CHANNELIZATION EFFECTS ON OBION RIVER FLOODING,WESTERN TENNESSEE1

ABSTRACT: Much of the Obion River in western Tennessee was channelized into the 1960s. Stage data from three stream-flow gaging stations on the Obion were used to determine how channelization affected flood frequency and annual maximum stage. Channelization affected the upper and lower Obion River differently. Flooding has become infrequent on the upper Obion River since channelization, even during the winter and spring which is the wettest time of year. In contrast, except for the winter months, there has been little effect on flood frequency on the lower Obion River where stage is highly dependent on the Mississippi River. The Mississippi River often backs up and floods the Obion River more than 50 km above its mouth and may contribute to flooding at an even greater distance upstream by reducing the water-surface gradient and slowing discharge. Channelization on the upper section of the river and many of the small tributaries has increased flow efficiency, but has also caused channel erosion and downstream deposition, reducing the cross-sectional channel area and possibly contributing to downstream flooding. Maximum annual stages at the upper and lower Obion River changed little. Therefore, the maximum surface area, submerged at least once each year, has been unaffected by channelization.     

A technicoeconomic approach for the selection of a site remediation strategy--part B: model application

Different tools, such as a screening matrix or decision framework, are available to select a remediation technology to treat a contaminated site. However, unless these methods can point out the appropriate technology in regards to the decision-maker's knowledge about the contaminated site, they are less useful to evaluate both the technical effectiveness and the cost of the remediation, and to assess different remediation strategies from either future data acquisition or the use of an irreversible remediation technology. A model developed to allow such evaluations has been used to simulate the remediation of a virtual contaminated site. From this, four remediation recommendations have been made. These recommendations are guidelines for the build up of a remediation strategy that would both maximize the effectiveness of the decontamination and minimize its total cost.     

Quantitative analyses of selected polychlorinated biphenyl (PCB) congeners in water,soil, and sediment during winter and spring seasons from Msunduzi River,South Africa

The lack of information and the need for knowledge on the organic pollutants within the area of KwaZulu-Natal together with the global problem of water supply have prompted our investigation into the analyses of eight polychlorinated biphenyl (PCB) congeners in the Msunduzi River of KwaZulu-Natal, South Africa. Soil, sediment, and water samples were collected at ten different sites along the river during winter and spring seasons. Soil and sediment samples were extracted using ultra sonication with dichloromethane while water samples were liquid-liquid extracted using dichloromethane. All sample extracts were cleaned-up using a multi-layer silica gel column and analyzed with gas chromatography-mass spectrometry. Quality assurance measures were also determined. The percentage recoveries for water were 53–128 for all the PCBs analyzed, while sediment recoveries ranged between 69 and 105%. The highest total concentrations of the PCBs in sediment were 214.21–610.45 ng/g dw at the Du Toit sampling site and 30.86–444.43 ng/g dw basis at the wastewater treatment inlet for winter and spring, respectively. Soil PCB concentrations were 76.53–397.75 ng/g dw at the Msunduzi Town sampling site and 20.84–443.49 ng/g (dry weight) at the Du Toit sampling site for winter and spring, respectively. In addition, high PCB concentrations were found in effluent of the wastewater treatment inlet compared to other sampling sites, which ranged between 0.68–22.37 and 2.53–35.69 ng/mL for winter and spring seasons, respectively. In all the sampling sites selected for this study, Du Toit afforded the highest PCB concentration levels and the lowest was after chlorination at the Darvill wastewater treatment plant. The results presented are new and it is the first study of organic pollutants such as PCBs that has been carried out on this river.     

The potential of biomonitoring of air quality using leaf characteristics of white willow (Salix alba L.)

In this study, we assess the potential of white willow (Salix alba L.) as bioindicator for monitoring of air quality. Therefore, shoot biomass, specific leaf area, stomatal density, stomatal pore surface, and stomatal resistance were assessed from leaves of stem cuttings. The stem cuttings were introduced in two regions in Belgium with a relatively high and a relatively low level of air pollution, i.e., Antwerp city and Zoersel, respectively. In each of these regions, nine sampling points were selected. At each sampling point, three stem cuttings of white willow were planted in potting soil. Shoot biomass and specific leaf area were not significantly different between Antwerp city and Zoersel. Microclimatic differences between the sampling points may have been more important to plant growth than differences in air quality. However, stomatal pore surface and stomatal resistance of white willow were significantly different between Zoersel and Antwerp city. Stomatal pore surface was 20% lower in Antwerp city due to a significant reduction in both stomatal length (?11%) and stomatal width (?14%). Stomatal resistance at the adaxial leaf surface was 17% higher in Antwerp city because of the reduction in stomatal pore surface. Based on these results, we conclude that stomatal characteristics of white willow are potentially useful indicators for air quality.     

Prioritisation of native legume species for further evaluation as potential forage crops in water-limited agricultural systems in South Africa

In the face of climate change, identification of forage species suitable for dryland farming under low rainfall conditions in South Africa is needed. Currently, there are only a limited number of forage species suitable for dryland farming under such conditions. The objective of this study was to identify and prioritise native legume species that could potentially be used in dryland farming systems in water-limited agro-ecosystems in South Africa. Using a combination of ecological niche modelling techniques, plant functional traits, and indigenous knowledge, 18 perennial herbaceous or stem-woody legume species were prioritised for further evaluation as potential fodder species within water-limited agricultural areas. These species will be evaluated further for their forage quality and their ability to survive and produce enough biomass under water limitation and poor edaphic conditions.     

Indoor airborne fungal pollution in newborn units in Turkey

Pathogenic and/or opportunistic fungal species are major causes of nosocomial infections, especially in controlled environments where immunocompromised patients are hospitalized. Indoor fungal contamination in hospital air is associated with a wide range of adverse health effects. Regular determination of fungal spore counts in controlled hospital environments may help reduce the risk of fungal infections. Because infants have inchoate immune systems, they are given immunocompromised patient status. The aim of the present study was to evaluate culturable airborne fungi in the air of hospital newborn units in the Thrace, Marmara, Aegean, and Central Anatolia regions of Turkey. A total of 108 air samples were collected seasonally from newborn units in July 2012, October 2012, January 2013, and April 2013 by using an air sampler and dichloran 18% glycerol agar (DG18) as isolation media. We obtained 2593 fungal colonies comprising 370 fungal isolates representing 109 species of 28 genera, which were identified through multi-loci gene sequencing. Penicillium, Aspergillus, Cladosporium, Talaromyces, and Alternaria were the most abundant genera identified (35.14, 25.40, 17.57, 2.70, and 6.22% of the total, respectively).     

Consequence of altered nitrogen cycles in the coupled human and ecological system under changing climate: The need for long-term and site-based research

Anthropogenically derived nitrogen (N) has a central role in global environmental changes, including climate change, biodiversity loss, air pollution, greenhouse gas emission, water pollution, as well as food production and human health. Current understanding of the biogeochemical processes that govern the N cycle in coupled human–ecological systems around the globe is drawn largely from the long-term ecological monitoring and experimental studies. Here, we review spatial and temporal patterns and trends in reactive N emissions, and the interactions between N and other important elements that dictate their delivery from terrestrial to aquatic ecosystems, and the impacts of N on biodiversity and human society. Integrated international and long-term collaborative studies covering research gaps will reduce uncertainties and promote further understanding of the nitrogen cycle in various ecosystems.     

Domestic energy usage and its' health implications on residents of the Ese‐Odo and Okitipupa local government areas of Ondo state,Nigeria

This study examined domestic energy usage and its health implication on residents of Ese‐Odo and Okitipupa Local Government Areas (LGA), of Ondo State. Systematic random sampling was used to select 103 and 156 respondents in Ese‐Odo and Okitipupa LGA, respectively. It was established that environmental and socio‐economic related attributes influenced residents' choice of domestic energy type. Similarly, burns, blindness, stroke, cataract and pulmonary diseases were the most prevalent self‐reported ill‐health. A relatively weak correlation between domestic energy usage and ill‐health is experienced by the residents. Therefore, the study concluded that the use of traditional energy types had significant adverse effects on the health of the residents in Okitipupa and Ese‐Odo LGAs of Ondo State.     

Implications of choices and interpretation in LCA for multi-criteria process design: de-inked pulp capacity and cogeneration at a paper mill case study

Retrofit process design can be seen as a multi-criteria decision-making (MCDM) problem aiming at selecting the best alternative for improving the performance of a chemical process. There is a growing consensus that environmental considerations, including the environmental impact associated with all life cycle stages of materials, should be integrated in chemical process design. Life cycle assessment (LCA) is a technique that allows quantification of those impacts. However, implementing this technique would increase the decision-making complexity and thus would necessitate systematic tools and methods. The analogy between LCA and MCDM has been recognized, but the systematic evaluation of LCA methodological choices and interpretation in this context is rarely discussed. The importance of those is demonstrated in this paper using a case study involving the implementation of de-inked pulp capacity and cogeneration and an integrated newsprint mill.