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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Short-term toxicity to aquatic invertebrates

Read across to the Benzoic acid: OECD 202, Daphnia magna, static, EC50(48h): 7.04 (6.25–7.85) mmol/L, i.e. 860 mg/L.

Read across to DMTD: OECD 202, GLP compliance, Daphnia magna, static, EC50(48h): 5.95 mg/L


Toxicity to aquatic algae and cyanobacteria

Read across to DMTD: OECD 201, GLP compliance, Desmodesmus subspicatus (previous name: Scenedesmus subspicatus), static, EC50 (72h, growth rate): > 160 mg/L, NOEC(72h) 20mg/L, EC10(72h, growth rate): 32.86 mg/L 

Read across to Benzoic acid: OECD 201, cyanobacteria (blue-green algae) Anabaena inaequalis, A. cylindrica, and A. variabilis, green algae Chlorella pyrenoidosa and Scenedesmus quadricauda, static, EC50 (12-14d): > 10 mg/L

Read across to Benzoate: Scenedesmus quadricauda, LOEC (96h, growth rate): 1630 mg/L


Additional information

The substance 5-mercapto-1,3,4-thiadiazole-2-thiol-benzoate is known to hydrolyse in aqueous solutions.Thus, a hydrolysis test was performed and hydrolysis products were identified in an OECD 111 Guideline study. 1,3,4-Dimercapto-thiadiazol (DMTD, CAS 1072-71-5) and benzoic acid (CAS 65-85-0) were identified as degradation products, where the parent compound's half life was 1.19 h. Therefore data on aquatic toxicity of the hydrolysis products were used in a weight-of-evidence approach. 

The acute toxicity values for DMTD in an OECD 202 study with Daphnia magna of EC50(48h) 5.95 mg/L and in an OECD 201 study with Desmodesmus subspicatus of ErC50(72h) > 160 mg/L were below the acute toxicity values in daphnia for benzoic acid of EC50(48h) 860 mg/L  and in algae for benzoate of 1630 mg/L, respectively. The lower values of DMTD have been used for hazard evaluation leading to the conclusion "not classified for aquatic toxicity".


Based on the results of the hydrolysis products the registered substance does not need to be classified as toxic to aquatic environment, neither acute nor chronic, according to Regulation (EC) No 1272/2008.