Using robust kriging and sequential Gaussian simulation to delineate the copper- and lead-contaminated areas of a rapidly industrialized city in Yangtze River Delta,China

A total of 540 topsoil samples (0–15 cm), 188 subsoil samples (20–40 cm), and four individual soil profiles were collected in this study for mapping the Cu- and Pb-contaminated areas in soils of Zhangjiagang city, an industrialized city in the Yangtze River Delta region of China. Robust geostatistical methods were applied for identifying possible spatial outliers of Cu and Pb data, and then a sequential Gaussian simulation was employed for delineating the potential areas where Cu or Pb concentration was affected by diffuse pollution. The results showed that the spatial outliers of Cu and Pb were strongly associated with various types of factories. The anthropogenic input of Cu to soils at local hotspots was closely related to emissions of printing and dyeing, metallurgical, and chemical factories, whereas a lead oxide factory and a chemical factory resulted in a considerable increase of Pb in the topsoil of the study area. Approximately 30% of the total land area of the study was at potential risk from the Cu or Pb diffuse pollution resulting from rapid industrialization of the area over the past 20 years.     

Polycyclic aromatic hydrocarbon concentrations in urban soils representing different land use categories in Shanghai

An extensive soil survey was carried out in Shanghai to investigate the spatial distribution and possible sources of polycyclic aromatic hydrocarbons (PAHs) in urban soils. Soil samples were collected from highways, iron-smelting plants, steel-smelting plants, shipbuilding yards, coking plants, power plants, chemical plants, urban parks, university campuses and residential areas and were analyzed for 16 PAHs by gas chromatography with mass detection. High PAH concentrations were found in all locations investigated, with mean values of soil total PAH concentrations in the range 3,279–38,868 μg/kg DM, and the PAH concentrations were significantly influenced by soil organic matter content. Soil PAH profiles in all districts were dominated by PAHs with 4–6 rings. Principal components analysis and diagnostic ratios of PAHs indicate that they were mainly derived from coal combustion and petroleum but in soils from highways the PAHs were derived largely from vehicle exhaust emissions. The high concentrations of PAHs found indicate that many urban soils in Shanghai represent a potential hazard to public health.     

Spatial distribution, source identification and affecting factors of heavy metals contamination in urban–suburban soils of Lishui city, China

An investigation on spatial distribution, possible pollution sources, and affecting factors of heavy metals in the urban–suburban soils of Lishui city (China) was conducted using geographic information system (GIS) technique and multivariate statistics. The results indicated that the topsoils in urban and suburban areas were enriched with metals, such as Cd, Cu, Pb, and Zn. Spatial distribution maps of heavy metal contents, based on geostatistical analysis and GIS mapping, indicated that Cd, Cr, Cu, Mn, Ni, Pb, and Zn had similar patterns of spatial distribution. Their hot-spot areas were mainly concentrated in the densely populated old urban area of the city. Multivariate statistical analysis (correlation analysis, principal component analysis, and clustering analysis) showed distinctly different associations among the studied metals, suggesting that Cr, Cu, Ni, Pb, Cd, and Zn had anthropogenic sources, whereas Co and V were associated with parent materials and therefore had natural sources. The Cd, Cr, Ni, Pb, and Zn contents were positively correlated with soil organic matter, pH, and sand content (p < 0.01). It is concluded that GIS and multivariate statistical methods can be used to identify hot-spot areas and potential sources of heavy metals, and assess soil environment quality in urban–suburban areas.     

Application of spatial analysis and multivariate analysis techniques in distribution and source study of polycyclic aromatic hydrocarbons in the topsoil of Beijing,China

Surface soil samples were collected from 161 sites throughout the downtown and suburban area of Beijing, China. The samples were analyzed for polycyclic aromatic hydrocarbons (PAHs) concentrations. Through Kriging analysis, five heavily contaminated zones were identified in the study area. Sources of PAHs in the soil were apportioned using principal factor analysis and multiple linear regression. Three factors were identified representing coal combustion/vehicle emission, coking emission, and petroleum sources, respectively. The relative contributions of the three sources were 48% for coal/vehicle emission, 28% for coking emission, and 24% for petroleum sources. The contributions of total PAHs from the three sources were 16.4, 4.63 and 3.70 ng g⁻¹, respectively. Spatial analysis indicated that the contribution of coal/vehicle sources was higher in the downtown area than in the suburban area, the petroleum sources had a high contribution in the urban area, and the contribution of coking sources was high in the suburban area. The results indicated that PAH contamination in the surface soil in Beijing was closely related to the spatial characteristics of energy consumption and functional zoning. Improvement of the energy consumption structure and relocation of industries with heavy pollution are effective ways to control PAH contamination in surface soil in the area.     

Investigation of spatial variability and pattern analysis of soil properties in the northwest of Iran

Analysis of the spatial variability of soil properties is important to explain the site-specific ecosystems. Spatial patterns of some soil properties such as soil texture, exchangeable sodium percentage (ESP), electrical conductivity (ECe), soil pH and cation exchange capacity (CEC) were analyzed in salt and sodic affected soils in the south of the Ardabil province, in the northwest of Iran, to identify their spatial distribution for performance of a site-specific management. Soil samples were collected from 0 to 30, 30 to 60, 60 to 90, 90 to 120 and 120 to 150 cm soil depths at sampling sites. Data were investigated both statistically and geostatistically on the basis of the semivariogram. The spatial distribution model and spatial dependence level varied in the study area. Among the considered parameters, maximum and minimum spatial variability were observed in EC and pH parameters, respectively. Soil properties showed moderate to strong spatial dependence, except for a few. ECe was strongly spatially dependent in the total soil depth and clay was strongly spatially dependent at the first depth. Sand and pH were moderately spatially dependent for three of the five depths. ESP was strongly spatially dependent and silt was moderate in the total soil depths, except at 90–120 cm depth. Furthermore, CEC had strong spatial dependence for three of the five depths. All geostatistical range values were >1,389 m in this study. It was concluded that the strong spatial dependency of soil properties would lead to extrinsic factors such as bedrock, agricultural pollution, drainage and ground water level.     

北京市表层土壤中PAHs含量特征及来源分析

土壤,作为城市中最重要的环境介质,承担了较高多环芳烃(PAHs)的环境负荷,开展土壤PAHs分布特征及来源分析研究,可以为污染风险防控、环保政策制定提供支撑.为研究北京市不同功能区土壤环境中PAHs的含量、组成及来源,本文在北京市主城区进行了大范围采样,同时针对工业区、农业种植区、水源保护区及居民区等不同功能区进行了分...     

Soil contamination by toxic metals in the cultivated region of Agia, Thessaly, Greece. Identification of sources of contamination

A soil geochemical survey was undertaken in the cultivated region of Agia in Thessaly area, Central Greece. The objectives of the study were to assess the levels of soil contamination in respect to average concentrations of toxic metals in the region, to determine the associations between the different toxic elements and their spatial distribution and to identify possible sources of contamination that can explain the spatial patterns of soil pollution in the area. One hundred seventy three soil samples were collected and analysed by ICP-AES after digestion with a mixture of HClO₄–HNO₃–H₂O. The study focused on eleven elements (Cu, Pb, Zn, Ni, Co, Mn, As, V, Cr, Fe and Mg) and all of them except Pb have mean concentrations above the average global soil composition. The elements Ni, Cr, Mn and V show concentrations that according to G.L.C guidelines the Agia soils are classified as slightly contaminated to contaminated. Factor analysis explained 84.02% of the total variance of the data through four factors. Combined with spatial interpretation of its output, the method successfully grouped the elements according to their sources and provided evidence about their natural or anthropogenic origin.     

北京市土壤中Cr,Ni含量的空间结构与分布特征

本文以一个完整的省级行政单元(北京市)为例,进行系统的、大尺度的土壤Cr,Ni含量的空间分布与污染评价研究,通过地统计学方法分析揭示了北京市土壤中Cr,Ni的空间结构与分布特征,并探索其主要成因,为全面了解北京市的土壤环境质量和开展大规模的土壤环境质量评价研究等提供方法学借鉴和参考.结果表明:土壤Cr,Ni含量的空间结构具有较好的可迁性特点;指数模型拟合效果较好,变程分别为174.6km和15km;半变异函数的方向性分析表明,Cr,Ni均为各向同性,土壤中Cr,Ni具有中等程度的空间相关性.土壤中Cr含量的分布特征为空间相关范围较大,从总体趋势来看,土壤Cr含量的分布较为连续,呈明显的东高西低的分布趋势,大致可以分为3个大的斑块,西北方向(太行山山脉)土壤Cr含量较低,而东南方向(冲积平原)土壤Cr含量相对居中,东北部(燕山山脉)的土壤Cr含量最高.土壤Ni含量的空间分布比较零散,其分布大致表现为东北部地区最高,西南部居中,中部地区最低.研究还揭示,北京市土壤中Cr,Ni含量目前仍主要受成土母质的影响,但是个别地区也存在明显的Cr,Ni含量严重偏高现象.     

Spatial variability of soil organic matter and nutrients in paddy fields at various scales in southeast China

The present study examines the spatial dependency of soil organic matter and nutrients in paddy fields at three different scales using geostatistics and geographic information system techniques (GIS). The spatial variability of soil organic matter (SOM), total nitrogen (TN) and available phosphorus (AP) has been characterized using a total of 460, 131 and 64 samples that were, respectively, collected from the Hangzhou–Jiaxing–Huzhou (HJH) Plain (10 km), Pinghu county (1,000 m) and a test plot area (100 m) within the Pinghu county, Zhejiang province of the southeast China. Semivariograms showed that the SOM and TN had moderate spatial dependency on the large scale of HJH plain and moderate scale of Pinghu county with long spatial correlation distances. At the moderate scale of Pinghu county and the small scale of a test plot area, the AP data did not show any spatial correlation, but had moderate spatial dependency in HJH plain. Spherical and exponential variogram models were best fitted to all these soil properties. Maps of SOM and TN were generated through interpolation of measured values by ordinary kriging, and AP by lognormal kriging. This study suggests that precision management of SOM and TN is feasible at all scales, and precision management of AP is feasible at large scales.     

Studies on the chromium concentrations in topsoils and subsoils of two rapidly industrialized cities in the Yangtze River Delta in east China

A total of 782 topsoil samples (0–20 cm) and 371 subsoil samples (20–40 cm) were collected from agricultural land in two rapidly industrialized areas with a large number of small rural industries in southeast China, Zhangjiagang City (ZJG) and Changshu City (CS), to measure soil chromium (Cr) concentrations. Kriging and cokriging were used to predict the spatial distribution of Cr in the topsoils and subsoils. Paired-samples t test and spatial distribution maps were used to compare the Cr concentrations in topsoils and subsoils. The mean Cr concentration in ZJG topsoils was significantly higher than that in ZJG subsoils and the mean Cr concentration in CS topsoils showed no significant difference from that in CS subsoils. The Cr concentrations in topsoils were higher than those in subsoils over most of the area of ZJG and part of CS, suggesting that Cr accumulation had occurred in these areas and extrinsic factors have an important role controlling the distribution of Cr in topsoils. Semivariogram/cross-semivariogram was used to evaluate soil Cr spatial variability. The Cr in ZJG topsoils, ZJG subsoils, and CS topsoils had moderate spatial dependence and the Cr in CS subsoils had strong spatial dependence. Cr in ZJG subsoils had longer effective range than Cr in ZJG topsoils, suggesting that the anthropogenic factors affecting Cr distribution in ZJG topsoils; and Cr in CS topsoils had longer effective range than Cr in CS subsoils, indicating that soil formation may be the major explanation for the decrease in the variation of Cr in topsoils. A significant correlation was found between the Cr in topsoils and Cr in subsoils, indicating that natural factors also play an important role as extrinsic factors that control the distribution of Cr in topsoils.     

Spatial variability of soil available Zn and Cu in paddy rice fields of China

As a source of nutrient supplements, the deficiency or excess of micronutrients in soil is directly connected to the plant uptake and, thereby, status of micronutrients in the human population. Proper management of micronutrients requires an understanding of the variations of soil micronutrients across the fields. This study is to investigate the spatial patterns of soil available Zn and Cu in paddy rice fields. Four hundred and sixty three soil samples were taken in Hangzhou–Jiaxing–Huzhou (HJH) watershed in Zhejiang Province, China, and available Zn and Cu were analyzed using an atomic adsorption spectrometer. Geostatistical semivariograms analysis indicated that the available Zn and Cu were best fitted to a spherical model with a range of 40.5 and 210.4 km, respectively. There were moderate spatial dependences for Zn and Cu over a long distance and the dependence were attributed to soil types and anthropogenic activities. The overlay analysis of spatial patterns and soil types gave us greater understanding about how intrinsic factors affect the spatial variation of available micronutrients. Based on the above, macroscopically regionalized management of soil available micronutrients and the implications to potential risk were discussed.     

Geochemistry characteristics and evaluation of the pollution extent of arsenic in wastewater irrigated soil in the North of Tianjin City

Based on sampling depths, the research environment of the soil in a study area is divided into two parts: the I environment (I-E) and the II environment (II-E). The results of the statistical analysis of arsenic (As) in the soil of the I-E indicates that the statistical characteristic value obey a normal distribution. The mean value of As is close to the world mean value, China and Tianjin City. Also, the contrast between the spatial change characteristics of As of the I-E and the II-E soils showed that the I-E resembles the II-E in the content variety of As. On the other hand, geochemistry methods were applied in the estimation of contaminated extent. The results indicated that the contamination extent of the north of Tianjin City has not been serious. __________ Translated from Geological Bulletin of China, 2007, 26(11): 1486–1493 [译自: 地质通报]     

北京市延庆区土壤重金属元素地球化学特征及其来源分析

北京市延庆区是首都生态涵养区,开展土壤重金属分布特征及来源解析研究对保障土地安全利用、防控生态环境风险具有重要意义。采集延庆区2 354件表层土样及44件深层土样,测试分析了重金属元素As、Cd、Cr、Hg、Ni、Pb、V、Zn及Sc等含量。采用空间分布分析、多元统计分析与受体模型相结合的方法,阐明了土壤重金属元素分布特征,解析了土壤重金属潜在来源,并计算了不同来源对土壤重金属的相对贡献率。结果表明,表层土壤中V、Cr、Ni、As元素主要来源于成土母质,Cd、Zn、Pb含量高值区集中分布于人口密集区域,人为活动对该3种元素影响较大,而Hg主要受大气干湿沉降的影响。深层土壤中Hg元素在居民区含量较高,而其余元素均未受到人为活动的影响。     

Urban expanding pattern and soil organic, inorganic carbon distribution in Shanghai, China

Soil carbon stock changes induced by land-use change play an essential role in the global greenhouse effect and carbon circulation. This paper studies the urban expanding patterns and spatial characteristics of soil organic carbon (SOC) and soil inorganic carbon (SIC) distribution and evolution during the urbanization process of Shanghai, China, based on the data of the regional geochemical survey. Urbanization process in Shanghai, China, has been quickening greatly since the 1980s. The urban area expanded from 193.08 km² in 1980 to 1,570.52 km² in 2005, or up from 3.05 to 24.77% in the past 25 years, and the urban expansion circled the central city region according to the RS images acquired in the periods of 1980, 2000 and 2005. The urban topsoil is slightly enriched with SOC and SIC, which shows obvious spatial variability. By comparison of SOC and SIC distribution in the central urban area, urbanized area during 1980–2000, 2000–2005 and the suburban area, the SOC obviously accumulates in the central urban area, while SOC density in the urbanized area decreases; similarly, the SIC obviously accumulates in central urban area; furthermore, the SIC density increases with urban land use duration extending and urban ecosystem evolving. This paper provides the characteristics of SOC and SIC distribution and evolution during the course of urbanization, which may be useful for assessing the impact of land use and urban development on SOC and SIC pools in urban ecosystem.     

Erosion rates evaluated by the <Superscript>137</Superscript>Cs technique in the high altitude area of the Qinghai–Tibet plateau of China

Studying spatial and temporal variation of soil loss is of great importance because of global environmental concerns. Understanding the spatial distribution of soil erosion and deposition in the high-cold steppe is important for designing soil and water conservation measures. Measured ¹³⁷Cs losses (Bq m⁻²) from long-term high altitude (4,000 m above sea level) watershed plots on the Qinghai–Tibet plateau and derived soil erosion estimates (Mg ha⁻¹ year⁻¹) were significantly correlated to directly measured soil losses from the same plots, over the same period (1963–2005). The local reference inventory was estimated to be 2,468 Bq m⁻². The result of analyzing ¹³⁷Cs distribution and its intensity in the soil profiles in this area shows similarities to ¹³⁷Cs distribution in other areas. ¹³⁷Cs is basically distributed in the topsoil layer of 0–0.3 m. Soil erosions vary greatly in the entire sampled area, ranging from 5.5 to 23 Mg ha⁻¹ year⁻¹, with an average of 16.5 Mg ha⁻¹ year⁻¹ which is a moderate rate of erosion.     

Spatial variability of soil moisture at typical alpine meadow and steppe sites in the Qinghai-Tibetan Plateau permafrost region

Permafrost degradation has the potential to significantly change soil moisture. The objective of this study was to assess the variability of soil moisture in a permafrost region using geostatistical techniques. The experiment was conducted in August 2008 in alpine steppe and meadow located in the Qinghai-Tibetan Plateau permafrost region. Four soil depths (0–10, 10–20, 20–30 and 30–40 cm) were analyzed using frequency domain reflectometry, and sampling made of 80 points in a 10 m × 10 m grid were sampled. Soil moisture was analyzed using classical statistics to appropriately describe central tendency and dispersion, and then using geostatistics to describe spatial variability. Classical statistical method indicated that soil moisture in the permafrost region had a normal distribution pattern. Mean surface soil moisture in alpine meadow was higher than that in alpine steppe. The semivariograms showed that soil moisture variability in alpine cold steppe was larger than that in alpine meadow, which decreased with depths. Nugget values in alpine steppe were low (0.1–4.5), in contrast to alpine cold meadow. Soil moisture in alpine steppe had highly structured spatial variability with more than 93.4% spatial heterogeneity, and the range decreased with depth. Soil moisture content in alpine cold meadow had a moderate spatial dependence with a range of 51.3–169.2 m, increasing with depth.     

Spatial variability of soil nutrients in disturbed riverine mangrove forests at different stages of regeneration in the San Juan River estuary,Venezuela

Geostatistical analysis of selected soil properties were performed in two mangrove sites (B7 and B9) dominated by the mangrove speciesRhizophora mangle along the San Juan River, Venezuela, to evaluate the effect of forest disturbance on nutrient spatial distributions. Plots within area B7 were clear-cut in 1972–1973 and in area B9 in 1982–1983. Four plots within each area were systematically selected and represented natural (2) and regenerated (2) forests. Individual plots were 1.5 ha in B7 and 1.25 ha in B9 and sampled at a resolution of 25 m. Soil samples were obtained at the intersection of an aligned grid with 90 points in B7 and 78 points in B9. Measured soil properties included salinity, total nitrogen, total carbon, total phosphorus, osmolality, and pore water cation concentrations (potassium, calcium, magnesium, and sodium). Sites were sampled in May 1996 and 1997, although spatial analysis was performed only for the data obtained in May 1997. Geostatistical analysis showed that most of the variables tested were spatially auto-correlated within each area and that there were no differences between regenerated and natural plots. Structural variance as a proportion of sample variance ranged from 55–99% for most of the properties. The significant spatial dependence observed for most of the variables in natural and regenerated plots, despite management schedules, indicates that clear-cutting did not have an effect on modifying the distribution of nutrient concentrations. These results suggest that after 15 and 25 yr following forest disturbance nutrient distributions were reestablished either there was not a net effect on patterns of element loss or tidal input was stronger than plant modifications of soils.     

环渤海低平原水土盐分与水位埋深的空间变异及协同克立格估值

针对环渤海低平原水土盐分和水位埋深,通过选取0～20cm深度内的127个代表性土样进行土壤全盐量测定,并对130个水井的水位埋深及128个地下水样的矿化度进行测定.综合运用普通克立格(OrdinaryKriging)与协同克立格(CoKriging)方法与GIS技术研究水土盐分及水位埋深的空间分布状况.结果表明,土壤盐...     

北京通州某改造区土壤中PAHs的来源分析及风险评价

近些年,随着我国城市化进程不断加快,土壤中多环芳烃污染已经成为威胁土壤环境质量和人体健康的主要因素。文章采集了北京市通州某改造区15件表层土壤（0~20 cm）样品,利用GC-MS分析技术,研究了土壤中美国环境保护署（USEPA）优控的16种多环芳烃（PAHs）的含量及组分特征,根据多环芳烃的空间分布特征和特定成分之间的浓度比值结合多元统计法分析了其污染来源,初步评价了其污染水平,并进行健康风险评价。结果表明:表层土壤中16种多环芳烃含量范围为6.57~8 307.2 μg/kg,均值为1 004.08 μg/kg。多环芳烃组分特征及Fla与（Fla+Pyr）、BaA与(BaA+Chr)的相对质量比值特征显示改造区是燃煤和汽车尾气混合型来源;多元统计后发现石油烃类污染源和化石燃料燃烧源是两种主要成分。最后参照《污染场地风险评估技术导则（HJ 25.3—2014）》对土壤中PAHs进行了健康风险评价,除苯并（a）芘（BaP）致癌风险值略偏高不可接受外,其余致癌与非致癌风险值均可接受。     

Compositional fractionation of polyaromatic hydrocarbons in the karst soils, South China

This study aims to explore the condensation and fractionation trends of persistent organic pollutants (POPs) in the karst soils. The tiankeng is a karst surface expression that can act as a focal point for introduction of contaminants to a karst aquifer, which may serve both as condenser for vapor phase POPs and as barrier/sink for particulate associated less volatile POPs. The fractionation of POPs in soils from the upper rim and floor of tiankeng is of interest in understanding the role of tiankeng in the long-distance transport of POPs. In the present study, polycyclic aromatic hydrocarbons (PAHs) in the surface soils from the upper rim and floor of Dashiwei tiankeng in Southern China were analyzed. The total PAH concentrations in soils were 23.40–190 ng g⁻¹, with phenanthrene being the most abundant. The distribution patterns of PAH compounds in the soil samples matched well with their properties. It indicated the heavy PAHs were susceptible to retention by the floor soils of tiankeng than light PAHs. A plot of Cfloor/Crim against PAH molecular weight gave a good positive relationship in the molecular weight range of 152–276. It is suggested that the floor soils can be focal points of more concentrated PAH and deserve attention. The concentrations of total PAHs in the floor soils (43.40–190 ng g⁻¹, mean 87.76 ng g⁻¹) were higher than those in the upper rim (23.40–88.94 ng g⁻¹, mean 57.74 ng g⁻¹). In addition, there was a shift in compound pattern with an increase in the proportion of light PAHs (2–3 rings), a decrease in heavy PAHs (5–6 rings) and a relatively stable content of 4-ring PAHs. A combination of particulate scavenging and cold condensation is proposed as the major mechanism for the compositional fractionation of PAHs in the soils from the upper rim and floor of tiankeng.