RESUMO
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.
Assuntos
Inseticidas , Poluentes Químicos da Água , Animais , Peixe-Zebra , Inseticidas/toxicidade , Ecossistema , Bioacumulação , Poluentes Químicos da Água/toxicidade , ÁguaRESUMO
Pyrolysis conditions directly influence biochar properties and, consequently, influence the potential use of biochar. In this study, we evaluated the effects of different pyrolysis temperatures (450, 550, 650, 750, 850, and 950 °C) on the hydrogen potential, electrical conductivity, ash content, yield, volatile matter content, elemental analysis, Fourier-transform infrared spectroscopy results, X-ray diffraction results, scanning electron microscopy results, specific surface area, and micropore volume of eucalyptus wood-derived biochar. The degree of linear association between pyrolysis temperatures and biochar properties was examined using the Pearson correlation coefficient. The results showed a positive correlation of the pyrolysis temperature with the hydrogen potential value, electrical conductivity, and elemental carbon. There was a negative correlation of the pyrolysis temperature with the yield, volatile matter content, elemental oxygen, elemental hydrogen, surface area, aromaticity, hydrophilicity, and polarity indexes. The Fourier-transform infrared spectroscopy data indicated an increase in aromaticity and a decrease in the polarity of high-temperature biochar. The increased pyrolysis temperature caused the loss of cellulose and crystalline mineral components, as indicated by X-ray diffraction analysis and scanning electron microscopy images. These results indicated that changing the pyrolysis temperature enables the production of biochar from the same raw material with a wide range of physicochemical properties, which allows its use in various types of agricultural and environmental activities.
RESUMO
A infestação de plantas daninhas é um dos principais fatores bióticos presentes no agroecossistema da cana-de-açúcar que têm a capacidade de interferir no desenvolvimento e na produtividade da cultura. O trabalho teve como objetivo avaliar o potencial de lixiviação e efeito residual do herbicida amicarbazone utilizado na cultura da cana-de-açúcar, em solos contrastantes. Para tanto, utilizaramse amostras de Neossolo Quartzarênico (NR textura arenosa) e Latossolo Vermelho (LR textura argilosa). No potencial de lixiviação, após a aplicação do herbicida amicarbazone (NR 1,05 kg ha-1 e LR 1,40 kg ha-1), foram aplicadas lâminas de 0, 20, 40, 60, 80 e 100 mm de água nas colunas de solos. Avaliou-se o efeito residual, após a permanência do herbicida no solo de textura argilosa e arenosa, por períodos de 0, 25, 50, 75 e 100 dias após a aplicação (DAA) de amicarbazone (0; 1,05; 1,40 kg ha-1) nos tratamentos. O amicarbazone apresentou elevada lixiviação a partir da lâmina de 60 mm de água em solos de textura arenosa, constatando menor efeito residual. Em solo argiloso, lâminas de 20 a 80 mm de água reduziram a biomassa até a profundidade de 5-10 cm, com o uso deste herbicida. Com base nos resultados, conclui que o amicarbazone apresentou elevada lixiviação e menor efeito residual em solo arenoso. O efeito residual do amicarbazone foi prolongado conforme o aumento do teor de argila e
The infestation of weeds is a major biotic factor in the agroecosystem of cane sugar that may interfere in development and crop productivity. This study aimed to evaluate the potential for leaching and residual effects of the herbicide amicarbazone in contrasting soils. Samples were Quartzarenic Neosol (NR sandy texture) and Red Latosol (LR clay texture). For the leaching potential, after application of herbicide amicarbazone (NR 1.05 kg ha-1 and LR 1.40 kg ha-1), layers of 0, 20, 40, 60, 80 and 100 mm of water were applied to soil columns. We evaluated the residual effect after the permanence of the herbicide in soil of clay texture and sandy for periods of 0, 25, 50, 75 and 100 days after application (DAA) of amicarbazone (0, 1.05, 1.40 kg ha-1) treatments. The amicarbazone started showing high leaching from the 60 mm layer of water in sandy texture soils, evidencing a shorter residual effect. In clay soil, slides from 20 to 80 mm of water reduced the biomass until a depth of 5-10 cm, with the use of this herbicide. Based on these results, we conclude that the amicarbazone showed higher leaching and lower residual effects in sandy soil. The residual effect of amicarbazone was prolonged as the content of clay and organic matter present in the soil increased.
RESUMO
A infestação de plantas daninhas é um dos principais fatores bióticos presentes no agroecossistema da cana-de-açúcar que têm a capacidade de interferir no desenvolvimento e na produtividade da cultura. O trabalho teve como objetivo avaliar o potencial de lixiviação e efeito residual do herbicida amicarbazone utilizado na cultura da cana-de-açúcar, em solos contrastantes. Para tanto, utilizaramse amostras de Neossolo Quartzarênico (NR textura arenosa) e Latossolo Vermelho (LR textura argilosa). No potencial de lixiviação, após a aplicação do herbicida amicarbazone (NR 1,05 kg ha-1 e LR 1,40 kg ha-1), foram aplicadas lâminas de 0, 20, 40, 60, 80 e 100 mm de água nas colunas de solos. Avaliou-se o efeito residual, após a permanência do herbicida no solo de textura argilosa e arenosa, por períodos de 0, 25, 50, 75 e 100 dias após a aplicação (DAA) de amicarbazone (0; 1,05; 1,40 kg ha-1) nos tratamentos. O amicarbazone apresentou elevada lixiviação a partir da lâmina de 60 mm de água em solos de textura arenosa, constatando menor efeito residual. Em solo argiloso, lâminas de 20 a 80 mm de água reduziram a biomassa até a profundidade de 5-10 cm, com o uso deste herbicida. Com base nos resultados, conclui que o amicarbazone apresentou elevada lixiviação e menor efeito residual em solo arenoso. O efeito residual do amicarbazone foi prolongado conforme o aumento do teor de argila e
The infestation of weeds is a major biotic factor in the agroecosystem of cane sugar that may interfere in development and crop productivity. This study aimed to evaluate the potential for leaching and residual effects of the herbicide amicarbazone in contrasting soils. Samples were Quartzarenic Neosol (NR sandy texture) and Red Latosol (LR clay texture). For the leaching potential, after application of herbicide amicarbazone (NR 1.05 kg ha-1 and LR 1.40 kg ha-1), layers of 0, 20, 40, 60, 80 and 100 mm of water were applied to soil columns. We evaluated the residual effect after the permanence of the herbicide in soil of clay texture and sandy for periods of 0, 25, 50, 75 and 100 days after application (DAA) of amicarbazone (0, 1.05, 1.40 kg ha-1) treatments. The amicarbazone started showing high leaching from the 60 mm layer of water in sandy texture soils, evidencing a shorter residual effect. In clay soil, slides from 20 to 80 mm of water reduced the biomass until a depth of 5-10 cm, with the use of this herbicide. Based on these results, we conclude that the amicarbazone showed higher leaching and lower residual effects in sandy soil. The residual effect of amicarbazone was prolonged as the content of clay and organic matter present in the soil increased.