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201.
Rodolfo Sousa Marcello Veiga Dirk Van Zyl Kevin Telmer Sam Spiegel Jeff Selder 《Journal of Cleaner Production》2011,19(6-7):742-750
In Brazil, artisanal and small-scale gold mining (ASGM) produces in the range of 6 tonnes of gold (Au) per annum, and employs approximately 200,000 people. Most of this mining activity is in the Amazon region, where miners have been extracting gold for more than 40 years. In the Tapajos River Basin, assessments indicate that around 99% of miners operate without the environmental and mining permits required by law. This is a result of a combination of unrealistic or lack of proper policies and regulations, lack of political will, lack of infra-structure to enforce the existing regulations and lack of incentives to miners to comply with legal requirements.In this article, we analyze a group of 20 laws, decrees and resolutions in Brazil, focusing on how idiosyncrasies in these regulations reveal gaps between policy and reality in ASGM areas. Artisanal miners operate in vast and remote areas and the government lacks the resources (personnel, vehicles, information and materials) to enforce the laws. Our analysis emphasizes the need for creating new government commitments and identifying priority areas where government agents can focus their efforts.There is no single solution for the environmental, health, technical and socio-economic problems associated with ASGM. However, a realistic approach should consider improving the level of education of miners, creating government programs to provide technical assistance in the field, simplifying administrative procedures and ensuring adequate measures for enforcement. 相似文献
202.
Volk C Wood L Johnson B Robinson J Zhu HW Kaplan L 《Journal of environmental monitoring : JEM》2002,4(1):43-47
The presence of natural organic matter (NOM) strongly impacts drinking water treatment, water quality, and water behavior during distribution. Dissolved organic carbon (DOC) concentrations were determined daily over a 22 month period in river water before and after conventional drinking water treatment using an on-line total organic carbon (TOC) analyzer. Quantitative and qualitative variations in organic matter were related to precipitation and runoff, seasons and operating conditions. Following a rainfall event, DOC levels could increase by 3.5 fold over baseflow concentrations, while color, UV absorbance values and turbidity increased by a factor of 8, 12 and 300, respectively. Treated water DOC levels were closely related to the source water quality, with an average organic matter removal of 42% after treatment. 相似文献
203.
Mark H. Houck Jeff R. Wright James T. Diamond Graham Toft 《Journal of the American Water Resources Association》1988,24(3):651-659
ABSTRACT: Indiana has embarked on a program to assess the condition of its infrastructure and to plan for its future. The perspective of this planning differs from the traditional “master plan” approach — instead, the focus is on competitiveness for economic development. The initial work on the water and sewerage competitiveness of the infrastructure includes: (1) a comparative analysis of the water resources and infrastructure of Indiana and its industrial midwestern neighbors; (2) a technology scan to identify possible technological opportunities that may be important for Indiana; and (3) a set of recommendations for future planning. This work is preliminary in nature but should serve as a starting point for continued strategic planning over the next decade for positioning of Indiana's water and sewerage infrastructure as a key element in the economic growth equation. 相似文献
204.
Using a turtle-borne camera system, changing flipper beat frequency and amplitude were measured in five diving green turtles
(Chelonia mydas Linnaeus 1758) in the Bahía de los Angeles, Mexico (28°58′N, 113°33′W). These observations were made between June and August
2002. Turtles worked hardest (i.e., had the highest flipper beat frequency and amplitude) at the start of descents when positive
buoyancy is predicted to oppose their forward motion. During the later part of descents, turtles worked less hard in line
with opposing buoyancy forces being reduced. For example, flipper beat frequency declined from about 60–80 beats min−1 at the start of descent to around 25–40 beats min−1 after 30 s of the descent. At the start of ascents the flipper beat frequency was around 30 beats min−1, lower than on descent, and declined as the ascent progressed with often passive gliding for the final few meters to the
surface. This pattern of effort during diving appears to apply across a range of marine reptiles, birds and mammals suggesting
that graded effort during descent and ascent is an optimum solution to minimising the cost of transport during diving. 相似文献
205.
Wind Characteristics of Mesquite Streets in the Northern Chihuahuan Desert, New Mexico, USA 总被引:2,自引:0,他引:2
Past research has shown that the most important areas for active sand movement in the northern part of the Chihuahuan Desert
are mesquite-dominated desert ecosystems possessing sandy soil texture. The most active sand movement in the mesquite-dominated
ecosystems has been shown to take place on elongated bare soil patches referred to as “streets”. Aerodynamic properties of
mesquite streets eroded by wind should be included in explaining how mesquite streets are more emissive sand sources than
surrounding desert land. To understand the effects of wind properties, we measured them at two flat mesquite sites having
highly similar soil textures but very different configurations of mesquite. The differences in wind properties at the two
sites were caused by differences of size, orientation, and porosity of the mesquite, along with the presence of mesquite coppice
dunes (sand dunes stabilized by mesquites growing in the dune and on its surface) found only at one of the two sites. Wind
direction, u* (friction velocity), z0 (aerodynamic roughness height) and D (zero plane displacement height) were estimated for 15-m tower and 3-m mast data. These aerodynamic data allowed us to distinguish
five categories with differing potentials for sediment transport. Sediment transport for the five categories varied from unrestricted,
free transport to virtually no transport caused by vegetation protection from wind forces. In addition, “steering” of winds
below the level of the tops of mesquite bushes and coppice dunes allowed longer parallel wind durations and increased wind
erosion for streets that aligned roughly SW–NE.
U.S. Government right to retain a non-exclusive royalty-free licence in and to any copyright is acknowledged. 相似文献
206.
Jeff Cooper 《Local Environment》2013,18(3):325-330
207.
208.
Privately owned parks continue to attract interest across the tropics for their ability to blend biodiversity protection with sustainable development. Despite rapid proliferation of these privately owned protected areas, the conservation community knows little about them. We interviewed owners of 68 private parks in Costa Rica to learn more about their contribution to that country's national conservation effort. Key findings include: (1) the total number of private reserves is estimated to be in the vicinity of 250; (2) reserves fell into a wide variety of categories, ranging from formal parks and ecotourism reserves to biological stations and hybrid reserves; (3) total nationwide coverage is approximately 63,832 ha, or 1.2% of the national territory; (4) reserves were protecting ecologically important habitat, particularly primary rain forest; (5) reserves were owned mostly by Costa Ricans; (6) reserves were used for a wide variety of activities, especially ecotourism and for the owners' personal enjoyment; (7) reserve owners' biggest problem was poaching of mammals; (8) reserves were protecting key corridor and buffer zone areas between and around larger national parks. Results from this study should help enhance our understanding of this little-known conservation and development tool. They should be of interest wherever biodiversity remains threatened and wherever new conservation and development partners are being sought - which includes most of the developing world. 相似文献
209.
210.
James Nelson Rachel Wilson Felicia Coleman Christopher Koenig Doug DeVries Chris Gardner Jeff Chanton 《Marine Biology》2012,159(2):365-372
Seagrass meadows are among the most productive ecosystems in the marine environment. It has been speculated that much of this
production is exported to adjacent ecosystems via the movements of organisms. Our study utilized stable isotopes to track
seagrass-derived production into offshore food webs in the northeastern Gulf of Mexico. We found that gag grouper (Myctereoperca microlepis) on reefs as far as 90 km from the seagrass beds incorporate a significant portion of seagrass-derived biomass. The muscle
tissue of gag grouper, a major fisheries species, was composed on average of 18.5–25% seagrass habitat-derived biomass. The
timing of this annual seagrass subsidy appears to be important in fueling gag grouper egg production. The δ34S values of gag grouper gonad tissues varied seasonally and were δ34S depleted during the spawning season indicating that gag utilize the seagrass-derived biomass to support reproduction. If
such large scale trophic subsidies are typical of temperate seagrass systems, then loss of seagrass production or habitat
would result in a direct loss of offshore fisheries productivity. 相似文献