植物中汞的研究进展

植物生态系统中汞的环境过程是生物地球化学循环过程的重要组成部分，且与整个生态系统中各物种的生存和发展密切相关。本文介绍了植物中汞生物地球化学循环的进展，包括汞对植物的生物毒性、植物中汞的来源、分布与迁移转化、植物大气间汞的交换过程及其研究方法，以及植被在生态系统间汞循环中的重要作用，最后简要介绍今后的研究重点和热点。     

重金属在水环境中形态分布的随机模拟

水环境中重金属的毒性，生物可给性，以及活性均与其存在形态密切相关。而重金属的存在形态是由其容量控制参数决定的。水环境中，重金属的容量控制参数在空间上和时间上发生随机变化。本文的目的在于研究容量控制参数的随机变化对重金属形态分布的影响。作者以洋河汞污染为例，将形态分布模型同Ｍｏｕｔｅ Ｃａｒｌｏ方法相结合模拟了河水中ｐＨ值，有机质浓度，总汞含量，以及悬浮物含量的随机变化对汞形态分布的影响。研究结果表     

北极阿拉斯加春季积雪中汞的时空分布及其来源分析

开展北极雪冰中汞分布特征及其来源的探究,不仅可以丰富冰冻圈汞生物地球化学循环的认识,而且对评估北极环境中汞的潜在暴露风险具有现实意义。在2017年4月至5月对美国阿拉斯加的积雪进行大范围样品采集,探讨了该区域积雪中汞的空间分布特征及其成因、汞的沉降后过程以及潜在来源分析。研究表明：积雪中汞的空间分布受大气汞亏损事件（AMDEs）及人为源的共同影响,毗邻北冰洋海岸（如巴罗）积雪中总汞（THg）浓度较高,接近人为源的山地表层雪中THg浓度较高。巴罗雪坑中THg浓度随深度增加呈下降趋势。积雪中主要阴阳离子与THg的相关性分析表明,阿拉斯加积雪中THg的空间分布可能主要受北冰洋海盐气溶胶以及人类活动的影响。     

土壤中汞存在形式的研究

本文运用部分连续萃取不同地球化学相的化学分析方法，对高汞区，人为汞污染区和背景参考区五个采样点土壤样品的七种汞形态进行了分析，研究表明，人为汞污染和地质作用都会造成土壤中汞的富集，但这两类土壤中汞的相态分布有明显的差别。     

百花湖沉积物剖面中汞的空间分布

贵阳百花湖长期受汞法生产醋酸企业含汞废水的污染,沉积物及其孔隙水均受到严重的汞污染,总汞含量远远高于背景区.我们研究了汞污染企业停排后,百花湖沉积物剖面中汞污染程度、水平和垂直分布特征.研究显示,汞的垂直分布呈现表层和底层含量较低,中层出现峰值的分布趋势,沉积物中总汞的最高含量达到38 mg/kg(干重),且这种分布趋势恰好与贵州有机化工厂的生产历史相对应,反映了百花湖汞污染主要来源于该厂.百花湖表层沉积物中总汞的含量逐步下降,但在上游沉积物中总汞含量仍约为背景区总汞含量的40倍左右,离污染源较远的下游逐渐减少到背景区的3倍左右.这表明百花湖的汞污染在逐渐减轻,沉积物中大量的汞的扩散和再悬浮对上覆水体、鱼类和其他水生物具潜在的危害性.     

汞矿区稻田土壤汞形态分布特征及对甲基化的影响

汞污染区稻米甲基汞超标现象普遍存在,汞在土壤中的形态分布被认为是影响甲基化过程的重要因素之一.本研究选取贵州省万山废弃汞矿区和土法炼汞区为研究区域,在水稻生长期间对稻田土壤剖面中总汞、甲基汞及形态汞进行测定,结合土壤环境因子指标,讨论土壤汞形态分布特征对甲基化的影响.研究表明,汞矿区稻田土壤中总汞和甲基汞均表现出随土壤深度加深而逐渐降低的趋势,且主要以有机结合态和残渣态形式存在,占总汞的98％以上.在废弃汞矿区,不同形态汞可能会转化为生物难以利用的形态:溶解态与可交换态、特殊吸附态与氧化态汞可能先转变为有机结合态,再转变为残渣态汞.在土法炼汞区表现为硫酸盐还原与铁还原过程驱动的汞甲基化过程,并且有机结合态汞可能也参与了甲基化过程.     

压汞实验对低阶煤表征的适用性分析及校正方法

压汞实验在中-高阶煤的孔隙测试中得到了广泛的应用。然而对于低阶煤，由于其煤体疏松、易碎，压汞的增压过程会造成孔隙结构破坏，导致实验结果不准。为了准确评估压汞实验对低阶煤孔隙结构的损伤，选取褐煤和长焰煤为研究对象，同时利用压汞与核磁共振测试煤的孔径分布。结果表明，压实与凝胶化程度低的褐煤和长焰煤，压汞测试过程破坏了其大中孔的原生结构，从而导致中孔比例升高；同时受基质压缩效应影响导致微孔体积偏高。随着煤化作用增强，长焰煤较褐煤所受的影响逐渐减小。进一步通过氮气吸附实验对压汞高压段的测试结果进行校正，以消除基质压缩效应引起的煤体弹性变形所带来的误差，其中，褐煤压汞校正前测试误差为87%，而校正后仅为18%。实验研究表明，联合利用核磁共振测试、氮气吸附实验可显著提高压汞法用于低阶煤孔隙测试结果的准确性。      

汞气测量在陕西韩城春秋古墓中的应用

采用汞气测量方法对陕西韩城春秋古墓的位置、被盗情况进行勘查与判断。在墓区及外围,对已开挖墓穴不同部位的空气、壤中气和土壤热释汞分别进行测量,证实了古墓葬中存在高浓度的气汞、壤中气汞和土壤热释汞异常,并利用汞异常的分布形态和位置确定了古墓位置和盗洞位置。     

城市汞污染土壤中Hg的形态特征

介绍了我国13个城市及其周边地区汞污染土壤中汞的形态特征研究成果。通过对汞污染土壤化学分析、形态分析、热释汞研究、重矿物研究发现,我国城市汞污染土壤中HgS是Hg的主要存在形态,13城市汞污染土壤重矿物研究中辰砂的大量出现及其含量与分布特征也进一步佐证了这一结论。汞污染土壤中汞污染程度越高,HgS含量越高,辰砂出现几率越大,且含量越高。该成果对我国汞污染调查研究和汞污染土壤生态地球化学环境评价具有重要的理论价值和实际意义。     

植被生态系统汞的生物地球化学循环研究进展与挑战

汞是联合国环境规划署重点管控的全球性污染物.植被是联结大气圈与土壤圈的关键纽带,在全球汞生物地球化学循环中扮演着举足轻重的角色.植被生态系统是全球大气重要的汞汇,但由于大气?植被?土壤的汞界面交换过程及植物组织中汞的分布、来源与迁移转化规律及驱动机制认识不清,致使当前的全球汞生物地球化学循环模型缺失植被过程模块,无法厘定全球植被的大气汞汇通量.近年来迅速发展的汞同位素地球化学、同步辐射和微气象汞通量观测等新方法,为多层次解析不同类型植被与土壤及大气界面汞交换过程,阐明植物组织中汞的分布、来源与迁移规律提升了可能,能为进一步解决当前森林生态系统汞的生物地球化学循环的研究难点提供独辟蹊径的视角.      

Concentration,distribution and bioaccumulation of mercury in the Xunyang mercury mining area,Shaanxi Province,China

Samples of surface water, soil, sediment and plants from the Xunyang Hg mining area in Shaanxi Province, China, were analyzed to assess the effects of the Hg mining activities on the environment. The results show that: (1) the mining activities are sources of Hg to the environment surrounding the mine; (2) the environment, especially riverbeds in the Xunyang area, is contaminated with Hg and (3) Hg accumulation in cabbage leaves, the main vegetable for the local residents, is high, reaching concentrations that are 6–540 times higher than the maximum Hg concentration recommended for edible plants in China. Action should be taken to remediate contaminated sites, manage waste discharges and reduce the exposure of Hg to local residents by issuing advisories against consuming agricultural products grown in the area, which are contaminated with Hg.     

Impact of human activities on the central Mediterranean offshore: Evidence from Hg distribution in box-core sediments from the Ionian Sea

Total Hg concentrations have been measured for five box-core sediments collected seawards of the Augusta industrial area (SE Sicily). In more coastal sediments, upcore increasing Hg concentrations, exceeding the Hg background concentration estimated for the Strait of Sicily, indicate Hg contamination over time due to the industrial area development. Strong correlation between total organic C (TOC) and Hg concentrations was found only for core BX2, that displays organic C to total N (C/N) ratios indicative of autochthonous organic matter. For other sediments, high Hg enrichment factors with respect to TOC indicate, in addition to Hg trapping by TOC, other factors as responsible for Hg accumulation. In the presence of some contribution of detrital organic matter, Hg is mainly adsorbed onto the mineral component of the bottom sediments probably because TOC is saturated by Hg excess. Contaminant impact affected also the open sea environment. Main drivers of Hg flux towards the offshore were dredged materials, which repeatedly discharged sediment, resulting in substantial increases in TOC contents and high C/N ratios. Consistent with the geochemistry of recent turbidites, these anomalous sedimentary inputs induced sediment redox environment modifications, constrained by Mn peaks, which affected Hg distribution.     

运用地球化学调查数据研究银川盆地土壤环境污染程度

重金属元素及其他元素在土壤圈中长期积累到一定程度后会对环境造成影响并对食物链产生危害,对土壤进行元素的污染程度划分有助于及时掌握土壤环境现状。运用多目标区域地球化学调查数据,将Hg、Cd、As、Pb、Cu、Zn、Ni、Cr等8项重金属元素按照土壤环境质量一级标准值、F元素一级推荐值,分别采用尼梅罗公式计算其污染指数,绘制污染程度图。将银川盆地划分为清洁区、基本清洁区、初始污染区、轻度污染区、中度污染区和重度污染区,并分析总结了污染来源。     

Distribution and speciation of mercury in soil in the area of an ancient mercury ore roasting site,Frbejžene trate (Idrija area,Slovenia)

In the initial period of mining activities in the Idrija basin (the16^th and the first half of the17^th centuries), Hg ore processing was performed at various small-scale roasting sites in the woods surrounding Idrija, by roasting ore in earthen vessels. The recovery rate of this method was very low; about half of Hg was lost, causing soil contamination and considerable amounts of waste material that could potentially leach Hg into the surrounding environment. The main aims of present geochemical study were to determine the contents, vertical distribution and speciation of Hg in soils at the roasting site at Frbej?ene trate in order to verify the extreme pollution of ancient Hg ore roasting sites in the Idrija area and to establish their significance in the wider spatial contamination of soils and aquatic systems. Soil sampling was performed at the area of the former roasting site. The organic matter-rich surface soil layer (SOM) and underlying mineral soil were sampled at 63 sampling locations. Mercury speciation was performed using Hg thermo-desorption-AAS to distinguish cinnabar from potentially bioavailable forms. The results indicate extremely high Hg concentrations with a maximum of 37,000 mg/kg in SOM and 19,900 mg/kg in mineral soil. The established Hg median in soil was 370 mg/kg and in SOM 96.3 mg/kg. Spatial distributions of Hg in SOM and soil showed very high Hg contents in the central area and decreased rapidly with distance. The results of Hg thermo-desorption measurements indicated the presence of cinnabar (HgS) and Hg bound to organic or mineral soil matter. A significant portion (35–40%) of Hg in the investigated soil and SOM samples was comprised of non-cinnabar compounds, which are potentially bioavailable. It has been shown that soils contain high amounts of potentially transformable non-cinnabar Hg, which is available for surface leaching and runoff into the surrounding environment. Therefore, contaminated soils and roasted residues at the studied area are important for persistent Hg release into the aquatic ecosystem.     

The geochemical characteristics of mine-waste calcines and runoff from the Wanshan mercury mine,Guizhou, China

Mercury and other geochemical parameters were measured in mine-waste calcines, stream sediments and surface waters from the Wanshan Hg district in the Guizhou Province of China to evaluate adverse effects of Hg to the surrounding environment. Wanshan ore is dominantly cinnabar, and lacks other sulfide minerals and as a result, heavy metals other than Hg are rare in the calcines and mine-water runoff. Host rocks in the Wanshan area are dominantly carbonates, which upon weathering, produces alkaline-water runoff. Surface waters emanating from calcine piles have water pH varying from 10.6 to 11.8, contain high EC values, and variable major element geochemistries. Dissolved Hg concentration decreases from 300 to 1900 ng/l in mine water to 72 ng/l in stream water collected significantly downstream from the mine. High concentrations of Hg in mine-waste calcines and alkaline surface water are the major threats to the surrounding environment. Alkalinity is also naturally attenuated downstream from the Wanshan mine. However, erosion and transport of Hg in sediment and water and highly alkaline mine-water runoff, may adversely affect sediment, aquatic and biological columns downstream from the Wanshan mine area.     

Environmental impact of ancient small-scale mercury ore processing at Pšenk on soil (Idrija area, Slovenia)

The Idrija mine was the second largest Hg mine in the world surpassed only by the Almaden mine in Spain. It has been estimated that almost 145,000 tons of Hg was produced during operation (1490-1995) of the mine. In the first decade of Hg mining in Idrija the ore was roasted in piles; after that it was roasted for 150 years, until 1652, in earthen vessels at various sites in the woods around Idrija. Pšenk is one out of 21 localities of ancient roasting sites established on the hills surrounding Idrija and one of the largest localities of roasting vessel fragments. The unique way of roasting very rich Hg ore at this site has resulted in soil contamination and considerable amounts of waste material that potentially leach Hg into the surrounding environment. The main aim of this study was to determine the distribution and the forms of Hg in contaminated soils in order to evaluate potential environmental risk. Detailed soil sampling was performed on 37,800 m² area to establish the extent of Hg pollution and to investigate Hg transformations and transport characteristics through the 400 a-long period. A total of 156 soil (0-15 cm and 15-30 cm) and SOM (soil organic matter) samples were collected from 73 sampling points. Three soil profiles were sampled to determine vertical distribution of Hg. The main Hg phases were determined by the Hg-thermo-desorption technique. The measured Hg contents in soil samples in the study area vary from 5.5 to almost 9000 mg/kg with a median of 200 mg/kg. In SOM, Hg contents range from 1.4 to 4200 mg/kg with a median of 20 mg/kg. Extremely high Hg contents were found in soil profiles where the metal reaches 37,020 mg/kg. In general, Hg concentrations in all three profiles show a gradual decrease with depth with the minimum values between 140 mg/kg and 1080 mg/kg. The Hg-thermo-desorption curves indicate the presence of Hg in the form of cinnabar and that of Hg bound to organic or mineral soil matter. The distribution of Hg species in soil and SOM samples show almost equal distribution of cinnabar and non-cinnabar Hg compounds. The non-cinnabar fraction shows a little increase with depth, but cinnabar represents a high portion of total Hg (about 40%). Large amounts of potentially mobile and transformable non-cinnabar Hg compounds exist at the roasting site, which are potentially bioavailable.     

承德中部土壤-黄芩系统重金属生物有效性及迁移累积特征

土壤重金属含量是影响黄芩产量和质量的重要因素。选取承德市中部金沟屯和五道岭两处黄芩种植示范区为研究区,采集表层土壤样品355件,黄芩样品30件,重金属形态样品15件。在分析土壤Mn、Zn、Cu、Cr、Cd、As、Pb、Ni、Hg、V、Co、Sb和土壤有机质含量（SOM）及pH值,黄芩Zn、Cu、Cr、Co、Cd、Pb、Ni、Hg和As含量基础上,采用描述性统计、地累积指数、主成分和RDA分析、重金属生物富集系数、生物活性系数和迁移系数等方法论述了土壤-黄芩系统重金属生物有效性及迁移累积特征。结果表明:金沟屯和五道岭区土壤各重金属累积程度总体属无-中度累积水平。五道岭Cu和Hg累积程度高于金沟屯区,其它元素累积程度低于金沟屯区。五道岭区表层土壤Cr、Cu和Cd含量超标率分别为2.82%、1.69%和1.13%;金沟屯区土壤Cd、Cr和Ni,五道岭区土壤Zn和Hg含量超标率均为0.56%。五道岭区黄芩Cu元素含量高于金沟屯区,Co和Cu元素生物富集强度高于金沟屯区,其它元素含量和生物富集强度则均低于金沟屯区。土壤Cd和Hg元素生物活性系数相对最高,Ni、Zn和Pb元素次之,Cu、Cr和As生物活性系数相对较低。金沟屯区根系土具有较低的pH值和较高的SOM含量,区内黄芩根部As、Cd、Cr、Ni、Zn和Pb元素BCF平均值高于五道岭区,Cu元素富集强度低于五道岭区。土壤重金属生物有效性和黄芩重金属生物富集强度受土壤pH和SOM含量影响,其中Cd和Cu元素受SOM含量影响最为明显。     

Mercury contamination and its potential health effects in a lead-zinc mining area in the karst region of Guangxi, China

Mercury contamination of the environment is of worldwide concern because of its global presence and its potent neurotoxicity. Mining, smelting and the electronics industry are the main sources of Hg pollution. However, few studies have been performed to investigate systemic Hg contamination in metal mining regions. In this study, concentrations of Hg in air, farmland soil, and crops were measured in a Pb-Zn mining area in the karst region of Guangxi, China. Key factors that could affect Hg distribution, such as the fate of waste ore and waste residue, were analyzed. Geo-statistical methods were adopted to analyze the characteristics of spatial structure and distribution of Hg. The results show that Hg contamination in this region is serious. The total mercury (T-Hg) content is far higher than the Level II Limit Value of Chinese Soil Standards of 0.30 mg kg⁻¹, showing obvious directional characteristics from WNW to ESE. Highest Hg concentrations were found in the WNW portion of the study area. The contamination of paddy soil is higher than that in dry farmland soil. The vertical distribution of T-Hg and its decrease with depth suggest that the important sources are waste water irrigation and the improper disposal of the waste ore and waste rock. The T-Hg concentrations in the agricultural products examined exceed the Chinese tolerance value (0.02 mg kg⁻¹ for rice and 0.01 mg kg⁻¹ for vegetables), indicating the seriousness of the problem. The ecological environment and the safety of food grown in this mining area are being affected, with the result that human health is possibly being affected.     

Farmland mercury contamination in the vicinity of an organic chemical factory in Guizhou,China

This study assesses the level of contamination of Hg in farmland soils along the irrigating channel downstream from Guizhou Organic Chemical Factory （GOCF）, where metallic mercury is used as a catalyst to produce acetic acid. The total input of mercury into the environment, as announced by GOCF, is 140 t in the past 30 years （1971-2000）. Sampling sites were chosen based on the distance from the source of pollution--the chemical factory. A total of 39 samples were collected from the study area and analyzed for total mercury concentrations and methyl mercury concentrations. The characteristics of vertical and horizontal distributions of total mercury and methyl mercury in the study area （farmland） are described in this paper. Much attention was paid to the transformation of inorganic Hg into organic mercury species in soils as well. The results showed that the farmland has been heavily contaminated by Hg. Land cultivation activity, land utilization style and distance from the pollution source could be the dominant factors controlling the distribution of THg and MeHg. It is observed that active transformation of inorganic Hg into organic mercury species （MeHg） usually takes place in paddy soils.     

山东省乐陵—河口地区重金属污染现状与分布迁移规律

对山东省乐陵—河口地区重金属元素的分布迁移规律进行研究,结果表明,研究区土壤以清洁型为主;污染区土壤轻度污染所占比例最大,中度及重度污染占研究区的0.57%,污染因子主要为Cd、Hg、Pb,工业废水是土壤污染的主要来源。Cd、Hg在污染区小麦秸杆中明显富集,接近或超过其根系土中的含量,在籽实中含量最低,小麦籽实中Se、Zn明显富集。土壤根系土中Cd、Hg等以稳定态分布为主,活动态的含量很低,活化迁移量少,这与区内碱性环境密切相关。