Magnetic particles in indoor dust as marker of pollution emitted by different outside sources

The potential relation between outdoor pollutants and the quality of indoor air was evaluated. A case study was carried out in the small town of Zyrardow situated south-west of Warsaw, Poland. The indoor dust from 20 apartments from several parts of the town that are anticipated to be exposed to various levels of pollution was investigated: a mildly polluted area (suburban), a heating plant area, a post-industrial area and the city center. For evaluation of indoor dust several magnetic parameters (mass-specific magnetic susceptibility χ, its temperature dependence, anhysteretic remanent magnetization, hysteresis loop parameters) were applied. Analysis of magnetic properties was supplemented by analysis of chemical elements: Cd, Cu, Co, Cr, Fe, Mn, Ni, Pb and Zn. Depending on the location of apartments, large variations in concentration, mineralogy and grain-size of magnetic particles were detected. The thermomagnetic analysis revealed magnetite as a primary magnetic phase. In indoor dust, the Curie temperature of ~760°C and soft hysteresis loops with relatively low coercivity values of ~1.5-5 mT are an attribute of metallic iron. The dust collected from apartments located near the local heating plant area, in contaminated post-industrial and suburban areas contains mainly magnetite and only a small amount of metallic iron. Mass-specific magnetic susceptibility is in the range from 40 to 200 × 10^-8 m³kg^-1 and linearly correlates with concentration of individual heavy metals: Ni, Cr, Co and Zn. Magnetic fraction of dust from the city center mainly consists of magnetite and variable amounts of metallic iron. Magnetic susceptibility shows linear correlations with concentration of Fe and concentration of individual heavy metals (Zn, Ni and Co) considered as traffic-related. The study demonstrates that metallic iron present in indoor dust is a potential marker of trafficrelated sources and it makes it possible to use magnetic methods as a tool for evaluation of traffic-related impact on indoor air levels.     

Low-field variation of magnetic susceptibility measured by the KLY-4S Kappabridge and KLF-4A magnetic susceptibility meter: Accuracy and interpretational programme

The KLY-4S Kappabridge and KLF-4A Magnetic Susceptibility Meter enable automated measurement of susceptibility variation with field in the ranges of 2–450 A/m and 5–300 A/m (in effective values), respectively. Unfortunately, the measurement accuracy decreases with decreasing field and it is not easy to decide whether the susceptibility variation at the lowest fields is natural phenomenon or results from measuring errors. To overcome this problem, the accuracies of both the above instruments were investigated experimentally using artificial specimens (mixture of pure magnetite and plaster of Paris) with variable susceptibilities ranging from 1 × 10⁻⁵ to 5 × 10⁻². The complete curve of the field variation of susceptibility of each specimen was measured 10 times and the relative error was calculated for each field. In the KLY-4S Kappabridge, in specimens with susceptibilities higher than 100 × 10⁻⁶, the relative errors are lower than 3% in all fields and lower than 1% in the fields stronger than 10 A/m. In the KLF-4A Magnetic Susceptibility Meter, in relatively strongly magnetic specimens with susceptibilities 5 × 10⁻⁴ to 5 × 10⁻², the relative error is less than 1.5% in the entire field range. While the former instrument is convenient for investigating almost all rock types, the latter instrument is convenient for measuring moderately and strongly magnetic specimens. To facilitate work with field variation of susceptibility curves, showing variable accuracies with field, the programme FieldVar was written. One of its options is plotting the measured data with corresponding field-variable error bars. In this way, a tool is offered for interpreting such susceptibility changes that are sound and reasonable from the point of view of measuring accuracy.     

Strongly magnetic soil developed on a non-magnetic rock basement: A case study from NW Bulgaria

The enhanced magnetic susceptibility of modern soils is assumed to have several reasons including, e.g., weathering of an iron-rich geological basement, natural fires, bacterial processes and atmospheric deposition of anthropogenic particles. We report on a case where none of the above sources of magnetic enhancement is evident: a modern soil with high magnetic susceptibility over the whole soil profile, developed on nonmagnetic limestones, in an area with no industrial activities. The surface magnetic susceptibility varies from 60 to 110×10⁻⁵ SI, while that of the rock basement is nearly zero. Moreover, significant frequency-dependent magnetic susceptibility (> 12%) suggests that superparamagnetic secondary magnetite/maghemite plays an important role. Possible mechanisms, responsible for this magnetic enhancement, are discussed.     

A high-resolution magnetic susceptibility study of a loess/palaeosol couplet at Baoji,China

Summary Magnetic susceptibility, and its frequency dependence, are reported for 288 individual samples spanning the 8.3 m — thick S3 palaeosol/L4 loess couplet at an important site in the Chinese Loess Plateau. The resulting profile demonstrates that there is a very close link between magnetic properties and soil development: soil and loess sub-divisions recognised visually in the field are clearly reflected in both the bulk susceptibility data and in its frequency dependence. As found at all Chinese sites, the distribution of susceptibilities is bi-modal, one peak representing loess (median=0.74×10⁻⁶m³/kg), the other representing palaeosol (median=2.99×10⁻⁶m³/kg). This is the basis of the climatic proxy information. The Baoji section is the site of one of the most detailed grain-size analyses available anywhere (Ding et al., 1994), and we find a strong correlation between the resulting profile and the susceptibility data reported here. Frequency-dependence of susceptibility exhibits slight differences between the loess and palaeosol populations which we interpret as reflecting reduced transport distances during glacial intervals when the Siberian High causes stronger winds and expands southwards.     

Magnetic anomalies and rock magnetism of basalts from Reykjanes (SW-Iceland)

This study presents rock magnetic properties along with magnetic field measurements of different stratigraphic and lithologic basalt units from Reykjanes, the southwestern promontory of the Reykjanes peninsula, where the submarine Reykjanes Ridge passes over into the rift zone of southwestern Iceland. The basaltic fissure eruptions and shield lava of tholeiitic composition (less than 11500 a old) show a high natural remanent magnetization (NRM, J_r) up to 33.6 A/m and high Koenigsberger ratio (Q) up to 52.2 indicating a clear dominance of the NRM compared to the induced part of the magnetization. Pillow basalts and picritic shield lava show distinctly lower J_r values below 10 A/m. Magnetic susceptibility (κ) ranges for all lithologies from 2.5 to 26×10⁻³ SI.     

A combined rock magnetic and geochemical investigation of Upper Cretaceous volcanic rocks in the Pontides,Turkey

Upper Cretaceous volcanic rocks were collected at 24 sites along the Pontides, N-NE Turkey, for rock magnetic and geochemical studies. Rock magnetic and petrographic methods showed that the lavas are characterized predominantly by titanomagnetites with a mixture of pseudo-single and multi-domain grains, whereas in tephrite single domain titanohematite was dominant. Measurements of magnetic susceptibility and the geochemical properties on different volcanic rock types provide important knowledge about the magnetic stability of the rocks. The magnetic properties are interpreted in terms of the composition, concentration, magma generation. Tephrite and phonotephrites with the highest intensities (5200 mA/m) and high magnetic susceptibility values (2585 × 10⁻⁵), largest grain sizes and Fe/Ti values, showing minor or no alteration are the most magnetic stable samples in contrast to dacites with the lowest intensity-magnetic susceptibility (520 mA/m − 573 × 10⁻⁵) and high alteration degree. The basanite samples show very low NRM (48–165 mA/m) but very high magnetic susceptibility (2906–3100 × 10⁻⁵) values suggesting the alteration of Fe-Ti minerals. It is shown that the magnetic properties of the basic to acidic rocks show a systematic variation with magma differentiation and could be related to fractional crystallization. Major and trace elements revealed that the lavas are compatible with complex magma evolution, with mineral phases of olivine+magnetite+clinopyroxene in basic series, amphibole+ +clinopyroxene in intermediate rocks and plagioclase+clinopyroxene+biotite in acidic series.     

Magnetic signature of different vegetation species in polluted environment

Detailed magnetic study on vegetation samples from several strongly polluted and clean sites in Bulgaria is carried out in order to evaluate suitability of different species as passive dust collectors in magnetometry. From each location, available species among lichens, mosses, poplar leaves, dandelion, needles have been sampled. Magnetic susceptibility calculated on mass-specific basis shows wide variability between diamagnetic signal up to 846 × 10⁻⁸ m³/kg. Lichens and mosses are found to be the species, showing magnetic signals with the strongest contrast between clean and polluted environment. The main magnetic phase is magnetite-like according to the results from thermomagnetic analysis of susceptibility on magnetic extracts. Scanning electron microscopy (SEM) microphotographs reveal the presence of abundant particulate matter on vegetation surface both with anthropogenic (spherules) and lithogenic origin. Magnetic grain size deduced by the ratio of saturation remanent magnetization (SIRM) and mass-specific magnetic susceptibility (χ) and coercivities (B_c and B_cr) suggest that different species accumulate preferentially small SD-like grains from pollution emissions. Contrasting relationship of the ratio of anhysteretic remanent magnetization (ARM) and χ for polluted vs clean sites deduced by needles and lichens may be related to transformation of the accumulated dust particles within lichens’ tissue. This finding indicates that the exact species used as biological dust collector is of importance when studying spatial grain size distribution of magnetic dust particles. Pilot study on polycyclic aromatic hydrocarbons (PAH) content and its relation to magnetic parameters shows good correspondence between high levels of PAHs and high SIRM values for locations affected by non-ferrous industrial production.     

杭州城区土壤的磁性与磁性矿物学及其环境意义

对杭州城区四个不同功能区块土壤进行了系统的环境磁学测定,结果表明城市土壤的磁化率平均值为128×10^-8m³·kg^-1,频率磁化率平均值3.6%(样品数=182),城市土壤呈现明显的磁性增强. 城市土壤的磁化率与频率磁化率呈极显著指数负相关,表明城市土壤磁性增强明显区别于自然成土过程引起的以超顺磁性(SP)颗粒为主的表土磁性增强机理. 统计分析表明,城市土壤磁化率与软剩磁和饱和等温剩磁(SIRM)呈显著直线正相关,说明亚铁磁性矿物是城市土壤剩余磁性的主要载体. 综合等温剩磁获得曲线、热磁曲线、磁滞回线等岩石磁学测定和SEM/EDX分析,城市土壤的磁性矿物以磁铁矿和赤铁矿为主,磁性矿物以假单畴-多畴（PSD-MD）颗粒存在,粒度明显大于成土过程形成的磁性颗粒,这些磁性颗粒主要来自燃料燃烧、汽车尾气等环境污染物. 因此,城市土壤磁测可作为城市土壤污染监测、污染空间分布和污染物来源判断的新手段.     

Magnetic survey of topsoils in Windsor–Essex County, Canada

Windsor–Essex County is a major cross-border truck and transportation route, with significant localized industrialization as well as rural and farming areas. Magnetic property measurements (in-field and laboratory susceptibility, frequency-dependent susceptibility, hysteresis properties, thermomagnetic and thermosusceptibility curves, anhysteretic and isothermal magnetizations) were made in order to determine the potential for using such variables to distinguish between natural and anthropogenic pollutants. In-field magnetic susceptibility measured on 324 soil sampling sites on a 0.5–2 km grid spacing through Windsor–Essex County ranged from 3.7 × 10^− 6 to 305.2 × 10^− 6 SI (average 36.2 ± 35.8 × 10^− 6 SI), and showed that high magnetic susceptibility values were obtained on soil sampling sites in and around the cities/towns of Windsor, Harrow, Olinda and Oakland and near the beaches of Point Pelee National Park (PPNP) and Deerbrook, whereas lower susceptibility values were observed in near the towns of Lakeshore and Essex. On this grid spacing, Highway 401 (the major truck route) did not show anomalous susceptibility values; however, closer (1–3 m) sampling on other roads did show anomalously high values, suggesting that the coarser grid spacing may have missed anomalies. Laboratory measurements indicated that the dominant magnetic mineral in the Windsor–Essex County soils is magnetite; however, the grain size is variable. Pseudo-single domain (PSD)–multidomain (MD) magnetite is generally found on beaches and in PPNP, whereas single domain (SD)–PSD magnetite has been found near the City of Windsor and other towns. While certain correlations exist between some anthropogenic activities and the measured magnetic susceptibility and magnetic property values, no overall correlation can be made. A variety of geologic and anthropogenic factors must be considered when interpreting the origin of the magnetic signal in a particular area.     

Carriers of magnetism and vertical inhomogeneities in ultramafic-mafic rocks of the Kondyor Massif (Aldan shield)

Dunite samples from a borehole drilled in the platiniferous concentrically-zoned Kondyor Massif are studied by electron spin resonance (ESR). The spectrum profiles, relative intensities I, and volume magnetic susceptibilities κ are analyzed. These values experience strong irregular variations, sometimes by an order of magnitude, in the upper and medium parts of the column, at depths from 100 to 400 m; and the variations decay at greater depths. The magnetic properties of the samples are determined by iron (II) ions in the olivine lattice and by iron (III) ions in the magnetite and pyrrhotite microphases and in the products of breakdown of the solid solution: chromiferous magnetite, chromoferrite, etc. The I and κ values are directly related: κ_max = 27.8 × 10⁻³ SI units, κ_min=2.63 × 10⁻³ SI units, and κ_mean = 12.7 × 10⁻³ SI units. The maximum κ values are found in the zones with elevated contents of magnetite and pyrrhotite particles, and the minimum ones, in zones with few medium and small clusters with Fe³⁺ ions. The uneven distributions of solid solutions and magnetic phases over depths are suggested to be related to the disturbances in the conditions of crystallization.     

Magnetic survey of topsoils in Windsor–Essex County,Canada

Windsor–Essex County is a major cross-border truck and transportation route, with significant localized industrialization as well as rural and farming areas. Magnetic property measurements (in-field and laboratory susceptibility, frequency-dependent susceptibility, hysteresis properties, thermomagnetic and thermosusceptibility curves, anhysteretic and isothermal magnetizations) were made in order to determine the potential for using such variables to distinguish between natural and anthropogenic pollutants. In-field magnetic susceptibility measured on 324 soil sampling sites on a 0.5–2 km grid spacing through Windsor–Essex County ranged from 3.7 × 10^− 6 to 305.2 × 10^− 6 SI (average 36.2 ± 35.8 × 10^− 6 SI), and showed that high magnetic susceptibility values were obtained on soil sampling sites in and around the cities/towns of Windsor, Harrow, Olinda and Oakland and near the beaches of Point Pelee National Park (PPNP) and Deerbrook, whereas lower susceptibility values were observed in near the towns of Lakeshore and Essex. On this grid spacing, Highway 401 (the major truck route) did not show anomalous susceptibility values; however, closer (1–3 m) sampling on other roads did show anomalously high values, suggesting that the coarser grid spacing may have missed anomalies. Laboratory measurements indicated that the dominant magnetic mineral in the Windsor–Essex County soils is magnetite; however, the grain size is variable. Pseudo-single domain (PSD)–multidomain (MD) magnetite is generally found on beaches and in PPNP, whereas single domain (SD)–PSD magnetite has been found near the City of Windsor and other towns. While certain correlations exist between some anthropogenic activities and the measured magnetic susceptibility and magnetic property values, no overall correlation can be made. A variety of geologic and anthropogenic factors must be considered when interpreting the origin of the magnetic signal in a particular area.     

北京市朝阳区大气降尘磁学特征及对空气污染物浓度的指示

应用环境磁学方法研究了2008年奥运会前后北京市朝阳区大气降尘及对照点表土样品的磁学特征.结果表明,所有样品中载磁矿物主要为低矫顽力的亚铁磁性矿物(主要为磁铁矿).但大气降尘样品的磁性颗粒粒度较表土偏粗;磁性矿物含量高于表土样品,大气降尘除来自于自然源外,更多为来自于人为因素的结果.大气降尘磁化率与空气污染物浓度随时间...     

Ten-antenna prototype of a radio heliograph based on the Siberian Solar Radio Telescope

An upgrade of the Siberian Solar Radio Telescope (SSRT) [Smolkov et al., 1986; Grechnev et al., 2003] to a multiwave radio heliograph has been started. The radio heliograph being created will be designed mainly to measure coronal magnetic fields, to determine the locations of solar-flare energy release, and to investigate coronal mass ejections. These tasks define the parameters of next-generation radio heliographs. A high spatial resolution, a high image acquisition rate, and a high sensitivity are required simultaneously. All these parameters should be realized in the widest possible frequency range—from fractions to tens of GHz). The expected parameters of the future SSRT-based radio heliograph are listed below: spatial resolution 12″–24″, temporal resolution 0.02–1.0 s, frequency range 4–8 GHz, sensitivity up to 100 K, left-hand and right-hand circular polarizations, data rate 0.5–20 Mb s⁻¹ (normal and flare modes). In this paper, we describe the broadband antennas, analog optical data transmission lines, and correlator used in the 10-antenna radio heliograph prototype.     

Bathing water quality monitoring of Varna Black Sea coastal zone,Bulgaria

Physicochemical and microbiological characteristics of the bathing waters in Varna’s Black Sea coastal area were investigated during year 2007 at 23 monitoring stations. Most of the determined physicochemical parameters—pH, mineral oils, surface active substances, phenols, dissolved oxygen, nutrients and microbiological parameters—“Total coliforms”, “Faecal coliforms”, “Faecal streptococci” were in compliance with the guidline’ limits and exhibited good water quality. Ammonium and phosphate’s pollution above the limits was determined at the South beach, Officers beach and Central beach situated in Varna’s central bathing zone. For the period of 13.08 to 24.10.2007—70% of the South beach samples analyzed for NH₄⁺ exceeded the limits 60 times and the concentrations of PO₄³⁻ exceeded the limits 17.5 times. Some deviations from the guidline’ limits regarding the microbiology were exhibited at the same beaches. A conclusion is made that the area of study is not yet seriously threatened, in spite of the rapid recreation during the last years.     

Thermal structure and heat loss at the summit crater of an active lava dome

Forward-Looking Infrared (FLIR) nighttime thermal images were used to extract the thermal and morphological properties for the surface of a blocky-to-rubbley lava mass active within the summit crater of the Caliente vent at Santiaguito lava dome (Guatemala). Thermally the crater was characterized by three concentric regions: a hot outer annulus of loose fine material at 150–400°C, an inner cold annulus of blocky lava at 40–80°C, and a warm central core at 100–200°C comprising younger, hotter lava. Intermittent explosions resulted in thermal renewal of some surfaces, mostly across the outer annulus where loose, fine, fill material was ejected to expose hotter, underlying, material. Surface heat flux densities (radiative + free convection) were dominated by losses from the outer annulus (0.3–1.5 × 10⁴  s⁻¹m⁻²), followed by the hot central core (0.1–0.4 × 10⁴ J s⁻¹m⁻²) and cold annulus (0.04–0.1 × 10⁴ J s⁻¹m⁻²). Overall surface power output was also dominated by the outer annulus region (31–176 MJ s⁻¹), but the cold annulus contributed equal power (2.41–7.07 MJ s⁻¹) as the hot central core (2.68–6.92 MJ s⁻¹) due to its greater area. Cooled surfaces (i.e. the upper thermal boundary layer separating surface temperatures from underlying material at magmatic temperatures) across the central core and cold annulus had estimated thicknesses, based on simple conductive model, of 0.3–2.2 and 1.5–4.3 m. The stability of the thermal structure through time and between explosions indicates that it is linked to a deeper structural control likely comprising a central massive plug, feeding lava flow from the SW rim of the crater, surrounded by an arcuate, marginal fracture zone through which heat and mass can preferentially flow.     

Rheology of the lower crust beneath the northern part of North China: Inferences from lower crustal xenoliths from Hannuoba basalts, Hebei Province, China

Lower crustal xenoliths brought up rapidly by basaltic magma onto the earth surface may provide di-rect information on the lower crust. The main purpose of this research is to gain an insight into the rheology of the lower crust through the detailed study of lower crustal xenoliths collected from the Hannuoba basalt, North China. The lower crustal xenoliths in this area consist mainly of two pyroxene granulite, garnet granulite, and light-colored granulite, with a few exception of felsic granulite. The equilibration temperature and pressure of these xenoliths are estimated by using geothermometers and geobarometers suitable for lower crustal xenoliths. The obtained results show that the equilibration temperature of these xenoliths is within the range of 785―900℃, and the equilibrium pressure is within the range of 0.8―1.2 GPa, corresponding to a depth range of 28―42 km. These results have been used to modify the previously constructed lower crust-upper mantle geotherm for the studied area. The dif-ferential stress during the deformation process of the lower crustal xenoliths is estimated by using recrystallized grain-size paleo-piezometer to be in the range of 14―20 MPa. Comparing the available steady state flow laws for lower crustal rocks, it is confirmed that the flow law proposed by Wilks et al. in 1990 is applicable to the lower crustal xenoliths studied in this paper. The strain rate of the lower crust estimated by using this flow law is within the range of 10-13―10-11 s-1, higher than the strain rate of the upper mantle estimated previously for the studied area (10-17―10-13 s-1); the equivalent viscosity is estimated to be within the range of 1017―1019Pa·s, lower than that of the upper mantle (1019―1021 Pa·s). The constructed rheological profiles of the lower crust indicate that the differential stress shows no significant linear relation with depth, while the strain rate increases with depth and equivalent vis-cosity decrease with depth. The results support the viewpoint of weak lower continental crust.     

Monitoring and forecasting nitrate concentration in the groundwater using statistical process control and time series analysis: a case study

Contaminated water resources have important implications on health and the environment. Nitrate contamination of the groundwater is a serious problem in the European Union. A method based on the statistical process control (SPC) and time series analysis is developed to monitoring and to predict the concentration evolution of nitrate (NO₃ ⁻) in groundwater. In many pumping wells the NO₃ ⁻concentration ([NO₃ ⁻]) increases and approaches or even passes the European Community standard of 50 mg l⁻¹. The objective of this paper is to show the application of statistical process control as a monitoring tool for groundwater pollution from agricultural practices. We propose the autoregressive integrated moving average (ARIMA) model as a management tool to monitoring and reduction of the intrusion of nitrate into the groundwater. This tool should help in setting up useful guidelines for evaluating actual environmental performance against the firm’s environmental objectives and targets and regulatory requirements. We concluded that the statistical process control method may be a potentially important way of monitoring groundwater quality that also permits rapid response to serious increases in pollutants concentrations. In doing so, the paper fills an important gap in the water pollution standards and emerging polices (Water Framework directives).     

Magnetic Susceptibility and Heavy Metals Distribution from Risk‐cultivated Soil around the Iron–Steel Plant,China

Magnetic susceptibility is a non‐conventional way that can be used for evaluating proxy soil heavy metals pollution. The paper monitors available heavy metals (Cu, Fe, Zn, and Mn) present in cultivated soils around iron–steel plant by soil magnetic susceptibility. Our study was located in an area with high pollution with small grid density of 250 m in China. Results showed that low field magnetic susceptibility was significantly correlated with available Cu, Zn, and Mn. No clear association exists between magnetic susceptibility and available Fe, soil organic matter, pH. Frequency dependent susceptibility >5% suggests the possible presence of super‐paramagnetic particles, fly ashes produced during coal combustion.     

The carbon isotope composition of C<Superscript>3</Superscript> herbaceous plants in loess area of northern China

¹³C of 367 C₃ herbaceous plants was measured in loess area in northern China. Their δ¹³C values vary between −21.7%. and −30.0%., with a mean of −26.7%.. In the center of Loess Plateau (semimoist area) with annual precipitation of 400–600 mm, the δ¹³ C values of C₃ herbaceous plants range from −24.4%. to −28.5%., with a mean of −27.5%.. In the west of Loess Plateau (semiarid and arid area) with annual precipitation less than 400 mm, they range between −21.7%. and −30.0%., with a mean of −26.2%.. Annual precipitation is the main factor that makes δ¹³C values of C₃ herbaceous plants in the west greater than those in the central Loess Plateau. The composition of δ¹³C in C₃ plants increases with deceasing annual precipitation, and the mean change is −49%./100 mm.     

The mechanism of regional gravity changes before and after the Tangshan earthquake

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