Di(benzothiazol-2-yl) disulphide

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:

April 2017 - July 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))

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Remarks:

Visual inspection; weighing

Details on sampling:

Mortality and biomass after 28 days; reproduction after 56 days;

Vehicle:

no

Details on preparation and application of test substrate:

10 Eisenia fetida per test vessel;
Exposure: Mixed with artificial soil;
The worms were introduced into the test vessels after the contaminated artificial soil was placed into the test vessels. The test animals were exposed to the test item by dermal and alimentary uptake.
The method of administration follows the requirements of the test guideline.

Test organisms (species):

Eisenia fetida

Animal group:

annelids

Details on test organisms:

The earthworms used in this test, Eisenia fetida (Lumbricidae, Earthworms) have been kept at ECT Oekotoxikologie GmbH since February 1994. They were originally delivered by Co. Landenberger (72355 Schömberg, Germany).
Only adult earthworms (with clitellum) with a fresh weight (FW) between 300 and 600 mg were used. The earthworms were at least two months, but not more than one year old. However, the age of individuals did not differ by more than four weeks. Animals which fulfilled these requirements were taken from a synchronised culture. The earthworms selected for the test were acclimatised in artificial soil under test conditions for at least 24 hours before starting the test.

Study type:

laboratory study

Substrate type:

artificial soil

Remarks:

Artificial soil with 5% peat (With respect to the properties of the test item (log Pow≥2), considering the influence on bioavailability, 5% instead of 10% peat were used (EPPO 2003).)

Limit test:

no

Total exposure duration:

28 d

Remarks:

The test item was applied once at the beginning of the test. The duration of the test period (exposure of earthworms to the artificial soil containing the test item) was 56 days. The adult worms were removed from the substrate after 28 days.

Post exposure observation period:

The number of juveniles was determined after 56 days after application.

Test temperature:

Temperature: 18.6–20.7 °C (recommended 20±2 °C)

pH:

Soil pH-value (day 0): 6.0 (recommended 6±0.5),
Soil pH-value (day 56): 6.5–6.7

Moisture:

Soil moisture (day 0): 48.0–51.2% of the WHCmax (rec. 40–60%),
Soil moisture (day 56): 64.9–75.2% of the WHCmax;

Details on test conditions:

The earthworms were tested in an artificial soil. The composition of this artificial soil was based on OECD Guideline No. 222 (2016) (the percentages refer to the dry weight):
- 5% Sphagnum peat (no visible plant remains; finely ground and air-dried)
- 20% Kaolin clay (kaolinite content >30%)
- 74–75% Quartz sand (fine sand content with particles between 50 and 200 μm higher than 50%)
- 0.3–1% Calcium carbonate (CaCO3).

Nominal and measured concentrations:

62.5, 125, 250, 500 and 1000 mg test item/kg artificial soil dry weight (dw);

Reference substance (positive control):

yes

Remarks:

150, 300 and 600 mg Boric acid/kg (separate GLP study)

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

>= 1 000 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Duration:

28 d

Dose descriptor:

LOEC

Effect conc.:

> 1 000 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

>= 1 000 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: biomass

Duration:

28 d

Dose descriptor:

LOEC

Effect conc.:

> 1 000 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: biomass

Duration:

56 d

Dose descriptor:

NOEC

Effect conc.:

>= 1 000 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Duration:

56 d

Dose descriptor:

LOEC

Effect conc.:

> 1 000 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Results with reference substance (positive control):

150, 300 and 600 mg Boric acid/kg (separate GLP study):
In a separate GLP study (ECT study number IRR1703) Eisenia fetida were exposed to Boric acid at nominal concentrations of 150, 300 and 600 mg boric acid/kg artificial soil (dw). According to the ISO guideline 11268-2 Part 2 (2011) a significant effect on reproduction should be observed between 400 and 600 mg boric acid/kg soil dry weight (dw). Concerning number of juveniles statistical analysis (William’s t-test, p = 0.05, one-sided) showed a significant difference between the control and the concentrations of 300 and 600 mg boric acid/kg soil (dw). Since this observed effect is slightly higher than mentioned in the ISO guideline the effects of boric acid confirm suitable sensitivity of the test system.

The effects of the test item MBTS on mortality, biomass development, morphological changes and reproduction to the earthworm Eisenia fetida in artificial soil were tested in the laboratory. At concentrations up to and including 1000 mg test item/kg soil dry weight the test item had no adverse effects on either mortality, biomass development, morphological changes and reproduction to the test species.

Validity criteria fulfilled:

yes

Conclusions:

MBTS shows a NOEC of >= 1000 mg test item / kg soil dw and the derived LOEC is considered to be >1000 mg test item / kg soil dw for either mortality, biomass and reproduction as basis of effect.
Conclusively, MBTS shows no toxic chronic effects on terrestrial invertebrates.

Executive summary:

The long-term effects of MBTS on mortality, biomass development, morphological changes and reproduction to the earthworm Eisenia fetida in 5% artificial soil were tested in the laboratory according to OECD Guideline No. 222. At concentrations up to and including 1000 mg test item/kg soil dry weight the test item had no adverse effects on either mortality, biomass development, morphological changes and reproduction to the test species (ECT 2017). The derived NOEC is considered to be >= 1000 mg test item / kg soil dw and the derived LOEC is considered to be >1000

mg test item / kg soil dw for either mortality, biomass and reproduction as basis of effect.

Conclusively, MBTS shows no toxic chronic effects on terrestrial invertebrates.

Description of key information

The long-term effects of MBTS on mortality, biomass development, morphological changes and reproduction to the earthworm Eisenia fetida in 5% artificial soil were tested in the laboratory according to OECD Guideline 222. At concentrations up to and including 1000 mg test item/kg soil dry weight the test item had no adverse effects on either mortality, biomass development, morphological changes and reproduction to the test species (ECT 2017). The derived NOEC is considered to be >= 1000 mg test item / kg soil dw and the derived LOEC is considered to be >1000 mg test item / kg soil dw for either mortality, biomass and reproduction as basis of effect. Conclusively, MBTS shows no toxic chronic effects on terrestrial invertebrates.