Lars D. Hylander

500 years of mercury production: global annual inventory by region until 2000 and associated emissions

Since pre-industrial times, anthropogenic emissions of Hg have at least doubled global atmospheric Hg deposition rates. In order to minimize environmental and human health effects, efforts have been made to reduce Hg emissions from industries and power plants, while less attention has been paid to Hg mining. This paper is a compilation of available data on primary Hg production and associated emissions with regional and annual resolution since colonial times. Globally, approximately one million tons of metallic Hg has been extracted from cinnabar and other ores during the past five centuries, half already before 1925. Roughly half has been used for mining of gold and silver, but the annual Hg production peaked during a short period of recent industrial uses. Comparison with total historic Hg deposition from global anthropogenic emissions (0.1-0.2 Mtons) suggests that only a few percent of all mined Hg have escaped to the atmosphere thus far. While production of primary Hg has changed dramatically over time and among mines, the global production has always been dominant in the region of the mercuriferous belt between the western Mediterranean and central Asia, but appears to be shifting to the east. Roughly half of the registered Hg has been extracted in Europe, where Spanish mines alone have contributed one third of the worlds mined Hg. Approximately one fourth has been mined in the Americas, and most of the remaining registered Hg in Asia. However, the Asian figures may be largely underestimated. Presently, the dominant Hg mines are in Almadén in Spain (236 t of Hg produced in 2000), Khaydarkan in Kyrgyzstan (550 t), Algeria (estimated 240 t) and China (ca. 200 t). Mercury by-production from mining of other metals (e.g. copper, zinc, gold, silver) in 2000 includes 48 t from Peru, 45 t from Finland and at least 15 t from the USA. Since 1970, the recorded production of primary Hg has been reduced by almost an order of magnitude to approximately 2000 t in the year 2000. Mining is thus still of similar magnitude as all current anthropogenic Hg emissions to the atmosphere, and mined Hg may account for more than one third of these emissions. Also before use, mercury is emitted from Hg mines locally during the mining and refining processes and from mining waste. Global direct emissions to the atmosphere amount to 10-30 t per year currently (up to 10 at Almadén alone), and probably exceed 10000 t historically. Termination of Hg mining will reduce associated local emissions to the atmosphere and biosphere. Since several economically viable Hg-free alternatives exist for practically all applications of Hg, the production and use of Hg can be further reduced and all primary production of Hg other than by-production terminated.

Mercury net methylation in five tropical flood plain regions of Brazil: high in the root zone of floating macrophyte mats but low in surface sediments and flooded soils.

Mercury net methylation in five tropical flood plain regions of Brazil: high in the root zone of floating macrophyte mats, but low in surface sediments and flooded soils

The Rise and Fall of Mercury: Converting a Resource to Refuse After 500 Years of Mining and Pollution

The link of mercury (Hg) pollution to Hg mining is rarely made, although Hg primary production presently is as large as global Hg emissions from coal combustion. Here we present historical comparisons on global, continental and national scales, covering up to five centuries of Hg production and consumption. Nearly half of the historical consumption has been pre-industrial, notably for silver and gold mining by amalgamation. More than half has been mined in Europe and one quarter in the Americas. Four economic periods with different control of global Hg price and production were discerned: The Hg price rose sharply after 1830 when Spain no longer controlled the Hg market and when consumption started to shift to gold mining in North America and later on industrial uses. In the 1970s, however, the price as well as quantities consumed plunged as a result of rising health and environmental concerns. In Sweden, per-capita consumption has recently dropped below pre-industrial levels, exemplifying a successful implementation of environmental policy. The chlor-alkali industry is still the globally dominating Hg consumer, and large stocks to be decommissioned in industrialized countries need political guidance to avoid transfer of Hg and related risks to other countries, a potential transfer to small-scale miners favoured by low Hg prices.

Fish mercury concentration in the Alto Pantanal, Brazil: influence of season and water parameters

The tropical flood plain Pantanal is one of the worlds largest wetlands and a wildlife sanctuary. Mercury (Hg) emissions from some upstream gold mining areas and recent findings of high natural Hg levels in tropical oxisols motivated studies on the Hg cycle in the Pantanal. A survey was made on total Hg in the most consumed piscivorous fish species from rivers and floodplain lakes in the north (Cáceres and Barão de Melgaço) and in the south part of Alto Pantanal (around the confluence of the Cuiabá and Paraguai rivers). Samples were collected in both the rainy and dry seasons (March and August 1998) and included piranha (Serrasalmus spp.), and catfish (Pseudoplatystoma coruscans, pintado, and Pseudoplatystoma fasciatum, cachara or surubim). There was only a small spatial variation in Hg concentration of the 185 analyzed fish samples from the 200 x 200 km large investigation area, and 90% contained total Hg concentration below the safety limit for regular fish consumption (500 ng g(-1)). Concentration above this limit was found in both Pseudoplatystoma and Serrasalmus samples from the Baia Siá Mariana, the only acid soft-water lake included in this study, during both the rainy and dry seasons. Concentration above this limit was also found in fish outside Baia Siá Mariana during the dry season, especially in Rio Cuiabá in the region of Barão de Melgaço. The seasonal effect may be connected with decreasing water volumes and changing habitat during the dry season. The results indicate that fertile women should restrict their consumption of piscivorous fishes from the Rio Cuiabá basin during the dry season. Measures should be implanted to avoid a further deterioration of fish Hg levels.

Global Mercury Pollution and its Expected Decrease after a Mercury Trade Ban

The high toxicity of methyl mercury (MeHg) is well known, as is the existence of transformations between metallic Hg and MeHg. As a consequence the industrialised countries have adopted Hg-free products and processes, because a continued use of Hg would result in diffuse emissions even if used Hg isrecycled. However, Western Europe exports about 100 tons of Hg to Brazil each year, where it is emitted over the Amazon. The export from Europe began during the 1980s, when a gold mining boom spread like wildfire in the Amazon. Mercury agglutinates gold grains by forming an amalgam. Later on the gold is purified from the Hg by heating. The Hg evaporatesinto the air and is subsequently deposited onto land and in surface waters. Another important Hg polluter is China, whichhas increased its burning of coal without appropriate smoke cleaning devices and is also importing considerable amounts of Hg for industrial use and for use in gold mining. RegionalHg emissions contribute to global Hg pollution due to the mobility of Hg. A ban on the Hg trade in Europe and North America would significantly diminish global Hg pollution. A ban would also result in the closing of the state-owned Hg mine (MAYASA) in Almadén, Spain, the worlds most important anthropogenic Hg source.

Relationship of mercury with aluminum, iron and manganese oxy-hydroxides in sediments from the Alto Pantanal, Brazil

Sediments from nine floodplain lakes in Pantanal were analyzed for a large-scale (300 km) survey of mercury (Hg) load in sediments and soils of the Alto Pantanal and to study the relationship between Hg and reactive aluminum, iron, and manganese oxy-hydroxides. The results were compared with the Hg content in river and stream sediments from the Poconé gold mining area, where Hg has been extensively used and still is in use. The results indicate that the Hg concentrations were elevated in river sediment close to the mining area in Bento Gomes river basin (average in the < 74-microm fraction 88.9 ng Hg g(-1) dry wt.; interquartile range 50.3-119.5), but there was no clear indication that the local Hg emissions have contaminated the remote floodplain lakes, where concentrations were surprisingly low (average in the < 74-microm fraction 33.2 ng Hg g(-1) dry wt. sediment; interquartile range 18.4-46.8), in particular when considering geochemical characteristics of the sediment. The sediment from the floodplain lakes contained less Hg-tot and more reactive iron oxy-hydroxides than soils from the Tapajós area in the Amazon basin. This resulted in a mass ratio between Hg and amorphous oxy-hydroxides of only 5 x 10(-6) for Hg-tot/Fe-oxa (interquartile range 3-7 x 10(-6).

Plant availability of phosphorus sorbed to potential wastewater treatment materials

Abstract. Ecologically engineered wastewater treatment facilities, such as constructed wetlands and infiltration plants, can be further improved in their P retention by using reactive media with a high P-retention capacity. In a sustainable system, the sorbed P should be recycled in agricultural production. The objective of the present study was to determine the plant availability of P sorbed to different P-retention media. The studied media were: crystalline and amorphous blast furnace slag, natural and burned opoka (a bedrock from Poland), limestone, burned lime, soil from a spodic B horizon, and light expanded clay aggregates (LECA). They were soaked in a P solution, rinsed and dried before incorporation into soil. An additional aim was to compare P taken up by barley with amounts chemically extracted for the estimation of plant-available soil P. P sorbed to the crystalline slag was delivered to the barley plants more efficiently than P added in K2HPO4 fertiliser. Soil extraction with acid ammonium lactate correlated well with P taken up by barley and indicated that P bound to Ca is more available to plants than P bound to Al and Fe. The Mg content of the used slag may replace Mg fertilisation in certain soils. It was concluded that among the investigated filter materials, crystalline slag was the most suitable sorbent from an agricultural point of view, since it possessed a large P-sorption capacity and the sorbed P was largely plant available. The heavy metal content of sorption materials must be examined carefully before their application to agricultural soils.

Recent advances in evaluation of health effects on mercury with special reference to methylmercury—A minireview

Mercury is a metal that has long been used because of its many advantages from the physical and chemical points of view. However, mercury is very toxic to many life forms, including humans, and mercury poisoning has repeatedly been reported. The main chemical forms of mercury are elemental mercury (Hg0), divalent mercury (Hg2+) and methylmercury (CH3−Hg+), the toxicities and metabolisms of which differ from each other. Methylmercury is converted from divalent mercury and is a well-known neurotoxicant, having been identified as the cause of Minamata disease. It bioaccumulates in the environment and is biomagnified in the food web. Human exposure to methylmercury is mainly through fish and seafood consumption. Methylmercury easily penetrates the blood-brain barrier and causes damage to the central nervous system, particularly in fetuses. In this paper, we summarize the global mercury cycle and mercury metabolism, toxicity and exposure evaluation, and the thresholds for the onset of symptoms after exposure to different chemical forms of mercury, particularly methylmercury.

Metal removal by bed filter materials used in domestic wastewater treatment

Bed filters using reactive materials are an emerging technology for on-site wastewater treatment. Used materials, which are enriched with phosphorus, can be used as a fertiliser or soil amendment. However the materials can also be enriched with metals from the wastewater. Six materials (opoka, sand, Polonite, limestone, two types of blast furnace slag) exposed to long-term wastewater loading in columns and in a compact filter well filled with Polonite were investigated for metal removal and accumulation. Wastewater applied to the columns had low heavy metal concentrations in the order Zn>Cu>Mn>Ni>Cr. All columns were able to remove 53%-83% of Zn except those filled with sand. Polonite demonstrated a high removal capacity of Mn (>98%), while only the slag materials were able to remove Ni. All materials showed increased Cu, Cr(III), Mn, Pb and Zn content after filtration. Speciation calculations showed that high concentrations of dissolved organic matter might have prevented efficient metal removal, particularly in the case of Cu. The low content of toxic heavy metals in the studied filter materials studied would probably not restrict their use as a fertiliser or soil amendment.

Exploitation of K near roots of cotton, maize, upland rice, and soybean grown in an Ultisol

Native soil potassium (K) has received increased attention as a K source for plants to reduce fertiliser input. Our objective was to compare the ability of different crops to utilise native K. We also wanted to study the exploitation and transport pattern of soil K influenced by plant uptake. Cotton, maize, soybean, and upland rice were cultivated in rhizoboxes. The system permitted sampling of 1-mm-thin soil layers at increasing distances from the plant roots. Both exchangeable and nonexchangeable K was determined and compared with plant uptake of K. The upland rice was superior in K uptake, and took up some nonexchangeable K. Soybean and cotton grew poorly, and K was accumulated in the root zone due to excess supply by mass flow. The importance of mass flow over diffusion of K was verified by calculations and is contrary to accepted principles of K transport in soil. The reasons were high transpiration and restricted root growth. This indicates that mass flow of K in some situations is more important than generally assumed. Mass flow also caused the accumulation of Ca and Na in the root zone, especially that of rice. Accumulation of K in the root zone of rice did not cause K fixation, possibly due to an unknown K-releasing mechanism of upland rice.