Bestimmung von leicht freisetzbarem Cyanid in Böden und Wässern mit der Mikrodestillation

Easy-liberatable cyanide has to be analysed if soils and waters are contaminated by cyanide. The aim of this study was to determine easy-liberatable cyanide in these environmental samples using a micro-distillation apparatus by means of a modified digestion vessel. Pure aqueous solutions of different cyanide species, five contaminated and uncontaminated soil samples and two water samples were analysed by micro-distillation according to the German standards. Recovery was determined by analysis of spiked samples. When using the modified digestion vessels, the pH of 4 which is demanded by the standard method can be adjusted. The recovery of potassium cyanide and weakly-complexed zinc-cyanide ranged from 93–101% for standards, and from 87–98% for spiked samples. In contrast, the recovery of strong iron-cyanide complexes was below 4% both for pure solutions and spiked samples. The precision of the method expressed as a relative standard deviation was 25% in cases of very low easy-liberatable cyanide contents (< 1 mg CN kg^?1) and below 12% in case of high easy-liberatable cyanide contents (> 1 mg CN kg^?1) for contaminated soils. The determination of easily-liberatable cyanide in soils and waters using micro-distillation combined with the modified digestion sample is an alternative to other distillation methods.     

Experimente zum Verbleib von Cyanid nach Aufnahme in Pflanzen

Free cyanide (prussic acid) can be degraded by many organisms. Experimental data on the kinetics of degradation by plants, however, are rare. We experimentally determined the mass balance of potassium cyanide in the system nutrient solution/plant/air In the presence of living willows (Salix alba) and light, free cyanide is almost completely eliminated from the nutrient solution, also by a willow cell suspension (> 99%) and even by a dried-out stem (> 80%). The loss is smaller when the willow is autoclaved (30%). Without a willow, the CN can be recovered to more than 89%. The loss depends on light and transpiration. Volatilization and the formation of complexed cyanide are of minor relevance for the elimination of free CN. The most plausible loss process is metabolism by plants. The transfer into the roots and stem does not change with the light/dark-rhythm. The transfer factor (mg CN/kg plant fw/mg CN/l solution) after 24 h, and related to the initial concentration in solution, is between 2 and 3 for roots, 0.1 to 0.6 for leaves and 0.2 for stems. In the roots of willows and elderberries which were growing on the former gas worksite in Holte, Denmark, high concentrations of cyanides were found. In leaves and fruits, concentrations are a factor of 10 to 1000-fold lower and up to as high as that found in non-exposed control plants. Due to these results, a cyanide-polluted site in Denmark has been remediated with poplar trees.     

Concentrations of arsenic and heavy metals in vegetation at two abandoned mine tailings in South Korea

Untreated abandoned mines may result in hazards to ecosystems due to dispersion of various toxic elements such as arsenic (As) and lead (Pb). Phytoremediation is an alternative of remediation for large scale mine dumps. Plant species were sampled from two abandoned gold (Au) mines in South Korea. Plant samples were digested following the guidelines of US EPA Method 3050 (US-EPA, 1996) and analyzed by inductively coupled plasma mass spectrometry (ICP-MS). Concentrations and bioaccumulation factors of plants are reported and out-performing species are summarized. Poplar trees (Populus davidiana) growing on the Myoungbong tailings were suggested to be a potential species for revegetation of large scale Au mine tailings. Arsenic accumulations of bracken ferns (Pteridium aquilinum) sampled from the Duckum tailings were far lower than those of the reported hyperaccumulators, but the possible chronic adverse effects on residents through daily diet are of concern.     

Arsenic input into the catchment of the River Caudal (Northwestern Spain) from abandoned Hg mining works: effect on water quality

In Asturias (NW Spain) there are many abandoned mines, of which Hg mines are of particular significance from an environmental point of view, due to the presence of Hg and particularly As, which is found either in the form of specific (orpiment and realgar) or non-specific minerals (As-rich pyrite). The instability of these minerals leads to the presence of As-rich mine drainage and spoils heap leachates that enter surface waters or groundwaters. A study including the three most important Hg mines in the region (La Soterraña, Los Rueldos and El Terronal) has been conducted. Watercourses flowing through these mining areas are tributaries of the River Caudal, one of the most important rivers in the area. High concentrations of As were found in some of these waters, which were monitored over a period of three hydrological years and classified according to a water quality index. Those waters sampled close to the mines are generally of poor-to-bad quality, with low alkalinity and in some cases high metal content, but the quality of these waters improves with distance from the mines. The average mass load of As entering the River Caudal has been evaluated as: 200, 12 and 9,800 kg year^?1 from La Soterraña, Los Rueldos and El Terronal mine sites, respectively. Despite the constant input of about 10 tonnes of As per year, the total As concentration remains below analytical detection thresholds on account of the river’s high water flow. Nevertheless, an important part of this As load is presumably retained in the river sediments, representing a potential risk of pollution of the aquatic ecosystems.     

Nutrient distribution in locations of the Gulf of Trieste (northern Adriatic sea) suspected of pollution

Nutrients (ammonium‐nitrogen, nitrite, nitrate, orthophosphate and dissolved silica) as well as some chemical‐physical parameters (temperature, pH, salinity, dissolved oxygen and total suspended matter) were determined in filtered seawater samples taken at the surface, at middle depth and at the bottom, in 6 open‐sea locations of the Gulf of Trieste (northern Adriatic Sea) close to pipeline exits that discharge wastewaters from treatment plants. The collected data allow a comparison of the quality of these open‐sea waters with coastal waters and constitute a reference for successive monitoring in these locations suspected of pollution. A multivariate statistical analysis by the principal component method shows that the considered ecosystem can be modeled with two factors: the first one is referenced to the marine environment, in particular to the decomposition of the organic debris in deep water; whereas the second factor is referenced to the input of freshwaters in the Gulf, driving nitrates from agricultural lands.     

Removal of copper and cyanide from solution using activated carbon

The removal of copper and cyanide from aqueous solution by activated carbon has been investigated. Using a coal-based activated carbon, initial concentrations of 244 to 2441 mg/litre total cyanide combined with 61 to 610 mg/litre copper were reduced to a minimum of 3.6 mg/litre total cyanide and 0.6 mg/litre copper in the presence of a fixed initial quantity of air.Cyanide removal was, found to be augmented by the presence of copper in solution, and by the supply of additional air.It is suggested that cyanide removal is accomplished by catalytic oxidation on the carbon surfaces, and that additional cyanide is removed in the presence of copper by adsorption of cyano-cuprate complexes onto the activated carbon.     

Charakterisierung von Cyaniden in Böden und industriellen Abfällen mit der Fourier-Transformations-Infrarot-Spektrometrie

Soils on sites of former coking and manufactured gas plants as well as on those of blast furnaces are frequently contaminated with cyanides (CN). For assessing the possible risk arising from these hazardous compounds, it is necessary to analyze a considerable number of samples quickly as well as at low costs. Fourier transform infrared (FTIR) spectroscopy has the advantage of being much easier in handling compared to conventional wet-chemical methods for analyzing cyanides. For testing FTIR spectroscopy in the application mentioned above, pure cyanide compounds as well as contaminated purifier waste, blast furnace sludge, and spiked soils were investigated by the reflexion and the transmission techniques. Applicability of the attenuated total reflexion (ATR) technique was limited, since the absorption bands of the crystal used (diamond) overlapped in the range of the cyanide-specific absorption. Although the environmental samples investigated have unfavorable optical properties, results obtained by the transmission technique (KBr pressed pellets) were much better than those obtained by the reflexion technique. Pure cyanide compounds could be distinguished by their IR spectra because their absorption bands of the cyanide-valence vibration differed in position, shape and intensity. The soil matrix did not interfere with either the intensity or the shape and position of the absorption maxima, as concluded from the IR spectra of spiked soil samples. Applying the transmission technique, cyanides are detected at concentrations larger than 500 mg kg^?1 CN. However, the signal was low when the cyanide concentration was below 1,000 mg kg^?1 CN. The FTIR spectroscopy is capable of detecting cyanide compounds in soils and industrial wastes. Additionally, the method provides information about the cyanide species, which is important in toxicological assessments. FIIR spectroscopy is a suitable method for a first survey and environmental assessment of cyanide contaminated areas.     

Vulnerability associated with “symptoms similar to those of mercury poisoning” in communities from Xingu River,Amazon basin

The Brazilian Amazon is known to be a region with high levels of mercury (Hg) in the environment and studies point to an association between high levels of natural mercury in the mother rock and the vast number of clandestine gold mines. Other studies already report the contamination of fish in this region, as well as high levels of Hg in biological material from environmentally exposed populations. On the other hand, this is one of the least developed regions of the planet and it is necessary to understand the vulnerability factors in these populations that may be intoxicated by this element. The purpose of the present study was to investigate the vulnerability factors in communities from Xingu River—Amazon basin probably exposed to Hg. A cross-selection study in two cities localized in Xingu River was conducted, and the sample contained was 268 individuals. sociodemographic questions, lifestyle, diet habits and health conditions were collated. The majority of the sample was female, between 30 and 59 years old, had less than 3 years of educational level and lived in the local of study more than 240 months. There was regular fish consumption (95.9%), principally carnivorous species (80.5%). The visual problem has a highest prevalence (43.3%) between the health problems and about the symptoms of Hg intoxication, memory loss (42.9%), weakness (35.1%), fatigue (34.3%), mood changes (28.7%) and difficulties in concentration (27.2%) was most reported. The female sex, age over 60, educational level below 3 years of study, did not had flush toilet, smoke and least one chronic non-communicable disease represent higher probability to had symptoms of Hg intoxication. Lack of access to health services, low education level and income evidence the susceptibility of this community to diseases and injuries. The vulnerable groups identified in this study should be a priority in public health and environmental health policies.     

Sodium cyanide-induced modulations in the activities of some oxidative enzymes and metabolites in the fingerlings of Cyprinus carpio (Linnaeus)

Carp fingerlings exposed to a sublethal concentration (0.5?mg?L^?1) of sodium cyanide showed a steady decrement over a 7-day period in respiratory rate, rise in lactate dehydrogenase (LDH), and fall in succinate dehydrogenase (SDH) activities followed by variations in lactic and pyruvate levels. Changes in these enzyme activities might be due to impaired oxidative metabolism and severe cellular damage leading to the release of these enzymes. Decline in the activities of SDH and LDH clearly represents a shift from aerobic to anaerobic metabolism as evidenced by elevated lactate and decline in pyruvate levels. The shift to anaerobic metabolism is also reflected by severe drop in the respiratory rate of the fish. This may be a consequence of the blockage of electron transfer from cytochrome c oxidase to molecular oxygen, thus ceasing cellular respiration and it can lead to cellular hypoxia even in the presence of normal hemoglobin oxygenation. Hence, we indirectly reconfirm the inhibition of oxidative metabolism by sodium cyanide. Alterations in behavioral pattern induced by sublethal sodium cyanide exposure may be due to the combination of cytotoxic hypoxia with lactate acidosis, which depresses the central nervous system (CNS); as the brain is the most sensitive site to anoxia, it results in impaired CNS function.     

Cloud point extraction of trace cyanide from environmental waters for indirect flame atomic absorption spectrometric determination

A method has been developed for indirect determination of cyanide in environmental waters based on cloud point extraction (CPE), preconcentration and determination by flame atomic absorption spectrometry (FAAS). The method was based on reduction of Cu(II) to Cu(I) in the presence of cyanide and complexation of the produced Cu(I)(CN)₂^? with gallocyanin (GC⁺) as an ion-pairing reagent at pH 4.0, followed by its extraction into polyethyleneglycol mono-p-nonylphenylether (Ponpe 7.5). Selectivity was improved with the use of suitable masking agents. Various factors influencing separation and preconcentration of cyanide have been investigated, and conditions were optimized, allowing determination of cyanide in the range of up to 1.2 mg L^?1 with a detection limit of 0.00045 mg L^?1. The method has been applied to the determination of cyanide in environmental waters, the results being in agreement with those obtained by a reference method.     

Mercury contamination in agricultural soils from abandoned metal mines classified by geology and mineralization

This survey aimed to compare mercury concentrations in soils related to geology and mineralization types of mines. A total of 16,386 surface soils (0~15 cm in depth) were taken from agricultural lands near 343 abandoned mines (within 2 km from each mine) and analyzed for Hg by AAS with a hydride-generation device. To meaningfully compare mercury levels in soils with geology and mineralization types, three subclassification criteria were adapted: (1) five mineralization types, (2) four valuable ore mineral types, and (3) four parent rock types. The average concentration of Hg in all soils was 0.204 mg kg(-1) with a range of 0.002-24.07 mg kg(-1). Based on the mineralization types, average Hg concentrations (mg kg(-1)) in the soils decreased in the order of pegmatite (0.250) > hydrothermal vein (0.208) > hydrothermal replacement (0.166) > skarn (0.121) > sedimentary deposits (0.045). In terms of the valuable ore mineral types, the concentrations decreased in the order of Au-Ag-base metal mines ≈ base metal mines > Au-Ag mines > Sn-W-Mo-Fe-Mn mines. For parent rock types, similar concentrations were found in the soils derived from sedimentary rocks and metamorphic rocks followed by heterogeneous rocks with igneous and metamorphic processes. Furthermore, farmland soils contained relatively higher Hg levels than paddy soils. Therefore, it can be concluded that soils in Au, Ag, and base metal mines derived from a hydrothermal vein type of metamorphic rocks and pegmatite deposits contained relatively higher concentrations of mercury in the surface environment.     

Some aspects of mining subsidence and its control in the US coalfields

The problem of surface subsidence is rapidly becoming an important environmental consideration of active as well as abandoned mining operations in the USA. The damages attributed to this phenomenon range from simple land settlement to severe structural damage and have been experienced in both rural and urban areas spreading across thirty states.This paper presents a discussion on mining subsidence and its characteristics above US longwall and room-and-pillar mines. The influence of the geological controls on subsidence is discussed in detail and the effects of subsidence on man and his environment are presented and exemplified. In addition, a historical review of rules and regulations governing subsidence-related problems is given, leading to Public Law 95-87, the Surface Mining Control and Reclamation Act of 1977, and finally, the new regulations being developed under the regulatory reform program are discussed.     

Removal of cyanide in aqueous solution by oxidation with hydrogen peroxide in presence of activated alumina

This work is dedicated to the removal of free cyanide from aqueous solution by oxidation with hydrogen peroxide H₂O₂ catalyzed by neutral activated alumina. Effects of initial molar ratio [H₂O₂]₀/[CN^?]₀, catalyst amount, pH, and temperature on cyanide removal have been examined. The presence of activated alumina has increased the reaction rate showing thus, a catalytic activity. The rate of removal of cyanides increases with rising initial molar ratio [H₂O₂]₀/[CN^?]₀ but decreases at pH 10 to 12. Increasing the alumina amount from 1.0 to 30 g/L has a beneficial effect, and increasing the temperature from 20 °C to 35 °C improves cyanide removal. The kinetics of cyanide removal has been found to be of pseudo-first-order with respect to cyanide and the rate constants have been determined.     

高炉洗气含氰废水除氰方法研究—气化分离与富集

本文用ＣＯ２气体气体化分离含氰废水中的氰，用乙醛等醛类吸收富集挥发出来的氰化氢而使氰以回收利用。气化分离除氰后，水中残余氰的浓度小于０．５ｐｐｍ。对醛类与ＨＣＮ反应的动力学和热力学性质的研究和吸收试验表明，乙醛等低分子醛能快速和完全地吸收气化分离出的ＨＣＮ，并得到α－羟基腈、羟基酸及其盐等系列产品。     

Tetracycline antibiotics in the environment: a review

Tetracycline antibiotics are one of the primarily antibiotics groups used for veterinary purposes, for human therapy and for agricultural purposes. Amongst the different antibiotics used, more attention is paid to tetracycline’s as it exhibits serious environmental problems including ecological risks and human health damages. Due to their extensive usage, most of the actual evidence suggests that tetracycline antibiotics are omnipresent compounds found in different ecological compartments. After medication, more than 70 % of tetracycline antibiotics are excreted and released in active form into the environment via urine and feces from humans and animals. Their highly hydrophilic character and low volatility have resulted in significant persistence in the aquatic environment. Very few studies describe the fate and toxicity of tetracycline antibiotics in the environment. Here, we review several important issues with regard to: (1) the toxicity of these compounds on aquatic and terrestrial organisms; (2) their estrogenic effects; (3) their behavior in different ecological systems and; (4) the by-products generated during water treatment. These antibiotics residues promote the development of antibiotic resistant microorganisms, which can induce adverse effect to human health by increasing the risk of certain infections. Based on recent research results, the occurrence of tetracycline antibiotics in the environment inhibits the growth of some terrestrial and aquatic species. Besides, the residual concentrations of such drugs could affect steroidogenic pathway and consequently may cause endocrine disruption of aquatic species. Most of the wastewater treatment plants are not capable of removing effectively the tetracycline antibiotics. Therefore, there is a need to develop alternative processes to remove them from waters. Advanced oxidation processes have been proposed as alternative methods to ensure higher degradation and mineralization of tetracycline antibiotics are present in waters.     

Natural cyanide degradation and impact on Ili River drainage areas from a Goldmine in Xinjiang autonomous region,China

The Ili River is a very important river to the northwest of China and Kazakhstan. The Axi Goldmine is located in the upstream of a branch of the Ili River. The cyanide from the goldmine effluent is a threat to the downstream areas. According to our study, the natural degradation of cyanide conforms to a negative exponential equation in the tailings impoundment, second wastewater pond and even in the receiving streams if the dilution action from other streams were deducted. In the combined action of dilution and natural decomposing, the cyanide from the goldmine effluent does not pose a hazard to the trunk of the Ili River in the normal producing states. The equations of cyanide degradation in the streams and the hydrology parameters could be used to assess the environmental impact on the downstream areas if accidental discharges of cyanide occurred. The available way of decreasing the cyanide impact on the streams is to increase the rate of recycled water so that the lower the wastewater level in the tailing impoundment and the second wastewater pond, the lower is the amount of leakage of wastewater to the streams.     

城市再生水生产工艺中典型紫外防晒剂的去除

随着紫外防晒剂在个人护理用品中的大量使用,其环境及健康风险效应开始得到人们的关注.采用固相萃取-气相色谱-质谱联用(SPE-GC-MS)技术对天津某再生水厂不同处理单元中4种典型紫外防晒剂4-甲氧基肉桂酸-2-乙基己基酯(ethylhexylmethoxycinnamate,EHMC),羟苯甲酮(benzophenone-3,BP-3),3-(4-甲苯基亚甲基)-d-1-樟脑(4-methylbenzylidene,4-MBC),2-氰基-3,3-二苯基丙酸-(2-乙基)己基酸(octocylene,OC)的分布及去除情况进行了检测.结果表明,污水处理厂二级出水中4种目标化合物的浓度范围在34ng·L-1￣2128ng·L-1之间;4种物质在夏秋季(7月和9月)的浓度普遍高于冬季(2月).污水处理厂二级出水中的这4种紫外防晒剂在经过混凝-絮凝处理、连续膜过滤和臭氧氧化处理后出水中的浓度呈下降趋势,总去除率为28.3%￣43.1%,其中臭氧氧化阶段对目标物的去除率最大(16%￣29%),而连续膜过滤阶段去除率最小(3.6%￣8.5%),混凝-絮凝阶段去除率介于2者之间(8%￣21%).由此可见,紫外防晒剂在再生水处理过程中并未得到完全去除,因此再生水的使用需经周密规划,以免对人体健康和生态环境造成威胁.     

Effect of bioavailable arsenic fractions on the collembolan community in an old abandoned mine waste

Environmental Geochemistry and Health - Mine waste from abandoned mines poses a risk to soil ecosystems due to the dispersion of arsenic (As) in the mine waste to the nearby soil environment....     

Geologic processes influence the effects of mining on aquatic ecosystems

Geologic processes strongly influence water and sediment quality in aquatic ecosystems but rarely are geologic principles incorporated into routine biomonitoring studies. We test if elevated concentrations of metals in water and sediment are restricted to streams downstream of mines or areas that may discharge mine wastes. We surveyed 198 catchments classified as "historically mined" or "unmined," and based on mineral-deposit criteria, to determine whether water and sediment quality were influenced by naturally occurring mineralized rock, by historical mining, or by a combination of both. By accounting for different geologic sources of metals to the environment, we were able to distinguish aquatic ecosystems limited by metals derived from natural processes from those due to mining. Elevated concentrations of metals in water and sediment were not restricted to mined catchments; depauperate aquatic communities were found in unmined catchments. The type and intensity of hydrothermal alteration and the mineral deposit type were important determinants of water and sediment quality as well as the aquatic community in both mined and unmined catchments. This study distinguished the effects of different rock types and geologic sources of metals on ecosystems by incorporating basic geologic processes into reference and baseline site selection, resulting in a refined assessment. Our results indicate that biomonitoring studies should account for natural sources of metals in some geologic environments as contributors to the effect of mines on aquatic ecosystems, recognizing that in mining-impacted drainages there may have been high pre-mining background metal concentrations.     

金谷煤业在矿区生态环境保护和治理上的探索与实践

随着煤矿开发强度不断加大,矿山环境影响也日益加大,亟需保护和治理.文中就矿山环境保护与治理工作进行了简要论述,为同类矿山企业的环境保护和治理提供了一种有效途径.参1.