N-phenyl-N-[(trichloromethyl)thio]benzenesulphonamide

Toxicity to soil microorganisms

Administrative data

Endpoint:

toxicity to soil microorganisms

Type of information:

experimental study planned

Justification for type of information:

TESTING PROPOSAL ON TERRESTRIAL MICROORGANISMS, OECD 216

NON-CONFIDENTIAL NAME OF SUBSTANCE:
- Name of the substance on which testing is proposed to be carried out: N-phenyl-N-[(trichloro-methyl)thio]benzene-sulphonamide (CAS 2280-49-1)

CONSIDERATIONS THAT THE GENERAL ADAPTATION POSSIBILITIES OF ANNEX XI OF THE REACH REGULATION ARE NOT ADEQUATE TO GENERATE THE NECESSARY INFORMATION:
- Available GLP studies: For N-phenyl-N-[(trichloro-methyl)thio]benzene-sulphonamide (CAS 2280-49-1) no studies assessing the toxicity on terrestrial microorganisms are available yet.
- Available non-GLP studies: No further studies on terrestrial toxicity on microorganisms are available for N-phenyl-N-[(trichloro-methyl)thio]benzene-sulphonamide (CAS 2280-49-1)
- (Q)SAR: There are no QSAR models available for this higher tier ecotoxicological endpoint that are sufficiently validated and acceptable (according to OECD Q/SAR validation criteria).
- Weight of evidence & Grouping and read-across: N-phenyl-N-[(trichloro-methyl)thio]benzene-sulphonamide (CAS 2280-49-1) is not part of a category and no data on terrestrial toxicity on microorganisms for N-phenyl-N-[(trichloro-methyl)thio]benzene-sulphonamide (CAS 2280-49-1) or related substances is available. There is thus no data supporting a weight of evidence or read-across approach and further testing is deemed necessary.

CONSIDERATIONS THAT THE SPECIFIC ADAPTATION POSSIBILITIES OF ANNEXES VI TO X (AND COLUMN 2 THEREOF) OF THE REACH REGULATION ARE NOT ADEQUATE TO GENERATE THE NECESSARY INFORMATION:
- As described in REACH Guidance document R7.c, Version 3.0 (June 2017) soil hazard category 3 applies for N-phenyl-N-[(trichloromethyl)thio]benzenesulphonamide: The substance is not readily biodegradable. There is no indication that the substance is very toxic to aquatic organisms. The experimentally determined partition coefficient (logKOW: 4.7) and the soil adsorption coefficient (logKOC: 4.5) are both indicative for an adsorptive potential of the substance.
According to Table R.7.11-2 soil category 3 requests to apply the EPM approach as well as to conduct a confirmatory long-term soil toxicity study. For N-phenyl-N-[(trichloromethyl)thio]benzenesulphon-amide it is, however, not possible to apply the EPM approach as no effects were determined in acute and chronic studies up to the limit of water solubility. The conclusion in accordance with REACH Guidance Document R.10 was, therefore, “no hazard identified” and no PNEC aqua was derived. In order to fulfill the requirements according to Table R.7.11-2, a confirmatory long-term toxicity test for terrestrial invertebrates according to OECD TG 222 Earthworm Reproduction Test was conducted and used to calculate the PNEC soil. The trophic level of invertebrates was investigated as it was considered as most relevant.
Recent experimental results from an earthworm reproduction test indicate toxicity of N-phenyl-N-[(trichloromethyl)thio]benzenesulphonamide towards the terrestrial compartment. It is therefore required to assess the toxicity towards other terrestrial compartments. According to REACh Regulation (EC) No. 1907/2006, Annex IX, 9.4, column 2 and ECHA Guidance R.7c (2017), long-term terrestrial studies are recommended for compounds with high potential for adsorption to soil.
The registrant has carefully considered the available adaptation possibilities applicable for the discussed endpoint. Based on the lack of data on toxicity testing on terrestrial plants and the recommendations in ECHA Guidance R.7c (2017), it is deemed necessary to further investigate the long-term toxicity potential of the substance.

FURTHER INFORMATION ON TESTING PROPOSAL IN ADDITION TO INFORMATION PROVIDED IN THE MATERIALS AND METHODS SECTION:
- The registrant intends to perform the toxicity on soil microorganisms according to OECD TG 216, Soil Microorganisms: Nitrogen Transformation Test. According to the guideline, the study design of this study will fit to the physico-chemical properties of the test substance, as this study can deal with substances with low water solubility and prone to hydrolysis.

Materials and methods

Test guideline

Guideline:

OECD Guideline 216 (Soil Microorganisms: Nitrogen Transformation Test)

Test material

Test material information

Constituent 1

Reference substance name:

N-phenyl-N-[(trichloromethyl)thio]benzenesulphonamide

EC Number:

218-915-0

EC Name:

N-phenyl-N-[(trichloromethyl)thio]benzenesulphonamide

Cas Number:

2280-49-1

Molecular formula:

C13H10Cl3NO2S2

IUPAC Name:

N-phenyl-N-[(trichloromethyl)sulfanyl]benzenesulfonamide

Specific details on test material used for the study:

Test material with a high degree of purity will be used.