured concentrations of the test item in the application solutions ranged from 92 – 95 % of the nominal concentrations.

One hour after application, the mean measured concentration of the test item in the water column corresponded to 72 and 76 % of the nominal concentrations of 8 and 32 µg/L.

Seven days after application, the mean measured concentration of the test item in the water column corresponded to 58 and 68 % of the nominal concentrations of 8 and 32 µg/L.

At the end of exposure, the mean measured concentration of the test item in the water column corresponded to 56 and 61 % of the nominal concentrations of 8 and 32 µg/L.

Test item concentrations in the pore water and sediment increased continuously throughout the exposure phase. In the 8 µg/L treatment group, measured concentrations reached a maximum of 3.5 µg/L in pore water and 1.13 µg/kg in sediment. In the 32 µg/L treatment group, measured concentrations reached a maximum of 17.1 µg/L in pore water and 5.7 µg/kg in sediment.

The correct preparation of the application solutions was confirmed. The low recoveries in the water samples 1 hour after application were presumably caused by transfer of the test item into the sediment and the pore water phase. The biological results are presented based on nominal concentrations.

Based on nominal concentrations, the 27 day EC10 for the arcsin-transformed emergence rate of pooled sexes was calculated by Probit analyses to be 4.6 µg/L (95% confidence limits 3.7 – 5.8 µg/L), the EC50 was calculated to be 14.5 µg/L (95 % confidence limits 11.8 – 17.8).
At nominal concentrations of 2, 4 and 8 µg/L there was no statistically significant difference in the development rate of male midges.
At nominal concentrations of 2, 4, 8 and 16 µg/L there was no statistically significant difference in the development rate of female midges.
At a nominal concentration of 32 µg/L no development rate could be calculated due to 0 % emergence.
The EC10 and EC50 for development rate could not be calculated due to the low inhibition rates.
The 27 day NOEC and the LOEC for development and emergence for Chironomus riparius were 4 and 8 µg/L, respectively.

See Tables 1 and 2.
Results with reference substance (positive control):
Not applicable
Reported statistics and error estimates:
For emergence rate and development rate the arithmetic mean values (mean), standard deviation (SD), minimum and maximum (min/max) were calculated from the four replicates per treatment. The values of the emergence rates and the development rates were normally distributed and were statistically evaluated on significant differences to the control by the multivariate Williams-test after a one-way analysis of variance (ANOVA). Statistical evaluations were done separately for emerged males and females (development rate) and with pooled sexes (emergence rate).

The 27-day EC10 and EC50 and the 95% confidence limits of the emergence rate (pooled sexes) were calculated by Probit analyses. The 27-day ECx values and the 95% confidence limits of the development rate of the midges could not be calculated due to the low inhibitory effect up to the highest test concentration that could be evaluated.

Nominal and measured concentrations:

Application solutions

Nominal concentration dinotefuran

[mg/L]

Measured concentration dinotefuran

[mg/L]

Measured concentration [%] of nominal

0.32

0.296

93

0.64

0.596

93

1.28

1.19

93

2.56

2.34

92

5.12

4.86

95

Water samples

Nominal concentration [µg/L]

Sampling day

[d]

measured concentration1[µg/L]

 

[% nominal]

0 (control)

0

n.d.

n.a.

27

n.d.

n.a.

8

0

5.73

72

7

4.66

58

27

4.50

56

32

0

24.3

76

7

21.7

68

27

19.4

61

Pore water samples

0 (control)

0

0.286*

n.a.

27

n.d.

n.a.

8

0

0.247

n.a.

7

2.53

n.a.

27

3.50

n.a.

32

0

1.35

n.a.

7

10.1

n.a.

27

17.1

n.a.

Sediment samples

0 (control)

0

n.d.

n.a.

27

n.d.

n.a.

8

0

0.275

n.a.

7

0.654

n.a.

27

1.13

n.a.

32

0

0.263

n.a.

7

2.64

n.a.

27

5.67

n.a.

1: corrected for recovery rate of spiked samples

*: excluded as outlier because of absence of test item in the corresponding water and sediment samples

n.d.: no test item detected

n.a.: not applicable

Table 1: Emergence rate of Chironomus riparius (males and females pooled) after 27 days of exposure

Nominal test item concentration [µg/L]

 

Control

2

4

8

16

32

sum inserted larvae / treatment

80

80

80

80

80

80

sum emerged midges / treatment

76

77

74

69

30

0

% emerged midges / treatment

95

96

93

86

38

0

emergence rate ERarc

1.4099

1.4016

1.2971

1.1920

0.6545

0

% of control

100

99.4

92.0

84.5

46.4

0

STAT

-

n.s.

n.s.

s

s

s

ERarc: arcsin-transformed emergence rate

STAT: results of a Williams t-test (α = 0.05, one-sided smaller)

n.s.:mean ERarcnot significantly lower than in the control

s:mean ERarcsignificantly lower than in the control

 

Table 2: Development rate for males and females

Females

Development rate / treatment

[day-1)

Nominal initial test item concentration [µg/L]

 

control

2

4

8

16

32

Mean

0.06465

0.06283

0.06377

0.06495

0.06325

n.a.

SD

0.00336

0.00189

0.00178

0.00060

0.00209

n.a.

min

0.06120

0.06070

0.06190

0.06440

0.06100

n.a.

max

0.06810

0.06470

0.06600

0.06580

0.06600

n.a.

n

4

4

4

4

4

4

% of control

100

97.2

98.6

100.5

97.8

n.a.

STAT

-

n.s.

n.s.

n.s.

n.s.

n.a.

STAT: results of a Williams t-test (α = 0.05, one-sided smaller)

n.s.mean ERarcnot significantly lower than in the control:

s:mean ERarcsignificantly lower than in the control

n.a.: not applicable (no midge emerged)

 

Males

Development rate / treatment

[day-1)

Nominal initial test item concentration [µg/L]

 

control

2

4

8

16

32

Mean

0.07412

0.07360

0.07295

0.07240

0.07085

n.a.

SD

0.00126

0.00226

0.00234

0.00062

0.00413

n.a.

min

0.07230

0.07080

0.07120

0.07150

0.06480

n.a.

max

0.07510

0.07580

0.07640

0.07290

0.07410

n.a.

n

4

4

4

4

4

4

% of control

100

99.3

98.4

97.7

95.6

n.a.

STAT

-

n.s.

n.s.

n.s.

s

n.a.

STAT: results of a Williams t-test (α = 0.05, one-sided smaller)

n.s.:mean ERarcnot significantly lower than in the control

s:mean ERarcsignificantly lower than in the control

n.a.: not applicable (no midge emerged)

 

Validity criteria fulfilled:
yes
Conclusions:
A clear dose response of the test item for development and emergence rate could be determined.
The 27 day NOEC and the LOEC for development and emergence for Chironomus riparius were 4 and 8 µg/L, respectively.
Based on nominal concentrations, the 27 day EC10 for the emergence rate was calculated to be 4.6 µg/L, the EC50 was calculated to be 14.5 µg/L .

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Key value for chemical safety assessment

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