N-[[3,5-dichloro-2-fluoro-4-(1,1,2,3,3,3-hexafluoropropoxy)phenyl]carbamoyl]-2,6-difluorobenzamide

Toxicity to soil macroorganisms except arthropods

Link to relevant study record(s)

Reference

Endpoint:

toxicity to soil macroorganisms except arthropods: short-term

Type of information:

experimental study

Adequacy of study:

key study

Study period:

16 May 2002 - 17 June 2002

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 207 (Earthworm, Acute Toxicity Tests)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: U.S. FDA 1987. Earthworm Subacute Toxicity. FDA Environmental Assessment Technical Guide No. 4.12.

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Details on preparation and application of test substrate:

- Method of mixing into soil: Appropriate amounts of test material were mixed into dry soil in each test vessel, then hydrated with deionised water and thoroughly mixed.
- Controls: Deionised water

Test organisms (species):

Eisenia fetida

Animal group:

annelids

Details on test organisms:

TEST ORGANISM
- Common name: Earthworm
- Source: Purchased from a commercial supplier
- Age at test initiation: The worms had well developed clitella
- Average weight of worms on day 0: 0.3680 g

ACCLIMATION
- Acclimation period: 17 days
- Acclimation conditions (same as test or not): Temperature during acclimation ranged from 18.6 to 21.9 °C. Worms were not fed during acclimation or testing.
- Health during acclimation (any mortality observed): During acclimation worms were not treated for disease and they were free of apparent disease, injuries, and abnormalities at the beginning of the test. No mortality was observed during the acclimation period.

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

yes

Total exposure duration:

14 d

Test temperature:

20 ± 2 °C

Moisture:

Deionised water was used to achieve a nominal moisture content of approximately 25 %.

Details on test conditions:

TEST SYSTEM
- Test container (material, size): Half gallon glass jars
- Amount of soil or substrate: 1 kg of hydrated artificial soil
- No. of organisms per container (treatment): 10
- No. of replicates per treatment group: 4
- No. of replicates per control: 4
- Pre-treatment of test organisms: Before the test, the worms were quickly and gently washed with deionised water, blotted on paper towels, and weighed.

PROPERTIES OF SOIL
- Composition (if artificial substrate): 70 % sand; 20 % kaolin clay; and 10 % finely ground sphagnum peat moss

EFFECT PARAMETERS MEASURED:
The number of surviving organisms and the occurrence of sub-lethal effects were determined visually and recorded initially and after 7 and 14 days. The time required to burrow was recorded after 0, 7, and 14 days, and the average wet weight of surviving worms was determined at the beginning of the test and after 14 days. Soil temperature was measured and recorded daily in each test vessel and the temperature in one control vessel was recorded continuously during the test.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: None; limit test
- Range finding study: Yes, 14 day study
- Test concentrations: 0, 1.1, 10, 100, 1000 and 10 000 mg/kg (dry weight)
- Results used to determine the conditions for the definitive study: Yes

Nominal and measured concentrations:

- Nominal concentration of 10 000 mg/kg

Reference substance (positive control):

yes

Remarks:

2-chloracetamide

Key result

Duration:

14 d

Dose descriptor:

LC50

Effect conc.:

> 10 000 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Key result

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

10 000 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: based on weight loss, survival, and sub-lethal effects other than weight loss.

Details on results:

There was 100 % survival in the control and 98 % survival at the single tested concentration. No sub-lethal effects were observed and all worms burrowed within 10 minutes.
Temperature during the test ranged from 19.6 to 22.0 °C. Survival and sub-lethal effect data generated by the toxicity test are presented in Table 1. One hundred percent survival occurred and no sub-lethal effects were observed in the control exposure. The average weight change of surviving worms is presented in Table 2; average weight loss of control worms was 9.0 %. All surviving worms exposed to the control and the single concentration of test material burrowed into the soil within 10 minutes on days 0, 7, and 14.

Results with reference substance (positive control):

The 14-day soil toxicity test conducted with the reference toxicant 2-chloracetamide resulted in an LC50 of 17 mg/kg, wet weight. This value was within the range normally obtained in the testing laboratory.

Reported statistics and error estimates:

The 7 and 14 day LC50 could not be calculated because survival at the single tested concentration exceeded 50 %. The NOEC was determined at 14 days using weight loss data. Because all worms exposed to the single concentration of test material burrowed within 10 minutes, the time to burrow data did not warrant statistical analysis. The survival and sub-lethal effect data did not require statistical analysis because 98 % survival occurred at the single tested concentration and no sub-lethal effects were observed. The weight loss data were demonstrated to be normally distributed with a Chi-square test and variances were demonstrated to be heterogeneous with a Bartlett’s test (α = 0.05). The weight loss data from the single treatment were compared to control data using a nonparametric “t” test.

Table 1: Survival and Sub-lethal Effects

Concentration (mg/kg)	Replicate	Number alive			Number Affected*
		Day 0	Day 7	Day 14	Day 0	Day 7	Day 14
0	1	10	10	10	0	0	0
	2	10	10	10	0	0	0
	3	10	10	10	0	0	0
	4	10	10	10	0	0	0
10 000	1	10	10	9	0	0	0
	2	10	10	10	0	0	0
	3	10	10	10	0	0	0
	4	10	10	10	0	0	0

* All surviving worms burrowed into the soil within 10 minutes on days 0, 7 and 14

 

Table 2: Average Weight of Worms

Concentration (mg/kg)	Replicate	No. Alive on Day 14	Average Weight (g)		% Change
			Day 0	Day 14
0	1	10	0.3920	0.3526	-10.1
	2	10	0.3640	0.3243	-10.9
	3	10	0.3724	0.3408	-8.5
	4	10	0.3296	0.3083	-6.5
10 000	1	9	0.3502	0.3212	-8.3
	2	10	0.3577	0.3436	-3.9
	3	10	0.3771	0.3625	-3.9
	4	10	0.4009	0.3811	-4.9

Validity criteria fulfilled:

yes

Conclusions:

The 14 day LC50 for worms exposed to the test material was greater than 10 000 mg/kg. The 14 day no-observed -effect-concentration (NOEC) was 10 000 mg/kg.

Executive summary:

The acute toxicity of the test material to Eisenia foetida was investigated in a limit test conducted in accordance with the standardised guidelines OECD 207 and U.S. FDA Earthworm Subacute Toxicity under GLP conditions.

Following a range-finding study, earthworms were exposed to the test material at nominal concentrations of 0 and 10 000 mg/kg in artificial soil for 14 days at a temperature of 20 ± 2 °C. The test media was artificial soil comprised of approximately 70 % sand, 20 % kaolin clay and 10 % finely ground sphagnum peat moss. The test material was added to dry artificial soil in each test vessel, deionised water was added, and the test vessels were thoroughly mixed. The moisture content was approximately 25 %. Additionally, a 14 day study was conducted with the positive control material 2-chloracetamide. The number of surviving organisms and the occurrence of sub-lethal effects were determined visually and recorded initially and after 7 and 14 days. The time required to burrow was recorded after 0, 7, and 14 days, and the average wet weight of surviving worms was determined at the beginning of the test and after 14 days.

There was 100 % survival in the control and 98 % survival at the single tested concentration. No sub-lethal effects were observed and all worms burrowed within 10 minutes. One hundred percent survival occurred and no sub-lethal effects were observed in the control exposure. The average weight loss of control worms was 9.0 %. All surviving worms exposed to the control and the single concentration of test material burrowed into the soil within 10 minutes on days 0, 7, and 14.

The test conducted with the reference toxicant 2-chloracetamide resulted in an LC50 of 17 mg/kg, wet weight. This value was within the range normally obtained in the testing laboratory.

The 14 day LC50 for worms exposed to the test material was greater than 10 000 mg/kg. The single tested concentration (10 000 mg/kg) allowed 98 % survival. The 14 day no-observed -effect-concentration (NOEC) was 10 000 mg/kg based on weight loss, survival, and sub-lethal effects other than weight loss.

Description of key information

The 14 day LC50 for worms exposed to the test material was greater than 10 000 mg/kg. The 14 day NOEC was 10 000 mg/kg.

Key value for chemical safety assessment

Short-term EC50 or LC50 for soil macroorganisms:

10 000 mg/kg soil dw

Additional information

The acute toxicity of the test material to Eisenia foetida was investigated in a limit test conducted in accordance with the standardised guidelines OECD 207 and U.S. FDA Earthworm Subacute Toxicity under GLP conditions. The study was awarded a reliability score of 1 in accordance with the criteria set forth by Klimisch et al. (1997).

Following a range-finding study, earthworms were exposed to the test material at nominal concentrations of 0 and 10 000 mg/kg in artificial soil for 14 days at a temperature of 20 ± 2 °C. The test media was artificial soil comprised of approximately 70 % sand, 20 % kaolin clay and 10 % finely ground sphagnum peat moss. The test material was added to dry artificial soil in each test vessel, deionized water was added, and the test vessels were thoroughly mixed. The moisture content was approximately 25 %. Additionally, a 14 day study was conducted with the positive control material 2-chloracetamide. The number of surviving organisms and the occurrence of sub-lethal effects were determined visually and recorded initially and after 7 and 14 days. The time required to burrow was recorded after 0, 7, and 14 days, and the average wet weight of surviving worms was determined at the beginning of the test and after 14 days.

There was 100 % survival in the control and 98 % survival at the single tested concentration. No sub-lethal effects were observed and all worms burrowed within 10 minutes. One hundred percent survival occurred and no sub-lethal effects were observed in the control exposure. The average weight loss of control worms was 9.0 %. All surviving worms exposed to the control and the single concentration of test material burrowed into the soil within 10 minutes on days 0, 7, and 14.

The test conducted with the reference toxicant 2-chloracetamide resulted in an LC50 of 17 mg/kg, wet weight. This value was within the range normally obtained in the testing laboratory.

The 14 day LC50 for worms exposed to the test material was greater than 10 000 mg/kg. The single tested concentration (10 000 mg/kg) allowed 98 % survival. The 14 day no-observed -effect-concentration (NOEC) was 10 000 mg/kg based on weight loss, survival, and sub-lethal effects other than weight loss.