Cadmium toxicity symptoms and uptake mechanism in plants: a review

Abstract Cadmium (Cd) is one of non-essential heavy metals which is released into environment naturally or anthropogenically. It is highly persistent toxic metals that are exceptionally distressing industrial and agriculture activities by contaminating soil, water and food. Its long-duration endurance in soil and water results in accumulation and uptake into plants, leading to the food chain. This becomes a serious global problem threatening humans and animals as food chain components. Living organisms, especially humans, are exposed to Cd through plants as one of the main vegetative food sources. This review paper is concentrated on the symptoms of the plants affected by Cd toxicity. The absorption of Cd triggers several seen and unseen symptoms by polluted plants such as stunted growth, chlorosis, necrosis and wilting. Apart from that, factors that affect the uptake and translocation of Cd in plants are elaborated to understand the mechanism that contributes to its accumulation. By insight of Cd accumulation, this review also discussed the phytoremediation techniques-phytoextraction, phytostimulation, phytostabilization, phytovolatization and rhizofiltration in bioremediating the Cd.

Resumo O cádmio (Cd) é um dos metais pesados não essenciais que é liberado no meio ambiente de forma natural ou antropogênica. São metais tóxicos altamente persistentes que prejudicam excepcionalmente as atividades industriais e agrícolas, contaminando o solo, a água e os alimentos. Sua resistência de longa duração no solo e na água resulta em acúmulo e absorção pelas plantas, levando à cadeia alimentar. Isso se torna um sério problema global que ameaça humanos e animais como componentes da cadeia alimentar. Os organismos vivos, principalmente os humanos, são expostos ao Cd através das plantas como uma das principais fontes de alimento vegetativo. Este artigo de revisão concentra-se nos sintomas das plantas afetadas pela toxicidade do Cd. A absorção de Cd desencadeia vários sintomas visíveis e invisíveis por plantas poluídas, como crescimento atrofiado, clorose, necrose e murcha. Além disso, são elaborados fatores que afetam a absorção e translocação de Cd nas plantas para entender o mecanismo que contribui para o seu acúmulo. A partir do conhecimento do acúmulo de Cd, esta revisão também discutiu as técnicas de fitorremediação - fitoextração, fitoestimulação, fitoestabilização, fitovolatização e rizofiltração na biorremediação do Cd.

Cadmium toxicity symptoms and uptake mechanism in plants: a review / Sintomas de toxicidade de cádmio e mecanismo de absorção em plantas: uma revisão

Cadmium (Cd) is one of non-essential heavy metals which is released into environment naturally or anthropogenically. It is highly persistent toxic metals that are exceptionally distressing industrial and agriculture activities by contaminating soil, water and food. Its long-duration endurance in soil and water results in accumulation and uptake into plants, leading to the food chain. This becomes a serious global problem threatening humans and animals as food chain components. Living organisms, especially humans, are exposed to Cd through plants as one of the main vegetative food sources. This review paper is concentrated on the symptoms of the plants affected by Cd toxicity. The absorption of Cd triggers several seen and unseen symptoms by polluted plants such as stunted growth, chlorosis, necrosis and wilting. Apart from that, factors that affect the uptake and translocation of Cd in plants are elaborated to understand the mechanism that contributes to its accumulation. By insight of Cd accumulation, this review also discussed the phytoremediation techniques-phytoextraction, phytostimulation, phytostabilization, phytovolatization and rhizofiltration in bioremediating the Cd.

O cádmio (Cd) é um dos metais pesados ​​não essenciais que é liberado no meio ambiente de forma natural ou antropogênica. São metais tóxicos altamente persistentes que prejudicam excepcionalmente as atividades industriais e agrícolas, contaminando o solo, a água e os alimentos. Sua resistência de longa duração no solo e na água resulta em acúmulo e absorção pelas plantas, levando à cadeia alimentar. Isso se torna um sério problema global que ameaça humanos e animais como componentes da cadeia alimentar. Os organismos vivos, principalmente os humanos, são expostos ao Cd através das plantas como uma das principais fontes de alimento vegetativo. Este artigo de revisão concentra-se nos sintomas das plantas afetadas pela toxicidade do Cd. A absorção de Cd desencadeia vários sintomas visíveis e invisíveis por plantas poluídas, como crescimento atrofiado, clorose, necrose e murcha. Além disso, são elaborados fatores que afetam a absorção e translocação de Cd nas plantas para entender o mecanismo que contribui para o seu acúmulo. A partir do conhecimento do acúmulo de Cd, esta revisão também discutiu as técnicas de fitorremediação - fitoextração, fitoestimulação, fitoestabilização, fitovolatização e rizofiltração na biorremediação do Cd.

Nitrogen and carbon metabolism evaluation in paricá plants subjected to different cadmium concentrations

The development of anthropogenic activities such as industry, mining, agriculture, urban waste discard has been, the main actions that result in increased contamination by heavy metals in soil, water and air. One of the most harmful metals made available by these activities is cadmium, and even at low concentrations it is very toxic mainly in plant structures. The objective of this work was to verify the biochemical behavior of nitrogen and carbon metabolism in young plants of paricá when submitted to increasing cadmium application. For this, a completely randomized experiment was carried out with five treatments (control, CdCl2 178 µM, CdCl2 356 µM, CdCl2 534 µM, CdCl2 712 µM), with seven replicates, totaling 35 experimental units. The sensitivity of this vegetable to the increasing concentrations of cadmium was evident. The root system it presents'' saw where the most toxic element accumulated, solutes such as carbohydrates, sucrose were affected in their concentrations, mainly in the leaves. The root system saw in its concentrations of glycine betaine a possibility of osmoprotection, but this did not reflect an increase in the concentration of nitrate in both leaf and roots. In the other hand, this fact not observed by the concentration of ammonium that increased in the root system. The results showed that the cadmium was transported to aerial part, however, concentrated mainly in the root system characterizing as a phytoextractor species.

Assessment of phytoremediation potencial of Allium cepa L. in raw sewage treatment / Avaliação do potencial de fitorremediação da Allium cepa L. no tratamento do esgoto bruto

Abstract Whereas the effects of the substances found in domestic sewage on live organisms is important to evaluate the use of plants to remove pollutants from the environment. The objective of this study was to assess the phytoremediation activity of Allium cepa L. (onion) roots exposed to raw sewage, as well as the acute toxic activity of this effluent for the bioindicators A. cepa, through a cytotoxicity test, and Artemia salina L., through a mortality/immobility test. The physicochemical assessments of the sewage were conducted in two scenarios: immediately after collection and after being in contact with onion roots (phytoremediation) for 24 hours. The physicochemical data indicate there was a reduction in nitrogen and phosphorus levels and in biochemical oxygen demand in sewage treated. The results from the cytotoxicity test with A. cepa indicated a reduction in the mitotic cell divisions of the onions treated with the raw sewage. The mortality/immobility test with A. salina indicated that the concentrations with 50 and 100% of raw sewage induced the mortality of the nauplii. Thus, the data suggest new studies that seek greater efficiency, efficacy and viability of onion phytoremediation.

Resumo Considerando os efeitos das substâncias encontradas no esgoto doméstico em organismos vivos, é importante avaliar o uso de plantas para remover poluentes do meio ambiente. O objetivo deste trabalho foi avaliar a atividade de fitorremediação de raízes de Allium cepa L. (cebola) expostas ao esgoto bruto, bem como a atividade tóxica aguda desse efluente para os bioindicadores A. cepa, através de um teste de citotoxicidade, e Artemia salina L., através de um teste de mortalidade/imobilidade. As avaliações físico-químicas do esgoto foram realizadas em dois cenários: imediatamente após a coleta e após contato com raízes de cebola (fitorremediação) por 24 horas. Os dados físico-químicos indicam que houve redução nos níveis de nitrogênio e fósforo e na demanda bioquímica de oxigênio no esgoto tratado. Os resultados do teste de citotoxicidade com A. cepa indicaram uma redução nas divisões celulares mitóticas das cebolas tratadas com o esgoto bruto. O teste de mortalidade/imobilidade com A. salina indicou que as concentrações com 50 e 100% de esgoto bruto induziram a mortalidade dos náuplios. Assim, os dados sugerem novos estudos que busquem maior eficiência, eficácia e viabilidade de fitorremediação das cebolas.

REMOVAL OF AMMONIACAL NITROGEN FROM MUNICIPAL LANDFILL LEACHATE WITH FLOATING Typha domingensis (TYPHACEAE) / Eliminación del nitrógeno amoniacal del lixiviado de vertedero municipal con Typha domingensis (TYPHACEAE) en flotación

ABSTRACT A promising method for the treatment of effluents is the use of floating macrophytes. Ammoniacal nitrogen is a typical compound present in urban landfill leachates and its removal is important due its toxicity to several organisms. Therefore, the study evaluated Typha domingensis survival and nitrification potential artificially floating in domestic solid waste leachate. Plants were exposed for 35 days to leachate (100, 75 and 50 %) and to rainwater with N:P:K (control). Dissolved oxygen (DO) of the treatments was periodically measured, and ammoniacal nitrogen, nitrite and nitrate were analyzed before and after exposure. At the end of the experiment, plant survival rate was calculated. After two weeks, DO increased twice in the control, three times in 50 % leachate, four times in 75 % leachate, and eight times in 100 % leachate. At the end of the experiment, ammoniacal nitrogen was no longer detected, there was a significant reduction of nitrite, and a significant increase of nitrate in the treatments containing leachate. Plant survival was higher in those individuals exposed to 100 % leachate and decreased at lower leachate concentrations: 98 %, 94 %, 92 %, and 86 %. The study demonstrated that the ammoniacal nitrogen concentration of the leachate was not toxic to T. domingensis, and that it was efficient in the removal of this compound from the effluent, indicating that the species may be used artificially floating for the removal of this contaminant from domestic solid waste landfill leachate when in low concentrations.

RESUMEN Un método prometedor para el tratamiento de efluentes es el uso de macrófitas flotantes. El nitrógeno amoniacal es un componente típico de lixiviados de vertederos urbanos y su remoción es importante debido a su toxicidad para diversos organismos. Por eso, el estudio evaluó la supervivencia y el potencial de nitrificación de Typha domingensis flotando artificialmente en lixiviados de residuos sólidos domésticos. Las plantas fueron expuestas por 35 días a lixiviado (100, 75 y 50 %) y al agua de lluvia con N:P:K (control). El oxígeno disuelto (OD) fue medido periódicamente; el nitrógeno amoniacal, el nitrito y el nitrato fueron analizados antes y después de la exposición; al final del experimento, la tasa de supervivencia de las plantas fue calculada. Después de dos semanas, el OD aumentó dos veces en el control, tres veces en el lixiviado 50 %, cuatro veces en el lixiviado 75 % y ocho veces en el lixiviado 100 %. Al final del experimento, el nitrógeno amoniacal no fue más detectado, hubo una reducción significativa de nitrito y un aumento significativo de el nitrato en los tratamientos que contenían lixiviado. La supervivencia de las plantas fue mayor en aquellos individuos expuestos al lixiviado 100 % y se redujo en las menores concentraciones: 98 %, 94 %, 92 % y 86 %. El estudio demostró que la concentración de nitrógeno ammoniacal del lixiviado no fue tóxica para T. domingensis y que ésta fue eficiente en la remoción del compuesto del efluente, indicando que la especie puede ser utilizada flotando artificialmente para la remoción del contaminante de lixiviados de residuos sólidos domésticos en bajas concentraciones.

Biorremediación de mercurio y níquel por bacterias endófitas de macrófitas acuáticas / Bioremediation of mercury and nickel by endophytic bacteria of aquatic macrophytes

RESUMEN La contaminación ambiental se ha categorizado como uno de los principales problemas que afecta la salud de las diferentes formas de vida. Las bacterias endófitas (BE), son capaces de mejorar el estado nutricional de las plantas y remover contaminantes del suelo. La subregión la Mojana funciona como zona de amortización de ríos. En este estudio, se colectaron muestras de macrófitas acuáticas de las ciénagas de Ayapel, San Marcos y San Benito Abad, de los cuales se aislaron bacterias endófitas. Se cuantificó las densidades poblacional de estas bacterias y su respectiva tolerancia a los metales pesados níquel y mercurio. Posteriormente, las cepas tolerantes fueron identificadas molecularmente y se les evaluó su capacidad de promover el crecimiento vegetal. Un total de 182 morfotipos de bacterias endófitas fueron aislados, los mayores promedios de densidad poblacional se obtuvieron en las macrófitas de la ciénaga de San Benito Abad ubicada en las coordenadas coordenadas 8°55'32.81" N y 75°1'13.72" O. Los mayores promedios de morfotipos tolerantes a mercurio y níquel se encontraron en la ciénaga de Ayapel en las coordenadas 8°18'51.10" N y 75°8'8.26" O. Los resultados muestran que los aislados con mayor potencial biotecnológico son BAT6, BAR2 y PAT2, donde los dos primeros tienen una homología del 100% con la especie Lysinibacillus fusifomis y el género Enterobacter, respectivamente, mientras que el tercer aislamiento tuvo una homología del 96% con la especie Burkholderia cepacia. El presente estudio reporta por primera vez la presencia de Lysinibacillus fusifomis y Burkholderia cepacia asociadas a macrófitas en cuerpos cenagosos de Sucre y Córdoba.

ABSTRACT Environmental pollution has been categorized as one of the main problems that affects the health of different life forms. Endophytic bacteria (BE) are able to improve the nutritional status of plants and remove soil contaminants. The Mojana subregion works as a river depreciation zone. In this study, samples of aquatic macrophytes were collected from the marshes of Ayapel, San Marcos and San Benito Abad, from which endophytic bacteria were isolated. The population densities of these bacteria and their respective tolerance to nickel and mercury heavy metals were quantified. Subsequently, the tolerant strains were molecularly identified and their ability to promote plant growth was evaluated, from which the population densities of endophytic bacteria and tolerance to heavy metals were isolated and determined. , to the tolerant isolates and capable of growing in nickel and mercury, plant growth promotion was evaluated, finally they were identified at the molecular level. A total of 182 morphotypes of endophytic bacteria were isolated, the highest population density averages were obtained in the macrophytes of the swamp of San Benito Abad located at the coordinates coordinates 8 ° 55'32.81'' N and 75 ° 1 '13.72 "W , lo. The highest averages of mercury and nickel tolerant morphotypes were found in the Ayapel swamp at coordinates 8 ° 18'51.10'' N and 75 ° 8'8.26 "O. L The results show that the isolates with the greatest biotechnological potential are BAT6, BAR2 and PAT2, where the first two have a 100% homology with the species Lysinibacillus fusifomis and the genus Enterobacter, respectively, while the third isolation had a homology of 96% with the species Burkholderia cepacia show that the isolated BAT6, presented 100% homology with the species of bacteria Lysinibacillus fusifomis; BAR2 100% homology with the bacterial species belonging to the genus Enterobacter and PAT2 96% homology with the species Burkholderia cepacia. The present study reports for the first time the presence of Lysinibacillus fusifomis and Burkholderia cepacia associated with macrophytes in swampy bodies of Sucre and Córdoba.

Volatilization of ammonia in systems of treatment of swine manure with aquatic macrophytes / Volatilização de amônia em sistemas de tratamento de dejetos de suínos com macrófitas aquáticas

Abstract The usage of aquatic plants represents an alternative in the treatment of residues originating from swine. In these systems, one of the N removal methods is the ammonium (NH4 +) uptake and volatilization of ammonia (NH3). In this way, the objective of this work was to evaluate the volatilization rates of NH3 in waste treatment systems swine fluids (SSF) with aquatic macrophytes, as well as the concentration of NH 4+ present in the swine fluids. The experiment was carried out at Campus II/UNOESTE. The treatment systems were composed of 16 boxes of PVC and characterized as: T1 = Control sample 50% of SSF/50% of water; T2 = 50% SSF/50% water + Eichhornia crassipes (Mart.) Solms; T3 = 50% SSF/50% water + Pistia stratiotes L.; T4 = 50% SSF/50% water + Salvinia auriculata Aubl. The design was randomized blocks, with 4 treatments and 4 replicates. The hydrogen potential (pH) and the NH4 + content of the effluent were analyzed weekly, and the volatilization of NH 3 by means of collectors installed in each treatment unit. The presence of aquatic macrophytes promoted the reduction of NH4+ concentration and of the pH values ​​of swine fluids, and this resulted in the reduction of NH3 volatilization rates to the environment, with emphasis on the system with Eichhornia crassipes (Mart.) Solms, which presented the lowest rate of volatilization.

Resumo A utilização de plantas aquáticas representa uma alternativa no tratamento de resíduos oriundos da suinocultura. Nestes sistemas, uma das formas de remoção de nitrogênio (N) é a absorção de amônio (NH4+) pelas plantas, entretanto, também ocorre a volatilização de amônia (NH3). Dessa forma, o objetivo do trabalho foi avaliar as taxas de volatilização de NH3 em sistemas de tratamentos de dejetos líquidos de suínos (DLS) com macrófitas aquáticas, bem como a concentração de NH4+ presente nos dejetos. O experimento foi realizado em área de ambiente aberto no Campus II/UNOESTE. Os sistemas de tratamento foram constituídos de 16 caixas de PVC e caracterizados como: T1 = Testemunha 50% de DLS/50% de água; T2 = 50% de DLS/50% de água + Eichhornia crassipes (Mart.) Solms; T3 = 50% de DLS/50% de água + Pistia stratiotes L.; T4 = 50% de DLS/50% de água + Salvinia auriculata Aubl. O delineamento adotado foi em blocos casualizados, com 4 tratamentos e 4 repetições. Foram analisados o potencial hidrogeniônico (pH) e o teor de NH4 + do efluente semanalmente, e a volatilização de NH3 por meio de coletores instalados em cada unidade de tratamento. A presença das macrófitas aquáticas proporcionou a redução da concentração de NH4+ e dos valores de pH dos dejetos líquidos de suínos, e isto resultou na redução das taxas de volatilização de NH 3 ao meio ambiente, com destaque ao sistema com Eichhornia crassipes (Mart.) Solms, que apresentou a menor taxa de volatilização.

Petroleum contamination and bioaugmentation in bacterial rhizosphere communities from Avicennia schaueriana

ABSTRACT Anthropogenic activity, such as accidental oil spills, are typical sources of urban mangrove pollution that may affect mangrove bacterial communities as well as their mobile genetic elements. To evaluate remediation strategies, we followed over the time the effects of a petroleum hydrocarbon degrading consortium inoculated on mangrove tree Avicennia schaueriana against artificial petroleum contamination in a phytoremediation greenhouse experiment. Interestingly, despite plant protection due to the inoculation, denaturing gradient gel electrophoresis of the bacterial 16S rRNA gene fragments amplified from the total community DNA indicated that the different treatments did not significantly affect the bacterial community composition. However, while the bacterial community was rather stable, pronounced shifts were observed in the abundance of bacteria carrying plasmids. A PCR-Southern blot hybridization analysis indicated an increase in the abundance of IncP-9 catabolic plasmids. Denaturing gradient gel electrophoresis of naphthalene dioxygenase (ndo) genes amplified from cDNA (RNA) indicated the dominance of a specific ndo gene in the inoculated petroleum amendment treatment. The petroleum hydrocarbon degrading consortium characterization indicated the prevalence of bacteria assigned to Pseudomonas spp., Comamonas spp. and Ochrobactrum spp. IncP-9 plasmids were detected for the first time in Comamonas sp. and Ochrobactrum spp., which is a novelty of this study.

Factores clave en procesos de biorremediación para la depuración de aguas residuales. una revisión / Key factors in bioremediation processes for the wastewater treatment. a review

RESUMEN La biorremediación ha demostrado ser una alternativa para establecer nuevos sistemas de depuración de aguas residuales y optimizar los sistemas convencionales existentes. El objetivo de este artículo de revisión es identificar y analizar los factores clave en procesos de biorremediación para la depuración de aguas residuales, a nivel mundial. Se utilizó un método de revisión sistemática de literatura, que incluyó un índice de frecuencia de citación mediante cuartiles (Q). Los resultados most raron la existencia de seis factores clave en procesos de biorremediación para la depuración de aguas residuales: pH (Q3) > temperatura (Q2) > oxígeno (Q2) > nitrógeno (Q2) > fósforo (Q1) > DBO5 (Q1). No existieron diferencias significativas entre las tecnologías de bioaumentación y bioestimulación en relación a los seis factores clave identificados. No se evidenció, en el ámbito mundial, una tendencia en el uso de alguna de estas dos tecnologías; sin embargo, en Asía, Europa y Norte América, se detectó un mayor número de reportes en el uso de la tecnología de bioaumentación y, en Sur América y África, existió mayor empleo de la tecnología de bioestimulación. Las tecnologías de biorremediación (Q1), probablemente, se encontraron en una fase inicial de desarrollo y aplicación en sistemas de depuración para aguas residuales, debido a que las tecnologías químicas (Q2) y físicas (Q2) presentaron un mayor reporte, a nivel mundial. Finalmente, los resultados de esta revisión son un punto de referencia para las instituciones ambientales, encargadas del control de la calidad del agua y diseñadores y operadores en sistemas de depuración.

ABSTRACT Bioremediation has proven to be an alternative to establishing new wastewater treatment systems and optimizing the existing conventional systems. The objective of this review paper is to identify and analyze the key factors in bioremediation processes for wastewater treatment worldwide. A systematic review method of literature was used, which included a citation frequency index using quartiles (Q). The results showed the existence of six key factors in bioremediation processes for wastewater treatment: pH (Q3) > temperature (Q2) > oxygen (Q2) > nitrogen (Q2) > phosphorus (Q1) > BOD5 (Q1). There were no significant differences between bioaugmentation and biostimulation technologies in relation to the six key factors identified. A trend in the use of some of these technologies was not demonstrated at the global level. However, in Asia, Europe, and North America there was a greater report on the use of bioaugmentation technology; and in South America and Africa, there was a greater report of biostimulation technology. Bioremediation technologies (Q1) were probably in an initial phase of development and application in wastewater treatment systems because chemical (Q2) and physical technologies (Q2) presented a larger worldwide report. Finally, the results of this study are a reference point for environmental institutions responsible for water quality control, and designers and supervisors in water treatment systems.

Cadmium tolerance of Typha domingensis Pers. (Typhaceae) as related to growth and leaf morphophysiology / A tolerância ao cádmio por Typha domingensis Pers. (Typhaceae) correlacionada com o crescimento e a morfofisiologia foliar

Abstract Typha domingensis (cattail) is a native macrophyte known by its capacity to tolerate several heavy metals effects and the potential use for phytoremediation. However, in despite that cadmium (Cd) is one of the most toxic pollutants; its effects in T. domingensis biology remain uninvestigated. Thus, the objective of this study was to study the tolerance of T. domingensis to cadmium contamination by evaluating its growth, Cd uptake, leaf anatomy and gas exchange. The experiment was designed using three cadmium concentrations (0, 10 and 50 µM) and ten replicates for 90 days. The cadmium uptake, growth, gas exchange, chlorophyll content and leaf anatomy were evaluated. Data was submitted to ANOVA and Scott-Knott test for P<0.05. Typha domingensis accumulates Cd proportionally to its concentration on the solution and the content of this metal was higher in roots as compared to shoots. Plants showed no significant modifications on growth parameters such as the biomass production, number of leaves, number of clones and the biomass allocation to organs. The photosynthesis, transpiration and chlorophyll content were not modified by Cd. Most anatomical traits evaluated were not modified by the metal but the stomatal density and the proportion of vascular tissues were reduced under 50 µM of Cd. In despite, the leaf anatomy showed no toxicity evidences for any Cd level. The absence of growth reduction and the stability of anatomical and physiological traits give insight about the Cd tolerance of this species. Therefore, T. domingensis is able to overcome Cd toxicity and shows potential for phytoremediation.

Resumo A espécie Typha domingensis (taboa) é uma macrófita nativa conhecida por sua tolerância a vários metais pesados e potencial uso na fitorremediação. Contudo, apesar de que o Cd é um dos poluentes mais tóxicos; Seus efeitos em T. domingensis ainda não foram investigados. Assim, o objetivo desse estudo foi avaliar a tolerância de T. domingensis ao cádmio, avaliando o crescimento, absorção de Cd, anatomia foliar e trocas gasosas. O experimento foi conduzido utilizando três concentrações de Cd (0, 10 e 50 µM) e dez repetições por 90 dias.. O crescimento, trocas gasosas e o teor de clorofila e anatomia foliar foram avaliados. Os dados foram submetidos à ANOVA e ao teste de Scott-Knott para P<0,05. A absorção de cádmio, crescimento, trocas gasosas, teor de clorofila e anatomia foliar foram analisados. As plantas de T. domingensis podem acumular Cd proporcionalmente à sua concentração na solução e o teor deste metal foi maior nas raízes em comparação com a parte aérea. As plantas não apresentam modificações significativas nos parâmetros de crescimento como produção de biomassa, número de folhas, número de clones produzidos e alocação de biomassa nos órgãos. A fotossíntese, transpiração e conteúdo de clorofila não foram afetados de forma significativa pelo Cd. A maioria das características anatômicas avaliadas não apresentou diferenças, mas houve redução na densidade estomática e na proporção de tecidos vasculares na concentração de 50 µM de Cd. A anatomia foliar não mostrou evidências de toxicidade em nenhum dos níveis de Cd. A ausência de redução de crescimento e estabilidade das características anatômicas e fisiológicas caracteriza alta tolerância da espécie ao Cd. Portanto, T. domingensis é capaz de superar a toxicidade do Cd e demostra potencial para fitorremediação.

Phytoremediation of Crude Oil Polluted Agricultural Soil Using Schwenkia americana L. and Spermacoce ocymoides Burm. f.

Aims: To remove hydrocarbons from crude oil polluted agricultural soil using two selected plant species.Study Design:Mature seeds of Schwenkia americanaL. and Spermacoce ocymoidesBurm. f. were propagated onto a sterile unpolluted agricultural soil. Seedlings were transplanted into an 8 kg potted homogenised polluted soil for remediation. Place and Duration of Study:Polluted agricultural soil collected from Ogoniland, Rivers State, Nigeria, Ecological Centre of the University of Port Harcourt Nigeria, between May 2017 and February 2018.Methodology:Standard methods were employed for laboratory analyses. Reagents used were of analytical grades with high purity. Results:Twelves weeks after planting (WAP), total petroleum hydrocarbons (TPH) decreased from 17962.11±1000.00 mg/kg to 117.64±30.27 and 117.45±14.76 mg/kg in S. americanaand for S. ocymoidesremediated groups respectively, while polycyclic aromatic hydrocarbons (PAH) decreased from 440.97±1.00 mg/kg to 120.99±50.05, and 181.97±158.69 mg/kg for S. americanaand for S. ocymoidesremediated groups respectively. While oil content decreased to 1.02±0.09 and 1.15±0.21 ppm for S. americanaand S. ocymoidesremediated groups respectively from an initial 3.19±0.10 ppm recorded at the onset of remediation, organic carbon decreased from 2.78±0.01% to 2.16±0.06 and 2.07±0.18% for S. americanaand S. ocymoidesremediated groups respectively. With regards to TPH, the percentage recovery moved towards normal values (510.27 and 509.02%), however, with regards PAH, the values nosedived indicating a failure in restoration. By 4, 8 and 12 WAP, the treatment restored the values towards normal values (1.08, 7.30, 10.58,10.81 and 14.05%), however, the treatment using S. ocymoides, by 12 WAP, plunged, indicating failure to restore the polluted soil, especially with regards to the oil content, while by 8 and 12 WAP, the treatments restored the polluted soil towards normal values (3.33, 11.11 and 13.33), with regards to the organic carbon.Conclusion:The quality of the crude oil polluted agricultural soil was enhanced through phytoremediation with these plant species. This contention is supported by the diminution of hydrocarbons, organic carbon and the oil content of the remediated groups after the 12 weeks remediation

Variance in Protease, Dehydrogenase, Phosphatase and Respiratory Activities during Phytoremediation of Crude Oil Polluted Agricultural Soil Using Schwenkia americana L. and Spermacoce ocymoides Burm. f.

Aims: To investigate the variation in the activities of some soil enzymes and microbial respiration during phytoremediation of crude oil polluted agricultural soil. Study Design: Indigenous plants of a crude oil polluted agricultural farmland were harvested and identified. Two species (Schwenkia americana L. and Spermacoce ocymoides Burm. f.) were selected for this study. Nursery was set up using sterile soil and mature and viable seeds of selected species, and germinated seedlings were transplanted into an 8 kg potted homogenised polluted soil for remediation. Place and Duration of Study: Polluted agricultural soil from Ogoniland Nigeria, University of Port Harcourt ecological garden, between May 2017 and February 2018. Methodology: Protease activity was determined based on the amino acids released after incubation of soil with sodium caseinate. Phosphatase activities determination was based on determining the degradation extent of ρ-nitrophenol phosphate (PNPP) by the samples. Dehydrogenase activity was determined based on estimation of 2,3,5- triphenyltetrazolium chloride (TTC) reduction to triphenyl formazan (TPF) in soils after incubation. The substrate induced method was adapted to estimate the respiratory activity. Organic matter was determined by weight loss on ignition method. Results: Dehydrogenase activities in remediated groups increased after 4 weeks but decreased at the end of the remediation period. Protease and phosphatase activities, and soil organic matter of remediated groups reduced over time while the soil microbial respiratory activity reduced at the end of 12 weeks remediation. There was a restoration of the polluted soils by the treatments towards normalcy with regards to activities of proteases, acid and alkaline phosphatases, and dehydrogenases. Conclusion: Soil microbial activities can reflect soil quality, and soil enzyme activities can directly reflect the metabolic need and nutrient availability of soil microorganisms. The extracellular enzymes (protease, dehydrogenase, acid and alkaline phosphatase) were shown to vary with crude oil pollution relative to time thus indicating ameliorative effects.

Influence of Lead on In vitro Seed Germination and Early Radicle Development of Acacia auriculiformis Cunn. Ex Benth Species

Aims: To determine the impact of Pb on seed germination and early seedling development in A. auriculiformis species. Place and Duration of Study: The study was carried out in Department of Biology, University Putra Malaysia, between April 2016 and February 2017. Methodology: The concentrations of lead from 0 to 4 g/L (interval of 0.5 g/L) were used. Seeds were germinated in vitro condition. Different parameters were measured including germination percentage, seedling vigour index, tolerance index, germination index, mean germination time and relative injury rate. Results: The noticeable finding of this study reveals that A. auriculiformis seeds have the ability to germination and resist Pb toxicity up to 1.5 g/L. Increasing Pb concentration from 1.5 to 3.5 g/L decreased the germination percentage from 57% to 4% respectively. Conclusion: Acacia auriculiformis seeds germination in a high level of Pb (up to 1.5 g/L) indicated species resistance which probably can be used as Pb hyperaccumulator agent in areas or sites contaminated with this metal.

Presence of Eisenia fetida enhanced phytoremediation of anthracene by Lolium perenne / Presença de Eisenia fetida aumentou a fitorremediação do antraceno por Lolium perene

The efficiency of co-application of Eisenia fetida and ryegrass was evaluated in a process called earthworm-assisted phytoremediation. Anthracene was used as a model compound for polycyclic aromatic hydrocarbons (PAHs). The experiments were conducted on a loamy soil in greenhouse conditions. At the end of the experiment, the soil samples were analyzed for residual anthracene by HPLC. Results showed that, phytoremediation using ryegrass could remove 81% of anthracene; however, the rate of removal was 92% when E. fetida was applied simultaneously. E. fetida alone could also remove the initial concentration of anthracene by 40%. Although ryegrass itself could remove anthracene significantly, the employment of earthworm, together with plant was more efficient than each of them individually. The application of E. fetida could also enhance the growth parameters of ryegrass significantly. In comparison to the control, the presence of E. fetida increased plant dry weight (7.8%), root length (47%), shoots length (32%), and root volume (12%). The number of live earthworms was also increased in the planted pots, indicating the helpfulness of the plant for survival of the earthworm in the PAH-contaminated soil. Although plant and earthworm use completely different mechanisms for anthracene degradation, they improve efficiency and survival of the three-component-system.

A eficiência da co-aplicação de Eisenia fetida e azevém foi avaliada em um processo denominado fitorremediação assistida por minhocas. O antraceno foi usado como um composto modelo para hidrocarbonetos aromáticos policíclicos (PAHs). Os experimentos foram conduzidos em um solo argiloso em condições de estufa. No final da experiência, as amostras de solo foram analisadas quanto ao antraceno residual por HPLC. Os resultados mostraram que, a fitorremediação com azevém pode remover 81% do antraceno; no entanto, a taxa de remoção foi de 92% quando E. fetida foi aplicada simultaneamente. E. fetida sozinha também foi capaz de remover a concentração inicial de antraceno em 40%. Embora o próprio azevém pudesse remover significativamente o antraceno, o emprego da minhoca, juntamente com a planta, foi mais eficiente do que cada um deles individualmente. A aplicação de E. fetida também pode melhorar significativamente os parâmetros de crescimento do azevém. Em comparação com o controle, a presença de E. fetida aumentou o peso seco da planta (7,8%), o comprimento da raiz (47%), o comprimento da parte aérea (32%) e o volume radicular (12%). O número de minhocas vivas também aumentou nos vasos plantados, indicando a utilidade da planta para a sobrevivência da minhoca no solo contaminado com PAH. Embora plantas e minhocas usem mecanismos completamente diferentes para a degradação do antraceno, eles melhoram a eficiência e a sobrevivência do sistema de três componentes.

Eficiência de um sistema piloto utilizando áreas alagadas no pós-tratamento do lixiviado gerado no Aterro Sanitário de Curitiba, Curitiba, Paraná, Brasil / Efficiency of a pilot system using wetlands in the post-treatment of the leachate generated in the Curitiba Landfill, Curitiba, Paraná, Brazil

RESUMO No Aterro Sanitário de Curitiba ocorre o pós-tratamento do lixiviado em áreas alagadas naturais. Para avaliar o papel das macrófitas nesse pós-tratamento, foi desenvolvido um sistema piloto. Dessa forma, o objetivo do presente estudo foi avaliar a eficiência do sistema piloto utilizado para o pós-tratamento do lixiviado desse aterro sanitário. O sistema foi construído com duas caixas d'água: na primeira foi colocada a macrófita Echinochloa polystachya e na segunda, Eichhornia crassipes. O sistema operou em batelada e foi realizado um ciclo de sete dias. Para o monitoramento do sistema foram efetuadas coletas e análises do lixiviado, do substrato e das macrófitas. A eficiência do sistema no pós-tratamento do lixiviado foi de 72% para demanda bioquímica de oxigênio, 30% para demanda química de oxigênio, 76% para fósforo total e fósforo inorgânico, 38% para nitrato, 33% para nitrito, 58% para nitrogênio amonical, 44% para nitrogênio orgânico e 13% para zinco.

ABSTRACT In the Curitiba Landfill the post-treatment of the leachate occurs in natural wetlands. In order to evaluate the role of macrophytes in this post-treatment, it was developed a pilot system. Thus, the objective of this study was to evaluate the effectiveness of the pilot system in the post-treatment of the leachate in this landfill. The system was built with two water tanks: the macrophyte Echinochloa polystachya was placed in the first one; and the Eichhornia crassipes was placed in the second one. The system operated in batch in a seven-day cycle. For monitoring the system, samples were collected, and analyses of the leachate, the substrate, and the macrophytes were performed. The efficiency of the system in the post-treatment of the leachate was 72% for biochemical oxygen demand, 30% for chemical oxygen demand, 76% for total phosphorus and inorganic phosphorus, 38% for nitrate, 33% for nitrite, 58% for ammoniacal nitrogen, 44% for organic nitrogen, and 13% for zinc.

Accumulation of copper by the aquatic macrophyte Salvinia biloba Raddi (Salviniaceae) / Acumulação de cobre pela macrófita aquática Salvinia biloba Raddi (Salviniaceae)

Abstract Aquatic macrophytes have properties and mechanisms which are useful for the removal of substances in solution, commonly used in phytoremediation processes in aquatic environments. This study evaluated the performance of copper (Cu) accumulation by Salvinia biloba Raddi (Salviniaceae) in different metal concentrations (1, 3 and 5 µg mL-1), as well as the control treatment, measured at intervals of 0, 7 and 14 days under laboratory conditions, with control as to pH and luminosity. After the experiment, the S. biloba biomass was washed, kiln dried, crushed and subjected to the process of digestion, and subsequently the accumulated copper content was determined by atomic absorption spectroscopy. The results showed that S. biloba is apt at accumulating copper, varying significantly between different treatments and days of exposure to the contaminant, as well as its interaction (treatment × days). The highest accumulation values were observed in treatment with 5 µg mL-1, which at 14 days, with 11,861 µg g-1 of copper. We observed symptoms of toxicity and mortality in plants, probably indicating the effect of copper on the species when at high levels. Salvinia biloba is an efficient species in the removal of copper in solution, its recommendation as a remediating agent in aquatic ecosystems being possible.

Resumo Macrófitas aquáticas apresentam propriedades e mecanismos úteis à remoção de substâncias presentes em solução, comumente, utilizadas em processos de fitorremediação de ambientes aquáticos. Este estudo avaliou o desempenho de acumulação de cobre (Cu) por Salvinia biloba Raddi (Salviniaceae) em diferentes concentrações do metal (1, 3 e 5 µg mL-1), além do tratamento controle, avaliados em intervalos de 0, 7 e 14 dias, sob condições laboratoriais, com controle de pH e luminosidade. Após o experimento a biomassa de S. biloba, foi lavada, seca em estufa, triturada e submetida ao processo de digestão, sendo, posteriormente, o teor de cobre acumulado determinado por espectroscopia de absorção atômica. Os resultados evidenciaram que S. biloba é hábil em acumular cobre em sua biomassa, variando significativamente entre os diferentes tratamentos e dias de exposição ao contaminante, bem como por sua interação (tratamentos × dias). Os maiores teores de acúmulo foram observados no tratamento com 5 µg mL-1, que aos 14 dias apresentou até 11.861 µg g-1 de Cu. Observamos sintomas de toxicidade e mortalidade nas plantas, evidenciando, provavelmente, o efeito do cobre sobre a espécie quando em elevados níveis. Salvinia biloba é uma espécie eficiente na remoção do cobre em solução, sendo possível sua recomendação como agente de remediação em ecossistemas aquáticos.

Investigating lead and zinc uptake and accumulation by Stipa hohenackeriana trin and rupr. in field and pot experiments / Investigação sobre a captação e acúmulo de chumbo e zinco por Stipa hohenackeriana trin. & rupr. em experimentos de campo e em vaso

This study was conducted to evaluate Pb and Zn uptake, mobility, and accumulation in Stipa hohenackeriana using field soil in pot and field experiments. Moreover, the effects of Municipal Solid Waste Compost (MSWC) (0, 1, and 2%) and Nano-Silica (NS) (0, 250, and 500 mg/kg) on Stipa biomass, Pb and Zn availability in the soil, and Pb and Zn uptake and accumulation were studied using pot experiments. Samples of soil, root, and shoots of Stipa were collected from field and greenhouse and after drying, extraction of Pb and Zn was done by acid digestion. Bio- Concentration Factor (BCF) and Translocation Factor (TF) were calculated to determine Pb and Zn phytoremediation efficiency. The amount of Zn and Pb remediation by Stipa from soil was determined by remediation factor (RF). The results of field experiments showed the Pb and Zn level decreased in the order of: soil >shoot>root. Results of the pot experiments also showed that plants grown in NS500-amended pots had 33% and 32% higher Pb in roots and shoots compared to control pots, respectively. In comparison, roots Pb concentration in pots amended with MSWC1% and MSWC2% decreased 22.4% and 1.7%, respectively. Roots and shoots Zn concentration in NS500-amended pots was 5.6% and 6.5% higher, respectively. However, root Zn concentration in treatments of MSWC1% and MSWC2% decreased 52.3% and 39.4%, respectively. Shoots Zn concentration decreased 52.5% and 40.0%, respectively. Although MSWC decreased the uptake and accumulation of Pb and Zn in Stipa roots and shoots, it improved the plant growth and consequently increased RF and soil remediation compared to the NS. Thus, it seems that applying MSWC and NS simultaneously can be a suitable strategy for the purpose of improving phytoremediation capability of Stipa in the Pb and Zn contaminated soils. In general, Stipa can be a suitable candidate for the accumulation of heavy metals, especially for Pb and Zn contaminated soils.

Este estudo foi conduzido para avaliar a absorção, mobilidade e acumulação de Pb e Zn em Stipa hohenackeriana em experiências usando solo de campo em vaso e em campo. Além disso, os efeitos do Composto Municipal de Resíduos Sólidos (MSWC) (0, 1 e 2%) e de nanopartículas de sílica (NS) (0, 250 e 500 mg/kg) na biomassa de Stipa, na disponibilidade de Pb e Zn no solo, e na absorção e acúmulo de Pb e Zn foram estudados usando experiências em vaso. Amostras de solo, raiz e brotos de Stipa foram coletadas do campo e da estufa e, após a secagem, a extração de Pb e Zn foi feita por digestão ácida. O Fator de Bioconcentração (BCF) e o Fator de Translocação (TF) foram calculados para determinar a eficiência de fitorremediação de Pb e Zn. A quantidade de remediação de Zn e Pb pela Stipa a partir do solo foi determinada pelo Fator de Remediação (RF). Os resultados das experiências de campo mostraram que o nível de Pb e Zn diminuiu na seguinte ordem: solo > broto > raiz. Os resultados das experiências em vaso também mostraram que as plantas cultivadas em vasos corrigidos com NS500 apresentaram teores de Pb 33% e 32% maiores em raízes e brotos em comparação com vasos de controle, respectivamente. Em comparação, a concentração de Pb em raízes em vasos corrigidos com MSWC1% e MSWC2% diminuiu 22,4% e 1,7%, respectivamente. A concentração de Zn em raízes e brotos em vasos corrigidos com NS500 foi de 5,6% e 6,5% maior, respectivamente. No entanto, a concentração de Zn da raiz nos tratamentos de MSWC1% e MSWC2% diminuiu 52,3% e 39,4%, respectivamente. A concentração de Zn nos brotos diminuiu 52,5% e 40,0%, respectivamente. Embora o MSWC tenha diminuído a absorção e acumulação de Pb e Zn nas raízes e brotos de Stipa, melhorou o crescimento da planta e consequentemente aumentou o RF e a remediação do solo em relação ao NS. Assim, parece que aplicar MSWC e NS simultaneamente pode ser uma estratégia adequada com o objetivo de melhorar a capacidade de fitorremediação de Stipa nos solos contaminados com Pb e Zn. Em geral, a Stipa pode ser um candidato adequado para a acumulação de metais pesados, especialmente para solos contaminados com Pb e Zn.

Differential behavior of the summer cover crops in the absorption and translocation of copper / Comportamento diferencial das plantas de cobertura de verão na absorção e translocação do cobre

ABSTRACT: Phytoremediation is an alternative technique used to treat copper-contaminated soils. The objective of this research was to explore the behavior of nine summer cover crops regarding the growth, absorption and translocation of copper in soils with contamination levels exceeding the Value of Prevention, with a view to selecting plants for phytoremediation programs. In the experiments the Cambisol was contaminated with copper, added in doses of 0, 100, 200, 400, 500 and 600mg kg-1, in which the following nine plants were cultivated under greenhouse conditions: Canavalia ensiformis, Cajanus cajan, Dolichos lablad, Mucuna cinereum, Mucuna aterrima, Crotalaria juncea, Crotalaria spectabilis, Pennisetum glaucum and Paspalum notatum. At 90 days after sowing the plants were evaluated for dry mass of shoot and root, Cu, N, P, K, Ca, Zn, and Fe levels in the shoot and Cu in the roots. High soil Cu levels induced a decline in the phosphorus absorption by the plants. Canavalia ensiformis displayed high potential for phytoextraction as these plants could translocate high copper concentrations to the aerial plant parts, while the Mucuna cinereum and M. aterrima are indicated for the copper phytostabilization programs, due to the high copper accumulation in their root systems.

RESUMO: A fitorremediação é uma alternativa para o tratamento de solos contaminados com cobre. O objetivo do trabalho foi conhecer o comportamento de nove plantas de cobertura de verão quanto ao crescimento, absorção e translocação do cobre em solos com contaminação acima dos Valores de Prevenção, com vistas a seleção de plantas para programas de fitorremediação. Um Cambissolo foi contaminado com doses de 0, 100, 200, 400, 500 e 600mg kg-1 de cobre e cultivado em casa de vegetação com nove plantas: Canavalia ensiformis, Cajanus cajan, Dolichos lablad, Mucuna cinereum, Mucuna aterrima, Crotalaria juncea, Crotalaria spectabilis, Pennisetum glaucum e Paspalum notatum. Aos 90 dias após a semeadura as plantas foram avaliadas quanto à produção de massa seca de parte aérea e raízes, teores de Cu, N, P, K, Ca, Zn, e Fe na parte aérea e de Cu nas raízes. As altas concentrações de Cu no solo reduziram a absorção de fósforo pelas plantas. O feijão-de-porco apresenta potencial para a fitoextração, pois apresentou translocação de altas concentrações de cobre para os tecidos aéreos, enquanto que as mucunas preta e cinza são indicadas para programas de fitoestabilização de cobre, pois acumularam elevada concentração de cobre no sistema radicular.

Uso de Leersia hexandra (Poaceae) en la fitorremediación de suelos contaminados con petróleo fresco e intemperizado / Use of Leersia hexandra (Poaceae) for soil phytoremediation in soils contaminated with fresh and weathered oil

ResumenLa industria petrolera ha generado derrames crónicos de petróleo y su acumulación en Gleysoles en zonas anegadas en el estado de Tabasco, en el sureste de México. El anegamiento es un factor que limita el uso de tecnologías de remediación por el alto costo y los bajos niveles de degradación del petróleo, sin embargo, Leersia hexandra Sw. es un pasto que crece en estas zonas contaminadas con petróleo intemperizado. El objetivo del estudio fue evaluar la densidad de bacterias, producción de biomasa vegetal y fitorremediación de L.hexandra en suelo contaminado con petróleos fresco e intemperizado, bajo condiciones experimentales de anegamiento. Se realizaron dos experimentos (E1 y E2) en un túnel de plástico. El E1 se basó en ocho dosis: 6 000, 10 000, 30 000, 60 000, 90 000, 120 000, 150 000 y 180 000 mg kg-1 base seca (b.s.) de hidrocarburos totales de petróleo fresco (HTPF), y en el E2 se evaluaron cinco dosis: 14 173, 28 400, 50 598, 75 492 y 112 142 mg kg-1 b. s. de hidrocarburos totales de petróleo intemperizado (HTPI), con ocho repeticiones en cada experimento, además se utilizó un testigo con 2 607 mg kg-1 b. s. de HTP de origen biogénico. Las variables evaluadas a los tres y seis meses fueron 1) densidad microbiana de las bacterias fijadoras de nitrógeno de vida libre totales (BFN), del grupo Azospirillum (AZP) y Azotobacter (AZT), por cuenta viable en placa seriada; 2) producción de materia seca total (MS), se cuantificó por el peso seco por gravimetría, y 3) el porcentaje de descontaminación de los hidrocarburos (DSC) por extracción en equipo soxhlet. En suelos con HTPF, la población de BFN, AZP y AZT se estimuló hasta cinco veces más que el tratamiento testigo a los tres y seis meses; sin embargo, concentraciones de 150 000 y 180 000 mg kg-1 b. s. inhibieron entre un 70 y 89 % la densidad bacteriana. A su vez, en suelos con PI, la inhibición se registró hasta en un 90 %, a excepción del tratamiento con 14 173 mg kg-1 b. s., el cual estimuló las BNF y AZT en 2 y 0.10 veces más que testigo, respectivamente. La producción de MS fue continua en los experimentos hasta los seis meses, con valores de 63 y 89 g en PF y PI, respectivamente; sin diferencias significativas con el testigo (p ≤ 0.05). El DSC alcanzó valores del 66 % al 87 % en HTPF como HTPI a los seis meses, respectivamente. Estos resultados demuestran la habilidad del L. hexandra para desarrollar una rizósfera con alta densidad de BFN, producir biomasa vegetal y fitorremediar Gleysoles con petróleo fresco e intemperizado en ambientes tropicales inundados.

Abstract:The oil industry has generated chronic oil spills and their accumulation in wetlands of the state of Tabasco, in Southeastern Mexico. Waterlogging is a factor that limits the use of remediation technologies because of its high cost and low levels of oil degradation. However, Leersia hexandra is a grass that grows in these contaminated areas with weathered oil. The aim of the study was to evaluate the bacteria density, plant biomass production and phytoremediation of L. hexandra in contaminated soil. For this, two experiments in plastic tunnel were performed with fresh (E1) and weathered petroleum (E2) under waterlogging experimental conditions. The E1 was based on eight doses: 6 000, 10 000, 30 000, 60 000, 90 000, 120 000, 150 000 and 180 000 mg.kg-1 dry basis (d. b.) of total petroleum hydrocarbons fresh (TPH-F), and the E2, that evaluated five doses: 14 173, 28 400, 50 598, 75 492 and 112 142 mg. kg-1 d. b. of total petroleum hydrocarbons weathered (TPH-W); a control treatment with 2 607 mg.kg-1 d. b. was used. Each experiment, with eight replicates per treatment, evaluated after three and six months: a) microbial density of total free-living nitrogen-fixing bacteria (NFB) of Azospirillum (AZP) and Azotobacter group (AZT), for viable count in serial plate; b) dry matter production (DMP), quantified gravimetrically as dry weight of L. hexandra; and c) the decontamination percentage of hydrocarbons (PDH) by Soxhlet extraction. In soil with TPH-F, the NFB, AZP y AZT populations were stimulated five times more than the control both at the three and six months; however, concentrations of 150 000 and 180 000 mg.kg-1 d. b. inhibited the bacterial density between 70 and 89 %. Likewise, in soil with TPH-W, the FNB, AZP and AZT inhibitions were 90 %, with the exception of the 14 173 mg.kg-1 d. b. treatment, which stimulated the NFB and AZT in 2 and 0.10 times more than the control, respectively. The DMP was continued at the six months in the experiments, with values of 63 and 89 g in fresh and weathered petroleum, respectively; had no significant differences with the control (p≤0.05). The PDH reached values of 66 to 87 % both TPH-F and TPH-W at six months, respectively. These results demonstrated the ability the L. hexandra rhizosphere to stimulate the high NFB density, vegetal biomass production and phytoremediation of contaminated soils (with fresh and weathered petroleum), in a tropical waterlogging environment. Rev. Biol. Trop. 65 (1): 21-30. Epub 2017 March 01.

Distribution and Speciation of Lead in Moss Collected from a Lead-Zinc Mining Area by Micro-X-Ray Fluorescence and X-Ray Absorption Near Edge Structure Analysis / 分析化学

Moss has high tolerance and accumulating capacity to heavy metal.In this study, the distribution of heavy metal elements in moss sampled from lead-zinc mine was analyzed by X-ray fluorescence spectrometry.The speciation of lead was analyzed by X-ray absorption near-edge spectroscopy.Research showed that the contents of Pb, Zn, Cd and As in the moss of the mining area were extremely high, and their maximum concentration were 1.06 mg/g , 1.23 mg/g, 30.5 μg/g, 13.2 μg/g, respectively.Besides, the shoots especially the new tissue of the moss were the major sites for accumulation and storage of heavy metals.The micro-distribution characteristics varied among Hypnum plumaeforme and Brachytheciumprocumbens, indicating the difference of different species of moss in absorption pathway, accumulation and tolerance mechanisms for heavy metal.Linear combination fitting results indicated that the main lead speciation in moss was lead phosphate (78%) and lead oxide (22%), which suggested that the precipitation of lead phosphate might be the main mechanism of tolerance for moss.