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Genetic Analysis of Black Spruce (Picea mariana) Populations from Dry and Wet Areas of a Metal-Contaminated Region in Ontario (Canada) Texte intégral
2011
Dobrzeniecka, Sylwia | Nkongolo, Kabwe K. | Michael, Paul | Mehes-Smith, Melanie | Beckett, Peter
Genetic variation and genetic structure of black spruce (Picea mariana L.) populations growing in wet land (lowlands) and dry lands (uplands) with different levels of metal contaminations were analyzed using ISSR. Polymorphic loci (P%) ranged from 65% to 90% with a mean of 75%. Nei’s gene diversity (h) varied from 0.264 to 0.359 with a mean of 0.310, and Shannon’s index (I) ranged from 0.381 to 0.524 with a mean of 0.449. The level of genetic variation was higher in populations from wet lands than those from dry lands. Variation within populations accounts for most of total genetic variation. The genetic distance among the black spruce (P. mariana) populations ranged from 0.171 to 0.351. The present study indicates that genetic variation and long-term exposure to metals (more than 30Â years) are not associated. Cytological analysis of black spruce seeds from metal-contaminated and -uncontaminated areas showed normal mitotic behavior during prophase, metaphase, anaphase, and telophase.
Afficher plus [+] Moins [-]Equilibrium and Kinetic Characteristic of Adsorption of Cu2+, Pb 2+ on a Novel Anionic Starch Microspheres Texte intégral
2011
Yang, YaTi | Wei, XiuZhi | Wan, JuanMin | Meng, ZhaoFu
Neutral starch microspheres (NSMs) were synthesized with epichlorohydrin as the cross-linking agent from soluble starch by inverse microemulsion method. Anionic starch microspheres (ASMs) were prepared from NSMs by the secondary polymerization with chloroacetic acid as the anionic etherifying agent. Scanning electron microscopy (SEM) revealed that microspheres had good sphericity and fine dispersibility, and the average particle size was about 75 μm. The adsorption procedure of Cu2+, Pb2+ on ASMs was carried out by batch experiments, Langmuir and Freundlich adsorption models were applied to describe the experimental isotherms, the adsorption equilibrium data were found to fit the Langmuir and Freundlich isotherm model, the Freundlich isotherm was more adequate than the Langmuir isotherm in simulating the adsorption isotherm of Cu2+,the adsorption of Cu2+, Pb2+ on ASMs was a spontaneous, the isosteric heat of adsorption at different adsorption levels was always negative and indicative of an exothermic process. The pseudo first- and second-order kinetic models were used to describe the kinetic data, and the rate constants were evaluated. The experimental data fitted well to the second-order kinetic model, which indicated that the chemical sorption was the rate-limiting step, instead of mass transfer.
Afficher plus [+] Moins [-]Using Seven Types of GM (1, 1) Model to Forecast Hourly Particulate Matter Concentration in Banciao City of Taiwan Texte intégral
2011
Pai, Tzu-Yi | Ho, Ching-Lin | Chen, Shyh-Wei | Lo, Huang-Mu | Sung, Pao-Jui | Lin, Shuwen | Lai, Wei-Jia | Tseng, Shih-Chi | Ciou, Shu-Ping | Kuo, Jui-Ling | Kao, Jing-Tang
In this study, seven types of first-order and one-variable grey differential equation model (abbreviated as GM (1, 1) model) were used to predict hourly particulate matter (PM) including PM10 and PM2.5 concentrations in Banciao City of Taiwan. Their prediction performance was also compared. The results indicated that the minimum mean absolute percentage error (MAPE), mean squared error (MSE), root mean squared error (RMSE), and maximum correlation coefficient (R) was 14.10%, 25.62, 5.06, and 0.96, respectively, when predicting PM10. When predicting PM2.5, the minimum MAPE, MSE, RMSE, and maximum R value of 15.24%, 11.57, 3.40, and 0.93, respectively, could be achieved. All statistical values revealed that the predicting performance of GM (1, 1, x (0)), GM (1, 1, a), and GM (1, 1, b) outperformed other GM (1, 1) models. According to the results, it revealed that GM (1, 1) GM (1, 1) was an efficiently early warning tool for providing PM information to the inhabitants.
Afficher plus [+] Moins [-]The Fate of Polymeric Quaternary Ammonium Salts from Cosmetics in Wastewater Treatment Plants Texte intégral
2011
Cumming, Janet | Hawker, Darryl | Chapman, Heather | Nugent, Kerry
Polymeric quaternary ammonium salts or polyquaterniums used in cosmetics have been categorised as chemicals of concern in wastewater treatment plant (WWTP) effluent largely on the basis of emerging evidence of toxicity to aquatic organisms. However, little is known of their environmental fate and behaviour due to analytical difficulties with sample matrices. Their properties of negligible volatilisation and biotransformation enable the common fugacity-based model for WWTPs to be simplified to an equifugacity one where a compound has the same fugacity regardless of phase or position in the plant’s process train. To gain an appreciation of their fate, this approach is used to calculate removal efficiencies in WWTPs. These can be determined without calculating phase-specific fugacity capacity constants. To predict effluent concentrations however, an aquivalence approach is necessary because of the lack of volatility of these compounds. Using previously measured biosolids/water distribution coefficients for common polyquaterniums found in cosmetics and flow rate data from a local municipal WWTP in South East Queensland, Australia, the removal efficiencies of the polyquaterniums of interest are predicted to be only 25% or less, meaning relatively little attenuation in the WWTP. A Monte Carlo simulation shows a roughly normal distribution in the model output of polyquaternium removal efficiency, with a mean and mode of approximately 26%. A sensitivity analysis confirms that the model output is most sensitive to the magnitude of the biosolids/water distribution coefficient compound and shows WWTP data such as biosolids removal efficiency have only a relatively small effect.
Afficher plus [+] Moins [-]Growth and Lead Accumulation Capacity of Lemna minor and Spirodela polyrhiza (Lemnaceae): Interactions with Nutrient Enrichment Texte intégral
2011
Leblebici, Zeliha | Aksoy, A (Ahmet)
A study to understand the biological effects of samples prepared with lead and the effects of lead were conducted on Lemna minor L. and Spirodela polyrhiza (L.) Schleid. This study was intended to test the hypothesis that nutrient enrichment (P, NO ₃ ⁻ -N and SO ₄ ²⁻ ) enhances the metal tolerance of floating macrophytes. The plants were exposed to Pb concentrations 0, 1, 5, 10, 25, and 50 mg l⁻¹ for a period of 1, 3, 5, and 7 days. L. minor accumulated 561 mg g⁻¹ dry weight (dw) Pb, and S. polyrhiza accumulated 330 mg g⁻¹ dw Pb after 7 days, whereas in the groups enriched with nutrients, L. minor accumulated 128.7 mg g⁻¹ Pb and S. polyrhiza accumulated 68.7 mg g⁻¹ dw Pb after 7 days. Relative growth rates and photosynthetic pigments (chlorophyll a, b, and carotenoid) were measured in L. minor and S. polyrhiza exposed to different Pb concentrations under laboratory conditions. Relative growth rates were negatively correlated with metal exposure, but nutrient addition was found to suppress this effect. Photosynthetic pigment levels were found negatively correlated with metal exposure, and nutrient addition attenuated chlorophyll decrease in response to metal exposure. Metal and nutrient concentration in water decreased throughout the experiments. The study concluded that nutrient enrichment increases the tolerance of L. minor and S. polyrhiza to metals, that L. minor and S. polyrhiza are suitable candidates for the phytoremediation of low-level lead pollution, and that L. minor was more effective in extracting lead than was S. polyrhiza.
Afficher plus [+] Moins [-]Tracing Organic Footprints from Industrial Effluent Discharge in Recalcitrant Riverine Chromophoric Dissolved Organic Matter Texte intégral
2011
Borisover, Mikhail | Laor, Yael | Saadi, Ibrahim | Lado, Marcos | Bukhanovsky, Nadezhda
Excitation–emission matrix fluorescence spectroscopy, combined with parallel factor analysis and measurements of UV absorption and dissolved organic carbon (DOC) concentrations, was used to trace the footprints of industrial effluents discharged into the lower Kishon River (Israel). The lower Kishon River typifies streams that are affected by seawater tidal intrusion and represents an extreme case of severe long-term pollution caused mainly by a variety of industrial effluents. The industrial effluents may contribute about 90%, in terms of biochemical oxygen demand, of the total organic carbon discharged into the lower Kishon River. Water samples were collected along the river, including the points of effluent discharge from industrial plants, between November 2005 and September 2006. Two types of fluorescent components characterized the fluorescence of the lower Kishon River water: component I corresponded to humic-like matter and component II spectrally resembled material known to be associated with biological productivity, but different from typical tryptophan-like fluorophore. These fluorescent components and other substances that absorbed light at 254 nm contributed to the DOC pool that resisted riverine microbial degradation under laboratory conditions, and that constitutes up to 70% of the overall riverine DOC. The variations in DOC concentration, absorbance at 254 nm, and concentration of humic-like matter (characterized by component I) correlated with the distance from the sea and the water electrical conductivity, and were linked to seawater tidal intrusion. The increased concentration of component II, as well as its enlarged fraction in the overall riverine DOC pool, was found to be associated with the location of major inputs of the industrial effluents. These findings support the use of this fluorescent component as an indicator of industrial pollution in such severely contaminated riverine systems.
Afficher plus [+] Moins [-]Mixing of Acid Rock Drainage with Alkaline Ash Leachates—Fate and Immobilisation of Trace Elements Texte intégral
2011
Bäckström, Mattias | Sartz, Lotta
Acid rock drainage (ARD) often contains ferrous iron, sulphate and high concentrations of trace elements detrimental to the environment. Future costs will be enormous if the problem is not treated today. Simple and cost-effective methods for remediation of historical mine sites are therefore desired. In this study, three mine waters were mixed with alkaline ash leachates, and the fate of trace elements from both the mine waters (Cd, Cu, Pb, Zn, Ni and Co) and the ash leachates (Cr and Mo) was studied. Addition of ash water precipitates hydrous ferric oxides (HFO) and hydrous aluminium oxides (HAO) induced trace element sorption and coprecipitation. Composition of the formed HFO/HAO mix determines efficiency of the sorption and the relative order of sorption for different trace elements. Sorption occurred much earlier (often one pH unit or more) in a system with high iron concentrations compared to systems with lower iron concentrations. Removal of cadmium and zinc was low, below pH 8, if the amount of precipitates was low. Using ash for generation of alkaline water may be a problem with regard to chromium and molybdenum. This study shows that it is possible to avoid problems with molybdenum by keeping the final pH around 7, and chromium(VI) from the ash water will be reduced into chromium(III) and precipitated as the hydroxide in the presence of iron(II). Results imply that it is possible to also use fly ashes in alkaline leach beds in order to neutralize ARD followed by precipitation and sorption of trace elements.
Afficher plus [+] Moins [-]Presence of Pharmaceuticals and Hormones in Waters from Sewage Treatment Plants Texte intégral
2011
Pedrouzo, Marta | Borrull, Francesc | Pocurull, Eva | Marcé, Rosa Maria
This paper describes the presence of 33 pharmaceuticals and hormones in waters from two sewage treatment plants (STPs) situated in Catalonia, in northeastern Spain. The target compounds were one psychoactive stimulant, one antiepileptic, four analgesics and non-steroidal anti-inflammatories, one lipid regulators, two anti-ulcer agents, nine antibiotics (sulfonamides and macrolides), two beta-blockers, two metabolites, and 11 hormones (free and conjugates). The determination was performed using liquid chromatography coupled to tandem mass spectrometry after enrichment by solid-phase extraction with Oasis HLB sorbent. Most of the pharmaceuticals were found in both influent and effluent samples from the two STPs. The most frequently detected were caffeine, acetaminophen, carbamazepine, diclofenac, ibuprofen, naproxen, sulfamethoxazole, sulfapyridine, sulfathiazole, ranitidine, omeprazole, estrone 3-sulfate, and estradiol 17-glucuronide. Specifically, the highest concentrations found in influents were 19,850Â ng/L (acetaminophen), 9,945Â ng/L (caffeine), 4,215Â ng/L (ibuprofen), 5,695Â ng/L (sulfamethoxazole), and 5,140Â ng/L (sulfathiazole). Most of the pharmaceuticals present in influent waters were found in effluents at lower concentrations. The highest concentrations in effluents were 970Â ng/L (caffeine), 670Â ng/L (sulfamethoxazole), 510Â ng/L (bezafibrate), and 1,032Â ng/L (diclofenac).
Afficher plus [+] Moins [-]Tannin-Based Coagulants in the Depuration of Textile Wastewater Effluents: Elimination of Anthraquinonic Dyes Texte intégral
2011
Beltrán-Heredia, Jesus | Sánchez-Martín, Jesus | Jiménez-Giles, Mercedes
Two tannin-based coagulants have been tested on anthraquinonic dye elimination from aqueous solutions. Acquapol S5T, derived from Acacia mearnsii de Wild, and Silvafloc, derived from Schinopsis balansae, were found to be excellent agents in the destabilization of Alizarin Violet 3R dye and its elimination through coagulation from textile effluents. Both coagulants showed that high affinity to the dye molecule in a wide pH range and q values reaches significant levels (up to 0.5 mg mg − 1) with reasonable low coagulant doses. Dye–coagulant system presented a consistent behavior if studied under the statistical perspective of a design of experiments, where initial dye concentration and coagulant dose were the operating variables. Finally, both coagulants seemed to follow a predictable theoretical model under the Langmuir hypothesis with an accurate adjusted r 2 coefficient above 0.9.
Afficher plus [+] Moins [-]Mineralization of Monomeric Components of Biodegradable Plastics in Preconditioned and Enriched Sandy Loam Soil Under Laboratory Conditions Texte intégral
2011
Siotto, Michela | Tosin, Maurizio | Degli Innocenti, Francesco | Mezzanotte, Valeria
In the last 20 years, a new generation of materials was developed: the biodegradable plastics. They reduce the accumulation of plastic in the environment and the cost of waste management because they can be fed in composting plants or, if used in agriculture (mulch films), they are applied to the soil and left there. Ten monomers were chosen among the most used in the synthesis of biodegradable polymers (1,2-ethanediol, 1,4-butanediol, 1,6-hexanediol, adipic acid, azelaic acid, sebacic acid, terephthalic acid, glucose, lactic acid, and succinic acid) and tested according to ASTM 5988-96 (a standard test method for determining aerobic biodegradation in soil of plastic materials measuring the carbon dioxide evolution). Two sandy loam soils, collected in two different sites in Italy, were used to evaluate the mineralization rate of the monomers. Four tests (two replicates each) were carried out for 27–39 days. Experimental data show no relevant differences in the respirations of the two soils and in the carbon dioxide productions of the tested monomers. The final mineralization percent was 42–45% for glucose, succinic, and lactic acid and 50–56% for the other monomers.
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