Caracterización de consorcios microbianos lixiviantes de sulfuro de cobre aislados de drenajes ácidos de minas altoandinas

La biolixiviación, usando consorcios microbianos, es considera una alternativa ecoeficiente y de bajo costo para la recuperación de metales a partir de minerales de baja ley. En este estudio, se realizó la caracterización fisiológica y molecular de consorcios microbianos psicrotolerantes lixiviantes (CMPL), aislados de drenajes ácidos de minas de cuatro localidades mineras de las provincias de Pasco y Huarochirí, Perú, ubicados sobre los 4200 m de altitud. Se aislaron seis consorcios adaptados a medio 9K con ion ferroso y medio basal 9K con CuS al 0.5% p/v a 15 °C. Se evidenció la liberación de cobre en todos los consorcios. El CMPL con mejor crecimiento, presentó una recuperación de cobre de 12.47% en 30 días de evaluación. Los análisis de la secuenciación del gen ARNr 16S de la comunidad bacteriana, mostraron que los CMPL están dominados por el género Acidithiobacillus, seguido de Acidiphilium. En conclusión, se obtuvieron consorcios que pueden ser aplicados en biolixiviación de cobre en la minería altoandina.

Bioleaching, using microbial consortia, is regarded as an eco-efficient and cost-effective alternative for the recovery of metals from low-grade ores. In this study, we conducted physiological and molecular characterization of psychrotolerant leaching microbial consortia (PLMC) isolated from acid mine drainage in four mining sites within the Pasco and Huarochirí provinces of Peru, situated at altitudes above 4200 meters. Six consortia adapted to a medium containing ferrous ions (9K medium) and a basal medium with 0.5% w/v CuS at 15°C were isolated. All consortia exhibited copper release. The PLMC with the most robust growth achieved a copper recovery of 12.47% within 30 days of evaluation. 16S rRNA gene sequencing analysis of the bacterial community revealed that the PLMCs were predominantly dominated by the genus Acidithiobacillus, followed by Acidiphilium. In conclusion, consortia suitable for copper biolixiviation in high-altitude mining contexts were successfully obtained.

Microorganisms used for bioleaching of metals from typical solid wastes and their leaching mechanism: a review / 生物工程学报

Typical solid wastes contain many metal resources, which are worthy of recycling. The bioleaching of typical solid waste is affected by multiple factors. Green and efficient recovery of metals based on the characterization of leaching microorganisms and the elucidation of leaching mechanisms may contribute to the implementation of China's "dual carbon" strategic goals. This paper reviews various types of microorganisms used for leaching metals from typical solid wastes, analyzes the action mechanism of metallurgical microorganisms, and prospects the application of metallurgical microorganisms to facilitate the application of metallurgical microorganisms in typical solid wastes.

Mobilidade de contaminantes em solos arenosos após a aplicação de águas residuárias tratadas produzidas em indústria siderúrgica / Contaminant mobility in sandy soils after application of treated wastewater produced in the steel industry

RESUMO Este trabalho teve como objetivo realizar um estudo de modelagem da dispersão de contaminantes no solo com águas residuárias produzidas e tratadas em uma indústria siderúrgica. Para isso, foram realizados ensaios de coluna de lixiviação utilizando amostras de solo coletadas nas áreas dentro da indústria onde aconteceria o reúso das águas residuárias tratadas nas estações de tratamento da própria siderúrgica. Com base nos ensaios, foram geradas curvas de eluição (breakthrough curves), para análise da mobilidade dos contaminantes no solo, e obtidos os parâmetros de transporte (coeficiente de dispersão, retardamento e dispersividade). As águas residuárias produzidas na siderúrgica apresentam baixas concentrações de metais pesados após o tratamento realizado, sendo apenas o ferro e o zinco, contaminantes de maior preocupação para a disposição no solo. Os solos analisados, com elevado percentual de areia, demonstraram ineficiência na retenção dos contaminantes presentes, aumentando os riscos de contaminação da água subterrânea. Conclui-se que, para a indústria siderúrgica realizar o reúso não potável das águas residuárias, deve-se associar este a técnicas de manejo e conservação do solo que aumentem a capacidade do solo em adsorver contaminantes, ou de impermeabilização na área de resfriamento de placas.

ABSTRACT This research aimed to carry out a modeling study on the dispersion of contaminants in the soil with wastewater produced and treated in a steel industry. For this purpose, column leaching tests were performed using soil samples collected in areas inside the industry where the reuse of treated wastewater would occur. Based on the tests, elution curves (breakthrough curves) were generated to analyze the mobility of contaminants in the soil, and transport parameters were obtained (dispersion coefficient, delay, and dispersivity). The wastewater produced in the steelworks has low concentrations of heavy metals after the wastewater treatment is carried out, with only iron and zinc posing a risk for wastewater disposal. The analyzed soils, with a high percentage of sand, showed a low retention capacity for the contaminants present, increasing the risks of groundwater contamination. Therefore, the non-potable reuse of treated wastewater is possible in the steel industry, but it must be associated with soil management and conservation techniques that increase the capacity of the soil to adsorb its contaminants or the impermeabilization in the area of plate cooling.

Mobility and distribution of whey solutions in soil columns / Mobilidade e distribição de solutos de soro de leite em colunas de solo

In Brazil's food industry, dairy production is one of the most important sectors, whose most relevant byproduct is whey. Due to the difficulties of reuse and environmental impacts caused when discarded as effluent in water bodies, an alternative for its final destination would be the application of this residue in the soil. The purpose of this study was to determine chemical changes and mobility and distribution of solutes in the soil after applications of whey rates, as well as to analyze the leachate collected after each application. The test was carried out in a laboratory, in PVC columns filled with soil. The treatments consisted of 2 x 2 samples of a typical dystrophic Red-Yellow Oxisol (Oxisol) and a typical dystrophic fluvic Inceptisol (Inceptisol), sampled in the layers 0- 20 and 20-40 cm. Each experimental unit consisted of 11 PVC rings (diameter of 6.6 cm, height of 7 cm). The columns were arranged in a randomized complete block design with five replications. Four whey rates were applied, corresponding to a soil pore volume of 0.2, at intervals of six days. The leachate was collected 24 and 120 hours after each application to measure pH, electrical conductivity (EC), chemical oxygen demand (COD), contents of total N, N-NH4+, N-NO3-, Na, K, Ca, and Mg. Six days after the last whey application, the columns were opened and the soil of each ring was analyzed for pH, EC, total N, N-NH4+, N-NO3-, Na, K, Ca, and Mg. The high electrolyte concentrations of whey resulted in a general increase in soil EC. The increase of N-NH4+ and N-NO3- in the soil was high due to mineralization. High concentrations of K, Na and Ca caused displacement of Mg from the exchange complex. It was concluded that from an environmental standpoint, whey soil application is a viable alternative, given that problems of salinization and leaching of undesirable elements are avoided by an adequate management.

Entre os setores da indústria alimentícia, o segmento de laticínios é um dos mais importantes do Brasil, sendo o soro de leite o seu maior subproduto. Devido às dificuldades de reaproveitamento e aos impactos ambientais causados, quando descartado como efluente em corpos de água, uma alternativa para a sua destinação final seria a aplicação desse resíduo no solo. Objetivou-se com este trabalho determinar alterações químicas e a mobilidade e distribuição de solutos no solo após aplicação fracionada de soro de leite, assim como a caracterização dos percolados recolhidos após cada aplicação. O ensaio, em laboratório, foi conduzido em colunas de PVC preenchidas com solo. Os tratamentos corresponderam a um fatorial 2 x 2, sendo amostras de um Latossolo Vermelho-Amarelo distrófico típico (LVAd) e de um Cambissolo Flúvico Tb distrófico (CYbd), coletados em duas profundidades: 0­20 e 20­40 cm. Cada unidade experimental foi constituída de 11 anéis de PVC, com 6,6 cm de diâmetro interno e 7 cm de altura. As colunas foram dispostas em um delineamento experimental em blocos casualizados, com cinco repetições. Foram realizadas quatro aplicações de soro de leite, correspondentes a 0,2 volume de poros de solo, a cada intervalo de seis dias. O percolado foi recolhido após 24 e 120 horas de cada aplicação sendo realizadas as seguintes determinações: pH, condutividade elétrica (CE), demanda química de oxigênio (DQO), teores de N total, N-NH4+, N-NO3-, Na, K, Ca e Mg. Após seis dias da última aplicação de soro de leite, as colunas foram desmontadas e o solo de cada anel analisado. As análises compreenderam: pH em água, CE (1:5), N total, N-NH4+, N-NO3-, Na, K, Ca e Mg. As elevadas concentrações eletrolíticas do soro de leite provocaram aumento generalizado da CE no solo. Houve incremento maior do nitrogênio assimilável (N-NH4+ e N-NO3-) no solo em decorrência de processos de mineralização. Elevadas concentrações de K, Na e Ca causaram deslocamento de Mg do complexo de troca. Conclui-se que a aplicação de soro de leite no solo é uma alternativa viável do ponto de vista ambiental, desde que seja feito um correto manejo, a fim de evitar problemas de salinização e perdas por lixiviação de elementos indesejáveis.

Caracterización molecular de bacterias cultivables y no cultivables procedentes de pozas de lixiviación con cianuro / Molecular characterization of culturable and non-culturable bacteria from leaching pools with cyanide

En el presente estudio, las comunidades bacterianas en muestras de suelo y agua, procedentes de pozas artesanales de lixiviación con cianuro, fueron caracterizadas por análisis dependientes e independientes de cultivo. Para la caracterización de la comunidad bacteriana cultivable, se emplearon técnicas clásicas de microbiología hasta la obtención de cepas puras, las cuales fueron identificadas a nivel molecular. Por otro lado, las comunidades bacterianas no cultivables fueron caracterizadas por secuenciación de próxima generación del gen ARNr 16S. La comunidad bacteriana cultivable estaba principalmente representada por los géneros Pseudomonas, Bacillus y Acinetobacter; mientras que las comunidades no cultivables, predominantes en muestras de suelo, fueron los filos Proteobacteria (12.91%), Firmicutes (11.32%), Actinobacteria (11.25%) y Bacteroidetes (10.16%). Por otro lado, en muestras de agua predominaron los filos Firmicutes (59.16%) y Actinobacteria (38.99%).

In the present study, bacterial communities in soil and water samples, from artisanal leaching pools with cyanide, were characterized by dependent and independent culture analyzes. For the characterization of the culturable bacterial community, classical techniques of microbiology were used, until obtaining pure strains, which were identified at the molecular level. On the other hand, uncultured bacterial communities were characterized by next-generation sequencing of the 16S rRNA gene. The culturable bacterial community was mainly represented by the genera Pseudomonas, Bacillus and Acinetobacter; while the predominant uncultured communities, in soil samples, were the proteobacteria (12.91%), Firmicutes (11.32%), Actinobacteria (11.25%) and Bacteroidetes (10.16%). On the other hand, in water samples, the edges of Firmicutes (59.16%) and Actinobacteria (38.99%) predominated.

Foliar application of plant growth regulators changes the physiological quality of crambe seeds

The application of plant growth regulators can manipulate the development of cultivated plants, and their physiological effects may be reflected in the physiological quality of the seeds. This study evaluated the effects of plant growth regulators (PGR) on the physiological quality of crambe seeds produced in the 2014 and 2015 harvests. During crop development, we applied two foliar sprayings of the following treatments: 1) control treatment with distilled water; 2) indole-3-acetic acid 100 mg L-1 (IAA); 3) 3-gibberellic acid P.A. 100 mg L-1 (GA3); 4) commercial PGR Stimulate® 6 mL L-1. The seeds were harvested and evaluated for water content, germination percentage and germination speed index (GSI), electrical conductivity and concentrations of leached Ca, Mg and K ions. Means were compared by Tukey ́s and Dunnett tests (p<0.05). Applying Stimulate® increased the germination percentage and the germination speed index, while IAA application showed an opposite effect, increasing the electrical conductivity of crambe seeds. Calcium leaching decreased with IAA application, and all regulators reduced K leaching. We therefore infer that the application of plant growth regulators influences the physiological quality of crambe seeds.

Stability and phosphorus leaching of tilapia feed in water / Estabilidade e lixiviação do fósforo da ração de tilápia na água

ABSTRACT: The present research aimed to investigate the stabil¬¬ity of pellets and phosphorus leaching of diets formulated for juveniles of Nile tilapia (Oreochromis niloticus), with different sources of phosphorus and different exposure times in water. Six diets were elaborated by varying the source of phosphorus (1 ‒ dicalcium phosphate (DP); 2 ‒ meat and bone meal (MBM); 3 ‒ poultry meal (PM); 4 ‒ anchovy meal (AM); 5 ‒ tilapia filleting industrial meal (TM); 6 ‒ calcined bone meal (CBM)) and, then, were submitted to four exposure times in water (5, 10, 15 and 20 minutes), with three replicates. Thus, 72 aquariums of 30‒liters were used, each being an experimental unit. All diets were evaluated for electrical conductivity of water, turgidity of pellets, mineral matter leaching, flotation of pellets, and total phosphorus leaching. Only turgidity and flotation of pellets varied with the different sources of phosphorus in the diets. The MBM diet had the highest turgidity of pellets. The PM, AM, and CBM diets had the highest flotation of pellets. The total phosphorus leaching had a linear effect with the increase of the exposure time, showing a greater release of phosphorus in the water with increase of exposure time. Data showed that PM, AM, and CBM diets had less potential impact on the aquatic environment. Conversely, the TM diet has greater polluting potential. These results showed that diets formulated with different sources of phosphorus exhibit distinct actions in the water, providing different effects on the fish culture environment.

RESUMO: O presente trabalho tem como objetivo investigar a estabilidade de pellets e a lixiviação do fósforo na água proveniente de diferentes dietas formuladas para juvenis de tilápia do Nilo (Oreochromis niloticus), considerando distintas fontes de fósforo e diferentes tempos de exposição na água. Para tanto, foram elaboradas seis dietas com variação da fonte de fósforo (1: fosfato dicálcico (DP); 2: farelo de carne e ossos (MBM); 3: farelo de aves (PM); 4: farelo de anchova (AM); 5: farelo industrial de filetagem de tilápia (TM); 6: farelo de osso calcinado (CBM)), as quais foram submetidas a quatro tempos de exposição em água (5, 10, 15 e 20 minutos), com três repetições. Utilizaram-se 72 aquários de 30 litros, sendo cada um deles uma unidade experimental. A água dentro dos aquários foi mantida sob constante aeração e temperatura ao redor de 25 °C. Todas as dietas foram avaliadas quanto à condutividade elétrica da água, turgidez, lixiviação de matéria mineral, flotação de pellets e lixiviação total do fósforo. Apenas a turgidez e a flutuação dos pellets variaram com as diferentes fontes de fósforo nas dietas. A dieta MBM apresentou a maior turgidez de pellets. As dietas PM, AM e CBM apresentaram a maior flutuação de pellets. A lixiviação do fósforo total teve um efeito linear com o aumento do tempo de exposição, resultando em maior liberação de fósforo na água. A lixiviação de matéria mineral apresentou interação entre fontes de fósforo e tempos de exposição das dietas, com efeito linear para a dieta TM. As dietas PM, AM e CBM apresentam as menores concentrações de efluentes em relação a dieta TM. Esses resultados revelaram que dietas formuladas com diferentes fontes de fósforo apresentam ações distintas na água em relação ao potencial poluidor.

Degradación de hojarasca y aporte de nutrientes del manglar en la Laguna Mecoacán, Golfo de México / Leaf litter degradation and nutrient supply in the mangroves of Mecoacán Lagoon, Gulf of Mexico

Resumen Los manglares son ecosistemas de importante productividad primaria, donde se establece un flujo de energía (nutrientes) con zonas adyacentes y su ambiente acuático, impulsado principalmente por los procesos de degradación. El objetivo del estudio fue estimar el coeficiente de degradación diario (k) de hoja de mangle por medio de bolsas de degradación, en relación con los factores físico químicos del suelo y el aporte de nutrientes (fósforo y nitrógeno) en sedimento del manglar de la Laguna Mecoacán, Golfo de México. El coeficiente de degradación se estimó por medio de bolsas de degradación de hojarasca en seis sitios de monitoreo mensual. Se identificó una rápida degradación durante el primer mes de hasta 51 % en Avicennia germinans (L.) Stearn asociado a procesos de lixiviación por condiciones de inundación. La degradación (k) de Rhizophora mangle L. (k= 0.0052 ± 0.0002) (F= 12.2 p<0.05 n= 216) y Laguncularia racemosa (L.) Gaertn (k= 0.005 ± 0.0003) (F= 3.7 p= 0.02 n= 108) difieren significativamente de A. germinans (k= 0.009 ± 0.0003) (F= 1.2 p= 0.02 n= 216). En relación al T50 de R. mangle y L. racemosa presentaron mayor tiempo de degradación (133 y 138 días respectivamente) comparado con A. germinans (74 días). Se registró una correlación significativa entre la materia orgánica y la humedad del suelo con la constante de descomposición de A. germinans (r= 0.65 p< 0.05 y r= 0.55 p< 0.05 respectivamente). El más alto contenido de nitrógeno total se dio en Pajaral (2 683 mg.Kg) y presentó alta correlación con el contenido de materia orgánica (r= 0.9 p= 0.03); en relación al fósforo total, el nivel más alto se presentó en Boca (2 031 mg.Kg) correlacionado de forma negativa con el pH (r= -0.61 p< 0.05). En conclusión, las diferencias en la velocidad de degradación de las hojas de mangle dependen de la especie (composición foliar), tiempo de exposición o inmersión en agua (patrón de inundación) y heterogeneidad del sedimento (i.e., textura, pH, contenido de humedad y densidad aparente).

Abstract Mangroves are ecosystems with a high primary productivity that is mainly driven mainly by degradation processes. Energy (nutrients) flows from mangroves toward adjacent zones and the surrounding aquatic environment. The objective of the present study was to estimate the daily degradation coefficient (k) of mangrove leaves in relation to physical-chemical soil factors and in situ nutrient supply (phosphorus and nitrogen) in Mecoacán Lagoon, Gulf of Mexico. Leaf litter degradation bags were placed at six monthly monitoring sites to evaluate degradation and to calculate the corresponding degradation coefficients. A rapid degradation of up to 51 % was observed for Avicennia germinans (L.) Stearn during the first month in association with leaching resulting from flood conditions. The degradation of Rhizophora mangle (L.) (k= 0.0052±0.0002) (F= 12.2 p< 0.05 n= 216) and Laguncularia racemosa (L.) Gaertn (k= 0.005±0.0003) (F= 3.7 p= 0.2 n= 108), differed significantly from that of A. germinans (k= 0.009 ± 0.0003) (F= 1.2 p= 0.2 n= 216) did not present significant differences. To reach T50 degradation, R. mangle and L. racemosa required more time (133 and 138 days, respectively) than A. germinans (74 days). Organic matter and soil humidity were significantly correlated with the decay constant of A. germinans (r= 0.65 p< 0.05 and r= 0.55 p< 0.05, respectively). Total nitrogen content was highest in the Pajaral site (2 683 mg.kg) and was also highly correlated with organic matter content (r= 0.9 p= 0.003). Total phosphorus content was highest in the Boca site (2 031 mg.kg) and was also negatively correlated with pH (r= -0.61 p= 0.004). In conclusion, differences in the rate of mangrove leaf degradation depend on the involved species (leaf composition), time of exposure or immersion in water (flooding patterns) and sediment heterogeneity (i.e., texture, pH, humidity content and bulk density). Rev. Biol. Trop. 66(2): 892-907. Epub 2018 June 01.

The effect of Hydropolymers on soil microbial activities in Mediterranean areas / El efecto de los polímeros absorbentes en la actividad microbiológica del suelo bajo condiciones mediterráneas

ABSTRACT Objectives. The aim of this study was to evaluate the effect of the hydropolymer TerraCottem on soil microbial activity by measuring soil respiration and leaching of mineral nitrogen. Materials and methods. The incubation experiment contained control variants with natural soil of Nerja area (South Spain, inside the Sierra Tejeda, Almijara and Alhama Natural Park, 36.7985173° N 3.8511693° W; WCGS84), variants with the addition of easy available nitrogen compounds (kg N ha-1), easy accessible carbon compounds (1% glucose solution) and a combinations of both. Within each variant, the recommended amount of control hydropolymers (1.5 kg/m3) and a double dose of 3.0 kg/m3 were compared. Results. Showed that respiration activity of the soil in this Mediterranean area was not eliminated by the lack of ready available nitrogen or carbon substrates. Furthermore, differences in CO2 production between the variants containing different amounts of hydropolymers were not significant. A statistically significant difference in the CO2 production was found in the first week compared to longer time periods. Conclusions. The mineral nitrogen leaching measurement showed that the biological activity of the studied is not affected by nitrogen dynamics which is balanced regardless of the amount of applied hydropolymer. On the other hand, leaching processes occurred when soil was doped only with nitrogen compounds or only carbonaceous, a problem that can appear after fertilizers application.

RESUMEN Objetivo. El objetivo de este estudio pasa por evaluar el efecto del-Terracottem- en la actividad microbiana del suelo mediante la medida de la respiración edáfica y la pérdida de nitrógeno mineral por lixiviación. El ensayo se ha realizado en condiciones de laboratorio controladas y con suelos naturales. Materiales y métodos. Para el experimento, se han diseñado varios tratamientos: i) suelos naturales a los que se les ha adicionado compuestos nitrogenados de libre disponibilidad (Kg N ha-1); ii) suelos naturales a los que se les ha adicionado carbohidratos de libre disponibilidad (1% de solución de glucosa); iii) suelos naturales a los que se les ha adicionado una mezcla de compuestos nitrogenados de libre disponibilidad (Kg N ha-1) con carbohidratos (1% de solución de glucosa). En cada variante se han testeado diferentes dosis del polímero. Resultados. Los resultados han demostrado que la actividad respiratoria del suelo es independiente de la disponibilidad de compuestos como el nitrógeno o carbono. Tampoco se han observado diferencias significativas entre las diferentes dosis del polímero. Por el contrario, si se observaron diferencias en la producción de CO2. Conclusiones. La lixiviación únicamente se producía cuando los suelos eran enmendados con compuestos únicamente nitrogenados o únicamente sólo carbonosos.

Estudio sobre la lixiviación de cadmio, cromo y plomo de un limpiador lingual en saliva artificial / Study on the leaching of cadmium, chromium and lead from a tongue cleaner onto artificial saliva

Objetivos: Determinar la presencia y concentración de los metales plomo, cadmio y cromo migrados desde el limpiador lingual "Alitest" en saliva artificial, y estimar la exposición oral a estas sustancias. Material y métodos: Diseño pre-experimental y analítico, para cuantificar las sustancias que son liberadas desde el limpiador lingual al contacto con saliva artificial. Los metales fueron analizados por AAS. Se estimaron los valores de exposición por ingesta oral que fueron comparados con valores de ingesta diaria tolerable para cada grupo etario. Resultados: Se cuantificó la migración de cadmio y cromo en concentraciones promedio de 0.008mg/L y 0.437 mg/L, respectivamente. La concentración de plomo estuvo por debajo de los niveles detectables utilizando el método. A partir de estos valores se estimó la ingesta oral para cada grupo etario y se comparó con el valor provisional de ingesta mensual tolerable (PTMI) o Dosis de Referencia (RfD). Conclusiones: Las sustancias se cuantificaron en concentraciones normales, que no excedieron los valores máximos recomendados.

Objectives: To determine the concentration of heavy metals cadmium and chromium leached from the tongue cleaner "Alitest" into artificial saliva and to assess oral exposure of these substances. Material and methods: Analytical pre-experimental design, to determine the amount of those substances released from the tongue cleaner onto artificial saliva and to quantified them by AAS. Assessment of exposure from oral intake values and comparison with the Provisional Tolerable Monthly Intake (PTMI) or Reference Dose (RfD) values. Results: Cadmium and chromium leachated into artificial saliva were quantified in concentrations of 0.008mg/L and 0.437 mg/L, respectively. Lead concentration was under detectable levels using the method. These values were used to estimate the oral intake for each age group and were compared to PTMI or RfD values. Conclusions: The substances were found in normal concentrations, none exceeding the maximum values of PTMI or RfD.

Tolerance to the herbicide clomazone and potential for changes of forest species / Uso de espécies florestais para diminuição do resíduo de clomazone no ambiente

Clomazone has excelled among Brazilian non-target-site herbicides with high environmental impact. Its high solubility in water can result in leaching, contaminating groundwater and watercourses with possible riparian forest degradation. This situation can be mitigated by phytoremediation process. This study aimed to identify tree species tolerant to clomazone aiming to use them in bioremediation programs. Twelve forest species were evaluated: Inga marginata Willd, Handroanthus serratifolius (A.H. Gentry) S. Grose, Jacaranda puberula Chan, Cedrela fissilis Vell, Calophyllum brasiliense Cambess, Psidium myrsinoides Berg, Tibouchina granulosa Cogn, Caesalpinia ferrea Mart ex. Tul, Caesalpinia pluviosa DC, Terminalia argentea Mart & Zucc, Schinopsis brasiliensis Eng and Schizolobium parahyba (Vell). The statistical analysis was performed in a completely randomized block design with four replications. Three clomazone applications were made each 20 days (60, 80 and 100 days after planting); each application was equivalent to one-half of the recommended rate (2.0 L ha-1). The evaluated parameters were plant height, stem diameter, leaf number, leaf area and dry biomass. The forest species survived the clomazone application; and I. marginata, C. ferrea and S. brasiliensis showed increased tolerance to this herbicide, demonstrating potential for phytoremediation of areas contaminated by clomazone.

Entre os herbicidas com elevado impacto ambiental em sítios não alvo no Brasil, o clomazone tem se destacado. A alta solubilidade desse herbicida em água pode resultar em lixiviação, ocasionando contaminação de mananciais de água subterrânea e cursos d'água, com possível degradação de matas ciliares. Esta circunstância pode ser mitigada por meio de processos de fitorremediação. Este trabalho objetivou identificar espécies arbóreas tolerantes ao clomazone visando utiliza-las em programas de biorremediação. Foram avaliadas doze espécies florestais: Inga marginata Willd, Handroanthus serratifolius (A.H. Gentry) S.Grose, Jacaranda puberula Chan, Cedrela fissilis Vell, Calophyllum brasiliense Cambess, Psidium myrsinoides Berg, Tibouchina granulosa Cogn, Caesalpinia ferrea Mart ex. Tul, Caesalpinia pluviosa DC, Terminalia argentea Mart & Zucc, Schinopsis brasiliensis Eng e Schizolobium parahyba (Vell) Blake. Foi utilizado o delineamento em blocos ao acaso com quatro repetições. Foram feitas 3 aplicações do herbicida clomazone com intervalos de 20 dias (aos 60, 80 e 100 dias após o plantio), cada aplicação foi correspondente a metade da dose comercial de 2.0 L ha-1. Foram avaliados a altura da planta, o diâmetro do caule, o número de folhas, a área foliar e o acúmulo de biomassa seca. Constatou-se que todas as espécies sobreviveram à aplicação de clomazone, contudo I. marginata, C. ferrea e S. brasiliensis apresentaram maior tolerância ao herbicida, demonstrando potencial para o uso em programas de fitorremediação de áreas contaminadas pelo clomazone.

Biochemical behavior of bean seeds and grains during storage / Comportamento bioquímico de sementes e grãos de feijão durante o armazenamento

The development of researches about vigor provides greater insight about the physiological behavior of seeds over storage periods. The aim of this study was to evaluate the biochemical changes which occurred in beans stored for 360 days. Analyses were performed at 0, 30, 90, 180, 270, and 360 days after receiving the seeds (S1 and S2) and grains (G1 and G2) of BRS Splendor. The following tests were conducted: water content, electrical conductivity, and chemical composition of the soaking solution, where sugars and ions Fe2+, Zn, Ca2+, Mg2+ and K+ were quantified. The experimental design was completely randomized split-plot and means were compared through Tukey test (p>0.05). Water content decreased after 90 days, and after 180 days reached an average of 16%. The electrical conductivity showed the greatest loss of solute after 90 days. Larger amounts of soluble sugars were found in S1 and G1. The quantities of potassium and calcium decreased after 360 days, while magnesium increased after 90 days of storage. The electrical conductivity test showed no direct relation to the quantification of the investigated ions. The amount and behavior of amino acids and studied ions did not showed relation to the decrease in vigor of beans.

O desenvolvimento de pesquisas sobre vigor proporciona maior conhecimento sobre o comportamento fisiológico das sementes ao longo do armazenamento. O objetivo desse estudo foi avaliar as mudanças bioquímicas ocorridas em feijões armazenados por 360 dias. As análises foram realizadas aos 0, 30, 90, 180, 270 e 360 dias, após o recebimento das sementes e grãos da cultivar BRS Esplendor. Foram realizados os testes de teor de água, condutividade elétrica, e a composição química da solução de embebição, onde os teores de açúcares e íons Fe2+, Zn, Ca2+, Mg2+ e K+ foram quantificados. O delineamento foi inteiramente casualizado em esquema de parcelas subdivididas e as médias comparadas pelo teste de Tukey (p>0,05). A condutividade elétrica apresentou maior perda de solutos aos 90 dias. As quantidades de potássio e cálcio diminuíram até os 360 dias, enquanto o magnésio teve aumento após 90 dias de armazenamento. O teste de condutividade elétrica não apresentou relação direta com a quantificação dos íons investigados. A quantidade e o comportamento dos aminoácidos e dos íons estudados não demonstraram relação com a queda do vigor dos feijões.

Determination on the Content of Copper and Zinc in Tea by Flame Atomic Absorption Spectrophotometry / 沈阳医学院学报

Objective:To determine the content of copper and zinc in tea by flame atomic absorption spectrophotometry and to investigate the influence on the content after leached for different time. Methods:The tea samples were leached for different time by boiling water and then the content of copper and zinc was determinated by flame atomic absorption spectrophotometry. Results:When the leaching time was less than 10 min, the content of copper and zinc increased significantly with the prolongation of the leaching time, while the increase was not obvious when the leaching time was more than 10 min. Copper and zinc showed good linearity in the range of 0.02-0.15 mg/L and 0.05-0.30 mg/L,separately. The recovery was in the range of 98.5%-101.1%for copper and 98.7%-101.2%for zinc with the RSD of 0.8%in copper and zinc (n=9) . Conclusion:The method is suitable to determine the content of copper and zinc in tea. Leaching time can influence the content of copper and zinc in tea significantly.

Comparative Study on Water Soluble Extract and Total Flavonoid Content between Jinzhen Suanzao Teabag and Decoction / 中国药房

OBJECTIVE:To compare the quality control index between Jinzhen Suanzao teabag and decoction,and explore the alternative supplement of teabag to decoction. METHODS:The test sample solutions of Jinzhen Suanzao teabag and decoction were prepared by hot-maceration method and water-decoction method. The contents of water soluble extract and total flavonoids were de-termined and compared between 2 kinds of preparation. The leaching rates of teabag were investigated at different soak time(0,5, 10,15,20,25,30 min) to optimize soaking time. RESULTS:The average content of water soluble extract were 50.56% and 44.45%(P<0.05) respectively for the teabag and decoction. The total flavonoids content were 0.64 mg/g and 0.69 mg/g (P<0.05). The dissolution amount of teabag were increasing and leaching rate increased within first 20 min,and reached balance gradu-ally 25 min later. CONCLUSIONS:According to the convenience of use and results of each index,the difference in quality control index is not great between 2 kinds of preparation. Teabag can be as the supplement of decoction.

Research on the Cytotoxicity of the Heterogeneous Acellular Corneal Stromal Leaching Solution on the CHL Cells / 现代检验医学杂志

Objective To select the largest non-toxic leaching solution concentration through the experimental observation of the cytotoxicity of the ostrich acellular corneal stromal leaching solution to the Chinese hamster lung fibroblasts cells(CHL) for the further chromosome distortion experiment.Methods The leaching solution made from the ostrich acellular corneal stromal material was diluted with concentrate of 1 ∶ 2,1 ∶ 4 and the original concentration were used to culture with the CHL cells,the negative and positive control were also set up at the same time,to evaluate the impact on cell growth after 24 hour by MTT colorimetric method.Results The leaching solution diluted with 1∶4 was non-toxic,and could promote the growth of the cells.Conclusion Combined with the results of classification and cell morphological features,this cytotoxicity test can be used to screen the best benchmark non-toxic concentrations for the chromosome aberration test of the CHL cells.

Preparation of astragalus polvsaccharides-Eudragit S100 colon-specific spray drying powder and evaluation on its in vitro release / 中草药

Objective: To prepare the pH-dependent astragalus polvsaccharides colon-specific spray drying powder, with the intention of controlling drug release in the colon. Methods: Eudragit S100 water dispersion was used as a carrier to prepare astragalus polvsaccharides colon-specific spray drying powder by spray drying method and the in vitro dissolution of spray drying powder was performed. The structure characteristics of spray drying powder was analyzed by SEM. Results: When the ratio of drug to Eudragit S100 was 1:10, the drug in simulated gastric fluid did not release nearly and the accumulative drug-release percent in vitro at 4 h was less than 30.0%; But in the simulated colonic fluid, the accumulated drug release percent reached 90.0% within 1 h. Conclusion: The astragalus polysaccharides colon-specific spray drying powder had the characteristics as a colon-specific delivery system. The preparation process is simple and feasible.

Transporte ascendente da mistura formulada de imazethapyr e imazapic em resposta à profundidade do lençol freático / Upward movement of the formulated mixture of imazethapyr and imazapic in response to height of the water table

Os herbicidas usados na cultura do arroz Clearfield® podem persistir no ambiente e causar danos no arroz não tolerante, cultivado em sucessão. Esse dano pode ser de intensidade variável, dependendo, dentre outros fatores, do movimento ascendente do herbicida para região de absorção do sistema radicular das plantas. O objetivo desta pesquisa foi verificar o efeito da altura do lençol freático no movimento ascendente do herbicida composto pela mistura formulada de imazethapyr e imazapic. Para isso, foram coletados lisímetros de solo com auxílio de tubos de PVC (15x30cm). O herbicida foi aplicado na superfície inferior dos lisímetros, onde foram simulados diferentes profundidades do lençol freático (0, 5, 10, 15 e 25cm da superfície do solo). Os lisímetros permaneceram nessa condição por período de 150 dias, quando foram cortados longitudinalmente, seccionados em porções de 5cm (0-5 a 25-30cm) e realizado bioensaio com a cultivar de arroz não tolerante, IRGA 417. Com os resultados obtidos, foi possível concluir que ocorre movimento ascendente da mistura formulada dos herbicidas imazethapyr e imazapic ao longo do perfil do solo de várzea durante o período da entressafra do arroz irrigado, sendo este maior quando o lençol freático está localizado mais próximo da superfície do solo. O movimento ascendente através da diluição do herbicida na solução do solo ocorre por fluxo de massa através do arraste pela água, transportada por capilaridade para zonas mais superficiais do solo.

The herbicides that use the Clearfield Rice System can persist in the environment and damage non-tolerant rice sowing in rotation. This damage can variable in intensity, depending on, among other factors, of the upward movement of the herbicide to the absorption region of the plant root system. The aim of this research was to verify the effect of the height of the water table in upward movement of the herbicide in intact soil cores. Intact soil cores were collected with PVC tubes 15cm in diameter and 30cm deep. The herbicide was applied on the bottom of the samples, and it was simulated water table depths (0, 5, 10, 15 and 25cm of the soil surface). The intact samples remained in this condition for a period of 150 days, when they were cut into 5cm slices (0-5 a 25-30cm) and bioassay were performed with the non-tolerant rice cultivar. With the results it was conclude that there is upward movement of the formulated mixture of imazethapyr and imazapic herbicides along the paddy soil profile during the fallow and this transport is greater when the water table is located closer to the soil surface. The upward movement by dilution of the herbicide in the soil solution occurs by mass flow through the water transported by capillarity to superficial sites of soil.

Redução na velocidade da nitrificação no solo após aplicação de cama de aviário com dicianodiamida / Reduction of the nitrification rate in the soil after addition of poultry manure with dicyandiamide

A rápida nitrificação do nitrogênio (N) amoniacal de fontes orgânicas e minerais no solo pode resultar em perdas de nitrato (NO3-) para o ambiente. Uma estratégia para a redução dessas perdas envolve o uso de inibidores de nitrificação. O objetivo do presente trabalho foi o de avaliar, em condições de laboratório, a eficiência da dicianodiamida (DCD), presente no produto Agrotain® Plus (AP), em inibir a nitrificação do N amoniacal de cama de aviário (CA) no solo. Foram avaliados cinco tratamentos, sendo um com CA incorporada ao solo, três com CA incorporada ao solo com AP, nas doses de 3,5, 7,0 e 14,0kg ha-1, além de um tratamento somente com solo. A nitrificação foi monitorada através da determinação periódica dos teores de NH4+ e NO3 no solo durante 69 dias. A maior taxa de nitrificação ocorreu no tratamento em que a CA foi incorporada ao solo sem AP. As doses de 3,5 e 7,0kg de AP ha-1 inibiram parcialmente a nitrificação do N amoniacal da CA na fase inicial da incubação, perdendo a eficiência em inibir esse processo no período entre 12 e 27 dias. O tratamento com a maior dose de AP (14kg ha-1) foi aquele em que a DCD exerceu maior efeito inibitório da nitrificação, preservando maior quantidade de NH4+ e retardando o aparecimento de NO3- no solo. Os resultados deste trabalho indicam que a DCD, contida no Agrotain® Plus, reduz a taxa de nitrificação do N amoniacal da CA no solo, o que poderá contribuir à redução das perdas de NO3- para o ambiente.

The fast nitrification of ammoniacal nitrogen (N) of organic and mineral sources in soil can result in losses of nitrate (NO3-) to the environment. One strategy to reduce these losses involves the use of nitrification inhibitors. The objective of this study was to evaluate, in laboratory conditions, the efficiency of Agrotain® Plus (AP), which contains dicyandiamide (DCD), as a nitrification inhibitor of ammoniacal nitrogen from poultry manure (PM) in soil. Were evaluated five treatments, one with PM incorporated into the soil, three with PM incorporated into the soil with AP at the doses of 3.5, 7.0 e 14.0kg ha-1 and one treatment without PM and AP. Nitrification was monitored by measuring changes in soil mineral N (NH4+ and NO3-) periodically over 69 days. The highest rate of nitrification occurred in the treatment in which PM was incorporated into the soil without AP. The doses of 3.5 and 7.0kg ha-1 of AP inhibited partially the nitrification of ammoniacal nitrogen of PM in the initial phase of incubation, losing the ability to inhibit this process in the period between 12 and 27 days. The treatment with the higher dose of AP (14kg ha-1) was on in which the DCD exerted more inhibitory effect on nitrification, preserving most NH4+ and delaying the onset of NO3- in soil. The results of this study indicate that the DCD, contained in the Agrotain® Plus, reduces the nitrification rate of ammoniacal nitrogen from PM in soil, that may contribute to reduce NO3- losses to the environment.

Application of bioleaching to copper mining in Chile

Background: Bioleaching of minerals is a process that allows the treatment of insoluble sulphides and insoluble oxides via hydrometallurgy, as opposed to the more traditional technology of pyrometallurgy. Bioleaching presents several technological, environmental and economic advantages as compared with pyrometallurgy, as well as some limitations. Results: In this work a general panorama of copper mining and biomining, the influence of the most relevant operating variables and their present and future situation in Chile are presented and discussed. Conclusions: Today, Chile plays an important role in the development and commercial application of bioleaching to copper ores. This background information allows predicting a brilliant future for this technology in Chile, as has been forecasted in the last years.

Combined pig slurry and mineral fertilization for corn cultivation

The objective of this work was to evaluate the environmental effects of the use of pig slurry to irrigate the corn crop grown in a typical Red Distroferric Latosol and in leachate composition. Twenty four lysimeters, filled with soil, in a protected environment, received five doses of pig slurry (0; 112.5; 225; 337.5 and 450 m³ ha-1 per growing cycle) combined with two mineral fertilization doses (50 and 75% of the recommended dose - 80 kg ha-1of nitrogen). Corn height and yield were evaluated, as well as nutrients in the soil and in leachate. From the results obtained in the first year of experiment, it was concluded that the concentrations of nitrate increased by increase of pig slurry application, and thus, it would be necessary to develop further studies in medium and long term.