Ecotoxicities of emulsifiable concentrate and granules of cinnamon (Cinnamomum zeylanicum) essential oil against cyprinus carpio and danio rerio

In this study, cinnamon essential oil (CEO) was formulated as emulsifiable concentrate (EC) and a granule. For the evaluation of their negative effects on the ecosystem, acute toxicities against Cyprinus carpio was determined in a static condition. The formulations were made using CEOs extracted by 3 different methods (steam distillation (SD), solvent extraction and supercritical fluid extraction (SFE)) and were tested to obtain LC₅₀ values. Among the ECs, EC including CEO extracted by SFE showed highest acute toxicity against C. carpio. Among the granules, a granule including CEO extracted by SD showed highest acute toxicity against C. carpio. Nevertheless, LC₅₀ of EC and a granule formulation with CEOs was higher than toxicity level III of pesticide standardized by Korea rural development administration. These results were similar to those using zebrafishes. Chronic toxicities were not found for 45 days in zebrafishes until 500 µgL⁻¹ level of EC formulation including CEO obtained by the SD. Based on these results, EC formulation of CEOs may be considered to be used as environmental-friendly natural insecticides in accordance with the standards.