山区土壤重金属空间插值性能的改进

山区土壤重金属监测中,密集均匀的布点采样困难大,成本高。根据稀疏非均匀样本数据准确预测山区土壤重金属空间分布,对可视化描述检测元素的分布及趋势具有重要意义。基于云南省楚雄市南部山区表层土壤中重金属锰、钒的采样数据,对集成径向基函数神经网络(IRBFANNs)和传统插值方法:反距离(IDW)、普通克里格(OK)、径向基函数神经网络(RBFANNs),进行了不同等级采样密度下的插值性能比较。结果表明,样本点数量减少时,传统预测方法的插值精度都有所下降,而IRBFANNs算法在样本点较少情况下能够保持最好的插值精确度和稳定性,有效改进了空间插值性能。     

水质自动监测在苏州市饮用水源地的应用与思考

以苏州市集中式饮用水源地自动监测系统为例,对该水质自动监测系统的特点、主要功能及在环境管理、蓝藻实时监控等方面的应用作了介绍,并就系统验收、运行管理及系统拓展方面提出了一些对策建议。     

华东某铀矿区稻米中放射性核素铀污染特征及健康风险评价

为查明华东某铀矿区稻米中放射性核素铀污染现状及健康风险问题,测定铀矿区和对照区共136件稻米样品中放射性核素U含量,采用单因子污染指数法评价放射性铀污染,并开展U元素健康风险评价。结果表明:(1)研究区稻米中U含量平均值为1.46 ng·g~(–1),各亚区稻米中U含量平均值从大到小顺序为:开采矿井区水冶场区含矿未采区废弃矿井区江西省背景值对照区;(2)稻米单因子污染指数为1.25,属于轻度污染。其中,开采矿井区和水冶厂区为轻度污染,废弃矿井区和对照区未受污染;(3)首次计算提出江西省大米U元素致癌风险最大斜率系数为1.04×10~3(d·kg)·mg~(–1)。各亚区稻米中成人和儿童致癌风险指数高低顺序均为:开采矿井区水冶厂区含矿未采区废弃矿井区对照区。儿童直接饮食稻米具有一定的致癌风险;开采矿井区和水冶厂区的成人存在一定致癌风险,含矿未采区和废弃矿井区以及对照区均无致癌风险。     

Relationship between cultivated land use functions and land rental behavior of rural households: empirical evidence from different dominant functional regions in central China

This paper analyzes the relationship between the cultivated land use functions and the land rental decisions of rural households in three Dominant Functional Zones of Hubei, China. The results indicate that 41.10% of the rural households in the study areas participated in the land rental market. The land rental market in the Key Development Zone has both a higher participation rate and land rent; the Agricultural Production Zone has a higher participation rate but a lower land rent; and the land rental market in the Key Ecological Zone is underdeveloped. The difference in regional function and economic level leads to a significant difference in the spatial variation of the cultivated land use multifunction. Overall, the cultivated land function of rural households has a significant impact on their land transfer behavior. The higher the Functions of Economic Contribution, Food Production, and Pension & Employment, the more willing the rural households are to rent in the land, while the higher the Function of Inheritance and Retainment of the cultivated land use, the more likely the peasants are to retain their cultivated land resources. Furthermore, the correlation coefficient is significantly higher in the Key Development Zone than in the Key Ecological Zone.     

Low-impact development for impervious surface connectivity mitigation: assessment of directly connected impervious areas (DCIAs)

Urbanization increases directly connected impervious area (DCIA), the impervious area that is hydraulically connected to downstream drainage by closed pipelines. Although the benefits of low-impact development (LID) have been examined in other studies, its effect on alleviating DCIA levels has seldom been assessed. This study measured the DCIA of urban watersheds in Houston, TX, USA. Five land-use types were categorized and the contribution of LID facilities to reducing DCIA in each type was estimated by using Sutherland's equations. The results showed (1) DCIA in commercial areas was greater than that in residential areas, especially for big-box retailers; (2) the percentage of DCIA reduction by LID varied by land-use type; and (3) optimal combinations of LID application could maximize the effectiveness of DCIA reduction. The results contribute to prioritizing land-use type for implementing LID practices and providing local governments with a useful measure to estimate runoff volume.     

工业搬迁区绿化带土壤铜污染及其在植物体内的迁移

老工业搬迁区主要道路两旁绿化带土壤由于历经老工业企业的变迁和环境的污染破坏,可在一定程度上对这一地区环境的历史变迁及重金属污染状况起到指示作用。采集沈阳铁西老工业搬迁区绿化带土壤及其绿化乔木和灌木植株样品,分析土壤中铜的总量及生物有效态含量,同时分别分析了绿化乔木(8种)和绿化灌木(6种)植株根、枝条和叶片的含铜量。结果表明,搬迁区绿化带土壤中含铜量为29.14~166.95mg/kg,显著高于沈阳市土壤铜元素的背景值;土壤有效态铜为0.23~1.72mg/kg,达到中等水平(0.3~1.0mg/kg)的占采样点总数的70.0%。数据还显示,绿化乔木和灌木对铜的蓄积能力依品种不同差异显著,同种植物不同部位(根、枝条和叶片)对铜的富集能力不同;总体上,绿化乔木植株体内含铜量的分布规律为根叶片枝条或叶片根枝条,绿化灌木植株体内含铜量的分布规律为根叶片枝条。对铜蓄积能力较强的绿化乔木为榆叶梅(Amygdalus triloba Lindl.)、垂柳(Salix babylonica Linn.)、旱柳(Salix matsudana Koidz.)和银杏(Ginkgo biloba),对铜蓄积能力较强的绿化灌木为大叶女贞(Ligustrum lucidum Ait.)、小叶女贞(Ligustrum quihoui Carr.)和紫叶小檗(Berberis thunbergii cv.Atropurpurea)。     

某1000 MW燃煤机组脱硝催化剂运行性能检测

以某1000 MW燃煤机组脱硝系统使用的脱硝催化剂为研究对象,分别对不同运行时间的催化剂进行了对比检测。检测结果表明,运行初期,催化剂表面沉积了一定量的碱金属,但属于正常范围内;没有出现过多的硫化合物的沉积;催化剂微观结构遭到一定程度的破坏,比表面积有下降趋势;催化剂机械强度基本保持良好;催化剂活性衰减在正常范围内,催化剂可以继续使用或添加加装层。     

重庆主城区秋冬季逆温对空气质量影响的观测分析

2013年9—11月利用RPG-HATPRO地基多通道微波辐射计对重庆主城区大气进行连续探测,统计了大气逆温情况,并对典型重污染天气下大气逆温与空气质量状况进行综合分析。结果表明,逆温出现的频率为63.3%,基本为接地逆温类型,逆温层厚度为953 m,逆温强度为0.3℃/hm;逆温的存在为气溶胶的积聚和凝聚创造了有利条件。     

Arctic Tipping Points: Governance in Turbulent Times

Interacting forces of climate change and globalization are transforming the Arctic. Triggered by a non-linear shift in sea ice, this transformation has unleashed mounting interest in opportunities to exploit the region’s natural resources as well as growing concern about environmental, economic, and political issues associated with such efforts. This article addresses the implications of this transformation for governance, identifies limitations of existing arrangements, and explores changes needed to meet new demands. It advocates the development of an Arctic regime complex featuring flexibility across issues and adaptability over time along with an enhanced role for the Arctic Council both in conducting policy-relevant assessments and in promoting synergy in interactions among the elements of the emerging Arctic regime complex. The emphasis throughout is on maximizing the fit between the socioecological features of the Arctic and the character of the governance arrangements needed to steer the Arctic toward a sustainable future.     

Bioindication of volatile elements emission by the Puyehue-Cordón Caulle (North Patagonia) volcanic event in 2011

The emission of volatile pollutants from the volcanic eruption of the Puyehue-Cordón Caulle complex (North Patagonia Andean Range) that started in June 4th, 2011, was investigated by bioindication means with the epyphytic fruticose lichen Usnea sp. The elemental composition of pooled samples made up with 10 lichen thalli were analysed by Instrumental Neutron Activation Analysis. Eleven sampling sites were selected within the impacted region at different distance from the volcanic source. Five sites were selected as they were already sampled in a previous study prior to the eruption. Two other new sampling sites were selected from outside the impacted zone to provide non-impacted baseline sites.The elements associated with the lichen incorporation of particulate matter (PM) of geological origin were identified by linear correlation with a geochemical tracer (Sm concentrations). The elements associated with PM uptake were Ce, Eu, Fe, Hf, La, Lu, Na, Nd, Sb, Sc, Se, Ta, Tb, Th, U, and Yb. Arsenic and Cs concentrations showed contributions exceeding the PM fraction in sites near the volcanic centre, also higher than the baseline concentrations, which could be associated with permanent emissions from the geothermal system of the Puyehue-Cordón Caulle complex. The lichen concentrations of Ba, Ca, Co, Hg, K, Rb, Sr, and Zn were not associated with the PM, not showing higher concentrations in the sites nearby the volcanic source or respect to the baseline values either. Therefore, there is no indication of the emission of volatile forms of these elements in the lichen records. The lichen records only identified Br volatile emissions associated with the Puyehue-Cordón Caulle complex eruption in 2011.