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1.
Braz. j. microbiol ; 49(4): 742-748, Oct.-Dec. 2018. graf
Article in English | LILACS | ID: biblio-974296

ABSTRACT

ABSTRACT We examined microbial communities from enriched fine and retorted shale particles using sequencing of V4 variable region of 16S rRNA. High number of microbial genera was found in both enriched shale by-products that were dominate by Actinobacteria, Firmicutes and Proteobacteria, showing differences due to microbial colonization after the pyrolysis process.


Subject(s)
Bacteria/isolation & purification , Waste Products/analysis , Geologic Sediments/microbiology , Microbiota , Phylogeny , Bacteria/classification , Bacteria/genetics , Brazil , DNA, Bacterial/genetics , RNA, Ribosomal, 16S/genetics , Geologic Sediments/chemistry , Biodiversity
2.
Braz. j. microbiol ; 48(1): 71-78, Jan.-Mar. 2017. tab, graf
Article in English | LILACS | ID: biblio-839359

ABSTRACT

Abstract In this study, determination of heavy metal parameters and microbiological characterization of marine sediments obtained from two heavily polluted sites and one low-grade contaminated reference station at Jiaozhou Bay in China were carried out. The microbial communities found in the sampled marine sediments were studied using PCR-DGGE (denaturing gradient gel electrophoresis) fingerprinting profiles in combination with multivariate analysis. Clustering analysis of DGGE and matrix of heavy metals displayed similar occurrence patterns. On this basis, 17 samples were classified into two clusters depending on the presence or absence of the high level contamination. Moreover, the cluster of highly contaminated samples was further classified into two sub-groups based on the stations of their origin. These results showed that the composition of the bacterial community is strongly influenced by heavy metal variables present in the sediments found in the Jiaozhou Bay. This study also suggested that metagenomic techniques such as PCR-DGGE fingerprinting in combination with multivariate analysis is an efficient method to examine the effect of metal contamination on the bacterial community structure.


Subject(s)
Bacteria , Geologic Sediments/microbiology , Geologic Sediments/chemistry , Metals, Heavy , Biodiversity , Environmental Microbiology , Environmental Pollutants , Environmental Pollution , Bacteria/classification , Cluster Analysis , China , Bays , Environment
3.
Rev. biol. trop ; 64(3): 1185-1200, jul.-sep. 2016. tab, ilus
Article in English | LILACS | ID: biblio-958205

ABSTRACT

Abstract:Coral reef ecosystems are under stress of different origins, from factors including sedimentation, fragmentation, overfishing, and tourism, depending on their geographical location, depth, and proximity to recreation areas. In this study of Juluapan Lagoon, we examined the relationship between various water-quality attributes and the status indicators of the coral community at La Boquita reef. During 2011 (12 months of sampling), six monitoring stations in the Juluapan lagoon were established in order to observe the gradient of the distribution of the physicochemical parameters: three stations on the upper part, or BI, (S4 to S6) and three more in the lower part, or BII, (S1 to S3). A control station (CS) was located in the coral reef close to the lagoon channel, and where dissolved inorganic nutrients and cellular carbon content were determined. Additionally, we considered the monitoring of three of the eight largest coral structures/headlands of this community: the first was the station closest to the channel communicating with Juluapan lagoon (C1), the second was in the intermediate region with respect to that lagoon (C2), and the third was farthest from the channel (C3). Three line intercept transects (LIT) 30 m in length and perpendicular to the coast provenance were established in each station, and the parameters indicative of the status of corals were evaluated in an area of 60 m2 on each transect (180 m2 by the station). Turbidity, evidence of fishing, signs of settling, algal coverage, abundance of fish, rate of sediment, and coral health records (as for CoralWach chart) were determined in situ and from digital photographs and videos. Considering various community status indicators used in the reef area, we could recognize a state of general deterioration, which was reflected in the loss of 17% of coral coverage. The main anthropogenic disturbances in adjacent areas to La Boquita reef included wastewater discharges into the lagoon, tourist developments in the coastal zone, deforestation and erosion resulting from inappropriate development, and the runoff of nutrients from agricultural lands nearby the lagoon. All these significantly contributed to the nutrient-enriched waters of the lagoon, especially in summer, with negative effects on the coral community. Continued exposure to these factors, coupled with the lack of control over other anthropogenic components, has promoted the maintenance of a chronic stress state in the studied coral community. Our findings highlight the need for the development of appropriate coastal management and conservation policies for the coral reefs of the Mexican Pacific Coast. Rev. Biol. Trop. 64 (3): 1185-1200. Epub 2016 September 01.


ResumenDependiendo de la ubicación geográfica, la profundidad, y la proximidad a zonas de recreo, algunos arrecifes de coral están bajo estrés por factores que incluyen la sedimentación, la fragmentación, la sobrepesca y el turismo. En la presente investigación, se estudian los diferentes atributos de calidad de agua de la Laguna Juluapan e indicadores del estatus de la comunidad coralina La Boquita. Durante 2011 (12 meses de muestreo), seis estaciones de monitoreo fueron establecidas dentro de la laguna de Juluapan, a fin de observar el gradiente de distribución de los parámetros fisicoquímicos: tres estaciones en la parte interna ó B1, (S4 a S6), y tres en la parte más externa, ó B2 (S1 a S3); una estación control (CS) fue ubicada en la zona coralina cercana a la comunicación con la Laguna de Juluapan, fueron determinados nutrientes inorgánicos disueltos y contenido de carbono celular. Adicionalmente se realizó el monitoreo de tres de los ocho cabezales coralinos que conforman esta comunidad. El primero de ellos fue localizado en la cercanía de la intercomunicación con la Laguna Juluapan (C1), el segundo en la región intermedia respecto a la proximidad de dicho cuerpo lagunar (C2), y el tercero totalmente alejado respeto a la intercomunicación (C3). En cada estación fueron colocadas, tres líneas de transectos de intersección (LIT) de 30 m de longitud de forma perpendicular al perfil de la costa, a partir de ello, fueron evaluados diversos parámetros de la condición coralina, cubriendo un área de 60 m2 en cada transecto (180 m2 por estación). En cada área de transecto fue evaluada la turbidez, evidencias de daños por pesca, daños por sedimentación, cobertura de algas, abundancia de peces, tasa de sedimentación, además de obtenerse registros de la salud coralina usando como indicador la tarjeta CoralWatch in situ, a partir de tomas fotográficas y videos. Considerando los diferentes indicadores del estatus de la comunidad coralina estudiada, nosotros pudimos reconocer un estado general de deterioro, reflejado en la pérdida del 17% de la cobertura de coral. Las principales alteraciones antropogénicas en las zonas adyacentes al arrecife La Boquita corresponde a descargas de aguas residuales en la laguna, desarrollos turísticos en la zona costera, la deforestación y efecto erosivo asociado al desarrollo urbano inadecuado, así como el escurrimiento de nutrientes de tierras agrícolas alrededor de la laguna. Estos factores contribuyen de manera significativa al enriquecimiento de nutrientes a la laguna, sobre todo en verano, con efectos negativos sobre la comunidad de coral. La exposición continua a estos factores, junto con la falta de control sobre otros componentes antropogénicos, promueve la existencia de un estado de estrés crónico en la comunidad coralina estudiada. Nuestros resultados destacan la necesidad de implementar políticas apropiadas de conservación para los arrecifes coralinos de la costa del Pacífico mexicano.


Subject(s)
Water Pollution, Chemical/adverse effects , Water Quality , Coral Reefs , Phytoplankton , Seasons , Seawater/chemistry , Temperature , Time Factors , Pacific Ocean , Analysis of Variance , Bays , Conservation of Natural Resources , Geologic Sediments/chemistry , Salinity , Mexico
4.
Braz. j. biol ; 74(4): 877-885, 11/2014. tab, graf
Article in English | LILACS | ID: lil-732315

ABSTRACT

This study aims to determine concentrations and characterize trace metals distribution in an affluent of Furnas reservoir, Alfenas-MG. Water and sediment samples were taken monthly, 2010/10-2011/07 in five sites of Córrego do Pântano for subsequent determination of Pb, Cd and Zn levels by chemical analysis. The stream studied is in disagreement with Brazilian legislation for Class II water bodies (CONAMA 357). The highlights are the unsuitable concentrations of Pb for human consumption, according to Ministry of Health 2914 decree, providing risk for population.


Este trabalho objetiva determinar as concentrações e caracterizar a distribuição de metais traço em um afluente do Reservatório de Furnas, em Alfenas-MG. Foram coletadas amostras de água e sedimento de Outubro de 2010 a Julho de 2011 em cinco pontos do Córrego do Pântano para posterior determinação dos níveis de Cd, Pb e Zn através da análise química. O córrego estudado encontra-se em desacordo com a legislação brasileira para corpos de água Classe II (CONAMA 357). Destacam-se as concentrações de Pb inadequadas para consumo humano, conforme a portaria n° 2914 do Ministério da Saúde, oferecendo risco à população.


Subject(s)
Environmental Monitoring/methods , Geologic Sediments/chemistry , Metals, Heavy/analysis , Rivers/chemistry , Water Pollutants, Chemical/analysis , Brazil , Water Supply/standards
5.
Braz. j. biol ; 74(4): 769-778, 11/2014. tab, graf
Article in English | LILACS | ID: lil-732325

ABSTRACT

Most rivers are used as a source to supply entire cities; the quality of water is directly related to the quality of tributaries. Unfortunately men have neglected the importance of streams, which receive domestic and industrial effluents and transport nutrients and pesticides from rural areas. Given the complexity of the mixtures discharged into these water bodies, this study aimed to evaluate the quality of water and sediment of ten tributaries of Pirapó River, in Maringá, Paraná State, Brazil. To this end, the free-floating macrophyte Landoltia punctata (G. Meyer) Les & D.J.Crawford was used as test organism in microcosm, and the toxicity of water and sediment samples was evaluated by the relative growth rate, dry/fresh biomass ratio, and genotoxic effects (comet assay). Samples of water and sediment of each stream were arranged in microcosms with L. punctata. Seven days later, plants were collected for analysis. Nutrient levels were higher than the reference location, indicating eutrophication, but the results indicated a toxic effect for only three streams, and a genotoxic effect for all streams.


Muitos rios são utilizados como fonte de abastecimento de cidades inteiras e a qualidade de suas águas está relacionada diretamente à qualidade de seus afluentes. Infelizmente córregos têm sua importância negligenciada pelo homem sendo alvo de despejos domésticos e industriais e também do carreamento de nutrientes e pesticidas das áreas rurais. Diante da complexidade das misturas que atingem estes corpos d'água, o presente estudo teve por objetivo avaliar a qualidade da água e do sedimento de dez afluentes do rio Pirapó no município de Maringá, Estado do Paraná. Utilizou-se a macrófita aquática flutuante Landoltia punctata (G. Meyer) Les & D.J.Crawford como organismo teste em microcosmos, sendo que a toxicidade das amostras de água e sedimento foi avaliada pela taxa de crescimento relativo, pelo índice de biomassa seca por fresca, e pelos efeitos genotóxicos (ensaio de cometa). Amostras de água e sedimento de cada córrego foram dispostos em microcosmos com L. punctata. Após 7 dias as plantas foram coletadas para as análises. Os níveis de nutrientes foram maiores que o do local de referência indicando eutrofização; porém, os resultados indicaram efeito tóxico em apenas três dos córregos e genotóxico em todos os córregos.


Subject(s)
Environmental Monitoring/methods , Geologic Sediments/chemistry , Plants , Rivers/chemistry , Water Pollutants, Chemical/toxicity , Biomass , Brazil , Eutrophication , Plants/drug effects , Plants/genetics , Toxicity Tests
6.
Braz. j. biol ; 74(3,supl.1): S113-S119, 8/2014. tab, graf
Article in English | LILACS | ID: lil-732265

ABSTRACT

It is well accepted in the literature that lakes are generally net heterotrophic and supersaturated with CO2 because they receive allochthonous carbon inputs. However, autotrophy and CO2 undersaturation may happen for at least part of the time, especially in productive lakes. Since diurnal scale is particularly important to tropical lakes dynamics, we evaluated diurnal changes in pCO2 and CO2 flux across the air-water interface in a tropical productive lake in southeastern Brazil (Lake Carioca) over two consecutive days. Both pCO2 and CO2 flux were significantly different between day (9:00 to 17:00) and night (21:00 to 5:00) confirming the importance of this scale for CO2 dynamics in tropical lakes. Net heterotrophy and CO2 outgassing from the lake were registered only at night, while significant CO2 emission did not happen during the day. Dissolved oxygen concentration and temperature trends over the diurnal cycle indicated the dependence of CO2 dynamics on lake metabolism (respiration and photosynthesis). This study indicates the importance of considering the diurnal scale when examining CO2 emissions from tropical lakes.


É amplamente aceito na literatura que lagos são em geral heterotróficos e supersaturados com CO2 já que recebem carbono alóctone. Porém, autotrofia e insaturação de CO2 podem ocorrer em pelo menos parte do tempo, especialmente em lagos produtivos. Como a escala diurna é particularmente importante para a dinâmica de lagos tropicais, variações diurnas na pCO2 e no fluxo de CO2 através da interface ar-água foram avaliadas num lago tropical produtivo do sudeste do Brasil (Lagoa Carioca) durante dois dias consecutivos. Tanto a pCO2 quanto o fluxo de CO2 foram significativamente diferentes entre o dia (9:00 às 17:00) e a noite (21:00 às 5:00), confirmando a influência desta escala na dinâmica do CO2 na Lagoa Carioca. Foram registradas heterotrofia e emissão de CO2 pela lagoa apenas durante a noite, enquanto durante o dia não houve emissão significativa. Variações na concentração de oxigênio dissolvido e na temperatura ao longo do dia indicaram a dependência da dinâmica do CO2 no metabolismo (respiração e fotossíntese) deste lago. Este estudo indica a importância de se considerar a escala diurna na avaliação da emissão de CO2 por lagos tropicais.


Subject(s)
Carbon Dioxide/analysis , Geologic Sediments/chemistry , Lakes/chemistry , Brazil , Carbon Dioxide/metabolism , Seasons
7.
Braz. j. biol ; 73(3): 549-558, ago. 2013. tab, graf
Article in English | LILACS | ID: lil-689854

ABSTRACT

The damming of a river causes dangerous consequences on structure of the environment downstream of the dam, modifying the sediment composition, which impose major adjustments in longitudinal distribution of benthic community. The construction of Engenheiro Sérgio Motta Dam in the Upper Paraná River has caused impacts on the aquatic communities, which are not yet fully known. This work aimed to provide more information about the effects of this impoundment on the structure of Chironomidae larvae assemblage. The analysis of data of physical and chemical variables in relation to biological data of 8 longitudinal sections in the Upper Paraná River showed that composition of Chironomidae larvae of stations near Engenheiro Sérgio Motta Dam differed of the other stations (farther of the Dam). The predominance of coarse sediments at stations upstream and finer sediments further downstream affected the choice of habitat by different morphotypes of Chironomidae and it caused a change in the structure of this assemblage in the longitudinal stretch.


O barramento de um rio pode causar graves consequências sobre a natureza do ambiente, abaixo da barragem, modificando a composição do sedimento, as quais impõem importantes ajustes da distribuição longitudinal das comunidades bentônicas. A construção da Usina Hidrelétrica Engenheiro Sérgio Motta no alto rio Paraná, tem causado impactos em várias comunidades aquáticas, que ainda não são totalmente conhecidos. Este trabalho objetivou fornecer mais informações sobre os efeitos desse represamento na assembleia de Chironomidae. A análise das variáveis físicas e químicas em relação aos dados biológicos de oito transectos longitudinais no alto rio Paraná revelou que a composição das larvas de Chironomidae das estações mais próximas à barragem da Usina Engenheiro Sérgio Motta diferiu das demais (estações mais distantes). A predominância de sedimentos mais grosseiros nas estações a montante e sedimentos mais finos mais a jusante afetou a escolha de habitat pelos diferentes morfotipos de Chironomidae, que levou a alteração na estrutura desta assembleia ao longo do trecho amostrado.


Subject(s)
Animals , Biodiversity , Chironomidae/classification , Environmental Monitoring , Geologic Sediments/chemistry , Rivers/chemistry , Brazil , Larva , Population Density , Population Dynamics
8.
Braz. j. biol ; 73(1): 115-123, Feb. 2013. ilus, tab
Article in English | LILACS | ID: lil-671371

ABSTRACT

Measurements of nutrient and suspended matter concentrations and loads entering and leaving the Castanhão reservoir during the rainy season were carried out to assess the influence of this large reservoir on land-sea fluvial transport in the ephemeral Jaguaribe river basin. Spatial variation indicated statistically significant attenuation of concentrations only for total phosphorous and suspended matter across the reservoir. Strong retention of nutrients and suspended matter loads by the reservoir was observed with average trapping efficiency of 89% for dissolved silicon, 98% of soluble reactive phosphorus, 71% for ammonium, 87% for total nitrogen, 98% for total phosphorus and 97% for suspended matter compared to the reservoir inflow. The dam operational procedure defined by the ephemeral conditions of the river reduced water releases compared to reservoir inflow and induced strong retention of nutrient and suspended matter loads within the reservoir when fluvial transfer occurs in this semiarid watershed.


Medidas de concentrações e fluxos de nutrientes e material particulado em suspensão de entrada e saída do Açude Castanhão foram efetuadas para determinar a influência de um grande reservatório no transporte fluvial entre o continente e o oceano na bacia hidrográfica intermitente do Rio Jaguaribe. A variação espacial indicou uma atenuação estatisticamente significativa ao longo do reservatório somente para as concentrações de fósforo total e material particulado em suspensão. Os resultados indicam uma forte retenção de nutrientes e do material particulado em suspensão com eficiências de retenção de 89% para sílica dissolvida, 98% para fósforo solúvel reativo, 71% para amônia, 87% para nitrogênio total, 98% para fósforo total e 97% para o material particulado em suspensão em relação aos fluxos de entrada no reservatório. A rotina de operação da barragem definida pela condição intermitente do Rio Jaguaribe reduz a descarga de água comparada com a entrada no reservatório e induz forte retenção do fluxo fluvial de nutrientes e material particulado em suspensão pelo reservatório.


Subject(s)
Environmental Monitoring , Geologic Sediments/chemistry , Rivers/chemistry , Water Movements , Brazil , Nitrogen/analysis , Phosphorus/analysis , Quaternary Ammonium Compounds/analysis , Rain , Seasons , Silicon/analysis
9.
Rev. biol. trop ; 60(3): 1289-1301, Sept. 2012. mapas, tab
Article in English | LILACS | ID: lil-659588

ABSTRACT

Cross River serves as a major source of drinking water, transportation, agricultural activities and fishing in Cross River State, Nigeria. Since there is no formal control of effluents discharged into the river, it is important to monitor the levels of metals contaminants in it, thus assessing its suitability for domestic and agricultural use. In order to determine this, three sampling stations designated as Ikom (Station I), Obubra Ogada (Station II) and Calabar (Station III) were randomly selected to study. For this, ten samples of the freshwater Silver Catfish (Chryshchythys nigrogitatus) (29.4-39.5cm SL, 310-510g), sediment and water were collected from each sampling Station from June 2009-June 2010. The heavy metals profiles of Zn, Cu, Fe, Co, Pb, Cd and Cr, in water, sediments and fish muscle were analyzed by atomic absorption spectrophotometry (AAS). In fish, the heavy metals concentration was found to be Cu>Fe>Zn>Cu>Pb>Cd>Co; the highest mean concentration of Copper (0.297±0.022 μg/g), Cadmium (0.011±0.007μg/g), Iron (0.371±0.489μg/g), Lead (0.008±0.008μg/g), were determined for the fish. In water, the order was found to be Fe>Pb>Zn>Cu>Cr>Cd>Co; the highest mean concentration of Iron (0.009±0.00μg/g), Copper (0.015±0.01 μg/g), Lead (0.0002±0.00μg/g) Cadmium (0.0006±0.001μg/g), Zinc (0.0036±0.003μg/g), were observed in the surface water, respectively. The highest mean concentration of Copper (0.037±0.03μg/g), Iron (0.053±0.04μg/g), Lead (0.0002±0.00μg/g), Cobalt (0.0002±0.00μg/g), Cadmium (0.0006±0.001μg/g) and Zinc (.009±0.0015μg/g) was observed in the bottom water. In sediments, the concentration order found was Zn>Fe>Cu>Pb>Co>Cd; the highest mean concentration of 0.057±0.04μg/g, 0.043±0.03μg/g, 0.0006±0.00μg/g, 0.0002±0.00μg/g, 0.0009±0.00μg/g, 0.099±0.00404μg/g in Iron, Copper, Lead, Cobalt, Cadmium and Zinc were observed in the sediment, respectively; Chromium was not detected in the sediment for the whole sampling area. Most of the heavy metals were below the maximum allowable levels set by the WHO, FEPA and USEPA, except Zinc which mean concentration of 0.099±0.00404μg/g was above the recommended limit of 0.0766μg/g of USEPA in the sediment at Ikom. This implies that the waste assimilation capacity of the river is high, a phenomenon that could be ascribed to dilution, sedimentation and continuous water exchange. This is an indication that an urban and industrial waste discharged into the Cross River has a significant effect on the ecological balance of the river. Thus fish species from the Cross River harvested are safe for human consumption.


Cross River funciona como una fuente importante de agua potable, transporte, actividades agrícolas y pesqueras en el Estado Cross River, Nigeria. Dado que no existe un control formal de los efluentes vertidos en el río, es importante monitorear los niveles de metales contaminantes en el mismo, por lo tanto la evaluación de su idoneidad para el uso doméstico y agrícola. Para la determinación de lo anterior, tres estaciones de muestreo designadas como Ikom (Estación I), Obubra Ogada (Estación II) y Calabar (Estación III) fueron seleccionadas al azar para el estudio. Se tomaron diez muestras de “Bagre de agua dulce de plata” (Chryshchythys nigrogitatus) de 29.4-39.5cm LE (longitud estándar) y 310-510g de peso, sedimentos y agua fueron recolectadas en cada estación de muestreo de junio 2009 a junio 2010. Los perfiles de metales pesados de Zn, Cu, Fe, Co, Pb, Cd y Cr, en agua, sedimentos y músculos de peces fueron analizados por espectrofotometría de absorción atómica (AAS). En los peces, la concentración de metales pesados que se determinó fue Cu>Fe>Zn>Cu>Pb>Cd>Co, para los peces se determinó una mayor concentración media de cobre (0.297±0.022g/g), cadmio (0.011±0.007μg/g), hierro (0.371±0.489μg/g) y plomo (0.008±0.008μg/g). En el agua, el orden se determinó como sigue: Fe>Pb>Zn>Cu>Cr>Cd>Co, con una mayor concentración promedio de hierro (0.009±0.00μg/g), cobre (0.015±0.01g/g), plomo (0.0002±0.00μg/g), cadmio (0.0006±0.001μg/g) y zinc (0.0036±0.003μg/g), se observaron en la superficie del agua, respectivamente. La mayor concentración promedio de cobre (0.037±0.03μg/g), hierro (0.053±0.04μg/g), plomo (0.0002±0.00μg/g), cobalto (0.0002±0.00μg/g), cadmio (0.0006±0.001g/g) y zinc (0.009±0.0015μg/g) se observó en el agua del fondo. En los sedimentos, el orden de concentración fue: Zn>Fe>Cu>Pb>Co>Cd, la mayor concentración media fue de 0.057±0.04μg/g, 0.043±0.03μg/g, 0.0006±0.00μg/g, 0.0002±0.00μg/g, 0.0009±0.00μg/g y 0.099±0.00404μg/g para hierro, cobre, plomo, cobalto, cadmio y zinc, respectivamente, no se detectó cromo. La mayoría de los metales pesados por debajo de los niveles máximos permisibles establecidos por la OMS, FEPA y USEPA, con excepción de zinc cuya concentración media fue de 0.099±0.00404μg/g estuvo por encima del límite recomendado de 0.0766μg/g de EPA en el sedimento de la Estación I (Ikom). Esto implica que la capacidad de asimilación de residuos del río es alta, un fenómeno que podría atribuirse a la dilución, la sedimentación y el intercambio continuo de agua. Lo cual es una indicación de que efluentes vertidos en el Cross River por zonas urbanas e industriales tienen un efecto significativo en el equilibrio ecológico del río. Así, las especies de peces del Río Cross son seguras para el consumo humano.


Subject(s)
Animals , Catfishes/metabolism , Environmental Monitoring/methods , Geologic Sediments/chemistry , Metals, Heavy/analysis , Rivers/chemistry , Water Pollutants, Chemical/analysis , Catfishes/classification , Nigeria , Spectrophotometry, Atomic
10.
Braz. j. biol ; 72(3): 429-436, Aug. 2012. ilus, tab
Article in English | LILACS | ID: lil-649329

ABSTRACT

The aim of this research was to evaluate the effect of sediment composition on methane (CH4) dynamics in sediments of different areas in the transition zone between a mangrove and the sea. This research was conducted in a mangrove at Coroa Grande, on the southern coast of Rio de Janeiro. Samples were collected at three stations: (1) region colonised by Rhizophora mangle L. on the edge of the mangrove, (2) region colonised by seagrasses and (3) infra-littoral region without vegetation. Samples were collected from the surface layer of the sediment to determine the concentrations of nutrients (C, N and P) and CH4 concentration and production. We observed that concentrations of CH4 and carbon (C) were significantly higher (p < 0.05) in station 1 than station 3. The molar ratios (C:N, C:P and N:P) suggest that the origin of the substrate is mainly autochthonous. Methanogenesis was initially low, possibly due to competition between methanogens and sulfate reducers, and increased significantly (p < 0.05) on the twenty-sixth day in the sediment of station 1, probably due to higher organic matter (OM) availability in this region. Results indicate that methanogenic activity observed herein is not regulated by the amount or quality of OM, but by other factors. The concentration of CH4 in the sea-land ecotone at Mangrove Coroa Grande is a function of available OM suggesting a possible inhibition of methanotrophy by intense oxygen consumption in the soil surface covered by detritus of Rhizophora mangle vegetation.


O objetivo desta pesquisa foi avaliar a dinâmica do metano (CH4) no sedimento em diferentes áreas na região de transição entre a borda do manguezal e o mar, em função da composição do sedimento. A pesquisa foi realizada no Manguezal de Coroa Grande, no litoral sul do Estado do Rio de janeiro. Foram coletadas amostras em três estações: (1) região colonizada por Rhizophora mangle L. na borda do mangue, (2) região colonizada por macrófitas, e (3) região sem vegetação, permanentemente inundada pelo mar. Foram coletadas amostras da fração superficial do sedimento para determinação da concentração de nutrientes (C, N e P), e da concentração e da produção de CH4. Foi observado que as concentrações de CH4 e carbono (C) foram significativamente maiores (p < 0,05) na estação 1, em relação à estação 3. Com relação às razões molares (C:N, C:P e N:P), estas indicam que a origem da composição do substrato é principalmente autóctone. Quanto à metanogênese, foram observados, inicialmente, baixos valores de CH4 produzido, indicando provável competição entre metanogênicos e sulfatorredutores. Seguiu-se, então, um significativo aumento (p < 0,05) da metanogênese no 26º dia, no sedimento da estação 1, provavelmente em função da maior disponibilidade de matéria orgânica (MO) nessa região. Os resultados mostram que a atividade metanogênica observada pela presente pesquisa não é regulada pela quantidade e a qualidade da MO e sim por outros fatores. A concentração de CH4 no ecótono mar-terra no manguezal de Coroa Grande, ocorre em função da MO disponível, sugerindo possível inibição da metanotrofia, em razão de intenso consumo de oxigênio na superfície do solo coberto pelo detrito da vegetação de Rhizophora mangle.


Subject(s)
Environmental Monitoring , Geologic Sediments/chemistry , Methane/biosynthesis , Rhizophoraceae , Brazil , Carbon/analysis , Methane/analysis , Nitrogen/analysis , Phosphorus/analysis , Seasons
11.
Iranian Journal of Public Health. 2012; 41 (3): 26-35
in English | IMEMR | ID: emr-118133

ABSTRACT

Heavy metal pollution in the sediment of the Yellow River draws wide attention in the recent years. The Yellow River wetland nature reserve of Zhengzhou is one of the major wetlands of the river and located at the beginning of the lower reach. In this article, we aimed to investigate the degree and the sources of the metal pollution in the reserve. Metals as Cu, Pb, Cr, Cd and Mn in the sediment were monitored using flame atomic absorption spectrometry. The index of geo-accumulation [I[geo]] and the modified degree of contamination [mC[d]] were developed to evaluate individual metal pollution and overall enrichment impact of the elements. Compared with sediment quality guidelines, the effect of Cr and Pb are more serious than others. I [geo] values show Pb pollution are moderate at the Xinzhai, Langchenggang and Nansutan sites, and mC[d] analysis indicate the whole contamination at the Wantan, Langchenggang and Nansutan sites was low. Principal component analysis indicated that the first factor was Cu, Mn and Cd, mainly from soil erosion and the irrational use of phosphate fertilizers; the second Pb from fossil fuel burning; and the third Cr from weathering process. We conclude that Pb contamination is serious in the reserve, and the main sources of the metal are crude oil consumption and coal combustion of the brick kilns around. We also draw a conclusion that it is vital to evaluate contamination degree with both individual elements and overall average


Subject(s)
Metals, Heavy/analysis , Geologic Sediments/chemistry , Rivers
12.
International Journal of Environmental Research. 2012; 6 (3): 613-626
in English | IMEMR | ID: emr-144231

ABSTRACT

Eight selected heavy metals [Cu, Zn, Pb, Cd, Cr, Mn, Fe and Al] in surface and sub-surface sediments in the northern coast of Sfax [Tunisia] were studied in order to assess the sediment quality and to highlight the anthropogenic contributions to heavy metal distributions in the two study sediment levels. Multiple chemometric approaches based on Geographic Information System [GIS], Enrichment factors [EFs], geoaccumulation index [I[geo]] and Principal Component Analysis [ACP] were applied. Enrichment factors [EFs] and principal component analysis [PCA] revealed two distinct groups of metals. The first group attributed to Mn, Fe and Al that were derived from natural sources, and the second group contained Cu, Zn, Pb, Cd and Cr mainly originated from man-made sources. The contribution rates of these later in terms of the sediment's enrichment exceed 98%. The geoaccumulation index [I[geo]] values explained that only Zn, Pb, Cd and Cr can be considered as moderate to extreme pollutants both in surface and sub-surface sediments


Subject(s)
Geologic Sediments/chemistry , Metals, Heavy
13.
An. acad. bras. ciênc ; 83(3): 801-816, Sept. 2011. ilus, tab
Article in English | LILACS | ID: lil-595537

ABSTRACT

In this study, the geochemical analysis of ten sediment samples collected along the fluvial system of the Estrela River, which flows into the northern portion of Guanabara Bay, shows the presence of anthropogenic impacts in this area. Concentrations of Fe, Mn, Zn, Cu, Pb, Cr and Ni obtained were slightly higher, when compared with values found innatural environments. The particle size and organic matter content in most of the analyzed stations showed featuresnot conducive to the accumulation of pollutants due to the low organic matter content and the strong presence ofsand fraction. There was also the fractionation of heavy metals in sediments and it was found the prominence ofresidual and reducible phase, besides the significant occurrence of organic fractions in some analyzed stations. Thesefactors, thus, highlight the potential risks of contamination, where the metals associated with the organic phase canbecome bioavailable in processes of dissolution, provided by physico-chemical changes that can occur in this aquaticenvironment.


Neste estudo, analises geoquímicas de dez amostras de sedimentos coletadas ao longo do sistema fluvial do rio Estrela, que deságua na porção norte da Baía de Guanabara, evidenciam a presença de impactos antropogênicos nesta área. As concentrações de Fe, Mn, Zn, Cu, Pb, Cr e Ni obtidas foram ligeiramente elevadas, quando comparados com valores encontrados em ambientes naturais. A granulometria e o teor de matéria orgânica na maioria dos pontos analisados mostraram características não favoráveis à acumulação destes poluentes devido à baixa concentração de matéria orgânica e à forte presença de fração areia. Realizou-se também o fracionamento dos metais pesados nos sedimentos e constatou-se a preeminência da fase residual e redutível, além da ocorrência significativa da fração orgânica em alguns pontos analisados. Estes fatores evidenciam, portanto, riscos potenciais de contaminação, onde os metais associados à fase orgânica podem se tornar biodisponíveis em processos de solubilização, proporcionados por mudanças físico-químicas que podem ocorrer neste ambiente aquático.


Subject(s)
Environmental Monitoring/methods , Geologic Sediments/chemistry , Metals, Heavy/analysis , Rivers/chemistry , Water Pollutants, Chemical/analysis , Brazil
14.
An. acad. bras. ciênc ; 83(3): 863-874, Sept. 2011. ilus, mapas, tab
Article in English | LILACS | ID: lil-595545

ABSTRACT

The sediments from the Coari lake, a “terra firme” lake sculpted into Plio-Pleistocene deposits, and the Acará lake, a flooding-type lake developed on Quaternary sediments in the floodplain of the mid-Solimões river, in the western Amazônia, Brazil, were studied to investigate the environmental condition of their developing. This study includes mineral composition, geochemistry, Pb isotope, palinology, radiocarbon-age and morphological framework of the lakes obtained from SRTM satellite images. The geological and the environmental conditions in the two lakes are highly variable and suggest that their evolution reflect autogenic processes under humid rainforest condition. Although kaolinite, quartz, muscovite, illite, and smectite are the main minerals in both lakes, the geochemistry indicates distinct source, the Acará lake sediments have higher concentrations of Al2O3, Fe2O3, FeO, CaO, K2O, MgO, Na2O, P2O5, Ba, V, Cu, Ni, Zn, Pb, Sr, Li, Y and La and have more radiogenic Pb than the Coari lake sediments. The radiocarbon ages suggest that at 10160 yr BP the Coari lake started to be developed due to avulsion of the Solimões river, and the Acará lake was formed by the meander abandonment of Solimões river retaining its grass dominated shore at ca. 3710 yr BP.


Os sedimentos do lago Coari, de ambiente de terra firme eesculpido nos depósitos do Plio-Pleistocenos, e o Acará, típico lago de várzea e ambos formados nos sedimentos quaternários da planície de inundação do médio Solimões, no oeste da Amazônia, Brasil, foram estudados para investigar as condições ambientais durante sua formação. Este estudo inclui dados da composição mineralógica, química, isótopos de Pb, palinologia, datações de radiocarbono e a configuração morfológica dos lagos obtida por imagens SRTM. As condições geológica e ambiental dos lagos variam e sugerem que suas evoluções refletem processos autogenéticos em condições de floresta úmida e chuvosa. Embora caulinita, quartz, muscovita, illita e esmectita sejam os principais minerais em ambos os lagos, a geoquímica indica fonte distinta, os sedimentos do lago Acará têm maior concentração de Al2O3, Fe2O3, FeO, CaO, K2O, MgO, Na2O, P2O5, Ba, V, Cu, Ni, Zn, Pb, Sr, Li, Y e La e têm mais Pb radiogênico que os sedimentos do lago Coari. As idades de radiocarbono sugerem que há aproximadamente 10160 anos AP o lago Coari iniciou o desenvolvimento devido a avulsão do rio Solimões, enquanto o lago Acará foi formado devido ao abandono de meandro do rio Solimões e retendo o domínio das gramíneas nas suas praias há aproximadamente 3710 anos AP.


Subject(s)
Fresh Water/chemistry , Geologic Sediments/chemistry , Metals, Heavy/analysis , Radiometric Dating/methods , Brazil , Geological Phenomena , Paleontology , Pollen
15.
Ciênc. Saúde Colet. (Impr.) ; 16(8): 3539-3539, ago. 2011. ilus, tab
Article in Portuguese | LILACS | ID: lil-595942

ABSTRACT

O fósforo é um nutriente com fontes finitas e não renováveis, cuja velocidade de exploração é atualmente muito superior às suas taxas de retorno ao seu ciclo natural, sendo que já existem previsões a respeito de um provável colapso nas suas fontes disponíveis e conhecidas, com impactos econômicos, sociais e ambientais graves e irreversíveis. Diante desse cenário, o presente trabalho busca apresentar informações sobre a dinâmica do fósforo no meio ambiente, avaliando os impactos causados pelas atividades humanas e verificando as ações que podem auxiliar na preservação do ciclo do nutriente. Visando contribuir para uma melhor visualização do assunto, foi analisada a evolução dos dados relativos à concentração populacional, número de industriais e extensão das áreas cultivadas em uma bacia hidrográfica, em relação às concentrações de fósforo nos compartimentos água e sedimento, ao longo de 22 anos. Para tanto, utilizou-se o rio Tietê como estudo de caso. Os resultados obtidos indicam que o controle das fontes domésticas, principalmente da quantidade de tripolifosfato de sódio (STPP) utilizada nos detergentes, é de grande importância para a melhoria da qualidade das águas, proteção ao meio ambiente e garantia da saúde pública.


Phosphorus is a nutrient with finite and non-renewable sources, the speed of exploitation of which is currently far higher than the rates of return to its natural cycle. It is already being predicted that available and known sources will soon be exhausted, with serious and irreversible economic, social and environmental impacts. In this context, this study sets out to present information about the dynamics of phosphorus in the environment, assessing the impacts caused by human activities and establishing what actions might contribute to preservation of the nutrient cycle. To contribute to enhanced understanding of the topic, the evolution of data on population density, the number of industries and the extension of cultivated areas in a river basin, was studied over 22 years in relation to concentrations of phosphorus in water and sediment. The Tietê River was used for the case study. The results revealed that the control of domestic effluent, especially the amount of sodium tripolyphosphate (STPP) used in detergents and soap products, is of major importance for improving water quality, ensuring environmental protection and safeguarding public health.


Subject(s)
Humans , Environment , Geologic Sediments/chemistry , Phosphorus/analysis , Public Health , Rivers/chemistry , Sewage/chemistry , Urbanization
16.
Braz. j. biol ; 71(3): 673-678, Aug. 2011. ilus, graf
Article in English | LILACS | ID: lil-597174

ABSTRACT

This paper estimates annual P emission to the Jaguaribe River estuary, NE Brazil, responsible for approximately 30 percent of the country's farmed shrimp production. Emissions increased three times between 2001 and 2006 and reached 43.9 t.year-1. These emissions make aquaculture the third main source of P for this estuary and are much smaller than emissions from agricultural sources and slightly lower than emissions from wastewater. Their relative contribution also increased from 10.5 percent to 20.5 percent. Temporal variability of P concentrations in estuarine bottom sediments also suggest an increase, but not as evident as the emissions. The spatial distribution and speciation of P (total P and inorganic P) in sampling stations located upstream and downstream from the main aquaculture area confirmed the importance of this source. Inorganic P was the dominant form present in sediments downstream and showed an increase from 67 percent to 75 percent of the total P present in the sediment.


É apresentada uma estimativa da emissão anual de P para o estuário do rio Jaguaribe, Ceará, Nordeste do Brasil, área responsável por cerca de 30 por cento da produção total de camarão cultivado no país. As emissões aumentaram por um fator de três entre 2001 e 2006, atingindo 43,9 t.year-1. Essa emissão coloca a aquacultura como a terceira fonte principal de P para esse estuário, sendo bem menor que a emissão de fontes agrícolas e um pouco menor que as emissões por águas servidas. A contribuição relativa da aquacultura também aumentou de 10,5 por cento a 20,5 por cento, no mesmo período. A variação temporal das concentrações de P em sedimentos estuarinos sugere um aumento no período, porém não tão evidente quanto das emissões. A distribuição espacial e a especiação do P (P total e P inorgânico) em estações de coleta localizadas à montante e à jusante da principal área de aquacultura confirmaram a importância desta fonte. O P inorgânico foi a forma dominante presente em sedimentos à jusante e mostrou um aumento de 67 por cento a 75 por cento do total de P presente no sedimento.


Subject(s)
Animals , Environmental Monitoring/methods , Geologic Sediments/chemistry , Phosphorus/analysis , Rivers/chemistry , Water Pollutants, Chemical/analysis , Aquaculture , Brazil
17.
Braz. j. biol ; 71(2): 437-446, maio 2011. graf, mapas, tab
Article in English | LILACS | ID: lil-592579

ABSTRACT

The Oligochaeta forms an important part of the macroinvertebrates inhabiting sediments of lotic ecosystems. It has an important role in the cycling of matter and energy transfer in these environments. The aim of this study is to analyse limnological variables, their influence on the structure and diversity of benthic oligochaete taxocenosis in a stretch of the Upper São Francisco River and its tributary the Piumhi River. Samples were taken in two climatic periods, the dry season in October 2006 and 2007 and the rainy season in March 2007 and 2008 at three points along the Piumhi River and six points along the São Francisco River. The sediment of the São Francisco consisted predominantly of sand and clay, whereas the sediment of the Piumhi was mainly sandy. Six species of oligochaete occurred in the Piumhi River while seven were found in the São Francisco. Of these, Pristina synclites Stephenson, 1925, Pristina americana Cernosvitov, 1937, Bothrioneurum sp. Stolc, 1888 and Limnodrilus hoffmeisteri Claparede, 1862 occurred in the sediment of both rivers. L. hoffmeisteri showed the highest numerical abundance in the Piumhi River and Brinkhurstia americana (Brinkhurst, 1964) and L. neotropicus Cernosvitov, 1939 were the most abundant species in the São Francisco River. The highest oligochaete density was recorded in the Piumhi during the dry seasons. Canonical correspondence analyses (CCA) of sediment characteristics explained most of the data variability and the association of the presence of oligochaete species in the Piumhi and São Francisco Rivers with the limnological variables (grain size composition and total nitrogen and phosphorus concentrations in the sediment).


Os Oligochaeta constituem uma parte importante dos macroinvertebrados bentônicos que habitam os sedimentos dos ecossistemas lóticos e tem papel relevante na ciclagem da matéria e transferência de energia nestes ambientes. O objetivo deste trabalho foi analisar as variáveis limnológicas e suas incidências sobre a estrutura e a diversidade da taxocenose de Oligochaeta presentes na comunidade bentônica de um trecho do alto rio São Francisco e de seu tributário, rio Piumhi. As coletas foram realizadas em dois períodos climáticos, o seco em outubro de 2006 e 2007 e o chuvoso em março de 2007 e 2008, amostrando-se três pontos no rio Piumhi e seis pontos no rio São Francisco. Os sedimentos do rio São Francisco foram predominantemente arenosos e argilosos, e no rio Piumhi ocorreram principalmente substratos arenosos. No rio Piumhi, ocorreram seis espécies de oligoquetos, enquanto que no rio São Francisco registrou-se a presença de sete espécies. Destas, Pristina synclites Stephenson, 1925, Pristina americana Cernosvitov, 1937, Bothrioneurum sp. Stolc, 1888 e Limnodrilus hoffmeisteri Claparede, 1862 ocorreram no sedimento de ambos os rios. L. hoffmeisteri foi registrada com maior abundância numérica no rio Piumhi e Brinkhurstia americana (Brinkhurst, 1964) e L. neotropicus Cernosvitov, 1939 foram as espécies mais abundantes no rio São Francisco. Os maiores valores de densidade foram registrados no rio Piumhi durante os períodos secos. As análises de correspondência canônica (CCA) para as características do sedimento permitiram explicar a variabilidade dos dados, associando a composição de espécies Oligochaeta, presentes nos rios Piumhi e São Francisco, com as variáveis limnológicas (composição granulométrica e concentrações de nitrogênio e fósforo total no sedimento).


Subject(s)
Animals , Biodiversity , Geologic Sediments/chemistry , Oligochaeta/classification , Rivers/chemistry , Brazil , Environment , Nitrogen/analysis , Population Density , Phosphorus/analysis , Seasons
18.
Rev. biol. trop ; 58(supl.3): 129-140, Oct. 2010. ilus, graf, tab
Article in Spanish | LILACS | ID: lil-638093

ABSTRACT

Heavy metal distribution in superficial sedimenta ta Saco, Gulf of Cariaco, Sucre, Venezuela. The Gulf of Cariaco is a marine ecosystem with high primary productivity, which gives it an ecological and socioeconomic importance. Nevertheless, anthropogenic activities around the Gulf produce wastes that are deposited directly or by runoff into the sediments, and consequently, increases concentrations of metals in this ecosystem. The objective of this study was to determine the distribution of cadmium, copper, lead, manganese, nickel and zinc in geochemical fractions of surface sediments, using modified BCR sequential extraction procedure. The concentrations were measured using flame atomic absorption spectroscopy. In addition, the contents of soluble and exchangeable metals associated to carbonate fractions, determined by BCR, were compared with those determined by the method of Campanella. Samples were collected in 12 stations during June 2007. The applied methodologies were evaluated with a certified reference material of marine sediments (HISS-1) and the results indicated that these methods provide adequate accuracy and precision for the extraction of metals. The total metal concentrations (μg g-1) were, Cd: < limit of detection (LD)-5.0; Pb: 1.79-60.41; Cu: no detected (ND)-42.18; Zn: 25.13-104.57; Mn: 66.31-80.29 and Ni: 3.29-24.58. Cd, Cu, Ni and Pb at several stations, exceeded the Canadian Sediment Quality Guidelines of the Lowest Effect Levels (LEL). Cadmium was identified as being the most mobile of the elements, having the highest concentrations in soluble and exchangeable cations and carbonates. However, Pb, Cu, Mn and Zn levels were found highly associated to organic matter and sulfide fractions. The methods did not show significant statistical differences for the extraction of soluble and exchangeable cations and the metals associated to carbonate fraction. There are several significant correlations between heavy metals, which suggest their common origin. Rev. Biol. Trop. 58 (Suppl. 3): 129-140. Epub 2010 October 01.


El Golfo de Cariaco es un ecosistema marino con mucha productividad primaria, lo que le confiere especial importancia ecológica y socioeconómica. Sin embargo, los desechos de las actividades antropogénicas son descargados directamente o arrastradas por las escorrentías. El objetivo de este estudio fue determinar la distribución de cadmio, cobre, plomo, manganeso, níquel y zinc en las fracciones geoquímica de los sedimentos superficiales, usando el método modificado de extracción secuencial de la Comunidad Europea (BCR). Las concentraciones de los metales fueron medidas por espectroscopía de absorción atómica. Además, se compararon los contenidos de metales intercambiables y asociados a los carbonatos determinados por el procedimiento BCR modificado con los determinados por el método de Campanella. La recolección de muestras se hizo en 12 estaciones del sector oriental del Golfo de Cariaco, Estado Sucre, específicamente en el sector conocido como el Saco, en junio 2007. Las metodologías aplicadas fueron evaluadas usando un material de referencia certificado de sedimentos marino (HISS - 1). Los resultados indicaron que los métodos proveen exactitud y precisión adecuadas para la extracción de metales. Las concentraciones totales (μg g-1) fueron, Cd: < límite de detección (LD)-5.0; Pb: 1.79- 60.41; Cu: no detectado (ND)-42.18; Zn: 25.13-104.57; Mn: 66.31-80.29 y Ni: 3.29-24.58. Cd, Cu, Ni y Pb excedieron en varias estaciones los límites que pueden afectar la biota, establecidos por la Guía de Evaluación de la Calidad de los Sedimentos de Canadá. El cadmio fue el metal identificado como el más móvil, teniendo las más altas concentraciones como intercambiable y asociado a las fracciones de carbonatos. Sin embargo, Pb, Cu, Mn y Zn mostraron su mayor abundancia en la fracción asociada a materia orgánica y azufre. Los métodos no presentan diferencias significativas para extraer la primera fracción. Se encontraron significantes correlaciones entre los metales pesados que sugieren su origen común.


Subject(s)
Environmental Monitoring/methods , Geologic Sediments/chemistry , Metals, Heavy/analysis , Water Pollutants, Chemical/analysis , Venezuela
19.
Braz. j. biol ; 69(3): 851-858, Aug. 2009. graf, mapas, tab
Article in English | LILACS | ID: lil-527153

ABSTRACT

We present the distribution of Cu in water, sediments and biomass from intensive shrimp (Litopenaeus vannamei Boone, 1931)) farming in northeastern Brazil. The results show no difference in dissolved Cu concentrations between waters entering and leaving the ponds. However, there was a large export of particulate Cu to adjacent environments, showed by extremely high particulate (112 µg.L-1) Cu concentrations in draining waters. Copper concentrations in the bottom sediments of the pond varied with depth from 10 to 20 µg.g-1, being 5 to 7 times higher than the local background. Pond management procedures result in a peculiar vertical distribution of Cu with peak values occurring at sub-surface depths in pond bottom sediments. Bioavailable Cu reaches about 20 percent of the total Cu content in sediments. Notwithstanding the relatively high Cu bioavailability, concentrations in shrimp muscle (23.2 to 63.4 µg.g-1 d.w.) were similar to reported values for reared and natural L. vannamei populations, and much lower than acceptable maximum limits for human consumption. Concentrations in the exoskeleton were always higher than in muscle. Increasing Cu mass, and to a lesser extent Cu concentrations in muscle tissues, occurred simultaneously to a decrease in Cu mass and concentrations in the exoskeleton and vice versa, suggesting a dynamical exchange of Cu between the two compartments. Although Cu fate in intensive shrimp culture does not result in increasing Cu exposure to consumers, the activity is an important source of this metal to adjacent ecosystems, in particular in the pristine environments where most aquaculture activities in NE Brazil takes place.


Este trabalho apresenta a distribuição de Cu em água, sedimentos e biomassa em uma fazenda de cultivo intensivo do camarão Litopenaeus vannamei Boone, 1931, no Nordeste do Brasil. Os resultados mostraram não haver diferenças entre as concentrações de Cu nas águas afluentes e efluentes da fazenda. Entretanto, foi verificada uma grande exportação de Cu para áreas adjacentes associada ao material em suspensão. Nas águas efluentes, a concentração de Cu particulado atingiu até 112 µg.L-1. Em sedimentos, as concentrações de Cu variaram com a profundidade da coluna sedimentar de 10 a 20 µg.g-1, sendo estes valores de 5 a 7 vezes mais altos que as concentrações naturais dos solos e sedimentos locais. O manejo dos tanques de criação resulta em perfis de distribuição de Cu em sedimentos com maiores concentrações em subsuperfície. A biodisponibilidade do Cu nestes sedimentos é elevada e atinge cerca de 20 por cento da concentração total. Apesar da biodisponibilidade elevada, as concentrações de Cu em músculo do L. vannamei (23.2 a 63.4 µg.g-1 peso seco) são similares aos valores reportados para populações naturais da espécie e em diversos de cultivo em outros países, e estão bem abaixo dos limites máximos permitidos para consumo humano. As concentrações de Cu no exoesqueleto foram maiores que no músculo. Um aumento da massa de Cu em músculo ocorreu simultaneamente à diminuição do Cu no exoesqueleto e vice-versa sugerindo uma troca dinâmica do Cu entre os dois compartimentos. Embora a presença do Cu no cultivo intensivo do L. vannamei não represente exposição significativa para os consumidores, a atividade é fonte importante de Cu para os sistemas aquáticos adjacentes.


Subject(s)
Animals , Humans , Aquaculture , Copper/pharmacokinetics , Geologic Sediments/chemistry , Penaeidae/chemistry , Biological Availability , Copper/analysis , Reference Values , Water Pollutants, Chemical/analysis
20.
Lebanese Science Journal. 2009; 10 (2): 33-48
in English | IMEMR | ID: emr-134421

ABSTRACT

Cd and Pb extractability with EDTA were measured from sediment samples collected at three contrasted sites along the Lebanese coastal zones: Akkar, Dora and Selaata. Akkar is located away from any direct source of contamination, while Dora and Selaata receive respectively urban and industrial wastes. The extractability of Cd and Pb from sediments of the aforementioned sites was studied by applying kinetic and equilibrium extractions with EDTA 0.05M. The adjustment of Pb kinetic extractions curves to a two-first order reactions model permitted to kinetically fractionate Pb in the studied sediments into three fractions [readily extractable, less extractable and non extractable] and allowed to conclude that Pb in Selaata represents the highest environmental risk


Subject(s)
Lead , Edetic Acid , Geologic Sediments/chemistry
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