Land Use,Geology, Enrichment,and Stream Biota in the Eastern Ridge and Valley Ecoregion: Implications for Nutrient Criteria Development1

Abstract: The eastern panhandle region of West Virginia is entirely within the Appalachian Ridge and Valley ecoregion. It is underlain by limestone in the eastern part and by shale and sandstone in the western part. Agricultural and urban development has affected the condition of the streams of this region. We examined samples from 165 stations in the Ridge and Valley, collected from 1998 to 2004. Land use, geological characteristics, physical and chemical parameters, and algal and macroinvertebrate assemblages were used to identify potential stressors that affect streams in the region. Our analyses indicated that both human land uses and ecoregional differences led to elevated nutrient concentrations in streams of the study areas. Multiple regression analyses indicated that both agricultural and urban land use in the watershed were associated with high nutrient concentrations (NO₂₊₃, total nitrogen, and total phosphorus) in streams. These elevated nutrient concentrations have led to increased algal biomass, increased trophic state, and degradation of macroinvertebrate community in the streams. Values of the West Virginia Stream Condition Index, as well as several other benthic macroinvertebrate metrics, decreased with increased nutrient concentrations and conductivity, especially in the limestone region. When regional differences were partitioned out in the analysis, nutrient concentrations became the strongest stressor in the limestone region while conductivity exhibited less of an effect on macroinvertebrate metrics. Meanwhile, periphyton diagnostic metrics also responded to increased nutrient concentrations, suggesting nutrients could be a cause of biological degradation in the Eastern Ridge and Valley region. Multiple approaches and multiple lines of evidence (reference approach and stressor‐response approach) were applied to develop nutrient benchmarks for different geological regions in the study watershed.     

Analytical solution for Joule–Thomson cooling during CO2 geo-sequestration in depleted oil and gas reservoirs

Mathematical tools are needed to screen out sites where Joule–Thomson cooling is a prohibitive factor for CO₂ geo-sequestration and to design approaches to mitigate the effect. In this paper, a simple analytical solution is developed by invoking steady-state flow and constant thermophysical properties. The analytical solution allows fast evaluation of spatiotemporal temperature fields, resulting from constant-rate CO₂ injection. The applicability of the analytical solution is demonstrated by comparison with non-isothermal simulation results from the reservoir simulator TOUGH2. Analysis confirms that for an injection rate of 3 kg s^?1 (0.1 MT yr^?1) into moderately warm (>40 °C) and permeable formations (>10^?14 m² (10 mD)), JTC is unlikely to be a problem for initial reservoir pressures as low as 2 MPa (290 psi).     

Natural and waste materials as metal sorbents in permeable reactive barriers (PRBs)

A range of waste products and natural materials including chitin, fly ash, clay soil, cocoa shell, calcified seaweed and the natural zeolite clinoptilolite were tested in batch experiments to assess their ability to remove metals from a synthetic groundwater containing 10 mg l^–1 Cu, Pb and Zn and 1 mg l^–1 Cd. All had the ability to remove more than 70% of the metals from solution with fly ash being the most efficient, then chitin, clinoptilolite, calcified seaweed, clay soil and cocoa shell. After consideration of geochemical and morphological properties, calcified seaweed and clinoptilolite were shown to have potential as barrier materials. Given current issues with regard to the longevity of zero-valent iron barriers alternative materials could be the key to the future adoption of this remediation technology.     

NORMALIZED AGRICULTURAL PRICES AND WATER RESOURCES PLANNING1

ABSTRACT: Short-term fluctuations in agricultural markets necesitate adjustments in market prices for use in water resources planning. Two procudures for this price normalizing are described and evaluated. The linear treand and weighted average normalizing procedures perform reasonably well, except in cases of dramatic price oscillations.     

Migrant land rights reception and 'clearing to claim' in sub-Saharan Africa: A deforestation example from southern Zambia

The relationship between migration and deforestation in the developing world continues to receive significant attention. However beyond direct population increase, the precise mechanisms that operate within the intersection of migrant/host land rights remain largely unexamined. Where migrants are provided with land and rights by the State and/or local communities, how such rights are perceived by the migrants is of primary importance in their interaction with land resources, and in aggregate it impacts the development opportunities and environmental repercussions of migration. The authors analyze the operative aspects of land rights reception (as opposed to provision) by migrant populations, and the relationship between this reception and deforestation. The article examines a case in Zambia to analyze how tenurial constructs, emerging from the way rights are perceived by migrants, lead to the continued clearing of areas much larger than needed for cultivation, even when the arrangement appears counter‐productive in terms of land rights provision and labour allocation. While valuable policy efforts have focused on providing resource rights to migrants, how such rights are received and the relationship of this reception to resource management needs greater policy attention.     

Polychlorinated dibenzofurans/dibenzo-p-dioxins (PCDF/PCDDs) and other dioxin-like substances in marine organisms from the Grenland fjords,S. Norway, 1975-2001: present contamination levels,trends and species specific accumulation of PCDF/PCDD congeners

Discharge of WHO toxicity equivalents (TEQs) of PCDF/PCDDs to Frierfjorden, Norway has been reduced from an estimated sum of 50-100 kg in the period 1951-1975 to about 6-7 kg in 1976-1990, and further to about 20 g for 1991-2000. In accordance with this, the yearly monitoring since 1987 has shown considerably decreasing contamination in organisms, first highly significant in all indicator species from 1990 to 1991, then levelling off. Present concentrations thus are still high. Compared with estimated "high background" (reference) concentrations of 10 ng TEQ(PCDF/PCDD)/kg w.w. in liver of cod and in hepatopancreas ("brown meat") of crabs, Frierfjord samples in 2001 were about 60 and 70 times higher, respectively. With considerable uncertainty due to large fluctuations, the rate of yearly decrease for TEQ(PCDF/PCDD) in cod liver 1991-2001 has been calculated to 10-12%. A hypothetic target value of 50 ng TEQ/kg w.w. will not be reached until 2015-2020, possibly even later. Including contributions from dioxin-like PCBs and PCNs, the weekly maximum tolerable amount of cod liver and crab hepatopancreas from Frierfjorden in 2001 were about 2-3 g. Multivariate analysis of PCDF/PCDD congener profiles in four fish species, mussels and crabs resulted in five distinct groups, separating four of the species and grouping the remaining two together, hence demonstrating examples of species specific accumulation characteristics.     

瑞典山区的驯鹿:放牧影响的评价

过去十年中,几例放牧引起植被退化的事件曝光已经使瑞典官方认为一些山区有过度放牧现象以及驯鹿养殖在生态学上可能并非是可持续的.我们从时间和管理角度对这些例子进行研究,进而评价放牧对瑞典山区夏季草场的影响程度.有关驯鹿种群长期动态的数据表明,上个世纪驯鹿的数量在225000头左右波动,没有变化的趋势.根据达拉纳(Dalarna)的郎格夫贾莱特(Langfjallet)和海里耶达(Harjedalen)的米塔克勒盆(Mitaklappen)的数据,对放牧影响进行了详细的讨论.我们将这些数据与近几十年养殖在生态学上似乎不可持续的挪威芬马克地区以及芬兰北部的情况进行了比较,我们的结论是大规模的驯鹿过度放牧在瑞典山区不明显.但在封闭和围栏养殖时,可见过度放牧和践踏的影响.