Calcium 1,4-bis(2-ethylhexyl) bis(2-sulphosuccinate)

Endpoint summary

Description of key information

No data are available for the registered substance, however data are available for the corresponding sodium salt of the substance, docusate sodium (CAS 577-11-7). These data are used for read-across to the registered substance calcium docusate (CAS 128 -49 -4). The presence of either of the counterions sodium or calcium is not considered to have an impact on the toxicity. It is therefore considered justified to use the data of the sodium salt for read across to the calcium salt of docusate.

Additional information

The environmental hazard assessment for (fresh-) water organisms and sediment habitats is supported by several acute studies (pelagic compartment), a chronic Daphnia reproduction study and by using scientific argumentation (sediment dwelling organisms). The data and conclusions summarised in this section for docusate sodium are considered to be valid for the registered substance (docusate calcium).

For the environmental hazard assessment of Docusate calcium acute toxicity studies for the read-across analogue docusate sodium are available for freshwater fish, daphnids, freshwater algae and STP microorganisms. In addition, a long-term Daphnia reproduction study is available. A long-term study for fish is waived since a longtern study is available for the more sensitive group, e.g., the daphinds. Experimental information about toxicity on marine organisms is not available.

Some of the above studies were conducted with test materials which contained the submission substance at > 80%. The majority of the acute aquatic studies, however, was performed with Docusate Sodium containing formulations. These test materials contained typically between 64 and 70 % Docusate Sodium. For the assessment of all available studies it was assumed that neither synergistic nor antagonistic effects influence the toxicity of Docusate Sodium and - as worst case scenario - the toxicity observed for the test material is only due to the toxicity of Docusate Sodium. The concentration of Docusate Sodium in the respective test materials was used to calculate the effect concentrations for Docusate Sodium.

The short-term EC50/LC50 values for fish, Daphnia, algae and microorganisms were 49, 15.2, 82.5 and 164 mg Docusate Sodium/L, respectively. The EC10 (mortality) obtained in a 21 day chronic daphina reproduction study was 9.0 mg/L. The reproduction of Daphnia was not affected at concentrations up to 11 mg/L, a concentration at which mortality was relevant.

Docusate calcium is expected to be ready biodegradable and (despite the QSAR predictions) is expected to have a low log Koc resulting in a low likelihood to partition to sediment and is only moderately toxic to pelagic aquatic organisms. Therefore, Docusate Calcium is not expected to cause adverse effects on sediment organisms. Consequently sediment toxicity tests do not need to be conducted to assess the risk for sediment-dwelling organisms.

The daphnids were the most sensitive trophic level with an geometric mean EC50 of 15.2 mg Docusate Sodium/L and an 21 day-EC10 (mortality) of 9.0 mg/L. This value of 9.0 mg/L will be used as worst case scenario for the risk assessment of aquatic organisms exposed to docusate calcium.