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751.
ABSTRACT

Old cadastral maps represent a historical reference dataset for long-term land-use reconstructions. This study presents identification of inconsistencies in the nineteenth century Franziscean cadastre, one of the largest sets of old cadastral maps worldwide, by comparing three versions of the maps and written documents created in the same period. We identified all parcels and their land-use in the four sub-sources in six study areas. The overall share of inconsistencies among 5 771 identified parcels is 7.4%, with the biggest share of inconsistency in agroforestry and forestry classes. The most frequent inconsistencies are of ‘Not differentiable land use’ (n = 212) and ‘Different land-use’ categories across the sub-sources (n = 113). We conclude that the frequency of uncertainties in old cadastral maps may limit the validity of historical land-use reconstructions, affecting the eventual restoration and management efforts based on such data. We provide a summary for the use of Franziscean cadastre.  相似文献   
752.
/ The paper investigates how the Canadian nonferrous sector is tackling the challenge of sustainable development. Although there is no consensus as to what sustainable development means in practice for management in the sector, at least three dimensions must be taken into account: (1) metals are recyclable, the availability of this resource is not a concern for the foreseeable future; (2) the need to minimize environmental impacts of metals exploration, extraction, transformation, consumption, and recycling; and (3) production activities should not be socially or culturally disruptive. The nonferrous mining industry faces several environmental problems. Some of the most significant are acid mine drainage, sulfur emissions, recycling, and metals toxicity. The industry has developed a number of responses to address these specific concerns as well as other more general challenges. Six strategies are described and analyzed: (1) research and development, (2) an effort of consensus building among stakeholders known as the Whitehorse Mining Initiative, (3) international networking, (4) active involvement in the development of environmental management standards, (5) management reorganization and (6) voluntary agreements. The importance of external factors in the shaping of corporate environmental management practices is discussed, in particular the role of government. Progress has been achieved in three areas: (1) managerial practices and organization, (2) reducing the impacts of ongoing operations and (3) minimizing future liabilities, but two significant fields of conflict remain, namely mining in wilderness areas and projects on aboriginal lands.KEY WORDS: Canada; Environmental management; Minerals industry; Nonferrous metals; Sustainable development; Whitehorse Mining Initiative  相似文献   
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最近我们对美国东南部地区许多水域系统肉食性鱼类身上可能造成健康危险的超标汞(Hg)含量进行了测量.根据从出版的有关汞的水地球化学的实验数据得出的假设,我们调查了某些自然和人为的条件对莫尔比-亚拉巴马河系(MARS)中现场甲基汞(MeHg)含量的影响.从不同类型的环境采集了水样,假设这些水样具有不同的水甲基汞含量,并分析了总汞(THg)和甲基汞浓度以及一些主要的地球化学参数.结果如下:①总的来说,莫比尔-亚拉巴马河系水域中的总汞浓度分布相当均匀,从0.2ng/L到6ng/L不等,表明除了地质来源外,大气沉降肯定是所研究的水系中汞输入的主要来源.②在具有可比较的总汞含量的地点,以甲基汞形式存在的汞部分在从莫比尔-亚拉巴马河系的沿岸平原部分采集的样品中的含量始终比从其他地质区域采集的样品中的高.③我们的现场观测证实了从实验室试验获得的结论,即:甲基汞在水域系统中的丰度与硫酸盐(但只是在较窄的浓度范围内)有关,以及与pH的减少相关,而与硝酸盐或磷酸盐均无直接的关系.④对单一场所生物区中汞的累积的调查表明,在总汞浓度较低但甲基汞/总汞之比较高的水域系统中,生物的汞含量可能超出安全界限.因此,即使水相没有显示出有汞严重富集的迹象,也可能存在对食鱼人群的潜在健康威胁.  相似文献   
758.
Little is known about seasonal changes in burrowing activity and burrow architecture in subterranean African mole-rats (Bathyergidae, Rodentia). The solitary genus Heliophobius is the least known genus of this family. We examined burrow systems of the silvery mole-rat ( Heliophobius argenteocinereus) in Malawi in two periods of the dry season. Burrow pattern was influenced by the time of the year, becoming more reticulated at the peak of the dry season when soil was dry and hard. Overall digging activity did not cease during the dry season; yet burrowing strategy changed and the soil was deposited in tunnels rather than transported to mounds. The length of burrow systems was correlated with the body mass of the respective occupants. In spite of their solitary habits – and contrary to the prediction of the aridity food-distribution hypothesis – silvery mole-rats are able to occupy poor habitats with low food supply.  相似文献   
759.
Brás I  Lemos L  Alves A  Pereira MF 《Chemosphere》2005,60(8):1095-1102
The minimization of pentachlorophenol (PCP) transport in the environment driven by industrial wastewater discharges can be accomplished by sorption in natural, available and low cost by-products like pine bark. Taking into account that PCP is a chemical which behaviour is highly dominated by the surrounding features, this work intended to evaluate the sorption kinetics and equilibrium parameters according to the pH and temperature as well as the pine bark particle size. The PCP uptake by pine bark showed to be faster in the initial phase followed by a slower process, being 24 h the suitably time to reach the sorption equilibrium in the range of pH studied. The neutral PCP species showed to have higher binding capacity to pine bark than the anionic PCP, which was reflected in a decrease in the distribution coefficient (Kd) of the linear sorption isotherm with the increase of solution pH from 2 to 7. On the other hand, between 10 degrees C and 35 degrees C, the temperature does not seem to play a significant role in the PCP sorption by pine bark, while the sorbent size is a key parameter to enhance the overall process.  相似文献   
760.
Large amounts of 137Cs have been accidentally released to the subsurface from the Hanford nuclear site in the state of Washington, USA. The cesium-containing liquids varied in ionic strengths, and often had high electrolyte contents, mainly in the form of NaNO3 and NaOH, reaching concentrations up to several moles per liter. In this study, we investigated the effect of ionic strengths on Cs migration through two types of porous media: silica sand and Hanford sediments. Cesium sorption and transport was studied in 1, 10, 100, and 1000 mM NaCl electrolyte solutions at pH 10. Sorption isotherms were constructed from batch equilibrium experiments and the batch-derived sorption parameters were compared with column breakthrough curves. Column transport experiments were analyzed with a two-site equilibrium-nonequilibrium model. Cesium sorption to the silica sand in batch experiments showed a linear sorption isotherm for all ionic strengths, which matched well with the results from the column experiments at 100 and 1000 mM ionic strength; however, the column experiments at 1 and 10 mM ionic strength indicated a nonlinear sorption behavior of Cs to the silica sand. Transport through silica sand occurred under one-site sorption and equilibrium conditions. Cesium sorption to Hanford sediments in both batch and column experiments was best described with a nonlinear Freundlich isotherm. The column experiments indicated that Cs transport in Hanford sediments occurred under two-site equilibrium and nonequilibrium sorption. The effect of ionic strength on Cs transport was much more pronounced in Hanford sediments than in silica sands. Effective retardation factors of Cs during transport through Hanford sediments were reduced by a factor of 10 when the ionic strength increased from 100 to 1000 mM; for silica sand, the effective retardation was reduced by a factor of 10 when ionic strength increased from 1 to 1000 mM. A two order of magnitude change in ionic strength was needed in the silica sand to observe the same change in Cs retardation as in Hanford sediments.  相似文献   
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