岩溶区地下水补给型水库表层无机碳时空变化特征及影响因素

为更深入地认识岩溶区地下水补给型水库表层无机碳的循环过程,于2014-07-12~2014-07-20期间,以广西上林县大龙洞岩溶水库表层水体为研究体系,对无机碳循环研究的重要指标进行定点观测和高密度的昼夜监测.结果发现:1从上游到下游DIC含量和水体p CO2值逐渐增加[DIC(平均):122.88 mg·L-1增至172.02 mg·L-1,p CO2(平均):637.91×10-6增至1 399.97×10-6],δ13CDIC值逐渐偏负[δ13CDIC(平均):-4.34‰降至-6.97‰].2库区均为大气CO2的源,CO2交换通量在7.11~335.54 mg·(m2·h)-1之间,平均125.03 mg·(m2·h)-1,上游和下游地区CO2交换通量较大[平均131.73 mg·(m2·h)-1、170.25 mg·(m2·h)-1],中游狭窄地区CO2交换通量较小[平均116.05 mg·(m2·h)-1].3表层水体p CO2值和水-气界面CO2交换通量存在晚上升高,白天降低的昼夜变化规律,且与叶绿素a(Chla)呈负相关关系.分析认为:1大龙洞水库表层水体DIC含量、δ13CDIC值和水体p CO2的空间分布主要受浮游植物浓度、浊度、电导率、水深、透明度等的影响,而水-气界面CO2交换通量除了受浮游植物浓度空间变化的影响外还受风速的影响.2浮游植物昼夜垂向运动及光合作用和呼吸作用昼夜变化控制着水库表层水体溶解性无机碳的昼夜循环过程.     

夏季珠江三角洲地区PM2.5化学组分特征及其对大气能见度的影响

于2010年夏季在珠三角主要城市广州、佛山、东莞、深圳、珠海以及广州郊区从化同步采集PM2.5样品,利用热光反射碳分析仪和离子色谱分别分析样品中有机碳/元素碳和水溶性离子浓度,并同步收集能见度和气象数据.在此基础上对珠三角主要城市大气PM2.5中主要化学成分的浓度水平和空间分布特征进行分析,并利用IMPROVE方程重建大气消光系数,探讨PM2.5的主要化学组分对大气能见度的影响.结果发现,观测期间珠三角地区PM2.5中的主要化学成分空间分布特征明显,广州、佛山和东莞浓度较高,珠海和深圳浓度较低.(NH4)2SO4、有机物(OM)、EC和NH4NO3对夏季珠三角大气消光系数贡献率分别为39%、31%、12%和13%.     

基于实际道路交通流信息的北京市机动车排放特征

通过模型模拟和调查统计方法获取了北京路网的车流量、车型构成和车速基础数据.基于具有时空分布特征的实际道路交通流信息和排放因子,以Arc GIS为平台构建了北京市机动车尾气排放清单,并分析实际道路排放特征及污染物排放的空间分布特征.结果表明,北京市城区各类型道路上小客车比例均在89%以上,郊区道路也为小客车比例最高,但小货车、中货车、大货车、大客车、拖拉机和摩托车均占一定比例.污染物排放强度与车流量呈正相关性,污染物排放强度总体上呈现白天高夜间底的趋势,但是郊区道路PM排放昼夜变化趋势不明显,高速路的PM排放强度夜间大于白天.污染物排放的空间分布为城区、南部、东南以及东北部接近城区的区域排放强度较高,西部山区及北部山区由于路网密度较小排放强度较低,城区环路和郊区高速公路附近由于车流量大,排放强度较高.     

深圳近岸海域全氟化合物的污染特征

为探究深圳近岸海域全氟化合物(perfluorinated compounds,PFCs)的污染特征,2013年9月采集了深圳近岸(离岸﹥2km)10份表层海水和7份表层沉积物.采用固相萃取分离、富集,结合高效液相色谱-质谱联用的方法测定了其中16种PFCs的含量.结果表明,表层海水中有10种PFCs不同程度地检出,包括C4、C6和C8全氟磺酸盐(perfluorinated sulfonates,PFSAs)和C5~C11全氟羧酸(perfluorinated carboxylic acids,PFCAs).ΣPFCs质量浓度范围在1.74~14.7 ng·L-1之间,其中PFBS、PFOS和PFOA是主要的PFCs.ΣPFCs质量浓度分布呈西高东低的态势,伶仃洋和深圳湾ΣPFCs质量浓度显著高于大亚湾和大鹏湾(P0.05),距岸越远ΣPFCs质量浓度越低.表层海水中PFCs可能主要来自于近岸污水的排放以及河流入海的输入.表层沉积物中有8种PFCs不同程度地检出,包括C6和C8PFSAs和C5,C6,C8~C11PFCAs.ΣPFCs含量范围在2.22~2.62μg·kg-1之间,其中PFOS是主要的PFCs.ΣPFCs含量变化很小,可能主要来自对上覆海水中PFCs的吸附.沉积物吸附PFCs的能力随碳链长度增加而增强,且相同碳链长度的情况下,PFSAs较PFCAs更易于被吸附.此外,不同近岸海域PFCs质量浓度比较结果表明,深圳近岸海域表层海水PFBS污染较为严重,而沉积物PFOS含量与其他海域相差不大.     

基于氢氧稳定同位素的黄土高原云下二次蒸发效应

根据GNIP提供的1985年1月至2004年12月黄土高原8个站点的409个降水同位素数据及同期的气象资料,结合HYSPLIT 4.9模型,分析了该区δ18O和d的时空分布特征,计算了二次蒸发的比率,并对不同气象因子影响二次蒸发的程度作了探讨,得到以下结论:1冬季风和夏季风期间,在黄土高原内由南向北δ18O呈上升趋势,d呈下降趋势;自东向西δ18O仅在夏季风期间有上升趋势,而在冬季风期间呈现下降趋势,d总呈现下降的趋势,δ18O和d的变化幅度可以指示季风的路径.2该区全年存在二次蒸发效应,夏季风期间最为明显,蒸发比率介于1.51%~5.88%之间,平均值为3.87%.冬季风期间蒸发比率总体较低,介于1.06%~5.46%之间,平均值也降为3.03%.黄土高原边缘站点蒸发比率受季风变化影响较大,而中部站点受季风变化影响较小.3温度对二次蒸发的影响较大,降水量和水汽压其次,相对湿度较小.此外,风速和海拔对二次蒸发的影响较弱.     

济南市大气污染时空特征研究

为不断改善济南市大气环境质量,在广泛收集与整理相关资料和数据基础上,基于综合污染指数评价法及Arc-GIS平台空间插值法研究并表征了济南市“十一五”期间大气主要污染物的时、空变化特征及发展趋势;研究结果表明：济南市“十一五”期间大气环境质量变化较大,2007～2009年污染较为严重,之后有所改善;大气污染物浓度呈明显的季节变化特征,冬季污染最严重,夏季空气质量最好;首要污染物为PM10;污染较严重区域集中在济南市东北部地区;其变化原因受地理气候条件、产业结构和能源结构影响较大.该研究方法及结论对其他大中城市大气环境质量时空变化研究具有一定借鉴价值.     

Phosphorus sorption capacities in a headstream landscape The pond chain structure

Understanding phosphorus sorption phenomena in different wetland sediments is important in controlling the P output in headstream watersheds. The pond chain structure （PCS） is widespread in the headstream agricultural watersheds in the southeast of China. Phosphorus sorption characteristics were determined for pond surface sediments （0-12 cm） along a pond chain structure in Liuchahe watershed of Chaohu Lake. Results showed that P sorption capacities （expressed by P sorption index （PSI）） varied both with the landscape position of the ponds and sediment depth. From foothill ponds to riverside ponds the P sorption capacities indicated a significant gradient variability. The higher elevation ponds showed greater sorption capacities, and with the pond elevation decline, P sorption capacities gradually decreased. Some physico-chemical properties, such as pH, oxalate-extractable Fe （Feox）, organic matter （TOC） and Mehlich l-extractable Ca, Mg of pond sediments also indicated significant gradient variability from high elevation ponds to low elevation ponds. Feox was the sediment parameters most highly positively correlated with PSI and was the key factor in controlling P sorption capacity in the pond chain structure （r=0.92, p〈0.001）. Long-term hydrologic and sediment inputs can affect the distribution of sediment constituents and further affect the P sorption capacity. Making the best of the spatial difference of sorption capacities of ponds in watersheds to control nonpoint source P pollutant is necessary.     

Arsenic, Cadmium, Lead, and Mercury in surface soils, Pueblo, Colorado: implications for population health risk

Decades of intensive industrial and agricultural practices as well as rapid urbanization have left communities like Pueblo, Colorado facing potential health threats from pollution of its soils, air, water and food supply. To address such concerns about environmental contamination, we conducted an urban geochemical study of the city of Pueblo to offer insights into the potential chemical hazards in soil and inform priorities for future health studies and population interventions aimed at reducing exposures to inorganic substances. The current study characterizes the environmental landscape of Pueblo in terms of heavy metals, and relates this to population distributions. Soil was sampled within the city along transects and analyzed for arsenic (As), cadmium (Cd), mercury (Hg) and lead (Pb). We also profiled Pueblo’s communities in terms of their socioeconomic status and demographics. ArcGIS 9.0 was used to perform exploratory spatial data analysis and generate community profiles and prediction maps. The topsoil in Pueblo contains more As, Cd, Hg and Pb than national soil averages, although average Hg content in Pueblo was within reported baseline ranges. The highest levels of As concentrations ranged between 56.6 and 66.5 ppm. Lead concentrations exceeded 300 ppm in several of Pueblo’s residential communities. Elevated levels of lead are concentrated in low-income Hispanic and African-American communities. Areas of excessively high Cd concentration exist around Pueblo, including low income and minority communities, raising additional health and environmental justice concerns. Although the distribution patterns vary by element and may reflect both industrial and non-industrial sources, the study confirms that there is environmental contamination around Pueblo and underscores the need for a comprehensive public health approach to address environmental threats in urban communities.     

基于权重因子模型的建筑荷载作用下地面沉降危险性评价

针对于城市化进程中建筑荷载引发地面沉降的问题,以天津市局部地区为例,应用权重因子模型对其危险性进行了分析和评价。文中根据该区域的建筑物密集程度、建筑的结构和基础形式、土壤物理性质、水文地质条件等基础数据,应用GIS空间分析的方法分别提取了建筑容积率、土壤竖向应力、压缩层厚度、土壤压缩模量、地下水埋深、地下水渗透性六个诱发因子,经过条件独立性测试,将相互独立的因子组合成六种形式,然后,通过统计对比每个因子的权重值进行叠加分析,绘制了危险性分布图,从而进行地面沉降的危险性评价,最后,评价结果通过受试者工作特征曲线(ROC)验证,表明在使用全部因子进行危险性评价的情况下,分析精确度能够达到85.15%,在使用其他因子组合的情况下,分析精度均超过70%,说明这种评价方法具有较高的准确性和适用性。     

Quantifying Loss of Acoustic Communication Space for Right Whales in and around a U.S. National Marine Sanctuary

The effects of chronic exposure to increasing levels of human‐induced underwater noise on marine animal populations reliant on sound for communication are poorly understood. We sought to further develop methods of quantifying the effects of communication masking associated with human‐induced sound on contact‐calling North Atlantic right whales (Eubalaena glacialis) in an ecologically relevant area (～10,000 km²) and time period (peak feeding time). We used an array of temporary, bottom‐mounted, autonomous acoustic recorders in the Stellwagen Bank National Marine Sanctuary to monitor ambient noise levels, measure levels of sound associated with vessels, and detect and locate calling whales. We related wind speed, as recorded by regional oceanographic buoys, to ambient noise levels. We used vessel‐tracking data from the Automatic Identification System to quantify acoustic signatures of large commercial vessels. On the basis of these integrated sound fields, median signal excess (the difference between the signal‐to‐noise ratio and the assumed recognition differential) for contact‐calling right whales was negative (?1 dB) under current ambient noise levels and was further reduced (?2 dB) by the addition of noise from ships. Compared with potential communication space available under historically lower noise conditions, calling right whales may have lost, on average, 63–67% of their communication space. One or more of the 89 calling whales in the study area was exposed to noise levels ≥120 dB re 1 μPa by ships for 20% of the month, and a maximum of 11 whales were exposed to noise at or above this level during a single 10‐min period. These results highlight the limitations of exposure‐threshold (i.e., dose‐response) metrics for assessing chronic anthropogenic noise effects on communication opportunities. Our methods can be used to integrate chronic and wide‐ranging noise effects in emerging ocean‐planning forums that seek to improve management of cumulative effects of noise on marine species and their habitats. Cuantificación de la Pérdida de Espacio de Comunicación Acústica para Ballenas Francas Dentro y Alrededor de un Santuario Marino Nacional en E. U. A.