Fitorremediação de solo de várzea contaminado com os herbicidas do imazetapir e imazapique

Abstract

Adverse effects of the use of herbicides, such as toxicity to non-target species and production of persistent residues in soil and in surface water, have drawn attention and stimulated research to better understand the destination in the environment and to the development of efficient methods of decontamination. The Phytoremediation is a process based on the use of plants and their associated microbiota in order to extract, stabilize, metabolize, compartmentalize and / or degrade pollutants. In view of the exposured, this dissertation aimed to: 1) make a review on phytoremediation of soils contaminated with herbicides (Chapter I), 2) select plant species that show tolerance to the herbicide compound made by mixing Imazapic + imazethapyr (75 + 25 g e.a. L-1) to be tested for its phytoremediation efficiency (Chapter II), 3) evaluate the efficiency of plant species in the remediation of soil contaminated with the studied herbicide mixture, using the irrigated rice cultivar IRGA 417 as a bioindicator plant (Chapter III) and 4) evaluate the degradation of the herbicide compound formulated mixture of imazethapyr + Imazapic (75 + 25 g e.a. L- 1) in rhizosphere soil from the cultivation of Canavalia ensiformis, Glycine max, Lolium multiflorum, Lotus corniculatus, Stizolobium aterrimum and Vicia sativa (Chapter IV). The species espécies Avena strigosa, Lolium multiflorum, Secale cereale, Lotus corniculatus, Crotalaria juncea, Vicia sativa, Canavalia ensiformis, Stizolobium aterrimum, Glycine max and Raphanus sativus showed significant tolerance and phytoremediation potential, being efficient in descontaminating the soil with compost by the presence of the herbicide formulated mixture imazethapyr + Imazapic (75 + 25 g ai L-1). The highest metabolic activity, evidenced by the release of CO2 observed in soil vegetated with plant species Lutus corniculatus, Lolium multiflorum, Vicia sativa, Canavalia ensifromis, Stizolobium aterrimum and Glycine max, allows to infer that these species can influence the activity of the microbiota present in rhizosphere of the same, resulting in mineralization of the herbicides imazethapyr and Imazapic.