Modelling global-scale potential grassland changes in spatio-temporal patterns to global climate change

Grassland is one of the most widespread vegetation types worldwide and plays a significant role in global carbon cycling. Understanding the sensitivity of grassland to climate change and the effect of climate changes on the grassland ecosystems is a key issue in global carbon cycling. One of the goals of this study was to evaluate the three net primary productivity (NPP)–climate models, i.e. the Miami model, the Schuur model and the classification indices-based model. Results indicated that the classification indices-based model was the most effective model at estimating large-scale grassland NPP. In this research, changes in the spatial pattern of global potential grassland from recent past (1950–2000) to future (2001–2050) A2a scenario were analysed with the integrated orderly classification system of grassland (IOCSG) approach in a Geographic Information System (GIS) environment. NPP was evaluated with the classification indices-based model. Results indicate that under recent past climatic conditions, the main parts of global grassland are the savanna and tundra and alpine grassland and will be converted into the savanna, steppe and semi-desert grassland in A2a scenario. As a whole, areas of grassland will increase by 31.76 million hectares. The classification indices-based model estimated a 12.40% increase of total NPP in grassland from recent past to A2a scenario. It will impose a new issue for future grassland researches to support sustainable development and to provide action relevant knowledge to meet the challenge of climate change.     

菊花茶中砷含量特征及砷健康风险评价

菊花茶是深受人们喜爱的一种饮品,但其干燥过程及加工工艺不当会造成菊花茶的重金属污染,尤其是和硫磺矿伴生的重金属砷。以市售菊花茶为研究对象,采用硝酸-双氧水消解体系,高压密闭消解系统和原子荧光光谱法分析测定了其中砷(As)含量,对典型超标菊花茶样品进行不同冲泡方式的筛选,确定其适宜的饮用方式,并根据我国绿色代用茶行业标准和WHO砷最大日允许摄入量(ADI)对菊花茶中砷的人体健康风险做出评价。结果表明,菊花茶中砷的含量范围在0.01～3.52mg·kg-1,91.1%的样品符合绿色代用茶的《中华人民共和国农业行业标准》(0.5mg·kg-1),其中砷含量最高的为药用祁菊花达3.52mg·kg-1,所有样品中超标的8个菊花茶样品种类分别为祁白菊(2个),杭白菊(2个),黄山贡菊(1个)和野菊花(1个),怀菊和药用祁菊各1个,75%的超标样品为散装饮品;选择超标的2个典型菊花茶样品(杭白菊和药用祁菊花)进行冲泡方式筛选,得出适宜的饮用方式为:用水茶质量比例为25∶1的开水清洗菊花茶5min,然后用开水冲泡5～20min再饮用。随菊花茶进入人体的最大日摄入量(极限值)为43.7～169μg·d-1,其占ADI(allowable daily intake)的比值范围在34.1%～132%,其中随药用祁菊花进入人体的As最大日摄入量与ADI的比值超过100%,这表明砷经菊花茶饮品摄入人体内所潜在的健康风险不容忽视。砷超标的菊花茶经过冲泡后饮用,砷的人体日摄入量13.1～36.3μg·d-1,其占ADI的比值范围在10.3%～28.4%。因此,经过洗茶后再冲泡饮用,砷的日摄入量显著降低(P<0.01),建议饮用菊花茶时洗1次茶后再冲泡饮用。     

Quantification of TiO2 and ZnO nanoparticles in wastewater using inductively coupled plasma optical emission spectrometry

Abstract

The applicability of inductively coupled plasma optical emission spectrometry has been examined for determination titanium dioxide and zinc oxide nanoparticles in industrial wastewater samples. The extraction and preconcentration of the nanoparticles were achieved using ligandless ultrasound-assisted surfactant-based dispersive liquid–liquid microextraction. Under optimized conditions, the developed method had limits of detection (LOD) of 2.7?ng L^?1 for Ti and 3.6?ng L^?1 for Zn resulting from dissolved TiO₂ and ZnO nanoparticles. The relative standard deviation values for intraday precision were 2.5% and 3.1% for TiO₂ and ZnO, while the interday precision was 4.5% and 5.0%. Percentage recoveries ranging from 98% to 100% were obtained. Finally, the applicability of the method was examined by analyzing spiked samples and wastewater samples collected from textile, cosmetic and paint industries.     

盐沼植物群落研究进展：分布、演替及影响因子

盐沼是全球温带及亚热带地区的主要滨海湿地类型之一,在我国分布广泛。盐沼湿地生态系统敏感、脆弱且具有重要的生态系统服务功能。理解盐沼植物群落时空分布动态的一般规律与生态学机制,是开展盐沼生态系统研究的基础与关键。海陆交界的特殊环境特征是影响盐沼湿地植物群落的空间分布及演替过程的主要因素。在海洋潮汐作用下,盐沼湿地中的盐度、水淹强度、氧化还原电位等非生物因子往往呈梯度分布,这也导致了生物群落中种内、种间关系的变化。在非生物及生物因子的共同作用下,盐沼植物群落也往往沿高程梯度呈带状分布。环境变化是盐沼植物群落演替的驱动因素,在海岸线相对较为稳定的盐沼,植物群落的演替多属自发演替,而在靠近的大型河口的一些持续淤涨的盐沼,植物群落演替通常属于异发演替。沿海地区的水产业、流域上游及沿海地区的工程、污染及生物入侵等直接或间接的人类活动已对盐沼湿地植物群落的产生了深刻影响。经过数十年发展,国际上盐沼植物群落学研究的热点领域主要包括盐沼植物群落与其他生物群落的相互关系、植物群落在盐沼生态系统过程中的作用等。在全球变化背景下,盐沼植物群落对气候变化与海平面升高也日益成为盐沼植物群落学相关的热点。     

Indoor carbonyl compounds in an academic building in Beijing, China: concentrations and influencing factors

Carbonyl compounds in indoor air are of great concern for their adverse health effects. Between February and May, 2009, concentrations of 13 carbonyl compounds were measured in an academic building in Beijing, China. Total concentration of the detected carbonyls ranged from 20.7 to 189.1 μg·m^-3, and among them acetone and formaldehyde were the most abundant, with mean concentrations of 26.4 and 22.6 μg·m^-3, respectively. Average indoor concentrations of other carbonyls were below 10 μg·m^-3. Principal component analysis identified a combined effect of common indoor carbonyl sources and ventilation on indoor carbonyl levels. Diurnal variations of the carbonyl compounds were investigated in one office room, and carbonyl concentrations tended to be lower in the daytime than at night, due to enhanced ventilation. Average concentrations of carbonyl compounds in the office room were generally higher in early May than in late February, indicating the influence of temperature. Carbonyl source emission rates from both the room and human occupants were estimated during two lectures, based on one-compartment mass balance model. The influence of human occupants on indoor carbonyl concentrations varies with environmental conditions, and may become significant in the case of a large human occupancy.     

基于差错分类框架辨识人为差错

为解决人因可靠性分析中的人为差错辨识问题,提出新的工作流程。在该流程中,由人为差错引导词引导,以自问自答方式开展差错辨识工作。针对动作和决策2种差错类型,分别设计差错基本分类框架。其中,动作差错基本分类框架包括5个差错大类,10个差错小类;决策差错基本分类框架包括2个差错大类,10个差错小类。这些差错小类可作为差错辨识过程中的引导词。通过2个实例,演示这2个框架在差错辨识过程中的作用。演示结果表明,在人为差错引导词引导下开展差错辨识工作,更容易保证差错辨识结果的全面性和一致性。     

通用桥式起重机驾驶员操作可靠度研究

为有效改善桥式起重机驾驶员的操作水平,通过分析和确定这种起重机的工作流程,建立驾驶员基本动作序列。采用第二代人因可靠性分析(HRA)模型,按正常工作状态与紧急工作状态2种情况,对驾驶员操作可靠度进行全面、定量的分析与研究。结果表明,驾驶员操作可靠度定量研究中,重要的是要考虑起重机机型和基本操作动作序列、工作状态、动作时间、人机工效、作业环境等复杂因素。建立驾驶室人机工效定量分析与评价机制,加强驾驶员专业教育培训及考核制度、改善工作环境等技术措施,从根本上提高驾驶员操作可靠度等级,才能符合起重机械安全的发展趋势。     

掘进工作面复杂环境因素与人因伤亡事故的关联度分析

为探究煤矿掘进工作面的温度、湿度、噪声、照度、粉尘等环境因素对人因伤亡事故发生的影响,进一步明确不同类型的人因伤亡事故与各环境因素之间的关系,针对人因伤亡事故的发生与各环境因素之间不具有确定的线性关系,而是具有灰色系统的特点,运用灰色关联分析方法建立了不同类型人因伤亡事故与环境因素之间的灰色关系模型,分析了掘进工作面不同类型的人因伤亡事故与各环境因素之间关联程度的大小。结果表明,在煤矿掘进工作面的温度、湿度、噪声、照度、粉尘5个环境因素中,温度是影响掘进工作面人因伤亡事故的最主要因素,其次是光照,再次是温度。     

环境激素的内分泌干扰机制及其对人体的影响

环境激素问题的调查研究标志着地球环境时代的到来。重点讨论了环境激素的分类、特征及其内分泌干扰机制,并涉及了环境激素对人体的影响,以期引起人们的关注和重视,加强这方面的调查研究。     

基于多源遥感信息的人为热排放量空间化——以浙江省为例

基于自上而下能源清单法,主要考虑工业、交通、建筑和人体新陈代谢这4个热源对人为热的贡献,估算了2010年浙江省68个县市的人为热排放总量.使用DMSP/OLS遥感夜间灯光数据以及阈值法提取出人为热排放的主要区域,并有效减少夜灯像元溢出效应的影响.利用夜间灯光数据和增强型植被指数(EVI)构建人居指数,基于各市县人为热排放总量与其行政区范围内人居指数累计值之间很强的相关关系建立人为热排放量空间化模型,获得了250m分辨率下浙江省2010年城市人为热通量的空间分布.结果显示浙江省各县市的平均人为热排放通量为5.5W/m²,城市高值区一般介于10~40W/m².栅格化的人为热数据可以为城市气候环境的数值模拟研究提供基础数据支持.