dinotefuran (ISO); 1-methyl-2-nitro-3-(tetrahydro-3-furylmethyl)guanidine

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

28/02/2000 - 31/08/2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP, Guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1300 (Daphnid Chronic Toxicity Test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Duplicate samples were taken from the freshly prepared test media of all concentrations and the control at days 0, 12 and 16. Additional samples from the old test solution were taken on days 14 and 19. All samples were stored frozen at approximately -20°C until analysis.

Vehicle:

no

Test organisms (species):

Daphnia magna

Details on test organisms:

Strain / Clone: Daphnia magna Straus, Clone 5
Source: University of Sheffield, UK
Age: < 24 hours
Breeding method: The daphnia were cultured und the same environmental conditions as used in the test
Kind of food: 1:1mixture of green algae (Scenedesmus subspicatus) and fish food suspension (Tetra Min Hauptfutter)
Amount of food: 0.10 – 0.25 mg TOC/daphnia/day
Feeding frequency: each working day
Pretreatment: not reported.
Feeding of animals during test: Yes

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

21 d

Post exposure observation period:

none

Hardness:

250 mg/L (as CaCO3)

Test temperature:

20°C

pH:

7.9 - 8.6

Dissolved oxygen:

7.6 - 8.0 mg/L

Salinity:

not applicable

Nominal and measured concentrations:

See table below

Reference substance (positive control):

no

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks:

mortality and growth

Details on results:

The effect of MTI-446 on the survival, reproduction and growth was determined in a 21 day semistatic dose response test. The nominal test concentrations were 6.25, 12.5, 25, 50 and 100 mg/L (See Table :Concentration" below). The measured concentration in the 100 mg/L treatment group ranged from 94 – 96% of nominal. Therefore, all biological results are reported based on nominal concentrations.

The NOEC for survival, reproduction and growth was 100 mg/L, see "effect data" table below.

The body length of each surviving adult at the end of exposure was determined by the use of a binocular. The mean body length of the daphnids in the control was 3.77 ± 0.08 mm. The mean body length in the 6.25, 12.5, 25, 50 and 100 mg/L test item groups were 3.77 ± 0.04, 3.75 ± 0.08, 3.77 ± 0.07, 3.75 ± 0.08 and 3.78 ± 0.05 mm , respectively.

There was not statistically significant effect on the mean body weight length of adult daphnia using a Williams-test (one-sided smaller, α = 0.05)

Results with reference substance (positive control):

Not applicable

Reported statistics and error estimates:

Significant differences in the reproduction rate and the body length of the adult daphnids were evaluated by testing the mean reproduction rate and the mean body length for statistically significant differences to the corresponding control values by the multiple Williams-test after a one-way analysis of variance (ANOVA).

Concentration:

Conc 1	Conc 2	Conc 3	Conc 4	Conc 5	Conc 6
Control	6.25 mg/L	12.5 mg/L	25 mg/L	50 mg/L	100 mg/L

Effect data:

Total number of alive, young daphnids per test concentration (cumulative numbers)

Exposure day	Nominal concentration [mg/L]
	Control	6.25	12.5	25	50	100
0	0	0	0	0	0	0
1	0	0	0	0	0	0
2	0	0	0	0	0	0
5	0	0	0	0	0	0
7	0	0	0	0	0	0
9	87	92	85	83	84	66
12	306	252	290	264	265	239
14	335	252	314	264	265	244
16	583	467	526	477	516	473
19	722	598	679	602	600	634
21	722	598	679	602	621	653
% of control*	100	82.8	94.0	83.4	86.0	90.4

* based on results of d 21

Number of alive offspring reproduced per surviving adult within 21 days of exposure

Replicate number	Nominal concentration [mg/L]
	Control	6.25	12.5	25	50	100
1	80	85	74	81	54	73
2	58	68	59	77	59	74
3	76	66	71	30	64	63
4	80	59	71	71	62	60
5	85	66	67	35	75	59
6	63	72	79	71	66	75
7	81	*	69	73	73	79
8	63	77	69	79	56	72
9	74	45	51	55	44	55
10	62	58	69	30	68	43
mean	72.2	66.2	67.9	60.2	62.1	65.3
±SD	9.8	11.6	7.8	21.0	9.3	11.2
n	10	9	10	10	10	10
CV %	13.5	17.5	11.5	34.8	15.0	17.2
Mean in %	100	91.7	94.0	83.4	86.0	90.4
STAT	-	n.s.	n.s.	n.s.	n.s.	n.s.

CV %: coefficient of variation in %: (SD_x/mean_x) x 100%

STAT: result of a Williams-test with the mean values of alive offspring (one-sided smaller, α = 0.05)

n.s.:mean value not significantly lower than in the control

*: test animal died throughout the exposure phase

NOEC_{survival, reproduction}: 100 mg/L

LOEC_{survival, reproduction}: ≥ 100 mg/L

Validity criteria fulfilled:

yes

Conclusions:

MTI-446 had no toxic effects on survival, reproduction and growth of adult Daphnia magna in a 21 day test.

Reference 2

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

22 October 2002 - 10 December 2003

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

The aquatic species shown to be most sensitive to dinotefuran was the chironomid
(Chironomus riparius) following both acute and chronic exposure. The acute 48 h LC50 was
72.1 μg/l and the 27 d NOEC was 2.54 μg/l. These results are consistent with the opinion
that daphnids (the most usual aquatic invertebrate tested) are not as susceptible to
neonicotinoid insecticides as other invertebrates. Information on endpoints for other
neonicotinoids (e.g. imidacloprid, clothianidin) is available in the EFSA conclusions/Review

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

other: OECD 219 (draft)

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

Test organisms (species):

other aquatic arthropod: 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

Test type:

static

Water media type:

other: reconstituted water (M7-medium)

Limit test:

no

Total exposure duration:

27 d

Test temperature:

19.4 - 19.8

pH:

7.6 - 8.7

Dissolved oxygen:

at least 6.2 mg/L

Key result

Duration:

27 d

Dose descriptor:

NOEC

Effect conc.:

2.88 µg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

other: emergence ratio, development

Remarks on result:

other: Based on lowest initial measured conc. in water samples (72%) at lowest conc. measured (8 µg/l). Consequently NOEC is 0.72 x 4 µg/l = 2.88 µg/L

Details on results:

Toxic effects of the test item MTI-446 on the development of sediment-dwelling larvae of the midge Chironomus riparius in water-sediment systems were investigated following the Proposal for a BBA-Guideline: "Effects of plant protection products on the development of sediment-dwelling larvae of Chironomus riparius in a water-sediment system" (1995), and the OECD Guidelines for Testing of Chemicals, Proposal for a new Guideline 219, Draft Document: "Chironomid Toxicity Test Using Spiked Water" (2001).
First-instar larvae of Chironomus riparius were exposed for a period of 27 days until full maturation of the larvae to adult midges. The test parameters of the study were the development time/rate of the midges and the emergence ratio as the number of fully emerged male and female midges.
The test item was applied to the water column in static water-sediment systems. The nominal initial test item concentrations in the overlaying water columns were 2, 4, 8, 16 and 32 µg/L MTI-446. A control (water-sediment systems without test item application) was tested in parallel.
The mean analytically measured concentrations of MTI-446 in the water columns one hour after the test item application corresponded to 72 and 76% of the nominal concentrations in the analysed test concentrations of 8 and 32 µg/L. Seven days later the concentrations in the water columns had fallen to 58 and 68%, after 27 days to 56 - 61% of the nominal initial concentrations. In the pore water and sediment, the concentrations of MTI-446 continuously increased during the study period. At the test concentration of nominal 8 µg/L, the concentration in pore water was in maximum 3.5 µg/L, and in the sediment 1.13 µg/kg at study termination on Day 27. At nominal 32 µg/L, maximum 17.1 µg/L were found in the pore water and 5.7 µg/kg in the sediment.
The correct preparation of the application solutions was analytically confirmed. The lower measured values in the water samples one hour after application (72 and 76% of the nominal initial values, i.e. average 74% of nominal) were presumably caused by diffusion and adsorption of MTI-446 into the pore water and sediment. All biological results are therefore reported in terms of the nominal initial concentrations of the test item as well as in terms of the analytically measured concentrations one hour after test item application.
First at the test concentrations of nominal initial 8 and 16 µg/L the mean emergence ratios of the midges (pooled sexes) were statistically significantly reduced compared to the control. At the highest test concentration of nominal initial 32 µg/L no midges emerged.
At the test concentration of nominal initial 16 µg/L the males developed slightly, but statistically significantly, more slowly than in the control. The mean development rate of the females was not statistically significantly reduced at this test concentration. At the highest test concentration of nominal initial 32 µg/I the development rates could not be calculated because no midges emerged.
Thus, the 27-day NOEC of MTI-446 (highest tested concentration without toxic effects) for Chironomus riparius in this water-sediment study was 4 µg/L. Based on the analytically measured initial concentrations in the water columns one hour after application the NOEC corresponds to 3 µg/L. The 27-day LOEC (lowest concentration tested with toxic effects) was 8 µg/L due to the reduced emergence ratio of the larvae. Based on the analytically measured initial concentrations in the water columns the LOEC corresponds to 5.9 pa /L.
Based on nominal concentrations, the 27-day EC10 for the emergence ratio of pooled sexes was calculated to be 4.6 µg/L (95% confidence limits 3.7 — 5.8 µg/L), the calculated 27-day EC50 was 14.5 µg/L (95% confidence limits 11.8 — 17.8 µg/L). The 27-day EC10 or EC50 for the development rate could not be calculated due to low inhibition rates

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 concentration^1[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 ofChironomus 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

Executive summary:

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 .

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

2.88 µg/L