Sodium dimethyldithiocarbamate

Toxicity to soil macroorganisms except arthropods

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to soil macroorganisms except arthropods: short-term

Type of information:

experimental study

Adequacy of study:

key study

Study period:

20 August 2007 - 18 September 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)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Vehicle:

no

Details on preparation and application of test substrate:

- The test item was dissolved in deionised water in order to create a stock solution, from which different dosage solutions were derived. 100 mL of each dosage solution were added and mixed in the artificial soil.

Test organisms (species):

Eisenia fetida

Animal group:

other: Annelids, Lumbricidae

Details on test organisms:

TEST ORGANISM
- Common name: Eisenia fetida
- Source: Earthworms were originally supplied by Co. Landenberger (D-72355 Schömberg). They were kept at ECT Oekotoxikologie GmbH since February 1994.
- Weight at test initiation: Only adult worms (with clitellum) with a fresh weight between 300 and 600 mg were used



ACCLIMATION
- Acclimation period: Selected test animals were acclimatised in untreated artificial soil at least 24 hours prior to the start of the test.

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

no

Total exposure duration:

14 d

Test temperature:

18 - 22°C

pH:

6.0 to 6.6

Moisture:

55.5 – 61.1 %

Details on test conditions:

TEST SYSTEM
- Test container (material, size): 1.5 L preservation jars (“Tulpenform”), Co. Weck, Wehr-Öflingen, covered by glass lids.
- Amount of soil or substrate: Per test beaker, 500 g dry artificial soil
- 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 (if soil)
- Composition (if artificial substrate):
- 10 % Sphagnum peat (no visible plant remains, finely ground and air-dried);
- 20 % Kaolin-Clay (kaolinite content > 30 %)
- 68 – 69 % Quartz sand (fine sand content with particles between 50 and 200 µm higher than 50 %)
- ca. 1 % calcium carbonate (CaCO3)
The pH value was adjusted to 6 ± 0.5 using calcium carbonate. The moisture content was adjusted to 40 – 60 % of the maximum water capacity using deionised water. The water content of the artificial soil was determined by drying a small sample at 105 ºC.

OTHER TEST CONDITIONS
- Photoperiod and Light intensity: Continuous light (475 - 687 Lux)

EFFECT PARAMETERS MEASURED: Mortality, biomass, morphology and behaviour.

Nominal and measured concentrations:

Nominal (specified in a previous range-finding test): 10, 31.6, 100.0, 316.0 and 1000.0 mg a.s./kg soil (dw) corresponding to 24.5, 77.5, 245.1, 774.5 and 2451.0 mg test item/kg soil (dw).

Reference substance (positive control):

yes

Remarks:

chloroacetamide

Duration:

14 d

Dose descriptor:

LC50

Effect conc.:

787.6 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mortality

Remarks on result:

other: 312.5 - 1985.34

Results with reference substance (positive control):

- Results with reference substance valid? yes
- Relevant effect levels: LC50= 29.2 mg/Kg soil dw

Validity criteria fulfilled:

yes

Conclusions:

Validity criteria according to the OECD guideline 207 are fulfilled, test results can be considered reliable. A 14d-LC50 of 787.6 mg a.s./kg soil (dw) was obtained.

Executive summary:

Materials and methods: The objective of this study was the estimation of the acute toxicity of SDDC to the earthworm, Eisenia fetida. Earthworms were exposed to a range of concentrations (24.5, 77.5, 245.1, 774.5 and 2451.0 mg test item / kg dry weight of soil) of the test item in formulated soil over a 14 day period according to OECD guideline 207. Mortality, biomass, morphology and behaviour were assessed after 7 and 14 days and the LC50 (median lethal concentration) estimated.

Chloroacetamide was used as reference item as recommended for acute earthworm toxicity tests.

Results and discussion: No mortality was observed at the control. 5 % mortality was determined at the lowest concentration tested (10.0 mg a.s./kg soil (dw) corresponding to 24.5 mg test item/kg soil (dw)). At the concentrations of 31.6, 100.0 and 316.0 mg a.s. /kg soil (dw) (corresponding to 77.5, 245.1 and 774.5 mg test item /kg soil (dw)) 17.5 %, 37.5 % and 27.5 % mortality was observed, respectively. At the highest tested concentration (1000.0 mg a.s./kg soil (dw) corresponding to 2451.0 mg test item /kg soil (dw)) 55 % mortality was observed.

The biomass of individual adults after 14 days amounted to 112 % of the initial weight in the control. In the lowest test item concentration tested (10.0 mg a.s./kg soil (dw) corresponding to 24.5 mg test item/kg soil (dw)) the biomass reached 90.4 % of the initial weight and in the second lowest concentration (31.6 mg a.s./kg soil (dw) corresponding to 77.5 mg test item/kg soil (dw) it was 72.6 %. In the three highest concentrations of the test item (100.0, 316.0 and 1000.0 mg a.s./kg soil (dw) corresponding to 245.1, 774.5 and 2451.0 mg test item/kg soil (dw)) the biomass amounted 62.6 – 64.2 % of the initial weight.

Reference 2

Endpoint:

toxicity to soil macroorganisms except arthropods: long-term

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Description of key information

The chemical safety assessment carried out according to Annex I of Regulation (EC) No 1907/2006 does not indicate the need to further investigate the long-term toxicity to soil macroorganisms.

Additional information

In accordance with column 2 of REACH Annex X, a long-term study on the toxicity of sodium dimethyldithiocarbamate (CAS 128-04-1) to soil macroorganisms is not proposed based onthe chemical safety assessment carried out according to Annex I of Regulation (EC) No 1907/2006, which does not indicate the need to further investigate the long-term toxicity to soil macroorganisms.

Based on the available experimental data for the short-term terrestrial toxicity of sodium dimethyldithiocarbamate, earth worms do not represent the most sensitive trophic level for terrestrial toxicity. Furthermore, the Risk Characterization Ratio (RCR = PEC/PNEC) based on the available studies is < 1.0, indicating a low risk to soil orgsanisms.

Moreover, sodium dimethyldithiocarbamate is readily biodegradable according to OECD criteria and is characterized by a low adsorption coefficient (log Koc = -0.12) and a low partition coefficient (log Kow = -3.5 to -2.33), indicating a very low potential for adsorption to particles in soil and sediment and a low potential for bioaccumulation. Thus, chronic exposure of soil macroorganisms is highly unlikely and the substance falls into the soil hazard category 2 (Guidance R7c, Table R.7.11-2, ECHA, 2017), according to which no long-term testing is necessary.