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Effects of Vegetation, Season and Temperature on the Removal of Pollutants in Experimental Floating Treatment Wetlands Полный текст
2010
The research and interest towards the use of constructed floating wetlands for (waste)water treatment is emerging as more treatment opportunities are marked out, and the technique is applied more often. To evaluate the effect of a floating macrophyte mat and the influence of temperature and season on physico-chemical changes and removal, two constructed floating wetlands (CFWs), including a floating macrophyte mat, and a control, without emergent vegetation, were built. Raw domestic wastewater from a wastewater treatment plant was added on day 0. Removal of total nitrogen, NH₄-N, NO₃-N, P, chemical oxygen demand (COD), total organic carbon and heavy metals (Cu, Fe, Mn, Ni, Pb and Zn) was studied during 17 batch-fed testing periods with a retention time of 11 days (February-March 2007 and August 2007-September 2008). In general, the CFWs performed better than the control. Average removal efficiencies for NH₄-N, total nitrogen, P and COD were respectively 35%, 42%, 22% and 53% for the CFWs, and 3%, 15%, 6% and 33% for the control. The pH was significantly lower in the CFWs (7.08 ± 0.21) than in the control (7.48 ± 0.26) after 11 days. The removal efficiencies of NH₄-N, total nitrogen and COD were significantly higher in the CFWs as the presence of the floating macrophyte mat influenced positively their removal. Total nitrogen, NH₄-N and P removal was significantly influenced by temperature with the highest removal between 5°C and 15°C. At lower and higher temperatures, removal relapsed. In general, temperature seemed to be the steering factor rather than season. The presence of the floating macrophyte mat restrained the increase of the water temperature when air temperature was >15°C. Although the mat hampered oxygen diffusion from the air towards the water column, the redox potential measured in the rootmat was higher than the value obtained in the control at the same depth, indicating that the release of oxygen from the roots could stimulate oxygen consuming reactions within the root mat, and root oxygen release was higher than oxygen diffusion from the air.
Показать больше [+] Меньше [-]Trace Elements in Plankton, Benthic Organisms, and Forage Fish of Lake Moreno, Northern Patagonia, Argentina Полный текст
2010
Arribére, Maria A. | Campbell, Linda M. | Rizzo, Andrea P. | Arcagni, Marina | Revenga Sánchez, Jorge | Ribeiro Guevara, Sergio
The Northern Patagonian Andean range shared by Chile and Argentina has numerous glacial oligotrophic lakes protected in a series of National Parks. Recent baseline surveys indicated that concentrations in muscle and liver tissues from various fish species from across Nahuel Huapi and Los Alerces National Parks in Argentina were comparable or higher than similar fish species from other parts of the world. As a result, Lake Moreno, in Nahuel Huapi National Park, was chosen to investigate multiple element sinks, trends, and transfer in a representative Patagonia aquatic food web. The metals and metalloids Ag, As, Ba, Br, Cs, Co, Cr, Fe, Hg, K, Na, Rb, Se, and Zn were analyzed in three size plankton fractions, submerged macrophytes, biofilm, insect larvae, amphipods, decapods, gastropods (snails), annelids (earthworms), and forage fish. Except for nanoplankton (10-53 μm; small-celled algae, rotifers) and microplankton (53-200 μm; larger algae, ciliates, zooplankton nauplii), which share elemental compositional similarities, each taxon category had its own distinctive compositional pattern, revealed by principal component analysis. Nano- and microplankton tend to be relatively elevated in some metals, including As, Co, Cr, Fe, Hg, Zn, and Rb, followed by biofilm. Shredder-scrapper Trichoptera (caddisflies) have higher concentration of most of the studied elements than other insect larvae taxa, especially carnivorous Odonata (Anisoptera, dragonflies), which were associated with lower elemental contents. Those trends point to an overall tendency for biodiminishing element concentrations with trophic level in the benthos of Lake Moreno.
Показать больше [+] Меньше [-]Physiological Response of Daphnia magna to Linear Anionic Polyacrylamide: Ecological Implications for Receiving Waters Полный текст
2010
Acharya, Kumud | Schulman, Candi | Young, Michael H.
Linear anionic polyacrylamide (LA-PAM) is being considered as a soil amendment to reduce seepage and infiltration in unlined earthen canals. While polyacrylamides have been extensively used for potable water treatment, dewatering sewage sludge, coal and mine processing, paper manufacturing, and agriculture, little is known about its ecological impact to aquatic ecosystems. Acute toxicity (LC₅₀, 24 and 48 h) and chronic exposure tests (limited and continuous exposures) were conducted on Daphnia magna. In the chronic limited exposure experiments, Daphnia were exposed to LA-PAM for only 24 h whereas for the chronic continuous exposure the concentrations of 0, 0.5, 1, 5, 10, and 100 mg/L were tested and the endpoints of growth, onset to reproduction, fecundity, and mortality were measured for the duration of 32 days. There was no significant difference among the chronic, limitedly exposed organisms. The acute toxicity for LA-PAM was measured at 100, 150, 200, 250, and 300 mg/L. The acute test showed that the LC₅₀ for LA-PAM was at 152 mg/L. Overall in the chronic, continuous exposure test, D. magna was negatively impacted by LA-PAM at levels as low as 1 mg/L. Growth was reduced by 37% and 89% at 1 and 100 mg/L, respectively. Fecundity and onset to reproduction was impaired at 10 and 100 mg/L. Kinematic viscosity ranged from 0.98 cSt at 1 mg/L to 2.9 at 100 mg/L. At these levels, mechanical and physiological impairments due to the viscous properties of LA-PAM are the proposed mechanisms of reduction in the life history traits of D. magna.
Показать больше [+] Меньше [-]Adsorption Kinetics and Capacity of Fatty Acid-Modified Banana Trunk Fibers for Oil in Water Полный текст
2010
Sathasivam, Kathiresan | Mas Haris, Mas Rosemal Hakim
Oil spill leaves detrimental effects to environment, living organisms, and economy. As such, it is of considerable interest to find an effective, simple, and inexpensive method to treat this calamity. This work reports the use of banana trunk fibers (BTF) modified with oleic acid, stearic acid, castor oil, and palm oil for oil spill recovery. The maximum sorption capacity, effect of oil to water ratio, effect of light oil fractions, and effect of dissolved organic compounds in weathered oil-contaminated seawater were studied. It is found that BTF treated with oleic acid exhibited the best sorption capacity for engine oil, dissolved organic compounds in weathered oil, and light oil fractions. The equilibrium process was described well by the Freundlich isotherm model, and the kinetic studies show good correlation coefficients for a pseudo-second-order kinetic model.
Показать больше [+] Меньше [-]Difference in the Use of a Quartz Filter and a PTFE Filter as First-Stage Filter in the Four-Stage Filter-Pack Method Полный текст
2010
Aikawa, Masahide | Hiraki, Takatoshi
We evaluated the differences in the use of a quartz filter and a polytetrafluoroethylene (PTFE) filter as a first (F0)-stage filter in a four-stage filter-pack method. A four-stage filter-pack method can completely collect sulfur species (SO₂ and SO ₄ ²⁻ ), nitrate species (HNO₃ and NO ₃ ⁻ ), and ammonium species (NH₃ and NH ₄ ⁺ ) with little or no leakage irrespectively of the first-stage filter used. On the other hand, a seasonal variation was observed in the efficiency of collection between the quartz filter and the PTFE filter depending on the material to be collected. There was no seasonal variation in the efficiency of collection in sulfur species; in contrast, a clear seasonal variation was observed for the nitrate and ammonium species. As for NO ₃ ⁻ , the PTFE filter was more vulnerable than the quartz filter at air temperatures below 21°C, while the quartz filter was more vulnerable than the PTFE filter at air temperatures exceeding 21°C. A similar vulnerability for air temperature was observed for NH ₄ ⁺ , although the threshold air temperature was 23°C for NH ₄ ⁺ . Consequently, the evaporation loss of NO ₃ ⁻ would be mainly attributable to the volatilization of NH₄NO₃, although it is also partially due to the volatilization of NH₄Cl.
Показать больше [+] Меньше [-]Cadmium Uptake by Yeast, Candida tropicalis, Isolated from Industrial Effluents and Its Potential Use in Wastewater Clean-Up Operations Полный текст
2010
Rehman, Abdul | Sohail Anjum, Muhammad
This study is aimed at assessing the ability of metal-resistant yeast, Candida tropicalis, to uptake cadmium from the liquid medium. The minimum inhibitory concentration of Cd²⁺ against C. tropicalis was 2,800 mg L⁻¹. The yeast also showed tolerance towards Zn²⁺ (3,100 mg L⁻¹), Ni²⁺ (3,000 mg L⁻¹), Hg²⁺ (2,400 mg L⁻¹), Cu²⁺ (2,300 mg L⁻¹), Cr⁶⁺ (2,000 mg L⁻¹), and Pb²⁺ (1,200 mg L⁻¹). The yeast isolate showed typical growth curves, but low specific rate of growth was observed in the presence of cadmium. The yeast isolate showed optimum growth at 30°C and pH 7. The metal processing ability of the isolate was determined in a medium containing 100 mg L⁻¹ of Cd²⁺. C. tropicalis could decline Cd²⁺ 57%, 69%, and 80% from the medium after 48, 96, and 144 h, respectively. C. tropicalis was also able to remove Cd²⁺ 56% and 73% from the wastewater after 6 and 12 days, respectively. Cd produced an increase in glutathione (GSH) and non-protein thiol levels by 146.15% and 59.67% at 100 mg L⁻¹ concentration, respectively. Metal tolerance and accumulation together with changes in the GSH status and non-protein thiols under Cd exposure were studied in C. tropicalis.
Показать больше [+] Меньше [-]Pollutant Loads Returned to the Lower Murray River from Flood-Irrigated Agriculture Полный текст
2010
Mosley, Luke M. | Fleming, Nigel
Pollutant concentrations and loads returned to the lower Murray River (South Australia) from flood-irrigated agriculture were monitored over a period of 2 years at six locations. This monitoring programme was designed to provide a baseline prior to environmental improvements being undertaken to reduce pollutant loads returned to the river. Pollutant (Escherichia coli, total nitrogen, oxidised nitrogen, total phosphorus, filtered reactive phosphorus and total organic carbon) concentrations were significantly (p < 0.01) higher in the drainage water than the river water and increased during the irrigation season. Salt concentrations were also significantly (p < 0.01) higher in the drainage water than the river inflow water but decreased during the irrigation season because of dilution of the saline groundwater inputs. Pollutant loads exported to the river were significantly higher (p < 0.01-0.05) during the irrigation season for all water quality parameters except oxidised nitrogen. Levels of oxidised nitrogen, filtered reactive phosphorus and E. coli increased in the river downstream of the where the agricultural pollutant inputs begin. Load calculations indicated that this increased water pollution is likely due to the pollutant contributions from the flood-irrigated areas and biogeochemical processing of dissolved nutrients in the river.
Показать больше [+] Меньше [-]Physiological Aspects of Cadmium and Nickel Toxicity in the Lichens Peltigera rufescens and Cladina arbuscula Subsp. mitis Полный текст
2010
Bačkor, Martin | Kováčik, Jozef | Piovár, Juraj | Pisani, Tommaso | Loppi, Stefano
This study was undertaken with the aim of investigating the effect of Cd2+ and Ni2+ containing solutions on selected physiological parameters (metal uptake, chlorophyll a fluorescence, assimilation pigment composition, thiobarbituric acid-reactive substance production, and ergosterol content) in the lichens Peltigera rufescens and Cladina arbuscula subsp. mitis growing on historic copper mine-spoil heaps at Ľubietová-Podlipa, Slovakia. Physiological measurements did not confirm significantly higher sensitivity to Cd and Ni of the cyanolichen P. rurescens compared to the green-algal lichen C. arbuscula subsp. mitis. Under natural conditions, C. arbuscula subsp. mitis is able to grow directly on copper mine heaps of Central Slovakia, while P. rufescens grows only on their margins. A crucial factor for this limited distribution of P. rufescens may be, at least in part, the higher intracellular accumulation of metals. Although lichen photobionts are generally regarded as key elements of lichen sensitivity, further research is necessary to elucidate this point since the higher levels of intracellular Cd and Ni do not allow to regard cyanobacterial photobionts of P. rufescens as more sensitive than the eukaryotic ones of C. arbuscula subsp. mitis.
Показать больше [+] Меньше [-]Multi-criteria Analysis of Air Pollution with SO₂ and PM₁₀ in Urban Area Around the Copper Smelter in Bor, Serbia Полный текст
2010
Nikolić, Djordje | Milošević, Novica | Mihajlović, Ivan | Živković, Živan | Tasić, Viša | Kovačević, Renata | Petrović, Nevenka
This work presents the results of 4 years long monitoring of concentrations of SO₂ gas and PM₁₀ in the urban area around the copper smelter in Bor. The contents of heavy metals Pb, Cd, Cu, Ni, and As in PM₁₀ were determined and obtained values were compared to the limit values provided in EU Directives. Manifold excess concentrations of all the components in the atmosphere of the urban area of the townsite Bor were registered. Through application of a multi-criteria analysis by using PROMETHEE/GAIA method, the zones were ranked according to the level of pollution.
Показать больше [+] Меньше [-]Estimated Quantities and Trends of Cadmium, Lead, and Mercury in US Municipal Solid Waste Based on Analysis of Incinerator Ash Полный текст
2010
Aucott, Michael | Namboodiripad, Ambika | Caldarelli, Adriana | Frank, Kenneth | Gross, Herbert
Heavy metals are present in a variety of products and can be released to the environment during product life cycles. The concentration of metals in municipal solid waste (MSW) reflects the amount of metals in products and is directly related to the amount of metals transferred to disposal sites. Measured monthly mean concentrations of cadmium, lead, and mercury in the ash from May 1995 through October 2007 at the Essex County, NJ incinerator and from May 2004 through November 2007 at the Warren County, NJ incinerator were used, along with air emissions data for mercury, to estimate the content of these metals in MSW. Estimated mean concentration and 95% confidence limits for cadmium in MSW at the Essex and Warren facilities, respectively, were 17.4 ± 0.1 and 10.1 ± 1.2 ppm. For lead, the corresponding values were 408 ± 41 and 239 ± 42 ppm, and for mercury, they were 2.6 ± 0.2 and 0.9 ± 0.2 ppm. A trend of increasing cadmium concentrations was found at both facilities. No change vs. time was observed in lead concentrations. Mercury concentration was found to be decreasing over time at the Essex facility.
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