Avaliação econômica de diferentes processos para remoção de amônia de lixiviados de aterros sanitários

Este trabalho teve como objetivo realizar scale up e estudo de viabilidade econômica de duas formas de remoção de amônia em um lixiviado contendo teor de amônia em torno de 2000 mg/L. O estudo foi realizado a partir dos dados de tratabilidade obtidos em laboratório para remoção de amônia através de reação de precipitação de estruvita proposto por Schilling (2008) e através da remoção por arraste com ar proposta por Moura (2008) e considerou uma geração diária de 1000 m³, típica de grande parte dos aterros sanitários brasileiros de grande porte como o Aterro Metropolitano de Gramacho – RJ. Foram propostos fluxogramas industriais para ambos os processos. A partir dos fluxogramas obtidos pode-se estimar o valor do investimento necessário para a implementação de cada uma das propostas, e assim estimar o custo de tratamento destas duas rotas. Buscando a redução de custos e melhor desempenho dos processos foram propostas melhorias e sugestões de utilização de recursos existentes no próprio aterro, como o biogás, além do aproveitamento de resíduos gerados no tratamento, como o sulfato de amônio. Assim, a partir destes estudos, obteve-se um custo mensal de R$44, 94 por m3 de lixiviado tratado para o processo de precipitação de estruvita e um custo mensal de R$ 3,95 por m3 para o processo de arraste com ar, o que torna este processo mais atrativo que o anterior

O brincar na creche: os espaços escolares necessários

O presente estudo tem como principal objetivo analisar a importância do ato de brincar na creche do município de Itaocara. A fim de coletar informações com os profissionais da creche sobre a importância do ato de brincar e observar as brincadeiras planejadas para as crianças optei pelo tipo de pesquisa qualitativa utilizando na metodologia, técnicas de observação e aplicação de questionário. Os principais teóricos que utilizei no embasamento do trabalho são: Gilles Brougere, Kishimoto, Vygotski, Barros, além da legislação vigente sobre a educação infantil, e consulta a outros autores que foram destacados no decorrer do trabalho. A brincadeira é definida como uma atividade livre, que ajuda as crianças de várias formas, desenvolvendo, assim, sua capacidade de resolver problemas, demonstrar sua personalidade, gostos, trabalho em equipe, dentre tantos outros fatores que podem ser trabalhados no contexto de uma brincadeira. O fato de diversos profissionais da área da educação não darem a real importância em relação ao ato de brincar, justifica a relevância do presente estudo. Conclui-se que o jogo e a brincadeira são elementos essenciais ao desenvolvimento da criança, no aspecto cognitivo, afetivo e social. E que o espaço da sala de aula e o espaço externo devem ser adequados a mobilidade das crianças e ao desenvolvimento do trabalho pedagógicoThe present study it has as main objective to analyze the importance of the act to play in the day-care center of the city of Itaocara. In order to collect information with the professionals of the day-care center on the importance of the act to play and to observe the tricks planned for the children, it was used the qualitative research with the use of the comment techniques and application of questionnaire. The main theoreticians who used in the basement of the work are: Gilles Brougere, Kishimoto, Vygotski, Barros, beyond the current law on the infantile education and consult other authors who detached when elapsing of the work. The trick is defined as a free activity, that helps the children of some forms, developing, thus, its capacity to decide problems, to demonstrate its personality, gostos, work in team, amongst as much other factors that can be worked in the context of a trick. The fact of diverse professionals of the area of the education not to give the real importance in relation to the act to play, justifies the relevance of the present study. One concludes that the game and the trick are essential elements to the development of the child, in the cognitivo aspect, affective and social. E that the space of the classroom and the external space must be adjusted mobility of the children and to the development of the pedagogical wor

Heavy Metals in P Fertilizers Marketed in Brazil: Is This a Concern in Our Agroecosystems?

Abstract Fertilizers are key for sustainable use of land and for intensification of crop production, especially in tropical agroecosystems, which have soil fertility constraints that hamper agricultural production on weathered soils. Heavy metals (HM) occur in fertilizers in low concentrations, as contaminants. Yet, some HM are plant nutrients and are intentionally included in fertilizer formulations. Exposure to high levels of HM (nutrient or not) could pose a health risk to humans. This risk may be estimated by collecting data on HM content in soils and plants (e.g., edible parts) in the field, as well as thru modeling. This work presents information concerning HM contents - with a focus on cadmium - in Brazilian fertilizers and agroecosystems - including agricultural products -, aiming to contribute to a better definition of safe limits of HM in phosphate fertilizers, soils, and food. These limits are key not only for food safety purposes, but also for assuring fair trade. In addition, we demonstrate the usefulness of a tool - the software EtraceProDB -, for easy calculation of risk-based concentrations (RBC) of HM in inorganic fertilizers post application, which suggest safe limits for agricultural use. The purpose of this software is to calculate values of HM concentrations in inorganic fertilizers that may, flexibly, be used by regulators to protect human and soil health. The results obtained indicate that HM do not cause harm to human health when considering post application of phosphate fertilizers in Brazil. Also, a survey of HM contents in Brazilian food and food products evidenced the safety of agricultural crops with respect to their contents of As, Cd, and Pb. Our findings concerning RBC and analyses of HM in mixed fertilizers, as well as current information published in Brazil suggest that HM contents - Cd inclusive - in major agroecosystems as well as the HM limits currently established for P fertilizers by the Brazilian legislation are safe in terms of health risk assessment. Considering the great importance of Brazil as a global food provider, such results are relevant to show that fertilizer use in Brazilian agriculture is done in such a way as to guarantee the production of healthy crops as well as adequate food quality criteria

Selenium biofortification of soybean genotypes in a tropical soil via Se-enriched phosphate fertilizers.

Soybean is a major crop in Brazil and is usually grown in oxidic soils that need high rates of phosphate (P) fertilizers. Soybean is also very suitable for biofortification with Se, since its grains have high protein contents and are widely consumed worldwide (directly or indirectly). Few studies have addressed Se application under field conditions for soybean biofortification, especially in tropical soils. Here, we evaluated agronomic and physiological responses resulting from different strategies for biofortifying soybean grains with Se by applying this element via soil, using both conventional and enhanced-efficiency P fertilizers as Se carriers. The experiment was carried out at the Uva Farm, in Capão Bonito (São Paulo), Brazil. The experimental design was a randomized block split-plot design, with four fertilizer sources-conventional monoammonium phosphate (C-MAP), conventional monoammonium phosphate + Se (C-MAP + Se), enhanced-efficiency monoammonium phosphate (E-MAP), and enhanced-efficiency monoammonium phosphate + Se (E-MAP + Se), and four soybean genotypes (M5917, 58I60 LANÇA, TMG7061, and NA5909). The selenium rate applied via C-MAP + Se and E-MAP + Se was 80 g ha-1. The application of the tested fertilizers was carried out at the sowing of the 2018/2019 cropping season, with their residual effect being also assessed in the 2019/2020 cropping season. Selenium application increased grain yield for the TMG7061 genotype. For all evaluated genotypes, Se content in grains increased in the 2018/2019 harvest with the application of Se via C-MAP + Se and E-MAP + Se. In general, the application of Se via C-MAP favored an increase in amino acid contents in grains and decreased lipid peroxidation. In summary, the application of Se-enriched P fertilizers via soil increased soybean grain yield, leading to better grain quality. No residual effects for biofortifying soybean grains were detected in a subsequent soybean cropping season

Assessing arsenic, cadmium, and lead contents in major crops in Brazil for food safety purposes

AbstractThe food chain is one of the major sources of human exposure to non-essential trace elements (TEs) present in soils. Human exposure to contaminated food is a worldwide health concern and a food safety issue that threatens agricultural trade. To assess the quality of Brazilian food products with respect to non-essential TEs, we evaluated arsenic (As), cadmium (Cd), and lead (Pb) contents in five major crops grown in Brazil: rice, wheat, corn, soybeans, and potatoes. The samples were collected from field trials with a record of long-term use of phosphate fertilizers in the states of Mato Grosso and Minas Gerais, Brazil. The TE concentrations in soils were all bellow the maximum allowable concentrations for agricultural soils. The mean concentrations of As, Cd, and Pb (μgkg−1 dry weight) were as follows: below the detection limit <15, 29, and <40 for rice; 19, 23, and 64 for wheat; 47, 40, and 95 for corn; 65, 23, and 106 for soybeans; and 59, 22, and <40 for potatoes, respectively. Significant differences were found in the As and Cd contents of the different wheat cultivars. The levels of As, Cd, and Pb found in the studied crops are well below the values reported in the literature and are in accordance with the Codex Alimentarius and the European Union and Brazilian guidelines, indicating that the concentrations of these elements in the crops do not pose a risk to human health

Effects of lime and organic amendments derived from varied source materials on cadmium uptake by potato

Repeated applications of Cd-rich phosphate fertilizers have resulted in elevated concentrations of this toxic element in some New Zealand soils. Exceedance of the food safety standard for Cd (0.1 mg kg⁻¹ fresh weight) has been reported for potato (Solanum tuberosum L.). Composts may efficiently sorb Cd in soil and therefore reduce its phytoavailability, leading to reduced uptake by plants. We aimed to determine the potential of various composts, shredded corn stover, and lime at two different rates to reduce the transfer of Cd from a soil (containing 1.45 mg kg⁻¹ Cd) to potato (var. 'Nadine'). In the control, the peeled tubers, skins, leaves, and stems had Cd concentrations of 0.04, 0.09, 0.26, and 0.53 mg kg⁻¹ dry weight, respectively. There was a 71% reduction in tuber Cd concentrations in potatoes grown in soil amended with 5% (w/w) shredded corn stover, although it significantly decreased potato biomass. Potatoes grown in soil amended with pig manure compost, mushroom compost, sawdust-animal waste compost, and municipal compost at rates of either 2.5 or 5% (w/w) reduced tuber Cd concentrations by 58 to 66%, 46 to 63%, 52 to 53%, and 29 to 49%, respectively. Lime (1.3%) application in soil reduced tuber Cd concentrations by 50%. Composts significantly increased tuber biomass. Further work is warranted to identify the key components of composts that result in reduced Cd uptake by plants

Simultaneous biofortification of rice with zinc, iodine, iron and selenium through foliar treatment of a micronutrient cocktail in five countries

Widespread malnutrition of zinc (Zn), iodine (I), iron (Fe) and selenium (Se), known as hidden hunger, represents a predominant cause of several health complications in human populations where rice (Oryza sativa L.) is the major staple food. Therefore, increasing concentrations of these micronutrients in rice grain represents a sustainable solution to hidden hunger. This study aimed at enhancing concentration of Zn, I, Fe and Se in rice grains by agronomic biofortification. We evaluated effects of foliar application of Zn, I, Fe and Se on grain yield and grain concentration of these micronutrients in rice grown at 21 field sites during 2015 to 2017 in Brazil, China, India, Pakistan and Thailand. Experimental treatments were: (i) local control (LC); (ii) foliar Zn; (iii) foliar I; and (iv) foliar micronutrient cocktail (i.e., Zn + I + Fe + Se). Foliar-applied Zn, I, Fe or Se did not affect rice grain yield. However, brown rice Zn increased with foliar Zn and micronutrient cocktail treatments at all except three field sites. On average, brown rice Zn increased from 21.4 mg kg–1 to 28.1 mg kg–1 with the application of Zn alone and to 26.8 mg kg–1 with the micronutrient cocktail solution. Brown rice I showed particular enhancements and increased from 11 μg kg–1 to 204 μg kg–1 with the application of I alone and to 181 μg kg–1 with the cocktail. Grain Se also responded very positively to foliar spray of micronutrients and increased from 95 to 380 μg kg–1. By contrast, grain Fe was increased by the same cocktail spray at only two sites. There was no relationship between soil extractable concentrations of these micronutrients with their grain concentrations. The results demonstrate that irrespective of the rice cultivars used and the diverse soil conditions existing in five major rice-producing countries, the foliar application of the micronutrient cocktail solution was highly effective in increasing grain Zn, I and Se. Adoption of this agronomic practice in the target countries would contribute significantly to the daily micronutrient intake and alleviation of micronutrient malnutrition in human populations