广东长潭水库表层沉积物重金属污染特征与潜在生态风险评价研究

采用原子吸收方法分析了广东蕉岭长潭水库表层沉积物重金属（Cu、Pb、Zn、Cr、Ni、Cd、As、Hg）含量水平,以广东省红壤重金属环境背景值和我国《土壤环境质量标准》Ⅰ级自然背景值为参比标准,采用地积累指数和H覽kanson潜在生态危害指数法对长潭水库表层沉积物重金属污染特征及其生态风险进行评价。结果表明,长潭水库表层沉积物重金属污染较轻,Cu、Pb、Zn、Cr、Ni、As和Hg平均含量分别为55.7、65.1、280.9、30.7、16.2、10.9mg·kg-1和0.05mg·kg^-1,Cd在所有沉积物中未检出。重金属地积累指数和潜在生态风险指数评价结果显示,长潭水库处于无污染至中度污染范畴,具有轻微潜在生态风险。工农业生产、生活污水排放及旅游观光等人为活动及自然因素是长潭水库重金属污染的重要来源。对库区上游的农业面源污染应引起相关部门重视。     

北京城市流域底泥重金属形态特征及其生态风险评价

为了解北京城市流域底泥重金属污染现状及其生态风险,研究分别在北京市永定河流域、潮白河流域、温榆河流域、拒马河流域和泃河流域五大河系（北京段）共设置84个检测样点,采集底泥样品,利用ICP-MS分析法和BCR连续提取法测定北京城市流域底泥中铜（Cu）、锌（Zn）、铬（Cr）、镉（Cd）、镍（Ni）和砷（As）6种主要重金属的含量,分析其分布特征及养分变化,同时运用潜在生态危害指数法和地累积指数法综合评价流域底泥中重金属的生态风险。结果表明:（1）以北京土壤质量标准为北京市参比值,北京流域中下游底泥富营养化严重,重金属富集强弱依次为Cd > （Cr,As,Zn） > （Cu,Ni）;（2）底泥重金属潜在生态危害评价,其危害程度依次为Cd > （Cr,As,Zn） > （Cu,Ni）,其中五大河流下游潜在生态风险较大,生态风险最大的是拒马河水域;（3）地累积指数法进行污染评价,北京河流污染程度依次为下游 > 中游 > 下游,底泥中污染最大的重金属为Cd,其次为Cr,As和Zn,污染较小的为Cu和Ni。综上所述,北京污染较大的河流依次是拒马河、永定河、潮白河、温榆河和泃河,特别是河流下游区域底泥重金属累积较多,潜在生态危害最大。     

贵州草海沉积物重金属污染特征及潜在生态风险分析

为研究重金属在草海沉积物中富集污染状况,以7种毒性重金属为研究对象,从不同方位对草海沉积物中重金属进行采样测试,分析重金属含量水平及空间分布特征,同时应用潜在生态危害指数法进行评价。结果表明,草海沉积物中重金属富集特征为Zn〉Cr〉Pb〉Cu〉As〉Cd〉Hg,且在空间分布上呈现从湖心向边缘逐渐减少的趋势,重金属污染程度表现为Cd〉Hg〉Zn〉Pb〉As〉Cu〉Cr,在Cd的潜在生态风险系数高贡献下,沉积物中重金属潜在生态风险指数均大于150,多数达到严重程度。     

丹河水系表层沉积物重金属污染及生态风险评价

采用原子吸收分光光度法和原子荧光光谱法,测定了丹河水系干流及主要支流表层沉积物中重金属（Mn、Zn、Cu、Pb、Cd、Cr、Hg、As）的含量,同时用沉积物质量基准法（SQG）和Hakanson潜在生态风险指数法,对重金属的毒性效应、污染程度及潜在生态风险进行了评价,并分析了重金属的主要来源。结果表明,丹河水系表层沉积物中Mn、Zn、Cu、Pb、Cd、Cr、Hg、As的平均含量分别为115.1、18.78、8.46、6.49、2.85、60.6、0.047、14.22mg·kg-1。Cd、As和Cr的含量介于最低效应水平（LE-L）与严重效应水平（SE-L）之间。根据SQG,丹河表层沉积物中重金属含量处于中度污染水平,可能会对河流生物产生一定的毒性效应,而Pb、Cu、Zn则尚无毒性效应。除了As和Cr之外,其他重金属元素之间均呈现较明显的正相关,表明在沉积物中这些重金属的含量具有共同的变化趋势,且具有一定的同源性。工业排污是造成丹河水质恶化的主要原因之一,也是重金属的主要来源。以山西省土壤背景值为参比进行Hakanson潜在生态风险指数评价发现,丹河水系表层沉积物呈现由强至极强的生态风险,其中Cd生态风险最大,Hg、As次之。对单个重金属的潜在生态风险系数和多个重金属的潜在生态风险指数进行分析显示,生态风险较大的样点是高平市、巴公河和水东。研究结果旨在得到单一污染物的环境影响和多种污染物的综合效应的评价结果,为丹河水系沉积物及水体重金属污染防治和决策管理提供科学依据。     

天水市蔬菜大棚土壤重金属污染特征及生态风险评价

[目的] 对甘肃省天水市蔬菜大棚土壤重金属污染程度和生态风险进行评价,为该地区设施农产品安全生产提供科学依据。[方法] 以天水市大棚蔬菜主产区21个乡镇的362个土壤样品为研究对象,用电感耦合等离子体质谱仪（ICP-MS）测定As,Ni,Cu,Zn,Cd,Pb,Hg含量,采用内梅罗综合污染指数和潜在生态风险指数对蔬菜大棚土壤重金属环境质量和潜在生态风险进行评价;利用相关分析和主成分分析对土壤重金属的可能来源进行探讨。[结果] ①7种元素平均含量均未超出《土壤环境质量农用地土壤污染风险管控标准（试行）》（GB15618-2018）的土壤风险筛选值;但与甘肃省土壤背景值相比,Cu,Zn,Cd,Pb和Hg积累普遍,分别是背景值的1.9,1.4,3.1,1.3,5.2倍;②内梅罗综合污染指数平均值为0.508,9.9%的点位出现了轻度和中度污染;多金属潜在生态风险指数的平均值为289,Hg对潜在生态风险指数的贡献率为61.3%;③7种元素被识别出3个主成分。[结论] 蔬菜大棚土壤重金属90%以上点位处于安全水平,潜在生态风险为轻微—中度等级,Hg是最大的潜在风险因子。重金属轻度、中度污染和潜在生态风险强、极强的点位较为集中的分布在耕作年限高、人口密集的城镇和交通沿线。     

上海市某大型再开发场地土壤重金属污染特征、评价及来源分析

[目的]研究土壤中重金属污染与生态风险状况,为保障城市更新改造过程中土地的合理利用提供科学依据。[方法]以上海市某大型再开发利用场地为研究对象,采集了102个点位的表层(0-0.5 m)和下层(1.5-2.0 m)土壤样品,测定10种重金属(As,Be,Cu,Pb,Ni,TI,Zn,Cd,Cr和Hg)浓度,采用地累积指数、内梅罗指数和潜在生态风险指数进行土壤重金属污染和生态风险评价,并进一步利用多元统计分析方法揭示土壤中重金属的来源情况。[结果]①测试土壤中重金属均未超过《土壤环境质量建设用地土壤污染风险管控标准(试行)》(GB36600-2018)第二类用地风险筛选值,但6.9%,24.5%,25.5%,37.3%和63.7%的采样点土壤中As,Cu,Pb,Zn和Hg浓度超过土壤元素背景值,存在不同程度的累积现象。内梅罗指数评价结果表明研究区域土壤整体处于尚清洁到轻度污染状态,分别有11.8%和3.84%的表层区域与2.64%和0.63%的下层区域土壤呈中度污染和重度污染状态。②表层土壤综合潜在生态风险指数均值为89.91,处于中等风险水平,Hg为研究区域主要的生态风险因子。③土壤中Ni,Cr,Be和TI浓度主要受成土母质风化作用的自然源控制,Pb,Zn,Cu,As和Hg主要受交通运输源和历史农业活动源的影响,其中自然源对表层土壤中的As和下层土壤中Cu也有相当比例的贡献,而表层土壤中Hg更多受到除交通运输源以外的其他人类活动源影响。[结论]后续土地利用过程应注重Hg的生态风险管控,并提高对外来交通源引起的重金属累积效应的关注。     

大沽河湿地表层沉积物重金属分布特征及污染评价

胶州湾属半封闭海湾,水体交换能力较弱,受多条河流入海影响,污染日趋加重,通过大沽河的径流量、输沙量和溶解污染物占到胶州湾入海河流的首位。根据区域特征,于2009年2、5、8、11月对大沽河湿地48个采样点表层沉积物中的Cu、Zn、Pb、Cd、Hg、As、有机碳、粒度进行测定,探讨了重金属含量和污染特征与总有机碳、粒度的关系,利用污染评价法和潜在生态风险评价法进行污染和风险分析。结果表明：胶州湾大沽河湿地表层沉积物重金属含量较低,大部分测站符合海洋沉积物质量（GB 18668—2002）Ⅰ类标准的要求。表层沉积物中Cu、Pb、Zn含量8月份最高、2月份次之、5月份最低。Pb、Hg、As 3种重金属含量在2月份最高。Cu、Pb、Zn和Cd重金属之间存在显著正相关关系,Hg与As存在明显的相关关系;除Cd和As外的4种重金属与沉积物粘土、有机碳含量之间也存在显著正相关性。重金属单因子污染程度总体较轻,属于低污染水平,污染程度依次为Hg〉Cd〉Pb〉Cu〉As〉Zn。大沽河河口区表层沉积物重金属潜在生态风险总体处于较低水平,风险程度依次为Hg〉Cd〉Pb〉Cu〉As〉Zn。     

小埠东橡胶坝对沂河临沂城区蓄水段沉积物重金属分布的影响

为探讨小埠东橡胶坝对沂河临沂城区蓄水段沉积物重金属分布和富集的影响,利用柱状沉积物采样器在橡胶坝前2km处(对照)和坝前50m处分别获取原位柱状沉积物,在比较分析典型重金属Cu、Pb、Cd、Cr、Hg和As分布特征的基础上,对重金属污染程度及潜在生态风险进行评价。结果表明,橡胶坝前50m处采样点表层沉积物(0-4cm)Cu、Pb、Cd、Cr、Hg和As的平均含量均显著高于对照点,垂向分布上,橡胶坝前50m采样点同对照点相比,重金属含量均具有随深度增加而逐步减小的趋势,说明橡胶坝的建成改变沉积物重金属的分布与富集状况,促进坝前沉积物中重金属的富集,建坝后水动力条件的改变是其富集的主要原因。地积累指数评价法和潜在风险评价法一致表明,临沂城区蓄水段表层沉积物As、Cr和Pb污染较轻,污染程度为无或无-中,具有轻微的生态危害;Cu和Cd的污染程度分别为中和中-强,具有轻微和很强的生态危害;Hg处于极强污染,具有极强的生态危害。潜在风险评价法表明,橡胶坝前50m采样点和对照点重金属的风险水平分别为HgCdCuPbAsCr和HgCdCuAsPbCr,Hg为最主要生态风险贡献因子。     

北京市农业土壤重金属污染环境风险等级评价

为全面了解北京市农业土壤中重金属污染环境风险等级及空间分布特征,采用Hakanson潜在生态危害指数法对1018个采样点的Cr、Ni、Cu、Zn、As、Cd、Pb、Hg 8种重金属进行污染的潜在生态风险评价,并运用指示克里格方法绘制污染风险概率分布图,对整个北京市农业土壤重金属污染风险的空间分布特征进行分析。结果表明：北京市农业土壤重金属污染风险已达到中度和低度,低度、中度、重度和严重4个风险等级的样点比例分别为42.63%、34.97%、18.57%、3.83%,8种金属中Cd和Hg元素污染风险最高,Cr、Ni、Zn元素生态风险较低,风险概率图显示城区周围、大兴、通州、密云等地风险等级较高。     

三峡库区典型农业区土壤重金属污染特征及风险评价

为了解三峡库区农业区土壤重金属污染现状及环境风险水平,该文以重庆市8个典型农业区县(铜梁、云阳、万州、丰都、城口、垫江、南川和江津)土壤为研究对象,共采集表层(0~20 cm)土壤样品160个,依照《土壤环境监测技术规范(HJ/T 166-2004)》和《土壤环境质量标准GB 15618-1995》分析了土壤样品中8种重金属(As、Cd、Cr、Cu、Hg、Ni、Pb和Zn)的含量,比较了不同区县8种重金属污染现状及差异,应用地积累指数法和潜在生态风险指数法探讨了研究区土壤重金属的累积特征及潜在生态风险等级。结果表明:该研究区农业土壤8种重金属含量平均值均未超过《土壤环境质量标准GB 15618-1995》二级标准,与土壤背景值相比,Cd、Cr、Cu、Hg和Zn均具有极显著差异(P0.01),As、Ni和Pb差异不显著,8个区县Cr均表现出极显著差异(P0.01),城口区多种重金属均表现出极显著差异(P0.01),8种重金属地累积指数平均值均小于0,研究区土壤受重金属污染水平为未污染等级,单个重金属潜在生态风险顺序为HgCdAsHgCuNiCrZn,Hg元素潜在生态风险指数平均值为43.840,属中等生态风险等级,其余元素生态风险指数值均小于40,属于低生态风险等级,8种重金属综合潜在生态风险指数平均值为108135,为低生态风险等级。综合研究结果表明:三峡库区典型农业区土壤Cd、Cr、Cu、Hg和Zn具有一定程度的累积,且表现为多种重金属复合累积现象,Cr累积具有普遍性,Hg是影响三峡库区农业土壤综合潜在生态风险的主要元素,但研究区土壤重金属总体处于低生态风险水平。     

汉江上游汉中段河流表层沉积物重金属污染风险评价

通过监测汉江上游汉中段河流表层沉积物重金属Pb,Cu,Zn,Cd,Cr的浓度,分析了各元素的含量分布特征,并选用Hakanson生态风险指数法对研究区进行了环境风险评价。结果表明,汉江上游汉中段各监测点重金属富集顺序为:Cd >Zn >Pb >Cr >Cu。单个重金属的污染指数C_fⁱ显示,汉江上游汉中段监测点仅有Cu的含量均值为0.83,小于1,为轻微污染;Pb,Zn,Cd,Cr的均值分别为1.06,1.25,1.33,1.02,略大于等于1,处于轻微污染以上水平,达到中度污染水平。综合分析多项重金属污染系数C_d,单项重金属的潜在生态风险系数E_rⁱ和多种重金属的生态系统的潜在生态风险指数I_R可知,汉江上游汉中段各监测点沉积物重金属污染属于轻微生态危害。     

Distribution,risk assessment,and source analysis of heavy metals in sediment of rivers located in the hilly area of southern China

Purpose

River sediment, the important sink and source of heavy metals, can provide critical information for aquatic ecosystem health. Heavy metal pollution has been a serious problem facing river systems worldwide and can adversely affect human beings via the food chain. However, no comprehensive study has been conducted on heavy metal pollution in sediments of river systems in the hilly area of southern China, which plays a key role in water supply and ecosystem balance. This study is aimed at comprehensively studying the pollution status of heavy metals in river sediments in the hilly area of southern China and apportioning sources.

Materials and methods

A total of 39 superficial sediment samples were collected from the upstream, midstream, and downstream of 13 rivers (Xiangjiang River, Zishui River, Yuanjiang River, and Lishui River located in Hunan Province; Ganjiang River, Xinjiang River, Fuhe River, Raohe River), and Xiushui River located in Jiangxi Province; Qiantangjiang River and Oujiang River located in Zhejiang Province; Minjiang River and Jiulongjiang River located in Fujian Province) in the hilly area of southern China. The total concentrations of metals of Mn, Zn, Cr, Co, Ni, Cu, As, Cd, Sb, Pb, and V were analyzed using the inductively coupled plasma-mass spectrometry method. The pollution status and potential ecological risk were assessed with the geoaccumulation index (I_geo), sediment quality guidelines (SQGs), and potential ecological risk index (RI). The source apportionment of heavy metals was performed by correlation analysis and principle component analysis (PCA).

Results and discussion

Results indicated that Mn, Zn, and Pb concentrations were significantly higher than other metals, especially in the upstream of the Jiulong River and midstream and downstream of the Xiangjiang River. Pollution assessment indicated that Cd pollution of sediments was most serious and that more than 50% of sampling sites were significantly polluted, with a very high potential ecological risk. The rivers in Hunan provinces (HN) were identified as the priority controlled rivers because of the high I_geo and RI index values. Correlation and PCA analysis indicated that Mn, Pb, and Zn originated from natural and mineral exploitation activities; As, V, Ni, and Sb originated from industrial wastewater and mineral-smelting activities; Cu and Co originated from agricultural activities; Cr and Ni originated from natural sources. While the most polluted Cd came from a combination of multiple sources described above.

Conclusions

Results indicated that Cd was the most common heavy metal pollutant, especially in river sediments of Hunan Province. Anthropogenic activities have become the main source of heavy metals in the river sediments of the hilly area of southern China. Special attention should be paid to Cd, and measures must be taken to prevent from further anthropogenic influence on heavy metal pollution.

     

闽江大樟溪下游沿线湿地沉积物中重金属

基于2018年7月采集的大樟溪下游沿线湿地表层沉积物样品,探讨了6种重金属(Pb、Cr、Cu、Zn、Ni、Cd)的沿程分布特征,并运用地累积指数法(Igeo)和潜在生态风险指数法(RI)对其生态风险进行了评估。结果表明,湿地沉积物中重金属的平均含量整体表现为Zn>Pb>Cr>Cu>Ni>Cd,且其沿程变化较为一致,而这主要取决于沉积物粒度组成、磁学参数、pH、EC和有机质的沿程分布。湿地沉积物中的6种重金属含量均于桃花洲、耕櫵亭、方庄村和奥莱时代出现较低值,原因主要与4个采样点的采砂活动改变了河流水沙条件使得沉积物发生粗化有关。湿地沉积物中6种重金属之间均存在极显著正相关关系(P<0.01),说明其具有同源性,并可能代表了一个因采砂/采石活动以及建筑/生活垃圾堆放导致的复合污染源。大樟溪下游沿线湿地大部分样点的Pb处于轻度污染状态,而Cd处于中度污染状态。6种重金属平均单项潜在生态风险指数(E■)表现为Cd>Pb>Ni>Cu>Cr>Zn,Cd具有强生态风险。所有样点重金属的平均RI值为228.62,说明湿地整体处于中等生态风险。研究发现,尽管大樟溪下游沿线湿地沉积物中的重金属含量相比闽江上游其它支流和闽江中下游河段处于一个较低水平,但其Pb、Cd污染及生态风险(特别是Cd)仍较为突出,故下一步在加强对沿线湿地管控时应给予特别重视。     

黄河下游典型滩区土壤重金属污染特征及来源解析

针对黄河滩区土壤重金属污染、来源复杂的问题，该研究以原阳滩区复合污染土壤为例，结合土壤重金属含量空间分布和正定矩阵因子分解（positive matrix factorization, PMF）模型，探讨滩区土壤重金属富集特征及来源。源解析结果表明，原阳滩区土壤重金属污染受工业源、交通源、自然来源、燃煤污染源和农业源影响，农业源占主导，相对贡献率达23.5%，其次为工业源、自然来源、交通源、和燃煤污染源。该研究能够准确解析多金属复合土壤复杂成因，可为黄河滩区多金属复合污染土壤的污染源识别提供参考。     

三峡库区重金属含量空间分布及污染状况

[目的] 对三峡库区坡面土壤与消落带沉积泥沙中重金属含量特征开展研究,为该区重金属污染评价提供理论与数据支持。[方法] 在三峡库区选取53个采样点,分析区域内坡面土壤与消落带沉积泥沙中Cr,Cu,Pb,Zn,Mn 5种重金属元素的含量,利用单因子污染指数法、内梅罗综合指数法、地累积指数法和潜在生态风险指数法开展污染状况评价。[结果] 研究区域内重金属含量平均值大小依次为：Mn>Zn>Cr>Cu>Pb,仅Cu,Zn和Mn存在污染。Zn和Mn在消落带沉积泥沙与坡面土壤中皆富集,而Cu仅在坡面土壤中富集。研究区域内重金属在空间分布上呈上、下游高,中游低分布。单因子污染指数法表明,研究区内仅存在Zn （P_ia=1.07）的轻度污染与Mn （P_ia=2.65）的中度污染。研究区域内梅罗综合指数为2.93,为中度污染。根据地累积指数法,研究区域内仅存在Mn轻度污染,其余重金属皆为无污染。Cr,Cu,Pb,Zn,Mn的潜在生态危害皆为轻微生态危害;研究区域的综合生态危害指数为14.09,为轻微生态危害。[结论] 研究区域内Cr含量主要受到研究区地质背景影响,而Cu,Pb,Zn和Mn含量同时受到地质背景与人类活动的影响。研究区内存在Mn和Zn污染,且有轻微生态危害。     

Pollution assessment and spatial variation of soil heavy metals in Lixia River Region of Eastern China

Purpose

The effect of soil heavy metals on crops and human health is an important research topic in some fields (Agriculture, Ecology et al.). In this paper, the objective is to understand the pollution status and spatial variability of soil heavy metals in this study area. These results can help decision-makers apportion possible soil heavy metal sources and formulate pollution control policies, effective soil remediation, and management strategies.

Materials and methods

A total of 212 topsoil samples (0–20 cm) were collected and analyzed for eight heavy metals (Cd, Hg, As, Cu, Pb, Cr, Zn, and Ni) from agricultural areas of Yingbao County in Lixia River Region of Eastern China, by using four indices (pollution index (PI), Nemerow pollution index (PI_N), index of geo-accumulation (I _geo), E _i /risk index (RI)) and cluster analysis to assess pollution level and ecological risk level of soil heavy metals and combining with geostatistics to analyze the concentration change of heavy metals in soils. GS+ software was used to analyze the spatial variation of soil heavy metals, and the semi-variogram model is the main tool to calculate the spatial variability and provide the input parameters for the spatial interpolation of kriging. Arcgis software was used to draw the spatial distribution of soil heavy metals.

Results and discussion

The result indicated that the eight heavy metals in soils of this area had moderate variations, with CVs ranging from 23.51 to 64.37 %. Single pollution index and Nemerow pollution index showed that about 2.7 and 1.36 % of soil sampling sites were moderately polluted by Cd and Zn, respectively. The pollution level of soil heavy metals decreased in the order of Cd?>?Zn?>?Pb?>?As?>?Cu?>?Cr?>?Ni?>?Hg. The I _geo values of heavy metals in this area decreased in the order of Zn?>?Cd?>?As?>?Pb?>?Cu?>?Cr?>?Hg?>?Ni. According to the E _i index, except Cd that was in the moderate ecological risk status, other heavy metals in soils were in the light ecological risk status, and the level of potential ecological risk (RI) of soil sampling sites of the whole area was light.

Conclusions

The results of four indices and the analysis of spatial variation indicated that the contents of Cd and Zn were contributed mainly by anthropogenic activities and located in the south-east of this study area. However, the contents of Hg, As, Cu, Pb, Cr, and Ni in soils were primarily influenced by soil parent materials.

     

Sources and Ecological Risks of Heavy Metals in Soils Under Different Land Uses in Bangladesh

Soil heavy metal pollution, influenced by both natural and anthropogenic factors, significantly reduces environmental quality. In this study, Cr, Ni, Cu, As, Cd, and Pb in eight different land-use soils from Patuakhali District in Bangladesh were assessed. Concentrations of Cr, Ni, Cu, As, Cd, and Pb in soils were 1-87, 5-271, 4-181, 0-80, 0.2-24.0, and 5-276 mg kg^-1, respectively, measured using an inductively coupled plasma-mass spectrometer. The enrichment factor, pollution load index (PLI), and contamination factor (C_fⁱ) of metal i were used to assess the ecological risk posed by metals in soils. The PLI ranged from 0.78 to 2.66, indicating baseline levels to progressive deterioration of soil due to metal contamination. However, C_fⁱ of Cd ranged from 1.8 to 12.0, which showed that the studied soils were strongly impacted by Cd. Considering the severity of the potential ecological risk of a single metal, the descending order was Cd > As > Pb > Cu > Ni > Cr. Soils under all land uses showed moderate to very high potential ecological risk.     

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.     

黔西煤矿区周边土壤重金属形态特征、污染评价及富集植物筛选

[目的]研究黔西某煤矿区周边土壤重金属污染情况、重金属形态潜在风险及其周边重金属富集植物,为当地的重金属污染防治提供科学依据。[方法]采用潜在生态风险评价及模糊数学法的两种评价方法(单因素决定模型和加权平均模型)对煤矿区及非煤矿区土壤进行重金属生态风险评价,对影响土壤肥力的土壤理化指标进行检测,利用风险评估编码法对重金属形态进行分析,并采用生物富集系数法对煤矿区周边富集重金属植物进行筛选。[结果]煤矿区Hg,Cd,As,Zn,Cr及Ni平均值含量分别是背景值的2.47,3.65,2.00,1.23,1.74,1.69倍。煤矿区潜在生态危害趋势为:CdHgAsNiCrPbZn。模糊数学法单因素决定模型评价显示,非煤矿区污染大于煤矿区,加权平均模型则反之。煤矿区Cd,Cr,Cu,Mn,Ni,Pb及Zn潜在风险指数分别为69.17%,7.97%,8.24%,40.10%,45.29%,53.70%及29.90%。蜈蚣草对As富集系数大于1.00,火棘、构树、盐肤木、马桑、凤尾蕨及金丝梅等对Cd富集系数大于1.00,马桑及白蒿对Pb富集系数大于1.00。[结论]煤矿区存在重金属污染,以Cd,As,Hg较为严重。煤矿区周边土壤中重金属对环境构成的潜在风险顺序为:CdPbNiMnZnCuCr。对当地而言,蜈蚣草可作为煤矿区周边修复As污染的先行植物,凤尾蕨可作为修复Cd污染的先行植物,马桑可作为修复Pb污染的先行植物。     

西安市汽车站地表灰尘中重金属的污染评价及其来源识别

[目的]研究西安市长途汽车站地表灰尘中重金属的主要成分、可能来源及其污染水平,为改善汽车站内及周边环境现状提供科学依据。[方法]利用X-Ray荧光光谱仪对西安市内20个具有代表性的汽车站地表灰尘中Cu,Mn,Ni,Pb,V和Zn的元素含量进行分析,采用地积累指数法及潜在生态风险指数法评价灰尘重金属的污染水平及环境风险,利用主成分分析。聚类分析等方法来研究城市汽车站地表灰尘中重金属的主要成分及其可能来源。[结果]Cu,Pb,Zn均在不同程度上超过陕西省土壤背景值,其含量的平均值分别为36.3,107.7,113.5mg/kg。地积累指数法评价表明,除Pb为中度污染以外,其余元素均为无污染;潜在生态风险指数法表明,西安汽车站地表灰尘中的重金属元素处于中等污染水平,具有中等潜在生态风险。[结论]Cu,Mn和Ni主要来自于自然源和交通源,Pb和Zn主要来自汽车尾气的排放及零部件的磨损,V则主要来自于自然源。