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1.
Acid mine drainage (AMD) from abandoned underground mines significantly impairs water quality in the Jones Branch watershed
in McCreary Co., Kentucky, USA. A 1022-m2 surface-flow wetland was constructed in 1989 to reduce the AMD effects, however, the system failed after six months due to
insufficient utilization of the treatment area, inadequate alkalinity production and metal overloading. In an attempt to improve
treatment efficiencies, a renovation project was designed incorporating two anoxic limestone drains (ALDs) and a series of
anaerobic subsurface drains that promote vertical flow of mine water through a successive alkalinity producing system (SAPS)
of limestone beds overlain by organic compost. Analytical results from the 19-month post-renovation period are very encouraging.
Mean iron concentrations have decreased from 787 to 39 mg l–1, pH increased from 3.38 to 6.46 and acidity has been reduced from 2244 to 199 mg l–1 (CaCO3 equivalent). Mass removal rates averaged 98% for Al, 95% for Fe, 94% for acidity, 55% for sulfate and 49% for Mn during the
study period. The results indicate that increased alkalinity production from limestone dissolution and longer residence time
have contributed to sufficient buffering and metal retention. The combination of ALDs and SAPS technologies used in the renovation
and the sequence in which they were implemented within the wetland system proved to be an adequate and very promising design
for the treatment of this and other sources of high metal load AMD.
Received: 29 June 1998 · Accepted: 15 September 1998 相似文献
2.
The Sanggok mine used to be one of the largest lead-zinc mines in the Hwanggangri mining district, Republic of Korea. The
present study characterizes the heavy metal contamination in the abandoned Sanggok mine creek on the basis of physico-chemical
properties of various kinds of water samples (mine, surface and groundwater). Hydrochemistry of the water samples is characterized
by the relatively significant enrichment of Ca2+, HCO3
–, NO3
– and Cl– in the surface and groundwaters, whereas the mine water is relatively enriched in Ca2+, Mg2+, heavy metals, and HCO3
– and SO4
2–. The more polluted mine water has a lower pH and higher Eh, conductivity and TDS values. The concentrations of some toxic
elements (Al, As, Cd, Cu, Fe, Mn, Pb, Se, Sr, Pb and Zn) are tens to hundreds of times higher in the mine water than in the
unpolluted surface and groundwaters. However, most immobile toxic pollutants from the mine drainage were quickly removed from
the surface water by the precipitation of Al and Fe oxyhydroxides. Geochemical modeling showed that potentially toxic heavy
metals might exist largely in the forms of MSO4
2– and M2+ in the mine water. These metals in the surface and groundwaters could form M2+, CO3
2– and OH– complex ions. Computer simulation indicates that the saturation indices of albite, alunite, anhydrite, chlorite, fluorite,
gypsum, halloysite and strontianite in the water samples are undersaturated and have progressively evolved toward the saturation
condition. However, barite, calcite, chalcedony, dolomite, gibbsite, illite and quartz were in equilibrium, and only clay
minerals were supersaturated. Ground and mine waters seemed to be in equilibrium with kaolinite field, but some surface water
were in equilibrium with gibbsite and seceded from the stability field of quartz. This indicates that surface water samples
in reaction with carbonate rocks would first equilibrate with carbonate minerals, then gibbsite to kaolinite. Investigations
on water quality and environmental improvement of the severely polluted Sanggok creek, as well as remediation methods on the
possible future pollution of the groundwater by the acid mine drainage from the abandoned metal mines, are urgently required.
Received: 4 February 2000 · Accepted: 9 May 2000 相似文献
3.
Xiuzhen Tao Pan Wu Changyuan Tang Hong Liu Jing Sun 《Environmental Earth Sciences》2012,65(3):631-638
Acid mine drainage (AMD) is a common pollution in mining areas due to the oxidation of pyrite and associated sulfide minerals
at mines, tailings and mine dumps. Elevated metals (Fe, Mn, Al) and metalloids (As, Hg) in AMD would deteriorate the local aquatic
environment and influence the water supply. A carbonate basin with deposits of high-arsenic coal in Xingren County, southwestern
China, was chosen to study the behavior of As and other chemical constituents along a river receiving AMD. Heavy metals (Fe,
Mn) and major ions such as (Ca2+, Mg2+, Cl−, SO4
2−) in surface water, and As in sediment and surface water were analyzed. It was found that high concentrations of SO4
2− (1,324–7,560 mg/L) and Fe (369–1,472 mg/L) in surface water were mainly controlled by the interactions between water and
rocks such as the oxidation of pyrite in the local coal seams, precipitation and adsorption of iron minerals. Although ubiquitous
carbonate minerals in the bedrock and the riverbeds, low pH (<3) water was maintained until 2 km downstream from the AMD source
due to the Fe(hydro)oxide minerals coating on the surface of carbonate minerals to restrain the neutralization of acidic water.
Moreover, the formation of Fe(hydro)oxide precipitations absorbed As was dominated the attenuation of As from water to sediment.
Whereas, the dilution also played an important role in decrease of As in river water. 相似文献
4.
The purpose of this work is to characterize the hydrochemical behavior of acid mine drainages (AMD) and superficial waters
from the Adoria mine area (Northern Portugal). Samples of superficial and mine drainage water were collected for one year,
bi-monthly, with pH, temperature, Eh, conductivity and HCO3 determined in situ with chemical analyses of SO4, Ca, K, Mg, Na, Cl, Ag, As, Bi, Co, Cu, Fe, Mn, Ni, Pb, Zn and Cd. In the mine, there are acidic waters, with low pH and
significant concentrations of SO4, and metals (Fe, Mn, Zn, Cu, Pb, Cd and Ni), while in the superficial natural stream waters outside the mine, the pH is close
to neutral, with low conductivity and lower metal concentrations. The stream waters inside the mine influence are intermediate
in composition between AMD and natural stream waters outside the mine influence. Principal Component Analysis (PCA) shows
a clear separation between AMD galleries and AMD tailings, with tailings having a greater level of contamination. 相似文献
5.
Water from the Kombat mine was delivered to the Omatako dam via the 263-km-long Grootfontein-Omatako canal during test runs
in 1997. It is intended to supply water from Kombat and other underground mines in the Otavi Mountain Land to the capital
Windhoek. The Cu-Pb-Zn orebodies are hosted by carbonate rocks and the mine waters are supersaturated with respect to calcite
and CO2. Along the length of the canal, the CO2 partial pressure drops from 10−2.1 atm at the inlet of the Kombat mine to 10−3.5 atm at the end of the canal. This is accompanied by a drop in Ca concentration from about 60 to about 20 mg/l. The heavy
metal concentrations (Cd, Cu, Mn, Pb and Zn) drop along the course of the canal to values far below the national drinking-water
standard. Scavenging by calcium carbonate precipitation is the major depletion mechanism.
Received: 21 June 1999 · Accepted: 29 August 1999 相似文献
6.
The Removal of Dissolved Metals by Hydroxysulphate Precipitates during Oxidation and Neutralization of Acid Mine Waters, Iberian Pyrite Belt 总被引:4,自引:0,他引:4
J. Sánchez España E. López Pamo E. Santofimia Pastor J. Reyes Andrés J. A. Martín Rubí 《Aquatic Geochemistry》2006,12(3):269-298
This study examines the removal of dissolved metals during the oxidation and neutralization of five acid mine drainage (AMD)
waters from La Zarza, Lomero, Esperanza, Corta Atalaya and Poderosa mines (Iberian Pyrite Belt, Huelva, Spain). These waters
were selected to cover the spectrum of pH (2.2–3.5) and chemical composition (e.g., 319–2,103 mg/L Fe; 2.85–33.3 g/L SO4=) of the IPB mine waters. The experiments were conducted in the laboratory to simulate the geochemical evolution previously
recognized in the field. This evolution includes two stages: (1) oxidation of dissolved Fe(II) followed by hydrolysis and
precipitation of Fe(III), and (2) progressive pH increase during mixing with fresh waters. Fe(III) precipitates at pH < 3.5
(stages 1 and 2) in the form of schwertmannite, whereas Al precipitates during stage 2 at pH 5.0 in the form of several hydroxysulphates
of variable composition (hydrobasaluminite, basaluminite, aluminite). During these stages, trace elements are totally or partially
sorbed and/or coprecipitated at different rates depending basically on pH, as well as on the activity of the SO4=
anion (which determines the speciation of metals). The general trend for the metals which are chiefly present as aqueous
free cations (Pb2+, Zn2+, Cu2+, Cd2+, Mn2+, Co2+, Ni2+) is a progressive sorption at increasing pH. On the other hand, As and V (mainly present as anionic species) are completely
scavenged during the oxidation stage at pH < 3.5. In waters with high activities (> 10−1) of the SO 4= ion, some elements like Al, Zn, Cd, Pb and U can also form anionic bisulphate complexes and be significantly sorbed at pH
< 5. The removal rates at pH 7.0 range from around 100% for As, V, Cu and U, and 60–80% for Pb, to less than 20% for Zn, Co,
Ni and Mn. These processes of metal removal represent a significant mechanism of natural attenuation in the IPB. 相似文献
7.
《Applied Geochemistry》2006,21(3):437-445
Oxidation of FeS2 in mine waste releases , Fe(II) and H+, resulting in acid mine drainage (AMD). Subsequent oxidation and precipitation of Fe produces different Fe(III) phases where the mineralogical composition depends on pH and the ambient concentrations of metal ions and complexing ligands. The oxidation and precipitation of Fe in AMD has been studied under various conditions with the intent of understanding the role these processes play in the natural attenuation of metal contaminants in the AMD. The combined process of Fe oxidation and precipitation in AMD from the Kristineberg mine, northern Sweden, has been investigated with pH-stat experiments at pH 5.5 and 7 at 10 and 25 °C. The precipitates formed have been characterised in terms of mineralogy and surface area. Similar phases formed at both temperatures, while the oxidation and precipitation occurred more readily at the higher temperature and higher pH. At pH 7, mainly lepidocrocite (γ-FeOOH) was precipitated while at a lower pH of 5.5, a mixture of schwertmannite, goethite, ferrihydrite and lepidocrocite formed. The ambient Zn(II) concentration was immediately reduced to acceptable levels (according to Swedish EPA) at pH 7 whereas a 2–3 weeks ageing period was necessary to achieve the same effect at pH 5.5. The presence of natural organic matter (NOM) reduced the attenuating effect at pH 5.5 after ageing but increased it slightly at pH 7. Addition of Zn(II) at pH 8 resulted in a mixed Fe(III)–Zn(II) precipitate of unknown composition with some Zn(II) adsorbed at the surface. The Fe(III) precipitates formed are potentially useful for the natural attenuation of metal contaminants in AMD although based on these investigations, the degree of success depends upon pH and NOM concentration. 相似文献
8.
9.
Pan Wu Changyuan Tang Congqiang Liu Lijun Zhu TingQuan Pei Lijuan Feng 《Environmental Geology》2009,57(7):1457-1467
The chemical characteristics, formation and natural attenuation of pollutants in the coal acid mine drainage (AMD) at Xingren
coalfield, Southwest China, are discussed in this paper based on the results of a geochemical investigation as well as geological
and hydrogeological background information. The chemical composition of the AMD is controlled by the dissolution of sulfide
minerals in the coal seam, the initial composition of the groundwater and the water–rock interaction. The AMD is characterized
by high sulfate concentrations, high levels of dissolved metals (Fe, Al, Mn, etc.) and low pH values. Ca2+ and SO4
2− are the dominant cation and anion in the AMD, respectively, while Ca2+ and HCO3
− are present at significant levels in background water and surface water after the drainage leaves the mine site. The pH and
alkalinity increase asymptotically with the distance along the flow path, while concentrations of sulfate, ferrous iron, aluminum
and manganese are typically controlled by the deposition of secondary minerals. Low concentrations of As and other pollutants
in the surface waters of the Xingren coalfield could be due to relatively low quantities being released from coal seams, to
adsorption and coprecipitation on secondary minerals in stream sediments, and to dilution by unpolluted surface recharge.
Although As is not the most serious water quality problem in the Xingren region at present, it is still a potential environmental
problem.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
10.
J.-Y. Yu 《Environmental Geology》1998,36(3-4):271-276
A few simple mass balance equations were developed to simultaneously estimate how much the pollutants from acid mine drainage
(AMD) in stream water are diluted and removed during their migration. The application of the equations requires knowledge
of the variations in the concentrations of the dissolved pollutants and the stoichiometry of the precipitation reaction of
the pollutants when none of the pollutant shows a conservative behavior along the stream path. The calculation should be restricted
to the pollutants showing much higher concentrations in the polluted main stream water than in the combining or diluting water
of the same target area.
The mass balance equations were applied to estimate the dilution factor and precipitation fractions of pollutants in Imgok
Creek such as Fe, SO4 and Al from the AMD of Yeongdong mine. The results show that the estimation, especially for SO4 and Al, significantly depends on the kinds of the precipitates. When FeOHSO4 and AlOHSO4 are assumed to precipitate, the maximum removal fractions of SO4 and Al by precipitation are respectively 34% and 46% of the original input, which is much higher than the values estimated
when SO4 is considered to be perfectly conservative. It indicates that the stoichiometry of precipitation reaction is very important
in the interpretation of the pollutant dilution and migration and assessment of environmental impacts of AMD. The applicability
of the mass balance equations may still need to be verified. However, examining the calculated dilution factor and precipitation
fractions with the equations can provide invaluable information on not only the behavior but also unexpected input of the
pollutants in the stream water polluted by AMD and other point sources.
Received: 12 November 1997 · Accepted: 30 March 1998 相似文献
11.
《Applied Geochemistry》2005,20(4):789-805
Mineralogical, hydrochemical and S isotope data were used to constrain hydrogeochemical processes that produce acid mine drainage from sulfidic waste at the historic Mount Morgan Au–Cu mine, and the factors controlling the concentration of SO4 and environmentally hazardous metals in the nearby Dee River in Queensland, Australia. Some highly contaminated acid waters, with metal contents up to hundreds of orders of magnitude greater than the Australia–New Zealand environmental standards, by-pass the water management system at the site and drain into the adjacent Dee River.Mine drainage precipitates at Mt. Morgan were classified into 4 major groups and were identified as hydrous sulfates and hydroxides of Fe and Al with various contents of other metals. These minerals contain adsorbed or mineralogically bound metals that are released into the water system after rainfall events. Sulfate in open pit water and collection sumps generally has a narrow range of S isotope compositions (δ34S = 1.8–3.7‰) that is comparable to the orebody sulfides and makes S isotopes useful for tracing SO4 back to its source. The higher δ34S values for No. 2 Mill Diesel sump may be attributed to a difference in the source. Dissolved SO4 in the river above the mine influence and 20 km downstream show distinctive heavier isotope compositions (δ34S = 5.4–6.8‰). The Dee River downstream of the mine is enriched in 34S (δ34S = 2.8–5.4‰) compared with mine drainage possibly as a result of bacterial SO4 reduction in the weir pools, and in the water bodies within the river channel. The SO4 and metals attenuate downstream by a combination of dilution with the receiving waters, SO4 reduction, and the precipitation of Fe and Al sulfates and hydroxides. It is suggested here that in subtropical Queensland, with distinct wet and dry seasons, temporary reducing environments in the river play an important role in S isotope systematics. 相似文献
12.
Mineralogical controls on mine drainage of the abandoned Ervedosa tin mine in north-eastern Portugal
《Applied Geochemistry》2006,21(8):1322-1334
The Ervedosa Mine, in north-eastern Portugal, has Sn-bearing quartz veins containing cassiterite and sulphides that cut Silurian schists and a Sn-bearing muscovite granite. These veins were mined for Sn and As2O3 until 1969. Cassiterite, the main Sn ore, has alternate lighter and darker growth-zones. The darker zones are richer in Fe, Nb, Ta and Ti, but poorer in Sn than the adjoining lighter zones. Exsolution blebs of ferrocolumbite, manganocolumbite, Ti ixiolite, rutile, ilmenite and rare wolframite were found in the darker zones. Arsenopyrite is the most abundant sulphide and contains inclusions of pyrrhotite, bismuth, bismuthinite and matildite. Other sulphides are pyrite, sphalerite, chalcopyrite and stannite. Secondary solid phases consisting mainly of hydrate sulphate complexes of Al, Fe, Ca and Mg (aluminocopiapite, copiapite, halotrichite, pickeringite, gypsum and alunogen, meta-alunogen) occur at the surface of the Sn-bearing quartz veins and their wall rocks (granite and schist), while oxides, hydroxides, arsenates and residual mineral phases (albite, muscovite and quartz) occur in mining tailings. Toxic acid mine waters (acid mine drainage AMD), which have high conductivity and significant concentrations of As, SO4 and metal (Cu, Zn, Pb, Fe, Mn, Cd, Ni and Co), occur in an area directly affected by the mine. Surface stream waters outside this area have low conductivity and a pH that is almost neutral. Metal and As concentrations are also lower. Stream waters within the impact area have an intermediate composition, falling between that of the AMD and the natural stream waters outside impact area. Waters associated directly with mineralised veins must not be used for human consumption or agriculture. 相似文献
13.
Thuro Arnold Nils Baumann Sina Brockmann Udo Zimmermann Stephan Weiß 《Geochimica et cosmochimica acta》2011,75(8):2200-3065
The subsurface acid mine drainage (AMD) environment of an abandoned underground uranium mine in Königstein/Saxony/Germany, currently in the process of remediation, is characterized by low pH, high sulfate concentrations and elevated concentrations of heavy metals, in particular uranium. Acid streamers thrive in the mine drainage channels and are heavily coated with iron precipitates. These precipitates are biologically mediated iron precipitates and related to the presence of Fe-oxidizing microorganisms forming copious biofilms in and on the Fe-precipitates. Similar biomineralisations were also observed in stalactite-like dripstones, called snottites, growing on the gallery ceilings.The uranium speciation in these solutions of underground AMD waters flowing in mine galleries as well as dripping from the ceiling and forming stalactite-like dripstones were studied by time resolved laser-induced fluorescence spectroscopy (TRLFS). The fluorescence lifetime of uranium species in both AMD water environments were best described with a mono-exponential decay, indicating the presence of one major species. The detected positions of the emission bands and by comparing it in a fingerprinting procedure with spectra obtained for acid sulfate reference solutions, in particular Fe(III) - SO42− - UO22+ reference solutions, indicated that the uranium speciation in the AMD environment of Königstein is dominated in the pH range of 2.5-3.0 by the highly mobile aquatic uranium sulfate species UO2SO4(aq) and formation of uranium precipitates is rather unlikely as is retardation by sorption processes. The presence of iron in the AMD reduces the fluorescence lifetime of the UO2SO4(aq) species from 4.3 μs, found in iron-free uranium sulfate reference solutions, to 0.7 μs observed in both AMD waters of Königstein and also in the iron containing uranium sulfate reference solutions.Colloids were not observed in both drainage water and dripping snottite water as photon correlation spectroscopy analyses and centrifugation experiments at different centrifugal accelerations between 500g and 46000g revealed. Thus transport and uranium speciation at the investigated AMD sites is neither influenced by U(IV) or U(VI) eigencolloids nor by uranium adsorbed on colloidal particles.This study shows that TRLFS is a suitable spectroscopic technique to identify the uranium speciation in bulk solutions of AMD environments. 相似文献
14.
Bo Peng Xiaoyan Tang Changxun Yu Shurong Xie Meilian Xiao Zhi Song Xianglin Tu 《Environmental Geology》2009,57(2):421-434
The acid mine drainage (AMD) discharged from the Hejiacun uranium mine in central Hunan (China) was sampled and analyzed using
ICP-MS techniques. The analyzing results show that the AMD is characterized by the major ions FeTotal, Mn, Al and Si, and is concentrated with heavy metals and metalloids including Cd, Co, Ni, Zn, U, Cu, Pb, Tl, V, Cr, Se,
As and Sb. During the AMD flowing downstream, the dissolved heavy metals were removed from the AMD waters through adsorption
onto and co-precipitation with metal-oxhydroxides coated on the streambed. Among these metals, Cd, Co, Ni, Zn, U, Cu, Pb and
Tl are negatively correlated to pH values, and positively correlated to major ions Fe, Al, Si, Mn, Mg, Ca and K. The metals/metalloids
V, Cr, Se, As and Sb are conservative in the AMD solution, and negatively-correlated to major ions Na, Ca and Mg. Due to the
above different behaviors of these chemical elements, the pH-negatively related metals (PM) and the conservative metals (CM)
are identified; the PM metals include Cd, Co, Ni, Zn, U, Cu, Pb and Tl, and the CM metals V, Cr, Se, As and Sb. Based on understanding
the geochemistry of PM and CM metals in the AMD waters, a new equation: EXT = (Acidity + PM)/pH + CM × pH, is proposed to
estimate and evaluate extent of heavy-metal pollution (EXT) of AMD. The evaluation results show that the AMD and surface waters
of the mine area have high EXT values, and they could be the potential source of heavy-metal contamination of the surrounding
environment. Therefore, it is suggested that both the AMD and surface waters should be treated before they are drained out
of the mine district, for which the traditional dilution and neutralization methods can be applied to remove the PM metals
from the AMD waters, and new techniques through reducing the pH value of the downstream AMD waters should be developed for
removal of the CM metals. 相似文献
15.
Agustín Gómez-Alvarez Diana Meza-Figueroa Arturo I. Villalba-Atondo Jesús Leobardo Valenzuela-García Jorge Ramírez-Hernández Javier Almendariz-Tapia 《Environmental Geology》2009,57(7):1469-1479
The San Pedro River (SPR) is located in northern Sonora (Mexico) and southeastern Arizona (USA). SPR is a transboundary river
that develops along the Sonora (Mexico) and Arizona (USA) border, and is considered the main source of water for a variety
of users (human settlements, agriculture, livestock, and industry). The SPR originates in the historic Cananea mining area,
which hosts some of the most important copper mineralizations in Mexico. Acid mine drainage derived from mine tailings is
currently reaching a tributary of the SPR near Cananea City, resulting in the contamination of the SPR with heavy metals and
sulfates in water and sediments. This study documents the accumulation and distribution of heavy metals in surface water along
a segment of the SPR from 1993 to 2005. Total concentrations of Cd, Cu, Fe, Mn, Pb, and Zn in surface waters are above maximum
permissible levels in sampling sites near mine tailing deposits. Nevertheless, a significant decrease in the Fe and SO4
2− in surface water (SO4
2−: 7,180–460.39 mg/L; Fe: 1,600–9.51 mg/L) as well as a gradual decrease in the heavy and transition metal content were observed
during the period from 1994 to 2005. Approximately 2.3 km downstream of the mine tailings, the heavy metal content of the
water drops quickly following an increase in pH values due to the discharging of wastewater into the river. The attenuation
of the heavy metal content in surface waters is related to stream sediment precipitation (accompanied by metal coprecipitation
and sorption) and water dilution. Determining the heavy metal concentration led to the conclusion that the Cananea mining
area and the San Pedro River are ecosystems that are impacted by the mining industry and by untreated wastewater discharges
arising from the city of Cananea (Sonora, Mexico). 相似文献
16.
Hun-Bok Jung Seong-Taek Yun Bernhard Mayer Soon-Oh Kim Seong-Sook Park Pyeong-Koo Lee 《Environmental Geology》2005,48(4-5):437-449
Transport and sediment–water partitioning of trace metals (Cr, Co, Fe, Pb, Cu, Ni, Zn, Cd) in acid mine drainage were studied
in two creeks in the Kwangyang Au–Ag mine area, southern part of Korea. Chemical analysis of stream waters and the weak acid
(0.1 N HCl) extraction, strong acid (HF–HNO3–HClO4) extraction, and sequential extraction of stream sediments were performed. Heavy metal pollution of sediments was higher
in Chonam-ri creek than in Sagok-ri creek, because there is a larger source of base metal sulfides in the ores and waste dump
upstream of Chonam-ri creek. The sediment–water distribution coefficients (K
d) for metals in both creeks were dependent on the water pH and decreased in the order Pb ≈ Al > Cu > Mn > Zn > Co > Ni ≈ Cd.
K
d values for Al, Cu and Zn were very sensitive to changes in pH. The results of sequential extraction indicated that among
non-residual fractions, Fe–Mn oxides are most important for retaining trace metals in the sediments. Therefore, the precipitation
of Fe(–Mn) oxides due to pH increase in downstream sites plays an important role in regulating the concentrations of dissolved
trace metals in both creeks. For Al, Co, Cu, Mn, Pb and Zn, the metal concentrations determined by 0.1 N HCl extraction (Korean
Standard Method for Soil Pollution) were almost identical to the cumulative concentrations determined for the first three
weakly-bound fractions (exchangeable + bound to carbonates + bound to Fe–Mn oxides) in the sequential extraction procedure.
This suggests that 0.1 N HCl extraction can be effectively used to assess the environmentally available and/or bioavailable
forms of trace metals in natural stream sediments. 相似文献
17.
Stephanie L. DeSisto Heather E. Jamieson Michael B. Parsons 《Applied Geochemistry》2011,26(12):2004-2018
Hardpans, or cemented layers, form by precipitation and cementation of secondary minerals in mine tailings and may act as both physical and chemical barriers. Precipitation of secondary minerals during weathering of tailings can sequester metal(loid)s, thereby limiting their release to the environment. At Montague Gold Mines in Nova Scotia, tailings are partially cemented by the Fe arsenate mineral scorodite (FeAsO4·2H2O). Previous studies have shown that the formation of scorodite can effectively limit aqueous As concentrations due to its relatively low solubility (<1 mg/L at pH 3–4) and high As content (43–52 wt.% As2O5, this study). Co-existing waters and solids were sampled at Montague Gold Mines to identify present-day field conditions influencing scorodite precipitation and dissolution, and to better understand the mineralogical and chemical relationship between hardpan and tailings. In addition to scorodite, hardpan cements were found to include amorphous Fe arsenate and Fe oxyhydroxide. Nearly all hardpan is associated with historical arsenopyrite-bearing concentrate which provides a source of acidity, As5+ and Fe3+ for secondary mineral precipitation. Pore waters sampled from the hardpan have pH values ranging from 2.43 to 7.06. Waters with the lowest pH values also have the highest As concentrations (up to 35.8 mg/L) and are associated with the most extensive hardpan and greatest amount of weathered sulfide. Samples from areas with discontinuous hardpan and less sulfide have near-neutral pH and lower As concentrations. Detailed petrographic observations indicate that the identity and stability of As-bearing secondary minerals depends on the continued availability of sulfide concentrate. The results of this study are being used to develop remediation strategies for highly weathered, hardpan-bearing tailings that consider the stability of both primary and secondary minerals under various cover scenarios. 相似文献
18.
Iron oxyhydroxide precipitates associated with acid mine drainage (AMD) from the Stearns Coal Zone in southeastern Kentucky
were analyzed for their metal (Al, Cu, Pb, Mn, Ni, and Zn) content. The most concentrated metals within these sediments are
nickel (27–32×103μmol/kg), manganese (16–29×103μmol/kg), and aluminum (13–22×103μmol/kg) as determined by HCl-HNO3 digestion. Metal concentrations associated with the organic fraction as determined by H2O2 digestion were generally far lower, with the exception of aluminum. "Batch" experiments (at initial pH=2.0) were used to
analyze the stability of these metals associated with a contaminated soil. Aluminum was the most mobile of the metals, presumably
the result of the formation of aluminum-sulfate aqueous complexes. The solubilization rates for nickel and iron were very
similar, suggesting that nickel, unlike the other metals, coprecipitated with iron in these sulfatic oxyhydroxides.
Received: 9 October 1997 · Accepted: 15 December 1997 相似文献
19.
Interaction of acid mine drainage with waters and sediments at the Corona stream, Lousal mine (Iberian Pyrite Belt, Southern Portugal) 总被引:1,自引:0,他引:1
E. Ferreira da Silva C. Patinha P. Reis E. Cardoso Fonseca J. X. Matos J. Barrosinho J. M. Santos Oliveira 《Environmental Geology》2006,50(7):1001-1013
This study investigates the geochemical characteristics of the acid mine drainage discharged from the abandoned mine adits and tailing piles in the vicinity of the Lousal mine and evaluates the extent of pollution on water and on the stream sediments of the Corona stream. Atmospheric precipitation interacting with sulphide minerals in exposed tailings produces runoff water with pH values as low as 1.9–2.9 and high concentrations of
(9,249–20,700 mg l−1), Fe (959–4,830 mg l−1) and Al (136–624 mg l−1). The acidic effluents and mixed stream water carry elevated Cu, Pb, Zn, Cd and As concentrations that exceed the water quality standards. However, the severity of contamination generally decreases 4 km downstream of the source due to mixing with fresh waters, which causes the dilution of dissolved toxic metals and neutralization of acidity. Some natural attenuation of the contaminants also occurs due to the general reduced solubility of most trace metals, which may be removed from solution, by either co-precipitation or adsorption to the iron and aluminium precipitates. 相似文献
20.
《Applied Geochemistry》1988,3(3):333-344
The sediments of Lake Anna, Virginia, act as a major sink for incoming acid mine drainage (AMD) pollutants (Fe, SO42−, H+) due to bacterial sulfate reduction (SR). Acid-volatile sulfide (AVS), elemental S, and pyrite concentrations in the sediments of the polluted arm of the lake are significantly greater than those in unpolluted sections of the lake. Measurements of SR using 35SSO42− showed that AVS and S0 are the major short-term (48 h) products of SR in these sediments. Inorganic forms of S(AVS, S0, and FeS2) made up from 60 to 100% of the total sediment S concentration. Pyrite concentrations in the sediment were high but decreased exponentially with distance from the AMD source, suggesting that the pyrite was deposited as stream detritus from the abandoned mines. Iron monosulfide and elemental S concentrations were highest at a station 1 km away from the AMD inflow, indicating formation in situ. There was no evidence for the formation of organic S species. The results suggest that in Fe- and S-rich locations such as those contaminated with acid mine drainage, the distribution of end products of SR may vary substantially from those reported for more moderate environments. 相似文献