Propanoic acid, 2-(4-chloro-2-methylphenoxy)-, 2-ethylhexyl ester, (2R)-

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:

from 1999-11-18 to 2000-07-31

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 207 (Earthworm, Acute Toxicity Tests)

Deviations:

no

GLP compliance:

not specified

Remarks:

the study was run under quality assurance inspection

Specific details on test material used for the study:

Batch: N3447
Purity: 92.6 %

Analytical monitoring:

no

Vehicle:

yes

Remarks:

acetone

Details on preparation and application of test substrate:

Acetone was used in the preparation of the test soils, therefore, a solvent control was included in the test.
The test item was dissolved in acetone (5 mL in range finding test and 15 mL in main test).

Test organisms (species):

Eisenia fetida

Animal group:

annelids

Details on test organisms:

TEST ORGANISM
- Common name: Earthworm
- Source: Blades Biological, Kent
- Age at test initiation: at least 2 months (with clitellum)
- Weight at test initiation: between 300 and 600 mg

ACCLIMATION
- Acclimation period: at least 7 days prior to commencement of the study
- Acclimation conditions: to laboratory conditions - 20 - 21 °C under constant illumination, in an artificial soil of the same composition as that used for testing. They were fed with horse manure ad libitum during the acclimatisation period.
- Health during acclimation: good health

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

yes

Total exposure duration:

14 d

Test temperature:

20 - 21 °C

pH:

6.12 - 6.43

Moisture:

30 - 33 %

Details on test conditions:

Limit test with four test vessels at a nominal concentration of 1000 mg MCPP-P 2-EHE/kg soil, four control vessels and four solvent control vessels (acetone). Forthy earthworms were exposed to the test concentration and forthy were placed in both the control and solvent control. The worms were examined for mortality after 7 and 14 days exposure. At days 0 and 14 the live weights of the worms were measured and the effect of exposure on body weight was assessed. Earthworms were not fed throughout the test.

TEST SYSTEM
- Test container: Glass beakers of ca. 1 litre capacity covered with perforated plastic film to retard evaporation
- Amount of soil or substrate: ca. 750 g (wet weight) soil
- No. of organisms per container (treatment): 10
- No. of replicates per treatment group: 4
- No. of replicates per control: 4
- No. of replicates per vehicle control: 4

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
Artificial soil was used. It was prepared according to the OECD 207 guideline.
- % industrial sand: 70 (w/w)
- % Sphagnum moss peat: 10 (w/w)
- % kaolinite clay: 20 (w/w)
- pH adjusted with 0.5 % CaCO3 of the total dry weight
- Moisture content: ca. 35%

OTHER TEST CONDITIONS
- Photoperiod: continuous illumination
- Light intensity: ca. 850 lux

VEHICLE CONTROL PERFORMED: yes

TEST CONCENTRATIONS
- Range finding study: yes
- Test concentrations: 0, 1, 10, 100 and 1000 mg test item/kg dry weight soil
- Spacing factor for test concentrations: 10

Nominal and measured concentrations:

1000 mg product/kg dry weight soil

Reference substance (positive control):

no

Key result

Duration:

14 d

Dose descriptor:

LC50

Effect conc.:

> 1 000 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.:

1 000 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Limit Test:

No dead worms were recorded during the test. There was no mortality in the control vessels at the end of the test. The test is therefore considered to be valid.

Earthworms were observed for any behavioural or pathological signs throughout the test period. All worms burrowed into the soil within a few minutes of addition to the vessels and no worms were observed on the soil surface of any vessel throughout the duration of the study. No unusual behaviour or pathological signs were noted in both test and control vessels.

As there were no dead worms in the treated vessels, it is concluded that the LC₅₀of MCPP-P 2-EHE to earthworms is greater than 1000 mg/kg under the conditions of the test. The no observed effect concentration (NOEC) for earthworm survival is 1000 mg/kg under test conditions.

The individual weights of worms in test and control vessels were recorded at the start and at the termination of the limit test. The mean weight per treatment group was calculated and the average percentage weight change per worm, over the 14 day test period determined. After 14 days, the mean changes in weight for the treated, solvent control and control worms were 0.064 g, 0.024 g and 0.045 g, respectively. This gave percentage weight changes of -16 %, -6 % and -11 %, respectively. Statistical analysis indicated a significant difference between all three treatment groups (p < 0.001). Although this may indicate that MCPP-P 2-EHE has an effect on earthworm weight at 1000 mg/kg, the apparent change may reflect biological variation rather than a direct relationship to test material, as there was a similar effect noted between the two controls. This differential weight loss was not evident in the range finding test where a similar weight change was seen in both control and treated earthworms at the end of the exposure period. Further, the weight loss of the controls in the range finding test was similar to that seen for the test vessels in the limit study.

Table 1: Cumulative Mortality Recorded During the Limit Test

Test vessel No.	Nominal concentration (mg/kg)	Time (days)
		7	14
1 2 3 4	1000	0 0 0 0	0 0 0 0
5 6 7 8	0 + solvent	0 0 0 0	0 0 0 0
9 10 11 12	0	0 0 0 0	0 0 0 0

 

Table 2: Mean Body Weight per Earthworm in the Treatment and Control Groups at the Start and End of the Limit Test and Percentage Weight Change

Observations	Concentration (mg/kg)
	1000	0 + Solvent	0
Mean weight at Day 0	0.407	0.402	0.409
Mean weight at Day 14	0.343	0.378	0.364
Weight change over 14 days	-0.064	-0.024	-0.045
% of original weight at Day 14	84	94	89
% weight change	-16 %	-6 %	-11 %

 

Validity criteria fulfilled:

yes

Conclusions:

It was concluded that the LC50 of MCPP-P 2-EHE to earthworms is greater than 1000 mg/kg and the No Observed Effect Concentration (NOEC) for survival is determined to be 1000 mg/kg under the conditions of the test.

Executive summary:

The toxicity of MCPP-P 2-EHE to earthworms (Eisenia fetida andrei) was assessed by conducting a limit test at 1000 mg product per kg dry weight of soil over a 14 day period. The test was conducted in accordance with OECD (1984) Guideline 207 under quality assurance inspection. Following the results of a range finding test which indicated no effect at 1000 mg/kg soil, the limit test was conducted with four test vessels at a nominal concentration of 1000 mg/kg soil, four control vessels and four solvent control vessels (acetone). Forty earthworms were exposed to the test concentration and forty were placed in both the solvent and non-solvent controls. The worms were examined for mortality after 7 and 14 days exposure. At days 0 and 14 the live weights of the worms were measured and the effect of exposure on body weight was assessed. There were no deaths at 1000 mg/kg. It is concluded that the LC50 of MCPP-P 2-EHE to earthworms is greater than 1000 mg/kg and the No Observed Effect Concentration (NOEC) for survival is determined to be 1000 mg/kg under the conditions of the test. The weight loss of earthworms in the treated vessels (-16 %) was found to be significantly different from the weight change in both the solvent (-6 %) and non-solvent (-11 %) control vessels. Although this indicates that MCPP-P 2-EHE may have an effect on earthworm weight loss at the limit concentration, this change may reflect biological variation rather than be directly related to test material. This is evidenced by the difference between the two control vessels. The weight loss was not evident in the range finding test where no difference was observed in weight change between control and treated earthworms at the end of the exposure period.

Description of key information

The LC50 for MCPP-P 2-EHE towards earthworms was determined to be > 1000 mg test item/kg soil and the NOEC to be 1000 mg test item/kg soil under the test conditions.

Key value for chemical safety assessment

Long-term EC10, LC10 or NOEC for soil macroorganisms:

1 000 mg/kg soil dw

Additional information

The toxicity of MCPP-P 2-EHE to earthworms (Eisenia fetida andrei) was assessed by conducting a limit test at 1000 mg product per kg dry weight of soil over a 14 day period [MCPP Task Force, 2000]. The test was conducted in accordance with OECD (1984) Guideline 207 under quality assurance inspection. Following the results of a range finding test which indicated no effect at 1000 mg/kg soil, the limit test was conducted with four test vessels at a nominal concentration of 1000 mg/kg soil, four control vessels and four solvent control vessels (acetone). Forty earthworms were exposed to the test concentration and forty were placed in both the solvent and non-solvent controls. The worms were examined for mortality after 7 and 14 days exposure. At days 0 and 14 the live weights of the worms were measured and the effect of exposure on body weight was assessed. There were no deaths at 1000 mg/kg. It is concluded that the LC50 of MCPP-P 2-EHE to earthworms is greater than 1000 mg/kg and the No Observed Effect Concentration (NOEC) for survival is determined to be 1000 mg/kg under the conditions of the test. The weight loss of earthworms in the treated vessels (-16 %) was found to be significantly different from the weight change in both the solvent (-6 %) and non-solvent (-11 %) control vessels. Although this indicates that MCPP-P 2-EHE may have an effect on earthworm weight loss at the limit concentration, this change may reflect biological variation rather than be directly related to test material. This is evidenced by the difference between the two control vessels. The weight loss was not evident in the range finding test where no difference was observed in weight change between control and treated earthworms at the end of the exposure period.