Potential of vegetal species for phytoremediation of soil one contaminate by arsenic

O arsênio (As) é encontrado na natureza associado aos minérios de prata, ouro, antimônio, cobalto e de níquel. Existem vários casos de intoxicação e morte de milhares de pessoas contaminadas por arsênio em diversos países do mundo. No Brasil existem ocorrências de áreas com elevadas concentrações deste metalóide no Quadrilátero Ferrífero de Minas Gerais, no delta do rio Amazonas e Santana no Amapá, entre outras. Tendo em vista o impacto que o arsênio pode causar no ambiente é de grande importância o desenvolvimento de técnicas para a descontaminação de áreas com elevadas concentrações deste metalóide. O presente estudo teve como finalidade avaliar o potencial de diferentes espécies de leguminosas herbáceas - crotálaria (Crotalaria spectabilis Roth.), feijão de porco (Canavalia ensiformis L.), mucuna preta (Stilozobium aterrinum Piper & Tracy), forrageiras herbáceas - estilosante (Stylosanthes humilis HBK), amendoim forrageiro (Arachis pintoi Krapov. & Gregory), azevém (Lolium multiflorum L.) aveia preta (Avena sativa L.), leguminosas arbustivas - feijão guandu (Cajanus cajan L.), sesbania (Sesbania virgata Cav.), leucena (Leucaena leucocephala L.) e espécies de eucaliptos - Eucaliptus grandis Hill, E. cloeziana (F. Muell), E. urophylla (S.T. Black), Corymbia citriodora (Hill & Johnson) (Eucalyptus citriodora Hook) para programas de fitorremediação de áreas contaminadas por arsênio. Os ensaios foram conduzidos em casa de vegetação em blocos casualizados com três repetições. Amostras de Latossolo Vermelho Amarelo foram incubadas por 15 dias com diferentes doses de As 0,0; 50; 100 e 200 mg dm-3 para as espécies herbáceas e arbustivas e de 0,0; 50; 100; 200 e 400 mg dm-3 para as espécies de eucaliptos, as quais resultaram em teores recuperados (Mehlich 3) de 0,0; 12,9; 26,8; 58,7 e 128,8 mg dm-3, respectivamente. Como fonte de As foi utilizado o arsenato de sódio (Na2HAsO4+7H2O). Após o período de incubação, realizou-se a semeadura das espécies herbáceas e arbustivas, sendo que para as espécies de eucaliptos realizou-se o transplantio de mudas com aproximadamente dois meses de idade, e após a germinação e transplantio, realizou-se as adubações com macro e micronutrientes. Aos 65 (herbáceas) e 90 (arbustivas e eucaliptos) dias após a semeadura e/ou transplantio as plantas foram avaliadas quanto à altura, diâmetro, matéria seca de raízes e parte aérea. As plantas foram separadas em folhas jovens, intermediárias e basais, caule, ramos, pecíolo e raízes, de acordo com as espécies. Determinaram-se os teores de arsênio nas diferentes partes das plantas, bem como, o conteúdo e índice de translocação de As para cada espécie. Por meio de análises de regressão foram estimados os teores críticos (TC) de As disponíveis no solo que proporcionaram redução de 50 % da matéria seca produzida em relação às plantas testemunhas. As espécies avaliadas mostraram comportamento diferenciado quanto à tolerância ao As. As plantas de mucuna preta, sesbania, leucena, azevém e E. grandis não manifestaram sintomas morfológicos visuais de toxicidade e apresentaram valores de TC no solo significativamente superiores aos observados para as demais espécies no período de tempo estudado. Os elevados conteúdos de arsênio nas raízes dessas espécies sugerem a atuação de mecanismo diferenciado de acumulação e translocação do metalóide aos tecidos da parte aérea. As espécies feijão guandu, feijão de porco, aveia forrageira e E. cloeziana apresentaram-se sensíveis exibindo lesões em suas folhas basais na maior dose de arsênio testada, mostrando potencial para serem utilizadas como plantas bioindicadores de efeitos em solos contaminados por arsênio. Por outro lado, as espécies mucuna preta, azevém, amendoim, estilosante e E. urophylla apresentam alta tolerância com potencial para fitoestabilização. Por último, as plantas de E. grandis, crotalária e Corymbia citriodora mostratam-se com potencial para serem utilizadas na fitoextração, no entanto, trabalhos mais conclusivos são necessários em condições de campo para verificar a potencialidade dessas espécies por maior período de exposição.Arsenic is found in the nature associated with ores from silver, gold, antimonium, cobalt and nickel. Intoxication and death in thousands persons caused by arsenic were related in different countries of the word. In Brazil there is high concentrations areas of this metalloid at Quadrilátero Ferrífero of Minas Gerais State, at delta of Amazonas river and Santana in Amapá State, among others. Considering the impact that arsenic may cause on the environment it is very important to set techniques to remediate arsenic high content areas. This work had the aim to evaluate the potential of different species of legumes herbaceous - velvetbean (Stizolobium aterrimum Piper & Tracy), jack bean (Canavalia ensiformis (L.)) and crotalaria (Crotalária spectabilis Roth.), of foragers herbaceous - townsville stylo (Stylosanthes humilis), forage peanuts (Arachis pintoi), oat (Avena strigosa Schreb), and ryegrass (Lolium multiflorum Lam.), of legumes shrubs - jack bean (Cajanus cajan L.), sesbania (Sesbania virgata Cav.), leucena (Leucaena leucocephala Lam. (De Witt)), and eucalyptus species - Eucaliptus grandis Hill, E. cloeziana (F. Muell), E. urophylla (S.T. Black), Corymbia citriodora (Hill & Johnson) (Eucalyptus citriodora Hook) to phytoremediation programs of arsenic contaminated areas. Samples of Red-Yellow Latossol were incubated with different doses of As: 0; 50; 100 and 200 mg dm-3 to herbaceous and shrubs species and 0,0; 50; 100; 200 e 400 mg dm-3 to eucalyptus species. These doses resulted in 0,0; 12,9; 26,8; 58,7 e 128,8 mg dm-3 of available arsenic by Mehlich-3, respectively. Sodium arsenate (Na2HAsO4+7H2O) was the As source used for all experiments. After the incubation time herbaceous and shrubs species were seeded and to eucalyptus species the seedlings transplantated two months of seedling. The macro and micronutrients fertilizations were done after the seeded or transplantation. After sixty five days to herbaceous and 90 days to shrubs and eucalyptus species of seeding and transplantation, plants were evaluated to height, diameter and root and shoot biomass. Arsenic content in young, intermediated, and old leaves, steam and roots, and As-translocation index were determined. By regression analysis we estimated the values of soil critical available arsenic (TC) that reduced 50% of biomass production. Species showed different behavior to arsenic tolerance: velvetbean, sesbania, leucena, ryegrass and E. grandis did not show As-toxic morphologic symptoms, as injuries in leaves, and showed higher soil TC values than others species. High As content in roots from these species suggests the action of different mechanisms of accumulation and translocation of As in the shoot tissues. Jack bean, jack bean, oat forager and E. cloeziana showed injuries in bottom leaves when exposed to the higher dose of As, showing potential as bioindicators plants of arsenic-contaminated soils. On the other hand, species as velvetbean, ryegrass, forage peanuts, townsville stylo and E. urophylla showed high Astolerance with potential to arsenic-phytostabilization plants. E. grandis, crotalária e Corymbia citriodora showed potential to be used as As-phytoextraction plants. Nevertheless, more conclusive works, in field conditions and more exposition time, to set the potential of these species must be done.Coordenação de Aperfeiçoamento de Pessoal de Nível Superio

Behavior of Eucalyptus urophylla and Eucalyptus citriodora Seedlings Grown in Soil Contaminated by Arsenate

ABSTRACT: Persistent areas of tailings and deposits from coal and gold mining may present high levels of arsenic (As), mainly in the arsenate form, endangering the environment and human health. The establishment of vegetation cover is a key step to reclaiming these environments. Thus, this study aimed to evaluate the potential of Eucalyptus urophylla and E. citriodora seedlings for use in phytoremediation programs of arsenate-contaminated areas. Soil samples were incubated at increasing rates (0, 50, 100, 200 and 400 mg dm -3 ) of arsenic (arsenate form, using Na 2 HAsO 4 ) for 15 days. The seedlings were produced in a substrate (vermiculite + sawdust) and were transplanted to the pots with soil three months after seed germination. The values of plant height and diameter were taken during transplanting and 30, 60 and 90 days after transplanting. In the last evaluation, the total leaf area and biomass of shoots and roots were also determined. The values of available As in soil which caused a 50 % dry matter reduction (TS 50% ), the As translocation index (TI) from the roots to the shoot of the plants, and its bioconcentration factor (BF) were also calculated. Higher levels of arsenate in the soil significantly reduced the dry matter production of roots and shoots and the height of both species, most notably in E. urophylla plants. The highest levels of As were found in the root, with higher values for E. citriodora (ranging from 253.86 to 400 mg dm -3 ). The TI and BF were also reduced with As doses, but the values found in E. citriodora were significantly higher than in E. urophylla. E. citriodora plants presented a higher capacity to tolerate As and translocate it to the shoot than E. urophylla. Although these species cannot be considered as hyperaccumulators of As, E. citriodora presented the potential to be used in phytoremediation programs in arsenate-contaminated areas due to the long-term growth period of this species

Comportamento produtivo e características pós-colheita de híbridos comerciais de melão amarelo, cultivados nas condições do litoral do Ceará Yield and postharvest quality of melon hybrids cultivated at the east coast of Ceará State

Desenvolveu-se, este trabalho, em condições de campo na Estação Experimental da Embrapa/ Agroindústria Tropical, em Pacajus - CE, no período de setembro a dezembro de 2000, objetivando caracterizar a produtividade e a qualidade dos frutos de nove híbridos de melão amarelo, nas condições do litoral leste do Estado do Ceará. O delineamento experimental utilizado foi o de blocos casualizados, com nove tratamentos e cinco repetições. Os tratamentos foram constituídos dos híbridos comerciais de melão amarelo descritos a seguir: Gold Pride, Gold Star, TSX 32096, Yellow Queen, PX 4910606, AF 682, XPH 13021, AF 646 e Gold Mine. Avaliou-se produção total, massa média de frutos na primeira colheita, sólidos solúveis (SS), resistência de polpa e classificação dos frutos. Para todas as variáveis analisadas observaram-se diferenças significativas entre os híbridos, com exceção do teor de SS. Os híbridos Gold Pride, Gold Star, XPH 13021 e Gold Mine apresentaram maiores produtividades, com média de 32 t/ha. O Gold Mine apresentou maior massa média de fruto (1,5 kg), diferindo significativamente dos híbridos Gold Pride (1,14 kg), AF 646 (1,02 kg), AF 682 (1,09 kg) e PX 4910606 (1,11 kg), que apresentaram os menores valores médios. Os frutos dos híbridos Gold Mine, TSX 32096, PX 4910606, XPH 13021 e AF 682 apresentaram os maiores valores de SS e resistência de polpa, enquanto, o Yellow Queen e o AF 646 apresentaram os menores valores. Os híbridos Gold Mine, Gold Star, XPH 13021 e Gold Pride destacaram-se pelas maiores produtividades de frutos comercializáveis.In order to evaluate fruit yield and quality of yellow melon, an assay was carried out at EMBRAPA/ Tropical Agroindustry Research Station, in Pacajus-CE, in the period from September to December, 2000. Nine melon hybrids were screened under field conditions at the east coast of Ceará State. The experimental layout was a randomized complete block design with nine treatments and five replicates. The treatments were comprised of the following commercial hybrids: Gold Pride, Gold Star, TSX 32096, Yellow Queen, PX 4910606, AF 682, XPH 13021, AF 646 and Gold Mine. Fruit yield, average fruit weight at the first harvest, total soluble solids (SS) content, pulp firmness and fruit classification were evaluated. Significant differences between hybrids were observed for all the analyzed variables, except for SS content. The hybrids Gold Pride, Gold Star, XPH 13021 and Gold Mine presented the largest yields, 32 t/ha in average. Gold Mine had the largest average fruit weight (1.5 kg), statistically differing from those of Gold Pride (1.14 kg), AF 646 (1.02 kg), AF 682 (1.09 kg) and PX 4910606 (1.11 kg). Regarding to fruit total SS content and pulp firmness, Gold Mine, TSX 32096, PX 4910606, XPH 13021 and AF 682 had the best results, different from the Yellow Queen and AF 646 which showed the lowest values. The hybrids Gold Mine, Gold Star, XPH 13021 and Gold Pride had high marketable yield

Potencial de quatro espécies herbáceas forrageiras para fitorremediação de solo contaminado por arsênio

A fitorremediação de solos e substratos contaminados por elementos tóxicos tem despertado crescente interesse entre pesquisadores e técnicos. Particularmente em relação ao As, o obstáculo ao emprego desta técnica é o pequeno número de espécies identificadas capazes de acumular este elemento. O objetivo deste trabalho foi avaliar o potencial de plantas de estilosante (Stylosanthes humilis HBK), amendoim (Arachis pintoi Krapov. & Gregory), aveia (Avena strigosa Schreb) e azevém (Lolium multiflorum Lam.) como espécies fitorremediadoras de áreas contaminadas por As. Amostras de Latossolo Vermelho-Amarelo foram incubadas por 15 dias com diferentes doses de As: 0; 50; 100; e 200 mg dm-3. Em seguida, realizaram-se a semeadura das quatro espécies e as respectivas adubações. Aos 65 dias após a semeadura, as plantas foram avaliadas quanto à altura, à matéria seca da parte aérea e raízes. Determinaram-se os teores de As nas folhas jovens, intermediárias e basais, no caule e nas raízes, bem como o conteúdo e o índice de translocação (IT) de As. Por meio de análises de regressão, foram estimados os teores críticos (TC) de As disponíveis no solo, que proporcionaram redução de 50 % da matéria seca. As espécies estudadas apresentaram comportamento diferenciado quanto à tolerância ao As, com destaque para azevém, amendoim e estilosante, que não apresentaram lesões foliares decorrentes de fitotoxidez por esse elemento. Os TC para as plantas de aveia e azevém foram significativamente superiores aos observados para as demais espécies, caracterizando-as como espécies tolerantes ao As. As plantas de amendoim e estilosante apresentaram maior capacidade de absorção e maior IT de As para a parte aérea. As plantas de amendoim apresentaram maiores teores nas folhas basais e raízes, mostrando potencial para serem utilizadas em programas de fitorremediação. As plantas de azevém, amendoim e estilosante podem ser utilizadas na fitoestabilização e, ou, na revegetação de áreas contaminadas por As, uma vez que apresentaram tolerância a esse elemento. Por se tratar de espécies forrageiras, quando utilizadas para esses fins, cuidados especiais são necessários, como o isolamento da área, para evitar a entrada do elemento na cadeia trófica

Behavior of Eucalyptus grandis and E. cloeziana seedlings grown in arsenic-contaminated soil

Arsenic has been considered the most poisonous inorganic soil pollutant to living creatures. For this reason, the interest in phytoremediation species has been increasing in the last years. Particularly for the State of Minas Gerais, where areas of former mining activities are prone to the occurrence of acid drainage, the demand is great for suitable species to be used in the revegetation and "cleaning" of As-polluted areas. This study was carried out to evaluate the potential of seedlings of Eucalyptus grandis (Hill) Maiden and E. cloeziana F. Muell, for phytoremediation of As-polluted soils. Soil samples were incubated for a period of 15 days with different As (Na2HAsO4) doses (0, 50, 100, 200, and 400 mg dm-3). After 30 days of exposure the basal leaves of E. cloeziana plants exhibited purple spots with interveinal chlorosis, followed by necrosis and death of the apical bud at the 400 mg dm-3 dose. Increasing As doses in the soil reduced root and shoot dry matter, plant height and diameter in both species, although the reduction was more pronounced in E. cloeziana plants. In both species, As concentrations were highest in the root system; the highest root concentration was found in E. cloeziana plants (305.7 mg kg-1) resulting from a dose of 400 mg dm-3. The highest As accumulation was observed in E. grandis plants, which was confirmed as a species with potential for As phytoextraction, tending to accumulate As in the root system and stem

Growth of seedlings of pigeon pea (Cajanus cajan (l.) millsp), wand riverhemp (Sesbania virgata (cav.) pers.), and lead tree (Leucaena leucocephala (lam.) de wit) in an arsenic-contaminated soil

Phytoremediation strategies utilize plants to decontaminate or immobilize soil pollutants. Among soil pollutants, metalloid As is considered a primary concern as a toxic element to organisms. Arsenic concentrations in the soil result from anthropogenic activities such as: the use of pesticides (herbicides and fungicides); some fertilizers; Au, Pb, Cu and Ni mining; Fe and steel production; coal combustion; and as a bi-product during natural gas extraction. This study evaluated the potential of pigeon pea (Cajanus cajan), wand riverhemp (Sesbania virgata), and lead tree (Leucaena leucocephala) as phytoremediators of soils polluted by As. Soil samples were placed in plastic pots, incubated with different As doses (0; 50; 100 and 200 mg dm-3) and then sown with seeds of the three species. Thirty (pigeon pea) and 90 days after sowing, the plants were evaluated for height, collar diameter and dry matter of young, intermediate and basal leaves, stems and roots. Arsenic concentration was determined in different aged leaves, stems and roots to establish the translocation index (TI) between the plant root system and aerial plant components and the bioconcentration factors (BF). The evaluated species showed distinct characteristics regarding As tolerance, since the lead tree and wand riverhemp were significantly more tolerant than pigeon pea. The high As levels found in wand riverhemp roots suggest the existence of an efficient accumulation and compartmentalization mechanism in order to reduce As translocation to shoot tissues. Pigeon pea is a sensitive species and could serve as a potential bioindicator plant, whereas the other two species have potential for phytoremediation programs in As polluted areas. However, further studies are needed with longer exposure times in actual field conditions to reach definite conclusions on relative phytoremediation potentials

Growth of seedlings of pigeon pea (Cajanus cajan (l.) millsp), wand riverhemp (Sesbania virgata (cav.) pers.), and lead tree (Leucaena leucocephala (lam.) de wit) in an arsenic-contaminated soil

Phytoremediation strategies utilize plants to decontaminate or immobilize soil pollutants. Among soil pollutants, metalloid As is considered a primary concern as a toxic element to organisms. Arsenic concentrations in the soil result from anthropogenic activities such as: the use of pesticides (herbicides and fungicides); some fertilizers; Au, Pb, Cu and Ni mining; Fe and steel production; coal combustion; and as a bi-product during natural gas extraction. This study evaluated the potential of pigeon pea (Cajanus cajan), wand riverhemp (Sesbania virgata), and lead tree (Leucaena leucocephala) as phytoremediators of soils polluted by As. Soil samples were placed in plastic pots, incubated with different As doses (0; 50; 100 and 200 mg dm-3) and then sown with seeds of the three species. Thirty (pigeon pea) and 90 days after sowing, the plants were evaluated for height, collar diameter and dry matter of young, intermediate and basal leaves, stems and roots. Arsenic concentration was determined in different aged leaves, stems and roots to establish the translocation index (TI) between the plant root system and aerial plant components and the bioconcentration factors (BF). The evaluated species showed distinct characteristics regarding As tolerance, since the lead tree and wand riverhemp were significantly more tolerant than pigeon pea. The high As levels found in wand riverhemp roots suggest the existence of an efficient accumulation and compartmentalization mechanism in order to reduce As translocation to shoot tissues. Pigeon pea is a sensitive species and could serve as a potential bioindicator plant, whereas the other two species have potential for phytoremediation programs in As polluted areas. However, further studies are needed with longer exposure times in actual field conditions to reach definite conclusions on relative phytoremediation potentials.A fitorremediação é uma estratégia que utiliza plantas para descontaminar ou imobilizar poluentes do solo. Entre os poluentes do solo, o As é considerado o principal elemento tóxico aos organismos vivos. A presença de As no solo pode ser decorrente de atividades antrópicas, como: uso de pesticidas (herbicidas e fungicidas); alguns fertilizantes; extração de Au, Pb, Cu e Ni; produção de Fe e aço; combustão de carvão; e coprodução durante a extração de gás natural. Este trabalho avaliou o potencial de feijão-guandu (Cajanus cajan), sesbania (Sesbania virgata) e leucena (Leucaena leucocephala) como fitorremediadoras de solos contaminados por As. Amostras de solo foram colocadas em potes de plástico, incubadas com diferentes doses de As (0, 50, 100 e 200 mg dm-3) e semeados com sementes das três espécies. Aos 30 (feijão-guandu) e aos 90 dias após a semeadura, as plantas foram avaliadas quanto a altura, diâmetro de colo e matéria seca de folhas jovens, intermediárias e basais, ramos e raízes. A concentração de As foi determinada nas diferentes folhas, ramos e raízes, a fim de estabelecer o índice de translocação (TI) entre o sistema radicular e a parte aere das plantas e o fator de bioconcentração (BF). As espécies avaliadas apresentaram comportamento distinto em relação à tolerância ao As, uma vez que a sesbania e a leucena foram significativamente mais tolerantes que o feijão guandu. A elevada concentração de As encontrada nas raízes de sesbania sugere a existência de um eficiente mecanismo de acumulação e compartimentalização, no sentido de reduzir a translocação para os tecidos da parte aérea. O feijão-guandu é uma espécie sensível ao As, podendo ser utilizado como planta indicadora, enquanto as outras duas espécies apresentam potencial para serem utilizadas em programas de fitorremediação de áreas contaminadas por As. Entretanto, estudos futuros em condições de campo e de longa duração são necessários para a obtenção de conclusões definitivas em relação ao potencial de fitorremediação dessas espécies

Diversity of Mosquitoes (Diptera: Culicidae) in the Caatinga Biome, Brazil, from the Widespread to the Endemic

Mosquito fauna in the northeast semiarid region of Brazil, Caatinga biome, are poorly known. Studies on the diversity are scarce and the few surveys available focus on local fauna. In order to understand the ecological pattern of mosquito’s distribution, information available from studies from 2008 to 2015 were gathered. A partitioning framework of the beta diversity, the turnover (βJTU) and nestedness (βJNE) components were used to determine dissimilarity among communities. Eighty-two morphospecies were recorded and 47 of the species were not shared between the areas. The most representative genera were Aedes, Anopheles, Psorophora, Haemagogus, Coquillettidia, and Mansonia, which all include species of medical interest. The communities had high rates of variation, and the mechanism of turnover accounted for the observed diversity pattern. Despite differences in collection methods, the observed dissimilarity may be related to the broad environmental heterogeneity of the biome, the intrinsic relationships of the species with their habitats, and the environmental degradation caused by different types of anthropogenic interference. Considering the mosquito species richness and endemicity, the hypothesis that the Caatinga harbor poor biodiversity is rejected. The spatial variation observed is of particular importance and should be taken into account for the knowledge of Caatinga biodiversity