Ethyl [2-(4-phenoxyphenoxy)ethyl]carbamate

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:

15 May 1990 to 29 May 1990

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 207 (Earthworm, Acute Toxicity Tests)

Version / remarks:

1984

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Immediately after preparation of treated moistened soil on Day 0, samples were taken from each group and stored at -20°C. On Day 14 of the study, further samples were taken from each group and stored at -20°C. Samples were then packed in dry ice and sent to the Sponsor.

Vehicle:

yes

Remarks:

Acetone

Details on preparation and application of test substrate:

The test compound was applied as solutions in acetone. The dose concentrations were calculated to give the same volume at all dose levels. Negative control soil was treated with acetone only. For each group the dose was thoroughly mixed with a small pre-mix of weighed soil and the vehicle was allowed to evaporate off to incorporation with the main soil bulk. Water was gradually mixed with the treated soil to give a moisture content equivalent to of the dry weight.

Test organisms (species):

Eisenia fetida

Animal group:

annelids

Details on test organisms:

TEST ORGANISM
- Common name: Earthworm
- Weight at test initiation: 330 - 377 mg

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

no

Total exposure duration:

14 d

Test temperature:

23 - 24 °C

pH:

5.9 at the beginning of the study

Moisture:

At the initiation of the study: 35 %
At termination of the study: 23 - 24 %

Details on test conditions:

TEST SYSTEM
- Test container: 1-L polythene containers each lined with a polythene bag. The prepared medium for each group was divided equally between four containers and ten worms were randomly allocated to
each and placed on the soil surface. Each bag was sealed with an elastic band and perforated above soil level to retain moisture whilst providing a degree of ventilation.
- No. of organisms per container (treatment): 10
- No. of replicates per treatment group: 4
- No. of replicates per control: 4

SOURCE AND PROPERTIES OF SUBSTRATE:
- % sand (w/w): 69.7
- % sphagnum peat (w/w): 10
- % clay (w/w): 20
- % calcium carbonate (w/w): 0.3

OTHER TEST CONDITIONS
- Photoperiod: continuous

EFFECT PARAMETERS MEASURED:
- Counts of worms: On Days 7 and 14 the medium was emptied from the test containers and the worms removed for counting. Mortality was assessed by testing the reaction of each worm to a mechanical stimulus at either end. On Day 7 the medium was returned to the containers and surviving worms replaced on the surface
- Health and mortalities: Any worms visible on the soil surface were observed daily for behavioural or pathological signs and mortalities were recorded.
- Weights: Weights of worms were recorded in treatment replicates on Days 0 and 14 (Time ‘0' is that time point when the worms were allocated to treatment, indicating the start of Day 1, the first 24 hours period of the test).

VEHICLE CONTROL PERFORMED: no

Nominal and measured concentrations:

Nominal concentrations: 62.5, 125, 250, 500 and 1000 ppm (mg/kg dry soil)

Reference substance (positive control):

yes

Remarks:

Chloroacetamide; only data are included for comparative purposes, study was carried out seperately under similar experimental conditions

Key result

Duration:

14 d

Dose descriptor:

LC50

Effect conc.:

850 other: ppm

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: corresponding to 850 mg/kg dry soil

Details on results:

An overview of the results is provided in Table 1 - Table 2 in 'Any other information on results incl. tables'.
- Mortality at end of exposure period: Six dead worms were observed on the surface of the soil in Group 6 (1000 ppm) between Day 7 and Day 14 counts. These worms were recorded and discarded. No further worms were observed on the soil surface and all surviving worms observed at Days 7 and 14 appeared normal
- Body weights: Treatment-related body weight increases were noted for all treatment groups:
- negative control: 7.4 %
- 62.5 ppm: 9.6 %
- 125 ppm: 18.1 %
- 250 ppm: 18.1 %
- 500 ppm: 21.5 %
- 1000 ppm: 34.8 %

Results with reference substance (positive control):

An overview of the results is provided in Table 3 - Table 4 in 'Any other information on results incl. tables'.
LC50 values for the positive control were found to be as follows:
Day 7 LC50 43.1 ppm (95 % confidence limits 34 - 57.6 ppm)
Day 14 LC50 24.6 ppm (95 % confidence limits 20.2 - 30.5 ppm)

Reported statistics and error estimates:

Because of the limited number of mortalities, it was not possible to determine the LC50 value at Day 7 in this study. This value must lie in excess of the maximum treatment level of 1000 ppm. The Day 14 LC50 value was calculated by a method of probit analysis.

Table 1. Cumulative mortalities - Test substance

Group	Treatment (ppm)	No. of worms	Day of study		Total as %
			7	14
1	0 (Negative control)	40	0	0	0
2	62.5	40	0	0	0
3	125	40	0	0	0
4	250	40	0	0	0
5	500	40	0	1	2.5
6	1000	40	2	29	72.5

Table 2 Group mean weight of worms (mg) - Test substance

Group	Treatment (ppm)	No. of worms	Day of study		Percentage increasse
			7	14
1	0 (Negative control)	40	353	379	7.4
2	62.5	40	353	387	9.6
3	125	40	354	418	18.1
4	250	40	353	417	18.1
5	500	40	353	429	21.5
6	1000	40	353	476	34.8

Table 3. Cumulative mortalities following treatment - Positive control data

Group	Treatment rate (ppm)	No. of worms	Day of study	Day of study	Total as %
			7	14
1	Negative Control 0	40	0	1	2.5
2	Chloroacetamide 5	40	2	2	5.0
3	Chloroacetamide 10	40	0	2	5.0
4	Chloroacetamide 20	40	3	8	20.0
5	Chloroacetamide 40	40	18	34	85.0
6	Chloroacetamide 80	40	34	40	100

Table 4. Group mean weights of worms (mg) - Positive control data

Group	Treatment rate (ppm)	Day of study	Day of study	Percentage Increase
		0	14
1	Negative Control 0	200	232	16.0
2	Chloroacetamide 5	200	231	15.5
3	Chloroacetamide 10	211	222	5.2
4	Chloroacetamide 20	202	221	9.4
5	Chloroacetamide 40	206	312	51.5
6	Chloroacetamide 80	198	-	-

Validity criteria fulfilled:

yes

Conclusions:

In an acute toxicity test with earthworms, performed in accordance with OECD TG 207, based on nominal concentration, the 14-day LC50 for the test substance to earthworms (Eisenia fetida) was 850 ppm (mg/kg dry soil) with 95% confidence limits of 761 - 944 ppm.

Executive summary:

In an acute toxicity study, earthworms (Eisenia fetida) were exposed to the test substance for 14 days in artificial soil. The study was performed following OECD TG 207 and in compliance with GLP. The test was conducted in 1 L polyethylene containers with polythene bags, containing artificial moist soil. Nominal soil concentrations of 0 (negative control), 62.5, 125, 250, 500 and 1000 ppm (mg/kg dry soil) were tested in 4 replicates of 10 worms each. Jars were maintained at 23 - 24°C under continuous light. Soil moisture was 35% and 23 - 24% of the dry weight at the start and the end of the test, respectively. A reference product was tested in a separate test and gave an acceptable result. Six dead worms were on the surface of the soil in Group 6 (1000 ppm) between Day 7 and Day These worms were recorded and discarded. No further were observed on the soil surface and all surviving worms observed at Days 7 and 14 appeared normal.

Because of the limited number of mortalities at Day 7, it was not possible to determine the Day 7 LC50 value. This value must lie in excess of the maximum treatment level of 1000 ppm. The Day 14 LC50 value was found to be 850 ppm (mg/kg dry soil) with 95% confidence limits of 761 - 944 ppm (mg/kg dry soil).

Description of key information

All available data was assessed and the study representing the worst-case effect is included here as key. The result can be considered worst-case and is selected for the CSA.

14-d LC50 = 850 mg/kg soil dw, Eisenia fetida, mortality, OECD TG 207, Hakin 1990

Key value for chemical safety assessment

Short-term EC50 or LC50 for soil macroorganisms:

850 mg/kg soil dw

Additional information

OECD TG 207, Hakin 1990

In an acute toxicity study, earthworms (Eisenia fetida) were exposed to the test substance for 14 days in artificial soil. The study was performed following OECD TG 207 and in compliance with GLP. The test was conducted in 1 L polyethylene containers lined with polythene bags, containing artificial moist soil. Nominal soil concentrations of 0 (negative control), 62.5, 125, 250, 500 and 1000 ppm (mg/kg dry soil) were tested in 4 replicates of 10 worms each. Jars were maintained at 23 - 24°C under continuous light. Soil moisture was 35% and 23 - 24% of the dry weight at the start and the end of the test, respectively. A reference product was tested in a separate test and gave an acceptable result. Six dead worms were on the surface of the soil in the 1000 ppm treatment between Day 7 and Day 14 counts. These worms were recorded and discarded. No further were observed on the soil surface and all surviving worms observed at Days 7 and 14 appeared normal.

Because of the limited number of mortalities at Day 7 (2 un the 1000 ppm treatment), it was not possible to determine the Day 7 LC50 value. This value must lie in excess of the maximum treatment level of 1000 ppm. The Day 14 LC50 value was found to be 850 ppm (mg/kg dry soil) with 95% confidence limits of 761 - 944 ppm (mg/kg dry soil).