医疗废物焚烧厂周边环境空气中二英浓度分布及其健康风险评估

于2015-2018年冬季（12月-2月）对广东省某医疗废物焚烧厂排放烟气及焚烧设施周边2.5 km范围内6个采样点分别进行了4次烟气和环境空气样品采集,应用高分辨气相色谱/高分辨质谱（HRGC-HRMS）联用技术对二（口恶）英（PCDD/Fs）浓度水平进行监测并对其组成特征进行了分析,运用主成分分析法（PCA）对周边环境空气中二（口恶）英来源进行了初步解析,同时采用VLIER-HUMAAN模型评估其对人体的健康风险.结果表明该医疗废物焚烧厂烟气二（口恶）英毒性当量浓度为0.542~21.300 ng·Nm^-3（以I-TEQ计）,排放水平较高;周边环境空气中PCDD/Fs质量浓度和毒性当量浓度变化范围分别为0.682~196.000 pg·m^-3和0.036~17.700 pg·m^-3（以I-TEQ计）,周边环境空气中PCDD/Fs浓度明显受到排放源烟气落地点的影响.空气样品中二（口恶）英同族体及异构体分布指纹谱图与该焚烧设施排放烟气类似,空气质量浓度主要贡献单体以OCDD、1,2,3,4,6,7,8-HpCDF、OCDF以及1,2,3,4,6,7,8-HpCDD为主,主要毒性贡献单体为2,3,4,7,8-PeCDF.PCA源解析结论与指纹谱图特征分析结论基本一致,该研究区域中环境空气二（口恶）英主要来源于医疗废物焚烧烟气排放.健康风险评估结果表明,该区域人群呼吸暴露风险总体处于较为安全的水平（0.0032~0.141 pg TEQ·kg^-1·d^-1）,部分个体的呼吸暴露贡献率超过了评价限值,应引起重视.     

秸秆还田方式对东北农田土壤NH3挥发和N2O排放的影响

秸秆还田是有效利用资源、增加土壤有机质含量和培肥地力的有效措施,但也会影响土壤NH₃挥发和N₂O的排放.探索不同秸秆还田方式对NH₃挥发和N₂O排放的影响对于减少土壤氮素损失和保护生态环境具有重要意义.采用田间小区试验,利用Los Gatos Research（LGR）超便携NH₃分析仪和密闭式静态箱-气相色谱法探究不同秸秆还田方式下土壤NH₃挥发和N₂O排放的特征,试验设4个处理（覆盖还田,即表面覆盖玉米秸秆,0~20和20~40 cm土壤分层扰动后填回,记为JG0-0;常规还田,即秸秆与0~20 cm土壤混合,20~40 cm土壤扰动后填回,记为JG0-20;深还田,秸秆与20~40 cm土壤混合,0~20 cm土壤挖出后填回,记为JG20-40;对照处理,即无玉米秸秆还田,0~20和20~40 cm土壤分层扰动后填回,记为CK）.结果表明:①相比于CK,不同秸秆还田方式均显著降低了土壤NH₃挥发量,增加了土壤N₂O排放量.与CK相比,JG0-0、JG0-20和JG20-40处理下土壤NH₃累积排放量分别减少了12.38%、9.87%和5.73%;土壤N₂O累积排放量分别增加了30.19%、82.82%和36.53%,其中JG0-0和JG20-40处理之间无显著性差异.②JG20-40处理下玉米产量显著高于其他处理,比CK增加了23.15%,JG0-0处理下玉米产量高于CK和JG0-20处理,但并未达到显著水平.③对于NH₃和N₂O这两种气体的总累积排放量,各处理间均达到显著性差异.与CK相比,JG0-0、JG0-20和JG20-40处理下NH₃和N₂O总累积排放量分别增加了16.67%、52.08%和22.92%.④不同秸秆还田方式下的氮素气态损失率均高于CK,JG0-0、JG0-20和JG20-40处理下氮素气态损失率分别比CK增加了17.50%、52.50%和22.50%.因此,综合考虑土壤NH₃挥发量、N₂O排放量和玉米产量等因素,JG0-0处理优于JG20-40、JG0-20处理.      

黄土高原的景观格局变化与水土流失研究——以黄土高原马莲河流域为例

应用RS/GIS技术和景观生态学研究方法,利用通用土壤流失方程(USLE)分析了黄土高原马莲河流域2000年和2007年的景观格局变化与水土流失。结果表明:马莲河流域的景观格局和水土流失方面近8 a发生了重要变化:①建设用地、水域、中高盖度草地以及林地面积增加,低盖度草地、耕地等面积减少,其中超过50%的低盖度草地补充为中高盖度草地;②斑块数量、斑块密度以及多样性指数在减小,说明斑块破碎化程度减小,生态系统趋于稳定化,生态功能逐渐增强;③土壤侵蚀总量减小12 506.76 t,水土流失明显减弱,其变化原因与当地植被恢复、人类活动、人口城镇化、建设用地增加等因素密切相关,尤其是世行项目和国家退耕还林还草政策的有效实施。     

COLD WATER PATCHES IN WARM STREAMS: PHYSICOCHEMICAL CHARACTERISTICS AND THE INFLUENCE OF SHADING1

ABSTRACT: Discrete cold water patches within the surface waters of summer warm streams afford potential thermal refuge for cold water fishes during periods of heat stress. This analysis focused on reach scale heterogeneity in water temperatures as influenced by local influx of cooler subsurface waters. Using field thermal probes and recording thermistors, we identified and characterized cold water patches (at least 3°C colder than ambient streamflow temperatures) potentially serving as thermal refugia for cold water fishes. Among 37 study sites within alluvial valleys of the Grande Ronde basin in northeastern Oregon, we identified cold water patches associated with side channels, alcoves, lateral seeps, and floodplain spring brooks. These types differed with regard to within floodplain position, area, spatial thermal range, substrate, and availability of cover for fish. Experimental shading cooled daily maximum temperatures of surface waters within cold water patches 2 to 4°C, indicating a strong influence of riparian vegetation on the expression of cold water patch thermal characteristics. Strong vertical temperature gradients associated with heating of surface layers of cold water patches exposed to solar radiation, superimposed upon vertical gradients in dissolved oxygen, can partially restrict suitable refuge volumes for stream salmonids within cold water patches.     

区域声环境质量污染水平预测方法评价与对比研究

为完成北京市“十二五”城市区域的主要声污染防治工作目标,全面提高北京市声环境质量水平,科学预测区域内在“十二五”期间噪声污染水平和发展趋势,本文以北京市某典型区域作为研究对象,在收集大量相关资料与实测历史噪声数据的基础上,运用指数平滑法与灰色模型GM（1,1）对所选定研究区域的噪声污染水平与发展趋势进行预测与分析。研究结果表明：运用指数平滑法与灰色模型对研究区域声环境噪声污染预测是可行的,北京市在“十二五”期间声环境质量水平符合《声环境质量标准》（GB3096—2008）中的一类区域标准。     

HPA／ZnFe2O4-TiO2光催化剂的制备及对马拉硫磷的可见光降解

以纳米TiO2载体,利用浸渍法制备了HPA／ZnFe2O4-TiO2光催化剂。对制备的催化剂进行了XRD、BET、TEM和UV-vis DRS表征。结果表明,催化剂样品均为锐钛矿相且ZnFe2O4很好地分散在载体表面,HPA／ZnFe2O4-TiO2光催化荆的平均粒径为10nm且在380-670nm均有强的光响应;反应最佳的HPA浓度为O.08molfL,最佳的ZnFe2O4负载量为1％。考察了HPA溶液初始浓度、ZnFe2O4负载量、溶液初始pH值、H2O2用量、催化剂用量对催化剂活性的影响。在溶液初始pH=13,H2O2=6mmol／L,催化剂用量为2g/L的最优条件下,光照反应进行100min后,马拉硫磷的降解率可达87％;重复4次后马拉硫磷的降解率仍可以达到67％。     

红壤丘陵区晚稻生长期间CO2的排放与固定规律

采用静态箱法对红壤丘陵区稻田生态系统CO2排放与固定进行定位观测.结果表明,晚稻生长期间稻田生态系统CO2通量的日变化随天气条件(晴天、雨天、阴天)的变化而变化,CO2日净固定量在晚稻生长期间波动性很大,最高达10.35 g·m-2·d-1,在晚稻成熟期表现为CO2负固定,为-0.92 g·m-2·d-1;整个晚稻生育期,稻田生态系统CO2累积排放量和土壤呼吸CO2排放量分别为20.4和6.3 t·hm-2,稻田生态系统CO2累积排放量与水稻生物量之间存在极显著幂函数关系.在整个晚稻生育期,稻田生态系统从大气中吸收碳量为3.85 ～4.00 t·hm-2.     

Modelling N mineralization from green manure and farmyard manure from a laboratory incubation study

Predicting N mineralization from organic manures like farmyard manure (FYM) is more difficult than from fresh organic materials like crop residues, as the manures vary greatly in composition. A laboratory incubation experiment was carried out for 98 days at 30 °C under aerobic conditions to study the effects on N dynamics of Gliricidia (Gliricidia sepium, Jacquin) and FYM application to soil at 5 and 10 g kg⁻¹. Application of Gliricidia induced N mineralization from the start of incubation period, with the amount of N mineralized increasing with rate of application. In contrast, application of FYM resulted in immobilization of mineral N in soil, irrespective of the rate of application. The initial net immobilization from FYM was limited by availability of N in the soil for the higher rate of application.We used the APSIM SoilN module to simulate these contrasting patterns of mineralization of N from Gliricidia and from FYM. The prediction of N mineralized from Gliricidia was better than FYM. The default model parameters specify that the fresh organic matter pools (FPOOL1, FPOOL2 and FPOOL3) have the same C:N ratio and this assumption was ineffective in predicting N mineralized from FYM. The predictive ability of the model improved when this default assumption was modified based on the size of the individual pools (FPOOL1, FPOOL2 and FPOOL3), and the pool's C:N ratios. The modelling efficiency, a measure of goodness of fit between the simulated and observed data, improved markedly for the modified model. The discrepancy between the modelled and observed data was a tendency for the model to underestimate the rate of re-mineralization at the lower rate of application of FYM in the later part of incubation. Unfortunately the appropriate modification to the size and C:N ratios of the FPOOLs could not be determined on the basis of chemical analysis alone. Thus, a true predictive application of the model to a new FYM material is not yet possible.     

珠江三角洲城市雨水的化学组成及其成因探讨

于2005—2007年间,基于降水过程监测分析了广州市和珠海市雨水的化学组成。结果表明,广州市雨水的pH值变化于3.32~7.03之间,平均值为4.35,众数约为4.15。珠海市雨水的pH值变化于3.38~6.49之间,平均值为4.51。雨水pH值随降水强度的减弱而降低,这决定于大气中水汽与酸性气体的接触时间。珠江三角洲城市雨水中所含主要离子依次是SO42-、NO3-、NH4＋、Ca2＋、Cl-。雨水的酸化与降水过程密切相关。降雨初期雨水比中后期雨水的pH值高,揭示降雨初期大气中的粉尘颗粒有效中和雨水的酸度。多天连续降水天气对大气尘埃的清洗作用明显,但是持续的SO2和NOx排放更容易使雨水酸化。滨海城市降水初期雨水的电导率上升较快（可以从小于1μS.cm-1上升到20~30μS.cm-1）,随着降水时间的延长雨水的电导率以较慢的速率上升。     

Progress and challenges in consolidating the management of Amazonian protected areas and indigenous territories

Effective management refers to the ability of a protected area or indigenous territory to meet its objectives, particularly as they relate to the protection of biodiversity and forest cover. Effective management is achieved through a process of consolidation, which among other things requires legally protecting sites, integrating sites into land‐use planning, developing and implementing management and resource‐use plans, and securing long‐term funding to pay for recurrent costs. Effectively managing all protected areas and indigenous territories in the Amazon may be needed to avoid a deforestation tipping point beyond which regional climatic feedbacks and global climate change interact to catalyze irreversible drying and savannization of large areas. At present, protected areas and indigenous territories cover 45.5% (3.55 million km²) of the Amazon, most of the 60–70% forest cover required to maintain hydrologic and climatic function. Three independent evaluations of a long‐term large‐scale philanthropic initiative in the Amazon yielded insights into the challenges and advances toward achieving effective management of protected areas and indigenous territories. Over the life of the initiative, management of sites has improved considerably, particularly with respect to management planning and capacity building, but few sites are effectively managed and many lack sufficient long‐term financing, adequate governance, support of nongovernmental organizations, and the means to withstand economic pressures. The time and money required to complete consolidation is still poorly understood, but it is clear that philanthropic funding is critical so long as essential funding needs are not met by governments and other sources, which could be on the order of decades. Despite challenges, it is encouraging that legal protection has expanded greatly and management of sites is improving steadily. Management of protected areas in other developing countries could be informed by improvements that have occurred in Amazonian countries.