long chain alkyl thio carbamide metal complex

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:

01 November to 16 November 2007

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

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: all control and test groups
- Sampling method: no data
- Sample storage conditions before analysis: no data

Vehicle:

yes

Details on preparation and application of test substrate:

- Method of mixing into soil (if used): solution of test substance in THF coated onto aliquot of dry soil by rotary evaporation and spiked soil mixed into bulk soil
- Controls: solvent and negative
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): tetrahydrofuran (THF)
- Concentration of vehicle in test medium (stock solution and final test solution): no data
- Evaporation of vehicle before use: yes

Test organisms (species):

Eisenia fetida

Animal group:

annelids

Details on test organisms:

TEST ORGANISM
- Common name: earthworm
- Source: in-house from worms obtained from the University of Maryland, Queenstown, Md USA
- Age at test initiation (mean and range, SD): adult (with clitellum)
- Weight at test initiation (mean and range, SD): range 0.52 to 0.58 g

ACCLIMATION
- Acclimation period: 24 h
- Acclimation conditions (same as test or not): yes
- Health during acclimation (any mortality observed): none

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

no

Total exposure duration:

14 d

Post exposure observation period:

none

Test temperature:

At initiation: 19.7 to 20.3oC
At termination: 19.0 to 19.2oC

pH:

At test initiation: 6.4 to 6.6
At termination: 7.9

Moisture:

At initiation: 32.9 to 33.3%
At termination: 31.1 to 32.1%

Details on test conditions:

TEST SYSTEM
- Test container (material, size): 1 L glass beaker
- Amount of soil or substrate: 750 g
- 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)
- Composition (if artificial substrate): quartz sand (approx. 70%); kaolin clay (approx. 20%); sphagnum peat (approx. 10%) plus CaCO3 (1%)
- Organic carbon (%): 3.9
- Maximum water holding capacity (in % dry weight): no data
- Pretreatment of soil: none
- Storage (condition, duration): none
- Stability and homogeneity of test material in the medium:
- stability: mean recovery at day 14 - 103%, 96% and 96% at low, middle and high concentrations
- homogeneity: mean ± SD (CV) at lowest conc - 59.8 ± 0.839 (1.4%); at highest conc - 944 ± 27.6 (2.93%)

OTHER TEST CONDITIONS
- Photoperiod: continuous illumination
- Light intensity: 400-800 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : day 0 - body weight, burrowing behaviour, mortality; day 7 and 14 - mortality, behaviour and structural abnormalities; day 14 - body weight

VEHICLE CONTROL PERFORMED: yes

TEST CONCENTRATIONS
- Spacing factor for test concentrations: x2
- Justification for using less concentrations than requested by guideline: not applicable

Nominal and measured concentrations:

nominal: 62.5, 125, 250, 500 and 1000 mg/kg dry weight soil
measured: 59.8, 118, 253, 484 and 944 mg/kg dry weight soil

Reference substance (positive control):

yes

Remarks:

but in a separate study

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:

behaviour

Details on results:

- Mortality at end of exposure period: No mortalities in the controls, or treatment groups other than one earthworm not found (presumed dead) in the 250 mg/kg (nominal) treatment group, which was not considered treatment related.
- Changes in body weight of live adults at end of exposure period: weight loss varied from 0.12 g (negative control) to 0.06 g (1000 mg/kg group). This slight loss of body weight in the control and treatment groups was not unexpected since the earthworms were not fed during the test.
- No. of offspring produced: no data
- No. of unhatched cocoons: no data
- Morphological abnormalities: none
- Behavioural abnormalities: none
- Other biological observations: none

Results with reference substance (positive control):

- Results with reference substance valid? yes
- Relevant effect levels: LC50 - 24.5 mg a.i/kg dry soil for chloroacetamide

Reported statistics and error estimates:

Body weight data - Dunnett's 2-tailed test of means (alpha=0.05) after data tested for homogeneity of variance and normal distribution.

Validity criteria fulfilled:

yes

Conclusions:

In a GLP study conducted according to OECD guideline 207, no treatment-related mortality, or adverse effects on body weight change, appearance and behaviour were seen in earthworms (Eisenia fetida) exposed to EC#457-320-2 in artificial soil for 14 days at up to nominal concentrations of 1000 mg/kg dry weight soil (considered the NOEC in this study). The 14-day LC50 is therefore greater than 1000 mg EC# 457-320-2/kg dry wt soil.

Executive summary:

In a GLP study conducted according to OECD guideline 207, the acute toxicity to earthworms (Eisenia fetida) of EC# 457-320-2 (with a molybdenum content of about 10%) has been determined following exposure for 14 days in artificial soil. Animals were exposed to nominal concentrations of 62.5, 125, 250, 500 and 1000 mg EC# 457-320-2/kg dry wt of soil and examined for mortality, body weight change, appearance and behaviour after 7 and 14 days. The potential uptake of the test material over the course of the study was also assessed.

In the treatment groups, only one death was seen on day 7 in an earthworm exposed to 250 mg EC# 457-320-2/kg dry wt soil, which was not considered to be treatment-related. No mortality was seen in the control groups during the study. No adverse effects were seen on behaviour or appearance in any control or treatment groups during the study. A reduction in mean body weight was seen at day 14 in all groups, but this was not unexpected as animals were not fed during the experimental period. Analysis of the earthworms on day 14 of the study showed that tissue levels of molybdenum were below the limit of quantitation of the analytical method.

No treatment-related mortality, or adverse effects on body weight change, appearance and behaviour were seen in earthworms (Eisenia fetida) exposed to EC# 457-320-2 in artificial soil for 14 days at up to nominal concentrations of 1000 mg/kg dry wt soil; considered the no-observed-effect concentration (NOEC) in this study. The 14-day LC50 is therefore greater than 1000 mg/kg dry wt soil. Earthworms did not accumulate EC# 457-320-2, measured as molybdenum content, over the study period.

Description of key information

The 14-day NOEC in earthworms was 1000 mg/kg dry wt soil; the 14-day LC50 was >1000 mg/kg dry wt soil.

Key value for chemical safety assessment

Short-term EC50 or LC50 for soil macroorganisms:

1 000 mg/kg soil dw

Additional information

One toxicity to soil macroorganisms except arthropods study is available for EC# 457-320-2: a 14-day acute study in earthworms, conducted to GLP and in accordance with OECD Test Guideline 207. The earthworms were exposed to artificial soil spiked with EC# 457-320-2 test material (with a molybdenum content of approximately 10%) at nominal concentrations of 0, 62.5, 125, 250, 500 and 1000 mg EC# 457-320-2/kg dry weight of soil.

There were no treatment-related deaths or effects on appearance, behaviour or body weight. Analysis of the earthworms on day 14 of the study showed that tissue levels of molybdenum were below the limit of quantitation of the analytical method. The NOEC was concluded to be 1000 mg/kg dry wt soil; the LC50 was >1000 mg/kg dry wt soil.