长江三角洲水田保护性耕作制度的碳收集效应估算

耕作制度对农田土壤有机碳的稳定和积累作用显著,探讨耕作制度演变下农田土壤碳库动态,将有助于农田土壤碳收集的技术选择及政策制定。利用已发表的田间定位试验数据,构建不同耕作制度下长江三角洲水田耕层土壤有机碳密度的估算模型。依据该区近20多年来耕作制度演变动态,对保护性耕作制度的土壤碳收集效应进行了初步估算。结果表明,油菜面积的扩大、小麦的少免耕和作物秸秆的还田分别约增加土壤耕层有机碳0.94 Tg、2.76 Tg和3.95 Tg,其中以麦稻复种转向油稻复种的单位面积碳收集效应为最高。最后,就碳收集效应估算的方法进行了相关讨论,并就土壤碳收集研究和如何提高土壤碳收集潜力提出了一些建议。     

Primary and secondary organic aerosol in an urban/industrial site: Sources, health implications and the role of plastic enriched waste burning

PM10 samples were collected from an urban/industrial site nearby Athens, where uncontrolled burning activities occur. PAHs, monocarboxylic, dicarboxylic, hydroxycarboxylic and aromatic acids, tracers from BVOC oxidation, biomass burning tracers and bisphenol A were determined. PAH, monocarboxylic acids, biomass burning tracers and bisphenol A were increased during autumn/winter, while BSOA tracers, dicarboxylic- and hydroxycarboxylic acids during summer. Regarding aromatic acids, different sources and formation mechanisms were indicated as benzoic, phthalic and trimellitic acids were peaked during summer whereas p-toluic, isophthalic and terephthalic were more abundant during autumn/winter. The Benzo[a]pyrene-equivalent carcinogenic power, carcinogenic and mutagenic activities were calculated showing significant (p < 0.05) increases during the colder months. Palmitic, succinic and malic acids were the most abundant monocarboxylic, dicarboxylic and hydrocarboxylic acids during the entire sampling period. Isoprene oxidation was the most significant contributor to BSOA as the isoprene-SOA compounds were two times more abundant than the pinene-SOA (13.4 ± 12.3 and 6.1 ± 2.9 ng/m³, respectively). Ozone has significant impact on the formation of many studied compounds showing significant correlations with: isoprene-SOA (r = 0.77), hydrocarboxylic acids (r = 0.69), pinene-SOA (r = 0.63),dicarboxylic acids (r = 0.58), and the sum of phthalic, benzoic and trimellitic acids (r = 0.44). PCA demonstrated five factors that could explain sources including plastic enriched waste burning (30.8%), oxidation of unsaturated fatty acids (23.0%), vehicle missions and cooking (9.2%), biomass burning (7.7%) and oxidation of VOCs (5.8%). The results highlight the significant contribution of plastic waste uncontrolled burning to the overall air quality degradation.     

不同施肥措施对水稻土壤微生物镉抗性的影响

镉（Cd）是最常见的土壤重金属污染物之一,对植物和人体具有毒害作用,研究不同施肥条件下的土壤微生物Cd抗性水平,可以为有机肥改良重金属污染提供一定的理论依据.为了探讨施无机肥和有机肥对于微生物Cd抗性水平的影响,在中国江苏常州、江西上高和福建福州水稻种植区采集了施有机肥（猪粪）和无机肥的土壤样品及猪粪样品,利用功能基因芯片（GeoChip 5.0）技术,研究了土壤微生物Cd抗性功能基因的响应及影响Cd抗性功能微生物群落互作的因素.结果表明,施有机肥土壤中有效态Cd含量[（1.08±0.70）mg·kg^-1]显著低于施无机肥土壤[（3.75±1.22）mg·kg^-1]（P<0.05）.土壤及猪粪样品中共检测到639个Cd抗性功能基因,施有机肥土壤中微生物Cd抗性基因丰度高于施无机肥土壤;有效态Cd含量、含水率、pH和铵态氮含量是影响Cd抗性微生物分布的重要环境因素.对Cd抗性微生物分子生态网络分析表明,施无机肥条件下,pH、含水率和有效态Cd含量是影响功能微生物潜在互作关系的主要因素;施有机肥条件下,主要影响因素是全钾和含水率.相比较无机肥,施用有机肥提高了土壤中微生物的Cd抗性水平及耐Cd微生物分子生态网络中的正相互作用.     

光谱特征法辨识不同污染景观河道中溶解性有机物的组分与来源

利用三维荧光光谱(EEMs)结合平行因子分析方法(PARAFAC)及紫外-可见光谱技术(UV-vis),对苏州古城区内不同污染状况的景观河道中溶解性有机物(DOM)的光谱特征和来源进行解析.结果表明,苏州古城区内景观河道水体总体上表现为氮、磷营养盐污染.水体中的DOM解析出4种荧光组分,分别为自源类色氨酸C1(AEx/...     

汽油车技术发展对尾气排放影响研究进展

近年来,汽油车尾气排放已成为城市大气污染的主要来源之一.为减少油耗、温室气体和大气污染物的排放,汽油直喷技术(GDI)、醇类燃料替代以及混合动力系统等新兴技术被应用到汽车产品中,该研究对GDI发动机汽车、醇类燃料车和混合动力车的颗粒物(PM)、氮氧化物(NO_x)、总碳氢化合物(THC)的排放研究进行梳理和总结,综合评估先进动力技术和醇类燃料的环境影响.结果表明:GDI汽油车的PM排放因子为进气道喷射(PFI)汽油车的1.2~5倍,加装汽油颗粒物捕集器(GPF)后GDI汽油车的PM排放大幅下降,同时具备催化能力的GPF可减少NO_x和THC排放.与汽油车相比,乙醇燃料车PM排放量减少了35%~56%,尾气THC排放减少了10%~44%,但挥发性有机物(VOCs)蒸发排放增加了20%~41%,其主要来自于日呼吸损失.各类型车辆的NO_x排放差异较小,比较结果存在一定的不确定性.混合动力车相比传统内燃机汽车污染物减排优势明显,可积极推广其在公共交通和私家车队中的应用.建议今后研究应着重关注以下几个方面:①GDI和混合动力车在实际条件下排放污染物的环境影响;②醇类燃料车VOCs蒸发排放控制技术及相关法规标准的完善;③新兴技术汽油车排放污染物的生成机理及其影响因素.      

Effects of reductive inorganics and NOM on the formation of chlorite in the chlorine dioxide disinfection of drinking water

Chlorine dioxide (ClO₂) disinfection usually does not produce halogenated disinfection by-products, but the formation of the inorganic by-product chlorite (ClO₂^–) is a serious consideration. In this study, the ClO₂^– formation rule in the ClO₂ disinfection of drinking water was investigated in the presence of three representative reductive inorganics and four natural organic matters (NOMs), respectively. Fe²⁺ and S^2– mainly reduced ClO₂ to ClO₂^– at low concentrations. When ClO₂ was consumed, the ClO₂^– would be further reduced by Fe²⁺ and S^2–, leading to the decrease of ClO₂^–. The reaction efficiency of Mn²⁺ with ClO₂ was lower than that of Fe²⁺ and S^2–. It might be the case that MnO₂ generated by the reaction between Mn²⁺ and ClO₂ had adsorption and catalytic oxidation on Mn²⁺. However, Mn²⁺ would not reduce ClO₂^–. Among the four NOMs, humic acid and fulvic acid reacted with ClO₂ actively, followed by bovine serum albumin, while sodium alginate had almost no reaction with ClO₂. The maximum ClO₂^– yields of reductive inorganics (70%) was higher than that of NOM (around 60%). The lower the concentration of reductive substances, the more ClO₂^– could be produced by per unit concentration of reductive substances. The results of the actual water samples showed that both reductive inorganics and NOM played an important role in the formation of ClO₂^– in disinfection.     

Evaluating the e ects of granular and membrane filtrations on chlorine demand in drinking water

In this study, chlorine decay experiments were conducted for the raw water from Nakdong River that is treated by Chilseo Water Treatment Plant (CWTP) situated in Haman, Korea as well as the e uents from sand and granular activated carbon (GAC) filters of CWTP and fitted using a chlorine decay model. The model estimated the fast and slow reacting nitrogenous as well as organic/inorganic compounds that were present in the water. It was found that the chlorine demand due to fast and slow reacting (FRA and SRA) organic/inorganic substances was not reduced significantly by sand as well as GAC filters. However, the treated e uents from those filters contained FRA and SRA that are less reactive and had small reaction rate constants. For the e uents from microfiltration, ultrafiltration, and nanofiltration the chlorine demand because FRA and SRA were further reduced but the reaction rate constants were larger compared to those of sand and GAC filter e uents. This has implications in the formation of disinfection by products (DBPs). If DBPs are assumed to form due to the interactions between chlorine and SRA, then it is possible that the DBP formation potential in the e uents from membrane filtrations could be higher than that in the e uents from granular media filters.     

Biodegradability of soil water soluble organic carbon extracted from seven di erent soils

Water soluble organic carbon (WSOC) is considered the most mobile and reactive soil carbon source and its characterization is an important issue for soil ecology study. A biodegradability test was set up to study WSOC extracted from 7 soils di erently managed. WSOC was extracted from soil with water (soil/water ratio of 1:2, W/V) for 30 min, and then tested for biodegradability by a liquid state respirometric test. Result obtained confirmed the finding that WSOC biodegradability depended on the both land use and management practice. These results suggested the biodegradability test as suitable method to characterize WSOC, and provided useful information to soil fertility.     

饮用水中有机污染物的监测和评价方法

水质中毒性有机物是致癌的主要因素之一，饮用水的质量已引起人们高度重视，近代微量富集技术和色谱技术取得了举世瞩目的进展，卓有成效地分离，鉴定饮用水中痕量、复杂、多组分有机化合物，流行病学调查和污染毒理学研究的发展，建立了有机污染物危害人体健康和生态环境的定量关系，为采用多污染物评价方法评价水质奠定的基础。     

运河水中悬浮物和底泥上有机污染物的探查

利用ＧＣ／ＭＳ／ＤＳ系统和保留指数,对运河（常州段）悬浮物和底泥上的有机污染物进行了概要分析。结果显示,该段河流的悬浮物和底泥上含有直链烷烃、多环芳烃、直链醛酮、烷基磺酸、苯酯类、邻苯二甲酸酯类、硝基联苯、二苯砜、醇类、羧酸类等有机污染物和致癌物。河流悬浮物和底泥上所鉴定出的有机污染物数量相当,浓度范围基本一致。同一段面底泥上的浓度稍高于悬浮物上的浓度;枯水期悬浮物上的浓度稍高于丰水期悬浮物上浓度