Emprego de microalgas para remoção dos inseticidas Bifentrina e Imidacloprido em águas.

Abstract

The accumulation of pesticides in the environment and can cause problems to aquatic ecosystems and also cause adverse effects for humans and the environment These compounds can be found in water due to runoff when used in agriculture, industrial and domestic applications. Bifenthrin and imidacloprid were studied due to their toxicity degree (degree II) in relation to the environment and organisms and also in its use in tobacco culture. The phycoremediation was proposed as an environmental alternative for the remediation of water courses contaminated with insecticides. The microalgae were reproduced from Santa Cruz do Sul’s water reservoir (Lago Dourado). For that, the biodegradation, biosorption, pH influence, inoculum percentage and photoperiod were evaluated in experiments carried out on a batch during 20 days of cultivation. After the phycoremediation process, bifenthrin insecticide (m/z = 181) was quantified by GC-MS and imidacloprid using HPLC-DAD (λ = 270 nm). The microalgae reproduced from the lake’s water were capable to aid in the removal of approximately 99% of bifenthrin and 26% of imidacloprid through biodegradation and biosorption processes. For bifenthrin the best phycoremediation condition was 20% of inoculum and photoperiod 18:6 h and for imidacloprid, 10% of inoculum and photoperiod 12:12 hour, both without pH control.