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1.
Rev. bras. plantas med ; 17(4,supl.3): 1177-1181, 2015. tab
Artigo em Português | LILACS | ID: lil-776595

RESUMO

RESUMO O presente trabalho teve como objetivo avaliar a propagação vegetativa do assa-peixe Vernonia polyanthes Less utilizando estacas apicais e diferentes substratos. O experimento foi conduzido em condições de casa de vegetação com irrigação controlada na Faculdade de Ciências Agronômicas da UNESP campus Botucatu- SP. O delineamento experimental utilizado foi o inteiramente casualizado, com sete tratamentos (Solo de textura argilosa; 50% Solo de textura argilosa + 50% Húmus; Solo de textura média; 50% Solo de textura média + 50% Húmus; Solo de textura arenosa; 50% Solo de textura arenosa + 50% Húmus; Húmus) e quatro repetições, sendo 10 estacas por repetição. As características avaliadas foram: comprimento da maior raiz, comprimento da parte aérea, número de brotações, porcentagem de enraizamento, volume radicular, nota para qualidade das estacas e massa seca da parte aérea e das raízes. Os dados foram submetidos à análise de variância pelo teste F e as médias comparadas pelo teste de Scott & Knott a 5% de probabilidade. Para a análise estatística, utilizou-se o programa SISVAR ®. A partir da análise, observou-se efeito altamente significativo dos tratamentos utilizados para todas as variáveis analisadas, com exceção da massa seca da parte aérea, que não apresentou diferença significativa. Para obtenção de melhor enraizamento da espécie em questão, o recomendado é a utilização do substrato: solo de textura argilosa ou média, acrescido de húmus na proporção de 1:1.


ABSTRAT The current study aimed to evaluate the vegetative propagation of assa-peixe using apical cuttings and different substrates. The trial was conducted under greenhouse conditions with controlled irrigation, in the Faculdade de Ciências Agronômicas of UNESP in Botucatu- SP campus. The experimental design was completely randomized, with seven treatments and four replications, with 10 cuttings per replicate. The characteristics were: longest root length, shoot length, number of shoots, rooting percentage, root volume, score of quality of cuttings and dry mass of shoots and roots. The data were subjected to analysis of variance by F test and the averages were compared by the Scott Knott test at 5% probability. For statistical analysis, we used the SISVAR ®. From the analysis, we observed highly relevant effect of the treatments used for all variables, with the exception of the dry weight of shoots, which did not present significant difference. In order to obtain a better rooting of the species concerned, the recommended method would be to use substrates such as clayey soil or medium plus humus in the ratio 1:1.


Assuntos
Solo/análise , Vernonia/classificação , Análise de Variância , Pradaria , Plantas Medicinais/classificação , Análise Estatística
2.
Pak J Biol Sci ; 16(5): 239-44, 2013 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-24175434

RESUMO

Ecosystem function is affected by management activities in rangeland ecosystems. Hence, it is necessary to consider management effects on rangeland ecosystem to reduce its degradation. In order to determine the effects of management activities on rangeland ecosystem, four management treatments were chosen in Taleghan, Iran. Functionality characteristics including: stability, infiltration and nutrient cycling were calculated using Landscape Function Analysis (LFA). LFA calculates these parameters using 11 soil surface indicators. Results showed that stability, infiltration and nutrient cycle were higher in Karkaboud than the other locations because of low grazing pressure and non-accessibility conditions. As grazing pressure increased we witnessed less stability, infiltration and nutrient cycling in Karkaboud cascade, Kouin and Kouin-Marjan. Main causes of decline in stability, infiltration and nutrient cycling are perennial vegetation removal, soil trampling and decrease in soil organic matter and subsequent increase in erosion and soil instability.


Assuntos
Ecossistema , Monitoramento Ambiental , Alimentos , Solo/análise , Irã (Geográfico) , Solo/química
3.
Zh Obshch Biol ; 74(3): 190-200, 2013.
Artigo em Russo | MEDLINE | ID: mdl-24163983

RESUMO

Nitrogen and carbon contents of fine roots were studied for 92 alpine plant species in the Northwest Caucasus. Nitrogen content ranged from 0.43% (Bromus variegatus) to 3.75% (Corydalis conorhiza) with mean value 1.3%. Carbon content ranged from 40.3% (Corydalis conorhiza) to 51.7% (Empetrum nigrum) with mean value 43.4%. C:N ratio was found to be 34:1 which is higher than the worldwide mean. Eudicot's roots had higher N concentration (1.37 +/- 0.07) than monocot's ones (0.95 +/- 0.09). Among the life forms, carbon content increased in the following order: geophytes < hemicriptophytes < chamaephytes. Specific root length positively correlated with nitrogen root content and negatively--with carbon root content. Species with larger leaves and higher specific root area had more nitrogen and less carbon in roots in comparison with species with small leaves. There were positive correlations between leaf and root nitrogen, as well as carbon, contents. Regrowth rate; seed size, aboveground biomass, and vegetation mobility were not related with root nitrogen content. Our results corroborate the poor and rich soil adaptation syndromes. Species of competitive and ruderal (sensu Grime) strategies are more typical for alpine meadows and snow bed communities. They had higher nitrogen contents in leaves and roots, larger leaves with higher water content and higher rate of seed production. On the other hand, stress-tolerant plants had higher carbon and less nitrogen concentrations in their roots and leaves, smaller leaves and specific leaf area.


Assuntos
Carbono/metabolismo , Nitrogênio/metabolismo , Folhas de Planta/química , Raízes de Plantas/química , Plantas/química , Sementes/química , Adaptação Fisiológica , Altitude , Biomassa , Ecossistema , Folhas de Planta/anatomia & histologia , Raízes de Plantas/anatomia & histologia , Plantas/anatomia & histologia , Sementes/anatomia & histologia , Solo/análise , Água/metabolismo
4.
J Air Waste Manag Assoc ; 63(9): 1036-45, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24151679

RESUMO

The concentrations of airborne particulate matter (PM) in Navrongo, a town in the Sahel Savannah Zone of Ghana, have been measured and the major sources have been identified. This area is prone to frequent particulate pollution episodes due to Harmattan dust and biomass burning, mostly from annual bushfires. The contribution of combustion emissions, particularly from biomass and fossil fuel, to ambient air particulate loadings was assessed. Sampling was conducted from February 2009 to February 2010 in Navrongo. Two Gent samplers were equipped to collect PM10 in two size fractions, coarse (PM10-2.5) and fine (PM2.5). Coarse particles are collected on a coated, 8-microm-pore Nuclepore filter. Fine particle samples were sampled with 47-mm-diameter Nuclepore and quartz filters. Elemental carbon (EC) and organic carbon (OC) concentrations were determined from the quartz filters using thermal optical reflectance (IMPROVE/TOR) methods. Elements were measured on the fine-particle Nuclepore filters using energy-dispersive x-ray fluorescence. The average PM2.5 mass concentration obtained at Navrongo was 32.3 microg/m. High carbonaceous concentrations were obtained from November to March, the period of Harmattan dust and severe bush fires. Total carbon was found to contribute approximately 40% of the PM2.5 particulate mass. Positive matrix factorization (PMF) suggested six major sources contributing to the PM2.5 mass. They are two stroke engines, gasoline emissions, soil dust, diesel emissions, biomass burning, and resuspended soil dust. Biomass combustion (16.0%) was identified as second most important source next to soil dust at Navrongo.


Assuntos
Biomassa , Carbono/análise , Fogo , Material Particulado/análise , Gana , Material Particulado/química , Estações do Ano , Solo/análise
5.
Proc Natl Acad Sci U S A ; 110(38): E3631-9, 2013 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-24003150

RESUMO

Although the function of silicon (Si) in plant physiology has long been debated, its beneficial effects on plant resistance against abiotic and biotic stresses, including insect herbivory, have been well documented. In addition, the jasmonate (JA) signaling pathway plays a crucial role in mediating antiherbivore defense responses in plants. However, potential interactions between JA and Si in response to insect attack have not been examined directly. To explore the role JA may play in Si-enhanced resistance, we silenced the expression of allene oxide synthase (OsAOS; active in JA biosynthesis) and CORONATINE INSENSITIVE1 (OsCOI1; active in JA perception) genes in transgenic rice plants via RNAi and examined resulting changes in Si accumulation and defense responses against caterpillar Cnaphalocrocis medinalis (rice leaffolder, LF) infestation. Si pretreatment increased rice resistance against LF larvae in wild-type plants but not in OsAOS and OsCOI1 RNAi lines. Upon LF attack, wild-type plants subjected to Si pretreatment exhibited enhanced defense responses relative to untreated controls, including higher levels of JA accumulation; increased levels of transcripts encoding defense marker genes; and elevated activities of peroxidase, polyphenol oxidase, and trypsin protease inhibitor. Additionally, reduced Si deposition and Si cell expansion were observed in leaves of OsAOS and OsCOI1 RNAi plants in comparison with wild-type plants, and reduced steady-state transcript levels of the Si transporters OsLsi1, OsLsi2, and OsLsi6 were observed in Si-pretreated plants after LF attack. These results suggest a strong interaction between Si and JA in defense against insect herbivores involving priming of JA-mediated defense responses by Si and the promotion of Si accumulation by JA.


Assuntos
Ciclopentanos/metabolismo , Mariposas/fisiologia , Oryza/metabolismo , Oxilipinas/metabolismo , Transdução de Sinais/fisiologia , Silício/metabolismo , Solo/análise , Animais , Catecol Oxidase/metabolismo , Inativação Gênica , Proteínas de Choque Térmico/genética , Herbivoria/fisiologia , Oxirredutases Intramoleculares/genética , Oryza/fisiologia , Peroxidase/metabolismo , Silício/análise , Inibidores da Tripsina/metabolismo
8.
ScientificWorldJournal ; 2013: 454710, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23844398

RESUMO

The paper deals with the influence of soil genesis on the physical-mechanical properties. The presented case study was conducted in the region of the Ostrava Basin where there is a varied genetic composition of the Quaternary geological structure on the underlying Neogeneous sediments which are sediments of analogous granulometry but different genesis. In this study, 7827 soil samples of an eolian, fluvial, glacial, and deluvial origin and their laboratory analyses results were used. The study identified different values in certain cases, mostly in coarser-grained foundation soils, such as sandy loam S4 (MS) and clayey sand F4 (CS). The soils of the fluvial origin manifest different values than other genetic types. Next, based on regression analyses, dependence was proved neither on the deposition depth (depth of samples) nor from the point of view of the individual foundation soil classes or the genetic types. The contribution of the paper is to point at the influence of genesis on the foundation soil properties so that engineering geologists and geotechnicians pay more attention to the genesis during engineering-geological and geotechnical investigations.


Assuntos
Sedimentos Geológicos/análise , Sedimentos Geológicos/química , Solo/análise , Solo/química , Força Compressiva , Teste de Materiais , Tamanho da Partícula , Propriedades de Superfície
10.
Water Sci Technol ; 68(1): 124-33, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23823548

RESUMO

This paper describes a sediment delivery ratio (SDR) using the Geographic Information System (GIS)-based Revised Universal Soil Loss Equation (RUSLE), to calculate the soil loss and sediment rating curve (SRC) basis of measured data in the six basins of Four Rivers, South Korea. The data set for calculating SDR was prepared during 3 years from 2008 to 2010. Mean soil loss in the six basins of Four Rivers was 515-869 t km(-2) yr(-1) and mean specific sediment yield (SSY) was 20-208 t km(-2) yr(-1) with basin size. The SDR ranged from 0.03 to 0.33 in the six rivers. Most sediment flows in the monsoon period from June to September (mean Max.: >97%; mean Min.: >84%), but SDR is lower than those of similar continental river basins. This is due to environmental factors, for example rainfall characteristics and associated run-off, soil characteristics and cultivated patterns with increasing basin size. This research provides the first application of SDR based on the observed field data in South Korea.


Assuntos
Sistemas de Informação Geográfica , Sedimentos Geológicos/análise , Solo/análise , Monitoramento Ambiental , Oceanos e Mares , República da Coreia
11.
BMC Plant Biol ; 13: 95, 2013 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-23815794

RESUMO

BACKGROUND: The cuticle is a hydrophobic barrier located at the aerial surface of all terrestrial plants. Recent studies performed on model plants, such as Arabidopsis thaliana, have suggested that the cuticle may be involved in drought stress adaptation, preventing non-stomatal water loss. Although forest trees will face more intense drought stresses (in duration and intensity) with global warming, very few studies on the role of the cuticle in drought stress adaptation in these long-lived organisms have been so far reported. RESULTS: This aspect was investigated in a conifer, maritime pine (Pinus pinaster Ait.), in a factorial design with two genetic units (two half-sib families with different growth rates) and two treatments (irrigated vs non-irrigated), in field conditions. Saplings were grown in an open-sided greenhouse and half were irrigated three times per week for two growing seasons. Needles were sampled three times per year for cuticular wax (composition and content) and transcriptome (of 11 genes involved in cuticle biosynthesis) analysis. Non-irrigated saplings (i) had a higher cuticular wax content than irrigated saplings and (ii) overexpressed most of the genes studied. Both these trends were more marked in the faster growing family. CONCLUSIONS: The higher cuticular wax content observed in the non-irrigated treatment associated with strong modifications in products from the decarbonylation pathway suggest that cuticular wax may be involved in drought stress adaptation in maritime pine. This study provides also a set of promising candidate genes for future forward genetic studies in conifers.


Assuntos
Pinus/metabolismo , Proteínas de Plantas/genética , Água/metabolismo , Ceras/metabolismo , Secas , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Pinus/genética , Pinus/crescimento & desenvolvimento , Proteínas de Plantas/metabolismo , Solo/análise , Água/análise , Ceras/química
12.
Water Sci Technol ; 68(2): 486-93, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23863445

RESUMO

The retention of heavy metals at two pilot-scale treatment wetlands (TWs), consisting of two vertical flow beds (VSSF) followed by a horizontal flow bed (HSSF) was studied. The TWs received high-strength wastewater: reject waters from sewage sludge centrifugation (RW) and landfill leachate (LL). The concentrations of the metals Fe, Mn, Zn, Al, Pb, Cu, Cd, Co, and Ni were measured in treated wastewater, substrate of the beds and in plant material harvested from the beds (separately in above ground (ABG) parts and below ground (BG) parts). The TWs differed in metals retention. In the RW treating TW the metal removal efficiencies varied from 27% for Pb to over 97% for Fe and Al. In the LL treating system the concentrations of most metals decreased after VSSF-1 and VSSF-2 beds; however, in the outflow from the last (HSSF) bed, the concentrations of metals (apart from Al) increased again, probably due to the anaerobic conditions at the bed. A major removal pathway was sedimentation and adsorption onto soil substrate as well as precipitation and co-precipitation. In the LL treating facility the plants contained substantially higher metal concentrations in BG parts, while the upward movement of metals was restricted. In the RW treating facility the BG/ABG ratios were lower, indicating that metals were transported to shoots.


Assuntos
Alumínio/análise , Metais Pesados/análise , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análise , Áreas Alagadas , Adsorção , Alumínio/química , Alumínio/metabolismo , Biodegradação Ambiental , Sedimentos Geológicos/análise , Sedimentos Geológicos/química , Metais Pesados/química , Metais Pesados/metabolismo , Brotos de Planta/química , Brotos de Planta/metabolismo , Poaceae/química , Poaceae/metabolismo , Solo/análise , Solo/química , Águas Residuárias/análise , Águas Residuárias/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/metabolismo
13.
Pak J Pharm Sci ; 26(4): 805-11, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23811462

RESUMO

An integrated study of rocks, soils and fruits of Manilkara zapota (L.) (Sapotaceae) of Winder area have been carried out to elaborate trace elements relationship between them. The igneous rocks of the study area have elevated amount of certain trace elements, upon weathering these elements are concentrated in the soil of the area. The trace elements concentration in the soil were found in the range of 0.8-197 for Fe, 1.23-140 for Mn, 0.03-16.7 for Zn, 0.07-9.8 for Cr, 0.05-2.0 for Co, 0.52-13.3 for Ni, 0.03-8.8 for Cu, 0.08-10.55 for Pb and 0.13-1.8µg/g for Cd. The distribution pattern of elements in the rocks and soils reflected genetic affiliation. Promising elements of edible part of the fruit were Fe (14.17), Mn (1.49), Cr (2.96), Ni (1.13), Co (0.92), Cu (1.70) and Zn (1.02µg/g). The concentration of these elements in the fruits is above the optimum level of recommended dietary intake, probably due to this, disorder in the human health is suspected in the inhabitants of the area.


Assuntos
Geologia , Manilkara/química , Solo/análise , Oligoelementos/análise , Frutas/química , Paquistão
14.
Proc Natl Acad Sci U S A ; 110(29): 12149-54, 2013 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-23818612

RESUMO

Understanding spatial distributions, synergies, and tradeoffs of multiple ecosystem services (benefits people derive from ecosystems) remains challenging. We analyzed the supply of 10 ecosystem services for 2006 across a large urbanizing agricultural watershed in the Upper Midwest of the United States, and asked the following: (i) Where are areas of high and low supply of individual ecosystem services, and are these areas spatially concordant across services? (ii) Where on the landscape are the strongest tradeoffs and synergies among ecosystem services located? (iii) For ecosystem service pairs that experience tradeoffs, what distinguishes locations that are "win-win" exceptions from other locations? Spatial patterns of high supply for multiple ecosystem services often were not coincident; locations where six or more services were produced at high levels (upper 20th percentile) occupied only 3.3% of the landscape. Most relationships among ecosystem services were synergies, but tradeoffs occurred between crop production and water quality. Ecosystem services related to water quality and quantity separated into three different groups, indicating that management to sustain freshwater services along with other ecosystem services will not be simple. Despite overall tradeoffs between crop production and water quality, some locations were positive for both, suggesting that tradeoffs are not inevitable everywhere and might be ameliorated in some locations. Overall, we found that different areas of the landscape supplied different suites of ecosystem services, and their lack of spatial concordance suggests the importance of managing over large areas to sustain multiple ecosystem services.


Assuntos
Agricultura/métodos , Conservação dos Recursos Naturais/métodos , Ecossistema , Modelos Teóricos , Urbanização/tendências , Carbono/metabolismo , Análise Fatorial , Sistemas de Informação Geográfica , Água Subterrânea , Recreação/economia , Solo/análise , Abastecimento de Água , Wisconsin
15.
Environ Microbiol Rep ; 5(3): 404-13, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23754721

RESUMO

Agricultural systems rely on healthy soils and their sustainability requires understanding the long-term impacts of agricultural practices on soils, including microbial communities. We examined the impact of 17 years of land management on soil bacterial communities in a New Zealand randomized-block pasture trial. Significant variation in bacterial community structure related to mowing and plant biomass removal, while nitrogen fertilizer had no effect. Changes in soil chemistry and legume abundance described 52% of the observed variation in the bacterial community structure. Legumes (Trifolium species) were absent in unmanaged plots but increased in abundance with management intensity; 11% of the variation in soil bacterial community structure was attributed to this shift in the plant community. Olsen P explained 10% of the observed heterogeneity, which is likely due to persistent biomass removal resulting in P limitation; Olsen P was significantly lower in plots with biomass removed (14 mg kg(-1) ± 1.3SE) compared with plots that were not mown, or where biomass was left after mowing (32 mg kg(-1) ± 1.6SE). Our results suggest that removal of plant biomass and associated phosphorus, as well as shifts in the plant community, have greater long-term impacts on soil bacterial community structure than application of nitrogen fertilizers.


Assuntos
Bactérias/crescimento & desenvolvimento , Consórcios Microbianos/fisiologia , Fósforo/deficiência , Microbiologia do Solo , Solo/análise , Agricultura/métodos , Bactérias/classificação , Biomassa , Ecossistema , Fabaceae/química , Fertilizantes/análise , Nova Zelândia , Nitrogênio/análise , Poaceae/química , Dinâmica Populacional
16.
ScientificWorldJournal ; 2013: 579460, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23766698

RESUMO

Particle size distribution (PSD) is a fundamental physical property of soils. Traditionally, the PSD curve was generated by hand from limited data of particle size analysis, which is subjective and may lead to significant uncertainty in the freehand PSD curve and graphically estimated cumulative particle percentages. To overcome these problems, a log-cubic method was proposed for the generation of PSD curve based on a monotone piecewise cubic interpolation method. The log-cubic method and commonly used log-linear and log-spline methods were evaluated by the leave-one-out cross-validation method for 394 soil samples extracted from UNSODA database. Mean error and root mean square error of the cross-validation show that the log-cubic method outperforms two other methods. What is more important, PSD curve generated by the log-cubic method meets essential requirements of a PSD curve, that is, passing through all measured data and being both smooth and monotone. The proposed log-cubic method provides an objective and reliable way to generate a PSD curve from limited soil particle analysis data. This method and the generated PSD curve can be used in the conversion of different soil texture schemes, assessment of grading pattern, and estimation of soil hydraulic parameters and erodibility factor.


Assuntos
Algoritmos , Modelos Estatísticos , Tamanho da Partícula , Solo/análise , Solo/química , Simulação por Computador , Distribuições Estatísticas
17.
ScientificWorldJournal ; 2013: 698752, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23766704

RESUMO

Limited data are available on the ectomycorrhizae-induced changes in surface structure and composition of soil colloids, the most active portion in soil matrix, although such data may benefit the understanding of mycorrhizal-aided soil improvements. By using ectomycorrhizae (Gomphidius viscidus) and soil colloids from dark brown forest soil (a good loam) and saline-alkali soil (heavily degraded soil), we tried to approach the changes here. For the good loam either from the surface or deep soils, the fungus treatment induced physical absorption of covering materials on colloid surface with nonsignificant increases in soil particle size (P > 0.05). These increased the amount of variable functional groups (O-H stretching and bending, C-H stretching, C=O stretching, etc.) by 3-26% and the crystallinity of variable soil minerals (kaolinite, hydromica, and quartz) by 40-300%. However, the fungus treatment of saline-alkali soil obviously differed from the dark brown forest soil. There were 12-35% decreases in most functional groups, 15-55% decreases in crystallinity of most soil minerals but general increases in their grain size, and significant increases in soil particle size (P < 0.05). These different responses sharply decreased element ratios (C:O, C:N, and C:Si) in soil colloids from saline-alkali soil, moving them close to those of the good loam of dark brown forest soil.


Assuntos
Coloides/química , Minerais/química , Micorrizas/química , Micorrizas/fisiologia , Solo/química , Coloides/análise , Cristalização , Teste de Materiais , Minerais/análise , Tamanho da Partícula , Solo/análise , Propriedades de Superfície
18.
ScientificWorldJournal ; 2013: 362854, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23737715

RESUMO

Investigating the influences of soil characteristic factors on dinoseb adsorption parameter with different statistical methods would be valuable to explicitly figure out the extent of these influences. The correlation coefficients and the direct, indirect effects of soil characteristic factors on dinoseb adsorption parameter were analyzed through bivariate correlation analysis, and path analysis. With stepwise regression analysis the factors which had little influence on the adsorption parameter were excluded. Results indicate that pH and CEC had moderate relationship and lower direct effect on dinoseb adsorption parameter due to the multicollinearity with other soil factors, and organic carbon and clay contents were found to be the most significant soil factors which affect the dinoseb adsorption process. A regression is thereby set up to explore the relationship between the dinoseb adsorption parameter and the two soil factors: the soil organic carbon and clay contents. A 92% of the variation of dinoseb sorption coefficient could be attributed to the variation of the soil organic carbon and clay contents.


Assuntos
2,4-Dinitrofenol/análogos & derivados , Poluentes do Solo/análise , Poluentes do Solo/química , Solo/análise , Solo/química , 2,4-Dinitrofenol/análise , 2,4-Dinitrofenol/química , Interpretação Estatística de Dados , Praguicidas/análise , Praguicidas/química
19.
Environ Sci Process Impacts ; 15(3): 573-8, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23738355

RESUMO

The U.S. EPA's in vitro bioaccessibility (IVBA) method 9200.1-86 defines a validated analytical procedure for the determination of lead bioaccessibility in contaminated soils. The method requires the use of a custom-fabricated extraction device that uses a heated water bath for sample incubation. In an effort to improve ease of use, increase sample throughput, and reduce equipment acquisition and maintenance costs, an alternative low-cost, commercially available extraction device capable of sample incubation via heated air and end-over-end rotation was evaluated. An intra-laboratory study was conducted to compare lead bioaccessibility values derived using the two extraction devices. IVBA values were not statistically different (α = 0.05) between the two extraction devices for any of the soils (n = 6) evaluated in this study, with an average difference in mean lead IVBA of 0.8% (s.d. = 0.5%). The commercially available extraction device was able to generate accurate lead IVBA data as compared to the U.S. EPA's expected value for a National Institute of Standards and Technology standard reference material soil. The relative percent differences between high and low IVBA values for each soil, a measure of instrument precision, were also not statistically different (α = 0.05) between the two extraction devices. The statistical agreement of lead IVBA values observed using the two extraction devices supports the use of a low-cost, commercially available extraction device as a reliable alternative to a custom-fabricated device as required by EPA method 9200.1-86.


Assuntos
Monitoramento Ambiental/instrumentação , Chumbo/análise , Poluentes do Solo/análise , Solo/análise , Monitoramento Ambiental/economia , Desenho de Equipamento , Chumbo/isolamento & purificação , Poluentes do Solo/isolamento & purificação
20.
Environ Sci Process Impacts ; 15(3): 608-16, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23738359

RESUMO

The concentrations and spatial distribution of organochlorine pesticides (OCPs) in surface soils of different altitudes (570­4656 m) from Tajikistan were determined. OCPs were detected in all samples with concentrations in the range 52.83­247.98 ng g(-1) dry weight (ng g(-1) dw). Aldrins were the most predominant compounds followed by chlordanes, hexachlorocyclohexanes (HCHs) and endosulfans, while dichlorodiphenyltrichloroethanes (DDTs) and methoxychlor were detected at much lower concentrations. Composition analysis indicated that OCPs mainly came from the atmospheric transport of historically used pesticides. OCP residues in the west and northwest parts of Tajikistan were higher than the east and the southeast due to the proximity to the potential sources and anthropogenic activity intensities around. Additionally, correlation analysis between OCPs and altitudes indicated that the more volatile pollutants, such as HCH isomers, seemed to become enriched more easily in regions with higher altitudes relative to the less volatile ones, such as DDTs.


Assuntos
Hidrocarbonetos Clorados/análise , Resíduos de Praguicidas/análise , Poluentes do Solo/análise , Solo/análise , Altitude , Monitoramento Ambiental , Tadjiquistão
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