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511.
Nowadays, more people tend to spend their recreational time in large national parks, and trace metal(loid)s in soils have attracted long-term attention due to their possible harm to human health. To investigate the pollution levels, potential sources and health risks of trace metal(loid)s in road soils, a total of eight trace metal(loid)s (including As, Cd, Cr, Cu, Ni, Pb, Zn and Hg) from 47 soil samples along roads were studied in the Huangshan National Park in Southeast China. The results showed that the concentrations of As, Cd, Pb, Zn and Hg appeared different degrees of pollution compared with their corresponding background values. According to the pollution indices, Hg and Cd were recognized as significant pollutants presenting moderate to high ecological risk. Combining principal component analysis and positive matrix factorization model, the results showed that traffic, industrial, agricultural and natural sources were the potential origins of trace metal(loid)s in this area, with contribution rates of 39.93%, 25.92%, 10.53% and 23.62%, respectively. Non-carcinogenic risks were all negligible, while the carcinogenic risk of As was higher than the limit (1 × 10−6). Moreover, children were more susceptible to trace metal(loid)s by ingestion which appeared to be a more important exposure pathway than dermal contact and inhalation. The contribution rates of different sources to non-carcinogenic risks and carcinogenic risks were similar among children and adults, while traffic and industrial sources have a significant impact on health risks. This study will give more insights to control the environmental risks of trace metal(loid)s in national parks.  相似文献   
512.
As green infrastructure gets its attention in hazard mitigation, it is necessary to improve general understanding on what makes green infrastructure important for hazard and resiliency research. To better understand how green infrastructure fits with more traditional notions of structural and nonstructural mitigation, this study examines the relationship between green infrastructure and ‘structural and nonstructural’ mitigation approaches for hazard mitigation. Also, this study discusses a new measurement of locational aspects and spatial patterns of green infrastructure by utilizing high-resolution data in urban areas, and its potential implementation in hazard mitigation. Compared to previous research using land-use land-cover datasets, the normalized difference vegetation index (NDVI) utilizing National Agriculture Imagery Program dataset provides an ability to capture green infrastructure in greater detail. A visual comparison suggests that the NDVI data are able to capture and identify more types of ‘green’ land uses in Harris County. The total green infrastructure percentages for Harris County, Texas, based on 1-m high resolution were found to be 61.5% of the area, compared to the 51.5% based on the National Land Cover Database. This study provides support for utilizing high-resolution data to establish guidelines for green infrastructure’s spatial characteristics and sustainable hazard mitigation. The outcomes of this study will be helpful in the strategic planning and implementation of green infrastructure in urban areas with hazard issues.  相似文献   
513.
为有效降低室内PM2.5,指导间接蒸发冷却新风机组的设计选型,推导了新风机组净化效力和净化能效评价指标的数学表达式,并利用自行研制的间接蒸发冷却新风机组,分析了2种过滤器在不同运行工况下净化PM2.5的特性。结果表明,MERV 7+16和MERV 7+13的计数效率均随颗粒物粒径增加而提高,且前者的计数效率高于后者;由于滤材的不同,MERV 7+16的初阻力更小。MERV 7+16的渗透系数更小,其净化效力也要大于MERV 7+13;由于PM10在室内的自然沉降作用更显著,过滤器对PM10的净化效力明显大于PM2.5和PM1。将室内新风负荷作为新风机组能耗的一部分,在对比天津和南宁地区新风机组的净化能效时发现,由于两地区冬季室外温度存在明显差异,导致处于天津地区的新风机组若要在冬季获得同等的洁净空气量,需付出更多的能耗代价。  相似文献   
514.
为了对风险形式多样化的电网进行全面客观的评估,提出了一种基于博弈赋权和灰色关联投影的电网综合风险评估方法。首先,通过分析现代电网面临的风险因素,从网架结构、运行状态、能源供给3个方面重新构建了风险评估指标体系;其次,基于博弈赋权模型融合指标主观权值与客观权值,最大化消除了单一赋权法造成的权值偏差;然后,通过灰色关联投影模型计算风险指标样本在理想解上的投影,并以风险指标样本对负理想解的优属度来表征电网综合风险大小;最后,通过案例分析验证了所提方法的有效性和正确性。研究所得电网综合风险评估结果具有合理性和可靠性,对电网调度规划决策的形成具有一定的指导作用。  相似文献   
515.
福建丰产荔枝园土壤微量元素含量的研究   总被引:2,自引:0,他引:2  
与我国红壤平均水平相比,福建丰产荔枝园土壤有效态锌、钼及水溶态硼含量较高,而活性锰及有效铜含量较低;土壤全锌、锰、钢量亦较低。在土壤pH4.54—8.76时,pH值与有效态钼含量呈较显著正相关,而与代换态锰、水溶态硼、有效态铁含量呈显著或极显著负相关。本文初步提出福建荔枝园土壤微量元素含量的适宜指标,可供土壤营养诊断及平衡施肥之参考。  相似文献   
516.
建立了包括生态资源、人类驱动和系统响应3方面17个指标在内的农业生态环境定量评价指标体系,结合广西柳城县的实际情况,运用模糊综合评价模型,对当地农业生态环境进行定量评价。结果表明,柳城县农业生态环境质量属于一般水平,当地自然生态条件较好,虽受人类活动影响较大,但生态系统运行依然正常。该评价结果与当地实际情况相符,表明该评价指标体系具有较强的科学性和实用性。依据评价结果,提出了改善柳城县农业生态环境的对策和建议。  相似文献   
517.
山西芦芽山旅游影响因子及其系数与地理因子间的关系   总被引:11,自引:0,他引:11  
旅游影响因子及其系数是评价旅游开发对生态环境影响程度的一种主要指标。本文采用样方调查的方法,对芦芽山旅游影响因子及其系数与地理因子进行了相关分析,结果表明:6个旅游影响因子之间的正负相关性均很好地体现了旅游活动对各因子影响的规律性,同时也说明了旅游影响因子的选择与确定以及对其赋值的正确性,旅游影响因子及其系数与自然地理因子间较小的正负相关性,说明它们几乎不受自然地理因子的作用,它们共同作用为评价旅游开发程度强弱的指标,具有一定的可行性,旅游影响因子及其系数与人文地理因子间的高相关性,完全可以说明,它们能够正确地反映旅游活动对植被环境的作用。此外,加强景区管理和旅游规划尤为迫切,图2表4参8。  相似文献   
518.
This study evaluated the potential toxicological risk posed to human health due to the exposure to heavy metals by water ingestion in an area affected by tanneries – the Cadeia-Feitoria hydrographic basin (Brazil). River water was collected at 10 sites, every 3 months, from July 1999 to April 2000. After acid digestion, total metal concentration was determined by inductively coupled plasma optical emission spectrometry (Cd, Cu, Cr, Ni, Zn), flame atomic absorption (Al, Fe, Pb, Mn), or cold vapor atomic absorption spectrometry (Hg). Cr(VI) was complexed with diphenyl-carbazide and detected by UV–vis spectrometry. In order to quantify the risk of exposure, the risk assessment methodology employed by the Environmental Protection Agency of the United States was applied at a screening level. The assumed scenarios included extreme exposure patterns (ingestion of untreated water, conversion of Cr(III) to Cr(VI), temporal peaks of pollution). Fe, Al, Cd, Hg, and Pb were not included in the risk analysis, since they showed a low toxicity potential or were undetected in the samples. The selected metals presented Hazard Quotients < 1, in the following order of increasing risk: Cu < Cr(III) < Zn < Ni < Mn < Cr(VI). Hazard indexes, representing the additive effect of contaminants, were also low in the basin (< 1), but comparatively increased in the lower reach of Feitoria and Cadeia Rivers. Although noncarcinogenic risk levels did not suggest possible adverse toxicological effects to the human population, a considerable deviation from background conditions was observed downstream the area where tanneries are mainly located.  相似文献   
519.
本文提出利用环境功能指数对城市环境功能区的环境功能进行评估,设计了相应的评估方法,以马鞍山市七个环境功能区为例进行了实例分析,讨论了各功能区的环境功能变化趋势,并提出了相应的对策与建议。  相似文献   
520.
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