基于区间数排序法的农田土壤重金属生态风险分析

将土壤中重金属浓度以区间形式表示,运用土壤重金属生态风险分析模型得出风险区间。为区分风险等级并引入区间数排序法,建立了一种基于不确定性的区间数排序法的土壤重金属污染风险评价模型。运用该模型对不同研究区域土壤重金属生态风险和同一研究区域土壤中不同重金属生态风险进行分析。结果表明,A采样区的风险最大,其区间排序向量为0.275 5,区间向量排序为ABDEC,与内梅罗综合污染指数排序结果一致。区间数排序法考虑到评价过程中的不确定性,避免主观因素的影响。因此,土壤重金属生态风险量化结果更加客观直观,为风险管理提供较为精确的理论依据。     

基于重金属有效态的农田土壤重金属污染评价研究

目前农田土壤重金属污染评价以重金属全量为依据,而评价农田土壤重金属污染影响时主要考虑农产品安全从而保障人体健康,农作物对重金属的吸收积累量则取决于土壤中有效态重金属含量。在阐述土壤重金属有效态定义的基础上,综合分析了土壤重金属有效态的影响因素及其与土壤中重金属全量和农作物中重金属含量的相关性,概括了土壤重金属有效态在土壤重金属污染评价中的应用,以期提出建立以土壤重金属有效态含量为基础、结合土壤重金属全量及作物中吸收的重金属含量的土壤重金属污染评价体系。     

我国高速公路周边土壤重金属污染现状及研究进展

以我国高速公路周边土壤重金属为研究对象，综述了我国高速公路周边土壤重金属污染特征、影响因素、来源、环境风险及其研究进展。高速公路周边土壤主要受Pb、Cd、Cr、Cu、Zn等重金属污染，主要呈现指数分布、偏态分布和两者混合分布等特点，并且受到土地利用、风向、地形、车流量等多种因素的综合影响。土壤重金属的来源除了受成土母质等自然因素影响以外，公路交通和周边工农业活动也会对其来源产生较大影响。传统的土壤重金属评价方法主要采用单因子指数法、地累积指数法、生态风险评价法等对重金属的污染等级和环境风险进行评价。未来的研究应将重金属形态分析、空间和地统计分析、重金属稳定同位素示踪和源解析模型以及预测模型等多种手段相结合，开展高速公路周边土壤重金属的污染特征、时空分布、来源及预测预警研究等，为我国高速公路沿线工农业生产布局及其土壤重金属污染防控提供科学依据和决策支撑。     

江苏沿海滩涂土壤重金属风险分析

以江苏沿海滩涂作为研究区，通过采样检测，结合统计分析方法和潜在生态风险指数，研究不同滩涂围垦类型下土壤/沉积物重金属总量、有效态含量及其潜在生态风险。研究结果表明：滩涂土壤重金属总体呈轻度污染，高值区位于养殖区和行道树林；不同土地利用类型下的重金属以中等偏下变异为主，空间异质性弱；重金属有效态与总量呈显著正相关；潜在生态风险主要由Cd、Hg贡献，64.78%和35.21%的土壤点位呈现Cd强度和中度生态风险，养殖池塘和农田重金属潜在生态风险最严重。     

湖南省某冶炼厂周边农田土壤重金属污染及生态风险评价

利用野外采样与实验室分析相结合的方法,以湖南省某冶炼厂周边农田土壤(0~20 cm)为研究对象,监测了Cd、As、Pb、Cr、Cu、Zn、Hg等7种重金属的含量,并对重金属污染程度与潜在生态风险进行了评价。结果表明,7种重金属都存在不同程度的超标或污染,其中Cd、As、Pb等的污染较为严重。统计学分析结果表明,Pb、As、Hg、Zn、Cd等来源相同,可能主要都来自于人为污染,即冶炼作业造成的污染。7种重金属化学形态不尽相同:在重金属有效态中,Cd的水溶态和可提取态较高;Pb、Cu、Zn可还原态、可氧化态这两部分含量较高。而Hg、As、Cr的残渣态含量较高。风险评价代码评价结果表明,Cd的生态风险较高,4.5%的样点Cd为极高生态风险,52.8%的样点Cd为高生态风险,42.7%的样点Cd为中度生态风险;100%的样点Zn为中度生态风险;Cu有60.1%的样点属于低生态风险,39.9%的样点属于中度生态风险;As、Pb主要以低生态风险为主(所占比例分别为77.2%、80%);Hg主要以无生态风险为主(所占94.3%)。Hakanson潜在生态风险指数法计算的综合潜在生态风险指数(RI)的范围为46.4~1 627.5,表明研究区域农田土壤存在很高的生态风险。上述各项结果综合表明,研究区农田土壤受到了严重的重金属污染,由此引起的重金属生态风险应引起高度关注。     

城市土壤重金属污染及其生态环境效应

对城市土壤中重金属的来源、空间分布特征、化学形态、在不同介质间的迁移转化及其污染的生态环境效应等近年来的研究进展进行了回顾,指出今后的研究重点是建立城市土壤重金属污染风险评价和标准体系,并应对重金属在城市环境中的迁移转化机制及城市土壤质量演变与郊区之间的关系开展研究。     

张掖市农田土壤重金属污染分析及防治建议

选择张掖市部分区域农田土壤进行了Hg、Cd等8种重金属元素含量的分析,并采用内梅罗综合指数法和Hakanson潜在生态危害指数法对其土壤重金属污染状况和潜在生态风险进行了评价。结果表明,张掖市农田土壤中Hg、Cd等8种重金属元素的平均含量均低于国家土壤环境质量标准二级标准,但是Cu、Pb、Cd、Cr等4种重金属元素含量的平均值不同程度的超过了张掖市土壤背景值。综合两种评价方法的结果表明,张掖市农田土壤重金属污染的潜在生态风险为轻度生态风险,但是Cd元素的生态风险系数达到中等生态风险,应该引起关注。     

土壤中重金属形态的化学分析综述

土壤中重金属的赋存形态决定其在土壤中的迁移性、生物可利用性以及毒性.土壤中重金属形态的化学分析法是依据不同浸取能力的提取剂分别提取出与土壤颗粒有着不同结合力的化学形态并测定其浓度而建立起来的.文章对土壤重金属形态分析中选用的提取试剂以及分析流程进行了综述,比较了各种试剂和方法的优缺点.同时对形态分析的土壤样品的前处理方式进行了简要概述.     

云南会泽者海镇典型矿区场地重金属污染特征及健康风险评价

选择云南会泽县者海镇矿区重金属污染场地,按不同暴露途径计算土壤中Pb、As、Cd、Zn、Cu、Cr、Hg等金属污染物的风险,并通过风险评价,分析场地内的健康风险水平。结果表明:所有暴露途径中Zn、Cu、Pb对人体健康的平均风险较小。在居住用地情景下,土壤中Cd的综合致癌风险为2. 6×10-5,As的综合致癌风险为3. 3×10-4,场地内As和Cd的污染对敏感受体健康的潜在危害较大。     

钼矿区周边农田土壤中重金属污染状况的分析与评价

对钼矿区周边农田土壤重金属污染情况进行了详细研究.选择该矿区受污染农田土壤样本80个,采用HNO3-HF-HClO4混酸对土壤样品进行处理,运用欧共体参比司推荐的BCR三步连续提取法进行化学形态分析;使用等离子体发射光谱仪(ICP-AES)测定土壤样品中Mo、Pb、As、Hg、Cr、Cd、Zn、Cu、Ni的全量及各种化学形态的含量并进行评价,同时对矿区地下水进行分析;采用spas软件进行数据分析.结果表明,矿山周边农田土壤重金属主要污染物为Cd、Hg并伴有Cr污染;Nemerow综合指数6.81,综合评价结果为该区土壤已受严重污染;Cd与As污染来源基本相同,Cu、Ni、Zn污染来源基本相同,Hg有独立的污染来源;重金属中化学形态分布为残余态>有机结合态>氧化结合态>酸可提取态;重金属Cr及Hg的有效态比例较大,可能会影响农作物的正常生长;矿山周边农田土壤重金属污染的原因可能是污染地下水的浇灌,矿石的开采、运输和大气降尘等过程;有机农药及塑料农用制品的施用过程,自然成土、矿物的伴生及其转化等过程.     

会泽某铅锌矿周边农田土壤重金属风险评价研究

采用现场采样与室内测试方法测定了会泽某铅锌矿周边农田土壤中Cd、As、Pb、Cr、Cu、Zn、Ni的含量,利用地积累指数法、潜在生态指数法对其土壤环境质量进行了评价,并应用US EPA推荐的健康风险评价法对重金属的健康风险进行了初步评价。结果表明,7种重金属均存在不同程度的富集或污染。多种重金属潜在生态风险指数属于中等及以上的风险状态,重金属潜在生态风险指数排序为CdPbAsCuNiZnCr。7种重金属在3种暴露途径下对儿童的非致癌健康风险均大于成人,但对成人、儿童均不存在显著的非致癌健康影响、非致癌健康总风险。As、Ni、Cr、Cd重金属的致癌风险值与4种元素总致癌风险值均未超出10-6~10-4的范围,尚不具备致癌风险。     

基于Hakanson潜在生态风险指数的某垃圾填埋场土壤重金属污染评价

将Hakanson提出的潜在生态风险指数法应用于垃圾填埋场及周边土壤重金属污染评价，扩充了评价因子，确定了各重金属的毒性系数及参比值。研究结果表明，评价区土壤中Hg的潜在生态风险较重，其后依次为Cd、As、Ni、Cu、Pb、Co、Cr、Mn和Zn。对污染场地的风险评估及生态修复有一定的指导意义。     

某铀尾矿库周围农田土壤重金属污染潜在生态风险评价

为能够定量评价铀尾矿库周围农田土壤重金属污染程度及其潜在生态危害性,采用Hakanson潜在生态风险指数法对土壤中重金属进行综合污染评价。结果表明,铀尾矿库周围部分农田土壤中重金属Cd、Ni、As、Cu、Hg、Zn含量存在积累和超标情况,尤以Cd的污染最严重,Ni、As次之;Pb、Cr含量能够满足标准限值要求。潜在生态风险评价结果显示,铀尾矿库周围农田土壤重金属潜在生态风险较高,主要潜在生态风险因子为Cd,其次是Hg、As,Cr、Pb、Ni、Cu、Zn并不构成潜在生态风险。铀尾矿库周围农田土壤中较高水平的Cd在构成环境污染的同时,也构成了较严重的生态危害,应加强对重金属Cd、Hg的生态风险防治。     

薄膜扩散梯度技术在重金属生物有效态监测中的应用

重金属生物有效性是评估重金属元素迁移性、生物可利用性和生态影响的关键参数。薄膜扩散梯度技术(DGT)是一种原位被动采样技术,因其具有原位富集性、形态选择性,可提供被监测物质在监测时间段内的平均浓度等优点,可作为生物对重金属摄取的模拟替代物对环境介质中重金属的生物可利用度进行预测,已被广泛应用于环境介质中重金属生物有效性的测定。研究主要介绍了DGT技术的原理、组成和特点,评述了其近年来在水体、土壤、沉积物中重金属生物有效态应用方面的新进展,提出了DGT技术未来要提高抗生物污染能力及寻找可与DGT技术联用的相关技术的观点。     

Assessment of heavy metals in sediments from a typical catchment of the Yangtze River, China

An intensive investigation was conducted to study the accumulation, speciation, and distribution of various heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in sediments from the Yangtze River catchment of Wuhan, China. The potential ecological risks posed by these heavy metals also were estimated. The median concentrations of most heavy metals (As, Cd, Cr, Cu, Ni, Pb, and Zn) were higher than the background values of soils in Wuhan and were beyond the threshold effect level (TEL), implying heavy metal contamination of the sediments. Carbonate-bound Cd and exchangeable Cd, both of which had high bioavailability, were 40.2% and 30.5% of the total for Cd, respectively, demonstrating that Cd poses a high ecological risk in the sediments. The coefficients of the relationship among Pb, Hg, and Cu were greater than 0.797 using correlation analysis, indicating the highly positive correlation among these three elements. Besides, total organic carbon content played an important role in determining the behaviors of heavy metals in sediments. Principal component analysis was used to study the distribution and potential origin of heavy metals. The result suggested three principal components controlling their variability in sediments, which accounted for 36.72% (factor 1: Hg, Cu, and Pb), 28.69% (factor 2: Cr, Zn, and Ni), and 19.45% (factor 3: As and Cd) of the total variance. Overall, 75% of the studied sediment samples afforded relatively low potential ecological risk despite the fact that generally higher concentrations of heavy metals relative to TEL were detected in the sediments.     

渭河陕西段表层沉积物重金属污染特征及潜在风险

为了解渭河陕西段表层沉积物重金属的污染特征，采用ICP-MS分析了13个采样断面表层沉积物中As、Cd、Cr、Cu、Mn、Ni、Pb和Zn 8种重金属的含量，并对其来源和生态风险进行了评价。结果表明：渭河陕西段8种重金属的平均含量顺序依次为Mn > Zn > Cr > Cu > Ni > Pb > As > Cd；除Ni外的其余7种重金属的平均含量均超过陕西省A层土壤背景值。各断面表层沉积物重金属的潜在生态风险指数（RI）介于111.4~7 043.7，其中23.1%的断面有极强生态风险，46.2%的断面为中等生态风险，其余为轻微生态风险。Cd污染最为严重，对各断面的潜在生态风险介于较强生态风险与极强生态风险之间，对RI的贡献平均为85.2%；其余7种重金属在所有断面均属于轻微生态危害。渭河陕西段表层沉积物As、Cd、Cu和Zn主要为工业与农业来源；Cr和Ni主要为自然来源；Pb和Mn与城市污水和交通污染来源有关。     

Leaching Characteristics of Arsenic and Heavy Metals in Urban Roadside Soils Using a Simple Bioavailability Extraction Test

Regular ingestion of soils could pose a potential health threat due to long-term toxic element exposure. In order to estimate the human bioavailability quotients for As and heavy metals, 12 urban roadside soil samples were collected and analyzed for As, Pb, Cu, Zn, Ni, Co, and Cr using Simple Bioavailability Extraction Test (SBET). The quantities of As, Pb, Cu, Zn, Ni, Co, and Cr leached from soils within the simulated human stomach for 1 h indicated, on average, 27.3, 71.7, 40.4, 59.3, 17.7, 27.2 and 5.6% bioavailability, respectively. Significant positive correlations were observed between the amounts leached using SBET and the total amounts dissolved with HNO₃-HCl-HF acid mixtures. Stepwise multiple regression analysis indicated that the amounts leached with SBET for As, Pb, Zn, Ni, and Co were not related to any of the physic-chemical parameters measured (i.e., soil texture, pH, total organic matter). These results may be valuable for providing input data for risk assessment at sites subject to anthropogenic soil contamination.     

Distribution,bioavailability, and potential ecological risk of Cu,Pb, and Zn in soil in a potential groundwater source area

In this study, we examined three horizontal and vertical soil profiles along a sewage drainage ditch in order to determine the spatial distribution of Cu, Pb, and Zn in soils and to assess the bioavailability and potential ecological risks associated with these metals in a potential groundwater source area. Results showed that the concentrations of Cu, Pb, and Zn were approximately at background level, suggesting that human activities (industrial and agricultural pollution) had a negligible influence on these metals in soil, and that the concentrations reflected the natural background levels in the study area. Cu, Pb, and Zn concentrations were slightly higher in topsoil (0–20 cm) than deeper in the soil profile. Using a modified BCR sequential extraction method to evaluate the mobility and bioavailability of metals showed that the potential bioavailability sequence of Cu, Pb, and Zn at three depths in the soil profile was in the order Cu?≈?Pb?<?Zn. The potential ecological risk from the metals was evaluated using risk assessment code, and the results suggest that Cu and Zn pose no or low risk, while there is a low or medium risk from Pb. Results from groundwater monitoring showed that the groundwater was not polluted by leaching from soil.     

Ecological Risk Assessment of Abandoned Shrimp Ponds in Southern Thailand

The potential ecological risks associated with contaminants from 15 abandoned shrimp ponds in southern Thailand were assessed at the screening level. Shrimp ponds reported as out of production for more than 2 years were selected as sampling sites. The assessment endpoint was identified as the protection of aquatic life from hazard of multiple agents or stressors in water or sediment from the ponds. The measurement endpoints were amount of toxic phytoplankton species, Yellow Head Viruses, SEMB viruses, oxytetracycline, cadmium, copper, and manganese. Data from field measurements and laboratory analyses obtained primarily from April to June 2003 were used in the risk analysis. The results showed that insignificant amounts of stressors were present, except for the metals. So, only concentration values of the metals were used in the calculation of hazard quotients (HQ) for risk characterization. The highest potential ecological risk characterized by the highest HQ value observed for each metal was 19 for manganese, 4.3 for cadmium, and 1.8 for copper. These findings indicated a need for further ecological risk assessment at a more detailed level to focus on the bioavailability and effects of metals from abandoned shrimp farms, with manganese the highest priority.