2009—2017年南充市城区酸雨特征分析

为了更为有效地治理酸雨污染,根据南充市环境监测中心站提供的2009—2017年降水监测数据,对南充市城区酸雨污染情况进行了分析及源解析。结果表明:2009—2017年,南充市降水pH从4.60波动上升至5.6以上,酸雨频率波动下降,酸雨污染情况有所改善;[SO4^2-]/[NO3^-]从4.92下降至0.86,酸雨污染类型从硫酸型转变为硝酸-硫酸型。同时,对比分析2014—2016年大气污染物排放源可知,NOx排放源中,工业污染源占比由14%降至11%,生活污染源由2%上升至5%;SO2排放源中,工业污染源占比由62%降至43%,生活污染源由38%上升至57%,表明南充市SO2污染已从以工业污染源为主转变为工业污染源与生活污染源并重。     

临安大气本底站酸雨污染变化特征与影响因素分析

利用临安大气本底站酸雨观测数据,研究临安大气本底站降水pH,酸雨发生频率的时间分布特征、变化趋势及其影响因素;借助后向轨迹分析法分析输送形势对临安大气本底站酸雨的影响。研究表明:最近6年间临安大气本底站降水pH各月均值均小于4.5,均达到强酸雨的程度;临安大气本底站的酸雨发生频率表现为夏季低、秋季高;1985—2009年临安大气本底站降水的年均pH全部达到酸雨程度。根据Daniel趋势检验,临安大气本底站年均降水pH总体上呈逐年下降的趋势。风速越小,酸雨出现频率就越高;降水pH受降水量的影响较大。临安大气本底站的酸雨与降水前的大气中SO2浓度存在负相关的关系。根据气团的来向与酸雨污染程度的关系分析,临安大气本底站的酸雨污染受到其北部地区和浙西地区的酸雨气体物输送的影响较大。临安大气本底站的酸雨污染特征已由原来的硫酸型转为硫酸型与硝酸型并重。     

伊犁河谷大气酸沉降变化趋势

对2007—2014年伊犁河谷大气降水监测结果进行分析,结合伊犁河谷流域相对湿润、封闭的地形地貌和逆温气候资源特征与煤化工、煤电发展态势,类比预测了酸雨前体物的增加对伊犁河谷大气降水p H值变化趋势的影响。研究结果表明:目前伊犁河谷大气降水尚处于本底水平,城市人类活动对伊犁河谷大气降水酸雨前体物SO2、NOx的贡献高于郊区。伊犁河谷酸雨前体物SO2、NOx排放强度与大气降水硫酸盐和硝酸盐实际监测浓度相存在正相关性。类比同处于新疆干旱区乌鲁木齐市出现酸雨年度的情况,"十三五"期间,伊犁河谷大规模煤电、煤化工基地的建设,酸雨前体物排放量大幅增加,将会造成酸雨发生的风险。     

上海青浦地区大气降水的化学特征

利用上海青浦地区2003—2014年观测的大气降水监测资料,分析该区域12 a以来大气降水的酸化程度、化学组成特征,探讨降水中化学成分的不同来源及相对贡献。结果表明:降水pH年均值为4.43~6.33,酸雨频率为2.6%~86.8%,降水酸化程度大致经历了明显恶化和波动变化2个阶段。降水电导率年均值为1.77~4.01 m S/m,呈下降趋势。降水中各离子雨量加权平均当量浓度顺序为SO_4~(2-)NH_4~+Ca~(2+)NO_3~-Cl~-Na~+Mg~(2+)F-K~+,SO_4~(2-)、NH+4、Ca~(2+)和NO_3~-是降水中的主要离子,占离子总量的83.0%;降水类型由硫酸型向硫酸和硝酸混合型转变。降水离子中的二次组分SO_4~(2-)、NO_3~-和NH_4~+绝大部分来源于人为源,Ca~(2+)、Mg~(2+)和K+主要来自于土壤源和人为源的贡献,Cl~-主要来自海洋源,同时人为源的影响也不可忽视。     

2006-2020年上海市闵行区大气降水化学特征及来源分析

为研究上海市闵行区大气降水化学特征及来源,以2006—2020年上海市闵行区大气降水监测数据为依据,对大气降水量、pH值、电导率(EC)和主要离子进行了统计分析。结果表明:2006—2020年上海市闵行区大气降水呈酸性,pH值范围为4.41~5.19,酸雨频率呈下降趋势;EC变化范围为1.26~3.67 mS/m,平均值为2.32 mS/m;夏季pH值最高,酸雨发生频率、EC和总离子浓度最低,冬季pH值最低,总离子浓度最高。大气降水中各离子组分浓度占比大小排序为:SO^(2-)_(4)>NH^(+)4>NO^(-)3>Ca^(2+)>Cl^(-)>Na^(+)>Mg^(2+)>F^(-)>K^(+),主要阴、阳离子SO^(2-)_(4)、Ca^(2+)和NH^(+)4浓度呈明显下降趋势,NO^(-)3浓度变化较平稳;SO 2-4与NO^(-)3的浓度比范围为0.94~3.59,呈波动下降趋势,降雨类型由硫酸型逐步转为混合型。因子分析及相关性分析显示,因子1中所有的离子成分都有较大的载荷,各离子在来源上可能具有一定的共性,Ca^(2+)与Mg^(2+)、K^(+)表现出显著相关,其可能来源于地壳组分;Cl^(-)与K^(+)、Mg^(2+)、Ca^(2+)的相关性显著,Mg^(2+)、K^(+)与Cl^(-)、Na^(+)有强相关性,表明海洋输送及生物质燃烧对大气降水化学组成的影响;NO_(3)^(-)、SO^(2-)_(4)和NH^(+)4在因子2中为高荷载,且有很好的相关性,它们可能有相似的来源或形成化合物共同存在。     

博乐市降水酸度特征初探

根据博乐市2005—2010年降水数据,对酸雨发生的原因进行了分析。分析结果表明：博乐市地形适合水汽输入,存在远距离污染物跨境传输和产生连续大降雨的条件,使其境内产生酸雨的可能性加大;酸雨发生在冬季采暖期,且NO3^-浓度比未发生酸雨时略高;另外,博乐市属北方干旱区城市,土壤偏碱性,降水总体为偏弱碱性特点不变。除以上主...     

奎屯市大气降水现状分析及评价

为了解奎屯市大气降水状况及主要污染物,奎屯市监测站于2002年对大气降水进行了为期一年的酸雨监测。本文根据监测结果,介绍了奎屯市酸雨现状,对其成因进行了分析,并提出防治酸雨污染的可行性建议。     

燃煤工业城市大气细颗粒物中水溶性无机离子的季节变化特征及来源解析——以邯郸市为例

为探究典型燃煤工业城市邯郸市的大气细颗粒物(PM2.5)污染水平及水溶性无机离子特征,于2016年1—12月采集了当地大气PM2.5样品,然后利用离子色谱法测得水溶性无机离子的组分,分析了不同季节水溶性无机离子随PM2.5的浓度变化特征。通过对PM2.5中的阴离子、阳离子进行分析发现,SO4^2-、NO3^-和NH4^+在春夏秋冬四季均为PM2.5中的主要离子成分,SO4^2-、NO3^-和NH4^+的浓度之和在春夏秋冬四季占各季节总的水溶性无机离子浓度的百分比分别为84.6%、77.4%、89.9%、62.5%。其中,在春季和冬季含量最高的3种离子分别是NO3^-、SO4^2-和NH4^+,夏季含量最高的3种离子分别是SO4^2-、NH4^+和NO3^-,而秋季含量最高的3种离子分别是NH4^+、SO4^2-和NO3^-。相关性分析发现,2016年春季、夏季和秋季PM2.5为酸性,冬季为碱性。SO4^2-、NO3^-、NH4^+浓度分析表明,冬季PM2.5中的一次建筑扬尘排放较多。通过主成分分析法得出,PM2.5中水溶性无机离子主要来源于二次转化和生物质燃烧。     

西安市大气颗粒物PM2.5与降水关系的探讨

对西安市2011年的降水及PM_2.5进行采样，并对其进行了pH及无机水溶性离子测定。结果表明，西安市酸雨的污染类型以硫酸型污染为主，连续性降水对大气颗粒物的去除效果明显，pH随降水量的增加而减小。对采样日降水前和降水后3 h的PM_2.5监测结果表明降水对PM_2.5质量浓度与其中的离子有一定去除作用。西安市的PM_2.5呈酸性，并且与降水的pH有着很好的相关性；另外降水前PM_2.5的质量浓度、SO₄^2-浓度与降水pH呈负相关，NO₃^-与降水pH的相关性不明显。近几年PM_2.5和降水中的SO₄^2-/NO₃^-当量值变化趋势表明西安市大气污染已步入煤烟和机动车尾气混合型污染类型，且机动车污染对大气污染和酸雨的贡献比例有所增加。     

连云港市酸雨污染特征分析及控制

根据连云港市降水监测资料和有关环境资料，分析了该市酸雨的时空分布特征、降水酸度和酸雨频率的年变化情况，以及酸雨发展趋势，结果表明，该市酸雨污染冬季比夏季严重，主要集中在西部地区，SO2是影响降水酸度的主要因素，酸雨类型以硫酸型为主。指出近年来该市酸雨污染趋势缓和，但随着经济发展，SO2的排放量加大，酸雨污染有扩大趋势，必须采取果断措施予以控制。     

Study on Size Distribution of Total Aerosol and Water-Soluble Ions During an Asian Dust Storm Event at Jeju Island, Korea

Soil dust particles transported from loess regions of the Asian continent, called Asian dust, highly influences the air quality of north-eastern Asia and the northern Pacific Ocean. In order to investigate the effects of these dust storms on the chemical composition of atmospheric aerosol particles with different size, measurements of size distributions of total aerosol and major ion species were carried out on Jeju Island, Korea during April 2001. Juju Island was chosen for the study because the levels of emissions of anthropogenic air pollutants are very low. A 5-stage cascade impactor was used to sample size-fractionated aerosol particles. Samples were analyzed for major water-soluble ions using Dionex DX-120 ion chromatograph. The average mass concentration of total aerosol was found to be 24.4 and 108.3 microg m(-3) for non-Asian dust and Asian dust periods, respectively. The total aerosol size distribution, measured during the non-Asian dust period, was bimodal, whereas the coarse particles dominated the size distribution of total aerosol during the Asian dust period. It was found that SO4(2-), NH4+ and K+ were mainly distributed in fine particles, while Cl-, NO3-, Na+, Mg2+ and Ca2+ were in coarse particles. Although SO4(2-) was mainly distributed in fine particles, during the Asian dust period, the concentrations in coarse particles were significantly increased. This indicates heterogeneous oxidation of SO2 on wet surfaces of basic soil dust particles. The NH4+ was found to exist as (NH4)2SO4 in fine particles, with a molar ratio of NH4+ to SO4(2-) of 2.37 and 1.52 for non-Asian dust and Asian dust periods, respectively. Taking into account the proximity of the sampling site to the sea, and the observed chloride depletion, coarse mode nitrate, during the non-Asian dust period, is assumed to originate from the reaction of nitric acid with sodium chloride on the surfaces of sea-salt particles although the chloride depletion was not shown to be large enough to prove this assumption. During the Asian dust period, however, chloride depletion was much smaller, indicating coarse nitrate particles were mainly produced by the reaction of nitric acid with surfaces of basic soil particles. Most chloride and sodium components were shown to originate from sea-salt particles. Asian dust aerosols, arriving at Jeju Island, contained considerable amounts of sea-salt particles as they passed over the Yellow Sea. Ca2+ was shown to be the most abundant species in Asian dust particles.     

广州市白云山降水的化学特征及源解析

以2006年广州市白云山降水监测资料为基础，对其降水样品的化学特征进行了分析。结果表明，白云山降水样品pH值分布为3.04—6.41，雨量加权pH平均值为4.26，酸雨频率为70.2％，降水中的主要阳离子是Ca^2＋和NH^＋4分别占阳离子总量的46.4％和17.5％；主要阴离子为SO^2-4和NO^-3，分别占阴离子总量的59.0％和19.9％。相对酸度（FA）和中和因子（NF）计算结果表明，约有84.7％的降水酸度被碱性成分Ca^2＋和NH^＋4中和。利用富集系数方法，计算结果表明SO^2-4和NO^-3主要来源于人类活动，而Ca^2＋和K^＋主要来源于岩石／土壤风化。     

Welding fumes from stainless steel gas metal arc processes contain multiple manganese chemical species

Fumes from a group of gas metal arc welding (GMAW) processes used on stainless steel were generated using three different metal transfer modes and four different shield gases. The objective was to identify and measure manganese (Mn) species in the fumes, and identify processes that are minimal generators of Mn species. The robotic welding system was operated in short-circuit (SC) mode (Ar/CO2 and He/Ar), axial spray (AXS) mode (Ar/O2 and Ar/CO2), and pulsed axial-spray (PAXS) mode (Ar/O2). The fumes were analyzed for Mn by a sequential extraction process followed by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) analysis, and by X-ray diffraction (XRD). Total elemental Mn, iron (Fe), chromium (Cr) and nickel (Ni) were separately measured after aqua regia digestion and ICP-AES analysis. Soluble Mn2+, Fe2+, Fe3+, and Ni2+ in a simple biological buffer (phosphate-buffered saline) were determined at pH 7.2 and 5.0 after 2 h incubation at 37 C by ion chromatography. Results indicate that Mn was present in soluble form, acid-soluble form, and acid-soluble form after reduction by hydroxylamine, which represents soluble Mn0 and Mn2+ compounds, other Mn2+ compounds, and (Mn3+ and Mn4+) compounds, respectively. The dominant fraction was the acid-soluble Mn2+ fraction, but results varied with the process and shield gas. Soluble Mn mass percent in the fume ranged from 0.2 to 0.9%, acid-soluble Mn2+ compounds ranged from 2.6 to 9.3%, and acid plus reducing agent-soluble (Mn3+ and Mn4+) compounds ranged from 0.6 to 5.1%. Total Mn composition ranged from 7 to 15%. XRD results showed fumes had a crystalline content of 90-99% Fe3O4, and showed evidence of multiple Mn oxides, but overlaps and weak signals limited identification. Small amounts of the Mn2+ in the fume (<0.01 to ≈ 1% or <0.1 to ≈ 10 microg ml(-1)) and Ni2+ (<0.01 to ≈ 0.2% or <0.1 to ≈ 2 mg ml(-1)) ions were found in biological buffer media, but amounts were highly dependent on pH and the welding process. Mn generation rates for the fractions were tabulated, and the influence of ozone is discussed. The conclusions are that exposures to welding fumes include multiple Mn species, both soluble and insoluble, and that exposures to Mn species vary with specific processes and shield gases.     

Observations on the measurement of total antimony and antimony species in algae, plant and animal tissues

This paper describes our experiences with undertaking measurements of total antimony and antimony speciation in algae, plant and animal tissues. Digestion with nitric acid alone is suitable to release antimony from animal tissues. When organisms have high silica contents, e.g. some plants and algae, the addition of tetrafluorboric acid is required to dissolve silica as some antimony is retained by silica in extracts. Antimony in digested extracts is present as Sb5+ and hydride generation procedures can be used to determine total antimony concentrations, as total antimony in extracts will not be under estimated. Relatively non-aggressive solvents such as water, dilute nitric acid, sodium hydroxide and enzymes remove highly variable amounts of antimony (2-84%) from algae, plant and animal tissues. Addition of Sb3+ and Sb5+ to NIST CRM 1572 Citrus Leaves, pre- and post-extraction with water showed that Sb3+ is oxidised to Sb5+ while Sb5+ is redistributed amongst binding sites giving rise to artefacts. DOLT-2 and algae extracts indicated the presence of only inorganic antimony. A moss sample had inorganic antimony and a number of unknown antimony species in extracts. Future studies should explore the nature of the binding of antimony in tissues as solvents commonly used to extract metals and metalloids from algae, plant and animal tissues are not appropriate.     

乌鲁木齐市可吸入颗粒物水溶性离子特征及来源解析

采暖期时在乌鲁木齐市采集了环境空气中的可吸入颗粒物,对可吸入颗粒物质量浓度及8种水溶性离子的特征和来源进行了分析。结果表明,细粒子和粗粒子的月平均质量浓度分别是53.5～233.3μg/m3和38.9～60.9μg/m3;细粒子和粗粒子中水溶性离子主要由SO24-、NH4+和NO3-组成;粗粒子中NH4+与NO3-和SO24-的相关性分别是0.70和0.66,细粒子中NH4+与NO3-和SO24-的相关性分别是0.89和0.93,铵盐是乌鲁木齐可吸入颗粒物主要存在形式;煤烟尘是乌鲁木齐市采暖期可吸入颗粒物的主要来源。     

乌鲁木齐市降水酸度及化学特征的初步研究

降水酸度和离子平衡研究结果表明,乌鲁木齐市降水为非酸性雨,但其PH值有较明显的季节变化,降水中的SO_4~(2-)、Ca~(2+)、和NH_4~+是影响酸度的关键离子,与其他地区相比,乌鲁木齐市降水中的Ca~(2+)浓度是酸雨区(贵阳、重庆)平均值的3.50倍,是非酸雨区(北京、天津)平均值的1.86倍。可见,乌鲁木齐市降水酸度的高低,不仅取决于酸性离子浓度,而且更重要的是取决于碱性离子浓度。     

Chemical speciation of inorganic pollutants in river–estuary–sea water systems

Monitoring studies and thermodynamic modeling were used to reveal the changes of inorganic chemical species of some water pollutants (nutrients and trace metals such as Fe, Mn, Zn, Cu, Cd and Pb) inthe river-estuary-sea water system. The case studies were two rivers, Kamchiya and Ropotamo, representing part of the Bulgarian Black Sea water catchment area, and having different flow characteristics. There were no major differences in inorganic chemical species of the two river systems. NO3(-) and NO2(-) chemical species showed no changes along the river-estuary-sea water system. Concerning phosphates six different species were calculated and differences between the three parts of the systems were established. The HPO4(2-) and H2PO4(-) species were found to be dominant in river waters. The H2PO4(-) species quickly decreased at the expense of HPO4(2-) and Ca, Mg and Na phosphate complexes in estuary and seawater. Trace metals showed a great variety of chemical species. Fe(OH)2(+) species prevailed in river waters, and Fe(OH)3(0) species--in sea waters. Me2+ and MeCO3(0) (Me = Cu, Pb) and PbHCO3(+) were dominant in river waters, while Cu(CO3)2(2-) and PbCl(-) species appear also in sea waters. Cd2+ species prevailed in river and estuary waters, and CdCln(2-n) (n = 1-3) species, in seawater. Free Zn2+ species predominated in all systems but downstream their percentage decreased at the expense of Zn phosphates, carbonates,sulfates and chlorides complexes. Only free Mn2+ species were dominant along the systems.     

Atmospheric wet deposition of soluble macro-nutrients in the Cilician Basin, north-eastern Mediterranean sea

In order to estimate wet deposition atmospheric fluxes of macro-nutrients into the eastern Mediterranean coastal waters, soluble inorganic phosphate (PO4(3-)), nitrate (NO3-) and nitrite (NO2-) concentrations in precipitation (from February 1996 to June 1997) have been measured at a coastal sampling site, Erdemli, Turkey. Water-soluble inorganic PO4(3)-P, a reactive, bioavailable, limiting macro-nutrient in the oligotrophic waters of the eastern Mediterranean was studied with respect to its contribution to biological productivity. Reactive PO4(3-)-P and NO2(-) + NO3(-)-N concentrations were found to be highly variable in rainwater samples. One of the aims of the study was to determine the contribution of dust transport to the soluble macro-nutrient budget of the eastern Mediterranean. No differences were found between the mean reactive P and NO(2-) + NO3(-)-N concentrations of "red rain" and normal rain events. Most likely as a result of low solubility of crustal phosphorus, dust episodes were not found to be important sources of reactive P, in terms of wet deposition. The annual wet deposition fluxes of reactive PO4(3-)-P and NO2(-) + NO3(-)-N into the Cilician Basin were respectively estimated to be 0.010 g P m(-2) per year and 0.23 g N m(-2) per year, which are comparable to the fluxes from land-based sources in the north-eastern Mediterranean. The incorporation of water soluble bioavailable PO4(3-)-P and NO2(-) + NO3(-)-N delivered via atmospheric wet deposition could be responsible for approximately 3.3% (0.40 g C m(-2) per year) and 11.0% (1.31 g C m(-2) per year) respectively, of the mean annual new production in the north-eastern Mediterranean.     

神经网络用于光度法同时测定多种重金属离子

采用可见分光光度法,通过构筑16-5-4多目标神经网络模型实现同时测定溶液中Cd2+、Pb2+、Cu2+、As3+的含量。实验以4-(2-吡啶偶氮)-间苯二酚(PAR)作为显色剂,采用"多因素多水平可视化设计法"设计样本,在4种组分可见吸收光谱严重重叠的390~480 nm范围内,选取16个特征波长处的吸光度作为输入信号,应用"留二法"原则训练BP网络。网络准确预测了结果,Cd2+、Pb2+、Cu2+、As3+的平均回收率分别为100.10%、100.03%、100.09%、99.99%,测定结果的相对标准偏差分别为0.18%、0.12%、0.26%、0.13%,达到了4种组分含量同时测定的目的。     

多元线性回归-分光光度法测定电镀排放废水中重金属

采用多元线性回归-分光光度法进行电镀排放废水中Cr³⁺、Ni²⁺、Zn²⁺的同时测定研究。以4-(2-吡啶偶氮)间苯二酚(PAR)为显色剂，探索了同时测定模拟电镀废水中Cr³⁺、Ni²⁺、Zn²⁺的实验方法，建立多元线性回归模型。根据实际电镀排放废水中Cr³⁺、Ni²⁺、Zn²⁺的质量浓度分布调查结果，设计了测定较低和较高浓度范围2种模型，分别对应不同水质波动程度的电镀企业废水，前者浓度范围设置基本覆盖大多数实际电镀排放废水中Cr³⁺、Ni²⁺、Zn²⁺的浓度，且具有较高精度。测定浓度范围较小模型对应水质波动较小的电镀排放废水，模型中Cr³⁺、Ni²⁺、Zn²⁺的质量浓度分别为0.32～0.44、0.32～0.50、0.72～0.84 mg/L,平均相对误差MR...