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G6 Impacts of mining

Monday, 25 July, 2011

MG6-P1 — 11:00-12:00 and 17:30-18:30
MERCURY DETERMINATION IN SOILS AND FLUVIAL SEDIMENTS IMPACTED BY MINING ACTIVITIES AT THE PARACATU MUNICIPALITY, MINAS GERAIS STATE, BRAZIL
Authors: CESAR, Ricardo1, CASTILHOS, Zuleica2, SIERPE, Ricardo2, SENDEROWITZ, Stephanie3, COLONESE, Juan3, FERREIRA, Marcos 4, BIDONE, Edison4
(1) Federal Fluminense University (UFF), Niterói, RJ, Brazil., geo_ricardocesar@yahoo.com.br; (2) Centre for Mineral Technology (CETEM), Rio de Janeiro, RJ, Brazil; (3) Centre for Mineral Technology (CETEM), RJ, Brazil; (4) Federal Fluminense University (UFF), Niterói, RJ, Brazil;

Paracatu Municipality (northern Minas Gerais State, Brazil) has been suffering with several environmental impacts due to gold mining activities, whose extraction has been performed by mining companies. This investigation proposes mercury determination in soils and fluvial sediments along different micro-basis at the Paracatu Municipality. Samples were collected in October/2010 (17 superficial soils and 17 bottom sediments). The determination of pH was executed in water (1:2.5 – soil:water). Total mercury determination was only performed in the silt-clay fraction (<0.075mm). Mercury contamination intensity in the sediments was evaluated by calculating Geoaccumulation Indexes (IGEO). The IGEO is a logarithmic scale which allows classifying contamination levels according to the geochemical background in the standard shale (40ng/g). In general, soils and sediments were extremely sandy, except for some collecting points of low fluvial energy. Values of pH were in the neutral range (mostly between 5.5 and 7 units), and represents a low contribution in the mercury mobilization. In general, mercury concentrations were about 50ng/g in most of the sampling points. Such values can be considered low, since they are similar to the concentration in the standard shale (40ng/g) and to the São Paulo State pedogeochemical background (50ng/g). Mercury contents in the sediments (mean value = 60.28 ± 111.17ng/g) were higher and presented a lower spatial variance in comparison with sediments (mean value = 52.35 ± 54.05ng/g). Contamination hot spots were found in areas affected by mining activities, suggesting that mercury is good indicator of environmental impacts. In fact, IGEO values indicated the existence of “low to moderately polluted” zones closer to the areas explored by mining companies (especially in the Rico Creek micro-basin). The other IGEO values indicated the occurrence of “practically non-polluted” zones. In the near future, geochemical supports (clay minerals, organic matter and Fe and Al oxi-hydroxides) will be quantified in soils and sediments, in order to understand their role in the mobility and bioavailability of mercury in the environment.

MG6-P3 — 11:00-12:00 and 17:30-18:30
MONITORING RESULTS FOR SULFATE AND METHYLMERCURY IN NORTHERN MINNESOTA STREAMS
Authors: HINES, Neal1, PYLKA, Kevin2
(1)Barr Engineering, nhines@barr.com; (2) PolyMet.

PolyMet Mining and Barr Engineering assessed methylmercury (MeHg) and sulfate in the Embarrass River watershed to address concerns regarding the potential for elevated discharge of MeHg from wetlands and rivers during and after rainfall events. This study included 5 stream sites in addition to Wynne and Sabin Lakes. Findings of this study were: 1) for stream sites with elevated sulfate, MeHg and the fraction of the mercury present as MeHg (“percent that is MeHg”) were not elevated compared to background sites, 2) for the lakes, MeHg concentration did not show a significant trend with depth and, overall, the lakes were net sinks for MeHg (not producing MeHg on a net basis). In addition, from upstream to downstream, MeHg declines both in concentration and in the percent that is MeHg. Findings from this study are consistent with a conceptual model in which MeHg production, presumably from sulfate reducing bacteria, is not stimulated by excess sulfate in this particular ecosystem.

MG6-P4 — 11:00-12:00 and 17:30-18:30
MERCURY POLLUTION IN THE AMBIENT AREA OF GOLD MINING
Authors: XUEJIAO, Liu1, NING, Wang1, GANG, Zhang1
(1) Northeast Normal University, liuxj876@nenu.edu.cn

As the area of the study, Jiapigou goldmine is located in Weisha River drainage area belongs to the upstream of the Songhua River, where the environmental samples, such as water, soil, plants and sediment of Wudaogou, Erdaogou and Shuanghetun in the researched areas have been collected, and the mercury and methylmercury pollution levels of the environmental samples have been determined. Then the results show: the relations of total mercury and methylmercury contamination levels in the environmental factors were plants>soil>sediment>water. Based on the analysis of data, the contents of mercury in plants are directly dependent on the total mercury contents in the atmosphere, when getting into the plants it converse into methylmercury by the biological methylation. The laboratory plants were perennial woody, so it could be proved that the methylmercury in plants also be enriched.

The soil samples collected around the Jiapigou goldmine in October 2009 have been determined and the results show that the largest content of total mercury in soil is away from the goldmine rather than at the gold mining point. And it is in conform to the laws of nature that the contents of the total mercury are higher than those of methylmercury at each collecting point. However, based on the data, there is no specific ratio between the total mercury and the methylmercury. According to the analysis of determinations, the contents of Hg in the soil not only relate with the source intensity, but also relate with the PH value, particles size, composition traits and other factors. After the mercury got into the soil it could be transformed into methylmercury by the biological methylation. The process is complex and affected by soil characteristics, so the rate of the conversion is uncertainty at the present time. Based on the experiments, the index of geo-accumulation has been applied to calculate the level of mercury pollution, and the assessment results show that the mercury pollution level of the 21 selecting points in the researched region are partial moderately polluted. So it can be proved that the researched region is under a certain threat of the mercury pollution.

MG6-P5 — 11:00-12:00 and 17:30-18:30
THE TEMPORAL AND SPATIAL DISTRIBUTION CHARACTERISTICS OF THE GASEOUS MERCURY AND THE INTERRELATED IMPACT FACTORS ANALYSIS IN JIAPIGOU GOLD MINE IN NORTH CHINA
Authors: NING, Wang1, GANG, Zhang1
(1) Northeast Normal University, nwang@nenu.edu.cn

The method of amalgam process has been applied to gold mining for 180 years in Jiapigou gold mine in north China, Which lead to serious mercury pollution problems. During 2008-2010, along to the river flowing through the gold mine monitoring points have been set within 5km. LUMEX RA-915+ mercury analyzer (www.antpedia.com/pcenter/763/) has been used to determine the content of total gaseous mercury(TGM) according to summer and autumn and meteorological elements such as wind direction, wind speed, atmospheric pressure and so on have been determined simultaneously in order to study the laws of the TGM distribution in seasons and analyze the reasons of the temporal and spatial distribution of the TGM. The soil samples corresponding to the air monitoring points have been collected and the contents of total mercury (THg) and methylmercury (MeHg) have been determined. The conclusions have been arrived: (1) the concentration of TGM decreases with the distance increasing to the mercury source, and based on the monitoring data, whether the gold mining work or not impact the concentration of TGM obviously. (2) the temporal distribution characteristic of TGM is summer>autumn, especially near the gold mine and tailing pond which is more than 5 times. It is concluded that high temperature lead to the mercury diffuse rapidly and the soil and water have become the important released source. (3) In summer TGM of all sampling points are positive correlation to the temperature and correlation index change from 0.337~0.867. The TGM of all monitoring points are perfectly negative correlation to the wind speed and the index vary from 0.734~0.993. However, in autumn high winds lead to negative correlation between TGM and wind speed and the index change 0.461~0.994. Regular low temperature in autumn make the correlation between TGM and temperature decrease and sometimes it is negative. (4) In autumn thermal inversion occur frequently and impact the TGM largely, which have become the main impact factor to the change of TGM. (5)The difference of landform and land surface(water,land,vegetation,and city,etc.) can impact the transport and diffusion of mercury pollutant in atmosphere. The content of soil mercury impacts TGM in a way.
Key words: total gaseous mercury (TGM); Jiapigou gold mine; wind speed; wind direction; thermal inversion;

MG6-P6 — 11:00-12:00 and 17:30-18:30
MERCURY EXCHANGE FLUX AT AIR/SOIL INTERFACE IN GOLD MINE AREA OF JIAPIGOU TOWN IN CHINA
Authors: GANG, Zhang1, NING, Wang1
(1) Northeast Normal university, zhangg217@nenu.edu.cn

Jiapigou gold mine is located in upstream Songhua River in the northeast of China, where amalgam process has been applied as the main smelting method for 180s until now that lead to lots of problem of mercury pollution in the area. In the thesis application of dynamic flux chamber with Zeeman RA915+ was used to determine the mercury flux between the soil and air of the three researched points of Jiapigou town and Erdaocha and Erdaogou in April and may in 2009. Furthermore, the total gaseous mercury (TGM) have been determined around the typical gold mine and mineral processing works. In the end the characteristics of the exchange flux between soil and atmosphere and the TGM are analyzed.
The results show: The daytime flux between soil and air in Jiapigou town is (7.26±47.33ng/(m2·h)).But the daytime flux between soil and air in Erdaogou and Erdaocha are exceptional, which is concluded that the released mercury from the ambient working gold mines in the researched area have disturbed the balance of mercury exchange between the soil and air. However, The mean value of TGM in gold mine area in Jiapigou town is (64.91±33.47)ng/m3, rather higher than that of Changbai mountain’s(3.22±1.78)ng/m3 in the northeast of China and the northern hemisphere background concentration(1.5~2.0 ng/m3), which show that the air has been heavily polluted in the area due to the gold mining activities of amalgam process.

* Under the auspices of National Natural Science Foundation of China (No.40673059); Under the auspices of measure and test funds of Northeast Normal University.
Author Introduction: Zhang Gang, male, Doctor, major research: control of the atmosphere pollution; E-mail: zhangg217@nenu.edu.cn
** Communication author: Wang Ning, female, Doctor, Prof.; E-mail: nwang@nenu.edu.cn

MG6-P7 — 11:00-12:00 and 17:30-18:30
MERCURY IN CALIFORNIA’S NEW ALMADEN MINING DISTRICT, NORTH AMERICA’S LARGEST MERCURY PRODUCER AND WORLD’S 5TH-LARGEST
Author: AUSTIN, Carrie1
(1) CalEPA, SF Bay Water Board, caustin@waterboards.ca.gov

In its heyday, New Almaden was widely covered by the popular and scientific press and helped to fuel westward expansion. In contrast, few of the many environmental studies conducted around New Almaden in the last 15 years have been published in journals, although many are posted to websites. The purpose of this poster is to make these studies known and available to mercury researchers. This poster is available at: www.waterboards.ca.gov/sanfranciscobay/water_issues/programs/TMDLs/

In accordance with common mining practices (1846–1975), calcines were disposed near creeks. Winter storm flows (Mediterranean climate) transport wastes downstream. In the 1930’s, two reservoirs were constructed in polluted creeks adjacent to New Almaden, at the top of the watershed. Halfway down this watershed, a lake now fills abandoned gravel quarry pits. In the 1860’s, wetlands at the bottom of the watershed were diked to create salt ponds. Now, the largest tidal wetland restoration project on the west coast is underway to restore these salt ponds back to wetlands, and scientists are studying mercury in them and upstream.

Aqueous total MeHg reached 10, 50, and 140 ng/L reservoirs and lake before solar-powered water circulators were installed to increase oxygen levels. Tot Hg in age-1 Largemouth bass (7–9 cm) was 0.96, 0.83, and 0.39 mg/kg. TotHg in adult Largemouth bass (42–44 cm) was 4.3, 6.1, and 2.3 mg/kg.

MG6-P8 — 11:00-12:00 and 17:30-18:30
MERCURY CONCENTRATION IN SUSPENDED SOLIDS IN MADEIRA RIVER AND IN SOME AFFLUENTS, RONDÔNIA STATE, BRAZILIAN AMAZON.
Authors: NASCIMENTO, Elisabete1, GALVÃO, Roberta2, HOLANDA, Igor2, CARVALHO, Dario2, BASTOS, Wanderley2
(1) Environmental Biology Laboratoy, betalabmerc@yahoo.com.br; (2) Environmental Biogeochemistry Laboratory;

Naturaly the Madeira river carries a great load from suspended solids, in the order of 40million ton/year, becoming it a transport vehicle the dispersion of organics and inorganics pollutants, as example, the mercury. The study of the space standard distribution an element it assists in such a way in the understanding the processes result that, as in the geochemistry processes control. Having in the activity gold mining that ocurred with intensity in Madeira river in 70 and 80 decades, the objective of this work it was analyze the mercury concentration in suspended solids of the some points distributed in the Madeira river and some of its affluents. For the solids suspended collection a surface water sample collected to each three months during the period of April/2009 the December/2010. For solids suspended determination a filtering system was used the vacuum with filter of cellulose 0,45um poro size, and mercury concentration quantification had been carried through by atomic absorption spectrophotometry by cold vapor generation (FIMS-400). Greater values of mercury found in suspends solids had been found in affluents of Madeira river and in rainy period (April, May and June/2009), they are 0,4047mg.Kg-1 Contra river, 0,3457Hg.Kg-1 Jaci-Paraná river, 0,2306mgKg-1 Caripunas river, 0,4299mg.kg-1 Branco river, and in small affluents, 0,6093mg.Kg-1 Belmont, 0,5106mg.Kg-1 Jatuarana I and 0,4236mg.kg-1 Jatuarana II and the lesser values in the points of the Madeira river, 0,0678mg. Kg-1 Madeira I, 0,0856mg.Kg-1 Madeira II, 0,0691mg.Kg-1 Madeira III, and 0,0836mg.Kg-1 in point Madeira V. It was possible observe, that the mercury concentrations in affluents folloied hidrologic cycle of region, with the greater values verified in the rainy period. In the Madeira river, beyond the mercury values in suspended solids to be well below of the values found in the affluents, these values had not been influenced by hidrologic cycle of the region, that is, the mercury had been remained without space and sazonal variability.

MG6-P9 — 11:00-12:00 and 17:30-18:30
CONCENTRATION LEVEL OF MERCURY IN CONTAMINATED SOILS FROM GOLD MINE SITES AND URBAN AREAS IN KOREA
Authors: CHON, Hyo-Taek1, JUNG, Myung Chae 2, SAGER, Manfred 3
(1) Seoul National University, chon@snu.ac.kr; (2) Sejong University; (3) Austrian Agency for Health and Food Safety.

Most of gold mines in Korea, of which deposits are predominantly gold-bearing hydrothermal quartz veins with/without base metal sulfides, have been closed during 1970s -1980s without any environmental treatments. The significant effects of Hg contamination in the vicinity of the abandoned Au mine sites have been ignored without doubtful consciousness. The range of Hg in soils of the reported 284 gold mines was between 0.002 and 24.07 mg/kg Hg. It was found that particularly 11 gold mines (3.8 % of the studied total Au mines) shows high concentration of greater than 1.00 mg/kg Hg in soils. The average content of Hg in soils from the 11 mines is in the range of 1.01 to 2.97 mg/kg, which is abnormally high Hg level in mine site soils compared with the world average upper value of 0.25 mg/kg Hg in normal soils. The concentration level of Hg in soils and dusts collected from Seoul metropolitan city, whose population and registered motor vehicles were more than 10.45 and 2.95 millions in 2008, respectively, was in the range of 0.34-1.76 (med. 0.21) and 0.01-4.41(med. 0.39) mg/kg, respectively. The median value of Hg in soils and dusts is comparable to 0.25 mg/kg, but the maximum and 75 percentile value of Hg in soils and dusts imply the contamination effects in the city.

MG6-P10 — 11:00-12:00 and 17:30-18:30
ASSESSMENT OF HG DISTRIBUTION IN THE ENVIRONMENT AROUND A CU SMELTER (KARABASH, RUSSIA)
Author: TATSY, Yury1
(1)Vernadsky Institute of Geochemistry and Analytical Chemistry, tatsy@geokhi.ru

High levels of uncontrolled releases of mining and metallurgical industry have a disastrous impact on the environment. Karabash is a copper smelting town in the southern Ural Mountains of Russia. For many decades of the use of old technologies of raw material processing, the Karabash copper smelter has released over the city and surrounding area more than 12 million tons of harmful substances and accumulated more than 30 million tons of industrial waste dumps and tailings more. In 1996 the city of Karabash was officially recognized as environmental disaster zone in Russia.

Harmful substances are discharged directly into the water from smelter wast? and tails and to the atmosphere from smelter stacks. In a detailed survey of contaminated areas in previous years a large amount of data on heavy metals (Cu, Pb, Cd, Zn) were obtained. Unfortunately in these works there is only little data on mercury, although it is constantly presents in the raw materials (ores and concentrates) as well as in industrial emissions. The objective of this study was to investigate Hg accumulation in the aquatic and terrestrial environment of Karabash due to the contamination from Cu smelting.

MG6-P11 — 11:00-12:00 and 17:30-18:30
THE STUDY OF MERCURY MASS BALANCE IN LAKE AN-DONG, SOUTH KOREA
Author: HAN, Jin-Seok1
(1)NIER, nierhan@korea.kr

The input, storage and output of total mercury were studied to estimate mass budget for Lake An-dong, located in the South Korea. Lake An-dong, an artificial freshwater lake is located on the upstream of River Nak-dong. Recently, the possibilities of its mercury contamination became an issue since there are the possibilities of historical mercury pollutions due to the locations of abandoned mines and a zinc smelter in the upper stream. Mercury species were measured in atmosphere, tributary and open-lake water column, sediment, planktons and fish samples in the catchments area of Lake An-dong and compared with the national average data to evaluate the mercury pollution status. Deposition and emission of gaseous mercury to and from Lake An-dong were measured along with burial and diffusion rate of total mercury to and from the sediment. The preliminary results of the mass balance study showed that the largest input for total mercury was water inflow from the upper stream during heavy rainy seasons and the sediments are the largest reservoir of mercury with the average of 1.17% of %methylmercury. Only less than 3% of mercury input was arisen from atmosphere deposition. The large missing inputs of mercury in the study were assumed to be storm water input and indirect river inflow to Lake An-dong. The goal of this study was to provide a scientific base of information to guide future mercury reduction strategies by evaluating mercury levels in the examined ecosystem and estimating mercury loading rates.

MG6-P12 — 11:00-12:00 and 17:30-18:30
MONITORING LAND USE CHANGES RELATED TO THE ALMADEN MINE CLOSURE IN CENTRAL SPAIN
Authors: RICO, CELIA1, SCHMID, THOMAS1, SIERRA, MARIA JOSE1, MILLAN, ROCIO1
(1) CIEMAT, celia.rico@ciemat.es

The Almadén district of Spain has an extended history of mercury mining of over two millenniums. After closure of the mining activities in 2002, the region underwent social and economic decline, and alternative activities such as crop cultivation, livestock breeding and tourism are major perspectives to revive the local economy. Therefore, environmental surveying and rehabilitation of areas affected by mining has become a central priority and importance is given to characterize the impact of sites related to past mercury exploitation and processing as well as determining land uses for alternative activities.

The objective of this work is to discriminate and quantify changes in land uses throughout the region as a result of the mine closure. Remote sensing and GIS techniques are applied obtaining digital cartography data from official government sources, acquiring satellite borne data from NASA and implementing a spectral library obtained for different surface covers throughout the area. Furthermore, field observations, ancillary data and corresponding laboratory analyses are included to have site specific information on the different land uses.

The methodology integrates multispectral satellite imagery using Landsat TM (25 March 1989) ETM+ (22 April 2002) and EO-1 ALI (3 April 2008) data. Image pre-processing and processing techniques are applied to standardize the data (atmospheric and geometric correction) and carry out the classification and change detection method. Each scene was classified into several land cover classes relating them to the corresponding human activities during the last and post mining stage. A post classification method has been used, which compares and determines the difference between independently classified images. Validation is thereafter carried out using the information from field, cartography (land use maps from 1980 to 1990 and from 2000 to 2009) and ancillary data (aerial photography and NDVI data).

Results show that within the Almadén municipality for land use such as coniferous woods, irrigated and non-irrigated crop land have increased (33 %, 90% and 20% respectively) and while non-productive land and mining structures have decreased (75%) since mining activities ceased. In this case it is important to associate factors that affect the land cover change such as the fluctuating working population, resources demand and economical inversions.

MG6-P13 — 11:00-12:00 and 17:30-18:30
ENVIRONMENTAL INFLUENCES OF ANCIENT MERCURY SMALL-SCALE ORE ROASTING SITE PŠENK (IDRIJA AREA, SLOVENIA)
Authors: TERŠI?, Tamara1, GOSAR, Mateja1, BIESTER, Harald2
(1)Geological Survey of Slovenia, tamara.tersic@geo-zs.si; (2) Institute of Environmental Geology, Technical University of Braunschweig.

In the initial period of mining activities in Idrija basin (16th and the first half of 17th century), mercury ore processing was performed at various roasting sites in the forests surrounding Idrija, by roasting ore in earthen vessels. The recovery rate of this method was very low; about half of the mercury was lost causing highly elevated mercury concentrations in soils surrounding these sites. Pšenk is one out of 21 localities of ancient roasting sites in the woods surrounding Idrija and one of the largest localities of roasting vessels fragments.

Detailed soil sampling was performed on a 210 x 180 m area to establish the extension of mercury pollution and to investigate mercury species transformation and mobility through the past 400 years. Soil (0–15 cm and 15–30 cm) and humus samples (153) were collected from 73 sampling points and three soil profiles were taken to determine the vertical distribution of Hg in the soils. The main mercury phases were determined using a mercury-thermo-desorption technique. The determined Hg concentrations in soil samples of the investigated area vary from 5.5 to almost 9,000 mg/kg with a median of 200 mg/kg. In humus, Hg concentrations are ranging from 1.4 to 4,200 mg/kg with a median of 20 mg/kg. Extremely high Hg concentrations were found in soil profiles, where Hg concentrations reach up to 37,000 mg/kg. In general, Hg concentrations in all three profiles show a gradual decrease with depth. The results of Hg thermo-desorption analysis in soil samples show the occurrence of cinnabar and Hg bound to soil matrix components; cinnabar and non-cinnabar Hg compounds are almost equally distributed in most of the samples. The high amounts of cinnabar are probably due to the incomplete roasting and large quantities of deposited pottery fragments. Regarding extremely high total Hg concentrations, large amounts of potentially transformable non-cinnabar Hg compounds exist at the area of studied roasting site. In contrast to the immobile cinnabar, matrix bound Hg might be an important source of mobile and transformable Hg compounds, which are potentially bioavailable. The mobility of mercury deposited on soils controls the concentration and toxicity of Hg within soils and nearby water bodies.

Monday, 25 July, 2011