Octane-1-thiol

Short-term toxicity to aquatic invertebrates

Description of key information

MOE (2004): The 48 hour toxicity of octane-1-thiol to daphnia is LC50: 0.0243 mg/l and NOEC: 0.0037 mg/L.
Thiebaud (1995): The 48 hour EC50 are lower than the limit of solubility of the substance and therefore may potentially be harmful. However, the limit of solubility is below the limit of analysis and thus the EC50 could not be calculated but was estimated to be 0.42 mg/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.024 mg/L

Additional information

A summary of MOE (2004) is only available for this report and so it has not been fully evaluated. This study is used as a critical study for the SIDS endpoint and is used in the IUCLID Data Set for Octane-1-thiol (2004). The study has been given a Klimisch score 1 - reliable without restrictions (Klimisch et al, 1997) in the IUCLID Data Set and is here considered as Klimisch 1 untill the reference is available as being sponsored by MOE one can consider the study as relevant.

Thiebaud (1995) is a GLP-compliant study following OECD guideline 202. The study was conducted on a substance of low water solubility, but it was chosen not to use an external solvent. Due to the low water solubility of the substance, the EC50 could not be determined precisely. It is unknown whether the test met the validity criteria; the limit of analysis was above the concentrations of the test substance and it was not possible to determine whether concentrations were maintained within 80% of the nominal concentrations though precautions were taken to minimise volatilisation.

Both of these results would lead to octane-1 -thiol being classified as very toxic to aquatic organisms under DSD and acute category 1 under CLP. The MOE result has been chosen as the lead as the value is the more conservative result.