南极菲尔德斯半岛植被土壤N2O排放特征

应用密闭箱法首次测定了南极菲尔德斯半岛苔藓、地衣植被土壤N2O的排放通量,并估算了该半岛植被区土壤在夏季2个月内N₂O的排放总量.结果表明:在晴天和雨天,苔藓土壤N₂O的排放通量与温度有较好的响应关系,呈现单峰型变化趋势;但在雪天,与温度的变化不一致;苔藓、地衣这2种不同的植被土壤N2O排放通量日变化基本一致;温度是影响苔藓土壤N2O的排放通量季节变化的主要因子,同时还受降水的影响,干湿交替有利于N2O的排放;苔藓土壤N₂O的排放总量为3.7152kg;地衣土壤N₂O的排放总量为2.5344kg.由此可见,南极菲尔德斯半岛苔藓、地衣植被土壤N₂O排放量虽然很小,但仍起着大气N₂O源的作用.     

双硫腙法研究废电池中汞的分布及浸出

用双硫腙法测定了几种废电池中汞的含量和分布及在不同水环境条件下,汞的浸出率,试图为废电池中各组分去汞后的回收提供理论依据。结果表明,双硫腙测定废电池中汞的方法是可靠的;汞在废电池中主要分布在锌皮（锌粉）和碳包部分;pH对汞的浸出率有较大的影响,浸出率与pH呈负相关。     

砷胁迫下水磷耦合对不同磷效率水稻根表铁膜及其各部位砷含量的影响

为探索缓解水稻砷毒害的农艺措施,以耐低磷水稻99011和低磷敏感水稻99012为材料,通过土培试验,研究水分、磷用量及其交互作用对不同砷浓度酸性土壤中水稻根表铁膜以及植物体内砷分配的影响。结果表明,节水灌溉(干湿交替)明显减少水稻根表铁膜量,降低铁膜、根系、秸秆、颖壳和精米中的砷含量。与30mg·kg-1P2O5相比,180mg·kg-1P2O5能明显减少两个品种水稻的根表铁膜量以及根系和秸秆中的砷含量;对耐低磷品种铁膜砷含量影响不大,但显著降低磷敏感品种铁膜砷含量;在50mg·kg-1砷处理中增加磷用量对水稻颖壳砷含量影响不大,在100mg·kg-1砷处理时能显著降低颖壳砷含量;增加磷用量可明显增加耐低磷品种的精米砷含量,降低磷敏感品种的精米砷含量。水、磷交互效应主要受水分效应的影响。加砷处理后,相同处理下耐低磷品种的根表铁膜量和铁膜中的砷含量显著高于磷敏感品种,而根系、秸秆、颖壳和精米中的砷含量则相反。研究表明,可以通过节水灌溉,并根据砷污染程度和植物磷营养特性确定适当的磷肥用量,从而减少砷在水稻体内的累积,提高食品安全。     

我国10城市冬季大气颗粒物中多环芳烃污染及呼吸暴露风险评价

大气中颗粒物和多环芳烃对环境与人体健康危害较大,已引起社会各界的广泛关注。以我国10个城市2013年12月和2014年1月大气中空气动力学直径小于10μm的颗粒物(PM10)为研究对象,采用硅胶-氧化铝层析柱净化分离、气质联用仪分析的方法测定了27种多环芳烃(PAHs)的浓度水平,分析其谱分布及空间分布,并通过呼吸暴露途径估算了癌症病发增量(ILCRs)和人群归因危险度百分比(PAF)。结果表明,27种物质的总浓度为13.72~2 002 ng·m-3;在10个城市中晋中总浓度最高,厦门最低。PAHs空间污染水平呈现北方高于南方、东部沿海城市浓度相对较低的趋势。温度与总浓度有相关性。在27种PAHs中,占主导地位的单体为荧蒽(FLA,7.56%~19.8%),芘(PYR,6.72%~13.8%),艹屈(CHR,12.8%~19.6%)和苯并(k)荧蒽(Bk F,8.59%~15.5%),4者占到多环芳烃总浓度的42.1%~64.3%。根据研究区域苯并[a]芘(Ba P)人口加权浓度估算ILCRs范围为8.94×10-6~4.77×10-4,据此计算的PAFs为0.487%~13.2%,均值为3.44%,高于全国平均水平1.6%。上述研究结果为大气颗粒物中PAHs的研究提供重要的数据基础。     

Taxonomic structure and potential nitrogen metabolism of microbial assemblage in a large hypereutrophic steppe lake

Recent studies have expanded the interests about microbial community and function following the rapid development of high-throughput sequencing techniques in the freshwater ecosystem. In this study, we aimed to attain a deep understanding of microbial community structure and potential nitrogen metabolism in Hulun Lake, a shallow hypereutrophic steppe lake in the Mongolian Plateau in China. The result demonstrated that cyanobacteria were the most dominant phylum. Network analysis showed both intra- and inter-phylum co-occurrence were pervasive, and there were modular structures in the microbial assemblages. The cluster dominated by proteobacteria was mainly negatively connected to the cluster dominated by both proteobacteria and actinobacteria. Cyanobacteria were tightly clustered together and positively connected to these two clusters. The major nitrogen metabolism pathways were glutamine synthetase–glutamate synthase and assimilatory nitrate reduction, indicating the nitrogen was mainly retained in the lake by microbial uptake. Cyanobacteria contributed 43.25% gene reads involved in the overall nitrogen metabolism but mainly contributed to assimilatory nitrate reduction and nitrogen fixation, aggravating the lake eutrophication. This study adds to our knowledge of microbial assemblages and nitrogen metabolism in the shallow hypereutrophic lake and provided an insight understanding for the purposes of lake ecosystem’s protection and efficient management in the Mongolian Plateau.

     

Impacts of Human Behavioral Heterogeneity on the Benefits of Probabilistic Flood Warnings: An Agent‐Based Modeling Framework

Flood forecasts and warnings are intended to reduce flood‐related property damages and loss of human life. Considerable research has improved flood forecasting accuracy (e.g., more accurate prediction of the occurrence of flood events) and lead time. However, the delivery of improved forecast information alone is not necessarily sufficient to reduce flood damage and loss of life, as people have varying responses and reactions to flood warnings. This study develops an agent‐based modeling framework that evaluates the impacts of heterogeneity in human behaviors (i.e., variation in behaviors in response to flood warnings), as well as residential density, on the benefits of flood warnings. The framework is coupled with a traffic model to simulate evacuation processes within a road network under various flood warning scenarios. The results show the marginal benefit associated with providing better flood warnings is significantly constrained if people behave in a more risk‐tolerant manner, especially in high‐density residential areas. The results also show significant impacts of human behavioral heterogeneity on the benefits of flood warnings, and thus stress the importance of considering human behavioral heterogeneity in simulating flood warning‐response systems. Further study is suggested to more accurately model human responses and behavioral heterogeneity, as well as to include more attributes of residential areas to estimate and improve the benefits of flood warnings.     

Farm‐level Economic and Water Quality Impacts of Comprehensive Nutrient Management Plan Implementation in the Ohio River Basin

In this article, we provide an assessment of comprehensive nutrient management plans (CNMPs) as a tool for addressing nonpoint nutrient and sediment losses from the animal feeding operations (AFOs) in the Ohio River Basin. We employ a macro modeling system to determine the aggregate economic and water quality impacts of CNMP implementation on AFOs in the entire basin. Results of the study indicate that implementing CNMPs on AFOs will help reduce sediment and organic nutrient losses from their current levels at moderate cost. The flexibility inherent in CNMP designs means farmers may be able to achieve water quality and other conservation goals at less cost with CNMPs than with other less flexible policy options.     

CO还原脱硝反应锌铜双金属有机骨架催化剂的制备

采用离子交换法制备锌铜双金属有机骨架(Zna/HKUST-1,a=1/24,1/12,1/6,1/3,a为Zn与Cu的摩尔比),用于催化CO还原脱硝反应。采用XRD,SEM,FTIR,H2-TPR,BET等方法对Zna/HKUST-1进行了表征。表征结果表明:Zna/HKUST-1中有明显的Zn—O键和铜基金属有机骨架(HKUST-1)的结构,证明Zn成功进入了HKUST-1中;但随a的不同,Zna/HKUST-1的形貌、大小及比表面积出现了差异。实验结果表明,Zna/HKUST-1(a=1/24)对CO还原脱硝反应的催化活性最高,可在230℃达到NO转化率100%。     

Review of efficiencies of cogeneration units using internal combustion engines

The most frequently used technology in cogeneration units up to 10 MWe are internal combustion engines and the majority of the models are up to 500 kWe. There are dozens of reciprocating internal combustion engine–based cogeneration unit manufacturers and more than hundred suppliers in the market. In the article, data from supplier technical specifications of 583 units (34 manufacturers) is collected and analyzed. The authors proposed mathematical relations that show dependence of efficiencies on electric power that can be used for initial feasibility studies. Authors also have showed that value of 0.75 for power-to-heat ratio (proposed by EU Directive 2004/8/EC) does not always correspond to current market situation.     

Sustainable farming practices of the Chinese mitten crab (<Emphasis Type="Italic">Eriocheir sinensis)</Emphasis> around Hongze Lake,lower Yangtze River Basin,China

Results of a survey of 156 Chinese mitten crab (Eriocheir sinensis) grow-out farms around Hongze Lake (118.48–118.72°E; 33.36–33.38°N) are reported. Area farmed has remained relatively unchanged but production (59 932 t in 2012) increased steadily over the last 7 years, indicative of the viability and sustainability of the farming system that has gradually replaced intensive Chinese major carp polyculture around Hongze Lake. Results showed that production range was 135–2400 kg ha⁻¹ cycle⁻¹ (mean 1144 ± 34). Crab yields correlated linearly to stocking density and conformed to a normal distribution curve, with 66.7 % of farms yielding 900 kg ha⁻¹ cycle⁻¹ or more. Yield was negatively correlated to pond size and capture size (p < 0.01), and farms with macrophyte coverage rate lower than 30 % of water surface were significantly (p < 0.05) lower than those exceeding 30 %.

Electronic supplementary material

The online version of this article (doi:10.1007/s13280-015-0722-0) contains supplementary material, which is available to authorized users.