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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

Assessment of acute toxicity to Algae

Key value for chemical safety assessment

EC50 for freshwater algae:
100 mg/L
EC50 for marine water algae:
100 mg/L
EC10 or NOEC for freshwater algae:
100 mg/L
EC10 or NOEC for marine water algae:
100 mg/L

Additional information

The substance is a hydrocarbon UVCB of limited solubility.

The effect of the substance was assessed on algal growth using the unicellular green alga Pseudokirchneriella subcapitata, over an exposure period of 72 hours.

Because no significant inhibition of algal growth was observed during the preliminary range-finding test, a limit test was carried out using only one concentration at the solubility level of the test substance in the test medium (100 % v/v saturated solution, nominal loading rate of 100 mg/L) and one control group.

Under the conditions of this algal growth inhibition test the observed endpoints for the effect of NovaSpec EL46 were the following:

The 72h EbC50 value (biomass): > 100 mg/L loading rate WAF

The 72h ErC50 value (growth rate): > 100 mg/L loading rate WAF

The 72h EyC50 value (yield): > 100 mg/L loading rate WAF

The No-Observed Effect Concentration (NOEC): 100 mg/L loading rate WAF

The Lowest Observed Effect Concentration (LOEC): > 100 mg/L loading rate WAF

70 proposed molecules from the UVCB have also been assessed using QSAR, in order to provide a suitable range of likely values associated with the substance. These results, upon first inspection, indicate that the classification as “toxic” could apply. However, if the log Kow is greater than 5.0, or if the LC50 exceeds the water solubility by 10X, no effects at saturation are predicted. Given that the substance is insoluble in water, it is clear that the substance does not demonstrate any effects at the limit of solubility within water. This is based on the fact that this category of substances does not demonstrate any significant toxicity to aquatic organisms. No classification and labelling is proposed.