Seasonal distribution and speciation of mercury in a gold mining area,north-west province,South Africa

The seasonal speciation of mercury (Hg) was determined in water, soil, and sediments from watersheds located in the North-West province of South Africa. The study area is known to have a long history of mining activities which also include the recovery of gold from old tailings. Both inorganic (IHg) and methyl mercury (MHg) were detected at high concentrations (up to 8480 μg IHg kg^?1 and 13 μg MHg kg^?1) in surface sediments during dry season. A considerable remobilization of Hg from bottom sediments was observed in water from dry to wet season as well as the migration of Hg away from pollution sources due to seasonal influences. Hg in sediments mostly has been speciated as Hg⁰. Enhancement of Hg methylation occurred mainly in deeper sediments at regions corresponding to the lowest redox potential, higher pH, and enrichment of IHg. Hg values in borehole waters were very high (up to 3310 ng L^?1) suggesting a serious contamination of the site groundwater which needs to be addressed urgently in order to minimize further impact that affects the Vaal River and other water systems located nearby.     

环境中汞化学形态分析研究进展

作为一种剧毒元素,汞的毒性与其化学形态密切相关.环境介质中汞的化学形态监测分析主要涉及样品的采集、保存、前处理、分离和测定等步骤.本文综合国内外相关文献,系统介绍了开展环境介质中汞化学形态监测分析的相关测试技术和方法,并阐述了我国开展汞化学形态监测存在的问题及其意义.     

An Operationally Defined Method to Determine the Speciation of Mercury

This paper presents a modified method of an operationally determined speciation of mercury in soil. The analytical work was mainly concerned to suit properly with inductively coupled plasma-atomic emission spectrometry (ICP-AES). Soil samples analysed in this study were selected from open areas around a crematorium, a waste incinerator, and two power plants. Results show that both topsoil and subsoil samples were dominated by elemental mercury Hg(0) and mercuric sulphide (HgS). The significant correlation between sulphur concentration and HgS was found in topsoil samples.     

Principal Biogeochemical Factors Affecting the Speciation And Transport of Mercury through the terrestrial environment

It is increasingly becoming known that mercury transport and speciation in the terrestrial environment play major roles in methyl-mercury bioaccumulation potential in surface water. This review discusses the principal biogeochemical reactions affecting the transport and speciation of mercury in the terrestrial watershed. The issues presented are mercury-ligand formation, mercury adsorption/desorption, and elemental mercury reduction and volatilization. In terrestrial environments, OH^–, Cl^– and S^– ions have the largest influence on ligand formation. Under oxidized surface soil conditions Hg(OH)₂, HgCl₂, HgOH⁺, HgS, and Hg⁰ are the predominant inorganic mercury forms. In reduced environments, common mercury forms are HgSH⁺, HgOHSH, and HgClSH. Many of these mercury forms are further bound to organic and inorganic ligands. Mercury adsorption to mineral and organic surfaces is mainly dictated by two factors: pH and dissolved ions. An increase in Cl^– concentration and a decrease in pH can, together or separately, decrease mercury adsorption. Clay and organic soils have the highest capability of adsorbing mercury. Important parameters that increase abiotic inorganic mercury reduction are availability of electron donors, low redox potential, and sunlight intensity. Primary factors that increase volatilization are soil permeability and temperature. A decrease in mercury adsorption and an increase in soil moisture will also increase volatilization. The effect of climate on biogeochemical reactions in the terrestrial watershed indicates mercury speciation and transport to receiving water will vary on a regional basis.     

九龙江河口潮间带表层沉积物汞污染分布、赋存形态与生态风险

研究九龙江河口汞污染情况可为该地区汞污染防治提供科学依据,测定九龙江河口潮间带表层沉积物中总汞含量及不同形态汞的含量,分析了汞的分布特征、赋存形态及生物有效性和潜在生态风险。结果表明:九龙江河口潮间带表层沉积物中总汞含量范围0.112~0.259 mg·kg-1,平均值0.172 mg·kg-1,部分采样点汞含量超过中国海洋沉积物质量第一类标准限值(0.20 mg·kg-1);沉积物中各形态汞平均比例顺序:残渣态(61.8%)可氧化态(27.8%)弱酸溶态(7.8%)可还原态(2.6%),可提取态占有相当的比例,对水体汞污染具有一定贡献。潜在生态风险指数法评价结果可知,该河口区潮间带沉积物中汞污染程度和生态风险程度均为中等~较高水平,需对汞污染进行综合防治。     

环境样品中汞形态分析技术的进展

汞的毒性、环境行为、生物有效性不仅跟其浓度有关,还决定于其化学形态,因此汞的形态分析在环境科学中具有重要意义。样品前处理几乎是汞形态分析研究中不可或缺的步骤,而色谱和光谱/质谱联用技术是目前普遍采用的分离检测方法。文章对近十年来这些方面的研究进展进行了综述,主要包括样品的前处理方法如酸/碱溶剂萃取、微波辅助萃取、固相萃取、固相微萃取、单滴微萃取、分散液液微萃取等,以及色谱（液相色谱、气相色谱）和毛细管电泳与光谱/质谱（紫外可见光谱、原子吸收光谱、原子荧光光谱、等离子体质谱等）的联用技术在汞化合物形态分析中的应用情况。最后提出今后应重点研究建立高效、简便的前处理方法,发展高分离度、高灵敏度、高速度的分离检测联用技术,以便更好地对汞的形态进行分析监测。     

环境样品中汞形态分析技术的进展

汞的毒性、环境行为、生物有效性不仅跟其浓度有关,还决定于其化学形态,因此汞的形态分析在环境科学中具有重要意义。样品前处理几乎是汞形态分析研究中不可或缺的步骤,而色谱和光谱/质谱联用技术是目前普遍采用的分离检测方法。文章对近十年来这些方面的研究进展进行了综述,主要包括样品的前处理方法如酸/碱溶剂萃取、微波辅助萃取、固相萃取、固相微萃取、单滴微萃取、分散液液微萃取等,以及色谱(液相色谱、气相色谱)和毛细管电泳与光谱/质谱(紫外可见光谱、原子吸收光谱、原子荧光光谱、等离子体质谱等)的联用技术在汞化合物形态分析中的应用情况。最后提出今后应重点研究建立高效、简便的前处理方法,发展高分离度、高灵敏度、高速度的分离检测联用技术,以便更好地对汞的形态进行分析监测。     

Speciation study of lead and manganese in roadside dusts from major roads in Ile-Ife,South Western Nigeria

A speciation study of Pb and Mn in roadside dust along major roads in Ile-Ife, South Western Nigeria, was investigated. Pb and Mn values obtained by total digestion ranged from 22.23 ± 3.52 to 43.48 ± 3.05 μg/g and 35.93±0.15 to 83.76 ± 0.06 μg/g, respectively. The results of speciation analysis of Pb and Mn in the samples showed that the mean levels of these metals in the various fractions followed the order: organic matter>residual>Fe-Mn>carbonate>exchangeable and organic matter-bound>exchangeable>carbonate-bound>residual>Fe-Mn oxide-bound respectively. The speciation study therefore revealed that most of the Pb and Mn were associated with the organic matter fraction and that they were least available in the exchangeable and Fe-Mn oxide fractions, respectively. The apparent mobility and potential bioavailability for these metals in the road dust was Mn>Pb. There is a significant difference between the means of Pb and Mn in the road dust of the study area at p≤0.05, which strongly suggests that they may not have come from the same source; different sources may be responsible, which may be anthropogenic, such as tyre wear, vehicular emission, brake linings and natural.     

Inorganic mercury pharmacokinetics in man: a two-compartment model

Excreta data obtained from five human subjects and previously analyzed as part of a multicompartment model (Hall, L.L., P.V. Allen, H.L. Fisher, and B. Most. 1995. The kinetics of intravenously administered inorganic mercury in humans. In Kinetic models of trace element and mineral metabolism, ed. K.N.S. Subramanian and M.E. Wastney, 1-21. Boca Raton: CRC Press) were reanalyzed by means of a two-compartment model. The mobile compartment represents mercury of any form that is available for transport throughout the body. The immobile compartment represents mercury in forms that are not available for transport. The model simulates time profiles for body inorganic mercury and for fecal and urinary excretion. According to the model, intravenously administered mercury enters the body in the mobile form. Following administration, two distinct kinetic profiles were observed. In four of five subjects, mobile mercury in the body declined rapidly and the immobile form became dominant within 6 days. In these subjects, fecal excretion profiles were characterized by an initial phase dominated by excretion of mobile mercury lasting up to 6 days. This was followed by a slower phase during which mobile and immobile mercury were excreted in varying amounts. A similar pattern was seen in urinary profiles, but the initial phase is shorter and less pronounced. In each of these subjects, immobile mercury accounted for 84–94% of the total cumulative urinary excretion. The fifth subject showed a unique kinetic profile. Conversion of mobile to immobile mercury was slow and the two forms did not reach equivalence until approximately 70 days after dosing. Despite this fact, approximately 99% of fecally excreted mercury and 100% of urinary mercury originated in the immobile compartment. Possible explanations for the different profiles are discussed within the context of the model.     

A review of mercury contamination in marine fauna in Thailand

Mercury (Hg) is a ubiquitous environmental toxin that produces a wide range of adverse health effects in humans. Bioaccumulation of mercury in the aquatic food chain is a public concern for many countries. The aim of this study was to review the prevalence of Hg contamination in marine fauna in Thailand.     

不同消解方法对土壤样品中汞含量测定的影响

利用欧洲标准样品，对比研究了3种不同消解方法测定表层土壤中总汞的差异。结果发现，利用(1)王水电热炉加热消解和(2)浓硝酸、浓硫酸及高锰酸钾水浴加热消解的方法测得的标准样的总汞最为接近实际值。而(3)硫酸(1：1)与高锰酸钾水浴加热消解法的测得值明显偏低，但方法3测得的土壤总汞值介于方法1和方法2之间；综合考虑各种因素，方法3测得的土壤总汞仍然有效。文章同时讨论可能影响总汞测定值的因素。     

断裂带中汞的地球化学特征

汞是揭示构造活动及强震孕育机制的重要化学示踪元素.研究断裂带中汞及其同位素,可以示踪地震断裂带汞异常来源、汞的迁移路径,从而揭示流体在地震孕育中的作用.本文总结了汞的观测技术,断裂带岩石、土壤和地下水中汞的特征,概述了汞同位素技术在深部断裂带研究中的进展,以及汞在地震监测和活断层探测方面的应用.断裂带中汞的研究,将有助于厘清汞-深部流体-构造活动-地震的可能关系及其机制,对提升汞在地震监测预测中的研究水平具有重要的理论意义和应用价值.     

铜陵矿区土壤中镉存在形态及生物有效性

采取Tessier连续提取法，研究铜陵矿区不同功能区表层土壤中镉的化学形态分布和生物有效性。结果表明，各种土壤中的镉含量全部高于地区背景值，主要来源与矿业活动有关，部分样品还有矿体的风化富集叠加，土壤镉污染指数PCd为1．15～79。镉含量依次为矿体风化土壤→废矿堆下垫土→市郊菜地土→矿区铜草土、路边土和稻田土→其它土壤。其形态分布，酸性土壤中以Fe-Mn氧化态和可交换态为主，其余三态相对较低；碱性土壤中有机态和残渣态比例较高，碳酸盐态和可交换态所占的比例低。土壤中生物可利用态镉的含量较高，占土壤总镉的60．20%-98．3％，生物不可利用态仅占1．7％-39．2％。     

板蓝根水煎液中13种金属元素形态分析

利用电感耦合等离子体-质谱仪（ICP-MS）测定板蓝根原药材和水煎液中13种元素的含量。形态研究采用高速离心和滤膜分离水煎液中的溶解态和颗粒态,元素的溶解态再用树脂XAD-4、树脂D001、树脂D301和树脂D751分别区分非极性吸附态、阳离子交换态、阴离子交换态和螯合吸附态。结果表明,板蓝根药材含有微量Cu、Pb和Cd等重金属,同时含有丰富的Mg、Ca、Fe、Al等大量元素,其中Ca含量最高,为2739 mg·kg-1;Zn、Mg、Ca、Mn、Al和Fe的浸出率较高,在42.9%到81.9%之间;Pb和Cu的浸出率最低,只有10%左右。Zn、Mg、Ca、Mn和Pb元素颗粒态比例在0%到9.3%之间,其他元素颗粒态比例在14.3%到85.7%之间。在溶解态当中,所有元素都具有阴离子交换态;Cu、Sn、Cr和Al没有或者很少有阳离子交换态,其余元素的阳离子交换态在32.4%到98.3之间;Al、Fe、Cu、Cr和Sn没有或者很少螯合吸附态,其余元素在54.9%到98.4%之间;Zn、Cu、Sn、Cd和Pb有非极性吸附态,其余元素没有。     

Speciation of heavy metals in Albanian coastal sediments

This article presents results on heavy metal (Fe, Mn, Cr, Ni, Cu, Cd, Pb and Zn) speciation in the coastal sediments of Albania. Sediment samples were collected within the framework of the activities of the Interreg Italia–Albania Project, carried out in the Southern Adriatic Sea in 2000–01. This study shows that Albanian coastal sediments are highly influenced by river input, as the decreasing concentrations from coast to offshore confirm. Pb represents an exception of the general trend; meteoric inputs are prevalent for this metal. Ni, Cr, Fe, Zn and Cu correlate significantly and positively in the entire area, indicating a common origin for these metals in the analyzed sediments. All metals result mostly associated to the most refractory phases, which constitute up to 80% of the total concentration. Nevertheless a recent input of Cr, Ni, Cu and Mn can be observed, as the result of mining and industrial activities, in some selected areas, such as the Drin Bay and Durres. Their high concentration in the bioavailable phase can determine toxic effect upon biota.     

外加镍在土壤中的形态与再分配

镍处理土壤经室内培养12周后,采用连续提取技术对试验土壤中镍的形态与再分配方式进行了研究。研究结果表明,外加的水溶性镍进入土壤后的主要存在形态与添加的剂量有关:低剂量时,以铁锰氧化态为主,这一形态在100mg·kg-1处理土壤中占比例最大,达到31.6%;高剂量时,以交换态为主,这一形态在1600mg·kg-1处理土壤中占比例最大,达到48.4%。随着镍添加剂量由0(对照)增加到1600mg·kg-1,再分配系数逐渐由1.00增大到30.65;金属结合强度系数则由0.90减小至0.25,也反映出进入土壤中镍的剂量较大时,镍是以不稳定的形态占优。试验结果也证实了土壤具有减小镍的环境危害的作用,但这种缓冲能力是有限的。随着时间的推移,镍的形态会继续发生变化,但这一转化过程是缓慢的。因此,一旦土壤发生重金属污染,其对土壤环境的影响将是长期的。     

Assessment of air pollution by mercury in South African provinces using lichens Parmelia caperata as bioindicators

Environmental Geochemistry and Health - Large-scale assessment of atmospheric air pollution by mercury (Hg) using lichen Parmelia caperata as biological indicator was undertaken using samples from...     

Distribution of mercury in the atmosphere over Idrija, Slovenia

Idrija mine, the second largest mercury mine in the world, was in use since 1490. More than 107 000 tons of Hg were produced in its five centuries of history until 1990 when production was reduced to a few hundred kilos per year. The average recovery rate of mercury has been estimated to 73%; much of the remaining 27% was dissipated into the environment. In spite of present minimal levels of production, and only a few days of smelter operation per year, a real time survey with a mercury Zeeman analyser in a car showed relatively high mercury concentrations in the air. Amounts of 300--4000 ng Hg ^m-3 have been found around both the major sources of mercury vapour, the smelter and mine ventilation shaft -- while the amounts at the Old Place, at the City Museum, and near the Nikova-Idrijca confluence are of the order of 50 ng m^-3. Polluted air will be transported from those sources to a degree which depends on the weather conditions, mainly the direction and intensity of the wind. The high mercury contents in the air are not only due to anthropogenic sources (smelter and the ventilation shaft, dumps and smelter slag used in construction), but may also partly be natural as in the Pront area, where the outcropping bedrock contains native mercury.     

沿海和内陆地区居民汞暴露量对比

通过对沿海和内陆居民食用水产品消费情况调查以及居民头发汞含量的分析,对不同地区普通居民的汞暴露水平进行了对比研究.居民水产品的消费情况采用调查问卷的形式,对沿海地区大连和内陆地区河南两地普通居民进行了随机调查,并同时采集被调查者的头发作为汞暴露情况的生物样本.本次研究共收集到有效调查问卷及头发样本213份(大连112份;河南101份),两地居民水产品消费量分别为:大连104 g.d-1,河南74 g.d-1;收集到的头发样本采用DMA-80测汞仪(按美国EPA-7473的方法)进行总汞含量的测定.头发总汞含量分析结果显示,大连为(0.363±0.256)μg.g-1,河南地区为(0.192±0.167)μg.g-1.两地区对同一年龄段居民发汞水平比较发现,大连地区居民发汞水平明显高于河南地区.以美国环境保护署(EPA)参考剂量1μg.g-1作为发汞基准,大连地区的超出比例为3%,河南地区的超出比例为1%.该研究结果为了解我国普通居民的汞暴露情况以及后续的汞暴露风险的定量计算提供了基础数据.     

大气汞氧化还原过程与机制的计算化学研究进展

大气中汞的氧化还原反应对于其全球生物地球化学循环起着极其重要的作用,它促进了汞在全球范围内的扩散.汞主要以气态元素汞的形态释放到大气中,并经历复杂的均相和非均相化学反应,被氧化为活性气态汞和颗粒态汞;同时,活性气态汞也可经过光致还原反应光解生成气态元素汞.计算化学是一种基于理论方法利用计算软件来对化学现象和本质进行解释...