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21.
The industrialization of agriculture not only alters the ways in which agricultural production occurs, but it also impacts the decisions farmers make in important ways. First, constraints created by the economic environment of farming limit what options a farmer has available to him. Second, because of the industrialization of agriculture and the resulting economic pressures it creates for farmers, the fact that decisions are constrained creates new ethical challenges for farmers. Having fewer options when faced with severe economic pressures is a very different situation for farmers than having many options available. We discuss the implications of constrained choice and show that it increases the likelihood that farmers will consider unethical behavior.  相似文献   
22.
The restoration of river environments has been of growing importance to river management and planning in the UK. The extension of ecological restoration to floodplains as well as river channels is more complex, partly because of the range of stakeholders and the diversity of relevant management institutions. This paper draws on a qualitative survey of river managers in the UK to identify institutional factors relevant to the success or failure of floodplain restoration projects.  相似文献   
23.
Throughout history, mining communities have invariably found themselves striving for a good quality of life and a long‐term future. In the 21st century, problems of maintaining the economic vitality of mining regions are now compounded by concerns about the biophysical integrity of the local environment. In regions of the world where the economic viability of the resource is marginal and achieving a reasonable quality of life is a daily struggle, sustainable mining may seem to be a dubious prospect at best. Yet the twin imperatives of global political forces and burgeoning environmental concerns are requiring industry, governments and other interests to re‐conceptualize the way in which mining takes place in communities. Although mining itself may not be seen as an industry that contributes to the achievement of environmental objectives, it could — with careful planning — be used as a tool to foster a more sustainable and healthier community. This argument is considered in the context of the coal mining region of Santa Catarina, Brazil.  相似文献   
24.
The development, testing, and application of a probabilistic model framework for the light attenuation coefficient for downwelling irradiance (Kd) and Secchi disc transparency (SD) that resolves the effects of several light attenuating constituents, including phytoplankton and nonliving particles (tripton), is documented. The model is consistent with optical theory, partitioning the magnitudes of the light attenuating processes of absorption and scattering according to the contributions of attenuating constituents as simple summations. The probabilistic framework accommodates variations in the character and concentrations of these constituents and ambient conditions during measurements, and recognizes a linear relationship between the magnitudes of absorption and scattering by tripton. The model is tested and applied for a 21 km reach of the Seneca River, New York, that features optical gradients caused by an intervening hypereutrophic lake and dam, and a severe infestation of the exotic zebra mussel. The model is applied to resolve the roles of phytoplankton and tripton in regulating measured longitudinal patterns of SD along the study reach of the river and increases in SD since the zebra mussel invasion, and to predict decreases in Kd since the invasion.  相似文献   
25.
Increasing value is attributed to mangroves due to their considerable capacity to sequester carbon, known as ‘blue carbon’. Assessments of opportunities and challenges associated with estimating the significance of carbon sequestered by mangroves need to consider a range of disciplinary perspectives, including the bio-physical science mangroves, social and economic issues of land use, local and international law, and the role of public and private finance. We undertook an interdisciplinary review based on available literature and fieldwork focused on parts of the Mekong River Delta (MRD). Preliminary estimates indicate mangrove biomass may be 70–150 t ha?1, but considerably larger storage of carbon occurs in sediments beneath mangroves. These natural stores of carbon are compromised when mangroves are removed to accommodate anthropogenic activities. Mangroves are an important resource in the MRD that supplies multiple goods and services, and conservation or re-establishment of mangroves provides many benefits. International law and within-country environmental frameworks offer increasing scope to recognize the role that mangrove forests play through carbon sequestration, in order that these might lead to funding opportunities, both in public and private sectors. Such schemes need to have positive rather than negative impacts on the livelihoods of the many people living within and adjacent to these wetlands. Nevertheless, many challenges remain and it will require further targeted and coordinated scientific research, development of economic and social incentives to protect and restore mangroves, supportive law and policy mechanisms at global and national levels, and establishment of long-term financing for such endeavours.  相似文献   
26.
An assessment of the heavy metal content and biological pollution burden of an abattoir dumpsite, an automobile carwash, the Ikpoba River, and a private water borehole located near the abattoir dumpsite was conducted in Benin City in Southern Nigeria, during the rainy and dry seasons. The water samples’ pH was lower than the permissible values, with the river water displaying color and possessing a slight odor. Iron concentrations exceeded the permissible limits for drinking water at all four of the sampling stations in the study area, although not in samples collected from the control station, station 5, a public water borehole that is located some distance away. Lead values were higher than drinking water standards in the samples collected from stations 1 through 4, with some exceptions during the rainy season. Copper, nickel, arsenic, chromium, and aluminum were detected in three out of the four sampling stations located within the study area. However, these metals were detected at levels that were within regulatory limits. The detection of three metals (iron, lead, and zinc) within the study area at levels exceeding drinking water limits suggested that a complete cycle of movement of pollutants into the sampling stations had occurred. Significant biological presences were also detected, as the Ikpoba River water had a standard plate count (SPC) of 130 most probable number (MPN) and a 22 MPN presumptive coliform count (PCC) or 22 MPN. However, Escherichia coli (E. coli) confirmatory tests recorded less than 2 MPN in both seasons. The study has shown that the quality of water in the river may be compromised by effluent discharges from the dumpsite and the carwash channel. Therefore, this situation requires more stringent enforcement of local environmental laws and maintenance of safe distances between domestic and industrial waste sources and domestic or private water wells.  相似文献   
27.
Pollution has taken on a global dimension, and the effects are most obvious in developing countries. The effects take a toll on human health, animals, and vegetation, as well as on soil, air, and water quality. The objective of this article is to discuss the current relationships among pollution, environmental quality, and human health within the frame of anthropogenic activities in developing countries. In addition to personal observations, we review relevant literature on conditions throughout the developing world and case studies on conditions and activities in Nigeria. Key findings show the significant, adverse contributions to human health and environmental risk from current waste generation and handling practices, indoor and outdoor air pollution, wastewater and effluent generation and disposal, the hazardous nature and pollution potential of wastes, and the human behaviors that contribute to pollution in developing countries. There is an urgent need to create awareness among the various segments of society of the human health hazards posed by pollution as well as a need for the comprehensive development and enforcement of appropriate policies to prevent a descent into an abyss of deteriorating human and environmental health.  相似文献   
28.
The consumption, disposal, material and chemical compositions of rechargeable electric torch wastes (RETWs) were investigated in Ibadan, Nigeria. Twenty-five RETWs of ten models were collected and disassembled. Their battery electrodes (BEs) and printed circuit boards (PCBs) were acid digested and leached using United States Environmental Protection Agency (USEPA) method 3050B and USEPA Method 1311, respectively. The digests and extracts were analysed for total and extractable Pb, Cd, Cr and Ni using atomic absorption spectrophotometer. The US Test method (CPSC-CH-E 1002-08) was used for digestion of the plastic components. Two hundred questionnaires were distributed to users in Ibadan to determine their usage of RETs and their management when spent. The results indicated that BEs contributed the highest percentage (44 %) component, followed by plastic (38 %). Other components include metal, PCBs, glass and wire. Of the respondents, 61.9 % dispose their spent torches in dumpsites. The mean ± SD concentrations of Pb, Cd, Cr and Ni in the BEs were 500 ± 109 g/kg, 3.94 ± 6.84 mg/kg, 0.33 ± 0.88 mg/kg, 1.68 ± 0.74 mg/kg respectively; in the PCBs, they were 684 ± 42 g/kg, 13.7 ± 17.8 mg/kg, 13.5 ± 10.2 mg/kg and 193 ± 437 mg/kg; and in the plastics, they were 14.1 g/kg, 5.33 mg/kg, 17 mg/kg, and 4.67 mg/kg respectively. The extractable Pb in BE (2670 mg/L) and PCBs (235 mg/L) exceeded the Toxicity Characteristics Leaching Procedure (TCLP) limit of 5 mg/L. RETWs present potential environmental problems in the absence of effective recycling.  相似文献   
29.
Sensors and enabling technologies are becoming increasingly important tools for water quality monitoring and associated water resource management decisions. In particular, nutrient sensors are of interest because of the well‐known adverse effects of nutrient enrichment on coastal hypoxia, harmful algal blooms, and impacts to human health. Accurate and timely information on nutrient concentrations and loads is integral to strategies designed to minimize risk to humans and manage the underlying drivers of water quality impairment. Using nitrate sensors as the primary example, we highlight the types of applications in freshwater and coastal environments that are likely to benefit from continuous, real‐time nutrient data. The concurrent emergence of new tools to integrate, manage, and share large datasets is critical to the successful use of nutrient sensors and has made it possible for the field of continuous monitoring to rapidly move forward. We highlight several near‐term opportunities for federal agencies, as well as the broader scientific and management community, that will help accelerate sensor development, build and leverage sites within a national network, and develop open data standards and data management protocols that are key to realizing the benefits of a large‐scale, integrated monitoring network. Investing in these opportunities will provide new information to guide management and policies designed to protect and restore our nation's water resources.  相似文献   
30.
This study analyzed insolation data to account for multiple scattering in calculating optimal tilt angles for stationary and seasonally moving photovoltaics on three different roof types in the US Pacific Northwest: vegetated roofs, white roofs, and dark roofs. Using these results, we modeled the energy savings for vegetated roofs and roofs covered in varying numbers of photovoltaic panels. We then calculated the net present value, internal rate of return, and other economic measures for all possible combinations of covering rooftops in mixes of photovoltaic arrays and vegetation, accounting for installation costs, proposed carbon taxes, stormwater management discounts, and other relevant factors. Our results quantify how, in the US Pacific Northwest and similar locations, photovoltaics produce higher returns on investment than do vegetated roofs for new buildings, while vegetated roofs produce better returns on investment than do photovoltaics for older buildings. This is important because in many areas, some buildings have photovoltaics when a vegetated roof would have been more cost and energy efficient, while other buildings have vegetated roofs when photovoltaics would have been more cost and energy efficient. Potential applications include modifying incentive programs and other policies to account properly for building age, use, and other relevant factors to ensure building owners make the most energy-efficient decisions between photovoltaic versus vegetated roof installation. Our research also demonstrates how positive returns on investment can be realized in the US Pacific Northwest and similar regions through vegetated roofs and photovoltaics provided they are each installed optimally.  相似文献   
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