Magnetic particles of industrial origin in different environments——Measurements, identification and significance

Various anthropogenic activities, in particular industrial processes based on combustion of fossil fuel, produce iron-oxides, which, being included in fly ashes, are transported through atmospheric pathways and deposited on ground. Upon deposition, they penetrate soils or water sediments, and can be easily detected due to their specific magnetic signature. In many cases, he presence of these magnetic particles is closely related to the presence of anorganic contaminants-heavy metals. This correlation is mainly due to coexistence, from the source to the deposition. Correlation with organic pollutants has been also reported, but this needs further detailed studies. In our contribution, we plan to review typical examples of such anthropogenic magnetic particles, with their source-specific features. We will highlight the methods of their identification in different environments, and laboratory characteristics.     

Environmental magnetic and geochemical characteristics of Chennai coastal sediments,Bay of Bengal,India

In this study, environmental magnetic, heavy metal and statistical analyses were conducted on 21 surface sediments collected from Chennai coast, India, to examine the feasibility of heavy metal pollution using magnetic susceptibility. The Chennai coastal sediment samples are dominated by ferrimagnetic minerals corresponding to magnetite-like minerals. The percentage of frequency dependent magnetic susceptibility reflects the presence of super-paramagnetic/single domain magnetic minerals in Chennai harbour, Cooum and Adayar rivers sediments. High pollution load index in sample E1, E2, CH7, C11, C12 and A16 is mainly due to anthropogenic activities such as, harbour activities, Cooum and Adayar rivers input and industrial effluent. Factor analysis shows that the magnetic concentration dependent parameters (χ, χ _ARM and SIRM) covary with the heavy metal concentrations, suggesting that the input of magnetic minerals and heavy metals in Chennai coastal sediments are derived from the same anthropogenic sources. Strong correlation obtained between pollution load index (PLI) and concentration dependent parameters (χ, χ _ARM and SIRM) for the polluted samples with magnetic susceptibility excess of 50×10^− 8 m³kg^− 1. Significant correlations between heavy metals and magnetic susceptibility point out the potential of magnetic screening/monitoring for simple and rapid proxy indicator of heavy metal pollution in marine sediments.     

三峡库区消落带土壤磁性变化规律及成因探讨

为动态跟踪三峡库区消落带土壤物性在水位上涨后所受影响,选择重庆市忠县石宝寨镇长江左岸一带作为研究区,以消落带外同类型土壤作对照,从分析不同水位土壤的磁学性质入手,探究三峡库区蓄水前后土壤性质对环境变化的响应。库区蓄水后,不仅导致了消落带内土壤理化性质变化,还使土壤磁性空间分布在不同水位这一维度上发生显著改变。消落带监测断面数据显示,土壤磁性由蓄水前垂直方向上较稳定的分布,变为目前整体上随淹没水深增加而增高的特征;169~175 m高程附近,土壤磁性接近当地同类土壤背景值,而低于此高度尤其是低于157 m后,磁化率值迅速增高。磁性的变化是库区蓄水后土壤磁性矿物组成发生改变造成的,由热磁曲线可知,次生磁铁矿的加入是首要原因。扫描电镜下观测出的浑圆状磁铁矿的最可能来源是上游燃烧化石燃料排放的磁性外来污染物,其随江水输运至此并沉积吸附在土壤颗粒上。研究结果为间接监测污染物的迁移提供了依据。     

Variations of continental discharge pattern in space and time: implications from the Laptev Sea continental margin, Arctic Siberia

Variations in sediment input and distribution to the Laptev Sea continental margin during the Holocene and Termination I could be identified based on radiocarbon dated magnetic susceptibility logs and sediment thickness in high-resolution seismic profiles. Magnetic susceptibility of surface samples reveals an increased input of magnetic grains to the Laptev Sea deriving from the Anabar and Khatanga river catchments. Exposed magnetite schists and volcanic rocks of the Anabar shield and Putoran Plateau, respectively, function as major source of magnetic material. The distribution of magnetic susceptibility in association with the thickness of the Holocene sediments indicates bottom-current induced sediment transport guided by major submarine valleys on the Laptev Sea shelf. The sites of filled paleoriver channels identified in the seismic profiles suggest that during the Late Weichselian sea-level lowstand river runoff continued through four of the major valleys on the exposed Laptev Sea shelf. The sediments at the top of the lowstand deposits in front of the Anabar-Khatanga valley, represented in the seismic profiles by prograding deltas, are characterized by outstandingly high magnetic susceptibility values. Radiocarbon datings approximate the deposition of these high magnetic sediments between 10 and 13.4 ka. It is suggested that this increased input of magnetic material is related to the deglaciation of the Anabar shield and the Putoran Plateau and thus support their glaciation during marine isotope stage (MIS) 2.     

Magnetic parameters,trace elements,and multivariate statistical studies of river sediments from southeastern India: a case study from the Vellar River

This contribution constitutes a new study using magnetic parameters and trace element determinations of pollutants in river sediments from the Tamil Nadu state. The Vellar River covers a total length of about 200 km and flows into the Bay of Bengal. Sediment samples were collected at different sediment depths (up to 90 cm) from 12 sites to investigate their magnetic properties (27 samples) and the contents of trace elements (21 out of 27 samples) along the river; as well as to perform magnetic studies for various grain size fractions (16 sub samples). The magnetic results of magnetic susceptibility and remanent magnetizations suggest that the magnetic signal of these sediments is controlled by ferrimagnetic minerals magnetite-like minerals and a minor contribution of antiferromagnetic carriers (such as hematite minerals). Detailed studies of selected samples showed a higher magnetic concentration in finer grain-sized fractions and a slightly different magnetic mineralogy. Magnetic concentration-dependent parameters evidenced high values, which, together with the background values, allowed us to identify magnetic enhancement at some sites. The Pearson correlation and multivariate statistical studies (Principal Component Analysis, Canonical Correlation Analysis) supported the relationship between the magnetic and chemical variables; in particular, magnetic susceptibility, anhysteretic and isothermal remanent magnetization are closely correlated to Co, Cr, Cu, Fe, V, Zn, and the pollution load index. In addition, Principal Coordinate Analysis and fuzzy C-means cluster analysis allowed us to make a classification and to perform a magnetic-chemical characterization of the data into four groups, thereby identifying critical (possibly polluted) sites from the Vellar River.     

Geochemical Study of a Granitic Area – The Margeride Mountains, France: Chemical Element Behavior and 87Sr/86Sr Constraints

A small watershed (89 km2) underlain by granite or granite-gneiss in the Margeride mountains, southern Massif Central (France), has been studied using the chemical and isotopic composition of its dissolved load, bed sediments and soils. Dissolved concentrations of major ions (Cl, SO4, NO3, HCO3, Ca, Na, Mg, K, Al and Si), trace elements (Rb and Sr) and strontium isotopes have been determined for three different hydrologic periods in the main stream of the Desges river and its tributaries. The aim was to characterize the chemical and isotopic signatures of each reservoir in the watershed; signature changes are interpreted as fluctuations in the different influencing components: rainwater, weathering products and anthropogenic addition. In the study area, as in other watersheds in granite environments, the only source for input of chemical species into the dissolved load at high altitude is chemical weathering and atmospheric deposition, whereas at lower altitude, human influence plays a non-negligible role. As precipitation is a major vehicle for the addition of dissolved chemical species into the hydrosystem, a systematic rainwater study using an automatic collector was carried out over one year in order to better constrain rain elemental input. Corrections for rainwater addition, using chloride as an atmospheric-input reference, were computed for selected elements and for 87Sr/86Sr ratios. After these correction, the geochemical budget of the watershed was determined and the role of anthropogenic addition was evaluated based on strontium isotope relationships. For particulate matter, we used the normalization of chemical species relative to parent rocks and the element ratios which reflect the depletion or enrichment in soils and sediments. Both the immobile- and mobile-element approaches have been tested, using Ti/Zr and La/Ce ratios for the former and Ca/Sr, K/Rb, and K/Fe ratios for the latter. This revised version was published online in July 2006 with corrections to the Cover Date.     

不同类型沉积物磁化率的比较研究和初步解释

沉积物的磁化率分析以被广泛应用在第四纪古气候研究中,不同类型沉积物磁化率的解释可能存在明显的差异.本文选择了黄土、冲积物、湖积物、风沙堆积和南方红土等五种不同类型的沉积物,进行了磁化率的测试,粒度和孢粉分析,试图通过对沉积物磁化率和相关古环境指标的研究,对不同类型沉积物的磁化率予以对比并进行初步解释.研究结果表明,黄土和湖泊沉积中磁化率的变化主要受气候变化的影响,是指示古气候的重要指标;河流沉积物和风沙沉积物的磁化率主要受粒度的影响;影响南方红土磁化率的因素十分复杂,其磁化率的解释比较困难有待进一步的研究.这一研究表明,鉴于不同沉积物磁化率的影响因素存在明显的不同,因此在运用磁化率进行古环境解释时须持慎重态度.     

Chemical Composition of Urban Street Sediments and Its Sources

INTRODUCTIONBeijingfacesseveredustpollutionduetosuchsourcesasdustimportedfromwesterndeserts,industryandpowerplants,domesticcombustionprocessesandtraffic .Inthelastdecades ,theurbanpopulationhasgrowntomorethan10million .TheeconomicgrowthofChinahasalsoleftitsfootprintsinBeijing .Newindustrialzonesanddomesticar easweredeveloped ,inducinganincreasingtrafficcirculation(Shi,2 0 0 1) .Thedroughtclimateinalmostthewholeyear ,thestrongmonsoonsinwinterbringingdustsfromtheGobidesert,theheavytraffic…     

Mapping of heavy metal loadings in soils by means of magnetic susceptibility measurements

Contamination of soils with heavy metals is an issue all industrial and urban regions have to deal with. Generally, chemical methods are chosen to monitor soil pollution but measurements of magnetic susceptibility proved to yield additional information at low cost and consuming less time. We measured the magnetic susceptibility of soils which had been analysed chemically during the soil surveys of three Austrian provinces. Each anomaly of susceptibility either coincided with geogenic anomalies or indicated anthropogenic input of pollutants. Regional comparisons of susceptibility with chemical analyses revealed that susceptibility can be used as an indicator for the contents of individual pollutants in soils. This calibration of susceptibility has been successfully applied to an industrial region as well as to an urban environment. Two powerful applications of susceptibility measurements of soils are shown: the identification of polluted areas, and the detailed mapping of these areas to reveal the extent of pollution.     

Field and dual magnetic susceptibility proxies for heavy metal pollution assessment in the urban soil of Al-Karak City, South Jordan

A total of 115 urban soil samples collected on grid bases from Al-Karak, South Jordan, were investigated for their field and dual-frequency magnetic susceptibility (χ _field, χ _d) and heavy metal content using Bartington susceptibility meters and ICP-MS. The upper soils have higher magnetic susceptibility values than lower soils, and large particles contain more heavy metals and higher magnetic susceptibility than smaller particles. This might be attributed to the lack of pedogenesis due to arid climate influence. Within the upper soil all heavy metal showed positive significant correlation with upper soil low-frequency χ _dlf. This was evident from the distribution maps produced by Surfer 9.0 for χ _dlf and heavy metals. The results showed that higher χ _dlf is associated with traffic-dominated sites more than other areas. The frequency-dependent susceptibility (χfd %) falls between 2 and 10 %, which indicate the presence of admixture of fine supermagnetic particles. Mildly correlation exists between χfd % and χ _dlf, which implies that soils contain anthropogenic multi-domain grains. Selected samples have been analyzed for their mineral constituents; the results indicate the presence of magnetite as the main magnetic mineral. This confirms the anthropogenic source of pollution mainly from the vehicle-related materials. The results indicate the applicability of magnetic susceptibility for pollution detection.     

长江三峡库区土壤与水系沉积物Cd地球化学特征

对长江三峡库区段不同介质中Cd的分布特征和长江水系沉积物在垂向、横向剖面上的元素分布特征的研究发现，残坡积型土壤与长江干流水系沉积物Cd含量差异较大，水系沉积物具明显的高Cd异常；各个沉积时期的水系沉积物中均存在Cd异常，上游来源的Cd是引起三峡库区水系沉积物高Cd异常的主要因素；人类活动对土壤和水系沉积物中Cd的含量影响明显，在厂矿、码头、生活垃圾场等地区土壤中Cd的含量远高于一般地区土壤中Cd的含量，城市排污水系沉积物Cd的含量也高于长江干流水系沉积物Cd的含量。自然源是沿长江流域Cd异常普遍存在的根本原因，而人为源却有可能是高Cd异常主要沿长江干流及支流两岸大中城市分布的重要影响因素。     

Magnetic properties of river sediments and their relationship with heavy metals and organic matter in the urban area in Lanzhou, China

As the largest industrial city locating in the Northwestern China, Lanzhou has become one of the most seriously polluted cities in the world. In this study, investigations were performed on the magnetic properties, heavy metals and organic matter contents of a total of 23 sediment samples collected from eight selected rivers in the Lanzhou urban area. The results of the study indicate that the magnetic properties of the sediment samples are predominated by low-coercivity magnetite. The river sediments are classified into three types, i.e., downstream polluted, upstream polluted, and less affected, based on the contribution from anthropogenic activities in different segments of the river as indicated by the variation of magnetic mineral concentration parameters. Moreover, a strong linear positive correlation exists among some of the magnetic parameters and organic matter content, heavy metals (Cr, Ni, Pb, Zn, Fe) and total enrichment factor (R) of the bulk deposit samples, which indicates that environmental magnetic technology may be an effective method for distinguishing source apportionment and monitoring river sediment pollution in urban areas.     

Magnetic studies applied to different environments (soils and stream sediments) from a relatively polluted area in Buenos Aires Province,Argentina

Anthropogenic influence, mainly due to urban and industrial activities, may affect fluvial environments and soils, via atmospheric contamination and liquid and solid waste.Continuing previous works on stream sediments and soils, the Gran La Plata area was chosen. In this area, located in the Northeast of Buenos Aires Province (Argentina), several streams and soils were sampled. The streams have similar characteristics, although some of them have a higher input of pollutants (fluvial effluents, fly ashes, solid wastes, etc.). The studied soils have different pedological development.Magnetic and chemical studies were carried out in the laboratory. Analyses of the results indicated that the behavior of magnetic parameters can be related to the variations of heavy metal contents in stream sediments but there is not a good correlation in soils. The comparison between both environments (stream-sediment and soils) reveals a different impact of pollutants. Magnetite, especially PSD grains, seems to be the main carrier for both environments.     

磁学方法在环境污染研究中的应用

环境磁学方法问世20多年来，因其快速、灵敏、经济、无破坏性和信息量大的特点，在环境研究中得到广泛的应用。磁学方法可用于传统的污染分析技术（化学）之前的预研究，而后者一般耗费大量人力、物力和时间；它也可以作为环境污染评估的代用指标。近年来，随着世界环境污染问题的日益严重和倍受关注，磁学方法被广泛地应用于环境污染研究。欧洲环境磁学专家在重建污染历史、监测现代环境污染、追踪与分离污染源等方面，开展了大量的工作，并积累了一定的经验。介绍了磁学方法用于污染研究的显著特点、主要用途、野外工作方法以及相关仪器；展示了在大气、土壤、潮滩、河流、湖泊以及海洋等不同环境系统中，利用磁手段研究污染的成果和最新进展；对 于一些难点、热点问题，如磁性机理的研究、多源污染的分离、强烈多变的人类活动对获取有意义磁讯号的影响等，做了相应的分析和总结。     

Distinguishing between natural and anthropogenic sources of metals entering the Irish Sea

International agreements (e.g. OSPAR) on the release of hazardous substances into the marine environment and environmental assessments of shelf seas require that concentrations and bioavailability of metals from anthropogenic sources can be distinguished from those originating as a result of natural geological processes. The development of a methodology for distinguishing between anthropogenic and natural sources of metals entering the Irish Sea through river inputs is described. The geochemistry of stream, river and estuarine sediments has been used to identify background geochemical signatures, related to geology, and modifications to these signatures by anthropogenic activities. The British Geological Survey (BGS) geochemical database, based on stream sediments from 1 to 2 km² catchments, was used to derive the background signatures. Where mining activity was present, the impact on the signature was estimated by comparison with the geochemistry of sediments from a geologically similar, but mining free, area. River sediment samples taken upstream and downstream of major towns were used respectively to test the validity of using stream sediments to estimate the chemistry of the major river sediment and to provide an indication of the anthropogenic impact related to urban and industrial development. The geochemistry of estuarine sediments from surface samples and cores was then compared with river and offshore sediment chemistry to assess the importance of riverine inputs to the Irish Sea. Studies were undertaken in the Solway, Ribble, Wyre and Mersey estuaries. The results verify that catchment averages of stream sediments and major river samples have comparable chemistry where anthropogenic influences are small. Major urban and industrial (including mining) development causes easily recognised departures from the natural multi-element geochemical signature in river sediment samples downstream of the development and enhanced metal levels are observed in sediments from estuaries with industrial catchments. Stream sediment chemistry coupled with limited river and estuarine sampling provides a cost-effective means of identifying anthropogenic metal inputs to the marine environment. Investigations of field and laboratory protocols to characterise biological impact (bioaccumulation) of metals in sediments of the Irish Sea and its estuaries show that useful assessments can be made by a combination of surveys with bioindicator species such as clams Scrobicularia plana, selective sediment measurements that mimic the ‘biologically available’ fractions, and laboratory (mesocosm) studies.     

湘江入湖河段沉积物重金属污染及其Pb同位素地球化学示踪

湘江是我国重金属污染最严重的河流之一.本次工作利用等离子质谱(ICP-MS)和多接收同位素质谱(MC-ICP-MS)等技术,对湘江入湖河段沉积物进行了系统的重金属微量元素和Pb同位素分析.结果表明,湘江河床沉积物明显富集Bi、Sc、V、Mn、Ni、Cu、Zn、Pb、Cd、Sn、Sb等多种重金属微量元素,而湖盆沉积物重金...     

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).     

Geochemical evidence for diversity of dust sources in the southwestern United States

Several potential dust sources, including generic sources of sparsely vegetated alluvium, playa deposits, and anthropogenic emissions, as well as the area around Owens Lake, California, affect the composition of modern dust in the southwestern United States. A comparison of geochemical analyses of modern and old (a few thousand years) dust with samples of potential local sources suggests that dusts reflect four primary sources: (1) alluvial sediments (represented by Hf, K, Rb, Zr, and rare-earth elements, (2) playas, most of which produce calcareous dust (Sr, associated with Ca), (3) the area of Owens (dry) Lake, a human-induced playa (As, Ba, Li, Pb, Sb, and Sr), and (4) anthropogenic and/or volcanic emissions (As, Cr, Ni, and Sb). A comparison of dust and source samples with previous analyses shows that Owens (dry) Lake and mining wastes from the adjacent Cerro Gordo mining district are the primary sources of As, Ba, Li, and Pb in dusts from Owens Valley. Decreases in dust contents of As, Ba, and Sb with distance from Owens Valley suggest that dust from southern Owens Valley is being transported at least 400 km to the east. Samples of old dust that accumulated before European settlement are distinctly lower in As, Ba, and Sb abundances relative to modern dust, likely due to modern transport of dust from Owens Valley. Thus, southern Owens Valley appears to be an important, geochemically distinct, point source for regional dust in the southwestern United States.     

Impact of metallurgy on the geochemical signature of dusts, soils and sediments in the vicinity of Elbasan complex (Albania)

An investigation of the metallurgical complex surroundings in Elbasani, Albania used background samples to rule out the level of contamination in the study area. Our results show that atmospheric dust particles and soils are of high concern while overbank sediments and actual river sediments are of lower concern. The heavy metals with concentrations of up to 5 times above the local background values are Zn, Cr, Ni, Cu, Fe and Co in soils; Fe, Cr, Co, Ni, Zn, Pb in dust particles; and, Cr and Zn in the actual river/stream sediments. Due to the small size of the dust particles and the atmospheric transportation mechanism primarily related to prevailing winds, the concern for the transport of dust particles is high, especially with respect to risks associated with inhalation. The people working and living in the vicinity of the metallurgical complex of Elbasani are at the highest risk of exposure. Concerns relating to soils are associated with the potential for translocation of the trace element particles into vegetation, in particular, within the upper part of the plants. Therefore, the consumption of the vegetables grown in the vicinity of the metallurgical site should be avoided. Special attention has been given to the Shkumbini river, where the long residence time of water and particulates may result in transitions of trace elements between dissolved and particulate phases downstream.     

Geochemistry of two sediment cores from the west coast of India

Copper, Pb, Zn, Ni, Co, Mn, AI, Ca, magnetic susceptibility and loss on ignition of sediments from two cores near Mangalore along the western continental shelf of India have been studied. The sediments have high Al and organic matter contents due to the high sedimentation rate and their proximity to river mouths. Down-core variations of elements indicate a decrease of lithogenous component during probably the past few centuries. While abundance of calcareous shells in some zones has lead to the dilution of most of the metals, it appears that Pb and Mn are associated with this phase. Copper, Zn and Fe are associated with organic matter and detrital particles, whereas Ni and Co are predominantly associated with the insoluble fraction. Oxides/hydroxides of Fe and Mn are absent because of the reducing conditions and the high terrigenous influx. Geochemically, Mn and Fe are present in different phases of sediments (in the insoluble fraction and organic matter respectively). The Fe content of one of the cores is positively correlated with magnetic susceptibility.