Water contamination by heavy metals is a growing concern among public officials and citizens due to their high potential toxicity to living things and the environment. Macrophytes have been studieds for use in a cleaning up polluted water bodies, due to their favorable characteristics. The various species can respond differently to environments contaminated with heavy metals. They can be sensitive, showing symptoms of toxicity and intolerant of high contamination levels, or tolerant, using extra or intracellular mechanisms to allow them to grow in the presence of these contaminants. In this review, we present the main mechanisms used by plants in response to contamination by heavy metals.
Concentração de metais pesados em espécies arbóreas utilizadas para revegetação de área contaminada 1Heavy metals concentration in tree species used for revegetation of contaminated area ), evidenciando contaminação com esse elemento. Os maiores teores dos metais pesados foram encontrados na fração residual (F5), indicando baixa disponibilidade destes elementos no substrato. Com relação ao Cd, elevadas concentrações também foram encontradas na fração trocável F2, considerada uma fração em que os contaminantes se apresentam com certa mobilidade e biodisponibilidade. As espécies vegetais estudadas apresentaram desenvolvimento dentro dos padrões normais, mostrando tolerância a áreas contaminadas com Cd, que tendeu a se acumular nas raízes das plantas, com exceção da Córdia -africana. Palavras-chave:Arborização. Revegetação. Solos-descontaminação.ABSTRACT -This study aims to evaluate the potential of tree species Cordia africana Lam., Mimosa caesalpineafolia Benth., Acacia angustissima (Mill.) Ktze. and Anadenanthera colubrina (Vell.) Brenan in the phytostabilization of heavy metal from a substrate contaminated. Four specimens of each tree specie were randomly determined for evaluations. Substrate samples were collected in the projection of the canopy trees of each specimen at depths 0-10, 10-30 and 30-50 cm for determining pseudototal concentration and chemical fractionation of heavy metals.Were collected data on roots depth, diameter at breast height, canopy diameter and plant height for each specimen. Samples of root, stem, bark and leaf were collected for analysis of heavy metals zinc (Zn), manganese (Mn), cadmium (Cd), lead (Pb) and copper (Cu). The Cd concentration in the substrate was above the investigation value defined by CONAMA (3,0 mg kg -1 ), showing contamination with this element. However, the highest concentrations of other studied heavy metals were found in the residual fraction (F5), indicating low availability of these elements in the substrate. High concentrations of Cd were also found in the exchangeable fraction F2, which is considered a fraction in which contaminants are present with some mobility and bioavailability. The plants showed development within the normal patterns, showing tolerance to Cd-contaminated areas, which tended to accumulate in the roots, except in the Córdia -africana.
A disciplina de Química muitas vezes é vista como algo amedrontador e impossível de criar empatia para os estudantes em geral dado o seu conteúdo um tanto quanto complexo. Haja vista este problema há uma busca pela desmistificação da referida disciplina em relação aos estudantes e até mesmo alguns docentes, utilizando para isso artefatos como atividades lúdicas e aulas práticas e experimentais. O objetivo deste estudo foi a realização de quatro aulas práticas, ministradas por discentes do 5º período do curso de Licenciatura em Química, dentro da disciplina de Práticas Pedagógicas I, no Instituto Federal de Educação, Ciência e Tecnologia do Sul de Minas (IFSULDEMINAS) - Campus Pouso Alegre, para comprovar que o ensino da química pode ser realizado com algumas práticas sem a necessidade de um laboratório propriamente dito. Houve a possibilidade de auxílio imediatamente de acordo com as dificuldades encontradas pelos estudantes ao longo das aulas, que possuem potencial para serem aplicadas novamente tanto na disciplina de Práticas Pedagógicas I destinada ao 5º período do curso de Licenciatura em Química quanto para demais turmas de Cursos Superiores ligadas à Química, além de Ensino Fundamental e Médio. A ausência de um laboratório não impede à realização das práticas descritas e realizadas aqui.
Global attempts to renew scientific education aim to stop the decline of young people's interest in science and technology, and to promote the development of citizens' scientific literacy for sustainable development. Among other changes, these aims require the adaptation of K12 Biological Science Teacher’s training to meet the new objectives.Scientific literacy involves knowing science and how knowledge is developed and validated, recognizing the interactions between science, technology and society, that is, the nature of science (NoS; a set of meta-scientific contents that encompass historical, epistemological and sociological aspects of science with great value for scientific education). It also involves grasping of cognitive skills underlying critical thinking (CT; a set of cognitive abilities, including self-regulation and metacognitive processes) and creative problem solving. Therefore, scientific literacy contributes to making informed decisions, facilitating the participation of citizens in situations and dilemmas of scientific tenor.In addition, CT is closely related to the performance of educators in their professional work. Particularly, in the teaching of science, CT skills favour and enhance the learning of concepts and theories linked not only to science but also to the NoS.Considering the current conditions of middle-higher K12 Biological Science Teachers’ formation and classrooms´ limitations in our country and the region, we propose a pilot project aiming to promote the transformation of initial teachers´ training, seeking to improve the development of CT skills and to deepen NoS comprehension. It will involve the immersion of K12 Biological Science Teacher students in Biological Science Living Physical and "mirror" Virtual Reality Laboratories. These laboratories will be equipped with "do it yourself" (DIY), "do it with others" (DIWO) and "bring your own device" (BYOD) technologies for the implementation of research-type activities framed in the philosophy of the "fabrication laboratories". The virtual platform will also comprise a library with didactic resources under permissive licenses to ensure a broader impact.Within these environments, K12 Biological Science Teacher students will engage in the creation of didactic units involving problem solving and knowledge building in parallel to deeper understanding of scientific processes. We also hope to promote the creativity and innovation of the participants, and the appropriation of DIY/DIWO/BYOD and virtual reality technologies as educational resources in the classroom and everyday life.Thanks to the virtual environment, this approach would also allow to reach both National and International K12 Biological Science Teacher students and graduate Biological Science Teachers. Considering the universal access to the Internet and free access to educational platforms in several countries, we also hope to impact on the non-formal and informal Biological Science education and contribute to achieving quality education for all (Objective # 4 of the Agenda for Sustainable Development 2030, UNESCO) beyond geographical and cultural barriers.This pilot project will be implemented by an interinstitutional, multidisciplinary and international team. It will capitalize on confluent groups´ previous experience and complementary strengths in Science didactics (particularly biology), engineering, arts, virtual reality, fabrication, as well as open hardware and open software culture.The experimental approach corresponds to a quasi-experimental pre-test/post-test design with control groups, and formative and summative evaluation.As a result of the implementation of this educational innovation we expect to contribute to the improvement of Biological Science Teachers students´ CT skills and promote their active involvement in practical activities that should enhance their professional activity.
Atualmente a contaminação do solo se dá principalmente pela deposição inadequada de resíduos contaminados, causando danos a longo prazo e representando um risco eminente para o meio ambiente e também para o ser humano. Este trabalho propôs a investigação ambiental do solo na condomínio residencial do bairro Volta Grande IV, situado na cidade de Volta Redonda- RJ. Tal área foi utilizada como depósito de resíduos de siderurgia, classificados como resíduos perigosos segunda a NBR 10004 da ABNT. Após o encerramento do depósito, foi construído no local um conjunto habitacional que atualmente serve como residência para aproximadamente 200 famílias. Desta forma, o objetivo do trabalho foi realizar um estudo de caso do histórico de contaminação no bairro Volta Grande IV, além de diagnosticar a existência de metais pesados em solos presentes em áreas públicas ainda não impermeabilizadas. A determinação dos metais presentes em tais áreas seguiu a metodologia de digestão por água régia, especificada na ISO 11466/1995. Os metais selecionados para análise neste trabalho foram: chumbo (Pb), níquel (Ni), zinco (Zn) e cobre (Cu), estando estes, com exceção do Pb, acima dos valores de referência estabelecidos pela CETESB. Também foi determinado o pH das amostras de solo, os quais se apresentaram alcalinos em todos os pontos de coleta.
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