基于工艺过程的金属包装业VOCs污染特征

识别金属包装业挥发性有机化合物(volatile organic compounds,VOCs)产生和排放节点,定量分析不同类型生产工艺所排放VOCs的物种及含量,结合最大增量反应活性法和修正的气溶胶生成系数法对行业二次污染进行核算.结果表明,金属包装业排放的VOCs主要为苯系物、醇类、酮类和酯类,苯系物和醇类在不同类型工序和排污节点中贡献较大,酮类和酯类贡献相对较少,单物种浓度最高的VOCs为正丁醇,浓度达269.08mg·m~(-3);生产线与相应的排气筒之间VOCs物种浓度相关性较好,但物种种类存在差异;行业的O_3和二次有机气溶胶(secondary organic aerosol, SOA)生成潜势(以O_3/VOCs和SOA/VOCs计)分别为(3.09±0.94)g·g~(-1)和(2.58±1.99)g·g~(-1),苯系物和内全涂烘干工序为O_3和SOA的主要前体物和首要生成节点.     

污水处理厂中微塑料的去除效能与全流程分析——以北京某下沉式三级污水处理厂为例

污水处理厂排放是微塑料进入自然环境的重要途径之一,本研究对北京某下沉式三级污水处理厂八个工艺单元中微塑料的赋存特征和去除效能进行全流程分析.研究表明该厂赋存微塑料主要形态为纤维,主要成分为聚丙烯、聚酯和聚乙烯,尺寸≤500μm的微塑料影响最为显著.该厂对微塑料的整体去除率为91.7%,主要依靠沉淀和截留过滤去除.双层平流沉淀池（二沉池）的去除效能最高,而生化处理单元没有明显去除效果.整体上,微塑料呈现从污水向污泥迁移的趋势.该厂最终出水中微塑料浓度为1.3n/L,成分为聚酯纤维,出水排放没有引起周边受纳水体中微塑料浓度升高,但干扰了下游地表水体中微塑料的成分,深度处理单元是降低受纳水体微塑料污染风险的重要保障.     

基于能值理论武陵山片区旅游生态化水平测度与空间异质性分析

旅游生态化是实现旅游可持续发展的重要途径,而旅游生态化水平测度是旅游生态化研究的基础工作。本文创新性地构建了基于能值理论的旅游地生态化水平分析框架及测度模型。以武陵山片区为研究对象,基于研究区域2018年相关截面数据,以县级行政单位为研究单元对旅游生态化水平进行测度。测度结果表明：武陵山片区旅游生态化水平为中等偏下水平;县域单元等级数量呈“金字塔”形分布;评价体系目标层指标存在显著性差异。探索性空间数据分析方法分析表明研究区域旅游生态化水平空间分布上显示较为明显的集聚特征,显示较强的正相关,异质性弱。分指标空间分布显示大多数县域单元旅游社会经济的发展与环境保护不同步。     

Affordable CO2 negative emission through hydrogen from biomass,ocean liming,and CO2 storage

Mitigation and Adaptation Strategies for Global Change - A new process to remove carbon dioxide (CO2) from the atmosphere, by combining commercial industrial technologies with ocean liming and CO2...     

安徽省城市地表灰尘重金属污染及人体健康风险评价

本研究收集了安徽省合肥、蚌埠、芜湖、淮南、安庆、铜陵和宿州7个城市地表灰尘重金属含量的数据,分别采用地累积指数法、美国环境保护署(USEPA)人体健康风险评价法对地表灰尘重金属污染程度和人体健康风险水平进行评价。结果表明,所研究的安徽省7个城市地表灰尘中Pb、Cd、Cr、Zn和Cu平均含量分别为123.73±81.70、5.34±6.54、96.40±37.36、941.03±1 007.39和269.77±441.59 mg/kg,均高于安徽省土壤环境背景值。地累积指数法评价结果显示,安徽省城市地表灰尘Cr为轻度污染, Pb为中度污染,Zn为重度污染,Cd和Cu为严重污染。人体健康风险评价结果表明,安徽省城市地表灰尘重金属对儿童存在着明显的非致癌健康风险,对成人产生的非致癌健康风险不明显。重金属Cd和Cr致癌风险在安全范围内,不会对人群产生明显的致癌效应。手-口摄入是人体暴露于地表灰尘产生健康风险的主要途径,在同一暴露途径下儿童所遭遇的健康风险高于成人,儿童更容易受到地表灰尘中污染物的危害。     

辽河流域非点源污染空间特征遥感解析

应用遥感技术研究了辽河流域非点源污染发生特征.将环境卫星遥感数据耦合非点源(non-point Source,NPS)污染负荷估算模型,探索基于遥感像元尺度的非点源污染估算方法,目的是分析2010年辽河流域非点源污染特征,从而明确非点源污染的重点防治区和防治措施,为辽河流域水环境污染防治提供技术支持.结果表明,2010年辽河流域总氮排放量为10.3万t,总磷排放量为0.68万t,化学需氧量排放量为13.1万t,氨氮排放量为1.8万t;目前,对于辽河流域主要的非点源污染类型为农业面源;2010年辽河流域面源污染对水质污染的贡献率表现为总氮67.4%,总磷76.4%,化学需氧量39.4%和氨氮21.9%;空间分布上辽河流域的南部是污染最严重的地区,其次是东北部.本研究结合遥感技术发展了以遥感像元为基本模拟单位的非点源污染负荷估算方法,明确了2010年辽河流域的非点源污染产生量和空间分布特征,为辽河流域污染治理防治工作提供了理论依据.     

Investigation of potential interferences on the measurement of dissolved reactive phosphate using zirconium oxide-based DGT technique

A diffusive gradients in thin films (DGT) technique based on hydrous zirconium oxide (Zr-oxide) has been recently developed for the measurement of dissolved reactive phosphate (DRP). In this study, the detailed performance of the DGT technique is reported. Spiking experiments revealed that several orthophosphate monoester compounds contributed to the Zr-oxide DGT measurements of DRP. However, such a phenomenon is unlikely to occur during field conditions due to the low concentration of organic P in typical natural waters. The presence of Cl- (up to 106 g/L), SO42- (up to 16 g/L), HCO3- (up to 817 g/L), and AsO2- and AsO 3 4 (both up to 1 mg As/L) in solutions had negligible effects on the measurement of DRP. The threshold concentrations of Cl-, SO42- and HCO3- have been increased from previous reports for the measurements of DRP using other adsorbent-based DGT techniques. The capacity for DGT measurements of DRP decreased with increasing solution pH (4.2-9.2). The lowest capacity (95 μg P/m2 at pH 9.2) was still greater than that of other DGT techniques that are usually used for the measurement of DRP (2-12 μg P/cm2 ). The Zr-oxide binding gel could be stored for up to 2 years without any aging effect. This period of validity was considerably longer than the ferrihydrite binding gel that is commonly used in present DGT devices (6 months). The field application revealed that the concentrations of DRP measured in three fresh water samples using the Zr-oxide DGT technique were in agreement with those of the traditional colorimetric method.     

一体化生物膜工艺处理滨海农村污水脱氮特性研究

通过模拟农村生活污水水质和间歇进水特点,考察一体化生物膜工艺对农村生活污水的脱氮能力。该工艺水解酸化池和局部循环曝气池有效容积比为13∶10,曝气装置位于局部循环曝气池中间底部,出水端设置斜管沉淀池,兼有泥水循环功能。装置连续运行30周,平均进水量为300 L/d,生物反应区HRT为4 d。研究结果表明:在出水BOD5平均质量浓度为15.5 mg/L时,出水TN、NH3-N、NO-3-N的平均质量浓度控制在16.9,3.53,13.2 mg/L以下,出水碳、氮指标均达到GB 18918—2002《城镇污水处理厂污染物排放标准》中一级排放要求。该工艺对间歇排放的农村生活污水具有较好的硝化能力,出水NO-3-N占TN含量的78.1%,而反硝化作用在一定程度上受到制约。     

Removal of Pb(II) from aqueous solution by hydrous manganese dioxide: Adsorption behavior and mechanism

Hydrous manganese dioxide (HMO) synthesized by redox of potassium permanganate and hydrogen peroxide was used as an adsorbent for Pb(Ⅱ) removal.The specific surface area,pore volume and BJH pore diameter of the HMO were 79.31m2/g,0.07cm3/g and 3.38 nm,respectively.The adsorption equilibrium at 298K could be well described by the Langmuir isotherm equation with q max value of 352.55mg/g.The negative values of G and the positive values of H and S indicated the adsorption process was spontaneous and endothermic.The pseudo second-order equation could best fit the adsorption data.The value of the calculated activation energy for Pb(Ⅱ) adsorption onto the HMO was 38.23 kJ/mol.The uptake of Pb(Ⅱ) by HMO was correlated with increasing surface hydroxyl group content and the main adsorbed speciation was PbOH+.The final chemical state of Pb(Ⅱ) on the surface of HMO was similar to PbO.HMO was a promising candidate for Pb(Ⅱ) removal from aqueous solution.     

Profile of the culturable microbiome capable of producing acyl-homoserine lactone in the tobacco phyllosphere

Bacterial populations coexisting in the phyllosphere niche have important effects on plant health. Quorum sensing (QS) allows bacteria to communicate via diffusible signal molecules, but QS-dependent behaviors in phyllosphere bacterial populations are poorly understood. We investigate the dense and diverse N-acyl-homoserine lactone (AHL)-producing phyllosphere bacteria living on tobacco leaf surfaces via a culture-dependent method and 16S rRNA gene sequencing. Our results indicated that approximately 7.9%-11.7% of the culturable leaf-associated bacteria have the ability to produce AHL based on the assays using whole-cell biosensors. Sequencing of the 16S rRNA gene assigned the AHL-producing strains to two phylogenetic groups, with Gammaproteobacteria (93%) as the predominant group, followed by Alphaproteobacteria. All of the AHL-producing Alphaproteobacteria were affiliated with the genus Rhizobium, whereas the AHL-producing bacteria belonging to the Gammaproteobacteria mainly fell within the genera Pseudomonas, Acinetobacter, Citrobacter, Enterobacter, Pantoea and Serratia. The bioassays of supernatant extracts revealed that a portion of the strains have a remarkable AHL profile for AHL induction activity using the two different biosensors, and one compound in the active extract of a representative isolate, NTL223, corresponded to 3-oxo-hexanoyl-homoserine lactone. A large population size and diversity of bacteria capable of AHL-driven QS were found to cohabit on leaves, implying that cross-communication based AHL-type QS may be common in the phyllosphere. Furthermore, this study provides a general snapshot of a potential valuable application of AHL-producing bacteria inhabiting leaves for their presumable ecological roles in the phyllosphere.