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Assessing Storm Water Detention Systems Treating Road Runoff with an Artificial Neural Network Predicting Fecal Indicator Organisms
2010
Kazemi Yazdi, S. | Scholz, M.
This paper examines whether multiple regression analysis and neural network models can be applied successfully for the indirect prediction of the runoff treatment performance with water quality indicator variables in an experimental storm water detention system rig. Five biologically mature experimental storm water detention systems with different designs treating concentrated gully pot liquor (spiked with dog droppings) were assessed. The systems were located on The King's Buildings campus at The University of Edinburgh and were monitored for a period of 18 months. Multiple regression analyses indicated a relatively successful prediction of the biochemical oxygen demand and total suspended solids for most systems, but due to a relatively weak correlation between the predictors and both microbial indicators, multiple regression analyses were not applied for the prediction of intestinal enterococci and total coliform colony-forming units. However, artificial neural network models predicted microbial counts relatively well for most detention systems.
Show more [+] Less [-]Effects of Alkalization of the Environment on the Anatomy of Scots Pine (Pinus sylvestris) Needles
2010
Lukjanova, Aljona | Mandre, Malle
The effects of alkaline dust emitted from a cement plant for over 40 years on the anatomy of needles of Scots pine and lignin accumulation were analysed. Comparative analytical studies were conducted in stands similar as to their silvicultural indicators, climate and age in alkalised and in a relatively unpolluted area. Cross-section of needles were stained, photographed under microscope and measured. It was found that, due to the alkalisation of the environment, the total area of the needle cross-section, needle width and thickness and the area of mesophyll had decreased. At the same time, the vascular bundles and epidermis had increased. The greatest anatomical and biochemical differences between the needles from trees growing under optimum conditions and in the alkalised area were observed in the oldest needles. Visual analysis of cross-sections and biochemical analysis showed accumulation of lignin in older needles but more intensively in alkalised areas than in control.
Show more [+] Less [-]An Experimental Study of the Diesel Biodegradation Effects on Soil Biogeophysical Parameters
2010
Martinho, E. | Abreu, M. M. | Pampulha, M. E. | Alegria, F. | Oliveira, A. | Almeida, F.
The purpose of this study was to understand the dynamic conditions of soil/organic mixtures in order to contribute to the study of remediation processes at hydrocarbon spill sites. Induced polarization (IP) and physical, chemical, and microbiological parameters for uncontaminated and artificially contaminated soil samples with diesel oil were evaluated under controlled conditions (constant temperature and soil moisture) during a period of 12 months. In contaminated samples, the resistivity and IP parameters (chargeability and polarizability) decreased during 8 months and remained relatively stable between 8 and 12 months. The observed reduction on resistivity and IP parameters was related to the increase on the granular aggregation of the soil and a decrease on total porosity, caused by diesel-degrading microorganisms. The behavior of the IP parameters observed after 8 months can be explained by a reduction in the microbial activity and, consequently, a decrease of the degradation rate of diesel. In the studied loamy soil with high content of organic matter (96.16 g/kg), the results demonstrate that IP time domain measurements can be used in the evaluation of the evolution of the hydrocarbon degradation even when the concentration is not very high.
Show more [+] Less [-]Rural O₃ Levels in the Middle Ebro Basin During the Plant Growing Season
2010
Gonzalez, Laura | Bermejo, Raúl | Parra, María Asunción | Elustondo, David | Garrigó, Jordi | Santamaría, Jesús Miguel
Ground-level dynamics of O₃, NO x and benzene, toluene, ethylbenzene and xylenes were characterised at rural sites in the medium Ebro River Basin (Northern Spain) from April to September (2003-2007) and by means of automated and passive monitoring. The study registered high O₃ levels within the area, which were influenced by traffic emissions, and a monthly evolution of these levels consistent with the occurrence of a broad summer maximum, typical of polluted areas. The mean ozone concentration registered in the studied area by means of passive sampling was 87 ± 12 μg m⁻³. The 2008/50/EC objective value for the protection of vegetation was widely exceeded during this study (AOT40 = 57,147 ± 14,114 μg m⁻³ h), suggesting that current ambient levels may pose a risk for crops and vegetation in this important agroindustrial region.
Show more [+] Less [-]Biological and Artificial Matrixes as PAH Accumulators: An Experimental Comparative Study
2010
Skert, Nicola | Falomo, Jari | Giorgini, Luigi | Acquavita, Alessandro | Capriglia, Lorenzo | Grahonja, Roberto | Miani, Nordio
In order to find out a new effective accumulator of polycyclic aromatic hydrocarbons (PAHs) useful for monitoring studies on a large scale and low costs, the accumulation capacity of both biological and artificial matrixes (mosses and polyester fibers, respectively) has been tested. For this purposes, Hypnum cupressiforme and dacron® were exposed to pollution airborne in two sites located nearby an active iron industry and in center of the town of Trieste, where high PAH pollution spots, due to vehicular traffic, are usually detected. The samplers were exposed in six sampling sessions for 21 days. The results obtained were compared with data collected by active PAH samplers, usually employed for official widespread monitoring. The level of correlation between the data sets was calculated. Furthermore, a repeatability study of data was performed. According to the results, both matrixes are good PAH accumulators, though they show different skills.
Show more [+] Less [-]Origin of Salinity in Groundwater of Neighboring Villages of the Cerro Prieto Geothermal Field
2010
Moncada-Aguilar, Andrés M. | Ramírez Hernández, Jorge | Quintero Núñez, Margarito | Avendaño-Reyes, Leonel
The residual brine of the Cerro Prieto Geothermal Field (CPGF) is disposed in an evaporation pond. The seepage of this pond has contaminated the water and agricultural soil around it. The contamination of the groundwater towards the southwest by the evaporation pond, in the direction of the regional flow, has been shown before. Hydrogeochemical modeling (PHREEQCI) and Schoeller and Piper diagrams have been used in this work to show that the chemical composition of the groundwater in villages neighboring CPGF is the product of mixing between irrigation water from the Colorado River and brine from the evaporation pond. The high potassium concentration in the water and the relative increase in concentration of sodium and chlorides along the flow path as well as the hydrogeochemical models for this system explain this mixing process. This work will allow proposing new managing techniques to avoid the presence of the residual brine in the groundwater of agricultural lands.
Show more [+] Less [-]Trace Analysis of N-Nitrosamines in Water Using Solid-Phase Microextraction Coupled with Gas Chromatograph-Tandem Mass Spectrometry
2010
Hung, Hsu-Wen | Lin, Tsair-Fuh | Chiu, Chuen-Huey | Chang, Ya-Chi | Hsieh, Tung-Ying
A method that utilizes solid-phase microextraction (SPME) coupled with gas chromatography (GC) and chemical ionization tandem mass spectrometry (MS/MS) was developed for analyzing a group of emerging pollutants, N-nitrosamines, in water. The developed analytical method requires a water sample of less than 5 ml and only 1.5 h for complete analysis. The method detection limits for N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine, and N-nitrosodi-n-propylamine were in the range of 3.2 to 3.5 ng/l; for N-nitrosomorpholine, it was 15.2 ng/l. The method was successfully employed to measure the N-nitrosamine concentration at trace levels of nanogram per liter in four water treatment plants (WTPs) and one water distribution system. In the WTPs, only NDMA was detected in the treatment processes. Within the treatment train, NDMA was observed after chlorination. The level of NDMA significantly declined after slow sand filtration due presumably to microbial degradation. The NDMA concentration collected from consumer tap water was about 40% higher on average than that in the finished water. The excellent performance of the SPME/GC/MS/MS method in various water matrices as well as the shorter analysis time and smaller sample volume compared to currently used extraction techniques makes it an alternative means for the analysis of N-nitrosamine in drinking water, wastewater, and laboratory research with small reactors.
Show more [+] Less [-]Evaluating the Potential of Forest Species Under “Microbial Management” for the Restoration of Degraded Mining Areas
2010
Mendes Filho, P. F. | Vasconcellos, R. L. F. | de Paula, A. M. | Cardoso, E. J. B. N.
The increasing number of degraded soil areas caused by open cast mining activities has brought about a critical damage to the environment. The mine spoil must be ameliorated with anthropogenic interferences which consist of revegetating soils after organic matter amendment and provision of microbial diversity, to guarantee basic conditions for a sustainable soil biological activity. Five woody species, Acacia mangium Willd., Inga edulis Mart., Mimosa caesalpiniaefolia Benth, Parkia multijuga Benth., and Schinus terebinthifolia Schlecht. & Cham were cultivated under greenhouse conditions to evaluate the potential of plant establishment on cassiterite mining waste, considering the contribution of mycorrhizal fungi inoculation, organic compost, and thermophosphate amendment. The shoot height, dry weight, and nitrogen and phosphorus shoot contents were determined. Three species of nodulating legumes, A. mangium, M. caesalpiniaefolia, and S. terebinthifolia showed a great positive response to organic compost, termophosphate, and mycorrhizal inoculation, increasing the plant height and the shoot dry weight. Plants inoculated with arbuscular mycorrhizal fungi and fertilized with organic compost also increased their nitrogen and phosphorus shoot contents. The addition of organic compost and mycorrhizal fungi were essential for plant development and the reforestation of mining areas should be initiated with mycotrophic and nodulating legumes.
Show more [+] Less [-]Surface Water Quality as Affected by Sugarcane Residue Management Techniques
2010
Udeigwe, Theophilus K. | Wang, Jim J. | Viator, Howard P. | Gaston, Lewis
This study evaluated the impacts of three sugarcane residue management techniques, namely postharvest burning of residue (BR), shredding of residue (SR), and full postharvest retention of residue (RR), on the water quality of surface runoff from February 2006 to September 2007 in Iberia, LA. Total runoff volumes recorded were 58,418, 57,923, and 46,578 L for the BR, SR, and RR treatments, respectively. Except for total Kjeldahl nitrogen (TKN), which was higher for BR than RR or SR, there were no significant differences in total loads of total suspended solids (TSS), total dissolved solids (TDS), biological oxygen demand at 5 days (BOD₅), total phosphorus (TP), nitrate-N, nitrite-N, and sulfate among the three residue management techniques, although the RR treatment generally exported the lowest total loads. Regression analyses on the pollutant load and rainfall event showed that the load exported for each water quality parameter was positively correlated with precipitation, with the BR treatment being more sensitive to rainfall amount than the RR and SR treatments in TSS, TKN, TP, BOD, nitrate, and sulfate exports. Runoff TSS and turbidity were also highly correlated (R ² = 0.95, P < 0.001). The results suggested that the two sugarcane residue retention practices (RR and SR) had limited benefit on improving surface runoff water quality over the BR practice in subtropical region such as Louisiana.
Show more [+] Less [-]Evaluating Binary Sorption of Phenol/Aniline fromAqueous Solutions onto Granular Activated Carbon and Hypercrosslinked Polymeric Resin (MN200)
2010
Valderrama, César | Barios, Joan I. | Farran, Adriana | Cortina, Jose Luis
Sorption equilibrium of phenol and aniline onto the granular activated carbon and hyperreticulated un-functionalized polymeric resin (MN200) was investigated in single and binary component aqueous systems. Higher loading was obtained for aniline than phenol onto both sorbents, which is probably due to hydrophobic difference between both solutes and the greater electronic density of the aromatic ring of the aniline. Granular activated carbon reported larger uptake than resin MN200 for both solutes, which may be attributed to the better physical properties of the granular activated carbon, for instance, larger surface area. The experimental sorption could be properly described by the Langmuir and Freundlich isotherms. Five models for predicting the binary equilibrium sorption isotherm were compared in order to determine the best fit model to correlate binary experimental data: the extended Langmuir isotherm with and without a constant interaction factor, a simplified model based on the single equilibrium factors, the empirical extended Freundlich isotherm and the modified extended Langmuir equation, which considers the synergistic interactions between sorbate-sorbate and not only the competition between them defined by the extended Langmuir model. The modified extended Langmuir model provides the best agreement between predicted and experimental data indicating that the synergistic interactions between solutes play an important role in the binary phenol/aniline sorption system.
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