Atividade biorremediadora de Chromobacterium violaceum a metais pesados em ambientes aquáticos no semiárido brasileiro: ações para vigilância ambiental e educação em saúde

Abstract

The low water quality in the Brazilian Semiarid, in the most of cases is associated to human activities, such as the release of metallic waste from the mined industry. This study aims to compare and discuss the research evolution performed worldwide, which made use of the potential of C. violaceum for bioremediation of heavy metals; understand the bioremediation and phenotypic resistance patterns in wild and Standard strains (ATCC 12472) of heavy metals, iron (Fe), zinc (Zn) and manganese (Mn), in differents responce time, concentrations and metal interactions; evaluate the physicochemical and microbiological parameters in Engenheiro Armando Ribeiro Gonçalves reservoir, located in the county of Jucurutu (semiarid region of Rio Grande do Norte - RN); analyze the approach of the subject bioremediation in textbooks from elementary and high school appointed by 2014 and 2012 PNLD, respectively, as well as developing an educational product targeted to approaching the technical and scientific knowledge and the environment interface. The systematic review was limited to research published between 2001 to 2015, using LILACS, PubMed, and SciELO databases. The evaluation of C. violaceum resistance for heavy metals occurred in decreasing concentrations of Fe, Zn and Mn, at intervals of 24, 48 and 72 hours by a full factorial design 23; the isolation and microbiological identification were performed according to the methodology recommended by the Standard Methods for Examinations of Water and Wastewater; the evaluation the use of the potential of C. violaceum for bioremediation of heavy metals was performed by atomic absorption spectrophotometry (AAS), while the analysis of the reporting units was carried out from the adaptation of Bardin content analysis methodology (2004). The systematic survey showed that bioleaching technique was further discussed; gold was the bioremediated substrate most mentioned, and cyanidation was the prevalent phenotypic mechanism. Genetic mechanisms were mentioned in 29.4% of the publications, and among proteins transcribed by C. violaceum 18.3% were hypothetical. Whereas experimental data indicated that both strains of C. violaceum showed resistance to the metals tests on different scales concentrations, interactions and exposure intervals (p<10-5). However that wild showed a more efficient acute phase response compared to the standard, especially for metal concentrations from 80 to 480 g/100 mL x 10-3. The physicochemical water analysis revealed acceptable parameters as the current resolution, except for point five, as regards the analysis of pH, on this point was the isolation of C. violaceum, whose the use in bioremediation of Fe, Zn and Mn showed more efficient as the ATCC strain (p<10-5). Finally, the educational axis directed to the analysis of the textbooks showed that all of them, although they were recommended by PNLD, showed shortcomings regarding the subject bioremediation, making it necessary to develop educational materials aiming at to supply such an approach. The evaluated data demonstrated the fundamental importance of C. violaceum in bioremediation of heavy metals and highlights the importance of environmental monitoring, development and application of bioremediation in impacted environments and emphasizes the need to reworking the environmental education and biotechnology interface, in order to enable the teacher and high school and fundamental students to a critical reflection about the relationships involving environmental pollution and possible mitigation tools of this problem.