桂林灵川县典型有机水稻田重金属元素分布特征及污染评价

为了解桂林市灵川县有机水稻种植区土壤和水稻中重金属含量、分布特征及健康风险,选择典型田块采集了水稻根、茎、叶、稻穗及对应根系土样品10套,分别测定了土壤和植物样品中As、Cd、Cr、Cu、Hg、Ni、Pb、Zn共8种重金属元素含量以及土壤pH值,计算了各元素富集系数及转运系数,总结了水稻不同部位重金属元素富集迁移规律,并根据相关标准评价了土壤重金属污染及食品健康风险。结果表明:(1)研究区产出的稻米无食用安全风险,土壤重金属含量均低于风险管制值,但10份样品中有3份的Cd含量高于风险筛选值,且全部调查田块的环境质量均不符合绿色食品产地质量要求;(2)对比水稻不同部位的元素富集系数,发现大部分元素富集系数在根部最大,籽实最小。根、茎、叶、糙米的富集系数平均值分别为1.13、0.26、0.20、0.10;(3)对比不同元素的富集系数与转运系数发现,As易于从土壤聚集到根部,Pb的活动性较弱而不易被水稻吸收,Cu、Zn相对较易在水稻中转运。综上所述,并考虑到灵川县过去长期施用石灰带来的不利影响,建议当地相关部门对Cd超标风险引起注意,在控制石灰用量的同时加强土地质量监控,必要时采取增施有机肥料、种植低累积品种的水稻等措施,以降低水稻Cd超标的风险。     

河流沿岸土壤对上游矿山及矿山开发的环境地球化学响应——以广西刁江流域为例

刁江流域上游的矿山和矿山开发引发了显著的土壤环境地球化学变化,突出表现是沿岸形成了严重的土壤重金属污染带。污染带的分布与近20多年来的洪水淹没区和引水灌溉区呈现高度的一致性。上游地带的土壤污染区有明显的尾砂沉积,污染呈显性状态,而下游地带的尾砂沉积现象不明显,污染表现为隐性。无论是上游还是下游,土壤中的As、Pb、Zn、Cd含量均异常高。水田的犁底层对污染物质具有明显的隔断作用,而旱地淀积层中的污染物含量比较高,对污染物质的隔断作用不明显。污染耕地上生产的玉米中的Cd、Pb、Zn含量和大米中的Cd、Pb含量超过国家食品卫生标准。     

南方典型丘陵区酸性土壤重金属地球化学分布特征及来源分异解析

本文采用基于多元统计的APCS-MLR和基于GIS技术的地统计学相结合的方法,以广西南宁市郊区典型丘陵水稻种植区酸性土壤为例,有效的对土壤重金属的空间分布特征和来源分异进行了解析和验证。结果表明:(1)研究区8种重金属中除部分样点的Cd以外,其它元素含量均未超过国家土壤环境质量的二级标准。研究区土壤大部分未受到污染,少部分受到了轻污染,其中Cd处于轻污染的样品数最多;(2)重金属在不同岩性岩石中的含量差异较大;(3)研究区水稻产区农田土壤重金属来源主要包括土壤母质继承和农田施肥,其中值得注意的是农田施肥中引入较多的重金属为Hg和Cd。此外,研究区主要的岩石类型碳酸盐岩中含有较高含量的Cd和Hg;(4)本文研究结果对于南方丘陵区酸性土壤重金属污染的特征与防治的研究具有重要的参考意义。同时,本文所提出的绝对主成分得分(APCS)与GIS相结合的方法能够有效的对主成分分析的结果进行有效的补充和有力的验证,对于相关研究具有一定的示范意义。     

Soil contamination by metals with high ecological risk in urban and rural areas

Industrial development, intensive agriculture and fast urbanization have caused the metal contents of soils to increase to many times the allowable limits. To assess this impact on urban and rural soils, we quantified the Cd, Cr, Cu, Pb, Ni and Zn contents of 258 soil samples from the Recife metropolitan region (RMR). The objectives of the study were to estimate the probability of ecological risk, to determine the spatial pattern of the metals’ accumulation in the soil and to identify potential sources for the metals using a multivariate geostatistical approach. Mean concentrations of Zn, Cr, Pb, Cu, Ni and Cd in soils were 65.2, 17.9, 16.5, 12.8, 6.3 and 1.5 mg kg^?1, respectively. The results demonstrated that the Cd was anthropogenic in origin, the Cr and Ni were lithogenic (natural) in origin and the Cu, Pb and Zn were mixed in origin. Cd contaminated 91% of the samples; the median content of Cd (1.4 mg kg^?1) was three times the quality reference value for soil. The Cd contents of sugarcane fields exceeded the allowable limit (3.0 mg kg^?1) for agricultural areas. The spatial variability of the metals in the RMR showed that metallurgy, cement production, vehicle exhaust and vehicular traffic were the main sources of metals in urban areas, while phosphate-based fertilizers were the main sources in rural areas. More than 80% of the metropolitan region surveyed in the study was at moderate to high ecological risk.     

Arsenic in groundwater affected by phosphate fertilizers at São Paulo, Brazil

. This paper studies metalloid mobility in soils produced by conventional farming methods. The mobility of arsenic in soils depends on several factors including redox potential, soil mineralogy, pH, and the presence of other anions that compete with As for soil retention sites, for example, phosphate. Phosphate enhances the mobility of As in soils by competing for adsorption sites. Arsenic may accumulate in soil through the application of fertilizers. Ingestion of inorganic arsenic contained in drinking water is known to cause cancer. Studies were carried out in an area of Jundiaí, São Paulo in Brazil with high arsenic levels in natural water from domestic wells. The mobility of arsenic in the soil of Jundiaí was studied in the period 1998–2001. The application of phosphate fertilizers on a wide scale is a common agricultural practice. Based on data from the field and laboratory experiments, the deterioration of soil and groundwater quality is a result mainly of fertilizer use due to excessive P application, overdosing of soil with phosphate, and undesirable additions of arsenic in P fertilizers.     

氨基泡塑的合成及其应用于富集地质样品中的痕量金

采用泡塑(PUF)富集,AAS或ICP-OES测定地质样品中痕量金是常用的分析方法。与活性炭相比,PUF的选择性好,但吸附容量偏低,可将泡塑负载不同的萃取剂或修饰不同的官能团提高吸附容量。本文将聚醚型泡塑经盐酸水解制备成氨基泡塑(PUF-NH_2)。红外光谱和扫描电镜表征显示,PUF-NH_2峰形发生了明显红移(3376.5 cm-1),其中的氨基数量显著增加,另外PUF-NH_2的高分子出现明显断裂,发生水解后裸露出的氨基具有还原性,在吸附金的过程中易与金离子在PUF-NH_2表面发生氧化还原反应,形成金纳米颗粒。改性后的PUF-NH_2吸附容量达到96 mg/g,与PUF相比提高了8倍。将PUF-NH_2应用于富集地质样品中的金,经炭化灼烧、50%王水提取后用ICP-OES测定,金的加标回收率在95.0%~105.0%之间,检出限为0.15μg/g。实验证明用PUF-NH_2处理样品提高了富集倍数和分析灵敏度,有利于低品位矿石的分析。     

云蒙湖表层沉积物重金属分布特征及风险评价

为了解云蒙湖表层沉积物中重金属的污染状况,选取云蒙湖沉积物中6种重金属(Cu、Zn、Pb、Cr、Cd、As)作为研究对象,测定并分析其在云蒙湖表层沉积物中的分布、来源及生态风险,以期为云蒙湖沉积物中重金属污染治理及饮用水安全保障提供依据。采用富集系数法、相关性分析及聚类分析对重金属来源进行分析,并选用富集系数法、地累积指数法和潜在生态危害指数法对重金属污染程度及潜在生态危害进行了评价。结果表明:云蒙湖表层沉积物中6种重金属Cu、Zn、Pb、Cr、Cd、As平均含量分别为20.9、73.1、23.1、62.0、0.4和4.5 mg/kg;与临沂市土壤背景比较,Cd、Zn和Cr的含量超过临沂市土壤背景值,Cd污染最严重。重金属来源分析结果显示:Cd受人类活动影响较大,可能与区域农业和林业施肥有关;Cu、Zn、Pb、Cr和 As这几种重金属以自然来源为主。综合富集系数法、地累积指数法和潜在生态危害指数法3种评价方法的结果得出,云蒙湖表层沉积物中Cd 为最主要的污染元素,且具有较强的生态危害。     

长沙、株洲、湘潭三市土壤中重金属元素的来源

为追踪长沙、株洲、湘潭3个城市表层土壤中Cd、As、Pb等重金属元素的来源,分析了土壤、基岩、大气干湿沉降、水、悬浮物等介质之间重金属元素的质量平衡和土壤自身重金属元素含量随时间变化的特点。结果显示,除As外,区内基岩中的重金属元素含量低于克拉克值;残积物中Cd相对基岩贫化,As、Pb、Cu、Hg等重金属元素相对基岩的富集小于3倍;大气干湿沉降重金属元素相对土壤富集了数倍至数十倍;湘江水体主要向沿江潮土提供As、Cd物源:近50年内土壤重金属元素有较高的增加速率。不同介质间重金属元素的质量变化特点支持长沙、株洲、湘潭三市土壤重金属元素富集的主要物源为大气沉降,地表水及悬浮物是沿江湖土重金属元素的主要物源,基岩对土壤提供的物源有限的结论。     

用微生物对单一碳源利用方法探讨重金属在城市土壤中积累的环境效应

Biolog研究表明，英国阿伯丁市城市土壤的微生物群落结构显著有别于农村土壤，并使微生物对碳源的消耗量增加，消耗速度加快。城市土壤中不仅重金属Cu,Pb,Zn,Ni的含量明显高于农村土壤，而且其化学形态的主成分分析表明，有效态Pb,Zn,Cu及有机态Ni和Cu是导致城市土壤区分于农村土壤的主要因子。相关性分析表明，Biolog的这种变化规律与重金属的上述化学形态密切相关；典型变量分析表明，重金属对城市土壤微生物群落结果的这种损伤具有长期性效应及不可恢复性。     

某矿区土壤重金属分布特征及来源解析

为探究赣南某矿区土壤重金属污染状况及来源,以该矿区内40个土壤样品为研究对象,分析了土壤中Cu、Pb、Zn、Cr、Ni、Cd、As和Hg等8种重金属元素的含量,并采用频率直方图、相关性分析、主成分分析等多种统计方法探究了土壤重金属含量的分布特征及来源。研究结果表明:(1)研究区8种重金属中有7种不同程度地超过了江西省土壤重金属元素背景值;(2)Pb、Zn、As和Hg的含量接近正态分布,而Cu、Cr、Ni和Cd的含量则呈现出右偏分布的趋势,这可能与研究区矿山开采活动及土地利用类型等因素有关;(3)矿区土壤重金属相关性分析表明,Cu、Cr、Ni的同源性较高,可能具有相同的污染源,而Pb、Zn、Cd等元素与Cu、Cr、Ni相比,其来源可能存在一定的差异;(4)主成分分析结果显示,矿区内土壤中8种重金属元素含量可以由2个主成分来解释,所代表的实际意义按贡献率排序分别是成土母质和人为采矿活动;(5)矿区内土壤重金属污染物主要为Pb、Zn、Cd,人为采矿活动是这三种重金属污染的主要来源。     

北京市怀柔区土壤重金属的分布特征、来源分析及风险评价

在北京市怀柔区东南部农业区采集了977个表土样品,对其中Cr、V、Ni、As、Pb、Zn、Hg和Cd 8种重金属元素含量进行测试分析。通过地球化学成图清晰地呈现了这些元素的空间分布特征。利用数据统计分析,阐明了表土中这些重金属元素的含量分布特征,探讨了不同重金属的来源,并评估预测了其生态风险。研究结果表明Cr、V、Ni、As主要来源于成土母质;而Pb、Zn、Hg受交通和大气沉降等人类活动的影响较大;Cd则主要受到周边工厂以及农业施肥的影响。利用Hakanson法预测8种重金属的生态风险,除Cd外其他7种元素潜在生态风险均较低。本研究对怀柔区农业土壤的污染风险评价及土地利用规划具有一定的借鉴作用。     

太原盆地农田区大气降尘对土壤重金属元素 累积的影响及其来源探讨

通过研究太原盆地大气干湿沉降中重金属元素的含量分布特征及年输入通量,讨论其对土壤中重金属元素累积的影响。同时采用富集因子法探讨降尘物质的来源。研究结果表明,降尘中重金属元素As、Cd主要来源于人为活动,Pb的来源可能是人为源和自然源。而Hg则主要来源于自然源。     

Clay-Microbe Interactions and Implication for Remediation of Inorganic Contaminants

Mineral–microbe interactions indirectly affect the geochemical fluxes and biogeochemical cycling of a large number of elements. Among them are toxic heavy metals (e.g. chromium), radionuclides (uranium and technetium), and nitrogen. Heavy metals and radionuclides enter the environment from various sources such as mining activity, nuclear weapons production, metallurgical and chemical industries. Other metals, such as lead, arsenic, antimony, and cadmium, are enriched in certain environments by either natural or anthropogenic processes. Because many of these metals and radionuclides are carcinogens, their release into the environment and their fate cause intense scientific and public concern and are the subject of substantial research. Nitrate enters the environment largely through agricultural activity. Human health risks from nitrate uptake from drinking water supplies run the gamut from increased cancer risk to birth defects.     

Regional distribution pattern of groundwater heavy metals resulting from agricultural activities

Contaminations of groundwater by heavy metals due to agricultural activities are growing recently. The objective of this study was to evaluate and map regional patterns of heavy metals (Cd, Zn and Cu) in groundwater on a plain with high agricultural activities. The study was conducted to investigate the concentration of heavy metals and distribution in groundwater in regions of Shush Danial and Andimeshk aquifers in the southern part of Iran. Presently, groundwater is the only appropriate and widely used source of drinking water for rural and urban communities in this region. The region covers an area of 1,100 km² between the Dez and Karkhe rivers, which lead to the Persian Gulf. For this study, the region was divided into four sub-regions A, B, C and D. Additionally, 168 groundwater samples were collected from 42 water wells during the earlier months of 2004. The flame atomic absorption spectrometry (AAS-Flame) was used to measure the concentration of heavy metals in water samples and the Surfer software was used for determination of the contour map of metal distribution. The results demonstrated that in all of the samples, Cd and Zn concentrations were below the EPA MCLG and EPA secondary standard, respectively. However, the Cu contents of 4.8 % of all samples were higher than EPA MCL. It is also indicated that the concentrations of metals were more pronounced at the southern part of the studied region than at the others. The analysis of fertilizers applied for agricultural activities at this region also indicated that a great majority of the above-mentioned heavy metals were discharged into the environment. Absence of confining layers, proximity to land surface, excess agricultural activities in the southern part and groundwater flow direction that is generally from the north to the southern parts in this area make the southern region of the Shush plain especially vulnerable to pollution by heavy metals than by other contaminants.     

赣南地区土壤硒元素地球化学特征及其影响因素研究：以青塘—梅窖地区为例

以赣南青塘—梅窖地区为典型区开展详细的调查研究工作,共采集了表层(0~20 cm)土壤样品889件,农作物样品72件。系统地分析了土壤及农作物中硒元素含量的空间分布特征及其与成土母质、土地利用类型和土壤理化性质的关系。结果表明：研究区土壤硒平均含量为044 mg·kg-1,其中面积比例为4859%的土壤硒含量处于足硒状态,面积比例为4286%的土壤硒含量处于富硒状态。在空间分布上,缺硒和潜在硒不足土壤仅呈零星分布。表层土壤硒含量在一定程度上继承了成土母质硒的含量,不同的土地利用类型土壤中硒含量也存在一定的差异。土壤有机质含量与硒含量呈显著正相关关系,与土壤pH值没有相关性。花生和水稻富硒率较高,其中花生和早稻含量均符合国家食品安全标准,仅晚稻存在一定的重金属超标现象。通过对比富硒土壤和不富硒土壤中晚稻重金属含量的超标率、硒的富集系数和含量,发现在富硒区晚稻中重金属的超标率远远低于非富硒区,说明土壤硒元素会在一定程度上降低晚稻中重金属元素的富集效应。     

沈阳市新城子区土壤重金属元素的空间变异性

利用地质统计学方法,系统地研究了沈阳市新城子区土壤重金属元素的空间分布及空间变异性特征。研究结果显示,土壤中Cd和Pb的含量明显高于全国平均值和辽宁省土壤背景值。变异函数分析结果表明,Hg具有明显的空间自相关性,Cd、Pb和As均具有中等空间自相关的特征。Cd和Pb含量较高,并呈显著的正相关,主要受灌溉、施肥等外在因素的影响。重金属元素空间变异性的研究对当地土壤环境评价和土地质量评估具有一定的指示和引导作用。     

华东某铀矿区稻米中Cd含量及空间分布特征研究

利用等离子体质谱仪测定了某铀矿区周边稻米与对照区稻米中重金属元素Cd的含量,重点对铀矿区稻米中的Cd元素含量及其空间分布特征进行了研究。结果表明:(1)铀矿区内10.53%的稻米样品Cd含量超过国家标准,89.47%稻米样品中Cd的含量未超过国家标准(GB 2762-2005),而对照区稻米样品中Cd含量均远低于国家标准(GB 2762-2005);(2)铀矿区稻米中Cd含量远高于对照区稻米中Cd含量,尾矿堆积区、水冶厂和矿床开采区下游及周边区域内稻米中Cd元素含量明显高于上游地区或远离上述区域的其他地区。(3)矿床开采产生的废水与废渣、水冶厂的废液渗漏、尾矿露天堆积以及矿石运输过程中的矿渣洒落等原因可能是导致Cd元素随地表径流发生迁移进入稻田,从而使矿区稻米中Cd的含量较高的重要因素。     

江苏主要公路两侧农田土壤重金属污染现状初步研究

分析研究了宁通公路、204国道两条主要公路两侧农田土壤Pb、Cr、Ni、Zn、Cd含量分布特征、影响范围及其差异,并对公路旁农田土壤重金属累积程度、潜在生态危害进行了评价。结果发现,同一公路不同路段土壤重金属累积含量程度不同;两条公路两侧土壤重金属含量累积程度不高,潜在综合生态危害程度都很低,以轻微危害为主;而由汽车轮胎摩擦产生的Cd在公路两侧农田土壤中累积程度最高,为最主要的污染重金属;不同等级的公路两侧土壤重金属累积范围存在差异,宁通公路为0m-50m,204国道为0m-30m。     

Bottom ash of trees from Cameroon as fertilizer

Utilization of wood bottom ash as fertilizer additive contributes to the return of valuable nutrients to agricultural soils, especially when no artificial mineral fertilizer is being used. In general, wood combustion ash is enriched in calcium and potash, and may also contain elevated amounts of zinc, but the concentrations of these elements depend on tree species, part of the tree, harvest season and local soil type. In this study, bottom ash samples from eight different agricultural wood species from Cameroon, Africa were investigated by using X-ray diffraction and atomic absorption spectroscopy to determine the refractory components and the concentrations of selected heavy metals and arsenic. Results show calcite, potassium salts, periclase and quartz as major components. These phase contents were used to calculate major element concentrations, which were subsequently validated by X-ray-fluorescence analysis. The chemical compositions varied within the range of common compositions of wood ashes. Six of the ashes reached sufficient concentrations of calcium to be defined as a “calcium fertilizer”. Pb contents are most variable, ranging from 0.03 to 21.1 mg/kg. Concentrations of Ni, Cu, Zn, Cd, Pb, and As are all lower than the strictest limit concentrations required for wood ash fertilizers and therefore, the studied wood ashes can be used without environmental concern.     

Heavy metal concentrations in soils and plants in the vicinity of Arufu lead-zinc mine,Middle Benue Trough,Nigeria

This study focused on the influence of base metal mining on heavy metal levels in soils and plants in the vicinity of Arufu lead-zinc mine, Nigeria. Soil samples (0-15 cm depth) and plant samples were collected from cul-tivated farmlands in and around the mine, the unmineralized site and a nearby forest (the control site). The samples were analyzed for heavy metals (Fe, Zn, Mn, Cu, Pb, Cr and Cd) by Atomic Absorption Spectrophotometry (AAS). The physical properties of soils (pH and LOI) were also measured. Results showed that soils from cultivated farm-lands have neutral pH values (6.5-7.5), and low organic matter contents (10%). Levels of Zn, Pb and Cd in culti-vated soils were higher than the concentrations obtained from the control site. These heavy metals are most probably sourced from mining and agricultural activities in the study area. Heavy metal concentrations measured in plant parts decreased in the order of rice leavescassava tuberspeelings. In the same plant species, metal levels decreased in the order of ZnFeMnCuPbCrCd. Most heavy metals were found in plant parts at average concentrations normally observed in plants grown in uncontaminated soil, however, elevated concentrations of Pb and Cd were found in a few cassava samples close to the mine dump. A stepwise linear regression analysis identified soil metal contents, pH and LOI as some of the factors influencing soil-plant metal uptake.