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Occurrence and Concentration Levels of Nitro-PAH in the Air of Three Brazilian Cities Experiencing Different Emission Impacts Full text
2008
de Castro Vasconcellos, Pérola | Sanchez-Ccoyllo, Odon | Balducci, Catia | Mabilia, Rosanna | Cecinato, Angelo
Nitrated Polycyclic Aromatic Hydrocarbons (NPAH) were determined in the suspended particulates collected in São Paulo (Brazil) and three other cities lying in the São Paulo State, (namely, Araraquara, Piracicaba and Paulínia), during August 2002 and July 2003. São Paulo samples represented a big difference between two groups of days, one of which characterized by heavy injection of pollutants released by industrial and agricultural activities. Most NPAH congeners identified in the atmosphere were among those usually associated to diesel exhaust, with the three important exceptions of 2-nitrofluoranthene, 2- and 4-nitropyrene. Daytime reactions seemed to promote decomposition of primary fluoranthene and pyrene. Trends of NPAH at all sites seemed to be associated to regional transport of polluted air through air masses passing over sugar cane plantations of São Paulo State.
Show more [+] Less [-]Analysis and Sorption Behavior of Fluoroquinolones in Solid Matrices Full text
2008
Uslu, M Ötker | Yediler, A. | Balcıoğlu, I Akmehmet | Schulte-Hostede, S.
A simple analytical method for the quantitative analysis of fluoroquinolone group antibiotics, enrofloxacin (ENR) and ciprofloxacin (CIP) in soil was developed based on the mechanical extraction with vortex and ultrasonication and solid phase extraction followed by high pressure liquid chromatography-fluorescence detection (HPLC-FLD). Type of extraction solvents and number of extraction cycles were optimized during the method development. The most efficient extraction solvent was found as phosphate buffer at pH 3 in combination with 50% of organic modifier acetonitrile with the extraction cycle of four. Overall method was applied on three different types of soils, namely, sandy, loamy sand and sandy loam and recovery rates ranged between 71-100% for ENR and 61-89% for CIP depending on the portion of organic and clay content in soils. The analytical method was also used for the estimation of fluoroquinolone concentrations in manure amended agricultural soils sampled from the different parts of Turkey and enrofloxacin was detected in the concentration range of 0.013-0.204 mg/kg. In addition, sorption of fluoroquinolone antibiotics on all types of soils was investigated and the highest distribution coefficients (Kd and Kf) of fluoroquinolone compounds were obtained for loamy sand (Kd = 1.29 l/g and Kf = 0.66 for CIP; Kd = 0.97 l/g and Kf = 0.56 for ENR) with the highest organic carbon.
Show more [+] Less [-]A Comparison of Gravity Distribution Devices Used in On-Site Domestic Wastewater Treatment Systems Full text
2008
Patel, T. | O’Luanaigh, N. | Gill, L. W.
A detailed analysis of different types of gravity distribution devices, designed to split on-site wastewater effluent equally between percolation trenches, has been carried out both in the laboratory and also in the field under realistic loading conditions. Four different types of distribution device have been compared: a V-notch distribution box, stilling chamber box and tee-splitters with and without baffles. The trials carried out in the laboratory with clean water showed that flow distribution for all devices was sensitive to both the off-level installation angles and variable flow rates, with the most stable performance achieved using the flow splitter with upstream baffle plates. In parallel to this, the on-site flow regime experienced at two sites was continuously monitored using a tipping bucket and data-logger over twelve month periods, finding that the most common flow rates at the distribution unit were in the range of 0.1–2.5 l min⁻¹. The on-site performance of these devices receiving both septic tank and secondary treated effluent showed that significant solid deposition and biofilm development had severely affected the equal distribution between the trenches, hence highlighting the need for regular maintenance to ensure efficient performance over time after installation.
Show more [+] Less [-]Odor Control for Land Application of Lime Stabilized Biosolids Full text
2008
Krach, Kenneth R | Burns, Benjamin R | Li, Baikun | Shuler, Alison | Cole, Charles | Xie, Yuefeng
Over three million dry metric tons of biosolids produced in the United States are land applied as Class B. Lime stabilization is employed for biosolids treatment at approximately 20% of the wastewater treatment plants because it is a simple and inexpensive process. During lime stabilization, the pH of sewage sludge is raised above 12 for pathogen inactivation and odor reduction. Lime dose and mixing have been found to greatly reduce odor generation from lime stabilized biosolids. A better quality biosolids product is less likely to create public opposition to land application programs. In this study, land application tests using Class B biosolids were conducted in order to determine whether better mixing can reduce odor generation during the land application of lime stabilized biosolids. The mixing quality of a treatment plant's lime stabilized biosolids was improved by relocating the lime addition point, which prolonged the mixing time and produced a better mixed biosolids product. Based on field observations of land application, the poorly mixed biosolids were more odorous and offensive prior to incorporation. However, once incorporated into the soil, there was no appreciable odor difference between the biosolids. Another land application study was conducted to assess the odor of unincorporated Class A biosolids and compare it with incorporated Class A biosolids with the soil.
Show more [+] Less [-]Determination of Environmental Quality of a Drinking Water Reservoir by Remote Sensing, GIS and Regression Analysis Full text
2008
Coskun, H Gonca | Tanik, Aysegul | Alganci, Ugur | Cigizoglu, H Kerem
Istanbul, housing a population over ten million and with population increase rate of approximately twice that of Turkey, is one of the greatest metropolitan cities of the world. As a consequence of rapid population growth and industrial development, Omerli watershed is highly affected by wastewater discharges from the residential areas and industrial plants. The main objective of this study is to investigate the temporal assessment of the land-use/cover of the Omerli Watershed and the water quality changes in the Reservoir. The study is mainly focused on the acquisition and analysis of the Satellite Probatoire de l'Observation de la Terre (SPOT) (1993), Indian Remote Sensing satellite (IRS) (1996 and 2000) and Landsat Thematic Mapper (TM) (2004, 2005, and 2006) satellite images that reflect the drastic land-use/cover changes utilizing the ground truth measurements. The rapid, uncontrolled, and illegal urbanization coupled with insufficient infrastructure has caused the deterioration of the water quality within the past two decades in the Omerli watershed. The water quality analysis of the drinking water Reservoir within the watershed is investigated using 2006 dated Landsat TM satellite digital data. The results are compiled and compared with the water quality measurements of parameters like total nitrogen (TN), the total phosphorus (TP), chlorophyll a (CL) and total dissolved solids (TDS). The observed reflectance shows a strong relationship with the water quality parameters and thus, the satellite data proved to provide a useful index of TN, TP, CL and TDS. Moreover, the linkage between the water quality parameters and the individual band reflectance values are supported by multiple regression analysis.
Show more [+] Less [-]Novel Mercury Oxidant and Sorbent for Mercury Emissions Control from Coal-fired Power Plants Full text
2008
Lee, Joo-Youp | Ju, Yuhong | Lee, Sang-Sup | Keener, Tim C | Varma, Rajender S
The authors have successfully developed novel efficient and cost-effective sorbent and oxidant for removing mercury from power plant flue gases. These sorbent and oxidant offer great promise for controlling mercury emissions from coal-fired power plants burning a wide range of coals including bituminous, sub-bituminous, and lignite coals. A preliminary analysis from the bench-scale test results shows that this new sorbent will be thermally more stable and cost-effective in comparison with any promoted mercury sorbents currently available in the marketplace. In addition to the sorbent, an excellent elemental mercury (Hg(0)) oxidant has also been developed, and will enable coal-fired power plants equipped with wet scrubbers to simultaneously control their mercury emissions as well as their sulfur oxides emissions. This will work by converting all elemental mercury to an oxidized form which will be removed by the wet scrubber. This will result in significant cost savings for mercury emissions control to the atmosphere, and will help in keeping electric costs low. The sorbent and oxidant will benefit from the utilization of a waste stream from the printed circuit board (PCB) industry, and would thus be environmentally beneficial to both of the utility and electronics industries. The sorbent also demonstrated thermal stability up to 350°C, suggesting a possibility of an application in pulverized coal-fired power plants equipped with hot-side electrostatic precipitators and coal gasification plants.
Show more [+] Less [-]Species Diversity and Community Structure of Ground-Dwelling Spiders in Unpolluted and Moderately Heavy Metal-Polluted Habitats Full text
2008
Jung, Myung-Pyo | Kim, Sŭng-tʻae | Kim, Hunsung | Yi, Chun-ho
This study was conducted to investigate the relationship between ground-dwelling spider communities and the degree of soil contamination of heavy metals, Cd and Pb. Six sites were selected according to expected differences in Cd and Pb contamination levels in soil and similarity in vegetation composition. Ground-dwelling spiders were collected monthly in 2003 and 2004 by pitfall trapping. Species diversity of ground-dwelling spiders between unpolluted and moderately polluted sites was not significantly different although the value was higher in the unpolluted site. Species diversity tended to decrease with increasing Pb levels in soil although no statistical significance was obtained. No trend was shown between species diversity and Cd levels in soil. The community structure of ground-dwelling spiders was similar for the two types of sites. Overall ground-dwelling spider communities may be not sensitive enough to discriminate moderate heavy metal contamination levels in soil. However, among the dominant spider families, the composition and structure of Linyphiidae separated unpolluted and moderately polluted sites. Pardosa astrigera and P. laura (Lycosidae) have a potential as heavy metal accumulator indicator species and Oedothorax insulanus (Linyphiidae) has a potential as a heavy metal sentinel indicator species.
Show more [+] Less [-]Mobility and Availability of Copper in Agricultural Soils Irrigated from Water Treated with Copper Sulfate Algaecide Full text
2008
Salam, D. | El-Fadel, M.
In this paper, downward movement and availability of copper in soils irrigated with CuSO₄ algaecide treated water were examined using column leaching experiments. Two simulations considering 1 and 10 years irrigation period were conducted at copper application rate of about 18.7 kg CuSO₄/ha/year. Effluent copper concentrations and vertical distribution of acid and DTPA-extractable copper in the soil columns were determined. Nearly 99% of the applied copper was retained in the soil with a C e/C ₀ values on the order of 10⁻³. Retention profiles showed that copper was retained in the upper 2 to 3 cm of the soil. However, a significant fraction of the retained copper was detected in available form (DTPA-Cu) suggesting that plants toxicity could be a major limitation for the use of CuSO₄ treatment in irrigation water.
Show more [+] Less [-]Critical loads of sulphur and nitrogen for terrestrial ecosystems in Europe and Northern Asia influenced by different soil chemical criteria.
2008
Reinds, G.J. | Posch, M. | Vries, de, W. | Slootweg, J. | Hettelingh, J.P.
A critical load data base was developed for Europe and Northern Asia using the latest data bases on soils, vegetation, climate and forest growth. Critical loads for acidity and nutrient nitrogen for terrestrial ecosystems were computed with the Simple Mass Balance model. The resulting critical loads are in accordance with critical loads from previous global empirical studies, but have a much higher spatial resolution. Critical loads of acidity are sensitive to both the chemical criterion and the critical limit chosen. Therefore a sensitivity analysis of critical loads was performed by employing different chemical criteria. A critical limit based on an acid neutralizing capacity (ANC) of zero resulted in critical loads that protect ecosystems against toxic concentrations of aluminium and unfavourable Al/Bc ratios, suggesting that ANC could be an alternative to the commonly used Al/Bc ratio. Critical loads of nutrient nitrogen are sensitive to the specified critical nitrate concentration, especially in areas with a high precipitation surplus. If limits of 3¿6 mg N l¿1 are used for Western Europe instead of the widely used 0.2 mg N l¿1, critical loads double on average. In low precipitation areas, the increase is less than 50%. The strong dependence on precipitation surplus is a consequence of the simple modelling approach. Future models should explore other nitrogen parameters (such as nitrogen availability) instead of leaching as the factor influencing vegetation changes in terrestrial ecosystems.
Show more [+] Less [-]Comparison of Microscopic and Macroscopic Modeling Approaches for Subsurface Contaminant Transport Full text
2008
Bagtzoglou, Amvrossios C | Kim, Daehyun (Don)
The practice of contaminant transport and remediation has shown significant progress in recent years. However, despite the significant progress made, remediation efforts are often delayed by extremely long breakthrough curve tails that render efforts to bring the level of contaminants below the regulatory standards inefficient. One hypothesis is that these long tails are due to the reservoir-like slow diffusive processes in soil micropore zones. This study compares the effects of micropores at macroscopic and microscopic levels and establishes a link between these approaches for validation and calibration purposes. The link between macroscopic and microscopic levels is established through comparisons and testing of the two models while incorporating appropriate scale and boundary effects. Despite the differences in conceptual approaches and simulation time, the two approaches rendered meaningful results. The link helps forecast the effects of micropore zone transport processes in the subsurface efficiently and thus allows development of numerical tools that could contribute towards more efficient remediation design.
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