On the spatial and temporal variations in atmospheric concentrations of hexachlorobenzene and hexachlorocyclohexane isomers at several locations in the province of Ontario,Canada

Hexachlorobenzene (HCB), as well as α- and γ-hexachlorocyclohexane (HCH) have been measured at seven sites in Ontario, Canada during the years 1985–1989. While two of the locations were close to a suspected source of the organochlorines, five were sites that reflected the non-urban airshed loadings which are considered to be regionally representative of the Great Lakes. At the non-urban locations, the γ-HCH (lindane) and α-HCH concentrations ranged from 15 to 190 pg m⁻³ (mean of 47 pg m⁻³) and 50 to 660 pg m⁻³ (mean of 240 pg m⁻³), respectively. The HCB concentrations varied from 20 to 310 pg m⁻³ (mean of 94 pg m⁻³). At the suspected source locations, the α:γ HCH ratio was less than unity while at locations distant from known or suspected sources, the α:γ ratio was usually greater than 7. At the non-urban locations, the highest concentrations of the α- and γ-HCH isomers were observed during the summer and the lowest concentrations were seen during the winter. The concentration of HCB, however, remained relatively constant throughout the year.     

Upper Yellow River air concentrations of organochlorine pesticides estimated from tree bark, and their relationship with socioeconomic indices

Organochlorine pesticide(OCP) concentrations in tree bark from the upper Yellow River region were determined. Total OCP concentrations ranged from 2.7 to 82 ng/g dw, with a mean of 20 ng/g dw. Concentrations of total(Σ) DDTs(0.49–37 ng/g dw), HCHs(0.55–4.5 ng/g dw), and HCB(0.1–1.0 ng/g dw) were much higher than the other OCPs and accounted for 89% of the ΣOCP concentrations. p,p′-DDT was the dominant member of the DDT pesticide group and-HCH was the dominant HCH isomer. The p,p′-DDT/p,p′-DDE and-HCH/-HCH ratios suggested that there were recent DDT and-HCH releases. OCP concentrations in the air were estimated from the tree bark, and the estimated median ΣDDTs, ΣHCHs, and HCB concentrations in the air were 0.09, 0.14, and 0.024 pg/m3, respectively. The relationship between total OCP concentrations and socioeconomic and natural environment indices were assessed using multiple linear regression analysis, and a regression equation including all these factors was obtained. Population density and tertiary industry were the two dominant factors that appeared to affect OCP concentrations in the upper Yellow River region.     

长江武汉段水体悬浮物中有机氯农药的残留状况

以α-HCH,β-HCH,γ-HCH,δ-HCH,p,p′-DDE,p,p′-DDD,o,p′-DDT,p,p′-DDT和HCB等9种有机氯农药为目标污染物,采用索氏提取和气相色谱法,对长江武汉段水体悬浮物中有机氯农药的残留进行调查分析。调查发现,在长江武汉段水体悬浮物中,六氯苯(HCB)、六六六(HCHs)和滴滴涕(DDTs)类有机氯农药均被检出,其中六氯苯(HCB)在表层沉积物中的残留量(质量分数)为0 37～9 06ng g,平均为2 89ng g;六六六类农药在悬浮物中的残留量(质量分数)为0 23～1 90ng g,平均为0 76ng g;滴滴涕类在悬浮物中的残留量(质量分数)为0 18～4 67ng g,平均为1 31ng g。在长江武汉段水体悬浮物中,HCB,p,p′-DDE和γ-HCH的被检出率和残留量均最高,为主要污染物。      

Biogenic and anthropogenic organic compounds in eolian particulates in the East Mediterranean region—I. Occurrence and origin

Lipids of biogenic and anthropogenic origin were determined in aerosol samples, collected seasonally, in a coastal area on the north of the island of Crete. Lipid classes such as n-alkanes, hopanes, polycyclic aromatic hydrocarbons, fatty alcohols, fatty acids, fatty acid salts and α,ω-dicarboxylic acids were characterized by GC/MS and GC/FID analysis, in terms of their contents of homologous compound series. The concentrations ranged between 56 and 215 ng m⁻³ for n-alkanes, 10 and 52 ng m⁻³ for polycyclic aromatic hydrocarbons, 2 and 31 ng m⁻³ for fatty alcohols, 13 and 279 ng m⁻³ for fatty acids, 24 and 220 ng m⁻³ for fatty acid salts and 0.4 and 7.5 ng m⁻³ for α, ω-dicarboxylic acid salts. The prevailing winds were influencing the composition of the eolian particles. Generally, aerosols sampled during south wind events predominantly contained lipids originating from higher plants, while when north and northwest winds prevailed the major components were of marine origin. The absence of unsaturated fatty acids in all aerosol samples is related to the presence of α,ω-dicarboxylic acids, which are believed to be their photo-oxidation products.     

若尔盖高原湿地地表水与大气湿沉降中有机氯农药和多氯联苯研究

采用高分辨率气相色谱-高分辨率质谱联用法分析位于青藏高原东缘的若尔盖高原牧场地表水和大气湿沉降中有机氯农药(OCPs)和多氯联苯(PCBs)异构体含量的季节分布特征,探讨持久性有机污染物(POPs)在边远清洁地区的地球化学行为.结果表明,若尔盖地区地表水中∑HCHs、∑DDTs、HCB、∑6PCBs平均浓度分别为0.90,1.36, 0.95,1.35ng/L.大气降水中OCPs和PCBs平均浓度分别为0.363,0.118ng/L,最大值出现在11月初冬的降雪样品中.异构体按平均浓度排序为HCB > PCB28 > p,p’-DDD > p,p’-DDE > α-HCH > γ-HCH.PCBs以PCB28和PCB52为主,除少量的PCB101外,其余高氯代PCB化合物都未在沉降样品中检出.∑HCHs、∑DDTs、∑PCBs的大气沉降通量分别为0.058~0.268,0.087~0.311,0.049~0.188ng/(m2·d).高海拔地区POPs大气沉降模式可分为“海拔梯度降水型”和“高原型”2类.类似于极地冷凝作用,高原型降雪中的POPs的沉积通量高于降雨沉降通量,但持久性较强的PCB138、PCB153和PCB180则缺失.这一结果验证了高空大气远程迁移和局地的高山冷凝效应的区别.     

北京石景山区夏季大气中有机氯农药的研究

利用气相色谱对北京石景山区大气中气态和总悬浮颗粒物中有机氯农药(OCPs)含量进行了分析测定.结果表明,北京石景山区大气中气态和颗粒物中HCHs、p,p￠- DDT、p,p￠-DDE、p,p￠-DDD、o,p￠-DDT、七氯、氯丹的平均含量分别为:4344.4, 1000.2, 778.0, 213.4, 1319.3, 645.7, 376.6 pg/m3和37.3, 5.3, 0, 0.7, 15.8, 1.6, 0.6 pg/m3,有机氯农药主要以气态存在于大气中.HCHs和DDTs是有机氯农药类污染物的主要成分,两者之和在气态和颗粒物中所占总OCPs的比例分别为87.2%和90.9%.α-HCH/γ-HCH 和p,p’-DDE/p,p’-DDT的浓度比值分别<1.5和<1.0,表明新近该区大气中有γ-HCH和DDT的输入.三氯杀螨醇的使用是环境中DDTs的一个重要来源.     

利用SPMD技术监测珠江三角洲大气有机氯农药

利用半渗透膜装置(SPMD)对珠江三角洲地区大气有机氯农药(OCPs)进行了分季度为期1年的监测分析。结果显示,该地区大气OCPs主要为DDTs,HCHs,氯丹和甲氧基氯,DDTs的含量约占总量的62%～88%。珠江三角洲地区大气有机氯农药时空分布差异明显,OCPs含量夏季高于冬季;各地区大气有机氯农药的年均含量为3 8～27 5ng d,香港和珠海较低(平均为5 0ng d),广州(GZ01)最高,年均值达27 5ng d。大气中m(DDT) m(DDD+DDE)均大于1,表明近期该地区大气中仍有新的DDT输入,对α-HCH和α-氯丹的手性特征进行了分析,它们的旋光异构体比值(年均值)(ER(+-))分别为0 75和0 69。夏季大气与土壤中α-HCH的ER(+-)相当,而冬季大气ER(+-)要低于土壤,表明夏季大气α-HCH基本来自于土壤中α-HCH的挥发,而冬季大气α-HCH可能来自土壤挥发与外来源迁移的组合。      

Heterogeneous sulfur conversion in sea-salt aerosol particles: the role of aerosol water content and size distribution

Meteorological and chemical conditions during the July 1988 Bermuda-area sampling appear to have been favorable for conversion of sulfur gases to particulate excess sulfate (XSO₄). Observed average XSO₄ and SO₄ concentrations of 11 and 2.1 nmol m⁻³, respectively, at 15 m a.s.l. in the marine boundary layer (MBL) upwind of Bermuda, indicate that conversion of SO₂ to XSO₄, over and above homogeneous conversion, may be necessary to explain the > 5.0 average molar ratio of XSO₄ to SO₂. Given an observed cloud cover of <15% over the region and the <3 nmol m⁻³ SO₃ concentrations observed by aircraft, heterogeneous conversion mechanisms, in addition to cloud conversion of SO₂, are necessary to explain the observed 11 nmol XSO₄ m⁻³.Aerosol water content, estimated as a function of particle size distribution plus consideration of SO₂ mass transfer for the observed particle size distribution, shows that SO₂ was rapidly transferred to the sea-salt aerosol particles. Assuming that aqueous-phase SO₂ reaction kinetics within the high pH sea-salt aerosol water are controlled by O₃ oxidation, and considering mass-transfer limitations, SO₂ conversion to XSO₄ in the sea-salt aerosol water occurred at rates of approximately 5% h⁻¹ under the low SO₂ concentration, Bermuda-area sampling conditions. All of the 2 nmol XSO₄ m⁻³ associated with sea-salt aerosol particles during low-wind-speed, Bermuda-area sampling can be explained by this conversion mechanism. Higher wind speed, greater aerosol water content and higher SO₂ concentration conditions over the North Atlantic are estimated to generate more than 4 nmol XSO₄ m⁻³ by heterogeneous conversion of SO₂ in sea-salt aerosol particles.     

西安城区大气有机氯农药的污染特征及来源分析

采用大流量主动采样器于2008年7—10月对西安城区大气进行采集,共获得颗粒态和气态样品24个,并对其中含有的17种有机氯农药(OCPs)进行了分析.结果表明:西安城区大气中ρ(α-硫丹)和ρ(β-硫丹)最高,分别为260.7和212.0pg m3,ρ(DDTs)(DDTs=o,p′-DDD+o,p′-DDT+o,p′-DDE+p,p′-DDD+p,p′-DDT+p,p′-DDE)为167.4pgm3,ρ(HCHs)(HCHs=α-HCH+β-HCH+γ-HCH)为199.3pgm3,ρ(trans-氯丹)和ρ(cis-氯丹)分别为104.0和97.3pgm3,ρ(六氯苯)为74.9pgm3,且都主要分布在气相中.来源分析表明,西安大气中DDTs受三氯杀螨醇的影响显著,而HCHs则主要来源于林丹的使用残留.α-HCH,HCB,p,p′-DDE及p,p′-DDT主要受污染物长距离传输影响,而γ-HCH,trans-氯丹,cis-氯丹,α-硫丹和β-硫丹主要受采样点周边地表挥发的影响.     

Hydrophobic organic chemicals in urban fog

The concentrations and aqueous/particle distributions of three classes of hydrophobic organic chemicals, n-alkanes, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs) were measured during the autumn of 1986's fog events in the urban area of Zürich, Switzerland. Concentrations of the chemicals in fog were in the range of 10–110 ng ml⁻¹ for n-alkanes (C₁₉–C₃₅), 6–60 ng ml⁻¹ for PAHs (21 compounds) and 7–22 ng ml⁻¹ for PCBs (31 congeners). In many samples, the concentration of individual n-alkanes and PAHs exceeded their water solubility, probably due to their association with dissolved and/or colloidal organic matter. All of the PAHs, except for phenanthrene, were measured as part of the particulate phase. Both the n-alkanes and PCBs showed a trend of increasing particle association with increasing hydrophobicity, but the trends were distinctly different. The presence of PCBs, PAHs, and n-alkanes at these concentrations suggest that fog is an excellent scavenger of hydrophobic organic chemicals. For a forested area near Zürich, Switzerland, it was estimated that the deposition of n-alkanes and PAHs by fog may be about equal to deposition via rain, but that fog may be 100 times more important than rain for the deposition of PCBs.     

北京地区雨水中溶解态有机氯农药的特征及源解析

对2006年5月~2007年11月北京地区雨水中溶解态有机氯农药(OCPs)的组成特征进行分析并对其进行源解析.结果表明,DDTs、HCHs、七氯、氯丹、六氯苯、艾氏剂和狄氏剂7种OCPs被检出,其平均浓度分别为(6.66±4.99)ng/L,(10.30±12.39)ng/L,(2.62±1.87)ng/L,(6.54 ± 4.58)ng/L,(3.99±3.02)ng/L,(2.10±1.40)ng/L和(2.25±1.58)ng/L.OCPs的总浓度在研究期间内呈总体下降趋势,表明北京地区的OCPs污染得到了较好的控制.通过对特征化合物的解析发现,有疑似的林丹和三氯杀螨醇的输入源,各化合物之间显著的相关性说明OCPs的输入途径相似.雨水中的OCPs含量与温度不相关;与降雨量和相对湿度有弱的负相关性;其沉降通量与空气中污染物的浓度相关,与降水量相关性不显著.     

北京地区地表水中OCPs和PCBs的污染分析

在夏、冬两季对北京地区密云,潮白河,玉渊潭和通惠河等地表水中17种有机氯农药（OCPs）和84种多氯联苯（PCBs）的含量进行了分析及来源解析.实验结果表明,OCPs总量在7.86～53.1ng/L之间,平均值为（16.9±14.6）ng/L.PCBs总量在2.99～32.7ng/L之间,平均浓度为（10.9±10.4）ng/L.HCHs,硫丹,DDTs和HCB是主要的OCPs污染物,其含量分别为（13.9±11.5）ng/L,（2.20±2.01）ng/L,（0.63±1.51）ng/L和（0.12±0.14）ng/L.α-HCH/γ-HCH平均比值为1.53,小于工业HCH中比值4～7,表明北京地区地表水中存在林丹的使用.而DDT/（DDD+DDE）比值<1.22,表明北京地区并无新的DDTs污染源输入环境.PCBs以低氯代联苯为主,其中二氯,三氯,四氯和五氯联苯总和占∑₈₄PCBs总量的79.2%.北京地区地表水中不同氯取代数PCBs组成与我国历史PCB产品组成相符,均以低氯代联苯为主,表明北京地区地表水中PCBs污染来源为历史使用.相比于国内其他区域水质而言,北京地区地表水OCPs和PCBs污染水平较低.     

Photocatalytic remediation of γ-HCH contaminated soil induced by α-Fe2O3 and TiO2

Heterogeneous photocatalytic degradation of γ-HCH on soil surfaces was carried out to evaluate the photocatalytic effectiveness of α-Fe2O3 and TiO2 toward degrading γ-HCH on soil surfaces. After being spiked with γ-HCH, soil samples were loaded with α-Fe2O3 or TiO2 and exposed to UV-light irradiation. Different catalyst loads(0%, 2%, 5%, 7%, and 10% (wt). α-Fe2O3; 0%, 0.5%, 1%, 2% wt. TiO2) were tested for up to 7 d irradiation. The effects of soil thickness, acidity, and humic substances were also investigated. The obtained results indicated that the γ-HCH photodegradation follows the pseudo-first-order kinetics. The addition of α-Fe2O3 or TiO2 accelerates the photodegradation of γ-HCH, while the photodegradation rate decreases when the content of α-Fe2O3 exceeds 7%(wt.). The degradation rate increases with the soil pH value. Humic substances inhibit the photocatalytic degradation of γ-HCH. Pentachlorocyclohexene, tetrachlorocyclohexene, and trichlorobenzene are detected as photodegradation intermediates, which are gradually degraded with the photodegradation evolution.     

Observation of possible elemental sulfur in the marine atmosphere and speculation on its origin

Samples obtained during research cruises in the North Atlantic and the North Pacific showed possible evidence of gas-phase elemental sulfur, S₈. Though the sampling and analytical method are still untested for this sulfur species, these data represent the first suggestion that this sulfur species exists in the marine troposphere. Concentrations of S₈ were ∼ 1 ng m⁻³ or less, though these measurements may represent a lower limit of the true ambient concentration. Though there are only few data, concentrations of elemental sulfur appear to be elevated near coastal or continental margins in the North Atlantic. Possible sources of elemental sulfur include direct vaporization during the sulfur processing, automotive emissions, geothermal emissions, and heterogeneous oxidation of reduced sulfur in cloud droplets.     

南京地区典型有机污染物长距离输送潜力研究

为研究典型有机污染物在南京地区的长距离输送潜力,以p,p’-DDT、γ-HCH、BaP和HCB为研究对象,运用TaPL3模型计算了其在研究区大气及水体中的长距离输送潜力.结果表明,BaP和p,p’-DDT通过大气的特征迁移距离(CTD)较小,分别为198 km和255 km,表现为大气污染长距离输送能力较小,污染较难扩散;而γ-HCH和HCB则更倾向于通过水体或大气进行长距离输送,其水体CTD分别为91 558 km和19 056 km,大气CTD分别为1 858 km和21 104 km,有利于其在研究区的扩散;水对γ-HCH和HCB的黏着度为负值,分别为-2.1和-54.86,表明γ-HCH和HCB更倾向于滞留在大气环境中,其通过大气并达到稳态后在大气中的质量分数为0.551%和2.2%;通过水体且达到稳态后在大气中的质量分数为0.149%和1.05%,高于p,p’-DDT和BaP.     

Measurements of atmospheric HNO3, HCl and associated species on a small network in eastern England

Measurements of gaseous HNO₃, HCl and NH₃ and particulate NO₃⁻, SO₄²⁻, Cl⁻ and NH₄⁺ have been made at a small network of sites in eastern England using sampling intervals from 3 h to 7 days. Both HCl and HNO₃ are spatially rather uniform, with some variation apparently due to spatial variations in NH₃, which stoichiometrically exeeded the sum of both gaseous acids. Mean concentrations of NH₃, HCl and HNO₃ between February 1987 and January 1988 were 1.90, 0.67 and 1.01 μg m⁻³, respectively. Pollution roses revealed low NH₃ concentrations, and high associated HCl and HNO₃ with winds from the North Sea. HCl, but not HNO₃ showed an appreciable elevation in concentration on the sector NW from our site, which we speculate may be due to the large capacity of coal-fired power stations in this upwind sector. Three-hourly data have been examined for diurnal effects and its is concluded that nocturnal formation of NO₃⁻ is occurring.     

Seasonal variation and sources of derivatized phenols in atmospheric fine particulate matter in North China Plain

Qualitative and quantitative analyses of derivatized phenols in Beijing and in Xinglong were performed from 2016 to 2017 using gas chromatography-mass spectrometry.The results showed substantially more severe pollution in Beijing.Of the 14 compounds detected,the total average concentration was 100 ng/m~3 in Beijing,compared with 11.6 ng/m~3 in Xinglong.More specifically,concentration of nitro-aromatic compounds(NACs)(81.9 ng/m~3 in Beijing and 8.49 ng/m3 in Xinglong) was the highest,followed by aromatic acids(14.6 ng/m~3 in Beijing and 2.42 ng/m~3 in Xinglong) and aromatic aldehydes(3.62 ng/m~3 in Beijing and 0.681 ng/m~3 in Xinglong).In terms of seasonal variation,the highest concentrations were found for 4-nitrocatechol in winter in Beijing(79.1±63.9 ng/m~3) and 4-nitrophenol in winter in Xinglong(9.72±8.94 ng/m~3).The analysis also revealed diurnal variations across different seasons.Most compounds presented higher concentrations at night in winter because of the decreased boundary layer height and increased heating intensity.While some presented higher levels during the day,which attributed to the photo-oxidation process for summer and more biomass burning activities for autumn.Higher concentrations appeared in winter and autumn than in spring and summer,which resulted from more coal combustions and adverse meteorological conditions.The significant correlations among NACs indicated similar sources of pollution.Higher correlations presented within each subgroup than those between the subgroups.Good correlations between levoglucosan and nitrophenols,nitrocatechols,nitro salicylic acids,with correlation coefficients(r) of 0.66,0.69 and 0.69,respectively,indicating an important role of biomass burning among primary sources.     

Simultaneous monitoring of PCB profiles in the urban air of Dalian, China with active and passive samplings

The concentration of polychlorinated biphenyls (PCBs) in the urban air of Dalian, China was monitored from November 2009 to October 2010 with active high-volume sampler and semipermeable membrane device (SPMD) passive sampler. The concentration of PCBs (particle + gas) ( ∑ PCBs) ranged from 18.6 to 91.0 pg/m 3 , with an average of 50.9 pg/m 3 , and the most abundant dioxin-like PCB (DL-PCBs) was PCB118. The WHO-TEQ values of DL-PCBs were 3.6-22.1 fg/m3 , with an average of 8.5 fg/m 3 , and PCB126 was the maximum contributor to ∑ TEQ. There was a much larger amount of PCBs in the gas phase than in the particulate phase. The dominant PCB components were lower and middle molecular weight PCBs. With increasing chlorination level, the concentration of the PCB congeners in the air decreased. The gas-particulate partitioning of PCBs was different for the four seasons. The gas- particulate partitioning coefficients (logK p ) vs. subcooled liquid vapor pressures (logP L 0 ) of PCBs had reasonable correlations for different sampling sites and seasons. The absorption mechanism contributed more to the gas-particulate partitioning process than adsorption. Correlation analysis of meteorological parameters with the concentration of PCBs was conducted using SPSS packages. The ambient temperature and atmospheric pressure were important factors influencing the concentration of PCBs in the air. The distribution pattern of the congeners of PCBs and the dominant contributors to DL-PCBs and TEQ in active samples and SPMDs passive samples were similar. SPMD mainly sequestrated gas phase PCBs.     

Excess particulate and gaseous bromine at a remote coastal location

Samples were collected at remote sites on the Isle of Harris, off the northwest coast of Scotland, to determine levels of particulate Br and gaseous Br trapped on base-impregnated filters. Lead and Na were also measured so that an estimate of the Br contribution from sea salt and vehicular pollution could be made. Particulate Br levels of more than double this estimated amount were recorded, with ‘excess’ Br concentrations of up to 54 ng m⁻³ being measured. Gaseous Br (believed to be mainly in the form of HBr) was found in similar, or somewhat higher, concentrations as particulate Br, with a mean of 28 ng Br m⁻³, compared with the mean particulate level of 21 ng m⁻³. It is conjectured that a similar situation exists at these sites as has been observed in the Arctic spring, where it appears that biochemically produced organobromine gases are photolyzed, with the subsequent removal of O₃ and formation of both particulate Br and gaseous HBr. This may represent an important global source of reactive Br and a potential O₃ sink in the marine troposphere.     

Atmospheric coarse particulate concentrations and dry deposition fluxes for ten metals in two urban environments

The atmospheric coarse particle concentrations of ten metals (Al, Ca, Cd, Cu, Fe, Mn, Ni, Pb, Si and Zn) were measured with the Noll Rotary Impactor (NRI) in the Los Angeles Basin (Claremont) California, and in Chicago, Illinois. The dry deposition fluxes were also measured for the ten elements at the Chicago site. An evaluation of the data demonstrates that the coarse particle mass could be divided into two categories: (1) material that was primarily of crustal origin (Al, Ca, Fe and Si) and (2) material that was primarily of anthropogenic origin (Cd, Cu, Mn, Ni, Pb and Zn). The mass of crustal material varied between 15 and 50% of the total coarse particle mass, while the mass of anthropogenic material was <1%. The dry deposition fluxes for the crustal material were between 20 (Al) and 200 (Si) ng m⁻² s⁻¹ while the fluxes for the anthropogenic material were between 1 and 7 ng m⁻¹ s⁻¹ for Cu, Mn, Pb and Zn. The cadmium (Cd) flux averaged 0.02 ng m⁻² s⁻¹.