Egeria densa remediates the aquatic environment and reduces 14C-deltamethrin bioaccumulation in Danio rerio.

Deltamethrin is an insecticide with high toxicity to non-target aquatic organisms. Environment-friendly alternatives to removing insecticides from water bodies, like phytoremediation, require species to uptake and/or dissipate pesticides from water. Our research investigated the ability of Egeria densa plants to absorb and dissipate ¹⁴C-deltamethrin from water, and bioaccumulation in Danio rerio. The variables were four densities of E. densa (0, 234, 337, and 468 g dry weight m^-3), in tanks with seven adults of D. rerio, with three replicates. Dissipation was evaluated at 0, 24, 48, 72, and 96 h after application (HAA). After 96 HAA, the uptake of ¹⁴C-deltamethrin by plants and accumulation in fish were assessed. The E. densa increased ¹⁴C-deltamethrin dissipation and reduced bioaccumulation in zebrafish. The DT₅₀ decreased 3-fold in treatments with 337 and 468 g m^-3 of E. densa. The plants absorbed 32% of the ¹⁴C-deltamethrin applied, regardless of plant density. The bioaccumulation in fish was 8.21% without E. densa and only 1% in treatments with 468 g m^-3 of plants. These results suggest phytoremediation using E. densa is a possible alternative to removing deltamethrin from water and reducing the accumulation in non-target organisms, reducing the environmental impact of insecticides in aquatic ecosystems.