Trends in Dissolved Gaseous Mercury in the Tahquamenon River Watershed and Nearshore Waters of Whitefish Bay in the Michigan Upper Peninsula

A field study was conducted in June of 1998 to characterize the dynamics of dissolved gaseous mercury (DGM) in the TahquamenonRiver watershed and nearshore waters of Whitefish Bay in the Upper Michigan Peninsula. We found that over a transect acrossthe watershed, DGM levels increased generally from a creek (mean = ～12 pg L^-1), passing through the watershed, to the nearshore surface waters of the bay (mean = ～29 pg L^-1). DGM levels in nearshore surface waters of the bayranged from ～15 to ～50 pg L^-1 and peaked generally around noontime, exhibiting diurnal trends. A significant DGM decline from ～32 pg L^-1 in the early morning to ～15 pg L^-1 during the day was observed in these surface waters following passage of a coldfront, probably caused by wind-induced mixing and decrease insolar radiation associated with the frontal passage.     

Trapping for mink control and water vole survival: Identifying key criteria using a spatially explicit individual based model

Introduced alien species are the second most important threat to global biodiversity after habitat loss. The American mink Mustela vison has been introduced to several countries and is threatening a number of native species worldwide. We developed a spatially explicit and individual based model as a planning tool to identify key criteria for the implementation of trapping campaigns as a way to control open American mink populations. We first predicted the minimum effort required to reduce populations of mink below a certain threshold and the best time of year in which to trap mink to minimise their numbers. We then employed this methodology to predict the best trapping strategy to ensure the long-term survival of the water vole Arvicola terrestris, one of the species most endangered by the spread of the mink in the UK. We also applied the mink and water vole population models to rationalise a set of observed data in an area of 50 × 30 km in the Upper Thames (UK). The model predicted that it is necessary to remove mink for at least 3 months every year and that a mixed strategy of trapping during the mating, late dispersal and winter seasons is best for keeping mink at low densities. Concentrating trapping during the late dispersal and winter seasons is instead best for ensuring the long-term survival of water voles. Targeting immigrating juvenile mink as well as reproductive adults is important. The model also showed that trapping efficiency might be an important factor to consider when choosing periods in which to trap.     

Long-term continuous cropping in the Pacific Northwest: Tillage and fertilizer effects on winter wheat, spring wheat, and spring barley production

Conventional tillage winter wheat (Triticum aestivum) (WW)–summer fallow reduces soil productivity and increases soil erosion. Conservation tillage management, together with intensive cropping may have the potential to reverse these sustainability concerns. The objective of this study was to determine the effects of conventional tillage (CT) and no-tillage (NT) systems on grain yield of long-term annual cropping of monoculture WW, spring wheat (SW), and spring barley (Hordeum vulgare) (SB) grown with or without fertilizer, in the Pacific Northwest region of the USA. In unfertilized crops, grain yield of WW, SW, and SB was 15%, 25%, and 50% higher, respectively, in CT than in NT plots, an indication of the involvement of yield limiting factors under the NT cropping system. When fertilized, there were no significant differences in grain yield of WW. Yields of SW and SB, however, remained 21% and 15% higher, respectively, in CT than in NT, an indication that factors other than fertility were involved. These results suggest that in order for NT management to be widely adopted by area growers, the yield-limiting factors need to be addressed.     

Extraction and characterization of Foeniculum vulgare pectins and their use for preparing biopolymer films in the presence of phaseolin protein

Pectins from Foeniculum vulgare were extracted under acidic conditions. The obtained pectins were mainly composed of uronic acid but also contained traces of rhamnose, galactose, and arabinose. Extracted pectins were used as a carbohydrate source to prepare biopolymer films in the absence and in the presence of phaseolin protein. The swelling characteristics of the films were examined as a function of ionic strength, pH, and the applied osmotic stress. The swelling behavior was dominated by a Donnan-type effect, which decreases with increasing ionic strength and counterion valency. In all cases the swelling of films containing phaseolin was reduced, suggesting a network formation between protein and pectins. Mechanical property studies have also estimated the validity of the obtained novel biopolymer films in terms of mechanical resistance.     

An Assessment of Mercury in the Form of Amalgam in Dental Wastewater in the United States

An assessment was conducted of the discharge from dental facilities of mercury in the form of amalgam to surface waters in the United States. Two pathways were examined – effluent from publicly owned treatment works (POTWs) and air emissions from sewage sludge incinerators (SSIs). The annual use of mercury in the form of amalgam in the U.S. is approximately 35.2 tons (31.9 metric tons). It was estimated that 29.7 tons (26.9 metric tons) of mercury in the form of amalgam are annually discharged to the internal wastewater systems of dental facilities during amalgam placements and removals. Based on the partial capture of this amalgam in conventional chair-side traps and vacuum filters, the discharge of mercury in the form of amalgam from dental facilities to POTWs was estimated to be 6.5 tons (5.9 metric tons). The discharge of mercury to surface water via POTW effluents and SSI emissions was estimated to total approximately 0.4 tons (0.4 metric tons). A cost-effectiveness analysis determined that the annual cost to the dental industry to reduce mercury discharges through the use of amalgam separators would range from 380 millionto 1.14 billion per ton.     

Identification of three triterpenoids in almond hulls

Three triterpenoids, betulinic acid, oleanolic acid, and ursolic acid, were isolated as their methyl esters (treatment with diazomethane) from diethyl ether extracts of almond hulls (Nonpareil variety) using flash chromatography and preparative high-performance liquid chromatography. The triterpenoids, which comprised approximately 1% of the hulls, were characterized using chromatographic and spectroscopic methods. These studies demonstrate that almond hulls are a rich source of these triterpenoids, which have reported anti-inflammatory, anti-HIV, and anti-cancer activities.     

Changes in light attenuation during filling,stabilization and operation of a reservoir

Water, Air, &; Soil Pollution - Transformations in light attenuation (Kd) and Secchi disc transparency (SD) in Round Valley Reservoir, New Jersey, are documented over a 17 yr period...     

Re-evaluating Asia

Harland, Bryce Collision Course: America and East Asia in the Past and Future. da Cunha, Derek (ed.) The Evolving Pacific Power Structure. King, Peter and Kibata, Yoichi (eds) Peace Building in the Asia Pacific Region: Perspectives from Japan and Australia. Bell, Roger; McDonald, Tim and Tidwell, Alan (eds) Negotiating the Pacific Century: The ‘New’ Asia, the United States and Australia. Robison, Richard (ed.) Pathways to Asia: The Politics of Engagement.