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Inorganic Chemical Pollutants
Published in William J. Rea, Kalpana D. Patel, Reversibility of Chronic Disease and Hypersensitivity, Volume 4, 2017
William J. Rea, Kalpana D. Patel
The U.S. EPA recommends the reference blood concentration of mercury to be below that considered without adverse effects, which is 5.8 ng/mL.470 However, in unexposed populations taken as controls, blood mercury concentration was reported to be 2.73 ng/mL in New York City adults and 1 ng/mL in China.471,472 For many years, mercury was used in diuretics or as an ingredient of antiseptics.466 However, after mercurials were replaced with more specific treatments, signs of mercury intoxication have become rare.473 However, in the past decade, mercury intoxication and poisoning attained high levels474–476 as a result of environmental pollution. The Minamata Bay episode resulting from industrial plastic disposal, the ingestion of contaminated wheat seeds in Guatemala, Iraq, and Pakistan, and contamination from metallic mercury used in gold mining in Brazil are examples of this problem.476,477 Human toxicological data about MeHg poisoning show that symptoms of toxic effects appear at a concentration of mercury in blood of 0.1 μg/mL and death occurs at concentrations above 3 μg/mL.474 It has also been reported that professional exposure to mercury vapor and the release of mercury from or during the removal of amalgam dental fillings increases the blood and plasma concentration of the metal.478–480 After exposure to mercury vapor, blood concentrations attain 18 nM,480 and after exposure to dental amalgam fillings and their removal, plasma concentration attains 5 nM.479 Another important mechanism of exposure is fish consumption. Mercury attains 5.65 ng/mL among regular fish consumers470,471 and levels of 7–10 ng/mL among exposed workers.
Feasibility study on the use of thiosulfate to remediate mercury-contaminated soil
Published in Environmental Technology, 2019
Chao Han, Hui Wang, Feng Xie, Wei Wang, Ting’an Zhang, David Dreisinger
Mercury contamination has caused great concern worldwide. Soil mercury contamination, in particular, has been found at many active and inactive industrial places, such as mining sites and chemical manufacturing facilities [1–5]. Varied levels of mercury contamination in soil have been found in the vicinity of these industrial facilities when mercury and its compounds were used or produced. Pataranawat et al. reported that a mercury level of 10.5 mg kg−1 was detected in surface soil collected from a small-scale gold-mining area in Phichit, Thailand [6]. The total mercury concentration in soil samples collected from the Tapajós gold-mining site (Brazil) was nearly 13 times higher than the background sites [7]. Mercury emission from the refining of non-ferrous metals is also a major source of mercury contamination. The deposition of atmospheric mercury onto soils surrounding metal smelters is commonly observed. Rieuwerts and Farago reported that the mercury concentration of soil samples collected from the lead smelting town of Pribram (Czech Republic) is in the range of 0.07–2.32 mg kg−1 [8]. Stafilov et al. reported that mercury in soil samples collected at a lead and zinc industrial region in the Republic of Macedonia is in the range of 0.01–12 mg kg−1 [9]. Bernaus et al. reported that the level of mercury contamination of the soil around a chlor-alkali plant in the Netherlands reached as high as 1150 mg kg−1 [10].
Leaching of Mercury from Contaminated Solid Waste: A Mini-Review
Published in Mineral Processing and Extractive Metallurgy Review, 2020
Feng Xie, Kaiwei Dong, Wei Wang, Edouard Asselin
The nonferrous metallurgical industry also represents a major contribution of mercury emission (Wang et al. 2012). A typical example is the acid waste produced in the H2SO4 production process through adsorption of SO2 waste gas emitted from pyro-metallurgical processing of copper and zinc. Concentrations of mercury and other hazardous elements in acid waste are usually very high. Emission of mercury from these metallurgical processes also results in the deposition of atmospheric mercury onto soils surrounding the smelters. Liu et al. (2019) reported that the total mercury amount in smelting wastes is over 700 tons each year. It was reported that soil samples collected near a zinc smelter in Central South China showed an average total mercury concentration of 2.27 mg/kg, significantly higher than background level (0.20 mg/kg) (Feng et al. 2006b; Li et al. 2011). A much higher mercury level of 14.6 mg/kg was reported in soil samples collected from another zinc smelting area in Northern China (Zheng et al. 2011). A wide range of mercury level in soil (0.01–12 mg/kg) in a lead and zinc industrial region in the Republic of Macedonia has been reported (Stafilov et al. 2010). In some artisanal and small-scale gold/silver extraction plants, mercury is used for gold extraction from ore (de Andrade Lima et al. 2008). Usually, after crushing and grinding of the ore, mercury is added to the slurry to produce an amalgam, which is burnt to concentrate the gold into a pellet. As a result, the release of elemental mercury may severely contaminate the environment (Paruchuri et al. 2010). Feng et al. (2006a) found that total mercury concentration ranged from 0.9 to 76 mg/kg in soil samples collected from the Tongguan gold mining area in China. Pataranawat et al. (2007) reported that an elevated mercury concentration (10.5 mg/kg) was found in soil samples collected from a small-scale gold mining area in the Phichit province, Thailand. In soil samples collected from the Tapajós gold mining reserve, Brazil, the total mercury concentration was nearly 13 times higher than background levels (Egler et al. 2006).