Using geoaccumulation index to study source profiles of soil dust in China

Source apportionment studies of TSP （atmospheric particulate matter with aerodynamic diameters ≤ 100 μm） and PM10 （atmospheric particulate matter with aerodynamic diameters ≤ 10 μm） have revealed that soil dust is an important source of these particulates in China. In this study, the contamination of soil dust was assessed through the use of a geoaccumulation index （Igeo）. The mass concentration profiles of 17 elements （Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Br, Ba, and Pb） were established for urban soil dusts. Geochemical compositions of soils from 15 cities were used to represent background urban soil compositions. The results of this study indicated that a number of cities are severely polluted by particulates containing Ca, Cr, Ni, and Cu in both size fractions （TSP and PM10）. Contamination with Zn, Pb, Co, and Br was moderate to severe （Igeo 〉 2）. The Al and Fe concentrations were not high enough for them to be considered contaminants.

Mineralogical characteristics of soil dust from source regions in northern China

Mineral compositions of aerosol particles were investigated at four sites （Aksu, Dunhuang, Zhenbeitai, and Tongliao） in desert regions of northern China from March to May in 2001 and 2002 during the intensive field campaign period of ACE-Asia （Aerosol Characterization Experiments-Asia）. The X-ray diffraction （XRD） results show the main minerals for Asian dust are illite, chlorite, kaolinite, quartz, feldspar, calcite, and dolomite. Gypsum, hornblende, and halite are also detected in several samples. Semi-quantitative mineralogical data of aerosol samples show that carbonate content decreases from western to eastern source areas; that is, soil dust collected at western source area sites of Dunhuang and Aksu are enriched with carbonate, while northeastern source area site of Tongliao is associated with low carbonate content. But the spatial distribution of feldspar exhibits a different pattern as compared to carbonate, increasing from the western to the eastern sources. The total clay content is significantly higher （73% in average） at the deposition site of Changwu than those at source areas. Air-mass back trajectory studies for the three dust storm events observed at Changwu, showed that soil dust transport pathways were as expected from carbonate content for the source identification, further demonstrating that carbonate was a useful tracer for eolian dust on regional scale in northern China.

Effects of dust,soiling,aging,and weather conditions on photovoltaic system performances in a Saharan environment—Case study in Algeria

Solar photovoltaic(PV)power represents one of the most promising future sources of energy in the world.Considered the cleanest form of energy,extensive research is being undertaken to widen its use.Notably,mega projects are being considered for installation in the Middle East and North Africa(MENA)region because of its high solar potential,with hopes of eventually feeding Europe from the PV electricity generated in this region and transported through high voltage direct current(DC)lines.However,current implementation of PV systems has shown that their reliability and efficiency depend upon surrounding environmental factors,such as the ambient temperature,wind,and rainfall,as well as soiling,pollution,and aging.The aim of this study was to investigate,through experimental tests,the effects of such factors on the power output of a grid connected PV station.The results showed that the output power and efficiency are deeply affected by various environmental factors,which are weather dependent.These findings may help us develop appropriate solutions to overcome these drawbacks.

Speciation of heavy metals in airborne particles,road dusts,and soils along expressways in China

This study analyzed the concentrations and chemical forms of Zn,Cu,Pb,Sb,Cd and Mn in airborne particles,road dusts and soils collected along three expressways in Jiangxi Province,China,with different traffic densities,and identified the levels and sources of heavy metal contamination.The concentrations of Zn,Cu,Pb,Sb,and Cd except Mn in airborne particles,road dusts and soils were all in direct proportion to traffic volume.Cd concentrations were low compared with other metals.For instance,the concentrations of Zn,Cu,Pb,Sb,Mn and Cd were 6.6,0.7,2.2,0.1,0.1 and 0.1μg·m-3in PM10along the Changjiu Expressway,792.8,241.4,248.3,9.6,340.5and 8.0 mg·kg-1in road dusts,and 201.1,143.2,59.5,9.5,338.9 and 2.3 mg·kg-1in soils,respectively,but in the case of the ratio of concentration to the environmental background value,most serious contamination was caused by Cd.The sources of the heavy metals were judged by comparisons of the chemical forms of the heavy metals in different environmental media.Pb and Mn in airborne particles were both derived from traffic;Pb in road dusts and soils resulted mainly from the use of leaded gasoline in the past;and Mn in road dusts and soils was derived from parent rocks.Zn,Cu,Sb and Cd in airborne particles,road dusts and soils were derived primarily from traffic,and differences in chemical forms of the heavy metals in different media were due to the interaction between heavy metals in airborne particles and organic matter and other surfaces in road dusts and soils.We also discussed the change of chemical forms of heavy metals in particles of different sizes and under different weather conditions.Bioavailability of heavy metals in airborne particles was much higher than that in road dusts and soils,especially Pb(0.676 in airborne particles,0.159 in road dusts and 0.095 in soils).

Improvement of geotechnical properties of sabkha soil utilizing cement kiln dust

Improvement of properties of weak soils in terms of strength,durability and cost is the key from engineering point of view.The weak soils could be stabilized using mechanical and/or chemical methods.Agents added during chemical stabilization could improve the engineering properties of treated soils.Stabilizers utilized have to satisfy noticeable performance,durability,low price,and can be easily implemented.Since cement kiln dust(CKD) is industrial by-product,it would be a noble task if this waste material could be utilized for stabilization of sabkha soil.This study investigates the feasibility of utilizing CKD for improving the properties of sabkha soil.Soil samples are prepared with 2% cement and 10%,20% or 30% CKD and are tested to determine their unconfined compressive strength(UCS),soaked California bearing ratio(CBR) and durability.Mechanism of stabilization is studied utilizing advanced techniques,such as the scanning electron microscope(SEM),energy dispersive X-ray analysis(EDX),backscattered electron image(BEI) and X-ray diffraction analysis(XRD).It is noted that the sabkha soil mixed with 2% cement and 30% CKD could be used as a sub-base material in rigid pavements.The incorporation of CKD leads to technical and economic benefits.

Transport of atmospheric trace elements and dust－soil to the Western Pacific Ocean

Atmospheric aerosol and rainwater samples collected in the different Western Pacific area were analyzed by instrumental neutron activation and proton induced X-ray emission to (1) determine the atmospheric concentrations of trace elements over the Western Pacific and (2) to esti mate the atmospheric deposition of trace elements and dust-soil material to this region. High abundance of pollutant and crustal elements relative to oceanic sources was observed. Some characteristics of marine atmosphere relating to long-range transport of crustal and anthropogenic elements from continent to the remote ocean are discussed. The total dust-soil particle mass is estimated to be 0. 066-1.2 μg/m￣3 over the Western Pacific Ocean areas. Atmospheric inputs of dust-soil particles control the marine particle concentrations of crustal elements. In addition, the characteristics of marine rain water are discussed.

The Contribution of the GIS and the Principal Component Analysis in the Study of the Cement’s Dusts Impact on the Top Soils in the Central Part of the Oujda-Taourirt Corridor (Eastern Morocco)

Cement dust pollution is one of the sources of atmospheric pollution. The main impacts of the cement activity to the environment are the broadcasts of dusts and gases. The objective of this study is to determine the effects of cement dust pollution on physico-chemical characteristics of the soil at the vicinity of the cement factory in Oujda-Taourirt corridor (Eastern Morocco) using Principal component analysis (PCA) and geographical information system (GIS). Forty one (41) surface soils (0 - 3 cm) were collected from the six rural townships surrounding the cement factory. The collected soil samples were analyzed for their chemical properties (CaO, Al2O3, Fe2O3, K2O, MgO, SO3 and SiO2) as well as their pH and Electric Conductivity. The results of the analysis showed that the dusts emitted by the cement plant are especially basic and contain a high free lime (43.03% CaO). The principal component analysis applied on the 41 superficial soil samples, allows deducting that the free lime and the sulfur oxide are the tracer elements of this form of pollution. Furthermore, the spatial projection of the factor scores of the principal component analysis using the geographical information system permits us to determine the spatial distribution of more polluted areas of soils as well as to estimate their impact at a zone of 2.5 km of beam around the factory.

Using Poultry Litter Biochar and Rock Dust MB-4 on Release Available Phosphorus to Soils

Highly weathered soils in areas from Brazil are acidic soils, typically characterized by poor fertility, particularly with low soil phosphorus level. This laboratory experiment was carried out to evaluate the influences of biochar, made from the poultry litter and MB-4, rock dust from grinding of silicate rocks in increasing the available soil phosphorus on Ultisol, Oxisol and Entisol. Thus, one experiment involving soils incubation was conducted in laboratory, during 100 days. The treatments consisted of rock powder, MB-4 and poultry litter, biochar, evaluated by the base saturation method, with correction levels from 40% to 80% for Ultisol and Entisol and from 20% to 80% for Oxisol and three replicates. After the incubation period, the soil samples were analyzed in relation to available phosphorus in the soil. The results of this study confirmed that the biochar prepared from the poultry litter through slow pyrolysis was a potential source of phosphorus, particularly to weathered soils. Biochar released phosphorus into the soils. The biochar could be used in the improvement of available phosphorus for the three soils analyzed. During the incubation period, 100 days, the application of increasing doses of MB-4 in soils there was no improvement in the available soil phosphorus. MB-4 was not a source of phosphorus to the soil in a short term.

A Review on Stabilization of Expansive Soil Using Industrial Solid Wastes

In developing countries like India, Industrialization is rising rapidly, and also?a great paucity of land is there, the demand for exploitation of industrial?wastes?which coming from industries is increasing. From geotechnical perspective,?fly ash, granite and quarry waste, cement kiln dust, silica fume, rice husk etc.?are the waste materials?which?have effectual features requisites by an excellent soil stabilization admixture. Stabilization using solid wastes is one of the different?methods of treatment, to improve the engineering properties and make it?suitable for construction. This paper briefs about the recent trends in stabilization of expansive soil using industrial waste (granite and quarry waste, cement kiln?dust, silica fume, rice husk) as stabilizers for decreasing the environmental?hazards.

Gustiness and Coherent Structure of Strong Winds and Their Role in Dust Emission and Entrainment

After the passage of a cold front, spring in northern China, the outbreak of strong wind is often accompanied by dust emissions. Through analyses of data in the atmospheric boundary layer during a typical case, it is revealed there are rather regular gust wave packets superimposed on the basic strong wind flow. The gust-wind wave packets have a period equal to around 3 6 rains and possess coherent structure. As the vertical transport of momentum is decomposed into separate parts by （a） basic flow, （b） gust-wind, and （c） turbulence, they are all in a downwards direction at the lower levels of the atmospheric boundary layer during strong wind periods. However, （a） is the largest, while （b） and （c） are comparable. All these are very different from the case of normal weather. Besides, the friction velocity at the ground surface is also much larger than that of normal weather and should be corrected by taking the contributions of the basic flow and gust-wind into account.The strong basic flow with descending motion is very favorable for soil erosion and sand/dust emissions, but suppresses the entrainment of dust particles by keeping them within the bottom levels of the atmospheric boundary layer. Owing to the coherent structure of gust-wind, dust particles can effectively overcome the systematic descending air motion and penetrate into the middle and upper levels of the atmospheric boundary layer, and then propagate further and diffuse into the troposphere where ascending air motion prevails.

Preparation and Characterization of Impurely Irrigated Soil Adsorbent from Beaches

[Objective]We aimed to study the preparation methods of impurely irrigated soil adsorbent from beaches,as well as its ability to absorb phenol.[Method]Using hydrochloric acid as activator,we compared the influences of various soil adsorbents on the adsorption of phenol through the desired orthogonal tests where the usage of saw dust,concentration of hydrochloric acid,liquid-solid ratio and carbonization temperature varied.Afterwards,we characterized this soil adsorbent.[Result]The optimal conditions for preparing the soil adsorbent were as follows,that is,the usage of saw dust was 20%,concentration of HCl was 1 mol /L,the ratio of liquid to solid was 2:1,carbonization temperature was 500 ℃,and activation time was one hour,the absorption efficiency of phenol in water by the soil adsorbent reached above 90%.Characterization showed that the prepared soil adsorbent changed obviously in the structure,that is,soil pores and carbon content increased greatly,as well as its absorption efficiency.[Conclusion]The prepared soil adsorbent by this method greatly improved the absorption efficiency of phenol in water,which provided a novel method for the reasonable utilization of saw dust,with good prospects.

Element and mineral characterization of dust emission from the saline land at Songnen Plain, Northeastern China

Recent observations of Asian dust storms show an eastern expansion of the source area to degraded lands, where dust emissions have been little studied. The dust concentrations over the saline land of the western Songnen Plain （SSL）, Northeastern China, are circumstantially higher than those from the northwestern Chinese deserts. These concentrations are sensitive to the surface soil conditions and wind velocity on the ground. The dust samples collected during dust storm events on the SSL contain abundant Na, Mg, A1, K, Ca, Fe and Ti, as well as toxic elements such as Cu, V, Zn and Ba. Individual particle analysis reveals that fine saline particles （〈 10 μm in diameter） on the saline land, consisting largely of carbonate, halite and sulfate together with lithogenic minerals such as SiO2 and aluminosilicate, are eventually uplifted during the interval from spring to autuum. The predominantly fine saline particles uplifted from the SSL are likely transported eastward by the winter monsoon circulation and westerlies. Recent degradation of saline lands in Northeastern China would not only increase the frequency of dust storm events in the downwind area, but also might change the chemical composition of the Asian dust emissions.

Does Dust from Arctic Mines Affect Caribou Forage?

This study explores how dust from the Ekati Diamond Mine potentially affects the availability and quality of forage on the seasonal range of the Bathurst caribou herd. Understanding the effects of dust as a source of disturbance is important because the Bathurst caribou population has declined by 93% since the middle 1980s and there are reports that caribou in general may avoid mining projects. There are several challenges for quantifying dust impacts: 1) Natural variations (e.g., topography, natural disturbance, and soil pH) may also impact forage availability and quality for caribou. To minimize their masking effect, we stratified survey sites into seven land cover classes and selected the most populous class (i.e., the dwarf shrub) for assessing the impact. 2) Within class variation (e.g., the proportion of area covered by rocks where vascular plants and lichen do not grow) can further skew the analysis. We eliminated this problem by examining only the area not covered by rocks. 3) Coarse and fine suspended particulates have different spatial coverages, chemical compositions, and pH values. Consequently, their impacts on caribou forage can be different. To distinguish their impacts, we sampled two areas: transects from the Misery Haul Road that has been in active use vs. those from a rarely used spur road outside the Misery Camp. We sampled percent vegetation cover, soil pH, and dust on leaves along these transects during the summers of 2015 and 2016. Our results indicated that the amount of dust on leaves in a zone of ~1000 m from the Misery Haul Road was 3 - 9 times than that of background sites. The zone of reduced lichen percent cover was also about 1000 m. In contrast, these road dust-induced changes in caribou forage were not observed for the dust-free transect from the spur road.

微生物固化工程裸土抗风蚀扬尘性能试验研究

目的 岩土微生物技术在土木工程领域已广泛应用,本文基于微生物诱导碳酸钙沉积(MICP)固化土体技术,探究其固化土体的抗风蚀扬尘效果及固化机理。方法 利用巴氏生孢八叠球菌,对比分析微生物固化典型工程裸土建筑渣土和砂土试样和其洒水固化试样,通过风洞试验、表面强度测试、微观结构观测研究微生物固化试样抗风蚀扬尘性能,提出一种新型土壤抑尘措施。结果 根据风洞试验和表面强度测试结果发现:同比条件下,微生物固化试样风蚀质量累计损失远远低于洒水试样的,风洞试验后微生物固化试样表面强度虽有所下降,但其表面强度仍强于洒水试样,试验结果验证了微生物固化工程裸土提升其抗风蚀扬尘的可行性及其显著效能.基于电镜扫描和X射线能谱试验分析显示:渣土和砂土试样经微生物固化后,土颗粒表面和孔隙间均产生大量碳酸钙沉积,有效增强了土颗粒间黏结性能,但CaCO_(3)晶体结构在不同土壤中略有差异,在工程渣土试样中主要为片状结构、在砂土试样中为球状或球状堆积体结构。结论 微生物固化技术有效提升了土壤抗风蚀扬尘性能,且具备良好的时效性,对土壤防尘治理具有一定的参考价值。

聚丙烯酰胺涂覆改性生物炭的粉尘排放影响

针对生物炭在土壤改良中存在的粉尘排放问题,利用聚丙烯酰胺涂覆技术对生物炭表面改性,并开展粉尘排放试验对聚丙烯酰胺涂覆前后生物炭的粉尘排放效果进行研究。以南昌市新建区红壤为研究对象,通过盆栽试验进一步研究改性生物炭对土壤理化性质和植物生长的影响。结果表明:相比于直接施用生物炭,经聚丙烯酰胺涂覆处理后的改性生物炭可显著降低粉尘排放量。同时,生物炭和改性生物炭的施用均显著提高了土壤的pH值和有机碳、全氮、全磷、全钾的质量分数,并显著降低了土壤容重。此外,随着时间的推移,直接施用生物炭的土壤改良效果显著减弱,在30 d时各项指标降低了8.0%~22.9%,而改性生物炭对土壤理化性质的改良效果前后无显著性差异。

风流扰动下露天矿土质路面粉尘运移规律研究

为降低露天矿土质路面粉尘质量浓度,提高清洁生产水平,采用气固两相流理论,建立粉尘颗粒起动模型,分析粉尘起动风速及变化规律,利用实验研究进行验证,并确立粉尘运移规律以及运动形式,选取正交实验极差分析各因素对起尘量影响显著性。研究结果表明:粉尘起动风速与粉尘粒径、含水率、负荷均有函数关系;起尘量在粒径、含水率、负荷、风速4种因素下呈现不同变化规律,与粒径、风速均呈非线性关系,与含水率呈负相关,与粉尘负荷呈正相关,影响显著性为:粒径>负荷>风速>含水率;粉尘运动形式与风速和粒径相关,在5 m/s风速下,(0,75]μm粒径粉尘易做悬浮运动,(75,500]μm粒径粉尘易做跳跃运动,(500,1000]μm粒径粉尘易做蠕移运动。研究结果可为降尘措施提供理论指导。

察汗淖尔干涸湖区土壤盐渍化对地下水位响应

土壤盐渍化是产生坝上高原盐尘暴的主要物质来源,干涸湖区土壤盐渍化防控对于京津冀地区空气质量安全具有重要意义。本次研究以坝上高原察汗淖尔干涸湖区为例,探究地下水位埋深和溶解性总固体(total dissolved solids, TDS)与土壤盐渍化的影响,确定土壤盐渍化的地下水位防控阈值,为地表土壤盐渍化治理提供依据。室内实验获取研究区土壤含盐量、沙粒、黏粒百分含量,地下水TDS值,野外调查地下水位埋深,收集研究区蒸发量、降雨量资料,利用皮尔逊相关系数法及协方差矩阵分析选取线性关系较小的影响因素,绘制回归曲线探究土壤含盐量与地下水位埋深之间的关系。研究结果表明,TDS为0~1 000 mg/L、1 000~3 000 mg/L、3 000~6 000 mg/L、6 000~23 000 mg/L及0~23 000 mg/L时,土壤发生盐渍化的阈值分别为4.08、5.47、6.84、7.94、7.37 m;TDS为0~3 000 mg/L时土壤基本不发生盐化。TDS值为3 000~6 000 mg/L、6 000~23 000 mg/L及0~23 000 mg/L时土壤盐化阈值分别为2.05、2.44、1.97 m。本文研究利用回归分析,确定察汗淖尔流域平原区各TDS分区不同盐渍化程度对应的地下水位埋深,可针对性进行地下水位调控。

工地扬尘管控措施效果量化研究

随着城市规划建设,大规模建筑工程在地基开挖、主体建设、外墙装修过程中,会产生以粗颗粒物(PM_(10))为代表的众多大气污染物。为尽量减少建筑工地扬尘产生PM_(10),相关部门要求建筑工地采取裸土覆盖、立体喷淋、围挡隔离等抑尘措施。基于现场抑尘措施控制试验和高精度数值风洞试验对各措施的抑尘效果进行逐一探究。结果表明:只开围挡喷淋时PM_(10)浓度下降5.1%,只开施工喷淋时浓度下降12.3%,二者全开时浓度下降11.4%。风速较大时,裸土覆盖的抑尘效果比小风天气显著,在三级风(大于2 m/s)下裸土覆盖的PM_(10)浓度均值相比裸土不覆盖时平均下降10.7%。裸土喷淋后的PM_(10)浓度比不喷淋时下降21.3%。整体上基坑阶段在围挡2、3、4和5 m时的扬尘削减率分别为3.6%、10.5%、18.4%和29.0%。在主体阶段,随着排放源的升高,扬尘扩散的影响距离逐渐降低。当源高10 m时,最大影响距离为工地外75 m;当源高30 m时,最大影响距离为工地外50 m;当源高50和90 m时,刚出工地的扬尘逸散率便在10%以内,即对工地外的影响可以忽略。

啮齿类实验动物健康监测用脏垫料哨兵动物法和排风粉尘PCR法比较

实验动物微生物质量对科学研究数据的有效性和重复性以及人类健康和动物福利至关重要。目前,独立通风笼具(individualventilationcage,IVC)已成为主流的啮齿类实验动物饲养系统。针对这种饲养方式的病原体监测方法最常用的是脏垫料哨兵动物法(soiledbeddingsentinels,SBS),该方法是以间接接触和延迟反馈的方式监测鼠群的微生物携带状况,能有效监测通过粪-口途径传播的病原体如小鼠肝炎病毒、呼肠孤病毒等。但这种方法难以监测到主要通过气溶胶、直接接触等途径传播的病原体,例如仙台病毒、嗜肺巴斯德杆菌等。排风粉尘(exhaustairdust,EAD)-PCR监测方法分为在IVC笼架排风管道中拭子采样,用以监测管道相对应的笼架;主机初效过滤前拭子采样,用以监测整个IVC笼架;EAD收集装置采样,用以监测同一个主机连接的所有笼架。不同IVC厂商针对各自的IVC系统开发了相应的EAD收集装置,使操作便捷,容易实现标准化。目前,与SBS方法相比,EAD-PCR方法的检出率和时效性都有显著提升,最快暴露一周就可检出,可作为SBS方法的补充或替代,有利于维护实验动物福利。本文对上述两种病原体监测方法的应用进展进行综述,同时结合本实验室和送检单位EAD-PCR监测的实施情况,对该方法存在的局限性进行分析并提出解决方案。EAD-PCR方法有助于减少活体哨兵动物的使用量,可以更好地维护实验动物福利的“3Rs”原则。

贵州独山降尘-土壤-水体重金属分布特征

以贵州省独山县大气降尘、雨水、土壤与灌溉水样品为研究对象,对其重金属元素地球化学特征进行了分析,并对其重金属污染情况进行了评价。分析结果表明:大气降尘中重金属元素主要有As、Cd、Cr、Hg和Pb,含量排序为Hg<Cd<As<Cr<Pb;雨水重金属中元素主要有As、B、F、Hg、Pb和Zn;研究区土壤偏酸性,135件表层土壤样品中元素As、Cr、Cu、Hg、Ni、Pb、Zn、Mn和Se的含量、土壤pH值与Cd的含量均呈显著正相关;灌溉水中重金属元素单因子污染指数大多数为1级,属清洁范围,仅2件样品中元素Hg为轻度污染。评价结果显示:研究区内大气降尘年通量密度平均值排序为Hg<Cd<As<Cr<Pb;土壤中Cd单因子污染指数最高,其污染贡献最大;内梅罗综合污染指数大小排序为麻尾镇和平村>基长镇尧新村>上司镇王龙村;地累积指数I_(geo)、潜在生态风险指数Er研究表明,元素Hg、Cd危害指数占比较高;灌溉水水质绝大多数达标,仅2件样品中Hg超标;土壤剖面中除Cr以外,As、Cu、Pb、Zn、Hg、Cd和Ni均具有母质层→淀积层→林滤层含量富集规律,尤其在淀积层至林滤层阶段富集加剧。研究区大气降尘主要来源为燃煤尘、交通尘;土壤重金属元素Cd超标,其污染来源为地质背景、采矿活动、工业三废和燃煤源;灌溉水Hg超标可能源于大气降尘。