Application of magnetic susceptibility and heavy metal bioaccessibility to assessments of urban sandstorm contamination and health risks: Case studies from Dunhuang and Lanzhou, Northwest China.

Direct ingestion of sandstorm particles is an important pathway in human exposure to heavy metals. This study investigated the potential health risks of heavy metals transported in sandstorms from Dunhuang to Lanzhou in northwestern China using environmental magnetic parameters and metal bioaccessibilities in simulated gastric and intestinal tracts. The mean magnetic susceptibility of sandstorms in Lanzhou was 366.

Pollution monitoring using the leaf-deposited particulates and magnetism of the leaves of 23 plant species in a semi-arid city, Northwest China.

We conducted a study of the leaf-deposited particles and magnetism of plant leaves in different functional areas (traffic areas, parks, and residential areas) in Lanzhou, China. The saturation isothermal remanent magnetization (SIRM) of the washed and unwashed leaves of 23 plant species (including evergreen shrubs, deciduous shrubs, deciduous liana species, and deciduous trees) at three sampling heights (0.5 m, 1.

Holocene dust storm variations over northern China: transition from a natural forcing to an anthropogenic forcing.

Asian dust storms have long been a major environmental concern in China, affecting the lives of about one billion people. However, it is unclear whether the mechanisms responsible for Asian dust storms during the Holocene varied on different timescales, and thus it is unclear whether there was a shift from a natural forcing to an anthropogenic forcing of dust storms. We reconstructed a high-resolution Holocene record of dust storms from the sediments of an undisturbed alpine lake on the Chinese Loess Plateau.

The influence of roadside trees on the diffusion of road traffic pollutants and their magnetic characteristics in a typical semi-arid urban area of Northwest China.

Leaf samples of Juniperus formosana were collected from an open road environment, in order to establish how particulate matter (PM) generated by vehicles was dispersed in both horizontal and vertical directions. Sampling was conducted at sites with trees of varying height and configuration adjacent to a major road in Lanzhou, Gansu Province, Northwest China. The concentration of remanence-bearing ferrimagnets in the leaf samples was estimated from measurements of Saturation Isothermal Remanent Magnetization (SIRM), while the weight of particles deposited on the leaves and their elemental composition were determined at different heights and in different directions relative to the road.

Magnetic characteristics of Juniperus formosana needles along an urban street in Lanzhou, Northwest China: the variation of different season and orientation.

The magnetic properties of particulate matter (PM) deposited on the needles of Juniperus formosana along an urban street in Lanzhou city were measured to evaluate the variations of PM concentration in different seasons by varying distance from the road. The magnetism of PM deposited in this context was significantly higher in winter than in summer, which may reflect changes of atmospheric particle concentrations. Needle samples which were collected from the road-facing side exhibiting significantly stronger magnetism compared with those which were collected from the opposite side of the road, indicating the distance from pollution source to the needles as a factor controls the amount of PM.

[Magnetic Properties of Farmland Soils in Arid Regions in Northwest China and Their Environmental Implications].

In order to understand the feasibility of environmental magnetism methods in farmland soil pollution monitoring in the northwest arid areas of China, the environmental magnetic properties of 102 farmland soil samples from four typical agricultural regions, namely Linze county, Ganzhou district, Minle county, and Shandan county in Zhangye City were systematically analyzed. The results show that the main magnetic mineral of farmland soil samples is ferrimagnetic magnetite, and the main magnetic grain sizes are coarse-grained pseudo single domain (PSD) and multidomain (MD), mainly between 0.2-1 μm in equivalent diameter.

Source apportionment of soil-contamination in Baotou City (North China) based on a combined magnetic and geochemical approach.

We studied the magnetic properties and trace element concentrations (Cr, Cu, Fe, Mn, Pb, Ti, V, Zn) of urban topsoils from 111 urban sites in a large REE-Nb-Fe mining and smelting city, Baotou, Inner Mongolia, China. The results show that pseudo-single domain and multi-domain magnetite dominates the magnetic properties of the soil samples, and the magnetic concentration parameters show a large positive anomaly near the Baotou iron and steel works. The average contents of all trace metals exceeded their background level in soils in Inner Mongolia, except for Pb.

[Magnetic Characteristics and Environmental Pollution Analysis of Street Dust in Different Functional Zones of Xi'an City].

Urban environmental pollution can be revealed by the magnetic characteristics of street dust. Environmental magnetic measurements were carried out for the 151 samples of street dust collected in different functional zones of Xi'an city. Magnetic susceptibility varied within the range between 169.

[Spatial Distribution of Stable Isotope from the Lakes in Typical Temperate Glacier Region].

We focused mainly on the spatial variation and influencing factors of hydrogen and oxygen stable isotopes between water samples collected at the surface and different depths in the Lashi Lake in August, 2014. Hydrological supply characteristics of the lake in typical temperate glacier region were discussed. The results showed that the values of δ¹⁸O and δD in the Lashi Lake ranged from -12.

[Pollution Characteristics and Source Apportionment of PM₂.₅, in Lanzhou City].

In order to understand the characteristics and sources of PM₂.₅ pollutant in Lanzhou City, two PM₂.₅ sampling sites were set up in Chengguan district and Xigu district, respectively.

[Magnetic Responses of Heavy Metals in Street Dust of Typical Mine-Based City, Northwest China].

Magnetic characteristics and heavy metal properties of 43 street dust samples collected from Baiyin City, northwest of China were systematically analyzed. The results revealed that the main magnetic minerals were low-coercivity magnetite and maghemite with coarse pseudo single domain (PSD) and multi-domain (MD) in magnetic grain size. Compared with the domestic comprehensive cities, low frequency magnetic susceptibility(χlf) value of street dust samples in Binyin varied from 43.

Detecting the sensitivity of magnetic response on different pollution sources--A case study from typical mining cities in northwestern China.

Rapid monitoring and discriminating different anthropogenic pollution is a key scientific issue. To detect the applicability and sensitivity of magnetic measurements for evaluating different industrial pollution in urban environment, characteristics of topsoil from three typical fast developing industrial cities (Jinchang, Baiyin and Jiayuguan in Gansu province, northwestern China) were studied by magnetic and geochemical analyses. The results showed that magnetic susceptibility was enhanced near industrial areas, and PSD-MD magnetite dominated the magnetic properties.

Urban particle size distributions during two contrasting dust events originating from Taklimakan and Gobi Deserts.

The dust origins of the two events were identified using HYSPLIT trajectory model and MODIS and CALIPSO satellite data to understand the particle size distribution during two contrasting dust events originated from Taklimakan and Gobi deserts. The supermicron particles significantly increased during the dust events. The dust event from Gobi desert affected significantly on the particles larger than 2.

[Spatial Distribution of Magnetic Properties of Street Dust in Baoji City and Its Implications of Environment].

Magnetic characteristics of street dust can reflect important information of environmental conditions. Environmental magnetic measurements were carried out on the samples of street dust in Baoji City. The results indicated a high concentration of magnetic minerals in street dust, dominated by multiple domain (MD) and pseudo-single domain (PSD) ferrimagnetic minerals which were mainly from the traffic and industrial pollution.

Combination of magnetic parameters and heavy metals to discriminate soil-contamination sources in Yinchuan--a typical oasis city of Northwestern China.

Various industrial processes and vehicular traffic result in harmful emissions containing both magnetic minerals and heavy metals. In this study, we investigated the levels of magnetic and heavy metal contamination of topsoils from Yinchuan city in northwestern China. The results demonstrate that magnetic mineral assemblages in the topsoil are dominated by pseudo-single domain (PSD) and multi-domain (MD) magnetite.

[Magnetic properties of topsoils in typical industrial belt along the Yellow River in arid regions in northwest China and their environmental significance].

We have carried out environmental magnetic investigation on topsoil samples of two industrial cities Wuhai and Shizuishan along the Yellow River in the arid regions in northwest China. The concentration, type, magnetic grain sizes of the magnetic minerals and the environmental significance were discussed. The results showed that the main magnetic grain sizes were multi-domain (MD) and pseudo single domain (PSD).

Detection and differentiation of pollution in urban surface soils using magnetic properties in arid and semi-arid regions of northwestern China.

Increasing urbanization and industrialization over the world has caused many social and environmental problems, one of which drawing particular concern is the soil pollution and its ecological degradation. In this study, the efficiency of magnetic methods for detecting and discriminating contaminates in the arid and semi-arid regions of northwestern China was investigated. Topsoil samples from six typical cities (i.

[Magnetic property of dustfall in a Northwest China valley city and its environmental implications].

Lanzhou is one of the seriously polluted cities in Northwest China. Dustfall samples collected in Lanzhou and the countryside Huanghuatan were studied using magnetic methods. The results reveal that the content of magnetic mineral in dustfall samples from Lanzhou is much higher than that of Huanghuatan.

[Characteristics of heavy metal elements and their relationship with magnetic properties of river sediment from urban area in Lanzhou].

The contents of As, Co, Cr, Cu, Ni, Pb, V and Zn in the surface sediments from 8 rivers in urban area in Lanzhou were monitored by ecological risk which was assessed by the potential ecological Håkanson index, and the index of geoaccumulation (Igeo), sediment enrichment factor (R), and environmental magnetism. The results showed that: (1) the potential ecological risk of heavy metals of As, Co, Ni, V in surface sediments from 8 rivers were low, which belonged to low ecological risk. But the risk of heave metals Cr, Pb, Zn in surface sediments from Yuer river was high, which belonged to middle ecological risk, and in downstream of Yuer river, the element of Cu belonged to high ecological risk.

[Magnetic characters of river sediment of urban area in Lanzhou].

A total of 23 deposits samples were collected from 8 selected the river sediments in Lanzhou urban area as researching objects of magnetic property and organic matter measure. The results indicate that: (1) the magnetic property controlled by magnetite which is ferrimagnetic mineral, and anti-ferromagnetic component such as hematite and goethite; (2) the value of samples' magnetic parameters (such as: chi, SIRM, magnetic hysteresis loops and M-T curves) increased from upstream to downstream in Paihong River, Shier River and Yuer River, Shuimo River; decreased in Qili River and Lanni River; and contrasting above-mentioned, the value of samples' magnetic parameters were low in Luoguo River and Dasha River. Based on the variation of magnetic parameters, such as chiFD, chiARM, chiFD/Ms and chiARM/Ms, we divided the rivers into three groups according to the contribution originating from anthropogenic activities into spatial river sediments: first type, such as Paihong River, Shier River, Yuer River and Shuimo River, called downstream concentrate type; second type, such as Qili River and Lanni River, called upstream concentrate type; third type, such as Luoguo River and Dasha River, called less affected type.

[Analysis of particulate pollution characteristics and its causes in Lanzhou, Northwest China].

Seasonal characteristics, annual variations and trend of PM10 and the causes of the PM10 long-term trend in Lanzhou were studied for the period of 2001-2007 using daily air pollution index (API) data and detrending technique. Results indicate that air quality in Lanzhou has been improved since 2001. The annual averaged PM10 concentration decreased from 236 microg x m(-3) in 2001 to 127 microg x m(-3) in 2007 and the number of days satisfying the Chinese Grade I and II air quality standard increased 2.

[Correlations between leaf delta13C and physiological parameters of desert plant Reaumuria soongorica].

Reaumuria soongorica is a dominant species in the desert shrubbery vegetation in arid regions of northwestern China, playing an important role in the maintenance of the stability and continuity of desert ecosystem. In this paper, a total of 407 individuals in 21 natural populations of R. soongorica were selected from its main distribution areas to measure the leaf stable carbon isotope composition (delta13C) and nitrogen, phosphorus, potassium, water, proline and chlorophyll contents, with the correlations between the delta13C value and the test physiological parameters analyzed.

[Magnetic characteristics of street dust in Lanzhou and its environmental significance].

Lanzhou has been one of the most seriously polluted cities in the world due to its special geographical location and weather conditions, which make it an ideal place for urban pollution studies. A set of environmental magnetic parameters (chi lf, chi fd%, chi ARM, chi HIRM, SOFT and back field IRM) of the street dust sampled in Lanzhou during spring and summer 2005 were analyzed. These samples were collected along a main street across the urban area and a mountain route from foot to the top.