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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

The acute EC50 for algae of wash oil (composite sample No. 05) itself was found to be 25 mg/L, based on the loading, EL50.  
In a separate study using acenaphthene, the EC10 was 38 µg/L, based on measured concentrations of acenaphthene as a key component of wash oil.

Key value for chemical safety assessment

EC50 for freshwater algae:
25 mg/L
EC10 or NOEC for freshwater algae:
38 µg/L

Additional information

Data on toxicity to aquatic algae are available for creosote oil, acenaphthene fraction itself as well as for the wash oil components acenaphthene (marker substance, see Chapter 7.1,) and fluorene. Hence, data for wash oil and for acenaphthene and fluorene are presented.

For wash oil composite sample No. 05, a 72-h NOELR (No-observed-effect-loading rate) of 10 mg/L nominal (corresponding EL50: 25 mg/L) on unicellular freshwater green algae Desmodesmus subspicatus was observed under open test conditions in a static test system (Aniol et al. 2007). Concentration of dissolved material in the aqueous solutions (WAF) were determined to be ca. 2 mg TOC/L for the 10 mg/L loading and ca. 7 mg TOC/L for the 50 mg/L loading.

No values for marine organisms are available.

The 72-h EC10 values concerning biomass and growth rate are reported for acenaphthene (marker substance) and fluorene as basic component of wash oil. The analytical values were 38 and 82 µg/L, respectively, based on measured concentrations and were determined on the freshwater green alga Pseudokirchneriella subcapitata in a static test system (Bisson et al., 2000). Toxicity of acenaphthene to freshwater green algae was higher than that of fluorene.

As already observed for fish short-term toxicity, toxicity determined for wash oil as whole is considerably lower than toxicity of individual wash oil constituents.