Evaluation on speciation and removal efficiencies of mercury from municipal solid waste incinerators in Taiwan

Two large-scale municipal solid waste incinerators (MWIs) located in Taiwan were selected for conducting flue gas sampling to determine the chemical speciation of mercury by both USEPA Method 29 and Ontario Hydro Method (OHM). In addition, the emission characteristics and removal efficiencies of mercury were evaluated via isokinetic sampling of flue gas upstream and downstream of APCDs. Results indicated that the average removal efficiencies of Hg for MWI-A and MWI-B were 29.56 and 44.70%, respectively. In terms of mercury speciation by USEPA Method 29 and Ontario Hydro Method (OHM), oxidized mercury (Hg2+), in the flue gas was predominant at the inlet of APCD for both incinerators. Less than 30% of mercury in the flue gas existed in the elemental form (Hg0) at APCD inlet. Mercury emitted from the stack also predominated as a form of Hg2+ in MWI-A. Approximately 90% of total mercury emission from the stack existed in the form of Hg2+ for MWI-A. Due to the higher removal efficiency of soluble mercury (Hg2+) in wet scrubber, less total Hg was actually emitted from MWI-B than MWI-A. Regarding the removal efficiency of Hg0 in the flue gas, the APCDs of MWI-A (DSI + FF) had a higher removal efficiency than that of MWI-B (ESP + WS) possibly due to the reduction of Hg2+ which occurred in the wet scrubber.     

Statistical estimate of mercury removal efficiencies for air pollution control devices of municipal solid waste incinerators

Although representative removal efficiencies of gaseous mercury for air pollution control devices (APCDs) are important to prepare more reliable atmospheric emission inventories of mercury, they have been still uncertain because they depend sensitively on many factors like the type of APCDs, gas temperature, and mercury speciation. In this study, representative removal efficiencies of gaseous mercury for several types of APCDs of municipal solid waste incineration (MSWI) were offered using a statistical method. 534 data of mercury removal efficiencies for APCDs used in MSWI were collected. APCDs were categorized as fixed-bed absorber (FA), wet scrubber (WS), electrostatic precipitator (ESP), and fabric filter (FF), and their hybrid systems. Data series of all APCD types had Gaussian log-normality. The average removal efficiency with a 95% confidence interval for each APCD was estimated. The FA, WS, and FF with carbon and/or dry sorbent injection systems had 75% to 82% average removal efficiencies. On the other hand, the ESP with/without dry sorbent injection had lower removal efficiencies of up to 22%. The type of dry sorbent injection in the FF system, dry or semi-dry, did not make more than 1% difference to the removal efficiency. The injection of activated carbon and carbon-containing fly ash in the FF system made less than 3% difference. Estimation errors of removal efficiency were especially high for the ESP. The national average of removal efficiency of APCDs in Japanese MSWI plants was estimated on the basis of incineration capacity. Owing to the replacement of old APCDs for dioxin control, the national average removal efficiency increased from 34.5% in 1991 to 92.5% in 2003. This resulted in an additional reduction of about 0.86 Mg emission in 2003. Further study using the methodology in this study to other important emission sources like coal-fired power plants will contribute to better emission inventories.     

Mercury emissions from a coal-fired power plant in Japan

The emissions study for mercury was conducted at a 700 MW coal-fired plant for the combustion of three types of coal with mercury concentrations of 0.0063, 0.0367 and 0.065 mg/kg. The power plant is equipped with a cold-side electrostatic precipitator and wet type flue gas desulfurization system. During full load operation of the boilers, samples of the input and output streams such as coal, coal ash, ESP ash and post-ESP particulates and flue gas were collected. The Hg concentrations in solid were measured by cold-vapor atomic absorption spectrometry (AAS) after appropriate preparation and acid digestion. Gaseous Hg was collected using a mixed solution of potassium permanganate and sulfuric acid and the Hg concentrations in the samples were measured using cold-vapor AAS. The results were used to examine: (1) overall mass balances; (2) relative distribution in the power plant; (3) equilibrium of Hg species using MALT-2 calculation program; and (4) Hg concentrations in stack emissions. The mass balances estimated in this study were 100, 138 and 89%, respectively, for the coals. Total Hg concentrations in stack gas were 1.113, 0.422 and 0.712 microg(m3N), respectively, for the coals. More than 99.5% of the Hg in the stack emissions were in gaseous form and the proportion in particulate form was extremely low. The relative distribution of Hg in ESP, FGD and Stack ranged from 8.3 to 55.2%, 13.3 to 69.2% and 12.2% to 44.4%, respectively. The results indicated that factors other than the Hg concentration of coals and efficiency of pollution control devices might affect Hg emissions from coal-fired plant. The calculated equilibrium of the distribution of Hg species using the MALT2 program suggest that it is necessary to consider condensation mechanism to interpret the affect of Hg species on the variations of the removal efficiencies of Hg in the ESP.     

Total arsenic, lead, cadmium, copper, and zinc in some salt rivers in the northern Andes of Antofagasta, Chile

Lake Velenje is located in one of the most polluted regions in Slovenia, the Salek Valley. The major source of pollution in the valley is the coal-fired thermal power plant in Sostanj (STPP, capacity 775 MW). It has five separate units. All units have electrostatic precipitators for fly ash removal. Unit 4 also has installed a wet flue gas desulfurisation system (FGD system). Total mercury (THg) concentrations were measured in lignite, slag and ash samples from the STPP. In flue gas, different mercury species (THg, MeHg, Hg2+, Hg0) were determined separately for unit 4 and unit 5 which use different flue gas cleaning technology. Mercury and methyl mercury (MeHg) concentrations were also measured in lake water at different depths, in inflow water, outflow water, rain, snow and lake sediments in order to establish the influence of the power plant on the lake. Most mercury emitted from the power plant is in the elemental form. The ratio between oxidised and elemental Hg depends on the flue gas cleaning technology. Mass balance calculations have been performed for the STPP. The results show that the major sources of mercury in Lake Velenje are wet deposition and lake inflows. Total and MeHg concentrations in the water column are very low and can be compared to other non-contaminated freshwater lakes in the world.     

燃煤电厂烟气中汞形态及含量的采样分析方法

分析燃煤电厂烟气中汞的形态分布,探讨烟气中汞形态及含量的采样分析方法,对各种采样分析方法的特点进行了比较。     

Atmospheric emissions estimation of Hg, As, and Se from coal-fired power plants in China, 2007

Over half of coal in China is burned directly by power plants, becoming an important source of hazardous trace element emissions, such as mercury (Hg), arsenic (As), and selenium (Se), etc. Based on coal consumption by each power plant, emission factors classified by different boiler patterns and air pollution control devices configuration, atmospheric emissions of Hg, As, and Se from coal-fired power plants in China are evaluated. The national total emissions of Hg, As, and Se from coal-fired power plants in 2007 are calculated at 132 t, 550 t, and 787 t, respectively. Furthermore, according to the percentage of coal consumed by units equipped with different types of PM devices and FGD systems, speciation of mercury is estimated as follows: 80.48 t of Hg, 49.98 t of Hg²⁺, and 1.89 t of Hg^P, representing 60.81%, 37.76%, and 1.43% of the totals, respectively. The emissions of Hg, As, and Se in China's eastern and central provinces are much higher than those in the west, except for provinces involved in the program of electricity transmission from west to east China, such as Sichuan, Guizhou, Yunnan, Shaanxi, etc.     

Environmental costs of mercury pollution

Mercury (Hg) has been used for millennia in many applications, primarily in artisanal mining and as an electrode in the chlor-alkali industry. It is anthropogenically emitted as a pollutant from coal fired power plants and naturally emitted, primarily from volcanoes. Its unique chemical characteristics enable global atmospheric transport and it is deposited after various processes, ultimately ending up in one of its final sinks, such as incorporated into deep sediment or bioaccumulated, primarily in the marine environment. All forms of Hg have been established as toxic, and there have been no noted biological benefits from the metal. Throughout time, there have been notable incidents of Hg intoxication documented, and the negative health effects have been documented to those chronically or acutely exposed. Today, exposure to Hg is largely diet or occupationally dependent, however, many are exposed to Hg from their amalgam fillings. This paper puts a tentative monetary value on Hg polluted food sources in the Arctic, where local, significant pollution sources are limited, and relates this to costs for strategies avoiding Hg pollution and to remediation costs of contaminated sites in Sweden and Japan. The case studies are compiled to help policy makers and the public to evaluate whether the benefits to the global environment from banning Hg and limiting its initial emission outweigh the benefits from its continued use or lack of control of Hg emissions. The cases we studied are relevant for point pollution sources globally and their remediation costs ranged between 2,500 and 1.1 million US dollars kg(-1) Hg isolated from the biosphere. Therefore, regulations discontinuing mercury uses combined with extensive flue gas cleaning for all power plants and waste incinerators is cost effective.     

Emissions of mercury and other trace elements from coal-fired power plants in Japan

To evaluate trace element emissions from modern coal-fired power plants into the atmospheric environment in Japan, trace elements in the coal used in electric utility boilers, stack concentrations, emission rates and emission ratios of coal-fired power plants, and proportions of trace elements in coal-fired power plants were studied. The elements were As, B, Be, Cd, Co, Cr, F, Hg, Mn, Ni, Pb, Sb, Se and V, which are designated in the Law of Pollutant Release and Transfer Register. The particulate trace elements were collected in an electrostatic precipitator and a wet desulfurization scrubber. Emissions into the atmosphere were lower than 1% of the quantity in coal, but the volatile trace elements showed somewhat higher emission ratios. For mercury, the mean concentration in coal was 0.045 ppm, the mean emission rate was 4.4 microg/kW h, and the mean emission ratio was 27%, the highest ratio among all elements in this study. The total annual emission of mercury from coal-fired power plants of the electric power industry in Japan was estimated to be 0.63 t/y. On the basis of these data, the atmospheric environment loads from a coal-fired power station were investigated. The calculation of stack gas dispersion showed that maximum annual mean ground level concentrations were in the order of 10(-2) to 10(-5) of the background concentrations, and that the adverse effect of the emissions from the coal-fired power station was small.     

Heavy metal removal from waste water from wet lime(stone)—gypsum flue gas desulfurization plants

Waste water from wet lime(stone) gypsum flue gas desulfurization processes for coal-fired boilers contains suspended solids (gypsum, silica, hydroxides of iron and aluminum) and soluble salts (chlorides and sulfates of calcium, sodium and magnesium). Furthermore, small amounts of heavy metals such as As, Cd, Cr, Cu, Hg, Ni, Pb, Sb, Se and Zn are present in these waste water streams. A treatment method has been developed to remove these heavy metals very efficiently. This method has been based on coprecipitation of metal hydroxides and sulfides. The hydroxide and sulfide precipitates are removed by a coagulation/flocculation technique followed by gravity settling. The coprecipitation can be carried out with sodium hydroxide or with lime. Both cases were investigated in two different pilot plants with synthetically composed waste water and with actual waste water from three different types of wet lime(stone)—gypsum flue gas desulfurization plants (lime—gypsum FGD plants without a prescrubber, one using seawater and another using river water as process water; a limestone—gypsum FGD plant with a prescrubber using river water as process water).     

Total mercury,methylmercury and selenium in mercury polluted areas in the province Guizhou,China

The province of Guizhou in Southwestern China is currently one of the world's most important mercury production areas. Emissions of mercury from the province to the global atmosphere have been estimated to be approximately 12% of the world total anthropogenic emissions. The main objective of this study was to assess the level of contamination with Hg in two geographical areas of Guizhou province. Mercury pollution in the areas concerned originates from mercury mining and ore processing in the area of Wanshan, while in the area of Quingzhen mercury pollution originates from the chemical industry discharging Hg through wastewaters and emissions to the atmosphere due to coal burning for electricity production. The results of this study confirmed high contamination with Hg in soil, sediments and rice in the Hg mining area in Wanshan. High levels of Hg in soil and rice were also found in the vicinity of the chemical plant in Quingzhen. The concentrations of Hg decreased with distance from the main sources of pollution considerably. The general conclusion is that Hg contamination in Wanshan is geographically more widespread, due to deposition and scavenging of Hg from contaminated air and deposition on land. In Quingzhen Hg contamination of soil is very high close to the chemical plant but the levels reach background concentrations at a distance of several km. Even though the major source of Hg in both areas is inorganic Hg, it was observed that active transformation of inorganic Hg to organic Hg species (MeHg) takes place in water, sediments and soils. The concentration of Hg in rice grains can reach up to 569 microg/kg of total Hg of which 145 microg/kg was in MeHg form. The percentage of Hg as MeHg varied from 5 to 83%. The concentrations of selenium can reach up to 16 mg/kg in soil and up to 1 mg/g in rice. A correlation exists between the concentration of Se in soil and rice, indicating that a portion of Se is bioavailable to plants. No correlation between Hg and Se in rice was found. Exposure of the local population to Hg may occur due to inhalation of Hg present in air (in particular in Hg mining area) and consumption of Hg contaminated food (in particular rice and fish) and water. Comparison of intake through these different routes showed that the values of Hg considerably exceed the USA EPA Reference Concentration (RfC) for chronic Hg exposure (RfC is 0.0004 mg/m(3)) close to the emission sources. Intake of Hg through food consumption, particularly rice and fish, is also an important route of Hg exposure in study area. In general, it can be concluded that the population mostly at risk is located in the vicinity of smelting facilities, mining activities and close to the waste disposal sites in the wider area of Wanshan. In order to assess the real level of contamination in the local population, it is recommended that biomonitoring should be performed, including Hg and MeHg measurements in hair, blood and urine samples.     

油气管道的杂散电流腐蚀与防护

阐述了杂散电流对油气管道腐蚀的基本原理、特点,针对杂散电流的特点,提出了防止杂散电流对油气管道腐蚀的措施。     

Assessment of atmospheric mercury emissions in Finland

This paper is part of the study of atmospheric emissions of heavy metals conducted by the Finnish Environment Institute in collaboration with the Technical Research Centre of Finland (VTT) under the umbrella of the Finnish Ministry of the Environment. The scope of our study is limited solely to anthropogenic mercury that is emitted directly to the atmosphere. This article addresses emission factors and trends of atmospheric mercury emissions during the 1990s and is based mainly on the database of the Finnish Environmental Administration. In addition, data based on the measurements taken by the VTT regarding emission factors have been used to estimate emissions of mercury from the incineration of waste. The study indicates that the total emission of mercury has decreased from 1140 kg in 1990 to 620 kg in 1997, while industrial and energy production have been on the increase simultaneously. The 45% emission reduction is due to improved gas cleaning equipment, process changes, automation, the installation of flue gas desulfurization process in coal-fired power plants and strict pollution control laws. In the past, some authors have estimated a higher mercury emission in Finland. In this study, it is also observed that there are no big changes in the quality of raw materials. Estimated emission factors can be of great help to management for estimating mercury emissions and also its risk assessment.     

脱硫粉煤灰作为水泥混合材的可行性研究

粉煤灰是燃煤电厂排放的废弃物,带来环境污染、水质污染及堆积占地等问题。然而,对粉煤灰的有效利用,不仅能改善粉煤灰对环境的污染问题,而且利用粉煤灰生产水泥,又可以带来非常可观的经济效益。本文研究的主要内容就是通过试验研究掌握大连市几家电厂排放的粉煤灰特性,探讨脱硫粉煤灰生产水泥的可行性,粉煤灰及粉煤灰混合材料对水泥物理力学性能的影响,确定配制水泥中粉煤灰混合材料的掺入量。     

空间网格式框架结构在多、高层大开间灵活划分房间石膏节能建筑中的研究与应用综述

将"工业固体废渣资源化"是我国建设生态文明型、资源节约型国家的重要举措.制造磷酸排放的大量磷渣(二水石膏)和火力发电厂排烟的大量脱硫石粉的固体废渣,通过工艺转化为"磷石膏"(半水石膏)及"脱硫石膏",两者与天然石膏具有相同的物理、化学指标.石膏类材料另一特性是浇制后的浆液初凝时间快,加缓凝剂后仅30分钟,是砼初凝时间(8小时)1/16,利用此原理采用砼与石膏浆液分层分段浇制成型,从而形成几种新型砼结构体系.正值我国钢结构住宅建筑发展之际,课题组推出"浇制石膏、装配整体式钢网格式框架结构",应用于大开间多高层节能建筑.这些石膏、砼和石膏、钢结构新体系是以多项国家发明专利作为技术支撑,通过理论分析、科学试验及丁程实践,使"变废为宝"的磷石膏、脱硫石膏等石膏类材料取代传统的粘土砖、水泥标砖形成的砌体,对节约土地资源、循环经济均具有显著的促进作用.本课题是一项较庞大的系统工程.本文仅对课题的新型结构体系各方面内容进行综合性介绍,以期"抛砖引玉",在充实提高的基础上,形成具有我国自主知识产权的建筑结构新体系.     

A three-stage system to remove mercury and dioxins in flue gases

Mercury (Hg) from combustion of fossil fuels and waste is the dominant source of anthropogenic Hg emissions, globally amounting to more than 1500 t Hgyear(-1). These emissions must decrease substantially in order to counteract increasing environmental levels of Hg and reduce future toxic effects. Uppsala Energi AB, nowadays (May, 2002) Vattenfall V?rme Uppsala AB, an energy company in Uppsala, Sweden, has invested in equipments for air and water pollution control of their three waste fired steam boilers. The flue gases are cleaned in three stages in series to meet the strict Swedish regulation. Electrostatic precipitators remove most dust in the first stage, wet scrubbers remove most water-soluble gases, and in the last stage a Filsorption unit removes most remaining impurities in particulate as well as gaseous form. The Filsorption process includes additives injection, sorption, and chemical reaction in a reactor and filtration with a fabric filter. The aim with this article is to evaluate the efficiency of the system to recover Hg in flue gases from boilers in routine operation. Flue gases, ashes, and water were sampled yearly for 21 years and analysed for Hg, dioxin, and other potential contaminants received at waste incineration. The results clearly demonstrate the decreasing use of Hg in society the last two decades as influenced by governmental policy regarding Hg. The results also indicate that the equipment efficiently removed Hg and dioxins from the flue gases to a final concentration of approximately 3.5 microg Hgm(-3) n and 0.01 ng dioxinsm(-3) n, corresponding to more than 97 and 99.9% reduction of Hg and dioxins, respectively, by cleaning in three stages. The electrostatic precipitators and Filsorption stages alone, with the scrubber in bypass, removed 90% of Hg in flue gases. Using the scrubber is motivated to remove acid components and additional Hg, but call for water separated after the condensers to be neutralised and cleaned, so that less than 5 microg l(-1) Hg and 0.02 ngl(-1) dioxins remained, before the water was discharged to a recipient. In conclusion, cleaning flue gases in two or three stages reduced Hg emissions well below Swedish regulations. The strict measures to prevent pollution from waste incineration and simultaneously make use of the energy produced are a good example of a local solution for a global problem.     

Mercury in coal ash and its fate in the Indian subcontinent: A synoptic review

In the Indian subcontinent power generation is mainly dependent upon the thermal power units and coal is burnt as a fuel for the production of heat and electricity. In India, bituminous and sub-bituminous coals are used which contain over 40% of ash. At present, 80-90 million tons of fly ashes are generated from 85 existing coal based thermal power plants. Coal contains trace metals of which mercury is most toxic for humans and aquatic fauna. The problem of mercury in the society is not new, but in recent years the Indian subcontinent has gained the reputation of being "a dumping ground for mercury". This study focuses on mercury in fly ash and its releases to the atmosphere and soils cross the country. The utilisation of coal ash in India is also addressed although it is still in its nascent stage. About 10% of produced fly ashes are used in India whereas in Western countries its use is typically over 70%. Regulations from India's Ministry of Environment and Forestry should increase coal fly ash utilisation, although this would require that cost-effective new technology is put to use. As to the release of Hg from ashes disposed of in the environment, the scarce literature suggests that this is negligible or zero, and less problematic than wet or dry deposition of Hg from flue gases.     

Effect of chlorine content in feeding wastes of incineration on the emission of polychlorinated dibenzo-p-dioxins/dibenzofurans

This study attempts to clarify the effects of chlorine content in waste on the formation mechanisms of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in full scale incinerators by proposing and using the principal component analysis (PCA) to compare the congener profiles of PCDD/Fs in the stack flue gases of 17 emission sources, including incinerators and vehicles. Four incinerators, among these 17 emission sources, were sampled and analyzed in this study, and the data for the other 13 emission sources were selected from previous studies. These 17 emission sources can be classified into four categories, including medical waste incinerators (MWIs, H1-H5), municipal solid waste incinerators (MSWIs, M1-M8), vehicle fuel combustion (unleaded gas-fueled vehicles, UGFV; diesel-fueled vehicles, DFV, n = 2) and polyvinylchloride (PVC) facility vent combustors (PVC1 and PVC2, n = 2). PCA was conducted for these emission sources with the fractions of 17 2,3,7,8-congeners in the stack flue gases as variables to clarify the effect of chlorine content in feeding wastes on the emission of PCDD/Fs. From the results of PCA, we extrapolated that the threshold value of the chlorine content was at 0.8-1.1%, and the formation mechanisms of PCDD/Fs are influenced first by whether the chlorine content in the feeding waste is over or below the threshold value then by other factors, which furnaces or APCDs represent. When the chlorine level in the waste is below the threshold value at 0.8-1.1%, the formation of PCDDs dominates, probably because the chlorine is used to chlorinate the non-substituted phenol to produce chlorophenols, which are important precursors for PCDDs. rather than chlorinate the dibenzofuran. While the chlorine level in the waste exceeds this threshold (0.8-1.1%), the rates of formation of PCDFs increase faster than those of PCDDs, probably because the chlorine content in the waste contributes to the deterioration of combustion conditions, and many products of incomplete combustion (PICs) like PAHs, will grow to a substantial level. When PCDD/Fs are formed from PAHs, the formation rates of PCDFs are higher than those of PCDDs.     

Evaluating mercury transformation mechanisms in a laboratory--scale combustion system

Mercury speciation measurements during injections of 10 microg/m3 Hg0(g) into a 42-MJ/h combustion system containing gaseous O2-Ar- and O2-N2-rich mixtures indicate that 43 and 55% of the Hg (g) spike was transformed rapidly (< 0.1 s) to Hg2+X(g) within a refractory-lined heat exchanger where gas temperatures decrease from approximately 620 to 200 degrees C. O2(g) is the probable Hg0(g) oxidant (i.e. X = O2-). The apparent formation of HgO(g) involves a heterogeneous reaction with adsorbed Hg0 or O2 on refractory surfaces or a Hg0(g)-O2(g) reaction catalyzed by corundum (Al2O3) and/or rutile (TiO2) components of the refractory. The potential catalytic effects of Al2O3 and TiO2 on Hg0(g) oxidation were investigated by injecting Al2O3 and TiO2 powders into approximately 650 degrees C subbituminous coal (Powder River Basin, Montana, USA) combustion flue gas. On-line Hg0(g) and total mercury measurements indicate, however, that Al2O3 and TiO2 injections were ineffective in promoting the formation of additional Hg2+X(g). Apparently, either the chemically complex flue gas hindered the catalytic effects of Al2O3 and TiO2, or these compounds are simply not Hg0(g) oxidation catalysts.     

Mercury emissions from coal-fired power stations: The current state of the art in the Netherlands

About 30% of the electricity produced in the Netherlands is generated by coal, all of which is imported. At the same time, the co-combustion of biomass is becoming increasingly important. For the last 25 years, the fate of the elements/trace elements in general and of mercury in particular has been studied in great detail. It appears that on average 50% of the mercury is removed in the ESP (particulate control) and 50% of the remainder is removed in the flue gas desulphurization (FGD), resulting in a total mercury removal of 75%. If a high dust selective catalytic reduction (SCR for NO(x) reduction) is present, the total removal can be up to 90%. The results indicate that on average the removal of mercury during the co-combustion of biomass is similar to that found for full coal-firing. The conclusion is that a modern coal-fired power station with the above-mentioned flue gas cleaning equipment also removes mercury up to 90%. These cleaning devices are being installed to reduce the emission of particulates, sulphur dioxide and nitrogen oxides. This means that mercury abatement can be increased while meeting the EU regulation for SO(2) and NO(x). The application of Best Available Technique (BAT) for coal-fired installations by 1-1-2008 will lead to a further increase in the construction and operation of FGD and DeNO(x) installations.     

Geographic patterns of elemental deposition in the Aegean region of Turkey indicated by the lichen, Xanthoria parietina (L.) Th. Fr

Lichen samples from different parts of the world have been known to accumulate elements to a greater degree than higher plants, if they are exposed to these elements from the atmosphere or from water and sediments. It has been hypothesized that lichens can be used to monitor air pollution around point and area emission sources. Local variation (variation in substrate, age and morphology of lichen samples) of element concentrations would not be large enough to affect the concentration patterns in large areas. We tested this hypothesis in the Aegean region of Turkey, which is very urbanized and industrialized. No such study has been conducted before in this part of the country. A total of 234 samples of the lichen Xanthoria parietina were collected from a 51,800-km2 area. Samples were washed and analyzed by INAA and ICP-AES for 35 elements. The range of the concentrations for most of the elements on a local scale was an order of magnitude lower than for the element concentrations on a regional scale. The mean local coefficient of variance (CV) was found to be 15, providing that the local variation did not affect the concentration of elements in the sampling region. According to cluster analysis, 8 (As, Hg, Pb, Sb, Fe, Mn, Na and K) elements are indicative of important local pollution locations and their zone of impact in the region. By mapping the concentrations of eight indicative elements in lichen Xanthoria parietina of the Aegean region, it was possible to relate deposition to the existence of known sources of pollution in certain areas. Location of pollution sources such as iron-steel plants, and coal burning in the cities, industrial activity and two important coal-fired power plants generally corresponded with locations of highest element accumulations in the lichens.