5,5'-dithiodi-1,3,4-thiadiazole-2(3H)-thione

Toxicity to soil microorganisms

Administrative data

Endpoint:

toxicity to soil microorganisms

Type of information:

experimental study planned

Justification for type of information:

According to column 2 of annexe IX of REACh regulation EC 1907/2006 "In the absence of toxicity data for soil organisms, the equilibrium partitioning method may be applied to assess the hazard to soil organisms". The exposure assessment of bis-DMTD (see Chapter 9 of the chemical safety report) based on PNECsoil(screen) does not indicate any risk for terrestrial compartment under any scenario (all RCRs to all compartments are below 1 and all the supported uses are therefore assessed to be safe)
However, in accordance with ECHA’s guidance on information requirements and chemical safety assessment, chapter R7c (v3.0 ; June 2017; pp. 154 -159),in the absence of data of toxicity to soil organisms for soil hazard category 3 substances as is the case for bis-DMTD (Non Readily biodegradable substance classified as toxic to aquatic life with long lasting effets), confirmatory long-term terrestrial toxicity testing on invertebrates and microorganisms activity must be carried out. The registrant proposes an integrated strategy where OECD 216 - which is the easiest and shorter test - is conducted first. The derived NOEC will serve as a maximum test concentration for the longer and more costly other terrestrial toxicity test. From the registrant’s experience, the NOEC of OECD 216 is very useful to narrow the range of concentrations to be tested in the other test.

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 216 (Soil Microorganisms: Nitrogen Transformation Test)

Test material

Test material information

Constituent 1

Reference substance name:

5,5'-dithiodi-1,3,4-thiadiazole-2(3H)-thione

EC Number:

276-763-0

EC Name:

5,5'-dithiodi-1,3,4-thiadiazole-2(3H)-thione

Cas Number:

72676-55-2

Molecular formula:

C4-H2-N4-S6

IUPAC Name:

5,5'-dithiodi-1,3,4-thiadiazole-2(3H)-thione

Constituent 2

Reference substance name:

S=C2CSC(=NN2)SSC1=NNC(=S)S1

IUPAC Name:

S=C2CSC(=NN2)SSC1=NNC(=S)S1

Constituent 3

Reference substance name:

(Single Anionic Charge, with the Charge Positioned on the Sulfur Atom)

IUPAC Name:

(Single Anionic Charge, with the Charge Positioned on the Sulfur Atom)

Constituent 4

Reference substance name:

(Single Anionic Charge, with the Charge Positioned on the Nitrogen Atom)

IUPAC Name:

(Single Anionic Charge, with the Charge Positioned on the Nitrogen Atom)

Constituent 5

Reference substance name:

(Double Anionic Charge, Positioned on a Single Sulfur Atom and a Single Nitrogen Atom)

IUPAC Name:

(Double Anionic Charge, Positioned on a Single Sulfur Atom and a Single Nitrogen Atom)

Constituent 6

Reference substance name:

(Double Anionic Charge, Both Positioned on Sulfur Atoms)

IUPAC Name:

(Double Anionic Charge, Both Positioned on Sulfur Atoms)

Constituent 7

Reference substance name:

S=C2SC(=NN2([Na]))SSC1=NN([Na])C(=S)S1 (Double Anionic Charge, Both Positioned on Nitrogen AtomsS

IUPAC Name:

S=C2SC(=NN2([Na]))SSC1=NN([Na])C(=S)S1 (Double Anionic Charge, Both Positioned on Nitrogen AtomsS

Test material form:

solid: particulate/powder