黄河三角洲表层土壤重金属空间分布与潜在生态风险评价

研究黄河三角洲表层土壤中重金属空间分布特征,评价其潜在生态风险。结果表明:表层土壤(0-20 cm)Cu、Zn、Cr、Cd、Pb、Ni、As和Hg的平均含量为27.87,79.19,69.01,0.383,21.98,33.42,13.76,0.025 mg/kg。除Cd外,其他重金属含量平均值均小于国家二级标准值;各重金属空间分布均呈现自西北向东南递减的趋势,且实验区含量最高,核心区含量最小;Hakanson潜在生态风险指数评价表明,Cd为中等-较强生态危害,其余重金属单项均为轻微生态危害,潜在风险程度由高到低依次为Cd>Hg>As>Ni>Cu>Pb>Cr>Zn;保护区综合潜在生态风险为轻微-中等生态危害,呈实验区>缓冲区>核心区的规律。重金属受人类活动影响较大,距离人类活动较近区域含量高,较远区域含量低。     

天山北坡土壤重金属含量的分布特征及其来源解释

以天山北坡巴里坤 伊吾、新源 巴音布鲁克和昭苏 特克斯3个区段为研究区域, 利用新疆土壤背景值、土壤环境质量二级标准(GB15618-1995)、单因子污染指数法和内梅罗综合污染指数法对不同区段土壤重金属含量进行污染评价, 应用多元统计分析方法对不同区段之间的土壤重金属含量及其污染指数进行定量比较, 分析并阐明不同区段土壤重金属含量的分布特征及其污染来源。结果表明: 天山北坡巴里坤 伊吾区段各重金属(Cr、Cu、Ni、Pb、Zn)含量的平均值及其单因子污染指数和综合污染指数比新源 巴音布鲁克区段、昭苏 特克斯区段高, 新源 巴音布鲁克区段的比昭苏 特克斯区段高。巴里坤 伊吾区段土壤重金属污染程度比新源 巴音布鲁克区段、昭苏 特克斯区段高, 新源 巴音布鲁克区段的比昭苏 特克斯区段高。巴里坤 伊吾区段重金属污染除了受成土母质的影响之外, 还受人为因子(交通、工业和农业、旅游业)的影响, 其中PC1方差贡献率为91.22%; 新源 巴音布鲁克区段土壤重金属污染除了受成土母质的影响之外, 还受人为因子(交通和工业)的影响, 其中PC1方差贡献率为67.58%, PC2贡献率为22.47%; 昭苏 特克斯区段土壤重金属污染主要受成土母质的影响, 此外该区段的农业对其也有一定影响, 其中PC1方差贡献率为47.93%, PC2方差贡献率为29.84%。     

喀纳斯景区土壤重金属污染及其潜在生态风险评价

[目的]对喀纳斯景区土壤重金属污染及其潜在生态风险进行评价,为景区资源科学管理和保护提供参考依据。[方法]以喀纳斯景区为研究区,测定土壤样品As,Pb,Hg,Cd,Zn,Cr,和Cu含量,通过污染负荷指数对喀纳斯景区重金属污染情况进行全面评价,采用潜在生态风险指数法对土壤重金属进行潜在生态风险评价,并运用相关分析与主成分分析法对土壤重金属来源与污染程度进行深入分析。[结果](1)研究区表层土壤As,Pb,Hg,Cd,Zn,Cr和Cu平均含量分别为6.48,16.60,0.10,0.08,84.71,2.47,32.23mg/kg,其中As,Pb,Hg和Cd高于新疆土壤背景值,Zn,Cr和Cu低于新疆土壤背景值。(2)人类活动扰动强由强至弱4个样地,7种重金属含量不同,且同一重金属在4个样地间具有一定差异性。(3)人类活动扰动强样地、人类活动扰动较强样地和人类活动扰动轻微样地3个样地中Hg为重度污染(PLI值分别为5.70,4.36,4.64),Zn,Cr,Cu为轻度污染。全部金属RI均小于150,研究区仅存在轻微生态危害,但研究区Hg污染需关注。(4)7种重金属间大多存在关系,Pb与Hg,Cd和Zn呈显著相关(p≤0.01)。Cd和Hg来源相同可能性较大,As,Zn和Cu来源可能一致。[结论]喀纳斯景区受旅游活动干扰土壤中重金属有不同程度的积累,土壤重金属污染愈加严重。     

伊犁河流域土壤重金属含量空间分布及其环境现状研究

以新疆伊犁河流域地区作为研究区域,在对研究区域典型土壤样品中重金属元素Cu、Pb、As、Hg的含量分析基础上,运用GIS地统计学知识分析研究区域土壤Cu、Pb、As、Hg含量的空间分布特征.结果显示:土壤中Cu、Pb、As含量都明显高于新疆土壤背景值,而Hg含量则是显著低于新疆土壤背景值,各元素在研究区域土壤中均表现出不同程度的变异性,其中土壤中As含量的变异程度最大;通过空间分析发现,土壤中Cu、As、Hg含量均表现出中等程度空间相关性,其空间分布受随机因子和结构因子的双重影响,其中土壤As含量受随机因子的影响最大,而土壤Pb含量表现出强烈的空间相关性,主要受结构因子影响.采用内梅罗指数评价法对土壤Cu、Pb、As、Hg含量进行环境污染评价,评价结果显示,土壤Hg尚未受到污染;土壤Cu、Pb属于中度污染,局部地区属于轻度污染;土壤As属于重度污染,其中霍城县、伊宁县、伊宁市、察布查尔县污染现象极为严重.     

某再生铅工业园周边土壤重金属的空间分布及来源分析

基于表层土壤重金属的实测含量,运用多元统计和地统计相结合的方法,对某再生铅工业园周边土壤重金属的分布情况和来源进行分析。结果表明,再生铅工业园周边土壤中Pb、Cd、As、Cr、Cu、Ni、Zn的几何平均含量分别为124.05、0.394、21.18、82.72、24.23、35.47、62.04 mg/kg。其中Pb、Cd、As分别是背景值的4.96、2.90、1.84倍,其余重金属元素含量与土壤背景值相当。重金属Pb、Cd在临近工业园区域含量较大,以工业园为中心呈岛状空间分布,且在工业园东部呈扩散趋势;As在周边农田中具有一定的累积量。来源分析表明,土壤中Pb、Cd主要受工业园生产活动的影响,而As则可能受到农业生产活动的影响。     

空间分析在土壤重金属污染研究中的应用

空间分析技术是土壤重金属污染研究中的一个重要工具。与经典数据统计分析方法学相比,空间分析考虑了数据的空间位置和空间关联性,能挖掘土壤重金属在二维甚至三维空间上的空间分异和时空变异特征,并对这些结果进行可视化使之以更加直观的形式呈现出来。本文概述了探索性空间数据分析(ESDA)、空间回归分析、地统计学及空间插值分析、空间随机模拟等主要空间分析理论和方法。在此基础上,综述了空间分析在土壤重金属污染调查采样设计、空间统计分析、空间变异分析及制图、土壤重金属污染来源解析及污染不确定性研究等方面的应用和研究动态,介绍了一些应用于土壤重金属污染研究的空间分析新方法,并就空间分析方法在土壤重金属研究中的应用前景和发展趋势做了展望。     

城市边缘带土壤重金属空间变异及其污染评价

为揭示城市边缘带强烈人为活动对土壤环境质量的影响，本研究以上海梅山钢铁集团附近14km^2区域为研究区，网格化精确布点，采集表层土壤样品计93个并对其重金属Cu、Zn、Pb、Cr、Cd、Hg、As含量进行了测定分析。结果表明，研究区表层土壤中除Hg和Cd外的其他5种重金属含量均未超过国家二级标准，其中有些土壤中重金属含量接近或略高于南京市土壤环境背景值，但与研究区表层土壤元素地球化学背景值平均水平及空间变异特征基本相符；研究区表层土壤中Hg污染严重，61．3％的样点土壤Hg含量超过国家二级标准。另外，本研究应用地统计学普通克里格插值方法，对研究区内表层土壤污染的空间变异特征进行了分析，并讨论了土壤污染重点空间区域潜在污染源及其污染途径。     

夏尔希里地区土壤重金属含量特征及空间变异分析

以夏尔希里地区为研究区,对土壤样品中Co,Cr,Cu,Mn,Ni共5种重金属的含量特征和空间分异规律进行了研究,采用单因子和内罗梅法分析土壤重金属的污染程度,并利用地统计学方法分析研究区土壤重金属的空间分异特征等。结果表明:研究区5种土壤重金属含量为:Mn > Cr > Cu > Ni > Co,5种重金属和有机质均属于中等变异强度;相关性分析结果显示:Co与Cu,Mn呈现显著相关;Cr与Cu,Ni有显著正相关;有机质与Cr,Mn,Cu,Ni均呈现正相关;重金属含量空间分异特征整体表现为绿洲区 > 荒漠区 > 山地森林区;重金属污染评价结果为:Co和Mn属于轻污染,Cr和Ni处于警戒线,属于尚清洁状态。     

蔬菜产地土壤重金属含量空间分布研究

以浙江省湖州市长兴县为例,应用GIS技术研究了蔬菜产区土壤重金属污染状况及空间分布规律。结果表明:长兴县蔬菜产地平均土壤汞和镉含量明显大于本地背景值,锌平均含量也超过背景值,而砷、铬、铅、铜4种重金属的平均含量则低于或接近背景值。长兴县大部分蔬菜产区土壤重金属含量在国家无公害蔬菜基地标准以下,汞、镉超标的样点分别占总样点的10.4%和4.5%,分别有43%和58.0%的样点超过当地汞、镉背景值,土壤汞、镉含量的最大值分别达到945.85 ng/g和478.88 ng/g。蔬菜产区土壤汞、镉污染呈明显的区域空间分布特征,且与乡镇工业区分布相一致,表明工业污染是引起蔬菜产区土壤重金属超标的主要原因。在长兴县部分地区还存在铬、锌、铜区域性积累趋势。     

黄骅市土壤重金属空间变异特征及污染评价

为研究工业和经济高速发展对环渤海滨海生态脆弱区土壤质量的影响,以黄骅市为研究区,利用地统计学方法对黄骅市表层土壤中的Pb,Hg,Cd,Cr,As,Cu,Zn,Ni共8种重金属空间分布特点和污染状况进行了分析。结果表明:（1）Pb,Cd,Cu元素样点平均含量超过河北省土壤背景值,其他元素含量平均值均未超过,所有元素含量平均值都在国家土壤质量二级标准的范围内。（2）根据变异函数拟合发现,Pb,Hg,Cd,Cr,As,Cu共6种元素拟合于指数模型,Zn,Ni两种元素拟合于球状模型;Pb,Cd,Zn基底效应值为25%～75%,空间自相关程度一般,其空间分布格局受到一定外界干扰。其他元素基底效应值均在25%以下,空间自相关性比较强,空间分布格局受外部影响相对较小。（3）根据克里格内插预测发现,Pb,Cd,Cu整体含量高,区域离散分布;Cr,Zn,Ni整体含量低,连续集中分布;As元素成岛状分布,分布集中于几个区域;Hg成散点状分布于黄骅全县。（4）通过计算内梅罗污染指数可知,黄骅市土壤内梅罗污染指数大部分处于1.0～2.0,属于轻度污染状态;吕桥镇中部和齐家务乡西部污染指数最高,属于污染最严重的地区。工业生产和地质环境是影响土壤重金属元素空间分布的主要原因。     

Accumulation and potential sources of heavy metals in soils of the Hetao area, Inner Mongolia, China

Soil contamination by heavy metals is a problem in agricultural irrigation systems.To assess the accumulation and sources of heavy metals in the Yongji irrigation district of the Hetao area,Inner Mongolia,China,195 soil samples from 39 sites(0–100 cm)were collected,and Zn,Cu,Pb,Cr,and Cd concentrations were analyzed.The mean concentrations were 107.17,32.48,12.31,53.53,and 0.22 mg kg-1,respectively,with no significant differences between soil depths(P>0.05).Concentrations of Zn,Cu,and Cd were higher than the background levels,with moderate accumulation;the contamination factor(CF)values were 1.9,1.7,and 1.9,respectively,and the geoaccumulation index(Igeo)was>0.Concentrations of Pb and Cr were lower than,or close to,the background levels(CF<1,Igeo<0),indicating that they originated from a natural source.The monomial potential ecological risk index(Eri)for Zn,Cu,Pb,and Cr was low;Eri for Cd was 55.73,implying a moderate risk.The grade of potential ecological risk index of the five heavy metals(RI)was low,declining from south to north.The studied soils were contaminated with Zn,Cu,and Cd;principal component(PC)analysis implicated the enrichment of Cd and partial Cu(high loading in PC 2)was related to agricultural activities;Zn and partial Cu,closely associated with PC 3,may have originated from irrigation water from the Yellow River.Future agricultural development should focus on fertilizer and pesticide application and the quality of irrigation water.     

陕西泾惠渠灌区土壤重金属空间分布特征及来源

土壤重金属空间变异性是监测和评价农田生态系统环境质量的前提。该文基于104个表层土壤样品的重金属实测含量,运用多元统计和地统计相结合的方法,对陕西泾惠渠灌区土壤重金属含量的分布特征和来源进行了分析。结果表明,土壤中Hg、As、Cd、Cr、Pb、Cu、Zn、Ni 8种重金属平均质量分数分别为0.091、15.40、0.25、75.50、27.20、28.10、81.10、36.60 mg/kg,均超出土壤背景值(参考1986年报道的陕西省关中平原主要农业土壤中重金属含量),但低于国家土壤环境质量二级标准(GB15618-1995)。地统计分析表明,Hg、Ni、As基底效应介于25%~75%之间,属于中等空间相关;而Zn、Pb、Cd、Cu、Cr基底效应均大于75%,属于空间弱相关。多元统计分析表明,泾惠渠灌区土壤中Cd、Pb、Zn、Cu、As、Cr和Ni的累积主要源于农业生产活动、交通运输等人为活动,而Hg的累积则主要受工业排废的影响。目前,该灌区土壤环境质量良好,但土壤重金属有累积的倾向,应引起重视。     

矾矿千秋史 造福满人间

  目的  本研究从微生物（哈茨木霉菌）钝化与小白菜 (Brassica rapa L.Chinensis Group.）萃取重金属联合修复入手,结合配施有机肥,探究哈茨木霉菌和有机肥复配强化植物萃取修复强酸性重金属污染土壤的效果及机理。  方法  基于盆栽实验,设计哈茨木霉菌钝化与小白菜萃取单独修复及混合修复处理,同时配施有机肥,另设置空白对照,各处理设置3次重复,共计24组处理。  结果  与对照处理相比,哈茨木霉菌和有机肥处理下,土壤pH增加14.05% ~ 34.60%,有机质含量增加10.11% ~ 99.42%;哈茨木霉菌处理下,土壤速效钾和铵态氮含量分别提高51.02%和10.31%;有机肥处理下,土壤有效磷和速效钾含量分别增加451.84%和433.69%。哈茨木霉菌和有机肥复配下小白菜地上部分生物量较对照增加414.29%;小白菜地上生物量与土壤全镉（Cd）呈显著负相关,小白菜地上富集系数及转运系数较对照分别增大25.58%和21.29%;同时土壤全Cd含量降低43.83%,土壤酸可提取态Cd含量降低87.41%,小白菜地上及根系Cd均与土壤酸可提取态Cd呈显著负相关。  结论  本研究显示哈茨木霉菌和有机肥复配具有强化植物萃取重金属效率和对酸性Cd污染土壤修复的潜力,对于矿区重金属污染土壤的植物修复治理提供了理论依据和技术支撑。     

伊朗中部伊斯法罕地区土地利用对石灰性土壤磁性质和重金属的空间分布的影响

Anthropogenic activities have caused the accumulation of heavy metals in the soil environment. Pollution of the soils significantly reduces environmental quality and affects human health. In many recent studies, magnetic susceptibility measurements have been used for pollution monitoring. The objective of this research was to determine the spatial variability of magnetic properties and selected heavy metals and the effects of land use on their variability in the surface soils of the Isfahan region, Central Iran. A total of 158 composite surface (0-5 cm) samples of calcareous soils were collected from an area of about 700 km2, located along a cross-border transect from Isfahan City to a steel plant, covering urban, industrial, agricultural and uncultivated land uses. Concentrations of copper (Cu), zinc (Zn), lead (Pb), manganese (Mn), iron (Fe), nickel (Ni), chromium (Cr), and cobalt (Co) and magnetic parameters, magnetic susceptibility at low frequency (χlf), natural remanent magnetization (NRM), saturation isothermal remanent magnetization (SIRM), and isothermal remanent magnetization at the field of 100 mT (IRM100mT) and the backfield of 100 mT (IRM-100mT), were measured in all the soil samples. Results showed that magnetic susceptibility in the urban and industrial land topsoils (0--5 cm) samples was significantly higher than that in the agricultural and uncultivated land soils in the study area. Concentrations of Cu, Zn, Pb, Mn, and Fe were positively correlated with magnetic properties (χlf, IRM100mT, SIRM, IRM-100mT, and NRM), which could be attributed to their inputs from traffic emissions and industrial activities at the study sites. Ni and Cr concentrations showed significant negative correlations with magnetic properties. No significant correlation was found between Co concentration and magnetic parameters. The Tomlinson pollution load index (PLI) showed significant correlation with the magnetic properties (χlf, IRM100mT, SIRM, IRM-100mT, and NRM). The spatial distribution of the selected heavy metals and χlf in the study area suggested that activities at the urban and industrial land sites caused greater pollution as compared to that at the study sites of other land uses. The concentrations of Cu and Zn seemed to have been affected by anthropogenic sources, whereas Ni, Cr, and Co were mainly controlled by natural sources in the study area. Moreover, the concentrations of soil Pb and Fe in the study area could be affected by both lithologic and anthropogenic sources. The magnetic parameters appeared to be a proxy measure for the degree of heavy metal contamination and could be a potential method for the detection and mapping of contaminated soils.     

人类活动对太湖地区地表水水质的影响

Taihu Lake region is one of the most industrialized areas in China, and the surface water is progressively susceptible to anthropogenic pollution. The physicochemical parameters of surface water quality were determined at 20 sampling sites in Taihu Lake region, China in spring, summer, autumn, and winter seasons of 2005-2006 to assess the effect of human activities on the surface water quality. Principal component analysis (PCA) and cluster analysis (CA) were used to identify characteristics of the water quality in the studied water bodies. PCA extracted the first three principal components (PCs), explaining 80.84% of the total variance of the raw data. Especially, PC1 (38.91%) was associated with NH₄-N, total N, soluble reactive phosphorus, and total P. PC2 (22.70%) was characterized by NO₃-N and temperature. PC3 (19.23%) was mainly associated with pH and dissolved organic carbon. CA showed that streams were influenced by urban residential subsistence and livestock farming contributed significantly to PC1 throughout the year. The streams influenced by farmland runoff contributed most to PC2 in spring and winter compared with other streams. PC3 was affected mainly by aquiculture in spring, rural residential subsistence in summer, and livestock farming in fall and winter seasons. Further analyses showed that farmlands contributed significantly to nitrogen pollution of Taihu Lake, while urban residential subsistence and livestock farming also polluted water quality of Taihu Lake in rainy season. The results would be helpful for the authorities to take sound actions for an effective management of water quality in Taihu Lake region.     

工业型城乡交错区土壤重金属含量及其空间分异的特征-以无锡典型城乡交错区为例

Phosphorus （P） is necessary for growth and nitrogen fixation, and thus its deficiency is a major factor limiting legume production in most agricultural soils. The effect of phosphorus supply on nodule development and its role in soybeans （Glycine max L.） was studied in a nutrient solution. Plants were inoculated with Bradyrhizobium japonicum and grown for 35 days in a glasshouse at a day and night temperature of 25℃ and 15℃, respectively. Although increasing P supply increased the concentrations of P and N in the shoots and roots, the external P supply did not significantly affect the P concentration in the nodules, and the N fixed per unit nodule biomass decreased with increasing P supply. The nitrogen content in the shoots correlated well with the P content （r=0.92＊＊）. At an inoculation level of 10^2 cells mL^-1, the P supply did not affect the number of nodules; however, at inoculation levels of 10^3.5 and 10^5 cells mL^-1, increasing P supply increased both the number and size of nodules. Irrespective of the inoculation level, increasing P supply increased the nodule biomass relative to the biomass of the host plant. It is suggested that the P deficiency specifically inhibited the nodule development and thereby the total N2 fixation.     

榆林市脆弱生态空间分异特征及脆弱度分析

生态环境的脆弱性是自然因素和人为因素共同作用的结果。采用干旱指数、人口集中指数、系统熵等指标与方法,对榆林市的气候、人口、经济以及人均水资源等脆弱因子的空间分异特征进行定量分析研究。结果表明,榆林市的干旱指数由东向西逐渐增大,为半湿润半干旱型气候;人口分布趋于均匀并继续分散;经济发展不平衡,主要集聚在神木县、榆阳区和府谷县;人均水资源西多东少并且整体上逐年减少。基于统计资料,建立评价指标体系,结合主成分分析法和聚类分析法,构建数学模型计算脆弱度并进行等级划分。分析表明,将榆林市生态脆弱性划分为五个等级,脆弱度以榆阳区为中心向四周减弱。     

Distribution Assessment and Source Identification Using Multivariate Statistical Analyses and Artificial Neutral Networks for Trace Elements in Agricultural Soils in Xinzhou of Shanxi Province, China

Multivariate statistical analyses were used to assess the contents and distributions of trace elements in agricultural soils in Xinzhou of Shanxi Province, China, and to identify their sources. Samples with high levels of trace elements were concentrated in eastern Xinzhou, with contents declining from the east to west. Principal component and redundancy analyses revealed strong correlations among Co, Cu, Mn, Ni, Se, V, and Zn contents, suggesting that these elements were derived from similar parent materials. There were also strong correlations between the contents of these elements and soil properties. Contents of Cd and Pb were significantly higher in the agricultural soil samples than in the background soil samples (P < 0.05), and were higher in areas with higher levels of gross domestic product but decreased with distance to the nearest road. Therefore, human activities appear to have a strong influence on the Cd and Pb distribution patterns. A novel artificial neural network (ANN) model, using environmental input data, was used to predict the soil Cd and Pb contents of specified test dates. The performances of the ANN model and a traditional multilinear model were compared. The ANN model could successfully predict Cd and Pb content distributions, projecting that soil Cd and Pb contents will increase by 128% and 25%, respectively, by 2020. The results thus indicated that the economic condition of an area has a greater effect on trace element contents and distributions in the soil than the scale of the economy itself.     

Spatial patterns and temporal changes of heavy metal distributions in river sediments in a region with multiple pollution sources

Purpose

The main purpose of this study was to evaluate temporal and regional variability of contamination by heavy metals (HMs) in river sediments using their enrichment factors (EFs) and benchmarking according to sediment quality guidelines (SQGs). The Zlin region in the Czech Republic (Morava and Drevnice River basins) represents a model area where several regionally specific ecological risk assessment studies have recently been conducted with a focus on organic pollution, eco-toxicity, geological, and geochemical characteristics.

Materials and methods

Four consecutive sediment sampling campaigns were undertaken in spring and autumn 2005–2006. Aqua-regia leachable content of Cd, Co, Cr, Cu, Ni, Pb, Sb, V, and Zn in surface sediments from 14 sites was analyzed using ICP-MS, and Hg content was analyzed using AMA-254 analyzer. EFs were calculated to identify the human impact on pollution in the area. Comparisons to SGQs were conducted to identify the areas and HMs of greatest risk.

Results and discussion

Calculation of EFs contributed to the effective clustering of HMs. Median EFs of Co, Ni, and V ranged from 0.9 to 1.4 at all sites indicating concentrations very close to natural geological background levels. There was greater enrichment at locally polluted sites, the highest in the cases of Cd, Sb, Hg, and Cr. Widespread influence of diffuse HM sources (traffic, agriculture, and urban wastes) was apparent from elevated concentrations of Pb, Cu, and Zn at all sites. EF values also helped to identify the greatest temporal changes and shifts in HMs contamination between adjacent sites caused by 50-year recurrence interval floods in early spring 2006. The impact was most apparent in downstream sites; namely directly below the confluence of the two major rivers.

Conclusions

The overall contamination of HMs in the region was classified as low-to-moderate with significantly contaminated sub-areas. The study showed relatively stable spatial distributions of HMs, indicating potential sources of pollution. Cu was identified as the HM of greatest risk. The study emphasizes the necessity of considering both environmental circumstances and background HM occurrence to prevent misinterpretation of the pollution situation. The use of EFs which include grain size proxy normalization and HM background levels, along with the comparison of the detected concentrations to SQGs, proved an efficient way to identify hazardous contamination from anthropogenic sources.     

运城市村级农业土壤重金属的空间分布与原因分析

通过检测运城市南薛村农业土壤8种重金属(Cu、Zn、Cr、Cd、Pb、Ni、As、Hg)含量,分析研究区内重金属空间分布特征和原因。与国家土壤环境标准的二级标准相比,Hg和Ni的超标率分别为16.50%和12.62%,Cd、Pb、As均未超标。按单项污染指数进行评价,主要污染物是Hg,污染指数为1.58,处于轻度污染级别,其余重金属的单项污染指数均小于1,处在安全域内。按内梅罗综合污染指数评价,61.65%的农业土壤重金属污染程度处于安全水平,18.45%的土壤处在警戒线上,15.53%的土壤为中度污染和严重污染,只有个别土壤属轻污染。Zn、Cr、Ni和As的块金效应介于25%~75%之间,同时受农药、化肥和母质因素的影响;Cu、Cd、Pb和Hg的块金效应大于75%,分别受粪肥、污水、汽车尾气和居民生活的影响。8种重金属含量空间分布差异显著,主要原因是不同地块间的生产方式不同,该研究对于试验区农业资源的合理配置、农业生产的科学管理和农产品的安全生产具有重要的指导意义。