N-methyl-N-[C18-(unsaturated)alkanoyl]glycine

Toxicity to soil macroorganisms except arthropods

Link to relevant study record(s)

Reference

Endpoint:

toxicity to soil macroorganisms except arthropods: long-term

Type of information:

experimental study

Adequacy of study:

key study

Study period:

24 Aug - 23 Oct 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 222 (Earthworm Reproduction Test (Eisenia fetida/Eisenia andrei))

Version / remarks:

29 Jul 2016

Deviations:

yes

Remarks:

Minor deviations in water content and temperature. No effect on study outcome expected.

GLP compliance:

yes (incl. QA statement)

Remarks:

Landesamt für Umwelt, Wasserwirtschaft und Gewerbeaufsicht, Mainz, Germany (8 Apr 2015)

Analytical monitoring:

no

Vehicle:

no

Details on preparation and application of test substrate:

- Method of mixing into soil: The appropriate amounts of test item were weighed into a glass vessel, then mixed and flushed with appropriate amounts of demineralised water for adjustment of water content of the artificial soil onto the necessary amount of artifical soil and then mixed into the test medium for the test.
- Controls: Benomyl (CAS No. 17804-35-2) was used as positive control.

Test organisms (species):

Eisenia andrei

Animal group:

annelids

Details on test organisms:

TEST ORGANISM
- Common name: Earthworms
- Source: In-house breeds of testing facility.
- Age at test initiation: At least 2 months, with a clitellum
- Weight at test initiation: 294 - 598 mg

ACCLIMATION
- Acclimation period: 40 h
- Acclimation conditions: Same as test. The worms were adapted to an aliquot of the same batch of artificial soil used during the test. The acclimatisation was performed using 500 g of the artificial soil mixed with 0.5 g horse manure per worm and demineralised water in 10 L stainless steel buckets.

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

no

Total exposure duration:

56 d

Remarks:

Observation times 28 d (mortality) and 56 d (reproduction).

Test temperature:

19.4 - 23.4 °C

pH:

6.3 - 7.0 (Day 0)
6.4 - 6.5 (Day 56)

Moisture:

47.85 - 56.16% of water holding capacity (Day 0)
61.46 - 73.04% of water holding capacity (Day 56)

Details on test conditions:

TEST SYSTEM
- Test container: 1 L glass preserving jars closed with glass lids.
- Amount of soil or substrate: 500 g artificial soil (dry weight)
- No. of organisms per container: 10
- No. of replicates per treatment group: 4
- No. of replicates per control: 8

OTHER TEST CONDITIONS
- Photoperiod: 16 h
- Light intensity: 500 lux (Osram L 18/840 tubes, cool white spectrum)
- Feeding: One day after the start of the test and then every week, each test vessel was fed with 5 g air-dried finely ground horse manure (horses were not treated with pharmaceuticals) and 6 mL of deionised water.

EFFECT PARAMETERS MEASURED:
- Mortality: after 28 d
- Reproduction (juvenile production: offspring number): after 56 d
- Weight change adult worms: after 28 d

TEST CONCENTRATIONS
- Spacing factor for test concentrations: Approximately 1.8

Nominal and measured concentrations:

95, 171, 309, 555, and 1000 mg/kg dry soil (nominal targeted)
97.2, 174.8, 315.9, 566.7, and 1020.5 mg/kg dry soil (actually weighed in)

Reference substance (positive control):

yes

Remarks:

Benomyl (CAS No. 17804-35-2)

Duration:

56 d

Dose descriptor:

NOEC

Effect conc.:

171 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks:

Offspring number

Duration:

56 d

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks:

Offspring number

Details on results:

- Mortality at end of exposure period: No mortality of adult animals after 28 d occurred in any replicate of the control and the treatment levels of 95, 171 and 555 mg/kg. At the treatment levels of 309 and 1000 mg/kg only one adult worm died.
- Changes in body weight of live adults (% of initial weight) at end of exposure period: Mean weight change of worms after 28 d was - 8% (control) and -3 to -9% (treatments).
- No. of offspring produced: The mean number of juvenile worms after 56 d was 97 (control) and 74 to 100 (treatments).

Results with reference substance (positive control):

- Results with reference substance valid? Yes, the result was within the range of 0.8 - 5 mg/kg required by OECD guideline 222.
- Relevant effect levels: EC50 (56 d) = 1.4 mg/kg dry soil

Reported statistics and error estimates:

Biological data was analysed with ToxRat Professional.
The following statistical test were conducted: Shapiro-Wilk's Test on Normal Distribution, Levene's Test on Variance Homogeneity (with residuals), Trend analysis by Contrasts (monotonicity of concentration/response), Williams Multiple Sequential t-test Procedure, Qualitative Trend Analysis by Contrasts (monotonicity of concentration/response), ChiSquare Table Test with Bonferroni Correction

VALIDITY

All validity criteria were met (Table 1) and the results of the test are therefore valid.

Table 1. Validity data

Parameter	Demand	Found	Assessment
Offspring in each control replicate	≥ 30 juveniles	at least 69	Valid
Coefficient of variation of reproduction in the controls	≤ 30 %	20.5 %	Valid
Adult mortality in the controls over the initi-al 28 days	≤ 10 %	0.0 %	Valid

 

MORTALITY

No mortality of adult animals occurred after 28 d in any replicate of the control and the treatment levels of 95, 171, and 555 mg/kg. At the treatment levels of 309 and 1000 mg/kg only one adult worm died.

REPRODUCTION

The second lowest test concentration showed slight stimulation of reproduction. The other tested concentrations showed inhibition of reproduction ranging from 14.9 to 24.4% compared to the control. The inhibition of juvenile production did not increase regularly and a high variability was observed. Nevertheless, inhibition of juvenile production was less than 50% in all treatments. Therefore, the EC50 is higher than the highest tested concentration. Due to the irregularity of the dose-response curve, a determination of an EC10 was not possible. For offspring number and weight, NOEC and LOEC was calculated.

Validity criteria fulfilled:

yes

Remarks:

For further details please refer to “Any other information on results incl. tables”.

Description of key information

NOEC (56d) = 171 mg/kg dry soil (Eisenia andrei, OECD 222)

Additional information

One study investigating the long-term toxicity of N-methyl-N-(C18-(unsaturated)alkanoyl)glycine (EC 701-177-3) to soil macroorganism (Eisenia andrei) is available. This study was carried out according to OECD 222 and GLP using 5 concentrations ranging from 95 to 1000 mg/kg dry soil (95, 171, 309, 555 and 1000 mg/kg dry soil). The three highest test concentrations (309, 555 and 1000 mg/kg dry soil) showed inhibition of reproduction ranging from 14.9 % to 24.4 % compared to the control. A NOEC (56d) = 171 mg/kg dry soil was determined.