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Heavy Metals Contamination in Century-Old Manmade Technosols of Hope Bay, Antarctic Peninsula Полный текст
2011
Braga Bueno Guerra, Marcelo | Schaefer, Carlos Ernesto G. R. | de Freitas Rosa, Paula | Simas, Felipe N. B. | Pereira, Thiago T. C. | Rodrigues Pereira-Filho, Edenir
Technosols are anthropogenic soils that may be strongly impacted by heavy metal deposition, which have not yet been described in Antarctica. In this paper, we present a chemical study of what is supposedly the oldest manmade soil from Antarctic Peninsula, developed in the vicinity of Trinity House and Nordenskjold Hut at Hope Bay. Chemical and morphological soil attributes indicate that a former ornithogenic site (penguin rookery) was further subjected to human disturbance, following local exploration since 1903. We detected very high amounts of heavy metals such as Cd, Cu, Pb, and Zn. For the most impacted site, pseudototal concentrations of these elements reach 47, 2,082, 19,381, and 5,225 mg kg−1, respectively. Enrichment factors were calculated using Zr as reference element, and high values were found for these contaminated sites, qualifying some of them as extremely polluted. Also, both the mobilizable and mobile fraction of Cd and Pb indicate the need of intervention in the affected area. These findings are all consistent with the human impacts and strong contamination. Strong positive correlation between the pseudototal concentrations of Cd, Cu, Mn, Ni, Pb, and Zn indicates a similar source of pollution. These soils may represent the oldest Technosols in Antarctic Continent.
Показать больше [+] Меньше [-]Full-Scale Remediation of a Jet Fuel-Contaminated Soil: Assessment of Biodegradation, Volatilization, and Bioavailability Полный текст
2011
Gallego, José Luis R. | Sierra, Carlos | Permanyer, Albert | Peláez, Ana I. | Menéndez-Vega, Demelza | Sánchez, Jesús
Full-Scale Remediation of a Jet Fuel-Contaminated Soil: Assessment of Biodegradation, Volatilization, and Bioavailability Полный текст
2011
Gallego, José Luis R. | Sierra, Carlos | Permanyer, Albert | Peláez, Ana I. | Menéndez-Vega, Demelza | Sánchez, Jesús
Here, we addressed biodegradation vs. volatilization processes, and also bioavailability limitations during biopile remediation of soil initially contaminated by more than 5,000 mg/kg of hydrocarbons. In order to select bioremediation strategies, we first conducted a biotreatability study, which included geochemical, textural, and microbiological characterization of the soil matrix. Next, we implemented five bioremediation approaches onsite in real-scale biopiles. In order to monitor hydrocarbon depletion and to distinguish between biological and non-biological processes, we analyzed chemical biomarkers by means of gas chromatography–mass spectrometry. In addition, a comprehensive study of soil grain size and its implications on bioavailability were studied. Furthermore, the evolution of microbial populations was also examined. Two of the strategies implemented in the biopiles (the combination of a slow-release fertilizer and a surfactant, and the use of an oleophilic fertilizer respectively) reduced the soil hydrocarbon content to under 500 mg/kg in 5 months. Additional results from this study indicate that volatilization was the predominant degradation process for light hydrocarbons (below 12 carbon atoms), whereas heavier compounds were mainly biodegraded. However, even in the most favorable situation, a residual concentration of hydrocarbons linked to the finer fraction of the soil was found.
Показать больше [+] Меньше [-]Full-Scale Remediation of a Jet Fuel-Contaminated Soil: Assessment of Biodegradation, Volatilization, and Bioavailability Полный текст
2011
Rodríguez Gallego, José Luis | Sierra Fernández, Carlos | Permanyer Bastardas, Albert | Peláez Andrés, Ana Isabel | Menéndez Vega, Demelza | Sánchez Martín, Jesús
We thank the company EMGRISA (Spain) for financial and technical support.
Показать больше [+] Меньше [-]Investigating the Real Air Pollution Exchange at Urban Sites Based on Time Variation of Columnar Content of the Components Полный текст
2011
Alföldy, Bálint | Steib, Roland
As a new approach, urban air pollution was characterised by the variation of columnar content of the pollutants. Columnar content (CC) was estimated as the product of the pollutant’s mixing ratio and the mixing height. Mixing ratio data of the Metropolitan Air Quality Monitoring Network of Budapest were used, whilst mixing height was calculated by the meteorological AERMET model code. Time variation of CC refers to the real pollution exchange in the atmosphere that allows direct investigation of the emissions as well as post-emission modifications of the pollutants (such as chemical degradation or production). The diurnal urban CO cycle was found to be determined by two or three main influx peaks according to the traffic pattern of the site. The diurnal variation of NOx level was found to be driven by traffic emission as well. Variant ratios of NOx to CO influxes obtained for the different locations of the city range from 0.12 to 0.23, probably according to the vehicle composition of the traffic. The daily balance of photochemical production, chemical degradation and deposition of ozone yielded negative or positive depending on the location. Negative balances imply that the polluted urban atmosphere is a net ozone neutraliser source. Entrainment from the free troposphere yielded the major contributor to the diurnal ozone level at each site. The diurnal urban PM10 cycle was found to be determined by traffic emission during the morning and evening rush hours whilst secondary aerosol formation around noon. In the evening, high PM10 level rise was observed due to direct traffic emission as well as rapid conversion of the fine aerosol fraction to the coarse fraction.
Показать больше [+] Меньше [-]Equilibrium Modeling for Biosorption of Safranin onto Chemically Modified Biomass of Marine Aspergillus wentii Полный текст
2011
Safranin was used as a model reactive dye for biosorption studies onto various forms of chemically modified biomass of Aspergillus wentii. The experimental equilibrium data was analyzed by various single-, two-, three-, four-, and five-parameter isotherms to understand the biosorption process. Biosorption isotherms modeling shows that the interaction of safranin with A. wentii surface is localized monolayer sorption. Results show that in general the accuracy of models to fit experimental data improves with the degree of freedom. The interaction among adsorbed molecules is repulsive having no association between them and sorption is carried out on energetically different sites and is an endothermic process. The five-parameter Fritz–Schluender model gives the most accurate fit with high regression coefficients (0.9902–0.9941), low standard errors (0.0389–0.0758), and sum of squares error (0.0075–0.0230) values to all experimental data in comparison to other models. The results disclose that the sorption isotherm models fitted the experimental data in the order: Fritz–Schluender (five-parameter) > Langmuir > Khan > Fritz–Schluender (four-parameter) > Temkin. This systematic evaluation of the more important equilibrium isotherm models provided the general basis for making a preliminary selection of an effective model for a given application.
Показать больше [+] Меньше [-]Repeatability Evaluation of Instrumented Column Tests in Cover Efficiency Evaluation for the Prevention of Acid Mine Drainage Полный текст
2011
Demers, Isabelle | Bussière, Bruno | Aachib, Mostafa | Aubertin, Michel
Instrumented column tests are often used to assess the effectiveness of methods to prevent acid mine drainage (AMD). These tests are seldom duplicated, and this lack of duplicate can cast some doubt about their repeatability and reliability. This paper provides an analysis of column test studies (with duplicates) performed with a commonly used methodology. The paper presents the analysis of two multi-layer covers with capillary barrier effects in which the water retention layer was made of a non-plastic silt and of two cover scenarios involving a single-layer low sulphide cover. The first study compared the cover performance to limit AMD when different cover materials are used, while the second study compared the thickness of covers on cover performance. Statistical comparison between duplicates was made using available geochemical data, hydro-geotechnical data, and gas concentrations. Student’s t-test statistical tools and analysis of variances were used to determine the repeatability of the data. The results indicate that a good reproducibility of the column tests can be achieved with a good set-up methodology and rigorous control of the boundary conditions.
Показать больше [+] Меньше [-]Ultrastructural Alterations in the Midgut of Diplopods after Subchronic Exposure to Substrate Containing Sewage Mud Полный текст
2011
Nogarol, Larissa Rosa | Fontanetti, Carmem Silvia
The use of sewage mud in agriculture has generated several discussions due to the risks of soil contamination mainly by metals. Due to the intimate contact of the diplopods with soil, they have been successfully used in ecotoxicological analyses. The impact of the external environment in the physiological changes in organs and tissues of different organisms can be reflected by the ultrastructural changes of their cells. Using the transmission electron microscopy, this study aimed to analyze the ultrastructural alterations in the midgut of the diplopod Rhinocricus padbergi exposed to substrate containing sewage mud from a Sewage Treatment Station of São Paulo State, Brazil. Therefore, it was sought to identify cellular alterations resulting from the subchronic exposure (90 days of exposure) of the animals to complex and potentially toxic mixtures such as sewage mud at different concentrations (1%, 10%, and 50%). The control group presented integrity in the cells and tissues that constitute the midgut. The animals exposed to sewage mud at 10% and 50% died before the 90 days of exposure. The analysis of the midgut of the animals exposed to 1% of sewage mud showed alterations in the epithelial cells, cells of the fat body layer, and hepatic cells. The main alterations observed were cytoplasmatic vacuolization, loss of the plasmatic membrane, and nuclear envelope integrity. We conclude that the mud sample presents a mixture of complex substances of cytotoxic and genotoxic action to the diplopod, causing cell death, since both the nucleus and other cellular compartments were damaged.
Показать больше [+] Меньше [-]Fluctuating Asymmetry of Chironomus spp. (Diptera: Chironomidae) Larvae in Association with Water Quality and Metal Pollution in Permatang Rawa River in the Juru River Basin, Penang, Malaysia Полный текст
2011
Al-Shami, Salman Abdo | Che Salmah, Mad Rawi | Abu Hassan Ahmad, | Siti Azizah Mohd Nor,
The levels of fluctuating asymmetry [random differences between symmetric organismal traits, fluctuating asymmetry (FA)] in the fourth instar of Chironomus spp. larvae inhabiting an agrochemical polluted river [Permatang Rawa River (PRR)] in the Juru River Basin, northeastern peninsular Malaysia, were measured. The PRR receives waters primarily from adjacent rice fields which are exposed to fertilizer and pesticide residues. Samples of larvae, water, and sediments were collected monthly from November 2007 to June 2008. In situ measurements of water pH and dissolved oxygen were made at three sampling locations along the river. Monthly water and benthic sediment collections were also conducted for the following laboratory water analyses: biological oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), and ammonium-N content. Non-residual metals in the sediment samples were also analyzed. The water quality index (WQI) of the PRR was also calculated. This study attempted to relate FA levels based on selected traits of Chironomus spp. larval head capsule (mentum width and first and second antennal segment length) to water quality and sediment heavy metal contamination in the PRR. All monthly measurements of FA levels including transcriptors (FA10a, FA4a, ME3, and ME1) and indices [FA, absolute asymmetry (AbsFA), and composite fluctuating asymmetry (CFA)] were calculated. The ordination model of redundancy analysis showed that the dissolved oxygen and water quality in the river expressed as WQI were negatively correlated with all FA indices (FA, AbsFA, and CFA) of the larval mentum width and length of antennal segments I and II. The water pH, BOD, and COD and sediment Cu positively influenced the FA incidence in the larval mentum. The FA indices of the antennal segment I were positively correlated with the increase in the levels of water pH, ammonium-N, BOD, and COD. The FA indices, especially CFA, were sensitive to the water pH and ammonium-N and sediment contaminated by Mn, Cu, and Zn. The FA levels calculated as FA indices of the larval antennal segment II length were positively correlated with water TSS and sediment Mn, Cu, Zn, and Ni. This study revealed that the river water quality and heavy metal contamination affect developmental stability in Chironomus spp. larvae. The FA indices of different structures in the Chironomus spp. larval head capsule could be used as bioindicators for water and sediment pollution.
Показать больше [+] Меньше [-]Treatment of Acid Mine Drainage Using Fly Ash Zeolite Полный текст
2011
Prasad, Bably | Mortimer, Robert J. G.
In this paper, two Indian fly ashes (from Talcher and Ramagundam) were converted into zeolites and both the raw fly ash and zeolite were used to treat two British acidic mine waters. The results demonstrate that fly ash zeolites are more effective than raw fly ash for treatment of acid mine drainage. Fly ash has been found effective for removal of Pb, but with increased dosing, caused release of Ba, Cr, Sr (both fly ashes) plus Zn, Ni (Talcher), or Fe (Ramagundam) into mine water. In contrast, increased dosing with fly ash zeolite removed 100% Pb, 98.9% Cd, 98.8% Zn, 85.6% Cu, 82.8% Fe, 48.3% Ni, and 44.8% Ba from mine water. Fly ash is amorphous in nature and many metals attached on the surface of the ash particles are easily leached off when ash comes in contact with acidic mine water. However, fly ash zeolite is crystalline in nature and due to its high cation exchange properties, most of the metals present in acid mine water are retained in surface sites.
Показать больше [+] Меньше [-]Identification, Apportionment, and Photochemical Reactivity of Non-methane Hydrocarbon Sources in Busan, Korea Полный текст
2011
Choi, Eunhwa | Heo, Jong-Bae | Hopke, Philip K. | Jin, Byong-Bok | Yi, Seung-Muk
Hourly concentrations of non-methane hydrocarbons (NMHCs) recorded between June and August 2006, at two monitoring sites (Gijang and Jin) in Busan were analyzed to examine the characteristics and photochemical reactivity of NMHC sources. The two sites represent urban (Jin) and suburban (Gijang) Busan, which is a typical Korean city. Positive matrix factorization (PMF), applied to identify and apportion the sources of NMHCs, revealed nine sources for Gijang and ten sources for Jin. To explore the contribution of each NMHC source to ozone formation at the two sampling sites, the ozone formation potential was estimated for each source. The largest contributors to ozone formation were sources characterized by 1,2,3-trimethylbenzene (26.4%) at Gijang and by toluene, ethylbenzene, and xylenes (22.5%) at Jin, which were composed mostly of heavy hydrocarbons and aromatics. Secondary sources included two coating sources (20.9%, 12.2%) and vehicle exhaust (10.3%) at Gijang and a source represented by toluene (17.4%), vehicle exhaust (15.9%), and a coating-2 source (9.6%) at Jin. Conditional probability function (CPF) and potential source contribution function (PSCF) analysis methods were used to identify the directions of local sources and to locate potential source regions, respectively. The CPF and PSCF results agreed well for the majority of sources resolved by PMF and thus were very useful in identifying the major sources contributing to ozone formation at the two study sites.
Показать больше [+] Меньше [-]Short-Term Effects of Arsenate-Induced Toxicity on Growth, Chlorophyll and Carotenoid Contents, and Total Content of Phenolic Compounds of Azolla filiculoides Полный текст
2011
Sánchez-Viveros, Gabriela | Ferrera-Cerrato, Ronald | Alarcón, Alejandro
This study evaluated the toxic effects of arsenic (As) on the growth, total antioxidant activity, total content of phenolic compounds, and content of photosynthetic pigments of Azolla filiculoides. The aquatic fern was propagated and exposed to Yoshida nutrient solution contaminated with sodium arsenate (Na2HAsO4·7H2O) at six concentrations (5, 10, 20, 30, 60, and 120 μgâAsâmL−1), including the control without As contamination. Azolla cultures were kept under environmental chamber conditions 26°C, 12 h photoperiod and 80% HR for 96 h. Increased As concentrations (>30 μgâmL−1) significantly diminished growth of A. filiculoides and the total content of chlorophyll and total phenolic compounds, but significantly enhanced of total carotenoidâ+âxanthophylls content. The concentrations of 5 and 10 μgâAsâmL−1 significantly stimulated the growth of A. filiculoides. This aquatic fern tolerates As concentrations lower than 30 μgâmL−1, and its maximum As accumulation (28 μgâg−1 dry weight) was achieved when exposed to 60 μg As mL−1, but showing clear symptoms of As toxicity.
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