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Search Results: 1 - 10 of 7991 matches for " Heavy Metal "
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Brassinosteroids and Plant Responses to Heavy Metal Stress. An Overview  [PDF]
Miriam Nú?ez Vázquez,Yanelis Reyes Guerrero,Lisbel Martínez González,Walfredo Torres de la Noval
Open Journal of Metal (OJMetal) , 2013, DOI: 10.4236/ojmetal.2013.32a1005
Abstract: Soil contamination with heavy metals has become a world-wide problem, leading to the loss in agricultural productivity. Plants have a remarkable ability to take up and accumulate heavy metals from their external environment and it is well known that high levels of heavy metals affect different physiological and metabolic processes. Brassinosteroids are considered as the sixth class of plant hormones and they are essential for plant growth and development. These compounds are able of inducing abiotic stress tolerance in plants. In this paper, information about brassinosteroids and plant responses to heavy metal stress is reviewed.
Brassinosteroids and Plant Responses to Heavy Metal Stress. An Overview  [PDF]
Miriam Nú?ez Vázquez, Yanelis Reyes Guerrero, Lisbel Martínez González, Walfredo Torres de la Noval
Open Journal of Metal (OJMetal) , 2013, DOI: 10.4236/ojmetal.2013.32A1005
Abstract:

Soil contamination with heavy metals has become a world-wide problem, leading to the loss in agricultural productivity. Plants have a remarkable ability to take up and accumulate heavy metals from their external environment and it is well known that high levels of heavy metals affect different physiological and metabolic processes. Brassinosteroids are considered as the sixth class of plant hormones and they are essential for plant growth and development. These compounds are able of inducing abiotic stress tolerance in plants. In this paper, information about brassinosteroids and plant responses to heavy metal stress is reviewed.

Phytoremediation Mechanisms of Heavy Metal Contaminated Soils: A Review  [PDF]
Meriem Laghlimi, Bouamar Baghdad, Hassan El Hadi, Abdelhak Bouabdli
Open Journal of Ecology (OJE) , 2015, DOI: 10.4236/oje.2015.58031
Abstract: Phytoremediation is a green emerging technology used to remove pollutants from environment components. Mechanisms used to remediate soils contaminated by heavy metal are: phytoextraction, phytostabilisation, phytovolatilization and rhizofiltration. The two first mechanisms are the most reliable. Many factors influence the choice of the suitable phytoremediation strategy for soil decontamination. It depends on soil properties, heavy metal levels and characteristics, plant species and climatic conditions. The present review discusses factors affecting heavy metals uptake by plant species, the different phytoremediation strategies of heavy metal contaminated soils and the advantages and disadvantages of phytoremediation and each of its mechanisms.
Contamination of Arsenic and Other Heavy Metals in Rhizospheric Soil  [PDF]
Khageshwar Singh Patel, Bharat Lal Sahu, Shobhana Ramteke, Nitin Kumar Jaiswal, Laura Borgese, Alessandra Gianoncelli, Elza Bontempi
American Journal of Analytical Chemistry (AJAC) , 2015, DOI: 10.4236/ajac.2015.610078
Abstract: The contamination of arsenic (As) and other heavy metal (HMs) in soil causes serious health hazard to the ecosystem. In this work, the contamination of As and other heavy metals (i.e. Ti, V, Cr, Mn, Fe, Ni, Cu, Zn and Pb) in rhizospheric soil of 14 plants of the severely As contaminated area of Central India is described. Among them, high content of As in the rhizospheric soils was observed, ranging from 0.22 to 4.60 g/kg with mean value of 1.6 ± 0.7 g/kg. The concentration variation, enrichment indices and toxicities of the metals in the soil are described.
Characterization and Application of Adsorption Material with Hematite and Polystyrene  [PDF]
Dewen He, Yutang Xiao, Dingmin Liang, Huannian Zhou, Lu Du, Lei Liu
Materials Sciences and Applications (MSA) , 2011, DOI: 10.4236/msa.2011.24027
Abstract: In this study, a three-dimensional ordered macroporous hematite was prepared using the polystyrene colloid crystal templates and characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope, and nitrogen adsorption isotherm. The as-prepared hematite shows a porous structure consisting of the macropores about 200 nm in diameter and the walls about 20 nm in thickness. The adsorption of Pb2+ and Cd2+ ions in aqueous solution by this hematite was also evaluated. At room temperature, each gram hematite adsorbs 12.5 mg of Pb2+ ions and 7.0 mg of Cd2+ ions. The results suggest that the obtained hematite should be a promising adsorbent to remove Pb2+ and Cd2+ ions, and other heavy metal ions from aqueous solution.
Contamination of Camel Milk (Heavy Metals, Organic Pollutants and Radionuclides) in Kazakhstan  [PDF]
Gaukhar Konuspayeva, Stefan Jurjanz, Gerard Loiseau, Vincent Barci, Shynar Akhmetsadykova, Aliya A. Meldebekova, Bernard Faye
Journal of Environmental Protection (JEP) , 2011, DOI: 10.4236/jep.2011.21010
Abstract: In Kazakhstan, camel breeding mainly occupies areas sometimes close to polluting industries or other sources of pollu- tion as industrial agriculture, mainly cotton. Products issued from camel farms close to these sources as camel raw milk and fermented milk (shubat), wool and meat, traditionally used by humans could be contaminated. We investigated camel raw milk and fermented milk for the content of heavy metals (lead, cadmium, zinc and copper), radionuclide and some organic pollutants (PAHs, pesticides and indicator PCBs) in samples from different regions with a priori high risk of pollution (Atyrau, Kyzylorda, South-Kazakhstan and Almaty region). In the present paper, only some milk samples presented high lead concentration (> 500 ppb). After analysis for organic pollutants, it was observed some traces of hexachlorocyclohexane, lindane, hexanchlorothalonil in milk samples from different regions. One sample was also slightly contaminated with radionuclide. These preliminary results allow establishing a first map of risk for camel farming. As the whole, South-Kazakhstan appeared the most exposed region.
Relationship Between Heavy Metal Concentrations in Bottom Sediments and the Clam, Galatea Paradoxa (Born 1778) from the Volta Estuary, Ghana  [PDF]
Hashem A Madkour, Kwasi A Obirikorang, Steve Amisah, Fred A Otchere, Daniel Adjei-Boateng
Journal of Environmental Protection (JEP) , 2011, DOI: 10.4236/jep.2011.26083
Abstract: This research was carried out at two locations, Ada and Aveglo at the Volta Estuary, Ghana to evaluate the importance of sediments as regulatory media in controlling the levels of four metals, Manganese (Mn), Zinc (Zn), Iron (Fe) and Mercury (Hg) in the tissues of the clam, Galatea paradoxa (Born 1778) and to investigate the possible relationships between the concentrations of the metals in the sediments and the clams. The clams were categorized into three size classes as follows: small (25 - 40 mm), medium (41 - 55 mm), and large (above 55 mm). To understand the possible relationships between the concentrations of the studied metals in the sediments and in the tissues of the three clam size classes, the monthly concentrations of the studied metals were graphed and subjected to Pearson correlation analyses (p < 0.05) to identify metal accumulation patterns and determine whether or not positive relationship patterns existed between the concentrations in the clams and sediment samples. The correlation revealed no simple linear relationships between the concentrations of four heavy metals in the clam tissues and the sediments at the two sampling stations although some distinct trends were observed. Mn concentrations in the clams and sediments from the two stations showed some clear positive relationship patterns with some increments in monthly sediment concentrations resulting in increments in clam tissue concentrations. This relationship though, was not too clear-cut.
The Quality and Health Implications of Urban Irrigation Water Used for Vegetable Production in the Accra Metropolis  [PDF]
Mark O. Akrong, Joseph A. Ampofo, Seth K. A. Danso
Journal of Environmental Protection (JEP) , 2012, DOI: 10.4236/jep.2012.311167
Abstract: The quality of irrigation water from different sources used by urban farmers in the Accra Metropolis was investigated. These were, tap water stored in dugout, surface water (from stream) and wastewater in drains. The samples were analysed for their bacteriological, physical and chemical qualities using standard methods. Analytical Profile Index (API) identification system was used to characterize and identify the bacterial species isolated in the samples. The results showed that heavy metal concentrations in the samples were within the FAO/WHO recommended limits for irrigation. The concentrations of highly toxic Lead and Cadmium were even below detection limit. Total and faecal coliform bacteria loads in all three potential irrigation water sources were above the WHO recommended limit for irrigation. Different bacteria species belonging to seven genera were identified in the three irrigation water sources. These included Citrobacter, Chryseomonas, Enterobacter, Klebseila, Proteus, Providencia, Pseudomonas. Generally, the most dominant bacterial species were Pseudomonas aeruginosa and Chryseomonas luteola. Some of these bacteria spp. can pose a health threat to farmers especially those who have challenges with their health and immune system. For example, infection with some of the bacteria species such as Pseudomonas aeruginosa in patients with cystic fibrosis is known to be deadly over periods of time.
Metal Concentration in Fresh Water Fish Organs  [PDF]
Krishnappa Venkatesha Raju,Rayasamudra Kalegowda Somashekar,Konehally Lakshmaiah Prakash
Open Journal of Metal (OJMetal) , 2013, DOI: 10.4236/ojmetal.2013.32004
Abstract: This study was conducted during March to May of 2010 dry season, giving prime thrust to determine the metal concentrations in commercial fish species of Catla catla and Labeo rohita, collected from various points along the river Cauvery. The liver, gill and muscle tissues of fish were analyzed for Fe, Pb, Zn, Ni, Mn, Cu, Cr and Cd using Atomic Absorption Spectrophotometry (AAS-model: 6300). The Catla catla has shown more accumulation potency for all the metals than Labeo rohita. The liver in both fish species has better accretion capacity compared to gill and muscle and the same was noticed by bioaccumulation factor. The results of bioaccumulation factor were in the order of Ni > Zn > Cu > Mn > Fe > Cr > Pb > Cd. Elevated trend was noticed among the essential metals and decreased trend among the nonessential metals were observed in both fish species.
Changes in Activity of Three Sulfurtransferases in Response to Exposure to Cadmium, Lead and Mercury Ions  [PDF]
Marta Kaczor-Kamińska, Piotr Sura, Maria Wróbel
Journal of Environmental Protection (JEP) , 2013, DOI: 10.4236/jep.2013.46A003
Abstract:

Cadmium, lead and mercury are environmentally persistent toxicants that affect tissues and cellular components or exert an effect on generation of reactive oxygen species causing a decreased level of available antioxidant reserves. Sulfurtransferases are enzymes that are widespread in nature. Rhodanese, 3-mercaptopyruvate sulfurtransferase and γ-cystathionase play an important role in the metabolism of L-cysteine. Heavy metal ions can bind to -SH groups of cysteine residues in their active sites and, therefore, decrease the activity of these enzymes and result in changes in the level of sulfane sulfur-containing compounds, products of L-cysteine desulfuration. Changes in the activity of sulfurtransferases were investigated in the kidneys, heart, brain, liver and skeletal muscle of Marsh frogs (Pelophylax ridibundus) after 10 days of exposure to Pb(NO3)2 at the concentration of 28 mg/L and CdCl2 at the concentration of 40 mg or 80 mg/L, and in Xenopus laevies tissues after 7 and 14 days of exposure to HgCl2 at the concentration of 1.353 mg/L. The investigated heavy metal ions have a tendency to inhibit the activity of sulfurtransferases and decrease the level of glutathione, what can result in oxidative stress and oxidation of cysteine -SH groups to -SOH. This reversible oxidation and reduction of these redox sensitive groups can play a role in defenses against oxidative stress. Based on the presented results, one can surmise that also the expression of the three sulfurtransferases depends on heavy metal ions and/or some

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