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361.
While analyzing overall planning and coordinated development of urban-rural areas, this paper shows that overall planning for the development of urban-rural areas is a requirement for the best use of productive forces. It means the setting up of a policy mechanism for coordinated growth. Recognizing this, the government should set up a way to lead and manage a unified program to increase service and decrease controlling administration power, while safeguarding and fulfilling the farmers' ownership to the means of production. 相似文献
362.
5A级景区最大承载量很大程度上反映出区域旅游资源的供给能力。通过对不同省市、不同类型旅游景区最大承载量的数理统计与空间展布,分析我国5A级景区最大承载量的省域空间差异和类型空间差异规律。结果表明:我国5A级旅游景区最大承载量空间分布不均衡,空间差异特征与人口分布规律较为一致;区域差异与类型差异可供景区规划布局和旅游者决策参考。 相似文献
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本文针对北京城市建设面临的自然与人为灾害背景,简要论述了北京地震、水灾、火灾及“新致灾源”的历史及现状,强调开展首都圈灾害研究及减灾规划设计的重要性,并提出了系统的减灾方略及相应的管理构想。 相似文献
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366.
Methylmercury, total mercury and total selenium in four common freshwater fish species from Ya-Er Lake, China 总被引:1,自引:0,他引:1
Snakehead fish (Ophiocephalus argus cantor), silver carp (Hypophthalmichthys molitrtix), crucian carp (Carassius carassius), and common carp (Cyprinus carpio) are four common freshwater fish species in China. In this study, the level of methylmercury (MeHg), total mercury (T-Hg), and total selenium (T-Se) in muscle samples of these four fish species from Ya-Er Lake, China, were analyzed using atomic fluorescence spectrometry coupled with high-performance liquid chromatography, and inductively coupled plasma mass spectrometry. The concentrations of MeHg in all the fish species were significantly correlated with those of T-Hg. Higher T-Hg and MeHg concentrations had accumulated in the snakehead fish, which is a strongly predatory fish, than in the other three species. The concentration ratios of MeHg and T-Hg in the muscles of these four fish species were almost equal. Conversely, there was negative correlation between the concentrations of T-Hg and T-Se, which implies that there is a competition between these two elements with respect to bioaccumulation. It is noteworthy that of all the muscle samples tested, the level of T-Hg exceeded the maximum allowable limit in fish [0.4 mg kg−1 (w/w) recommended by the World Health Organization] in 38.46% of those of the silver carp, 18.18% of those of the crucian carp, and 100% of those of snakehead fish. These results show that the consumption of contaminated fish is a potential threat to human health and that necessary preventive measures to safeguard public health should be emphasized. 相似文献
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368.
The metallurgy industry and municipal waste incinerators are considered the main sources of polychlorinated dibenzo-p-dioxin and dibenzofurans (PCDD/Fs) in many countries. This study investigated the emission factors and total emissions of PCDD/Fs and dioxin-like polychlorinated biphenyls (PCBs) emitted from metallurgy industries (including ferrous and nonferrous foundries) in Korea. The toxic equivalency (TEQ) emission factor of PCDD/Fs was the highest for secondary copper production, at 24451 ng I-TEQ/ton. The total estimated emissions of PCDD/Fs from these sources were 35.259 g I-TEQ/yr, comprising 0.088 g I-TEQ/yr from ferrous foundries, 31.713 g I-TEQ/yr from copper production, 1.716 g I-TEQ/yr from lead production, 0.111 g I-TEQ/yr from zinc production, and 1.631 g I-TEQ/yr from aluminum production. The total estimated annual amounts of dioxin-like PCBs emitted from these sources were 13.260 g WHO-TEQ/yr, comprising 0.014 g WHO-TEQ/yr from ferrous foundries, 12.675 g WHO-TEQ/yr from copper production, 0.170 g WHO-TEQ/yr from lead production, 0.017 g WHO-TEQ/yr from zinc production, and 0.384 g WHO-TEQ/yr from aluminum production. The highest emission factor was found for secondary copper smelting, at 9770 ng WHO-TEQ/ton. 相似文献
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370.