Spatial distribution of arsenic in the intertidal sediments of River Scheldt, Belgium

A study was carried out to assess the spatial distribution of arsenic in the intertidal sediments of the River Scheldt in Belgium. Sediment samples were collected from different locations along the River Scheldt up to 100 cm depth and analysed for the major physicochemical properties. The study reveals that the arsenic contents in the sediment samples vary in a wide range, from 2.3 to 140.2 mg kg(-1) dry weight. Moreover, the arsenic concentrations are generally below the background concentrations and remediation thresholds of arsenic in Flanders, Belgium. The occurrence of arsenic is found closely related to some physicochemical properties of the sediments. Arsenic has a strong positive correlation with organic matter and clay contents. On the contrary, a negative correlation exists between arsenic, sand and pH. It is recommended to develop and use organic matter control practices for lowering further accumulation of arsenic within the sediments.     

Coastal Langmuir circulations induce phase-locked modulation of bathymetric stress

Environmental Fluid Mechanics - The ocean boundary layer (OBL) is forced by atmosphere-ocean and sea ice-ocean momentum fluxes, wave dynamics, and buoyancy; in coastal zones, OBL dynamics are...     

Institutional development for sustainable rangeland resource and ecosystem management in mountainous areas of northern Nepal

Rangelands represent one of the most important natural resources in mountainous regions of northern Nepal. However, a poor understanding of the social dimensions of rangeland use has limited their proper management and sustainable development, which represent major challenges for Nepal's resource managers. Institutional development is thought to be a viable solution to this problem and may ultimately lead to improved rangeland management in Nepal. Based on this hypothesis, a study was conduced in the Rasuwa district of northern Nepal to examine the effectiveness of institutional development at the local and national levels in mitigating the problems facing sustainable rangeland management by using an institutional analysis and development (IAD) framework. The information and data were mainly collected from different stakeholders, farmers, professionals and practitioners using a toolkit of participatory rural appraisal (PRA), workshops and literature review. It can be concluded from this case study that a number of institutional development efforts are needed to promote sustainable rangeland management in this region. First, local herders represent a repository of rich indigenous knowledge essential to sustaining sound rangeland management practices; hence, indigenous practices need to be integrated into modern technologies. Second, public services and technical support are currently unavailable or inaccessible to local herders; hence, research, development and extension interventions need to be initiated for marginalized pastoral communities. Third, rangeland institutions are incomplete and ill-organized, so institutional development of various organizations is necessary for promoting sustainable rangeland management. Fourth, the policies and governance necessary for promoting rangeland management are not well-designed; hence, governance reform and policy development need to be formulated through internal and external agencies and organizations.     

Aliphatic–Aromatic Polyols by Thiol–Ene Reactions

Aliphatic–aromatic polyols were synthesized by thiol–ene reactions (photochemical or thermal) using mercaptanized starting materials from bio-based compounds: limonene dimercaptan, thioglycerol, mercaptanized castor oil and isosorbide (3-mercaptopropyl) ether. Aromatic starting materials were phenols containing double bonds; ortho-allyl phenol (OAP, petrochemical-based) and eugenol (EUG, bio-based). The phenolic hydroxyl groups were blocked by alkoxylation with propylene oxide (PO) or glycidol (GLY) prior to use in thiol–ene reaction. The aromatic rings were attached to the mercaptans by reacting thiol groups with the double bonds of alkoxylated OAP (OAP–PO and OAP–GLY) and alkoxylated EUG (EUG–PO and EUG–GLY). These synthesized aliphatic–aromatic polyols were utilized for preparation of rigid polyurethane foams whose physical–mechanical properties were superior to those made only from bio-based aliphatic polyols. These rigid PU foams can be used in a wide range of applications; such as thermal insulation of freezers, buildings, pipes and storage tanks for food and chemical industries, as wood substitute, packaging materials and flotation materials.     

Total mercury status in an urban water body,Mithi River,Mumbai and analysis of the relation between total mercury and other pollution parameters

Mercury is a heavy metal which has garnered attention recently in India. Minamata Convention on mercury was established on October 2013 and was joined by India on September 30, 2014. India is seen as a major mercury pollution source after China according to many studies in the past. Various mercury pollution sites that are currently recognized in India are Kodai Lake, Kodaikanal, Tamil Nadu, and Thane Creek, Mumbai. Since 1992, chlor-alkali plants have been regulated to eliminate mercury cell process of manufacturing. Also, medical and health care facilities are discarding mercury-containing equipment and processes. Various anthropogenic sources of mercury to the atmosphere include combustion of fossil fuels, processing and mining of primary metal ores, cement manufacturing units, chlor-alkali plants, and use of mercury in various products like paints, electric switches, and relays. The hazard associated with mercury pollution becomes extremely serious when we consider its ability to be transported over long-range distances. Various atmospheric transport models suggest India and other Asian countries to be a major source of long-range transport of mercury to North America. Considering the hazards of mercury and its widespread presence in our life, a study on mercury pollution in an urban water body is conducted. This study deals with Mithi River located in Mumbai Metropolitan Region (19.0760° N, 72.8777° E) to study the total mercury in water and derive its relationship with other pollution parameters.     

Gaining forests but losing ground: A GIS evaluation in a Himalayan watershed

GIS overlay techniques were used to provide a quantitative historic documentation of deforestation and land-use dynamics in the Middle Mountains of Nepal between 1947 and 1990. Deforestation was most critical in the 1960s, but active afforestation programs in the 1980s have reversed the process. In spite of these trends, the degradation problem is more complex. The GIS evaluation showed that 86% of the recently afforested land is now under pine plantations located primarily at lower elevations and moderately steep slopes. In contrast, rainfed agricultural expansion is most pronounced on acidic soils and steeper, upper elevation sites, suggesting marginalization of agriculture. Agricultural expansion coupled with major losses of grazing land to pine forests are the key processes pointing towards major animal feed deficits. An alternative animal feed source is suggested through GIS using a topographically based microclimatic classification to generate a tree-planting map where the optimum ecological conditions for selective native fodder tree species are identified.     

General equilibrium effects of a supply side GHG mitigation option under the Clean Development Mechanism

The Clean Development Mechanism (CDM) under the Kyoto Protocol to the United Nations Framework Convention on Climate Change is considered a key instrument to encourage developing countries' participation in the mitigation of global climate change. Reduction of greenhouse gas (GHG) emissions through the energy supply and demand side activities are the main options to be implemented under the CDM. This paper analyses the general equilibrium effects of a supply side GHG mitigation option-the substitution of thermal power with hydropower--in Thailand under the CDM. A static multi-sector general equilibrium model has been developed for the purpose of this study. The key finding of the study is that the substitution of electricity generation from thermal power plants with that from hydropower plants would increase economic welfare in Thailand. The supply side option would, however, adversely affect the gross domestic product (GDP) and the trade balance. The percentage changes in economic welfare, GDP and trade balance increase with the level of substitution and the price of certified emission reduction (CER) units.     

Valuing nature-based recreation in public natural areas of the Apalachicola River region, Florida

As more people visit natural areas for tourism and recreation purposes, it is becoming increasingly important to understand the value they place on these natural resources. Specifically, tourists to Florida have been increasingly interested in visiting natural areas, forests, parks, and preserves-highlighting the importance of this new and growing phenomenon. We analyze visitors' demand for nature-based recreation in the Apalachicola River region of Florida using the travel cost method. The results from a count data regression model reveal that on average visitors would pay 74.18 dollars per visit-day for nature-based recreation resulting in a total economic value of 484.56 million dollars attributable to nature-based recreation in the Apalachicola River region. Results of this study provide useful information for natural resources management in the region and a rationale to preserve Florida's unique ecosystems.     

Soil carbon and nitrogen in 28-year-old land uses in reclaimed coal mine soils of Ohio

Carbon (C) and nitrogen (N) play an important role in the restoration of ecosystem functions of reclaimed mine soils (RMSs). Postreclamation land use in RMSs affects soil C and N pools and fluxes. We compared the effects of 28-yr-old postreclamation land uses (forest, hay, and pasture) on selected chemical properties of soil, and C and N pools in reference to undisturbed forest and moderately disturbed agricultural land use in southeastern Ohio. The electrical conductivity was higher in RMSs under hay than that in pasture and forest land uses. The RMSs under pasture, hay, and forest had moderately acidic, neutral to slightly alkaline, and slightly alkaline pH, respectively. In the 0- to 5-cm soil depth, soil organic C (SOC) was higher in RMSs under pasture by 99% and under hay by 52% over that under forest. Similarly, total nitrogen (TN) was higher in RMSs under pasture by 98% and under hay by 43% over that under forest. Aggregate-associated SOC concentration in the 0- to 5-cm depth decreased in the order of RMSs under hay > RMSs under pasture > RMSs under forest. The SOC pools in the 0- to 30-cm depth decreased in the order of RMSs under hay = RMSs under pasture > RMSs under forest = undisturbed forest = agriculture land use. Nitrogen pools followed a similar trend. Hay land use has a better potential for improving soil quality in RMSs by enhancing chemical properties and SOC and TN pools than forest or pasture land uses.