黄河包头段常见离子对重金属在沉积物上吸附影响机制研究

常见阴阳离子对重金属在黄河包头段相对清洁河段表层沉积物中的吸附影响研究结果表明,不同的环境离子浓度范围内,起主导作用的影响机制不同,黄河包头段水环境中Na 、Mg2 和Ca2 对Zn2 的吸附影响较大,K 对Cu2 、Pb2 、Zn2 和Cd2 吸附影响均较大,Cl-、SO2-4对Cu2 、Pb2 、Zn2 和Cd2 的吸附影响均较小,而HCO-3;对Pb2 的影响较小,对Cu2 、Zn2 、Cd2 的吸附影响较大.     

抗性真菌对Pb2+、Zn2+和Cu2+的吸附特性研究

从铜陵市某矿区土壤中筛选出1株对重金属Pb2+、Zn2+和Cu2+具有抗性的真菌,命名为TL-3。以TL-3为实验菌株,在不同pH值、不同金属离子初始浓度、不同菌体量以及不同吸附时间条件下对Pb2+、Zn2+和Cu2+进行吸附实验,研究其吸附特性与对不同金属离子的吸附能力。结果表明,TL-3对Pb2+、Zn2+和Cu2+的最佳pH值为5.0。在最佳条件下,吸附量在Pb2+,Zn2+和Cu2+的初始浓度分别为200mg/L、300mg/L和200mg/L达到最大,分别为20.61mg/g,23.17mg/g和17.46mg/g。TL-3对三种重金属的吸附均在20h达到吸附平衡。     

广州市万亩果园土壤重金属污染调查与评价

运用实地调查采样及地积累指数法、单因子污染指数法、综合污染指数法等方法对广州市万亩果园土壤的重金属（Cd、Pb、Cu、Zn）污染情况进行了调查分析与评价．结果表明：万亩果园土壤中Cd、Cu污染不容忽视,其中Cd污染最为严重,Cu、Zn次之,Pb污染较少;在《广州市海珠区果树保护区总体规划》划分的不同等级保护区中,针对研究区域,一级保护区土壤重金属综合污染指数为0．732,属较清洁（警戒线）等级,二级保护区土壤重金属综合污染指数为1．792,属轻度污染等级,其中Cd为主要污染物,其次是Cu;三级保护区Cd污染严重,单因子污染指数高达6．390,土壤重金属综合污染指数为4．699,属于重污染等级．在垂直分布上,随土层深度增加,万亩果园土壤重金属含量呈现Cd递增,Cu、Zn递减,Pb先增后减的规律;一级保护区以农业污染源为主,二级保护区农业污染源与工业污染源并存,三级保护区以工业污染源为主．通过在轻污染区添加石灰、羟基磷灰石等化学修复剂,在重污染区积极调整种植结构,发展清洁生产,防止土壤重金属通过食物链危害人体健康．     

博斯腾湖流域绿洲农田土壤重金属污染及潜在生态风险评价

新疆博斯腾湖流域绿洲采集195个农田土壤样品,测定其中As、Cd、Cr、Cu、Mn、Ni、Pb和Zn等8种重金属元素的含量,基于地统计法分析农田土壤重金属空间分布规律,采用污染负荷指数（PLI）和潜在生态风险指数（RI）评价农田土壤重金属污染和潜在生态风险程度,并对重金属的来源进行讨论。结果表明：① 博斯腾湖流域农田土壤Cd、Cr、Cu、Ni、Pb和Zn含量平均值分别超出新疆土壤背景值的1.67倍、1.13倍、1.15倍、1.29倍、2.11倍和1.65倍。② 农田土壤中8种重金属元素空间分布基本呈现岛状分布格局,各金属元素在部分区域出现高值区,表明研究区人类活动对农田土壤环境具有负面效应。③ 农田土壤Pb呈现中度污染,Cd、Cr、Cu、Ni和Zn轻度污染,Mn轻微污染,As无污染。农田土壤重金属污染负荷指数的平均值为1.09,呈现轻度污染态势。④ 各重金属元素单项生态风险指数平均值从大到小依次为：Cd、Ni、As、Cu、Pb、Cr、Zn。综合生态风险指数平均值为18.63,处于轻微生态风险态势。从生态风险程度的区域差异来看,各县生态风险指数从大到小依次为：和硕县、博湖县、焉耆县、和静县。⑤ 农田土壤Cr、Cu、Mn、Ni与Zn主要受到土壤地球化学成因的控制,As、Cd和Pb主要受到人类活动的影响。Cd与Pb是研究区主要的污染因子,研究区农田土壤中Cd与Pb污染必须关注。     

山丘平原过渡区土壤重金属污染特征及评价——以四川省五通桥区为例

采集和分析了五通桥区不同功能区和乡镇73个土壤样品，以了解山丘平原过渡区土壤重金属的含量和污染特征。结果表明，重金属的平均含量为Pb32．18mg／kg、Cd0．82mg／kg、Cu28．61mg／kg、Zn108．08mg／kg、Ni32．66mg／kg、Cr72．44mg／kg；与四川土壤背景值相比，Cu、Ni、Cr的含量与之持平，Pb增加了0．11倍，Zn增加了0．32倍，Cd的积累较为严重，比背景值增加了10倍。污染评价结果显示该过渡区存在一定程度的重金属污染问题，不同功能区的污染程度排序为工业区〉生活区〉农业区。Cd在六种元素的土壤污染分担率中占55．46％，是最主要的污染元素；土壤Cd含量与Pb和Zn存在较高的相关性（相关系数为0．525和0．500），表明存在Pb—Cd和Zn—Cd的复合污染。     

海南省农产品产地土壤环境质量评价

采用单项质量指数与综合质量指数相结合的方法,对海南省农产品产地的土壤进行了重金属Cd、 Hg、 As、 Pb、 Cr、 Cu、 Zn和Ni含量的抽样调查分析与评价。结果表明,海南省农产品产地土壤重金属的平均含量均低于“HJ 332-2006”（食用农产品产地环境质量评价标准）规定的限值,土壤重金属的单项质量指数均≤0．7,综合质量指数为0．33,土壤环境质量均为1级,属于清洁水平,适宜发展无公害农产品。同时发现,部分产地的土壤中重金属含量有超标现象,海口有部分样品Cd、 Hg、 Cr、 Cu和Ni超标,三亚有部分样品Cd和Hg超标,儋州、澄迈均以Ni超标为主,琼海有部分样品Cr、 Cu和Ni超标。重金属含量之间多呈正相关关系,其中As与Pb、 As与Cu、 Cr与Zn、 Cu与Zn之间的相关性达到了极显著水平, Cd与Hg、 Pb、 Ni, Pb与Cu, Cr与Cu, Cu与Ni之间的相关性达到了显著水平。大部分监测点土壤中重金属含量均高于海南省水稻土自然背景值,表明在监测点土壤中产生了重金属累积。     

托素湖沉积物中重金属元素分析及地球化学特征研究

首次对托素湖沉积岩芯上部沉积物的重金属元素Cr、Cd、Cu、Zn和Pb的含量进行分析测试。精确测得沉积物中Cr,Cd,Cu,Zn和Pb的平均浓度分别为32.9 mg.kg-1,2.2 mg.kg-1,19.5 mg.kg-1,188.5 mg.kg-1和32.3 mg.kg-1。与区域背景值和标准值相比,托素湖沉积物样品中Cd和Zn都偏高。研究结果表明除了Cd污染程度比较严重,托素湖当前的Cr、Cu、Zn和Pb污染程度相对较轻。各元素经Ti校正后的分析结果显示,重金属元素含量在沉积剖面的10cm处出现波动性增大的明显转折,表明托素湖沉积物中Cd、Cr、Cu、Zn和Pb主要来源于流域侵蚀的造岩矿物元素,Cd污染可能源于人类活动所致。 关键词：托素湖;重金属元素;污染程度;地球化学特征     

托素湖沉积物中重金属元素及地球化学特征研究

对托素湖沉积岩芯上部沉积物的重金属元素Cr、Cd、Cu、Zn和Pb的含量进行分析测试。精确测得沉积物中Cr、Cd、Cu、Zn和Pb的平均浓度分别为32.9 mg·kg-1、2.2 mg·kg-1、19.5 mg·kg-1、188.5 mg·kg-1和32.3 mg·kg-1。与区域背景值和标准值相比,托素湖沉积物样品中Cd和Zn都偏高。研究表明,除了Cd污染程度比较严重,托素湖当前的Cr、Cu、Zn和Pb污染程度相对较轻。各元素经Ti校正后的分析结果显示,重金属元素含量在沉积剖面的10 cm处出现波动性增大的明显转折,表明托素湖沉积物中Cd、Cr、Cu、Zn和Pb主要来源于流域侵蚀的造岩矿物元素,Cd污染可能源于人为活动。     

乌鲁木齐市米东区农田土壤重金属含量的空间分布特征

利用地理信息系统（GIS）及地统计学方法,对乌鲁木齐米东区农田土壤中重金属（Hg、Cu、Zn、Pb、Ni、Cd及Cr）的含量进行空间变异性分析。结果表明：除Cu、Zn、Pb和Hg超过土壤背景值外,7种重金属的平均含量均未超过国家环境质量二级标准（GB15618-1995）;7种重金属均具有较好的空间变异结构,可以用指数模型、球状模型和高斯模型拟合,且具有不同程度的块金效应;Cd、Cr具有强烈的空间自相关性,Pb、Ni、Cu、Zn和Hg属中等强度空间相关, 说明其含量受外源污染的影响较大;采用普通克里格插值法得出7种重金属的空间分布图,除Cd空间分布规律不明显外,其它6种重金属均存在显著的空间分布规律。     

沙漠颗粒物对磷酸盐的吸附动力学研究

研究了乌兰布和沙漠和库布齐沙漠颗粒物在黄河水体中对磷酸盐(P)的吸附动力学及其影响因素和吸附/解吸平衡质量浓度(EPC0值)。结果表明：①不同沙漠颗粒物对P的吸附能力各不相同,但吸附速率均在前 8 h内较快,以后逐渐趋缓,在48 h时基本达到吸附平衡。磷初始浓度和颗粒物浓度均对颗粒物吸附P有一定影响;②颗粒物对P的吸附过程均符合准二级吸附动力学模型及Weber-Morris扩散方程,吸附过程主要由P在颗粒物内的扩散过程控制;③入河沙漠颗粒物在黄河水体中对P的吸附过程存在一个吸附/解吸平衡点,该点对应的不同颗粒物对P的EPC0值为0.010~0.042 mg·L-1,且其值均大于相应黄河水体中的P浓度,说明沙漠颗粒物入河后有向水体释磷的趋势。     

Heavy Metal Concentrations in the Intertidal Gastropod Nerita lineata and Their Relationships to Those in Its Habitats： A Case Study in Dumai Coastal Waters

Concentrations of heavy metals in the intertidal gastropod Nerita lineata collected from 4 sampling stations in the intertidal zone of Dumai coastal waters have been analyzed and correlated with the respective metal concentrations in their habitat. The objective of this study was to evaluate the possible relationships between heavy metal concentrations in the N.lineata with metal concentrations in their habitat, which include seawater, algal mat, suspended particulate matter, and surface sediment. The results showed that heavy metal concentrations in the sediment, N.lineata, suspended particulate matter, algal mat and surface seawater were found to be higher in stations closed to Dumai city center which has more industrial and anthropogenic activities. The mean concentrations of Cd, Cu, Pb, Zn, Ni and Fe in the N.lineata collected from Dumai intertidal area were 4.14 μg/g, 5.90 μg/g, 44.43 μg/g, 3.74 μg/g, 20.73 μg/g, 24.91 μg/g in shell; 4.16 μg/g, 7.31 μg/g, 51.78 μg/g, 17.63 μg/g, 23.52 μg/g, 30.60 μg/g in operculum and 0.71 μg/g, 15.09 μg/g, 9.41 μg/g, 94.42 μg/g, 5.10 μg/g, 398.24 μg/g dry weight in the total soft tissue, respectively. Cd, Pb and Ni concentrations of parts of the N.lineata were in the order: that of operculum>shell>soft tissue whilst Cu, Zn and Fe concentrations of parts of the N.lineata in the order: that of soft tissue>operculum>shell. This suggested that N.lineata could be used as biomonitoring agent for Cu, Zn and Fe (soft tissues) and for Cd, Pb and Ni (operculum). However, the shell had significant correlations (P<0.05) with metal concentrations in the sediment, algal mat, suspended particulate matter and seawater. Bioconcentration factor (BCF) values of the shell also revealed greater capacity for non-essential metals bioaccumulation from all environmental phases. This might suggest that the shell of N.lineata could be better used as biomonitoring agent for heavy metal pollution.     

Heavy metals and phosphorus in tidal flat sediments of the Yangtze estuary

Concentrations of heavy metals (Cu, Pb, Zn, Cr and Cd), and phosphorous (P) were determined in surface tidal flat sediments of the Yangtze estuary and Shanghai coast. Results demonstrate that there were significant differences among the accumulation of the heavy metals in sediments, following the order: Zn > Cu > Cr > Pb > Cd. The spatial distribution and chemical forms of heavy metals in tidal flat sediments were closely related to the distribution of pollution resources (outlet of sewage) and the local sedimentary and hydrodynamic conditions. The dominated form of non-residual heavy metals is bound to Fe/Mn oxides, and the next form is bound to carbonates. Moreover, contents of total P in sediments range from 18.0 μmol.g-1 to 31.4 μmol.g-1 along the coastline, speciation of P in sediments was different, most of P in tidal flat sediments is associated with calcium phases (as Ca-P) similar to marine sediments.     

Heavy metal pollution of soils and vegetables in the midstream and downstream of the Xiangjiang River, Hunan Province

A total of 219 agricultural soil and 48 vegetable samples were collected from the midstream and downstream of the Xiangjiang River (the Hengyang–Changsha section) in Hunan Province. The accumulation characteristics, spatial distribution and potential risk of heavy metals in the agricultural soils and vegetables were depicted. There are higher accu-mulations of heavy metals such as As, Cd, Cu, Ni, Pb and Zn in agricultural soils, and the contents of Cd (2.44 mg kg-1), Pb (65.00 mg kg-1) and Zn (144.13 mg kg-1) are 7.97, 3.69 and 1.63 times the corresponding background contents in soils of Hunan Province, respectively. 13.2% of As, 68.5% of Cd, 2.7% of Cu, 2.7% of Ni, 8.7% of Pb and 15.1% of Zn in soil sam-ples from the investigated sites exceeded the maximum allowable heavy metal contents in the China Environmental Quality Standard for Soils (GB15618-1995, Grade II). The pollution characteristics of multi-metals in soils are mainly due to Cd. The contents of As, Cd, Cu, Pb and Zn in vegetable soils are significantly higher than the contents in paddy soils. 95.8%, 68.8%, 10.4% and 95.8% of vegetable samples exceeded the Maximum Levels of Contami-nants in Foods (GB2762-2005) for As, Cd, Ni and Pb concentrations, respectively. There are significantly positive correlations between the concentrations of Cd, Pb and Zn in vegetables and the concentrations in the corresponding vegetable soils (p<0.01). It is very necessary to focus on the potential risk of heavy metals for food safety and human health in agricultural soils and vegetables in the midstream and downstream of the Xiangjiang River, Hunan Province of China.     

湘江中下游农田土壤和蔬菜的重金属污染

从湖南省湘江中下游衡阳-长沙段沿岸采集219 个农田土壤样品和48 个蔬菜样品, 测 试其中As、Cd、Cr、Cu、Ni、Pb、Zn 等7 种重金属元素的含量, 并结合GIS 作图与数据统 计, 对农田土壤中重金属空间分布、土壤和蔬菜中重金属富集特征以及其潜在风险进行分析。 结果表明, 农田土壤中As、Cd、Cu、Ni、Pb 和Zn 含量均大于湖南省相应土壤重金属含量背 景值, Cd (2.44 mg kg^-1)、Pb (65.00 mg kg^-1)、Zn (144.13 mg kg^-1) 含量分别超标7.97、3.69 和 1.63 倍。与我国《土壤环境质量标准》(GB15618-1995) 中II 级标准(pH 6.5~7.5) 比较, 土壤 As、Cd、Cu、Ni、Pb 和Zn 含量的超标率分别为13.2%、68.5%、2.7%、2.7%、8.7%和 15.1%, 表现为以Cd 为主的多种重金属混合污染。菜地土壤中As、Cd、Cu、Pb 和Zn 的含 量( 几何均值) 分别高于水稻土As、Cd、Cu、Pb 和Zn 含量。与《食品中污染物限量》 (GB2762-2005) 等标准比较, 蔬菜As、Cd、Ni、Pb 含量的样本超标率分别为95.8%、68.8%、 10.4%和95.8%; 蔬菜Cd、Pb、Zn 含量与相应土壤的Cd、Pb、Zn 含量存在极显著的相关性 (P < 0.01)。湘江中下游的农田土壤和蔬菜中重金属污染的潜在风险值得关注。     

湘江中下游农田土壤和蔬菜的重金属污染

A total of 219 agricultural soil and 48 vegetable samples were collected from the midstream and downstream of the Xiangjiang River（the Hengyang-Changsha section）in Hunan Province.The accumulation characteristics,spatial distribution and potential risk of heavy metals in the agricultural soils and vegetables were depicted.There are higher accumulations of heavy metals such as As,Cd,Cu,Ni,Pb and Zn in agricultural soils,and the contents of Cd（2.44 mg kg^-1 ）,Pb（65.00 mg kg^-1 ）and Zn（144.13 mg kg^-1 ）are 7.97,3.69 and 1.63 times the corresponding background contents in soils of Hunan Province,respectively. 13.2%of As,68.5%of Cd,2.7%of Cu,2.7%of Ni,8.7%of Pb and 15.1%of Zn in soil samples from the investigated sites exceeded the maximum allowable heavy metal contents in the China Environmental Quality Standard for Soils（GB15618-1995,Grade Ⅱ）.The pollution characteristics of multi-metals in soils are mainly due to Cd.The contents of As,Cd,Cu,Pb and Zn in vegetable soils are significantly higher than the contents in paddy soils.95.8%, 68.8%,10.4%and 95.8%of vegetable samples exceeded the Maximum Levels of Contaminants in Foods（GB2762-2005）for As,Cd,Ni and Pb concentrations,respectively.There are significantly positive correlations between the concentrations of Cd,Pb and Zn in vegetables and the concentrations in the corresponding vegetable soils（p〈0.01）.It is very necessary to focus on the potential risk of heavy metals for food safety and human health in agricultural soils and vegetables in the midstream and downstream of the Xiangjiang River,Hunan Province of China.     

北京市小麦籽粒的重金属含量及其健康风险分析

为评价北京市小麦重金属含量及其健康风险,采集北京市现有小麦种植区土壤和小麦籽粒对应样品68份,分析其重金属含量,并估算消费导致重金属摄入量。结果表明:北京市麦地土壤重金属As、Cd、Cr、Cu、Ni、Pb和Zn的平均值分别为7.46、0.165、37.8、20.3、24.2、14.3和70.1mg/kg,处于比较清洁水平。这说明小麦种植这种土地利用方式并不会导致土壤重金属升高。小麦籽粒中重金属含量,除Cr与食品卫生标准限值没有显著性差异外,其他元素均显著低于相应标准限值。普通人群通过小麦制品消费,As、Cd、Cr、Cu、Ni、Pb和Zn的摄入量分别为0.005、0.004、0.136、0.994、0.041、0.024、4.75mg/人 · d。北京小麦种植的主要4个区中,顺义产小麦的Cr、Cu、Ni和Pb导致的重金属摄入量高于其他3个区,房山产小麦导致的重金属摄入量最低。对于普通人群而言,通过小麦和蔬菜摄入重金属没有明显风险。     

湛江观海长廊红树林土壤-植物体系重金属富集与迁移规律

选取湛江市霞山区观海长廊红树林湿地为研究区域,运用电感耦合等离子体质谱仪（ICP-MS）测定红树林表层土壤及红树植物根、枝、叶中重金属（铜Cu、锌Zn、铅Pb、镉Cd、铬Cr、镍Ni、砷As）的质量分数;运用Hakanson潜在生态风险指数评估红树林土壤的重金属污染风险水平,结合相关性分析和聚类分析探讨重金属的影响因素及来源;应用生物富集系数（BCF）、转运系数（TF）分析重金属在土壤-植物中的富集和迁移能力。结果表明：1）研究区表层土壤7种重金属分布规律为Zn（57.48 mg/kg）>Cr（29.31 mg/kg）>Pb（19.23 mg/kg）>Cu（16.62 mg/kg）>Ni（8.18 mg/kg）>As（6.00 mg/kg）>Cd（0.20 mg/kg）。7种元素平均质量分数均未超过《土壤环境质量标准-农用地土壤风险管控标准》（GB15618-2018）（pH≤5.5）风险筛选值;Cu、Zn、Cd和As平均质量分数分别为广东省土壤背景值的2.08、2.74、6.75和1.11倍。2）重金属中Cd的潜在生态风险系数最高,潜在生态风险程度为很强,其余元素潜在生态风险程度为轻微。研究区土壤重金属的潜在生态风险程度为中等。重金属与有机质、黏土、粉砂呈正相关关系,与pH、砂呈负相关关系。3）Zn、Cr和Cu在红树植物体内质量分数较高,Pb、Ni和As次之,Cd质量分数最低。除无瓣海桑Zn的根-叶转运系数＞1外,重金属在桐花树、木榄和无瓣海桑中的生物富集系数和转运系数均＜1,说明桐花树、木榄和无瓣海桑对重金属的富集和转运能力不强,大部分有毒元素主要积累在根部,降低了有毒重金属通过食物链传递的风险。     

东莞市农田土壤和蔬菜重金属的含量特征分析

从东莞市采集118 个农田土壤样品和43 个蔬菜样品, 测试其中Cu、Zn、Ni、Cr、Pb、 Cd、As 和Hg 等8 种重金属元素的含量, 并结合GIS 制图和数据统计, 对农田土壤中重金属 的空间分布和来源、土壤和蔬菜中重金属的富集特征及其潜在风险进行了分析。结果表明, 农田土壤中Cu、Zn、Ni、Pb、Cd 和Hg 等元素含量均高于相应元素的广东省土壤背景值, 其中, Pb (65.38 mg kg^-1) 和Hg (0.24 mg kg^-1) 含量分别为其对应背景值的1.82 和2.82 倍。与我国《土壤环境质量标准》中II 级标准(pH < 6.5) 相比, 土壤中Cu、Ni、Cd 和Hg 含量样本超标率分别为3.4%、5.9%、1.7%和28%, 表现为以Hg 为主的多种重金属共同污染。土壤 中8 种重金属中Cu、Zn、Ni、Cr 和As 等元素主要来源于成土母质, Pb、Hg 和Cd 等元素主要与人类活动有关。空间分布上, Cu、Zn、Ni、Cr、Pb、As 和Hg 等7 种重金属含量呈现出西部高、东部低的特点, Cd 含量在西北部和东南部较高, 西南部较低。与《食品中污染物限量》(GB2762-2005) 等相关标准比较, 蔬菜中Ni、Pb 和As 含量的样本超标率分别为4.7%、16.3%和48.8%。蔬菜中重金属富集系数的顺序为: Cd > Zn > Cu > As > Ni > Hg > Cr > Pb。     

Heavy metal concentrations of agricultural soils and vegetables from Dongguan, Guangdong

A total of 118 of agricultural soil and 43 of vegetable samples were collected from Dongguan City, Guangdong, China. The spatial distribution, sources, accumulation characteristics and potential risk of heavy metals in the agricultural soils and vegetables were depicted in details by three different approaches, including total contents of eight metal elements in soils and vegetables, GIS maps and multivariate analysis of heavy metals in soils in the study. The results show that there are higher accumulation of heavy metals such as Cu, Zn, Ni, Pb, Cd and Hg in agricultural soils, and the contents of Pb (65.38 mg kg?1) and Hg (0.24 mg kg?1) are 1.82 and 2.82 times of the background contents of the corresponding heavy metals in soils of Guangdong Province, respectively. There are about 3.4% of Cu, 5.9% of Ni, 1.7% of Cd and 28% of Hg in all collected soil samples from all investigated sites which have overran the contents for heavy metals of the China Environmental Quality Standard for Soils (GB15618-1995, Grade Ⅱ). The pollution characteristics of multi-metals in soils are mainly reflected by Hg. There are different sources to eight metal elements in soils, Cu, Zn, Ni, Cr and As are predominantly derived from parent materials, and Pb, Hg and Cd are affected by anthropogenic activities. The spatial distribution shows that the Cu, Zn, Ni, Cr, Pb, As and Hg contents of agricultural soils are high in the west and low in the east, and Cd contents are high in the northwest, southeast and low in the southwest in Dongguan. The ratios of vegetable samples which Ni, Pb and As concentrations higher than the Maximum Levels of Contaminants in Foods (GB2762-2005) are 4.7%, 16.3% and 48.8%, respectively. The order of bio-concentration factors (BCF) of heavy metals in vegetables is Cd > Zn > Cu > As > Ni > Hg > Cr > Pb. It is necessary to focus on potential risk of heavy metals for food safety and human’s health from agricultural soils and vegetables in Dongguan City, Guangdong Province.     

中水灌溉下重金属在土壤中的垂直迁移及其对地下水的污染风险

中水灌溉是解决水资源短缺的潜在途径,关于中水灌溉条件下土壤中重金属的迁移行为及其对浅层地下水的污染风险至今仍缺乏研究。本文通过土柱模拟试验,分析中水灌溉条件下重金属在土壤中的迁移趋势及其对浅层地下水的污染风险。试验用添加重金属（As、Cd、Cu、Pb浓度分别为2、0.2、20、20 mg.kg-1）的人工污水和中水以1年、3年的灌溉量进行土柱淋溶实验。结果表明,淋溶20天（1年的灌溉量）以及60天（3年的灌溉量）,灌溉水中的As、Cd、Cu和Pb主要在表层（0¹0cm）累积。随着淋溶时间的延长,4种重金属（尤其是Cd）表现出向下迁移的趋势。但与地下水I级水质标准（GB/T14848-93）相比,淋滤液中4种重金属均未超标。因此,从本文的模拟试验来看,以北京市当前的中水进行灌溉,As、Cu、Pb对浅层地下水的污染风险不大。