Уточнить поиск
Результаты 1891-1900 из 4,044
Effect of Weathered Coal on the Leaching Behavior of Lead-Contaminated Soil with Simulated Acid Rain Полный текст
2016
Liu, Jiahao | Li, Hua | Wu, Ruiping | Zhu, Yuen | Shi, Weiyu
Lead (Pb) has progressively become a widespread contaminant in the environment because of its intensive use and inherent stability. The contamination of Pb in agricultural soils is a major environmental problem. This paper considers the use of weathered coal humic acids for in situ remediation of Pb-contaminated soils. The effectiveness of acid rain on leaching in soil column was investigated. To determine the mobility and availability of Pb, we also investigated the soil pH and available soil Pb content from different depths in addition to the leachate pH and Pb concentrations at different times. Weathered coal has the potential to adjust the soil pH and leachate pH through metal-bridging mechanisms and deprotonation processes. We found that weathered coal humic acid and simulated acid rain significantly decreased the available surface soil Pb concentrations. The decrease in the available Pb concentrations in the surface layers of the soil was related to a significant increase in the available Pb concentrations in the middle layers of the soil. The application of weathered coal humic acid could reduce the Pb concentration of soil leachates. The removal of Pb was efficient, particularly at the 1000-mg-kg⁻¹ Pb pollution level, with a maximum decrease of 85.8 %.
Показать больше [+] Меньше [-]Detecting the exposure to Cd and PCBs by means of a non-invasive transcriptomic approach in laboratory and wild contaminated European eels (Anguilla anguilla) Полный текст
2016
Baillon, Lucie | Pierron, Fabien | Oses, Jennifer | Pannetier, Pauline | Normandeau, Eric | Couture, Patrice | Labadie, Pierre | Budzinski, Hélène | Lambert, Patrick | Bernatchez, Louis | Baudrimont, Magalie
Detecting and separating specific effects of contaminants in a multi-stress field context remain a major challenge in ecotoxicology. In this context, the aim of this study was to assess the usefulness of a non-invasive transcriptomic method, by means of a complementary DNA (cDNA) microarray comprising 1000 candidate genes, on caudal fin clips. Fin gene transcription patterns of European eels (Anguilla anguilla) exposed in the laboratory to cadmium (Cd) or a polychloro-biphenyl (PCBs) mixture but also of wild eels from three sampling sites with differing contamination levels were compared to test whether fin clips may be used to detect and discriminate the exposure to these contaminants. Also, transcriptomic profiles from the liver and caudal fin of eels experimentally exposed to Cd were compared to assess the detection sensitivity of the fin transcriptomic response. A similar number of genes were differentially transcribed in the fin and liver in response to Cd exposure, highlighting the detection sensitivity of fin clips. Moreover, distinct fin transcription profiles were observed in response to Cd or PCB exposure. Finally, the transcription profiles of eels from the most contaminated site clustered with those from laboratory-exposed fish. This study thus highlights the applicability and usefulness of performing gene transcription assays on non-invasive tissue sampling in order to detect the in situ exposure to Cd and PCBs in fish.
Показать больше [+] Меньше [-]Functional Diversity and Microbial Activity of Forest Soils that Are Heavily Contaminated by Lead and Zinc Полный текст
2016
The objective of this study was to assess the impact of metal contamination on microbial functional diversity and enzyme activity in forest soils. This study involved the evaluation of the influence of the texture, carbon content and distance to the source of contamination on the change in soil microbial activity, which did not investigate in previous studies. The study area is located in southern Poland near the city of Olkusz around the flotation sedimentation pond of lead and zinc at the Mining and Metallurgical Company “ZGH Bolesław, Inc.”. The central point of the study area was selected as the middle part of the sedimentation pond. The experiment was conducted over a regular 500 × 500-m grid, where 33 sampling points were established. Contents of organic carbon and trace elements (Zn, Pb and Cd), pH and soil texture were investigated. The study included the determination of dehydrogenase and urease activities and microbial functional diversity evaluation based on the community-level physiological profiling approach by Biolog EcoPlate. The greatest reduction in the dehydrogenase and urease activities was observed in light sandy soils with Zn content >220 mg · kg⁻¹ and a Pb content > 100 mg · kg⁻¹. Soils with a higher concentration of fine fraction, despite having the greatest concentrations of metals, were characterized by high rates of Biolog®-derived parameters and a lower reduction of enzyme activity.
Показать больше [+] Меньше [-]Two Novel Biofilters to Remove Volatile Organic Compounds Emitted by Landfill Sites Полный текст
2016
Lakhouit, Abderrahim | Cabral, Alexandre R. | Cabana, Hubert
The present work investigates the potential of two experimental field columns (FC-2 and FC-4) to reduce volatile organic compound (VOC) emissions from a municipal solid waste (MSW) landfill located in Quebec, Canada. The FC-2 and FC-4 were fed by raw biogas coming from the landfill site. The VOC were identified and quantified in emitted biogas and raw biogas. The emitted biogas was collected at the surface of FC-2 and FC-4, and the raw biogas was obtained directly from the well. The main groups of the VOC in the landfill biogas are BTEX (66 %), alkanes (19 %), cyclic compounds (10 %), and halogenated compounds (5 %). The concentration of VOC in the landfill raw biogas varies from below the limit of detection (BLD) to 22 ppmv, and that of the emitted biogas varies from BLD to 3.1 ppmv. The result of this study showed that the experimental field columns had a very high potential to reduce the VOC emissions from the investigated landfill. The effectiveness of the VOC emission removal for the FC-2 and FC-4 was shown to be practically 100 % for many compounds. The experimental field column elimination capacity of VOC emissions is in the range of 0.1 to 4.6 mg m⁻³ h⁻¹.
Показать больше [+] Меньше [-]How Selenium Affects Berula erecta Полный текст
2016
Mechora, Špela | Sotler, Metka | Krajnc, AndrejaUrbanek | Ambrožič-Dolinšek, Jana
In the presented in vitro experiment, the effect of selenite treatment (0.01, 0.1, 1, 10 and 50 mg L⁻¹ Se(IV)) on Berula erecta was investigated with respect to growth, photochemical efficiency, photosynthetic pigments, anthocyanins and low molecular weight thiols. Lower Se(IV) concentrations (0.01, 0.1 and 1 mg L⁻¹) promoted growth, while higher Se(IV) concentrations (10 and 50 mg L⁻¹) negatively affected it. The photochemical efficiency of photosystem II decreased significantly in plants treated with higher Se(IV) concentrations, compared to that in the control plants. The content of pigments decreased in all the Se(IV) treatments. Both cysteine and glutathione showed alterations in their content and redox state depending on the Se concentration. By evaluating the glutathione/cysteine system and their redox, it was possible to identify a threshold Se content (1-mg Se(IV) L⁻¹ treatment), above which the nature of the effects induced changes from antioxidant to pro-oxidant.
Показать больше [+] Меньше [-]Three Functional Biomarkers for Monitoring the Nanoscale Zero-Valent Iron (nZVI)-Induced Molecular Signature on Soil Organisms Полный текст
2016
Fajardo, Carmen | Costa, Gonzalo | Nande, Mar | Martín Velasco, Margarita
Currently, there are increasing efforts to utilize nanoremediation as an environmental technology for cleaning up polluted environments using nanoscale zero-valent iron (nZVI); however, concerns exist regarding the long-term environmental impact of this strategy. In this study, an innovative methodology for evaluating nZVI impact on soil bacteria is utilized, based on transcriptional analysis of three novel biomakers: tnaA, sodB and trx genes. At the same time, classical toxicological bioassays with the nematode Caenorhabditis elegans were performed. Microcosms treated with 1, 5 and 10 % w/w of nZVI were set up using a commercial standard soil and incubated for 21 days. The tnaA gene, involved in indole production, was significantly upregulated at all assessed nZVI concentrations, suggesting that bacterial cells used this molecule to inform the rest of the community about the changes produced upon nZVI soil treatment. The higher the exposure time, the lower nZVI concentration needed to detect these changes. Consequently, soil bacteria activate a cellular adaptive response to cope with the nZVI-induced oxidative stress, increasing the expression of genes encoding key reactive oxygen species (ROS)-scavenging enzymes; in fact, an upregulation of the sodB and katB genes was recorded upon nZVI exposure. On the contrary, C. elegans survival and growth endpoints were not affected at any nZVI concentration whereas the exposure time significantly increased nematode growth in the soil. Therefore, despite the lack of toxicity revealed by the classical conducted tests, the transcriptional analyses demonstrated the usefulness of combining the set of proposed biomarkers for early detection and monitoring the impact of nZVI on soil bacteria after environmentally important periods of exposure.
Показать больше [+] Меньше [-]Application of Wastewater and Biosolids in Soil: Occurrence and Fate of Emerging Contaminants Полный текст
2016
Mohapatra, D. P. | Cledón, M. | Brar, S. K. | Surampalli, R. Y.
Wastewater (WW) for irrigation and application of biosolids in soil is becoming important as it is going to become very common in the near future. By 2050, the world is going to have four billion people living in water-scarce countries, making it a norm of freshwater for the cities and WW for agriculture. Further, biosolids might still be used as green biofertilizers for soils, if they are improved from an ecological point of view. However, application of biosolids in soil is argued because of the amount of organic pollutants that compromise the dynamic equilibrium of the biological systems. Therefore, information on the concentration, behavior, and cycling of organic pollutants as well as their possible degradation pathways is needed to predict, prevent, and remediate these pollutants from different sources including WW and biosolids. Among the group of organic pollutants, emerging contaminants (ECs) enter into the soil with the irrigation water from treated effluents and fertilization by biosolids. Quantification of ECs from WW and biosolids is of main importance to predict the toxic effects of WW effluents and sludge. Moreover, their incorporation into vegetables through irrigation and their magnification through natural food webs have been proved and must be monitored. This review presents information on the different sources of emerging contaminants and linking with the ecological effects they produced by reacting in the environment during various applications of WW and biosolids in soil. The available methods for analysis and quantification of ECs in different matrices, such as WW and biosolids, are also presented.
Показать больше [+] Меньше [-]Removal of Cu(II) from Water Samples Using Glycidyl Methacrylate-Based Polymer Functionalized with Diethylenetriamine Tetraacetic Acid: Investigation of Adsorption Characteristics Полный текст
2016
Yayayürük, Onur | Erdem Yayayürük, Aslı
A macroporous glycidyl methacrylate (GMA)–methylmethacrylate (MMA)–divinyl benzene (DVB) terpolymer functionalized with diethylenetriamine tetraacetic acid (DTTA) (GMA-MMA-DVB-DTTA) sorbent was successfully applied for the uptake of Cu(II) from the aqueous solutions. Adsorption characteristics for copper ion were investigated by a batch sorption in under different experimental conditions, and the optimum parameters for the quantitative sorption of Cu(II) ion were found to be as follows: pH of 7.0, a contact time of 30.0 min, and a sorbent amount/solution volume ratio of 1.5 mg/mL. The quantitative elution from the sorbent was performed with 1.0 M HCl (>95 %). Among three kinetic models, the pseudo-second-order kinetic model provides the best correlation for the process. The nonlinear resolution of the Langmuir isotherm equation has been found to show the closest fit to the equilibrium data. The results indicates that the presence of the competitor ions (Al, Ba, Co, Mn, Mg, and Ni) has no obvious influence on the sorption of Cu(II) ion under the optimum conditions and the polymeric sorbent has a good selectivity for the sorption of Cu(II) ions with a sorption percent of ≥99 %. Sorption/desorption studies were performed for ultrapure, tap, bottled drinking and industrial wastewater samples, and it is examined that the proposed method has been successfully applied to the real samples for the removal of Cu(II) acceptable accuracy and precision. The results of this work indicated that the polymeric sorbent could be a simple and suitable method for the effective removal of Cu(II) ions from waters.
Показать больше [+] Меньше [-]Copper(II) and Phenol Adsorption by Cell Surface Treated Candida tropicalis Cells in Aqueous Suspension Полный текст
2016
Honfi, Krisztina | Tálos, Katalin | Kőnig-Péter, Anikó | Kilár, Ferenc | Pernyeszi, Tímea
An experimental study was performed to determine the feasibility of using physically treated Candida tropicalis cells for sorption of Cu(II) and phenol, the role of competition between phenol molecules and Cu(II). The yeast cells were lyophilized (LC), heat-treated at 65 °C for 24 h (HT1), at 90 °C for 24 h (HT2), and 72 h (HT3), inactivated at 120 °C and 104 kPa for 20 min (PC). The adsorption isotherms were determined in batch system. Experimental equilibrium data were evaluated using Langmuir, Freundlich, and Dubinin–Radushkevich isotherm models by linear and non-linear regression. The adsorbed Cu(II) and phenol amounts by yeast cells were decreased due to the physical treatments of cells. With the increase of biomass dosage from 1 to 10 g L⁻¹, the adsorption efficiency was increased. The Cu(II) adsorption capacity was also determined in the presence of phenol at various initial concentrations, and in these systems, phenol adsorption isotherms were determined. In the presence of phenol, the Cu(II) sorption capacity by lyophilized cells and carbon particles was decreased. The most commonly used sorbent in water treatment is activated carbon with large specific surface; therefore, the results were compared with the experimental data obtained by using activated carbon (AC).
Показать больше [+] Меньше [-]Arsenic and chromium topsoil levels and cancer mortality in Spain Полный текст
2016
Núñez, Olivier | Fernández-Navarro, Pablo | Martín-Méndez, Iván | Bel-Lan, Alejandro | Locutura, Juan F. | López-Abente, Gonzalo
Spatio-temporal cancer mortality studies in Spain have revealed patterns for some tumours which display a distribution that is similar across the sexes and persists over time. Such characteristics would be common to tumours that shared risk factors, including the chemical soil composition. The objective of the present study is to assess the association between levels of chromium and arsenic in soil and the cancer mortality. This is an ecological cancer mortality study at municipal level, covering 861,440 cancer deaths in 7917 Spanish mainland towns from 1999 to 2008. Chromium and arsenic topsoil levels (partial extraction) were determined by ICP-MS at 13,317 sampling points. To estimate the effect of these concentrations on mortality, we fitted Besag, York and Mollié models, which included, as explanatory variables, each town’s chromium and arsenic soil levels, estimated by kriging. In addition, we also fitted geostatistical-spatial models including sample locations and town centroids (non-aligned data), using the integrated nested Laplace approximation (INLA) and stochastic partial differential equations (SPDE). All results were adjusted for socio-demographic variables and proximity to industrial emissions. The results showed a statistical association in men and women alike, between arsenic soil levels and mortality due to cancers of the stomach, pancreas, lung and brain and non-Hodgkin’s lymphomas (NHL). Among men, an association was observed with cancers of the prostate, buccal cavity and pharynx, oesophagus, colorectal and kidney. Chromium topsoil levels were associated with mortality among women alone, in cancers of the upper gastrointestinal tract, breast and NHL. Our results suggest that chronic exposure arising from low levels of arsenic and chromium in topsoil could be a potential risk factor for developing cancer.
Показать больше [+] Меньше [-]