矿业活动区农田土壤重金属累积风险的评判方法--以小秦岭金矿区为例

金属矿产资源开发活动通常会导致矿区土壤重金属含量的累积,选用科学的评价标准及方法成为评判、区分矿业活动农田土壤重金属累积影响和风险的关键问题。在简述土壤背景值和土壤环境质量标准含义的基础上,提出采用与矿区其他环境条件基本相同或相近的邻区耕作层土壤重金属元素的平均含量作为评判矿业活动重金属对耕作层土壤的累积影响的对照值。以2011年小秦岭金矿区80件耕作层土壤重金属含量为例,金矿开发活动区耕作层土壤重金属的累积风险研究表明,土壤重金属低风险以上样品数占总样品数百分比的排序为Hg＞Cd＞Pb＞Cu,矿业活动对土壤重金属累积的贡献率排序为Hg＞Cu＞Pb＞Cd＞Zn。土壤中的Cr、As、Zn元素有轻度累积但无风险。土壤中Hg元素的累积风险面积达到了187.77km＾2,占到研究区总面积的47.08%。其中,中、高风险的面积为99.55km＾2,土壤重金属累积风险极其严重。研究结果科学地评判了矿业活动对耕作层土壤重金属的累积影响及其贡献,为土壤污染防治指明了方向。     

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。     

Screening of extraction methods for Cd and As bioavailability prediction in rhizospheric soil using multivariate analyses

Heavy metals in tailings and mining wastes from abandoned mines can be released into adjacent agricultural field and bioaccumulated in crops or vegetables. Therefore, prediction of metal bioavailability has become an important issue to prevent adverse effect of bioaccumulated metals on human health. In this study, single and sequential extraction methods were compared using multivariate analysis to predict the bioavailability of Cd and As in contaminated rhizosphere soils. Single extraction using 0.1 M HCl for Cd and 1.0 M HCl for As had an extraction efficiency of 8–12% for soil Cd and 14–17% for soil As compared to total concentration extracted with aqua regia. Using sequential extraction, Fe–Mn-bound Cd (FR3) and residual Cd (FR5) were the dominant fractions representing 43 and 41% of total Cd concentration. For As, the strongly absorbed form (FR2) was the most abundant chemical fraction showing 45–54% of the total As concentration in soil. Multivariate analyses showed that single extraction with HCl and total concentration of Cd and As in soil were significantly correlated to potato and green onion plant tissue metal concentration. Although little information was obtained with multiple regression analysis because of multicollinearity of variables, the result of principle component analysis (PCA) revealed that the highest positive loading was obtained using total concentration of Cd and As in soil in the first principle component (PC1). In addition, total concentration of Cd and As in soil was independently grouped with other chemical fractions by cluster analysis. Therefore, the overall result of this research indicated that total concentrations of Cd and As in rhizosphere soils were the best predictors of bioavailability of heavy metals in these contaminated soils.     

小秦岭金矿区小麦和玉米重金属的健康风险评价

重金属污染引发的农产品质量安全问题已成为全社会关注的焦点。为了解小秦岭金矿开发引起的重金属污染风险,采集了同点位的农田土壤、小麦和玉米籽粒样品,测定了其中Hg、Pb、Cd、Cr、As、Cu和Zn的含量及其在土壤中的形态;采用指数法和RAC风险评价法分析了土壤重金属的污染风险,采用转移因子和目标风险指数法评价了小麦、玉米籽粒中重金属的健康风险。结果表明:小秦岭金矿区土壤中Hg、Pb、Cd、Cu、Zn含量受矿业活动影响强度大,在土壤中累积明显;土壤中Hg、Cd、Pb、Cu总量超过了国家限值,呈现污染;Cd、Hg、Cu具有潜在生态风险。小麦和玉米籽粒中Pb以及玉米籽粒中的Cd的平均含量高于国家标准,呈现一定程度的污染;部分小麦样品中的Hg、Cd和部分玉米样品中的Cd超过WHO/FAO安全限值,小麦和玉米籽粒中度Pb平均含量超过欧盟安全标准,说明具有潜在的健康风险。重金属的转移因子表明Cd、Zn及Cu比其他重金属更容易从土壤转移到小麦和玉米籽粒中;通过小麦对重金属的摄入量略高于玉米,远低于WHO/FAO推荐剂量;目标风险指数评价表明,只消费小麦或玉米基本不产生健康风险,但同时消费矿区生长的小麦和玉米具有较高的Pb健康风险。     

矿业活动区农田土壤重金属累积风险的评判方法——以小秦岭金矿区为例

金属矿产资源开发活动通常会导致矿区土壤重金属含量的累积,选用科学的评价标准及方法成为评判、区分矿业活动农田土壤重金属累积影响和风险的关键问题。在简述土壤背景值和土壤环境质量标准含义的基础上,提出采用与矿区其他环境条件基本相同或相近的邻区耕作层土壤重金属元素的平均含量作为评判矿业活动重金属对耕作层土壤的累积影响的对照值。以2011年小秦岭金矿区80件耕作层土壤重金属含量为例,金矿开发活动区耕作层土壤重金属的累积风险研究表明,土壤重金属低风险以上样品数占总样品数百分比的排序为HgCdPbCu,矿业活动对土壤重金属累积的贡献率排序为HgCuPbCdZn。土壤中的Cr、As、Zn元素有轻度累积但无风险。土壤中Hg元素的累积风险面积达到了187.77km2,占到研究区总面积的47.08%。其中,中、高风险的面积为99.55km2,土壤重金属累积风险极其严重。研究结果科学地评判了矿业活动对耕作层土壤重金属的累积影响及其贡献,为土壤污染防治指明了方向。     

小秦岭金矿区土壤重金属生物有效性与影响因素

土壤中重金属生物有效性与影响因素分析是土壤重金属风险管控的关键问题。通过实地调查、现场采样、实验测试、综合分析等方法,分析了研究区100km2内Hg、Pb、Cd、Cr、As、Cu、Zn七种重金属元素的有效态含量特征,研究了这些重金属有效态含量之间、有效态含量与全量、有效态与土壤pH、有机质含量、粒度等基本理化参数之间的相关性,分析了重金属污染来源。结果表明,土壤中Hg、Pb、Cd、Cr、As、Cu、Zn七种重金属有效态的平均含量分别为2.29mg/kg、594mg/kg、2.52mg/kg、6.30mg/kg、2.16mg/kg、48.14mg/kg、50.21mg/kg,其变异系数大小为:HgPbCuZnCdAsCr。Hg的变异系数最大,是由于金矿选矿活动采用混汞法提金排放的尾矿堆(库)分布不均。Hg、Pb、Cd、Cu、Zn有效态量与全量之间均存在显著的相关性;土壤有机质与重金属有效态之间存在显著的相关性;土壤pH与有效态重金属之间存在显著的负相关性;土壤粒度对重金属有效态的累积影响不明显。     

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。     

重庆秀山西北部农田土壤重金属生态健康风险评价

为了解矿业活动较多的重庆秀山县西北部农田土壤重金属污染状况,采集了表层土壤样品386件,分析测定As、Cd、Cr、Cu、Hg、Ni、Pb、Zn、Mn等9种重金属元素,采用地累积指数法、潜在生态危害指数法和健康风险评估模型,对该区土壤重金属污染程度、生态风险和健康风险进行评估。结果表明,该区农田土壤9种重金属平均值都高于重庆市土壤背景值,呈现不同程度的积累;Cd、Hg明显超出国家农用地土壤污染风险筛选值,超标率分别为75.2%和44.6%。土壤中Hg污染较严重,处于中污染或重污染状态,Mn、As、Cd总体呈轻污染,其余重金属基本无污染。生态风险评价显示,Hg、Cd为主要生态危害元素,Hg以强、很强和极强风险为主,Cd以中等风险为主。人体健康风险评价显示,儿童更易受到重金属污染威胁,重金属对成人不具有非致癌风险,对儿童具有非致癌风险,As、Cr是主要非致癌因子;成人致癌风险在可接受范围内,个别土壤样对儿童具有致癌风险,As致癌风险最大。     

武水河上游区域土壤重金属污染风险及来源分析

生态功能区在涵养水源、保持水土、维系生物多样性等方面具有重要的作用。本文以位于南岭生态功能区的流域——武水流域为研究对象,采集流域上游交通运输用地、采矿用地、工业用地、耕地及林地5种土地利用类型土壤样品,分析7种重金属Cd、As、Cu、Hg、Ni、Pb、Zn的含量特征,采用内梅罗综合污染指数评价重金属污染的程度,Hakanson潜在生态风险指数法评价土壤重金属潜在生态风险,并应用主成分分析法探究重金属污染的来源。研究结果显示,武水河上游地区土壤重金属Cd、As、Cu、Hg、Ni、Pb、Zn平均含量分别为1.28、72.44、54.62、0.27、68.32、72.29和158.42mg/kg,均高于土壤背景值,其中采矿用地土壤重金含量除Hg外均高于其他类型土壤。均值状态下土壤中Cd和As单因子污染指数分别为5.07、3.25,其中采矿用地中Cd单因子污染指数可达13.59;土壤重金属综合污染指数表明,采矿用地污染最为严重,其次是工业用地,林地呈安全状态。潜在生态危害指数评价结果显示,采矿用地和工业用地达到了强生态危害,其他类型土壤为轻微生态危害,而采矿用地土壤中Cd达到极强生态危害,As为强生态危害。土壤重金属来源研究结果表明,As、Cd、Cu和Zn来源于矿山开采及工业活动,Ni和Hg主要来源于成土母质,Pb则来源于交通运输。研究认为:武水流域上游区土壤重金属污染情况较为严重,Cd和As是区内主要的风险因子,主要来源于矿山开采以及工业活动。     

Distribution of Cd,Pb, Zn and Cu and their chemical speciations in soils from a peri-smelter area in northeast China

An exploratory study on soil contamination of heavy metals was carried out surrounding Huludao zinc smelter in Liaoning province, China. The distribution of total heavy metals and their chemical speciations were investigated. The correlations between heavy metal speciations and soil pH values in corresponding sites were also analyzed. In general, Cd, Zn, Pb, Cu and As presented a significant contamination in the area near the smelter, comparied with Environmental Quality Standards for Soils in China. The geoaccumulation index showed the degree of contamination: Cd > Zn > Pb > Cu > As. There was no obvious pollution of Cr and Ni in the studied area. The speciation analysis showed that the dominant fraction of Cd and Zn was the acid soluble fraction, and the second was the residual fraction. Pb was mostly associated with the residual fraction, which constituted more than 50% of total concentration in all samples. Cu in residual fraction accounted for a high percentage (40–80%) of total concentration, and the proportion of Cu in the oxidizable fraction is higher than that of other metals. The distribution pattern of Pb and Zn was obviously affected by soil pH. It seemed that Pb and Zn content in acid solution fraction increased with increasing soil pH values, while Cd content in acid soluble fraction accounted for more proportion in neutral and alkaline groups than acidic one. The fraction distribution patterns of Cu in three pH groups were very similar and independent of soil pH values. And the residual fraction of Cu took a predominant part (50%) of the total content.     

Heavy metals pollution and the identification of their sources in soil over Xiaoqinling gold-mining region,Shaanxi, China

In order to determine the characteristics of heavy metals’ pollution and identify their sources in the soil over the Xiaoqinling gold-mining region, Shaanxi, China, 133 soil samples were collected over the region, one sample was from a close point as background, and concentrations of Hg, Pb, Cu, and As in all samples were analyzed. Results indicated that the soil was polluted by these heavy metals, as their concentrations in the soil over the studied region were higher than that in the background zone. In addition, the result indicated that these metals had their specific spatial characteristics. Among the samples, those with higher concentrations of Hg, Pb, and Cu were mainly collected from the Shuangqiao river alluvial terrace area, the loess ravine tableland, and the piedmont alluvial–pluvial inclined tableland, which are the areas of gold-mining activities. Meanwhile, the samples with higher concentrations of As were distributed over the loess ravine tableland around Tongguan County, where agricultural activities were conducted intensively. Furthermore, the sources for all the heavy metals Hg, Pb, Cu, and As in the soil over each landscape were determined through analyzing the concentration correlation of these metals and comparing the maps of metal concentration distribution and land-use types. In Yellow river–Weihe river alluvial plain area, these heavy metals were mainly from agricultural activities. In the other landscapes, As was also mainly from agricultural activities; the other metals were contrarily from the gold-related activities. Interestingly, the correlation coefficients of As concentrations with Hg, Pb or Cu concentrations were positive in the samples from Yellow river–Weihe river alluvial plain area, and on the contrary, they were negative in the samples from the other landscapes. This result showed that the correlation can be used as an index to indicate properly the effect of the gold-related or agricultural activities on the heavy metals in the soil and identify their main sources over each landscape. As human activities resulted in the site-specific characteristics in the concentrations and sources of the heavy metals in each landscape, site-specific control strategies should be selected intensively to remedy landscape soil pollution. In Yellow river–Weihe river plain area, effective control strategies should be aimed at remedying As pollution caused by agricultural activities; in the other landscapes, Hg, Pb and Cu pollution caused by gold-mining activities should be considered.     

Spatial pattern of heavy metal concentration in the soil of rapid urbanization area: a case of Ehu Town,Wuxi City,Eastern China

Urbanization has an important effect on the soil ecosystem. Anthropogenic activities during urban sprawl are the sources and methods of migration, transition, and concentration of heavy metals in the soil. In this paper, the Yangtze River delta, the fastest urbanization area in China, was selected to study the influence of urbanization on heavy metal concentration in the soil. The analysis was performed on 218 samples collected from a typical industrial town in the delta. The content of six heavy metals (Hg, Cd, As, Pb, Cu, and Zn) was measured, which showed that the soil was seriously polluted by heavy metals, particularly Hg. In the study area, human activities were the major factors for the heavy metal concentration in the soil. The average content of Hg in the 0–500 m zone from the urban core was 1.4 mg/kg, about five times higher than the grade II threshold of the Chinese Environmental Quality Standard for Soils. The content of Hg, Cd, Pb, and Cu decreased gradually with increasing distance from the core of the built-up area, especially Hg. The influence of the anthropogenic activities was found to be anisotropic, and effects in the direction of 315° and 225° were most significant. Hg pollution in the 225° direction of the study area was more serious. These results suggested that the urbanization process affects not only the content but also the spatial pattern of heavy metal concentration in the soil.     

山东省沂南县东部土壤重金属地球化学特征及源解析

为查明山东省沂南县东部地区土壤重金属污染现状和污染源,系统采集了4 779件表层土壤样品,测试分析Cd、Hg、Pb、As、Cr、Ni、Cu、Zn元素含量及pH值,用地统计学、多元统计、空间分析等方法,探讨土壤重金属元素地球化学特征及其可能来源。结果表明,研究区土壤Hg含量均值略高于临沂市表层土壤背景值,另外7种元素含量均值与临沂市土壤背景值相当。与GB 15618—2018土壤环境质量农用地土壤污染风险管控标准筛选值相比,研究区土壤8种重金属元素浓度超标率低,但极大值的超标倍数较大,反映局部点式和小片污染较重。研究区8种元素含量水平总体表现出由西到东三级台阶下降的特征。研究区土壤中Cd、Pb、Zn、As高含量主要受控于自然源母岩,叠加了程度不同的工矿交通和农业活动因素;Cr、Ni几乎完全受控于成土母岩;Hg、Cu主要受控于沂南金场、铜井金矿采冶活动,其次受工业和交通排放以及农业粪肥、农药施用影响。     

云南个旧锡矿区矿业活动对土壤重金属的累积贡献

矿业活动是土壤重金属累积的重要原因之一。分析云南个旧锡矿区矿业活动区、与矿业活动区地质条件相同的矿业活动影响区和未受矿业活动影响的参照区表层土壤7种重金属元素之间的相关性,以参照区表层土壤重金属总量、参照区土壤重金属似背景值分别评价矿业活动对矿业活动区和矿业活动影响区土壤重金属的累积贡献量和贡献率。结果表明,矿业活动区重金属累积贡献率排序为PbZnAsCuCdCrHg,影响区重金属累积贡献率排序为PbZnAsCuCdCrHg,Pb、Cd、As、Zn、Cu与矿业活动关系密切,矿业活动区Pb、Cd、As均表现为极高累积和极高风险,应作为矿业活动治理的重点元素。     

河北平原农田土壤重金属元素Pb、Hg地球化学行为的影响因素

土壤重金属元素地球化学行为是目前国内外研究的热点。研究显示重金属元素地球化学行为与土壤理化性质有密切关系。本文选择河北平原农田为研究区,采集了325个根系土样品,测定了Pb、Hg有效态含量,并探讨了影响其地球化学行为的主要因素。研究表明:(1)Pb、Hg水溶态和离子交换态与土壤p H值呈显著负相关关系,土壤酸化使Pb、Hg有效性增加,直接导致农作物中Pb、Hg含量增加,保持土壤p H值在弱酸性至弱碱性范围,防止土壤酸化,可以降低重金属危害。(2)土壤中有机质含量与Pb、Hg全量呈显著的正相关性,但与水溶态和离子交换态呈负相关。所以土壤中有机质的增加可以降低Pb、Hg元素水溶态和离子交换态含量。(3)随着土壤黏粒的增加,Pb、Hg水溶态和离子交换态含量降低,说明黏粒可以吸附一定量的重金属离子,与重金属元素Pb、Hg地球化学行为存在一定关系。土壤p H值、有机质、黏粒是控制重金属元素Pb、Hg地球化学行为的重要因素。     

雄安新区西南部土壤重金属污染特征及生态风险评价

土壤重金属污染具有巨大的生态环境风险和危害。本文以雄安新区西南部(老河头镇、同口镇和芦庄乡)的表层土壤和大宗农作物小麦、玉米为研究对象,在对8种重金属As、Ni、Cu、Cr、Pb、Hg、Cd和Zn含量测试分析的基础上,开展了土壤重金属污染和生态风险评价。结果表明:研究区表层土壤局部存在重金属超标情况,重金属的污染程度依次为:Cd>As>Cu>Zn>Pb>Hg,Cr和Ni土壤环境清洁;研究区表层土壤重金属污染是人为源输入,老河头镇及周边大量有色金属冶炼活动是可能的主要污染源;8种重金属的潜在生态危害程度由强至弱依次为:Cd>Hg>As>Cu>Pb>Zn>Cr>Ni;多金属潜在生态风险指数RI的平均值为252,土壤整体的重金属潜在危害程度为中等风险,其中Cd对潜在生态风险指数RI的贡献最大,且Cd的活性最强,迁移能力强,易被植物吸收。研究成果可为雄安新区的土地利用规划提供重要依据。     

Modelling of modern mercury vapor transport in an ancient hydrothermal system: environmental and geochemical implications

Mercury has been used in some mineralizing hydrothermal systems as a significant pathfinder of Au and other elements. In addition, its geochemical behaviour reflects some characteristics related to the transport mechanism of metal-bearing fluids. In this work the authors analyse the geochemical aspects and the environmental impact of Hg mobilization from the old mining area of Valle del Azogue (VA), from smelting slags, mining waste and the partially exploited mineralization that remains a few metres underground. The main pathway of Hg is the transport of vapor from different foci, therefore a mathematical simulation of the process of Hg vapor transport was carried out in the Valle del Azogue (VA) mineral deposit. This is one of the two sites in Spain (the other being the famous district of Almaden), where Hg vapor emissions have been cited. The results obtained by means of mathematical simulation were compared with both the real Hg concentration values detected in the field (upper part of the mining area), and with the geochemical distribution patterns of Au and other elements related to the mineralization. A close relationship between the simulated Hg vapor distribution and soil gas concentrations was identified. It is proposed that the transport of Hg emissions from this old mining area could be the cause of present contamination of marine sediments in the area.     

攀西大梁子铅锌矿区水系沉积物重金属地球化学特征及源解析

长江上游是整个长江经济带的重要生态屏障。以长江上游攀西大梁子铅锌矿区水系沉积物为研究对象,查明了重金属元素含量的空间分布特征,分析了重金属来源,探讨了在不同pH条件下重金属的淋滤规律,并进行了生态风险评估。研究结果显示:攀西大桥河流域水系沉积物中重金属的空间分布极不均匀,其含量明显要高于长江水系沉积物中重金属的平均含量;重金属生态风险属于很强风险,Hg和Cd呈高度富集、严重污染;Pb和Zn呈中度富集、中等污染。淋滤实验结果表明Pb、Zn、Cd在酸性和中性条件下淋滤浓度先快速下降,后逐渐趋于平衡,而As在快速下降后又有缓慢升高的趋势。大桥河流域水系沉积物中As、Cd、Pb、Zn主要来源于大梁子铅锌矿的采选活动,Hg为岩石风化和土壤剥蚀来源,而Cu和Cr主要为农业和工业活动来源。综合对比发现,攀西成矿带铅锌矿周边土壤富Cd而贫Cr,此外Cd、Pb、Zn、Hg是主要潜在污染物,且生态风险程度较高。     

粉煤灰污泥添加剂对地下水质影响的模拟研究

通过测定土柱和淋洗液中重金属的含量,研究石灰岩质土壤应用粉煤灰污泥添加剂改良后重金属在土壤剖面上的分布移动特征及对地下水质的影响.结果表明:仅试验层内除As和Ni外,Zn、Cd、Pb、Cu、Cr、Hg含量明显增加,未出现明显向下移动的趋势;同时重金属淋出量明显增加,但未超过地下水Ⅲ级标准.初步认为与添加剂自身、重金属的特性及石灰岩质土壤滤层的截固作用相关.粉煤灰污泥经过合理的配施和预处理应用于石灰岩质矿区退化土壤的改良,短期内不会对地下水的质量产生明显的影响.     

不同耕作类型下土壤-农作物系统中汞、砷含量与生态健康风险评价

针对废弃矿山遗留生态环境问题,选择贵州丹寨废弃金汞矿为研究区,基于野外系统样品采集,通过原子荧光法和电感耦合等离子体质谱法分析了区内土壤和农作物中的汞(Hg)、砷(As)浓度,采用单指标污染标准指数法、单因子污染指数法、潜在生态危害指数法和目标危险系数法评价了区内Hg、As污染程度及生态健康风险.结果显示:旱地土壤Hg...