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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

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Description of key information

The results of the key study (CERI, 2000) show there is no effect within 48h on Daphnia magna at concentrations greater than the solubility limit (0.056 to 0.0165 mg/L). For other studies used as supporting evidence similar results were found that support the evidence that little adverse effect is observed up to the limit of solubility.

Key value for chemical safety assessment

Additional information

The key study (CERI, 2000) was a GLP study following EU method C2 where daphnids were exposed to the substance in DMSO. The study was performed open but concentrations were measured and therefore the study is considered reliable and suitable for use. Effects were measured only at the highest concentration of 0.1 mg/L nominal. In the second highest concentration of 0.056 mg/L nominal measured at 0.0165 at test start to 0.00546 mg/L at test end) no effects were observed.

(Thiebaud, 1997) is a static GLP study following EU method C2 but as the analytical method was too insensitive to determine the concentrations used the study cannot be considered valid but is included as supporting evidence.

Cowgill performed a supporting study documented in a publication detailing a semi-static study on Ceriodaphnia, following a method similar to that of OECD guideline 202. The report is detailed and the study follows standard scientific practices but as it was conducted in an open system without analysis it cannot be considered reliable. The DOW (1990) study is an open, static, 48 hour study with reference substance, following standard US EPA methods. However, this can only be used as a supporting study as the acetone vehicle was above OECD guideline limits (500 µL/L), no analysis was performed and all nominal concentrations of tert-dodecanethiol were above the water solubility limit. The Jenkins (1990) study was a static, 48 hour test on Daphnia magna. It did not follow OECD guidelines, but was conducted according to a study protocol (PTS9). No analytics were included and effects occurred only at concentrations nominally far greater than the solubility limit.

Three further endpoint values were located from other studies and these are documented in the review by Thomas & Comber (2013). Only the 24 h EC50s were determined and all values were >0.25 mg/L but insufficient information was available to prepare an endpoint summary and they have not been included in the IUCLID.

Based on the above information it can be concluded that none of the studies resulted in an EC50 at less than or at the water solubility limit of the substance.