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Small-scale constructed wetlands for onsite treatment of household wastewater in Belgium Full text
2006
Xanthoulis, Dimitri | Fonder, N. | Wauthelet, M.
peer reviewed
Show more [+] Less [-]The ecology of transportation
2006
Davenport, J. (John) | Davenport, Julia L.
Human transport by land, sea and air has increased exponentially through time in intensity, paralleling rises in population, prosperity and rates of technological change. Transport has considerable ecological effects, many of them detrimental to environmental sustainability. This volume brings together international experts from a variety of disciplines to review the ecological effects and their causes in terms of road, rail, ship and aircraft transport. The contributors have different attitudes and agendas. Some are ecologists, some planners, others social scientists. Focus ranges from identification of threats and amelioration of damaging effects through to future design of transport systems to minimize environmental degradation. Some chapters consider restricted areas of the globe; others the globe itself. Views encompass deep pessimism and cautious optimism. Uniquely, the volume considers transport effects in all environments. This is the first book that attempts to discuss the relationship between human transport and all ecosystems. It appeals not only to the specialist environmentalist by picking out novel topics, but also to anyone involved in transport issues as it tackles the issues from an historical perspective, encompassing the past, present and future of the effects of human transport.
Show more [+] Less [-]The Fernow watershed acidification study
2006
Adams, Mary Beth | DeWalle, David R. | Hom, John Lun
Focus on water pollution research
2006
Livingston, James V.
Microbially Mediated Redox Cycling at the Oxic-Anoxic Boundary in Sediments: Comparison of Animal and Plants Habitats Full text
2006
Hines, Mark E
Microorganisms are responsible for the bulk of transformations that occur in surficial sediments. They are most active at redox boundaries where they can benefit from access to various oxidants and reductants generated during redox cycling events. To illustrate the dynamics of microbially mediated processes, especially those involving sulfur and metal cycles, processes were compared in habitats either bioturbated by a capitellid worm or inhabited by a salt marsh grass. The presence of macrofauna and macroflora greatly altered the three-dimensional array of redox gradients in sediments, but the type and form of reductants and oxidants provided varied greatly; clastic sedimentary infauna subducted solid phase organic material and iron oxides, whereas plant roots released dissolved organic matter and oxygen. These differences resulted in a bioturbated system that exhibited a rapid sulfur cycle (residence time of minutes), but a slower iron cycle (days), whereas vegetation caused a slow sulfur cycle and rapid iron cycle. Alteration of sediments by higher life forms also greatly affected the composition and relative abundances of sedimentary bacteria, even on short time scales. Although redox cycling at interfaces can be somewhat predictable, variations in response to biological and physical perturbations demonstrated wide differences in the dynamics of redox-mediated processes.
Show more [+] Less [-]Effect of Sediment Humic Substances on Sorption of Selected Endocrine Disruptors Full text
2006
Sun, W. L | Ni, J. R | Liu, T. T
Characterizing sorption processes is essential to understand the environmental distribution and toxicity potential of endocrine disruptors in terrestrial and aquatic systems. The sorption behaviors of three endocrine disruptors (bisphenol A (BPA), 17β-estradiol (E2), and 17α-ethynylestradiol (EE2)) on sediments were investigated using batch techniques. Samples were taken from some representative reaches in several major Chinese rivers. More attention has been paid to the effect of sediment organic components on the sorption of BPA, E2, and EE2. The results show that the sediment organic carbon-normalized partition coefficients (K oc (sed)) for three endocrine disruptors are in the order of EE2 > E2 > BPA, which corresponds to the octanol-water partitioning coefficients (logK ow) of the compounds. Moreover, the K oc values for humic substances (K oc (hs)) are comparable with the K oc (sed) values and highly dependent on the physico-chemical properties of humic substances in sediments. The UV absorptivity at 272 nm (A ₂₇₂), which suggests the abundance of aromatic rings in humic substance structure, correlates well with the K oc (hs) values. In addition, the infrared spectra of the humic substances extracted from sediments show four strong bands centered at 3,400 cm-¹, 1,625 cm-¹, 1,390 cm-¹, and 1,025 cm-¹. The K oc (hs) values have a positive linear relation with the peak area ratio for peak at 1,025 cm-¹ and a negative linear relation with the peak area ratio between peaks at 1,625 cm-¹ and 1,025 cm-¹. Hence, the hydrogen bonds play a critical role to the sorption of selected endocrine disruptors.
Show more [+] Less [-]Distribution of Redox-sensitive Elements in Bottom Waters, Porewaters and Sediments of Rogoznica Lake (Croatia) in Both Oxic and Anoxic Conditions Full text
2006
Ciglenečki, Irena | Pichler, Srđan | Prohic, Esad | Ćosović, Božena
Geochemical, mineralogical and sedimentological analyses were carried out to contrast two different sites (respectively characterized by permanently oxic and anoxic conditions) in a small, meromictic, seawater lake. In fact, due to relatively high organic matter content, and reduced water exchange, the Rogoznica Lake has almost permanent anoxic conditions below the depth of 12 m, where sediment can be considered an anoxic-sulphidic sedimentary environment. Different water column and sediments redox conditions affect the distribution and speciation of major redox-sensitive metals (Fe, Mn, Mo), reduced sulphur species (RSS) and dissolved organic C (DOC). Trace metals, especially those that accumulate in anoxic-sulphidic environments (Fe, Mo) showed a marked enrichment in the solid phase, whereas the low solubility of sulphides leads to low porewater concentrations. The relatively high sedimentary enrichment of Mo (up to 81 mg/kg) also confirms highly anoxic conditions within the Rogoznica Lake sediments. Results clearly show that chemical species within the sediments will tend towards equilibrium between porewater and solid phase according the prevailing environment conditions such as redox, pH, salinity, DOC.
Show more [+] Less [-]Quantifying Fine-Sediment Sources in Primary and Selectively Logged Rainforest Catchments Using Geochemical Tracers Full text
2006
Blake, W. H | Walsh, R. P. D | Sayer, A. M | Bidin, K
Detailed information on post-logging sediment dynamics in tropical catchments is required for modelling downstream impacts on communities and ecosystems. Sediment tracing methods, which are potentially useful in extending to the large catchment scale and longer time scales, are tested in primary and selectively logged rainforest catchments of Sabah, Borneo. Selected nutrient (P and N) and trace metal (Ni and Zn) concentrations are shown to discriminate surface, shallow subsurface and deep subsurface sediment sources. Analysis of channel-stored fine-sediment samples and use of an unmixing model allow the relative importance of these vertical sediment sources to be estimated and erosion processes to be inferred for catchments of contrasting size.
Show more [+] Less [-]Non-Probabilistic Uncertainty in Subsurface Hydrology and Its Applications: an Overview Full text
2006
Ozbek, Metin M | Pinder, George F
While a presumed equality between uncertainty and probability is dominant in subsurface hydrology, in other areas of science and engineering progress in the mathematics of uncertainty is leading the way in providing new types of uncertainty, distinct from probability. In this paper our focus is on one of these, namely fuzzy set theory and fuzzy logic. We start with an overview of fuzzy theory introducing terminology, notation, and concepts relevant to our paper. We continue our discussion with an overview of currently known applications in several areas that include subsurface characterization, groundwater flow and transport modeling, water resources management and optimization, and groundwater health risk assessment and management.
Show more [+] Less [-]The New Jersey Toxics Reduction Workplan for Ny-Nj Harbor: Distribution of Pcdd/Fs in Ambient Waters Full text
2006
Dimou, K Nadia | Pecchioli, Joel A
As part of the NJ Toxics Reduction Workplan for NY-NJ Harbor, ambient water samples were collected at fifteen locations along the tidal portions of the Hackensack, Passaic, Raritan, Rahway and Elizabeth Rivers, and in Newark Bay, the Arthur Kill, and Kill van Kull. A Trace Organics Platform Sampler was used to collect a total of 75 suspended sediment phase samples between June 2000 and May 2002. These samples were analyzed for spatial and wet vs. dry weather trends in the 17 polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs; modified USEPA Method 1613b). Mean total PCDD/F (tPCDD/F) concentrations at the sampling locations ranged between 3.8 and 41.5 ng/g. On average, OCDD accounted for almost 80% of the tPCDD/F concentrations; mean total [PCDD/F - OCDD] concentrations ranged between 0.84 and 5.20 ng/g at the sampling locations. Mean 2,3,7,8-TCDD concentrations ranged between 0.003 and 0.28 ng/g, with the highest concentrations (> 0.10 ng/g) along the tidal Passaic and lower Hackensack Rivers, and in upper Newark Bay. Mean tPCDD/F Toxic Equivalency Quotients (TEQ) ranged between 45 and 344 TEQ pg/g, with the highest levels found in the lower Passaic River. Toxicity was primarily driven by 2,3,7,8-TCDD concentrations in the Passaic and Hackensack Rivers, and in Newark Bay. Examples of congener distribution patterns at some of the sampling locations are also presented.
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