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Adsorption of Pb, Cd, Cu, Zn, and Ni to titanium dioxide nanoparticles: effect of particle size, solid concentration, and exhaustion Полный текст
2011
Engates, Karen E | Shipley, Heather J
Purpose Adsorption of metals (Pb, Cd, Cu, Ni, Zn) to TiO₂ nanoparticles and bulk particles was examined for use as a contaminant removal substrate as a function of particle size, sorbent concentration, and exhaustion. Methods Adsorption experiments were conducted with 0.01, 0.1, and 0.5 g/L nanoparticles in a pH 8 solution and in spiked San Antonio tap water. Results When results were normalized by mass, nanoparticles adsorbed more than the bulk particles but when results were surface-area normalized, the opposite was observed. The adsorption data shows the ability of the TiO₂ nanoparticles to remove Pb, Cd, and Ni from solution with similar adsorption at 0.1 and 0.5 g/L. Adsorption kinetics for all metals tested was described by a modified first order rate equation with the nanoparticles having a faster rate of adsorption than the bulk particles. The nanoparticles were able to simultaneously removal multiple metals (Zn, Cd, Pb, Ni, Cu) from both pH 8 solution and spiked San Antonio tap water. Exhaustion experiments showed that both the nanoparticles and bulk particles were exhausted at pH 6 but at pH 8, exhaustion did not occur for the nanoparticles. Conclusion Comparison of K d, distribution coefficient, with other literature showed that the nanoparticles were better sorbents than other metal oxide nanoparticles and a commercial activated carbon.
Показать больше [+] Меньше [-]PCDD/F and dioxin-like PCB profiles in soils amended with sewage sludge, compost, farmyard manure, and mineral fertilizer since 1962 Полный текст
2011
Umlauf, Gunther | Christoph, Eugen H | Lanzini, Laura | Savolainen, Risto | Skejo, Helle | Bidoglio, Giovanni | Clemens, Joachim | Goldbach, Heiner | Scherer, Heinrich
Background, aim, and scope Biowaste contains compounds of agricultural value such as organic carbon, nutrients, and trace elements and can partially replace mineral fertilizer (MIN) and improve the physical properties of the soil. However, the obvious benefits of land spreading need to be carefully evaluated against potential adverse effects on the environment and human health. Environmental contamination resulting from biowaste application is one of the key variables when assessing cost/benefits. This study provides data on the resulting concentration of polychlorinated dibenzodioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in the soil column as a result of the different types of fertilizers. Materials and methods In a long-term field experiment established in 1962, we investigated the influence of the application of biowaste-derived fertilizers such as sewage sludge (SSL), compost (COM), and farmyard manure (FYM) to a luvisol derived from loess on the contents of PCDD/Fs and DL-PCBs. Control plots amended only with MIN served as a basis to compare the biowaste-amended soils with soils affected only by atmospheric deposition, thus experimentally separating the two pathways of soil contamination. Samples of the soil column down to a depth of 90 cm were taken in 2001 and analyzed for PCDD/Fs and dioxin-like PCBs according to US-EPA methods 1613 and 1668, respectively. Results Thirty-nine years of experimental SSL and COM applications exceeding four times the maximal amount as laid down in German legislation resulted in a doubling of the international toxicity equivalent (I-TEQ) budget for PCDD/Fs and a threefold increase for DL-PCBs as compared to test plots amended with MIN only. As compared to MIN, the application of FYM had no effect on the PCDD/F and PCB content in soil. The average contribution of the DL-PCBs to the WHO-TEQ was 19% in the MIN and FYM plots and somewhat higher in the COM (23%) and in the SSL (27%) plots. Discussion Although the test plots received four times the maximum application of SSL as laid down in the German SSL ordinance and the investigated region represents the upper end of the topsoil concentrations typically found in Germany, the soils treated with SSL and COM were still a factor of 4 below the German guideline value of PCDD/Fs for arable land. No enhancement of translocation of PCDD/Fs and PCBs into the corresponding subsoils due to the presence of dissolved humic matter or other surfactants potentially present in the biowaste was observed. The similarity of congener patterns in all soils, irrespective of the type of fertilizer applied, points towards atmospheric deposition of PCDD/Fs and DL-PCBs as the main intake route in the soils. The higher levels in the SSL- and COM-amended soils can be explained by the fact that both biowastes are subject to atmospheric deposition occurring at their origin. In the case of COM, it is accumulation in the foliage, while in the case of SSL, atmospheric particulate from wet and dry deposition is collected in the wastewater treatment system via urban runoff. Conclusions It appears that the common practice of SSL applications in Germany does not pose a current threat to the agro-environment with regard to PCDD/Fs and DL-PCBs. However, time trend data on PCDD/Fs in SSL-amended soils will be needed to obtain a prognosis about the long-term effect of biowaste applications on soil quality.
Показать больше [+] Меньше [-]Influence of soluble microbial products (SMP) on wastewater disinfection byproducts: trihalomethanes and haloacetic acid species from the chlorination of SMP Полный текст
2011
Wei, Yuan-yuan | Liu, Yan | Zhang, Yun | Dai, Rui-hua | Liu, Xiang | Wu, Jin-jian | Zhang, Qiang
INTRODUCTION: Effluent organic matter from biological wastewater treatment plants is composed of degradation products and soluble microbial products (SMP). Protein, polysaccharide, humic acid, and DNA were major biomolecules of SMP. Little is known about the effects of SMP as microbially derived precursors on disinfection byproduct formation and speciation in biologically treated wastewater. In addition, there has never been any attempt to directly chlorinate the major biomolecules of SMP. MATERIALS AND METHODS: In this study, model compounds (bovine serum albumin, starch, DNA, and humic acid) and SMP collected from a sequencing batch reactor (SBR) were chlorinated to verify the trihalomethane and haloacetic acid species that were produced from them. RESULTS AND DISCUSSION: The results showed that chloroform, dichlorobromomethane, dichloroacetic acid, and trichloroacetic acid were generated from the chlorination of SMP in the SBR, and there was a close relationship between the species predicted from the model chemical compounds and those obtained from the SMP.
Показать больше [+] Меньше [-]Effects of soil type on leaching and runoff transport of rare earth elements and phosphorous in laboratory experiments Полный текст
2011
Wang, Lingqing | Liang, Tao | Chong, Zhongyi | Zhang, Chaosheng
INTRODUCTION: Through leaching experiments and simulated rainfall experiments, characteristics of vertical leaching of exogenous rare earth elements (REEs) and phosphorus (P) and their losses with surface runoff during simulated rainfall in different types of soils (terra nera soil, cinnamon soil, red soil, loess soil, and purple soil) were investigated. RESULTS AND ANALYSES: Results of the leaching experiments showed that vertical transports of REEs and P were relatively low, with transport depths less than 6 cm. The vertical leaching rates of REEs and P in the different soils followed the order of purple soil > terra nera soil > red soil > cinnamon soil > loess soil. Results of the simulated rainfall experiments (83 mm h⁻¹) revealed that more than 92% of REEs and P transported with soil particles in runoff. CONCLUSION: The loss rates of REEs and P in surface runoff in the different soil types were in the order of loess soil > terra nera soil > cinnamon soil > red soil > purple soil. The total amounts of losses of REEs and P in runoff were significantly correlated.
Показать больше [+] Меньше [-]Concentration-dependent RDX uptake and remediation by crop plants Полный текст
2011
Chen, Diejun | Liu, Z Lewis | Banwart, Wanye
The potential RDX contamination of food chain from polluted soil is a significant concern in regards to both human health and environment. Using a hydroponic system and selected soils spiked with RDX, this study disclosed that four crop plant species maize (Zea mays), sorghum (Sorghum sudanese), wheat (Triticum aestivum), and soybean (Glycine max) were capable of RDX uptake with more in aerial parts than roots. The accumulation of RDX in the plant tissue is concentration-dependent up to 21 mg RDX/L solution or 100 mg RDX/kg soil but not proportionally at higher RDX levels from 220 to 903 mg/kg soil. While wheat plant tissue harbored the highest RDX concentration of 2,800 μg per gram dry biomass, maize was able to remove a maximum of 3,267 μg RDX from soil per pot by five 4-week plants at 100 mg/kg of soil. Although RDX is toxic to plants, maize, sorghum, and wheat showed reasonable growth in the presence of the chemical, whereas soybeans were more sensitive to RDX. Results of this study facilitate assessment of the potential invasion of food chain by RDX-contaminated soils.
Показать больше [+] Меньше [-]An approach to determining potential surrogates for analyzing ecological patterns of planktonic ciliate communities in marine ecosystems Полный текст
2011
Xu, Henglong | Jiang, Yong | Zhang, Wei | Zhu, Mingzhuang | Al-Rasheid, Khaled A. S.
INTRODUCTION: In order to identify a potential surrogate of planktonic ciliate communities for marine bioassessments and evaluating biological conservations, the different taxonomic/numerical resolutions and taxa as surrogates were studied in Jiaozhou Bay, northern China during a 1-year cycle (June 2007–May 2008). MATERIALS AND METHODS: Samples were collected biweekly from a depth of 1 m at each of five sites. A range of physicochemical parameters were also measured in order to determine water quality. RESULTS: The genus- and family-level resolutions maintained sufficient information to evaluate the ecological patterns of the ciliate communities in response to environmental status. The non-loricate oligotrichous ciliate assemblages in both abundance and occurrence may be used as a surrogate of planktonic ciliate communities. Heavy data transformations were an optimal strategy for the species level of planktonic ciliates, while mild data transformations were for the higher. The ordination patterns based on species biomass, occurrence, and biomass/abundance ratio matrices were significantly consistent with that of species abundance data. CONCLUSION: The results suggest that the use of simplifications at both taxonomic and numerical resolutions are time-efficient and would allow improving sampling strategies of large spatial/temporal scale monitoring programs and biological conservation researches in the marine ecosystem with a relative paucity of scientists.
Показать больше [+] Меньше [-]Chlorpyrifos degradation by the cyanobacterium Synechocystis sp. strain PUPCCC 64 Полный текст
2011
Singh, D. P. | Khattar, J. I. S. | Nadda, J. | Singh, Y. | Garg, A. | Kaura, Ainna. | Gulati, A.
BACKGROUND, AIM, AND SCOPE: Indiscriminate use of insecticides leads to environmental problems and poses a great threat to beneficial microorganisms. The aim of the present work was to study chlorpyrifos degradation by a rice field cyanobacterium Synechocystis sp. strain PUPCCC 64 so that the organism is able to reduce insecticide pollution in situ. MATERIAL AND METHODS: The unicellular cyanobacterium isolated and purified from a rice field was identified by partial 16S rRNA gene sequence as Synechocystis sp. strain PUPCCC 64. Tolerance limit of the organism was determined by studying its growth in graded concentrations (2.5–20 mg/L) of chlorpyrifos. Chlorpyrifos removal was studied by its depletion from the insecticide supplemented growth medium, and its biodegradation products were identified in the cell extract, biomass wash, and growth medium. RESULTS AND DISCUSSION: The organism tolerated chlorpyrifos up to 15 mg/L. Major fraction of chlorpyrifos was removed by the organism during the first day followed by slow uptake. Biomass, pH, and temperature influenced the insecticide removal and the organism exhibited maximum chlorpyrifos removal at 100 mg protein/L biomass, pH 7.0, and 30°C. The cyanobacterium metabolized chlorpyrifos producing a number of degradation products as evidenced by GC-MS chromatogram. One of the degradation products was identified as 3,5,6-trichloro-2-pyridinol. CONCLUSION AND RECOMMENDATIONS: Present study reports the biodegradation of chlorpyrifos by Synechocystis sp. Biodegradation of the insecticide by the cyanobacterium is significant as it can be biologically removed from the environment. The cyanobacterium may be used for bioremediation of chlorpyrifos-contaminated soils.
Показать больше [+] Меньше [-]Pesticide removal from waste spray-tank water by organoclay adsorption after field application to vineyards Полный текст
2011
Suciu, Nicoleta A. | Ferrari, Tommaso | Ferrari, Federico | Trevisan, Marco | Capri, Ettore
PURPOSE: The main objective of this work was to develop and test a pilot scheme for decontaminating pesticide-containing water derived from pesticide mixtures used to protect vineyards, in which the scheme comprises adsorption by an organoclay and includes a system where an enhanced or rapid microbial degradation of the adsorbed residues can occur. METHODS: In laboratory experiments, the Freundlich adsorption coefficients of formulations of two fungicides, penconazole and cyazofamid, onto the organoclay Cloisite 20 A were measured in order to predict the efficiency of this organoclay in removing these fungicides from the waste spray-tank water. Subsequently, the adsorption tests were repeated in the pilot system in order to test the practical operation of the depuration scheme. RESULTS: The adsorption tests with the pilot system show 96% removal of both fungicides over a few hours, similar to the efficiency of removal predicted from the laboratory adsorption tests. The formulation type may influence the efficiency of clay recovered after adsorption. Regarding the waste disposal, for instance, the organoclay composted after the treatment, cyazofamid showed significant dissipation after 90 days, whereas the dissipation of penconazole was negligible. CONCLUSION: The depuration scheme developed showed to be efficient for decontaminating pesticide-containing water derived from vineyards, but additional treatments for the adsorbed residues still appear to be necessary for persistent pesticides. However, future decontamination research should be attempted for water contaminated with pesticides containing antifoaming agents in their formulations, in which case the present pilot system could not be applied.
Показать больше [+] Меньше [-]Cultural heritage: a potential pollution source in museum Полный текст
2011
Lee, CheolMin | Kim, YoonShin | Nagajyothi, P. C. | Thammalangsy, Soulighothai | Goung, Sun Ju Nam
Introduction The purposes of this study, as part of research projects for establishing the preservation environment of domestic cultural properties, are to identify the hazardous environmental factors which have a possibility to cause damages on long-term preservation of cultural heritage within the museum exhibition halls and the storages area, and to provide the basic data for the future establishment of preservation environment. Materials and methods The temperature (23.5 and 20.6°C,) relative humidity (52.1% and 55.4%), PM10 (31.5 and 18.9 μg/m3), CO2 (472.7 and 526.8 ppm), HCHO (20.8 and 34.0 μg/m3), CO (0.3 and 0.3 ppm), NO2 (0.012 and 0.004 ppm), TVOCs (493.6 and 788.9 μg/m3), O3 (0.003 and 0.002 ppm), Rn (0.7 and 1.5 pCi/L), and SO2 (0.003 and 0.002 ppm) as chemical factors, and airborne bacteria and fungi as biological factors, were selected for this research subjects of hazardous environmental factors, which were the subjects of the study conducted by the National Research Institute of Cultural Heritage from 2006 to 2008, and the subjects of related domestic researches performed in fragments. Results and discussion The concentration distributions of selected hazardous environmental factors in a museum environment were calculated by using the inverse variance weighted average in meta-analysis, and the concentration distributions possibly emerging in a museum exhibition halls and storages were computed through Monte Carlo simulation in order to minimize the uncertainty that can be caused from meagerness of related domestic researches.
Показать больше [+] Меньше [-]The effect of paraoxon on spermatogenesis in Dugesia gonocephala from the Chilean Altiplano: proliferation and apoptosis Полный текст
2011
Rodríguez, Hector Hernan | Espinoza-Navarro, Omar | Silva, Ivan | Needham, Douglas | Castro, María Eugenia | Sarabia, Luis | Inostroza, Juan | Jimenez, Leonella
Introduction and aims The Chilean Altiplano ecosystem is conserved free from contaminants and pollutants because of the absence of major local human activities such as agriculture or other industries. We studied the effects of paraoxon on proliferation and apoptosis of testicular cells during active spermatogenesis in Dugesia gonocephala collected from a pristine river (Guacollo) in the Altiplano region nearby Visviri town, Chile. Materials and methods Adult planarians were incubated in varying concentrations of paraoxon (0.8, 0.4, 0.04, 0.004, and 0.0004 mM) for 4 h. After 3 h of incubation, bromodeoxyuridine (BrdU) was added. Effects on cell proliferation (BrdU) and apoptosis (Apaf-1) were determined by immunohistochemistry. Results Paraoxon concentrations of 0.4 and 0.8 mM caused 100% mortality in the respective treatment groups. The lowest tested concentration (0.0004 mM) caused a significant increase on cell proliferation in the seminiferous tubules, as well as an increase in the number of apoptotic cells. All other tested concentrations significantly inhibited cell proliferation and induced apoptosis. Conclusions Paraoxon inhibits DNA synthesis and induces apoptosis during spermatogenesis in adult planarians from a high-altitude, pollution-free environment. This could suggest its use as a biosensor or biomarker for contamination with agro pesticides.
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