Mercury Contaminated Sites

During five decades of wood impregnation by HgCl₂, several tons of mercury had been released into the environment. About 4–5 tons of emitted mercury (Hg) penetrated through thick loess layers down to the gravel aquifer. Today, a plume persisting for at least 700 m downgradient is detectable in the groundwater. Later construction activities resulted in redistribution of soil. The upper soil layer (0–30 cm), toxicologically relevant for human health, became therefore spatially contaminated with to to 1500 mg Hg/kg.

Estimation of Hg emissions to air, soil and water is the first step in the regional management and control of areas where Hg contamination is potentially significant and no clear point source of this metal exists, such as in diversified industrial parks. Sepetiba Bay basin, SE Brazil, is an example of such a situation. Over 400 industries, from oil-fired power plants to steel and non-ferrous metal manufacturing to plastics and chemicals, have been installed in the region since the late 196os. Important point sources of metals such as Cd, Zn and Pb have been identified and controlled during the past decade; no significant point source of Hg, however, has been identified in the area. Notwithstanding, Hg is a ubiquitous byproduct of many industries and is also frequently present in urban and domestic wastes (Barcellos and Lacerda 1994; Marins et al. 1996).

Mercury and mercury compounds are widely used in electrical engineering in the production of different gas-discharge instruments (mercury lamps, mercury valves, indicators), converters, commutators (switches, relay, etc.), photoresistors, chemical current sources (especially, dry galvanic cells), gas-filled thyratrons and triodes, semiconducting materials, etc. Production of luminescent lamps is of special importance, because in this case mercury is a constituent part of consumer goods. It has been suggested that the main source of the highly toxic mercury pollution in Russia is luminescent lamps (Avrukh 1994).

The main regularities of location of mercury-bearing gas and oil deposits are discussed. The mantle source of mercury in these deposits is debated. Correlative relations of mercury with other elements are described. Some evaluation examples of reserves of mercury in gas and oil deposits with high mercury content are given. Examples of regional and local prognosis of mercury-bearing deposits are shown.

Mt. Amiata, located in central Italy, is characterized by the presence of large deposits of cinnabar (mercury sulfide) from which mercury has been extracted since ancient Roman times. The Abbadia San Salvatore mining and smelting plant was the largest in the Amiata district until it was permanently shut down in 1982. About 2 million flasks of mercury (34.5 kg each) were produced in the 80-year period the plant was in use. At present, this zone is the site of abandoned mine structures, and in 1990 some buildings were restored and converted for commercial activities. A mercury flux of too g/h from the mine structures was estimated in July 1995 using the LIDAR remote sensing technique. Using point monitors, a map was made of the distribution of air mercury levels around these structures, showing very high values (1000–15 000 ng/m³) near the old furnaces and cooling towers. The air mercury concentrations inside the restored mine buildings range from 200 to 2200 ng/ m³, with higher values in the winter months due to decreased ventilation.

Due to mining and smelting processes, and due to the naturally increased contents of mercury in soil, the wider surroundings of Idrija are contaminated with mercury. The Idrija ore deposit contains rocks enriched with cinnabar originating from periods up to Middle Triassic. Native mercury can be found primarily in Carboniferous clastic rocks which reach the surface in the western part of the ore deposit. In the 1970s, when the production of mercury reached its peak, the first intensive studies of the ecological cycle of mercury were made. New analytical techniques and improved methods for determining the total mercury and methylmercury contents were introduced in order to study the uptake and distribution of this element in the ground, air, water, plants, animals and man. After 20 years, systematic determinations of total mercury in environmental and biological samples were started again. In our work, total mercury in air, lichens sampled in situ, transplanted lichens, carrots and beans were determined, using gold amalgamation cold vapour atomic absorption spectrometry (CV AAS) after acid decomposition under pressure, or in the case of air measurements, the double amalgamation technique followed by CV AAS. Measured concentrations of total gaseous mercury in air varied from to to 277 ng Hg m ³. The total mercury contents in lichens sampled in situ were in the interval between 3 to 23 μg Hg g ¹ dry sample (d.s.). The total mercury content in carrot ranges from approximately 60 to 760 ng Hg g ¹ d.s. The concentrations of total mercury in beans were in the interval between 2 to 23 ng Hg g ⁻¹ d.s.

Our experience suggested that the urine mercury concentration is not a valid indicator of individual internal doses received during intermittent type of exposure to elemental mercury. We decided to define the current internal dose of mercury through the analysis of total blood mercury. Thirty two miners were observed before and immediately after exposure to elemental mercury. Because the workers made use of respiratory protection, the residual external exposure was assessed with a personal sampler in 15 miners. Blood and urine samples of all examined miners were taken before and immediately after exposure for analysis of total mercury. Total mercury was determined in plasma, erythrocytes and also in the 18-h urine samples of 20 miners. The mercury concentration in all urine postshift samples was corrected to a urinary specific gravity of 1.024 and the postexposure 18-h urine samples of 20 workers was corrected to a urine volume of 1 ml/min. Mercury in the blood, urine and gold trap was determined by cold vapour atomic absorption spectrometry. A very good correlation was found between elemental mercury in inhaled air and the postexposure blood mercury concentration (r = 0.96, P = 0.000). A significant increase (P < 0.001) in blood mercury and urine mercury was established after exposure. The urine and blood mercury concentration after exposure was well correlated (r = 0.68, P < 0.001). No correlation was found between the blood mercury concentration before and after exposure (r = 0.29, P > 0.05). A significant increase (P < 0.01) in erythrocyte mercury and predominantly in plasma mercury was also established during exposure. The correlation between plasma and postshift urine mercury was higher (r = 0.82, P = 0.000) than between erythrocyte and postshift urine mercury (r = 0.70, P = 0.002), if the correction of urine mercury concentration to a urine volume of ml/min was used. Our results confirm that blood mercury concentration is a valid and reliable indicator of current or recent individual exposure to elemental mercury at intermittent type of exposure. At this type and level of exposure, urine mercury in postshift samples, particularly if adjusted to a urine volume of ml/min, reflect not only the accumulation of mercury from earlier exposures but partly also the current group level exposure.

To evaluate the degree of contamination with mercury and its transfer in food webs in the active mercury mining area of Idrija, concentrations in soil profiles, plants and animal tissues were analyzed during the period from 1990 to 1996. Total mercury (T-Hg) and methylmercury concentrations (Me-Hg) were determined in body tissues and fur of roe deer, Capreolus capreolus L. (n = 20), their diet (composite plant samples of a minimum of 40 plant species), soil samples, and in tissues of their predators such as the wolf, Canis lupus L. (n = 2), and lynx, Lynx lynx L. (n = 8). The study was focused on the wider area of the active mercury mine in Idrija, the abandoned mercury mining area in Podljubelj, where mining and smelting ceased in 1900, and five non-polluted locations in Slovenia. Special attention was paid to proper sample collection, preparation and storage. The concentration levels of total and methylmercury in roe deer tissues are correlated with those in their composite vegetal diet, and soil samples from the polluted area. A correlation with the distance from the mercury source was observed (T-Hg: r ² < 0.62; Me-Hg: r ² < 0.73). Herbivore tissues which originate from the active mining area contain up to 350 times higher concentrations of mercury than controls. The tissues of old animals mostly contain high Hg concentrations compared to the corresponding tissues of young animals. However, in the Idrija area the relationship with the age of roe deer was less distinctive due to the influence of the particular spatial exposure gradient. Total mercury concentrations in roe deer organs descend as follows: kidney >> liver > fur > pineal gland >> suprarenal gland > spleen > masseter muscle > lung > pituitary gland > eye sections > sections of the central nervous system (CNS). A large portion of Hg (20 to 85%) in animal tissues from the contaminated area was present as methylmercury (except in the liver and kidney), despite the fact that inorganic Hg and elemental Hg are the primary sources of pollution in the area. The percentage of Me-Hg in composite plant samples and soil profiles was very small (0.14 to 2%). Our data indicate that in the terrestrial environment, roe deer tissues can be successfully used as an indicator of mercury contamination, transfer and accumulation processes. Furthermore, a positive correlation between mercury concentrations in certain roe deer and human tissues from residents of the mining area suggests that roe deer tissues may be successfully used as biomonitors and thus as an early warning of elevated mercury concentration levels in man. However, mercury levels in selected predator species do not follow locally enhanced Hg concentrations in their prey (roe deer) or in vegetation and soils from the polluted area. Since the predators selected occupy larger territories and their prey contains different mercury levels, they are considered less suitable for monitoring of locally enhanced Hg contamination.

Former mercury mines and smelter are situated in Rudnany (east Slovakia).

Approximately a century after peak mining and milling activities at two historic mining camps in the western United States, Hg pollution persists in the Carson River, Nevada, and Jordan Creek, Idaho. Active channel sediments in these streams are still enriched in Hg at levels of 2 to 4 orders of magnitude above regional background.

The results of research on estimation of mercury contamination in the areas impacted by gold mining in Siberia — the oldest gold mining region of Russia — were considered. Investigations were carried out at the sites of gold ore and placer deposits in the Krasnoyarsk Krai, the Republic of Buryatia, the Republic of Yakutia, the Chita Oblast and the refining plant in Novosibirsk. Mercury concentrations in the environmental compartments of the industrial areas and background zones ranged from >0.001 to 4.o mg/kg for rocks and minerals; from >1 to 183 ng/m³ for atmospheric air; from >5 to 250 000 ng/ m³ for industrial air; from 0.013 to 18.9 mg/kg for soils; from >5 to 5000 ng/l for dissolved mercury and from >5 to 27 800 ng/I for particulate mercury of natural and industrial waters; from 0.008 to 54.2 mg/kg for bottom sediments. The influence of severe landscape climatic conditions of Siberia with massive or island spreading of permafrost on the extent of mercury contamination in gold mining areas was considered.

Anthropogenic emission sources of gaseous mercury at the contaminated industrial site BSL Werk Schkopau have been determined by measurements and numerical modelling applying a local dispersion model. The investigations are based on measurements from several field campaigns in the period of time between December 1993 and June 1994. The estimation of the source strengths was performed by inverse modelling using measurements as constraints for the dispersion model. Model experiments confirmed the applicability of the inverse modelling procedure for the source strength estimation at BSL Werk Schkopau. At the factory premises investigated, the source strengths of four source areas, among them three closed chlor-alkali productions, one partly removed acetaldehyde factory and additionaly one still producing chlor-alkali factory have been identified with an approximate total gaseous mercury emission of lower than 2.5 kg/day.

Mercury pollution of the environment caused by humans is in the range of 8000 to 40 000 t/a with 6000 to 10 000 t/a of this originating from the mercury-processing industry, 2000 to 20 000 t/a from ore and mineral processing, and up to 10 000 t/a from combustion of fossil fuels.

An on-line system has been applied to measure mercury (Hg) speciation from a pilot combustion simulator and from an industrial scale Municipal Solid Waste Incineration (MSWI) plant in Göteborg, southwest Sweden. Under simulated waste incineration conditions, 60–80% Hg was found in its oxidized form Hg(II). At the MSWI plant, equipped with a modern flue gas cleaning system, Hg at concentrations about 10–15 μg m⁻³ was emitted to the atmosphere, of which 15–20% was Hg(II).

Mercury is very often removed as an impurity and environment pollutant from processing fluid gas streams by adsorption on a fixed bed. Considering the ecological and technological problems related to the presence of mercury in natural gas, INA-Naftaplin has erected at the gas treatment plant Molve (Croatia) processing units that insure complete mercury removal. This chapter deals with the results of 3 years’ experience in practical field application, showing activated carbon mercury removal from natural gas.

Japan has a long history of mercury contamination, the most tragic example being the organic mercury poisoning of Minamata Bay, and the subsequent outbreak of Minamata disease, which killed so many people. Today in Japan there are many cases of mercury contamination of soils in the vicinity of agricultural and industrial chemical plants etc. In other parts of the world, mercury contamination problems, such as those caused by the smelting of gold in the Amazon basin and other tropical regions, have become a worldwide concern.

To date, there is no satisfactory technique known for simultaneous remediation of materials contaminated with mercury and other metals. In the case of mercury-polluted tailings from Brazilian gold-mining areas, there is the opportunity to extract mercury and traces of gold hydrometallurgically, thus making the remediation process cost-effective. Hydrometallurgical techniques are widely used in ore treatment, whereas soil remediation applications are rare. This chapter outlines two variants of an electroleaching process and gives an overview of its thermodynamic fundamentals. Model calculations are presented as well as results from laboratory experiments.

A description is given of the decontamination of a chlor alkali plant which became contaminated with mercury during more than 30 years of production. The project comprises the clean-up of the contaminated areas, the dismantling and demolition of equipment and buildings, and the disposal of contaminated materials in a specially designed landfill. Extensive high-level health and safety measures have been applied in order to protect workers and the environment.

Multimedia environmental surveys and monitoring studies have shown the major sources of mercury contamination in the Lake Superior watershed to be from former industrial and municipal direct discharges and present airborne sources. Walleye from the St. Louis River, the largest US tributary to Lake Superior, and siscowet trout from the lake continue to show elevated mercury tissue levels, limiting safe human and wildlife consumption. The main routes of mercury bioaccumulation in fish appear to be from airborne deposition and recent contaminated sediment sources and through the benthic and planktonic food chains. No evidence for significant background from geologic sources is indicated in upstream river sediments or from Lake Superior sediment core samples dating from about 2000 to 8000 years. B. P.

The contamination sites for the pollution of Hg and other heavy metals, i.e. Fe, Mn, Cr, Co, Ni, Cu, Zn, Cd, Pb and TI, have been detected in the central part of India in the mineral- and coal-rich areas which lie between 18° and 23° N latitude and 80° and 84° E longitude. The heavy metals are found to be associated with the natural resource materials, i.e. minerals and coal, and are emitted into the environment by both natural and human activities. Thirty one sediments samples derived from 20 different ponds and to different river basins were collected and analyzed by AAS. The pollution level of Hg and ten other heavy metals in water and sediments, distribution of Hg in water and sediments, and their sources are described.

The increase and dispersion in aquatic systems of mercury, which is not very abundant in the global environment, are mainly due to the industrial development and intensification of human activities (halogen chemicals, dental and pharmaceutic industries, agriculture, gold mining, etc.). In the Alsace region (northeastern France), the Ill river and one of its tributaries, the Thur, are the most polluted because of industrial wastewaters from the chlorine and soda industry which uses mercury as a cathode in electrolysis.

The Trans Thane Creek Industrial Area (TTCIA) in New Bombay, developed as a chemical zone by the Maharashtra Industrial Development Corporation (MIDC), houses a large number of major and small-scale industries which manufacture and store a number of petrochemical, pharmaceuticals, fine chemicals and pesticide formulations. The creek ecosystem has been monitored three times for total and methylmercury; once during the pre-and postmonsoon periods of 1994, and once during the premonsoon period of _1995. The concentration of total mercury was determined by CVAAS using SnCl, methodology for liberating vapour phase mercury. Reversed phase high performance liquid chromatography (RP-HPLC) with a UV detector was used for the separation and determination of methylmercury. The efficacy of the methodology was assessed through analysis of standard reference material obtained from IAEA (tuna fish, IAEA-350).