Determination of Trace Levels of Mercury in Effluents and Wastewaters

Abstract

Concern about mercury pollution of the environment and the inapplicability of natural water methods necessitated development of a procedure for determining parts per billion mercury in effluents and wastewaters containing large amounts of organic matter. The sample is digested with sulfuric and nitric acids to destroy the organic matter, and the ionic mercury is reduced to the elemental state by stannous ion. Then the digestate is aerated with a stream of air to carry the mercury vapor through a heated line into a quartz cell positioned in an atomic absorption spectrophotometer for measurement. Analyses of effluents and aqueous samples gave good recoveries of added mercury. Effluents, wastewaters, water supplies and aqueous samples secured within manufacturing plants have been analyzed. With minor modification, the procedure has been applied to manufacturing materials such as vinylpyri-dine, latex, sizing, dyes, caustic, and hydro.     

Determination of Trace Levels of Mercury in Effluents and Wastewaters

Concern about mercury pollution of the environment and the inapplicability of natural water methods necessitated development of a procedure for determining parts per billion mercury in effluents and wastewaters containing large amounts of organic matter. The sample is digested with sulfuric and nitric acids to destroy the organic matter, and the ionic mercury is reduced to the elemental state by stannous ion. Then the digestate is aerated with a stream of air to carry the mercury vapor through a heated line into a quartz cell positioned in an atomic absorption spectrophotometer for measurement. Analyses of effluents and aqueous samples gave good recoveries of added mercury. Effluents, wastewaters, water supplies, and aqueous samples secured within manufacturing plants have been analyzed. With minor modification, the procedure has been applied to manufacturing materials such as vinylpyridine, latex, sizing, dyes, caustic, and hydro.     

Occurrence of methylated tin and dimethyl mercury compounds in a mangrove core from Sepetiba Bay,Brazil

Analyses of organotin and organic mercury compounds have been performed in a sediment core from Sepetiba Bay, Brazil, in order to investigate possible methylation pathways in a mangrove environment. The results have revealed that the physico-chemical conditions existing in this type of environment (high organic inputs, anaerobic conditions, microbial activity, etc.) account for high methyltin concentrations (mono-, di- and trimethyltin) in the sediments, which are dependent upon the total load of metal released (e.g. from anthropogenic sources). Furthermore, the presence of dimethylmercury and not monomethylmercury in the samples demonstrated a new pathway of transformation of mercury in the environment: this compound, thought to be unstable in sediment, is assumed to be stabilized by a conjunction of factors, such as high sulphide levels, anoxic conditions and constant inputs of methane into the medium.     

汞的环境生物化学*

汞是人类最早发现和利用的元素之一。汞在环境中以不同化学形态广泛存在,不同的形态具有不同的环境行为和生物效应。从环境中的存在形式,形态分析和对健康的影响等3个方面,对汞元素作了简单介绍。     

Application of chromatographic and electrophoretic methodology to the speciation of organomercury compounds in food analysis

Trace metals such as mercury, especially its organic compounds, are an important risk to the environment and to man due to their accumulation in the food chain. For this reason, the routine determination of the very toxic methylmercury, and of other organic and inorganic mercury compounds in marine and land animals, vegetables, fruits and fresh water is of increasing importance in health and environmental control programmes throughout the world. The majority of speciation methods for organomercurials involve a series of fundamental steps for the identification and quantification of samples of biological origin: extraction or isolation from the matrix; derivatisation and concentration; detection; separation of different species of interest and of interference. Each of these steps, as part of the chromatographic analysis of MeHg and of other organomercurials is revised in this study using food samples.     

Comparison of methods for particulate phase mercury analysis: sampling and analysis

Accurate and reliable sampling and analysis of mercury forms is an overriding aim of any atmospheric monitoring effort which seeks to understand the fate and transport of the metal in the environment. Although a fraction of the total mercury forms found in the atmosphere, particulate phase mercury, Hg(p), is believed to play a prominent role in both wet and dry deposition to the terrestrial and aquatic environments. Currently, microwave acid extraction and thermoreductive methodologies for analysis of Hg(p) samples are widely used. We report on the potential for the use of a thermoreductive method for Hg(p) analysis to evaluate and optimize it for use in routine monitoring networks. Pre-baked quartz filters can be placed in particulate samplers with well-characterized size cuts, such as dichotomous samplers and microoriface impactors. The thermoreductive methodology facilitates rapid analysis after sample collection. It requires no chemical extraction thereby eliminating the potential for contamination and generation of hazardous waste. Our results indicate that, on average, the thermoreductive method yields 30% lower values for fine fraction Hg(p) when compared with microwave acid digestion. This may be due to matrix interferents that reduce the collection efficiency of mercury onto gold preconcentration traps. Results for total particulate mercury samples indicate that on average the thermoreductive method yields 56% lower values for the coarse fraction when compared with microwave acid digestion.Experiments were also conducted in Detroit, MI, USA to investigate whether elevated reactive gaseous mercury (Hg(2+)(g)) in an urban environment can lead to an artifact during the collection of filters for Hg(p) analysis. Our results indicate a significantly higher amount of Hg(p) collected onto a filter using the conventional methodology as compared to a filter collected downstream of KCl-coated annular denuders in the absence of Hg(2+)(g). These results point to the presence of Hg(2+)(g) as an artifact during Hg(p) measurement. These results indicate that a denuder must be utilized upstream of a filter for Hg(p) collection to prevent significant Hg(2+)(g) artifact formation.     

Biotransformation fate and sustainable mitigation of a potentially toxic element of mercury from environmental matrices

The deposition of potentially toxic mercury (Hg) in various ecosystems and subsequent entry into the food chain pose serious concerns to the ecosystem, biodiversity, and public health. In terms of toxicity, Hg is considered as a neurotoxin and capable to augment in food chains and bind to the thiol functional entity in living tissue. Moreover, methylated mercury (CH₃Hg⁺) is a highly toxic form of mercury and extremely difficult to remove from living bodies. Mercury methylation is mainly conducted by microbial and/or chemical processes under appropriate conditions. The mechanisms associated with mercury methylation inside the environment, their sources, production/degradation rate, and transport into the living organisms are not well understood. In addition, efficient and sustainable remediation strategies are essential to employ for mercury removal. Therefore, this review signifies a possible mechanism for mercury methylation and its transportation in the environment, including molecular mechanisms and genes associated with microbial-mediated mercury methylation, and identifies the gaps in existing research. The transport of Hg into the human body and associated health risks are given with suitable examples. Moreover, the escalating anthropogenic activities, the rate-limiting factors, and the sustainable remediation strategies implemented for mercury removal from the environment are discussed. This study will provide a scientific base, direction, and progress in future studies.     

Determination of the different states of mercury in seawater near the Vlora and Durres Bays

Because of the toxicity and mobility of organic mercury, there is a need for determination of organic and inorganic mercury at very low concentrations in the environment, especially in seawater. A procedure for extraction and determination of low concentrations of the different states of mercury - total, inorganic, and organic - in seawater, by cold vapour atomic absorption spectroscopy (CVAAS) is described.Inorganic mercury only was directly reduced to the Hg(0) state by tin(II) chloride under strongly acid conditions (H(2)SO(4)) and mercury metal (Hg(0)) was determined by cold vapour atomic absorption spectroscopy. Organic and inorganic mercury were extracted, with toluene, as the bromide derivatives and re-extracted, together, into ammonium chloride solution. Organic mercury was converted into inorganic mercury by thermal digestion at 80-90 degrees C in the presence of strong oxidants. These two states of mercury were determined together as total mercury. Inorganic mercury was measured directly after pre-concentration of the sample by toluene extraction. Toluene dissolved in aqueous phase after re-extraction of the sample was removed by heating for 30 min at 80-90 degrees C. Organic mercury was calculated as the difference between total and inorganic mercury.The sensitivity of the method is 0.0001 ng mL(-1) Hg, depending on sample volume.     

Periodicity-controlled two-dimensional crystalline colloidal arrays

We developed a convenient and fast approach to preparing close-packed two-dimensional (2-D) particle arrays on mercury surfaces. Addition of cosolvents, such as alcohols, to aqueous colloidal particle suspensions induces spreading and self-assembly of the particles into 2-D arrays on top of the mercury surface. We can fabricate large-area close-packed 2-D arrays (>70 cm(2)) within 30 s. We attached these 2-D arrays to functional hydrogel films such that the 2-D array spacings were altered by the hydrogel volume response to the environment. We directly observed the hydrogel volume induced 2-D array spacing changes by using confocal laser scanning microscopy to monitor the spacings of fluorescent polystyrene particle 2-D arrays in response to changes in pH, solvent composition, temperature, etc.     

Some aspects of speciation and reactivity of mercury in various matrices

Speciation of mercury compounds in environmental and biological samples requires different techniques and different approaches. This speciation is mandatory to explain the toxicity, the reactivity and the bioavailability of mercury. It is dominated by inorganic mercury species Hg(II) and Hg(0), and the organic mercury species CH₃Hg and (CH₃)₂Hg. In this paper, some aspects of mercury speciation are presented in terms of:- mercury reactivity (Hg(II) complexation and reduction),- mercury species distribution in the main compartments of the environment     

Cover Picture: Trimeric Perfluoro‐ortho‐phenylenemercury: A Versatile Lewis Acidic Host (Chem. Eur. J. 21/2003)

The cover picture shows how trimeric perfluoro‐ortho‐phenylene mercury (center), one of the simplest trifunctional Lewis acidic hosts, interacts with organic molecules to afford various adducts. The planarity of this trinuclear complex as well as its overall polarizability compounded with relativistic effects at mercury permits the occurrence of noncovalent interactions and accounts for the tendency of this compound to form cofacial dimers as observed in the structure of the acetone adduct (top left). With a triply coordinated acetone molecule, the structure of this adduct also substantiates the cooperative effects that arise from the proximity and accessibility of the mercury centers. The complexation of arenes, such as benzene (bottom left) and naphthalene (bottom right), also occurs and leads to the formation of binary stacks in which the arene establishes multiple linkages with the mercury centers of the trifunctional Lewis acids. In addition to displaying unusual coordination environment, the arene units present in those stacks exhibit remarkable phosphorescent properties. For more details, see the paper by F. P. Gabbaï, R. E. Taylor, and M. R. Haneline on p. 5188 ff.     

大气中活性气态汞的分析方法和赋存转化

活性气态汞(Reactive gaseous mercury, RGM),在大气环境中通常被认为是气态的氧化汞,主导大气汞沉降过程,对汞的全球循环至关重要。本文详细介绍了RGM的多种采样和分析方法,讨论并比较了当前技术的优势和局限性;对RGM在大气中的生成、赋存、清除等环境过程以及相关的机制进行了梳理,并探究各过程在大气汞循环过程中的贡献。针对当前RGM分析的难点(如赋存浓度低、采集困难)与关键科学问题(如赋存形态与转化),需着力发展实际环境中RGM采集和形态分析的可行方法,进而深入探究其环境行为。大气中RGM的分析方法和环境行为研究是极具挑战性的任务,将是未来大气汞研究的重要内容之一,对于深入理解RGM在大气汞循环过程中的作用具有重要的意义。     

Monitoring and abatement of environmental mercury pollution using human hair as absorbant

Mercury pollution in the industrial environment of Chile has been studied using hair as a monitor. Data from samples representing people living in the non-polluted and also from the polluted areas show that, hair is an effective and convenient indicator of environmental mercury pollution in Chile. A major source of mercury pollution and its transport is contaminated water. Hair is found to concentrate mercury from water to an extent of 80 to 500 fold increase in hair concentration. This absorption occurs in a contact time of 24 h and thus provides a means of treating mercury containing water to reduce the mercury to acceptable levels. The capacity of hair for this purpose is about 0.2% which means that, with a kilogram of hair /valued at less than 25 cents/ nearly 20.000 litres of contaminated water /at 0.1 ppm mercury/ can be treated. This is an inexpensive and convenient alternative to conventional ion-exchange processes which are generally very expensive, particularly for developing countries.     

Electrochemical removal and simultaneous sensing of mercury with inductively coupled plasma-mass spectrometry from drinking water

Mercury is a naturally occurring metallic chemical element in environment. Environmental levels of mercury vary between water resources. The concentration level of mercury in drinking water is 30 ng/L, which is accepted by US Environmental Protection Agency. Therefore, the simultaneous sensing and treatment of water by recently improved technologies are very important. In this work, inductively coupled plasma-mass spectrometry (ICP-MS) and electrochemical techniques were applied together to determine and remove mercury for the first time. ICP-MS was chosen as a sensitive, multielement capable, powerful, and reliable spectrometry type between other heavy metals determination methods, and it is also applied to research drinking water resources. New nanodimensional surfaces were constructed to respond to specific mercury behavior, and simple, cost-efficient, and practical electrochemical techniques were used to remove mercury existing in drinking water samples. After electrodeposition of mercury over the proposed electrode, treated, clean, and mercury-free water samples were obtained.     

燃煤电站布袋除尘器和静电除尘器脱汞性能比较

采用国际上通用的Ontario Hydro方法（OHM）对中国五个燃煤电站布袋除尘器（FF）/静电除尘器（ESP）前、后的烟气进行采样,应用美国EPA标准方法测定了烟气中Hg0、Hg2+和HgP的浓度。应用DMA80测定固体样品（煤、底灰、ESP飞灰）中的汞浓度。由汞平衡得出各个环节中汞所占的份额。由此得到FF和ESP脱除烟气中汞的性能。安装FF的电站1和2的综合脱除效率约为80%和20%,安装ESP的电站3、4和5的综合脱除效率分别为6%、20%和4%左右。这说明FF比ESP有更加优良的脱汞性能,而且FF/ESP脱除烟气中的汞受到很多因素的影响。     

Detoxification of mercury in the environment

In this study, a green chemistry approach was developed as an option for remediation of toxic mercury in the environment. Twenty mercury compounds were treated with an environmentally friendly agent cyclodextrin to produce stable non-toxic mercury in soil and water. The binding efficiency was determined using high performance liquid chromatography with diode-array detection. The stability of the cyclodextrin mercury complexes toward environmental microorganisms in water was estimated under OECD guidelines using gas chromatography–mass spectrometry. The toxicity of the cyclodextrin mercury compounds to terrestrial organisms was investigated by use of internationally recognized toxicity methods using mercuric acetate as a model contaminant. Key process conditions, for example pH, temperature, and amount of detoxifying agent were investigated and found to have significant effects on the toxicity of mercury. It was found that organic and inorganic mercury pollutants could be mineralized in the environment with cyclodextrins. The bound mercury compounds resisted biodegradation and were found to be non-toxic to environmental microorganisms under laboratory conditions.     

Mercury depth profiles in river and marine sediments measured by the diffusive gradients in thin films technique with two different specific resins

The diffusive gradients in thin films technique (DGT) was used to measure depth profiles of mercury in river and marine sediments in situ to a spatial resolution of 0.5 cm. Agarose gel was used as the diffusive gel in the DGT probes. Two different selective resins—Chelex 100 with iminodiacetic groups and Spheron-Thiol with thiol groups incorporated in the polyacrylamide resin gel—were tested. The different capture efficiencies of the two adsorbents enabled the fractions of mercury bound in different species in sediment pore water to be estimated. Mercury concentrations obtained by DGT with Spheron-Thiol resin were very similar to those obtained after centrifugation. This indicates that DGT with Sheron-Thiol resin reports on total dissolved mercury levels. The concentration of mercury measured by DGT with Chelex-100 resin was much lower (by a factor of 5–20) for the same sediment samples. Chelex-100 does not have such a high affinity to mercury as Spheron-Thiol, and so it only reports on the content of labile mercury species, such as inorganic ions and weak complexes. The content of labile mercury species in the river sediment was approximately 20% of the total dissolved mercury in pore water, whereas in marine sediment only 7% of the mercury was present as labile species.     

Speciation of mercury in soils and sediments by thermal evaporation and cold vapor atomic absorption

Evaporation studies of mercury in several chemical compounds, soils, and sediments with a high content of organic matter indicate that a quantitative release is possible at temperatures as low as 400°C. The desorption behaviour from a gold column is not influenced. Only from samples with a thermal prehistory, such as brown coal ash, did mercury evaporate at higher temperatures. Qualitative conclusions can be derived about the content of metallic mercury as well as mercury associated with organic matter or sulfide. A comparison of the analytical results obtained by using the evaporation technique or by dissolving using a mixture of conc. HCl and HNO₃ shows good agreement; the advantages of the evaporation technique are obvious at very low mercury concentrations.     

The effect of humic acid on mercury solubility and complexation

Utilization of mercury in gold mining in the tropics has contributed to large inputs of the metal into the aquatic environment. Although in this activity mercury is utilized in its elemental state, which is relatively immobile and inert, transformations to methylmercury occurring in natural systems lead to mercury contamination of aquatic organisms and the food chain. We investigated the effectiveness and mechanisms involved in the solubilization of mercury in the presence of humic acid, which is an important component of dark river waters in the tropics. Results showed that the solubility of elemental mercury was enhanced due to the presence of humic acid through a solubilization–complexation mechanism, which was attributed to the presence of acid sites on the humic acid molecule, mainly the carboxyl group. Calcium ions in solution prevent humic‐acid‐induced elemental mercury solubility. Although it was demonstrated that the mercury complex formed is more mobile in the presence of humic acid, preliminary results indicated that this mercury complex seem absorbed by fish. Copyright © 2000 John Wiley & Sons, Ltd.     

稻米及其植株器官、环境土壤中总汞的快速测定

为了快速获得稻米及其植株器官、环境土壤等系列相关样品中总汞的含量,运用直接测汞仪测量了稻米及其植株器官、环境土壤等系列相关样品中总汞含量,建立了一种快速检测稻米及其植株器官、环境土壤中总汞的方法.优化了仪器的各项参数,最佳仪器条件为裂解温度为650℃保持40 s,释放温度900℃;验证了液体或固体标准物质作外标曲线对样...