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.

Soybean seed treatment: how do fungicides translocate in plants?

BACKGROUND: Soybean seed treatment with fungicides is a well-established disease management strategy. However, the movement of these fungicides within seedlings is not always well characterized. Thus, the objectives of this study were to determine the pattern of translocation of three fungicides with different modes of action applied as a seed treatment, and the effect of soil type on translocation. RESULTS: Most of the absorbed radioactivity was concentrated in the cotyledons and the maximum sum of the rates of absorption by roots, stems, and leaves of the plants was 15%. In most cases, absorption by roots, stems, and leaves were lower than 5% for 14 C-pyraclostrobin and 14 C-metalaxyl, and 1.6% for 14 C-carbendazim. Fungicides absorbed by the roots and the whole seedlings were higher when plants were grown in soil with lower organic matter content. Fungicides in the cotyledons are unlikely to be redistributed and are lost when cotyledons fall off the plants. CONCLUSION: Cotyledons are the part of the plant where fungicides are most absorbed, regardless of the fungicide. Soil type affects the absorption of fungicides, and in this study it was most likely caused by soil organic matter. These data improve knowledge of the movement of seed treatment fungicides in soybean seedlings and may help the development of seed treatment chemistry to manage seed and soilborne pathogens.