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Pollutant Concentrations in the Rime and Fog Water at the Milesovka Observatory Texto completo
2009
Fisak, Jaroslav | Tesar, Miroslav | Fottova, Daniela
The paper summarizes results of chemical analyses of fog and rime water samples. The samples were collected at Milesovka, the Czech meteorological observatory. The input data set contains the samples acquired during 234 fogs and 14 rime events. The fog and rime samples were collected in the period of 2000-2004. Methods employed for sampling fog and rime water and differences in the pollutant concentrations are described. The following components were analyzed: conductivity, acidity (pH), cations Na⁺, K⁺, NH₄ ⁺, Mg²⁺, Ca²⁺, and anions F⁻, Cl⁻, NO₃ ⁻, SO₄ ²⁻. The attention was exclusively devoted to the precipitation originating in fogs (no falling precipitation particles were considered). Differences in the relative content of selected ions in the annual average samples of rime and fog are presented together with their absolute values. The importance of rime contributions to total precipitation amounts is demonstrated by maximum values of the rime weight detected at the Milesovka Observatory. The absolute maximum of 52.3 kg m⁻² was registered at Milesovka Mt. on December 28, 2002.
Mostrar más [+] Menos [-]Reuse of Domestic Greywater for the Irrigation of Food Crops Texto completo
2009
Finley, Sara | Barrington, Suzelle | Lyew, Darwin
As global water resources decline, reuse of domestic greywater for the irrigation of home gardens is quickly becoming widespread in many parts of the world. However, the sanitary implications of reusing greywater to water edible crops remain uncertain. This study examined the benefits and risks associated with domestic greywater reuse for the purposes of vegetable garden irrigation. Untreated (settled only) and treated (settling and slow sand filtration) greywater collected from a family home was analyzed for basic water quality parameters over a period of 8 weeks. During that time, both greywaters were used to irrigate individually potted plots of lettuce, carrots, and peppers in a greenhouse. Tap water was used as control. Upon maturity, plants were harvested and the edible portions tested for fecal coliforms and fecal streptococci, common indicators for the presence of pathogenic microorganisms. Heavy metals were not detected in the greywater, but both fecal coliforms and fecal streptococci were present in high levels, averaging 4 x 10⁵/100 mL and 2,000/100 mL of greywater, respectively. Despite these high counts, no significant difference in contamination levels was observed between crops irrigated with tap water, untreated greywater, and treated greywater. Fecal coliform levels were highest in carrots and fecal streptococcus levels were highest on lettuce leaves. However, contamination levels for all crops were low and do not represent a significant health risk. Plant growth and productivity were unaffected by water quality, owing to the low N, P, and K levels of the greywater. These results reinforce the potential of domestic greywater as an alternative irrigation source.
Mostrar más [+] Menos [-]Adsorption of Lead and Cadmium from Aqueous Solution by Using Almond Shells Texto completo
2009
Mehrasbi, Mohammad Reza | Farahmandkia, Zohreh | Taghibeigloo, Bahareh | Taromi, Azra
The potential of almond shells was assessed for adsorption of heavy metal ions such as Pb²⁺ and Cd²⁺ from aqueous solution. Almond shells were pretreated separately with 0.4 mol/L NaOH, 0.4 mol/L HNO₃, and distilled water and their adsorption abilities were compared. Batch adsorption experiments were carried out as a function of the initial ion concentration, pH, and adsorbent dosage. Adsorption isotherms of metal ions on adsorbents were determined and correlated with common isotherm equations such as Langmuir, Freundlich, and BET models. The alkali-modified almond shells had adsorption capacities for Pb²⁺ from 2 to 9 mg/g and for Cd²⁺ from 2 to 7 mg/g, which was much higher than acid- and water-pretreated adsorbents. Experimental results showed that the best pH for adsorption was 5-6 and the adsorption values decreased with lowering pH. Isotherm models indicated the best fit for Langmuir model for alkali-modified almond shells. In comparing the parameters of the models, it was observed that the affinity of almond shells for adsorption of lead is stronger than affinity for adsorption of cadmium.
Mostrar más [+] Menos [-]Evaluation of Poultry Litter Amendment to Agricultural Soils: Leaching Losses and Partitioning of Trace Elements in Collard Greens Texto completo
2009
Paramacivam, Aru (Aruṇakiri) | Richards, Karen A. | Alva, A. K. | Richards, Asha M. | Sajwan, K. S. | Jayaraman, K. | Heanacho, A. | Afolabi, J.
Leaching of trace metals and greenhouse plant growth (Collard greens; Brassica oleracea var. acephala) response studies were conducted in two types of soils with contrasting characteristics amended with varying rates (0 to 24.70 Mg ha⁻¹) of poultry litter (PL) or 1:1 mixture of PL and fly ash (FA). Leaching of Cr, Zn, Cd, Cu, and Pb from soils amended with PL or PL + FA (1:1) increased with increasing rates of amendment. Leaching losses were greater from coarse-textured soil compared to that from medium-textured soil. Crop performance study indicated that growth as well as trace elements concentrations increased with increasing rates of amendments only up to 12.35 Mg ha⁻¹. Trace element concentrations in plant parts were greater in plants grown in Candler fine sand (CFS) compared to that grown in Ogeechee loamy sand (OLS). Trace element concentrations were greater in the above ground plant parts (leaf and stem) than those in roots. This study demonstrated beneficial effects of PL or mixture of PL + FA amendments to soils at rates not exceeding 4.94 Mg ha⁻¹. Further field studies are recommended to evaluate the long-term impact of using poultry litter and fly ash on plant growth and tissue trace metal concentration as well as environmental impact.
Mostrar más [+] Menos [-]Anthropogenic Heavy Metal Pollution in the Surficial Sediments of the Keratsini Harbor, Saronikos Gulf, Greece Texto completo
2009
Galanopoulou, Stavroula | Vgenopoulos, Andreas | Conispoliatis, Nikolaos
The contents of ten elements [Cd, Pb, W, Zn, Mn, As, Se, Cr, Cu, and organic carbon (Corg)] have been determined in the surficial sediments of Keratsini harbor, Saronikos Gulf, Greece. The contamination of the sediments was assessed on the basis of geoaccumulation index and to corresponding sediment quality guidelines (SQGs) effects range low/effects range median. The results revealed highly elevated Cd, Pb, W, Zn, As, Se, Cr, Cu, and Corg values (Cd, 190-1,763 mg kg⁻¹; Pb, 521-1,263 mg kg⁻¹; W, 38-100 mg kg⁻¹; Zn, 409-6,725 mg kg⁻¹; Mn, 95-1,101 mg kg⁻¹; As, not detectable-1,813 mg kg⁻¹; Se, not detectable-58 mg kg⁻¹; Cr, 264-860 mg kg⁻¹; Cu, 195-518 mg kg⁻¹; and Corg, 0.69-4.41%). The enrichment of metals in the sediments results from the contribution of the central Athens sewage outfall through which the waste of the Attica basin ends up in Keratsini harbor as well as from industrial and ship contaminants.
Mostrar más [+] Menos [-]Model Analysis of PM₁₀ Concentration Variations Over a Mineral Products Industrial Area in Saraburi, Thailand Texto completo
2009
Pimonsree, Sittichai | Wongwises, Prungchan | Pan-Aram, Rudklao | Zhang, Meigen
Air pollution associated with particulate matters is a serious problem in the mineral products industrial area (MPIA) in Saraburi, central Thailand. PM₁₀ concentrations monitored at Nah Phra Laan station located in the MPIA show that PM₁₀ levels exhibit strong seasonal variations; the number of days in 2005 that PM₁₀ concentrations exceeded the daily National Ambient Air Quality Standard of 120 μg/m³ were 58%, 29%, and 12% in the winter, rainy, and summer seasons, respectively. In this paper, the Hybrid Particle And Concentration Transport (HYPACT) model with meteorological fields from the Regional Atmospheric Modeling System (RAMS) was applied to Saraburi to investigate the impacts of meteorological parameters upon seasonal variations in PM₁₀ concentration. Analysis of model results shows that daily average PM₁₀ concentrations exceeding 200 μg/m³ are found in the downwind direction of emission sources and their horizontal gradients are strong. Hourly PM₁₀ concentrations exhibit obvious diurnal variation with maximum values in wintertime at around 2000-2100 local standard time in association with low ventilation with light wind speed and weak vertical mixing, while in the rainy season, they are generally higher in the daytime than in the nighttime, as that mixing height in cloudy days is low in daytime whereas emission rates are high during working time.
Mostrar más [+] Menos [-]Relationship Between pH and Stream Water Total Mercury Concentrations in Shenandoah National Park Texto completo
2009
Moore, C. W. | Cosby, B. J. | Galloway, J. N. | Castro, M. S.
The purpose of this study was to gather information on the spatial and temporal variation of stream water total mercury concentrations ([THg]) and to test the hypothesis that stream water [THg] increases as stream pH decreases in the Shenandoah National Park (SNP). We based our hypothesis on studies in lakes that found mercury methylation increases with decreasing pH, and studies in streams that found total mercury and other trace metal concentrations increase with decreasing pH. Stream water was collected at baseflow in SNP in April, July, and October 2005 and February 2006. Contrary to our hypothesis, stream water [THg] decreased with decreasing pH and acid neutralizing capacity. In SNP, stream pH and acid neutralizing capacity are strongly influenced by bedrock geology. We found that bedrock also influences stream water [THg]. Streams on basaltic bedrock had higher [THg] (0.648 ng L⁻¹ ± 0.39) than streams on siliciclastic bedrock (0.301 ng L⁻¹ ± 0.10) and streams on granitic bedrock (0.522 ng L⁻¹ ± 0.06). The higher pH streams on basaltic bedrock had the highest [THg]. The variation in stream water [THg] occurred despite no known variation in wet deposition of mercury across the SNP. The findings of this study indicate that the SNP can be an important area for mercury research with significant variations in mercury concentrations across the park.
Mostrar más [+] Menos [-]Relation Between pH and Desorption of Cu, Cr, Zn, and Pb from Industrially Polluted Soils Texto completo
2009
Ottosen, Lisbeth M. | Hansen, Henrik K. | Jensen, Pernille E.
Desorption of Cu, Cr, Pb, and Zn from industrially polluted soils as a result of acidification is in focus. The eight soils of the investigation vary greatly in composition and heavy metal concentration/combination. Three soils had elevated concentrations of Cu, Pb, and Zn; regardless of pollution level, pollution origin, and soil type, the order for desorption as pH decreased was Zn > Cu > Pb. Turning to a single heavy metal in different soils, there was a huge difference in the pH at which the major desorption started. The variation was most significant for Pb where, e.g., less than 10% was desorbed at pH 2.5 from one soil, whereas in another soil 60% Pb was desorbed at this pH. Sequential extraction was made and the soils in which a high percentage of Pb was found in the residual phase (adsorbed strongest) was also the soils where less Pb was desorbed at low pH in the desorption experiments. It was evident that Cu, Pb, and Zn started to desorb at a higher pH from calcareous soils than from soils with low carbonate content. The mechanism responsible for this is co-precipitation of heavy metals in the carbonates. When the carbonates are dissolved at a relatively high pH of about 5, the co-precipitated heavy metals are released. The sequential extraction pattern for Cr differed generally much from the other heavy metals since the majority of Cr was extracted in the last two steps. Cr was also the heavy metal that desorbed the least at high acidification.
Mostrar más [+] Menos [-]Toxic Elements in Aquatic Sediments: Distinguishing Natural Variability from Anthropogenic Effects Texto completo
2009
Hou, Aixin | DeLaune, R. D. | Tan, MeiHuey | Reams, Margaret | Laws, Edward
Regressions of aluminum against potentially toxic elements in the sediments of freshwater aquatic systems in Louisiana were used to distinguish natural variability from anthropogenic pollution when elemental concentrations exceeded screening effects levels. The data were analyzed using geometric mean model II regression methods to minimize, insofar as possible, bias that would have resulted from the use of model I regression. Most cadmium concentrations exceeded the threshold effects level, but there was no evidence of an anthropogenic impact. In Bayou Trepagnier, high concentrations of Cr, Cu, Pb, Ni, and Zn appeared to reflect anthropogenic pollution from a petrochemical facility. In Capitol Lake, high Pb concentrations were clearly associated with anthropogenic impacts, presumably from street runoff. Concentrations of potentially toxic elements varied naturally by as much as two orders of magnitude; hence it was important to filter out natural variability in order to identify anthropogenic effects. The aluminum content of the sediment accounted for more than 50% of natural variability in most cases. Because model I regression systematically underestimates the magnitude of the slope of the regression line when the independent variable is not under the control of the investigator, use of model II regression methods in this application is necessary to facilitate hypothesis testing and to avoid incorrectly associating naturally high elemental concentrations with human impacts.
Mostrar más [+] Menos [-]Trace Element Uptake by Mitchell Grasses Grown on Mine Wastes, Cannington Ag-Pb-Zn Mine, Australia: Implications for Mined Land Reclamation Texto completo
2009
Lottermoser, B. G. | Munksgaard, N. C. | Daniell, M.
This study was conducted to determine the metal (Ag, Al, As, Cd, Co, Cu, Fe, Mn, Ni, Pb, Sb, Zn) tolerance and uptake of Mitchell grasses when grown on waste rocks and tailings of a base metal mine, Australia. The objective of conducting such phytoremediation studies was to gain data relating to the implementation and effectiveness of capping and revegetation strategies for mine waste repositories in regions of native grasslands. Pot trials demonstrate that Mitchell grasses are metal tolerant and have the ability to accumulate significant concentrations of metals (Pb, Zn) into their above-ground biomass. Concentrations of metals in Mitchell grasses were evaluated in terms of maximum allowable dietary levels in livestock. The pot trial project revealed that if Mitchell grasses were to be used for mined land reclamation and were grown on tailings, the grasses could potentially accumulate large quantities of Zn in their tissue, potentially causing harmful effects on animals feeding on them. Hence, it is undesirable that Mitchell grasses are grown on and their root system come in contact with tailings with elevated level of Zn. Otherwise, the species may accumulate phyto- and zootoxic concentrations of Zn. The metal tolerance, the tendency to accumulate metals in the above-ground biomass and the significant root penetration depth of Mitchell grasses have implications for the design of tailings storage facilities. Capping of waste repositories, containing elevated metal concentrations and using a cover system without capillary breaks, clay layers or alternative strategies, may not be sustainable in the long term. The application of phosphate amendments to tailings may represent an alternative strategy to limit the uptake of metals by Mitchell grasses. The pot trials prove that the addition of phosphate to mine wastes decreases the bio-availability of metals in these materials and reduces the Pb and Zn concentration in Mitchell grasses growing on them. Thus, the addition of phosphate amendments to the top layers of metalliferous mine wastes may represent an alternative waste management strategy.
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