Fast screening compositions of PM2.5 by ATR-FTIR: Comparison with results from IC andOC/EC analyzers

Chemical speciation of fine particles or PM_(2.5) collected on filters is still a costly and timeconsuming task. In this study, filter-based PM_(2.5) samples were collected during November–December 2013 at four sites in Guangzhou, and the major components were fast screened(~7 min per filter sample) by Attenuated Total Reflectance(ATR)-Fourier Transform Infrared Spectroscopic(FTIR) in comparison with that measured by Organic carbon/Element carbon(OC/EC) analyzer and Ion Chromatography(IC). The concentrations of nitrate, ammonium, sulfate,primary organic carbon(POC) and secondary organic carbon(SOC) measured by OC/EC and IC analyzers were better correlated with their infrared absorption peak heights at 1320 cm~(-1) for nitrate, 1435, 3045 and 3215 cm~(-1) for ammonium, 615 cm~(-1) for sulfate, 690, 760 and 890 cm~(-1) for POC and 1640 and 1660 cm~(-1) for SOC respectively, during polluted days(PM_(2.5) 75 μg/m~3) than during clean days(PM_(2.5)≤ 75 μg/m~3). With the evolution of a haze episode during our field campaign, the concentrations of the major PM_(2.5) components displayed consistent variations with their infrared absorption peak heights, suggesting ATR-FTIR could be a fast and useful technique to characterize filter-based PM_(2.5) compositions particularly during pollution events although cautions should be taken when PM_(2.5) levels are low. Notably, elevated PM_(2.5) mass concentrations occurred with enhanced ratios of [NO_(-3)]/[SO_4~(2-)] and [NH~(+4)]/[SO_4~(2-)], implying that nitrogenous components play vital roles in the PM_(2.5) pollution events in the study region.     

铜仁汞矿区土壤汞污染现状调查研究

为了进一步对废弃汞矿污染区的生态环境进行跟踪调查及科学的评价,2015年通过对铜仁市废弃汞矿区周围的稻田、旱田及菜地土壤汞污染现状调查分析。采用S型随机抽样方式,并使用原子荧光光度法对研究对象进行分析。结果表明:万山镇、云场萍及路腊村汞矿区稻田土壤总汞(THg)含量平均值分别为123.75、79.33、21.89 mg/kg;其旱田土壤THg含量平均值分别为:117.20、73.34、19.90 mg/kg;其菜地土壤THg含量平均值分别为129.40、81.78、26.50 mg/kg;且,万山汞矿区甲基汞(Me Hg)含量平均值分别为6.48(稻田)、4.80(旱田)、6.40μg/kg(菜地);云场萍汞矿区Me Hg含量平均值分别为3.73(稻田)、2.47(旱田)、6.40μg/kg(菜地);路腊村汞矿区Me Hg含量平均值分别为1.92(稻田)、0.87(旱田)、2.47μg/kg(菜地)。以上结果说明万山废弃汞矿区的污染程度高于云场萍废弃汞矿区及路腊村废弃汞矿区。     

Historical record of effects of human activities on absolute and relative concentrations of Polycyclic aromatic hydrocarbons (PAHs) in Lake Chao, China

正Polycyclic aromatic hydrocarbons(PAHs)are attracting concern because of their potential toxicity,posing serious threats to health of humans and ecosystems(Kim et al.,2013;Zhao et al.,2016).Generally,similar to other contaminants'behaviors(Wu et al.,2001;Zhang et al.,2007,2008;Lu et al.,2009),PAHs result from natural organic matter and activities of humans,the latter's contribution usually outweighing the inputs from other sources(Fernández et al.,2000;Srogi,2007).     

电晕法处理挥发性有机化合物技术研究现状

本文介绍了挥发性有机物(VOCs)的特点及危害，综述了各种处理技术的基本原理、优势及存在的问题，并进行对比。重点介绍了电晕放电技术的原理以及研究现状，强调其相对于其他技术所独有的优越性，针对其存在的问题，预期了研究工作未来的发展方向。     

河岸材料对河流有机污染物降解能力的影响

研究了干砌石、浆砌石、蜂巢格宾和生态砖等河岸材料对河流有机污染物降解能力的影响.4种材料中,以生态砖为河岸的河流中总有机碳(TOC)沿程降解率分别是蜂巢格宾和浆砌石的6.14和3.15倍(p<0.05);生态砖、干砌石和蜂巢格宾河段中溶解性有机碳(DOC)沿程降解率分别是浆砌石的10.68、6.60和6.08倍(p<0...     

有机废水的电催化法降解研究现状

阐释了有机废水电催化法降解机理;综述了传统二维电极、新型三维电极电催化降解有机废水的原理及其应用现状,PbO2电极在三维电极处理有机废水中的应用现状、反应机理以及改性PbO2电极的研究进展;最后对未来发展方向进行了展望。     

Transition to large-scale organic vegetable production in the Salinas Valley, California

Studying the management strategies suited to large-scale organic production, particularly during the mandated 3-year transition period from conventional management, is a unique research challenge. Organic production traditionally relies on small, diverse plantings and complex management responses to cope with soil fertility and pest pressures, so research should represent decision-making options of an organic grower at the farm scale. This study analyzes crop, soil, pest and management changes during the organic transition period on two ranches (40 and 47 ha) in the Salinas Valley, California in cooperation with a large conventional vegetable producer, Tanimura and Antle, Inc. Permanent transects were established across the two ranches at the onset of adoption of organic practices, and soil and plants were sampled at harvest of almost all crops, while all management operations were recorded by the co-operator. The 10 ha blocks were divided into many small plantings, and 17 different cash crop and cover crop species were planted during the transition period. Management inputs consisted of a range of organic fertilizers and amendments, sprinkler and drip irrigation, cultivation and hand-hoeing, and several types of organic pesticides. Results from the 3-year period followed these general trends: increase in soil biological indicators (microbial biomass and arbuscular mycorrhizae), low soil nitrate pools, adequate crop nutrients, minor disease and weed problems, and sporadic mild insect damage. Multivariate statistical analyses indicated that some crops and cultivars consistently produced higher yields than others, relative to the maximum yield for a given crop. Multi-factor contingency tables showed clear differences in insect and disease damage between crop taxa. Although Tanimura and Antle, Inc. used some of the principles of organic farming (e.g., crop diversity, crop rotation, and organic matter (OM) management), they also relied on substitution-based management, such as fertigation with soluble nutrients, initially heavy applications of organic pesticides, and use of inputs derived from off-farm sources. Their initial production of a large number of crop taxa in small plantings at staggered intervals proved to be an effective strategy for avoiding risks from low yields or crop failure and allowed them to move towards a smaller number of select, successful crops towards the end of the transition. This study demonstrates the feasibility of large-scale producers to transition to organic practices in a manner that was conducive to both production goals and environmental quality, i.e., increased soil C pools, low soil nitrate, and absence of synthetic pesticides.     

三江平原湿地土壤活性有机碳组分特征及其与土壤酶活性的关系

对三江平原3种主要类型天然湿地(毛苔草湿地、小叶章湿地、岛状林湿地)O-20cm土壤活性有机碳(土壤微生物量碳、土壤可溶性有机碳)特征进行了研究,分析了不同湿地的土壤活性有机碳与土壤总有机碳及酶活性间的关系.结果表明:不同类型湿地的土壤活性有机碳组分含量存在较大的差异,土壤活性有机碳、土壤总有机碳及土壤脲酶、蔗糖酶、淀粉酶、过氧化氢酶的变化趋势具有基本近似的特征.表现为毛苔草湿地>小叶章湿地>岛状林湿地;土壤微生物量碳、可溶性有机碳与土壤总有机碳和酶活性存在显著正相关关系,其中,酶活性与土壤微生物量碳相关性最为显著.另外.毛苔草湿地土壤MBC/SOC、DOC/SOC的比值低于其它2种类型湿地,表明毛苔草湿地生物活性有机碳库的周转速率低.淹水抑制了微生物和酶的分解作用,有利于土壤有机碳的累积.因此,沼泽湿地水文条件的变化将会对土壤碳累积与分解过程产生较大的影响.     

有机改性膨润土吸附锌离子的性能

研究了有机改性膨润土对锌离子的吸附性能。结果表明:有机改性膨润土对水中锌离子的吸附在60 min达到平衡;在50 mL1、0 mg/L的锌离子溶液中,当其用量为1.0 g时,有机改性膨润土对水中锌离子的吸附去除率达到92.8%;温度对水溶液中锌离子的去除有一定的影响,有机改性膨润土吸附水中锌离子的过程为放热反应。平衡吸附量与平衡质量浓度之间的关系符合Freundlich和Langmuir等温吸附方程所描述的规律。     

白酒糟防除水田杂草试验初探

采用田间试验的方法,研究了白酒糟防除水田杂草的效果。结果表明:白酒糟对稗草、扁杆藨草、狼把草、蒲草均有不同程度的防效,水稻产量、经济效益均比对照(人工除草)高。