Phytoremediation potential of native plants grown in the vicinity of Ahangaran lead–zinc mine (Hamedan,Iran)

This study aims to assess the extent of metal accumulation by plants found in a mining area in Hamedan Province in the central west part of Iran. It also investigates to find suitable plants for phytoextraction and phytostabilization as two phytoremediation strategies. Plants with a high bioconcentration factor (BCF) and low translocation factor (TF) have the potential for phytostabilization while plants with both BCFs and TFs greater than one have the potential to be used for phytoextraction. In this study, shoots and roots of the 12 plant species and the associated soil samples were collected. The collected samples were then analyzed by measurement of total concentrations of trace elements (Pb, Zn, Mn and Fe) using atomic absorption spectrophotometer. Simultaneously, BCF and TF parameters were calculated for each element. Results showed that although samples suitable for phytoextraction of Pb, Zn, Mn and Fe and phytostabilization of Fe were not detected, Scrophularia scoparia was the most suitable for phytostabilization of Pb, Centaurea virgata, Echinophora platyloba and Scariola orientalis had the potential for phytostabilization of Zn and Centaurea virgata and Cirsium congestum were the most efficient in phytostabilization of Mn. Present study showed that native plant species growing on contaminated sites may have the potential for phytoremediation.     

Groundwater hydrochemistry and soil pollution in a catchment affected by an abandoned lead–zinc mine: functioning of a diffuse pollution source

The importance of polluted alluvial soils as a potential diffuse source of heavy metals was investigated in a catchment of the Matylda stream affected by an abandoned lead and zinc ore mine in Upper Silesia, southern Poland. This was attempted by means of standard groundwater analyses performed together with measurements of Cd, Pb, Zn, Fe and Mn concentrations in soil and groundwater. The Matylda stream, receiving mine water, was converted in the 20th century into a straight channel directed in its middle reach over the valley bottom. This changed the drainage direction of the Matylda stream water. During mining operations, groundwater seepage, combined with surface drainage by shallow ditches caused pollution of sandy soils exceeding over 100 mg/kg of Cd, 24% of Zn and 4% of Pb at surface or subsurface soil horizons, and reaching at least 60 cm in depth. After mine closure in the 1970s, the network of ditches appears to be a source of Ca, Mg, chlorides, carbonates and nitrates, as indicated by the more or less regular increase of these major ion concentrations in groundwater down ditches. Whereas, the ditches are a sink rather than a source of zinc, cadmium and lead in permanently dry reaches, or transition zones in reaches with surface water flowing periodically. The metal concentrations and distribution in soil and groundwater suggest the slow mobilization of heavy metals stored in the valley bottom and the minor importance of soil as a diffuse source for surface water pollution.     

Soil heavy-metal speciation and wheat phytotoxicity in the vicinity of an abandoned lead–zinc mine in Shangyu City,eastern China

Sixteen soil samples were collected from the vicinity of an abandoned lead–zinc mine in Shangyu City, eastern China, and the heavy-metal speciation and wheat phytotoxicity in the soils were studied. The results showed that the concentrations of free Cu²⁺, Zn²⁺, Cd²⁺ and Pb²⁺ were highly variable and ranged from <0.01 to 0.32, 0.06 to 10.62, <0.01 to 1.40 and 0.02 to 37.10 μmol l⁻¹, respectively. The concentrations of soluble Cu, Zn, Cd and Pb ranged from 0.38 to 3.24, 0.72 to 78.74, <0.01 to 1.95 and 0.15 to 639.34 μmol l⁻¹, respectively. The general trend of mean solid/liquid partition coefficient and percentage of free metal ion to total soluble metal concentration were Cu > Pb > Zn > Cd and Cd > Zn > Cu > Pb, respectively. Stepwise multiple linear regression with pH, log(total metal) and log(organic matter) showed that log(total metal) was an important factor that controlled log(free metal ion) and log(soluble metal). Of the variability in log(free Cu²⁺), log(free Cd²⁺) and log(free Pb²⁺), 55.2, 58.6 and 64.3% could be explained by log(total Cu), log(total Cd) and log(total Pb) alone, respectively. Of the variability in log(soluble Cu) and log(soluble Cd), 77.1 and 72.5% could be explained by log(total Cu) and log(total Cd) alone, respectively. Wheat root length was controlled by the various metals with different free and soluble concentrations, and 99.2% of the variability in root length could be explained by concentrations of free and soluble Pb, soluble Cu and total Zn in the soils.     

Lead, zinc and cadmium accumulation in herbaceous species and soils in Lanping Pb/Zn mining area,Yunnan Province, China

A field survey of soils and herbaceous species growing in the Lanping Pb/Zn mining area in Yunnan Province, China, was conducted. Two major mining areas, Jiayashan and Beichang, were selected to investigate soil properties, herbaceous distribution and hea…     

Research on natural plants in the lead/zinc mine in northwestern Guizhou Province

A study of soils and four flourish plants in the heavy metal polluted area by lead/zinc mine in northwestem Guizhou Province. In this study four plants were collected, the species were： Sambucus Chinensis Linn, lxeris gracilis （DC.） stebb, Buddlej daxidii Franch.ex.sinarum lmp. and Senecio scandens. The fractions of heavy metals in the soil were distinguished by the short sequential extraction procedure （I. Maiz, 1997）, the available fractions and residual fractions of heavy metals in the soil could be separated. The plant digestion was effected by means of the microwave digest system （Durali Mendil, 2004）. In each step Pb, Zn and Cd were analyzed by FAAS. This study analyzed the heavy metals （Pb, Zn, Cd） contents of the soil and plant. It is found that the contents in the plant increased linearly with heavy metal concentrations in soil. The concentrations of Pb, Zn, Cd in the four plants follow the order of Zn〉Pb〉Cd. Sambucus Chinensis Linn and lxeris gracilis （DC.） stebb were proved to have good metal-enrichment and transport ability for heavy metals in the soil.     

The mechanisms of paragenesis and separation of silver, lead and zinc in hydrothermal solutions

On the basis of an experimental study and thermodynamic calculation, the mechanisms of paragenesis and separation of silver, lead and zinc in the hydrothermal system have been studied. At acidic to nearly neutral pH, their chloride complexes are stable, and among them the chloride complexes of zinc are most stable. And the sulfide complexes are the dominant species at nearly neutral to alkaline pH,while the sulfide complexes of silver are most stable. With decreasing temperature, [ Cl^-] ,fO2, and increasing pH, the solubilities of silver, lead and zinc will decrease, leading to their deposition and separation. For sulfide complexes, the concentrations of reduced sulfur and pH are two important factors affecting their stabilities. Complexes of different forms and stabilities respond to the variation of conditions to different extents, which gave rise to the paragenesis and separation of silver, lead and zinc in the whole ore-forming process of dissolution, transport and deposition.     

Accumulation patterns of Cu and Ni for Indigofera melanadenia and Tephrosia longipes plant species growing in Cu–Ni mining area in Botswana

Indigofera melanadenia and Tephrosia longipes plant species, collected from Cu–Ni mining area, were evaluated for accumulation of Cu and Ni. The total and bioavailable concentrations of Cu and Ni in the host soils were also determined. Flame Atomic Absorption Spectrometry was used for all metal determinations. The total and bioavailable concentrations of Cu in the soils were in the range 900–9000 μg/g and 200–2000 μg/g respectively. For Ni, the total and bioavailable concentrations were in the range 900–2000 μg/g and ∼ 40–100 μg/g respectively. The concentrations of Cu and Ni in the leaves of I. melanadenia were higher than in the roots with a range 80–130 μg/g in the leaves and 20–80 μg/g in the roots for Cu and a range of 150–200 μg/g in the leaves and 20–60 μg/g in the roots for Ni. Concentration of Cu in T. longipes was in the range of 37–240 μg/g and 150–200 μg/g in the leaves and roots respectively while the concentration of Ni was 80–140 μg/g in the leaves and 25–100 μg/g in the roots. Results indicate that both species have a potential for accumulating Cu and Ni. Translocation factor, a ratio of shoots to roots metal concentration, was used to evaluate the translocation properties of the plants from roots to shoots. Translocation factors of the plants were ≥ 1 suggesting efficient translocation of metals from roots to shoots.     

Phytoremediation assessment of native plants growing on Pb–Zn mine site in Northern Tunisia

Pollution by heavy metals presents an environmental concern, and their toxicity threats soil, water, animals and human health. Phytoremediation can be used as a solution to remediate contaminated soils. The aim of this study was to identify native plants collected from tailings: material of Pb–Zn mine sites of Fedj Lahdoum and Jebel Ressas (two abandoned mines located, respectively, in the northwest of Tunisia and in the south of Tunis City). The tolerance of plant to heavy metals (lead, zinc and cadmium) is evaluated. Soil samples were collected and analyzed for Pb, Zn and Cd concentration. The total soil Pb, Zn and Cd are, respectively, reached 6132 mg kg^?1, 11,052 mg kg^?1 and it doesn’t exceed 479 mg kg^?1 for Cd. The highest content of Zn in plants was detected in shoots of Rumex bucephalophorus (1048 mg kg^?1), and the highest Pb concentration was detected in roots of Chrysopogon zizanioides (381 mg kg^?1), while for Cd Silene colorata it accumulated the highest content in roots (51 mg kg^?1). From all plants, only 12 have a translocation factor for Pb which is higher than one. Among all plants, only 17 have a translocation factor that is higher than one for Zn, while for Cd only 13 plants indicate TF > 1. As for the biological absorption coefficient, all samples indicate a rate which is lower than one. These plants can be primarily hyper accumulators and useful in remediation of lead- and zinc-contaminated soils after further biochemistry researches in mechanism of accumulation and translocation of heavy metals in plants.     

Lead isotopic and chalcophile element compositions in the environment near a zinc smelting–secondary zinc recovery facility,Palmerton, Pennsylvania,USA

The environment surrounding Palmerton, Pennsylvania is contaminated with Pb arising from primary Zn smelting and a process involving Zn recovery from electric arc steel furnace dusts. Lead isotope systematics have been used to distinguish primary Zn smelting Pb (²⁰⁶Pb/²⁰⁴Pb∼18.4–18.5) from electric arc furnace dust lead (²⁰⁶Pb/²⁰⁴Pb∼19.0–19.1). Primary Zn smelting is the dominant source of Pb in O2 horizon soils from undisturbed near-Palmerton locations, which contain up to 3570 ppm Pb and 782 ppm Cd. Soils from undeveloped near-Palmerton locations also exhibit unusually elevated concentrations of other sphalerite-derived chalcophilic elements (Se, Ag, In, Sb, Te, Au, Hg, Tl and Bi); indium concentrations of up to 17.0 ppm are observed therein. Residential soils and dusts from Palmerton contain Pb which is largely explainable via mixing of Pb from primary Zn smelting and electric arc furnace dusts. Approximately 80% of the Pb in airborne particulate matter sampled at Palmerton in 1991 is derived from electric arc furnace dusts, and atmospheric enrichment factors for Cu, Sb, Pb, and Bi are observed which confirm this major source contribution. Residential samples from a control location contain Pb which is less radiogenic than is found in Palmerton, and exhibit no unusual elevation in sphalerite elements. Lead source discrimination in the Palmerton environment via Pb isotopic and elemental constituents approaches result in parallel conclusions.     

Investigation of lead and zinc dispersion from an abandoned mine site at Tyndrum, Scotland, using tree bark measurements

Tyndrum was an industrial mining area from 1741 until the 1920s where the main ores extracted were lead sulphide （galena） and zinc sulphide （sphalarite）. Situated in central Scotland, the now deserted site is identified as a highly polluted, barren area where the original waste residues from the mine, an ore processing and a smelting site are clearly evident. Previous studies have suggested that high levels of lead and zinc contaminants are still dispersed from this former mine site, both atmospherically and through fluvial transport. For example, high concentrations of Pb, identified by its isotopic signature as originating in Tyndrum, have been found in sediments in Loch Tay, 25 km east of this area. This paper presents the results of a study of the occurrence and magnitude of airborne contamination by dispersion from the former mine site using measurements of metal concentrations in tree bark. These naturally occurring ‘bio monitors＇, which accumulate airborne materials including heavy metals, have become an effective alternative to the more costly air-filter system, which is restricted in scope and coverage. Bark samples were acquired from Scots pine （Pinus sylvestris） trees, which are abundant around the derelict mine site. Suitable locations were chosen to investigate atmospheric transport and deposition of contaminants within the area.     

Concentration and spatial variability of mercury and other heavy metals in surface soil samples of periurban waste mine tailing along a transect in the Almadén mining district (Spain)

Mercury (Hg) is one of the elements with increasing environmental significance. A total of 22 samples (soils, rocks and gels) were collected along a 6 km transect around the Valdeazogues River valley in the southwest of the Iberian Peninsula (Almadén, Spain). Samples were characterized by different soil types of depositional sequences associated with mining tailings, type and system tracts: 15 surface soil samples included in the transect; 3 of a Haploxerept soil profile developed on slates; 2 of quartzite and slates rocks (reference rocks in the area). Moreover, two of a gel substance (in the lower tract of the river). Soil samples were analyzed for Hg, Cu, Ni, Cr, V, Pb, Cd and As, as well as for organic matter, pH abrasion and calcium carbonate content. All samples were collected from the Almadén mining district. The level of occurrence of the elements (especially Hg) and the effect of some properties on its concentration distributions were investigated. The total mercury contents varied in the range 7,315–3.44 mg kg⁻¹. The mean concentration of total mercury in soils and rocks was 477.03 mg kg⁻¹dry mass. This value is very high compared to the regional background value of other areas. Only rarely is it higher than 1%: in one sample (7,315 mg kg⁻¹) it was almost eight times in comparison with the affected zones, with a high value of 1,000 mg kg⁻¹. Significant differences between samples were found in the total content of mercury. A large percentage of the samples registered detectable levels of V, Cr, Ni, Pb, As and Cu. Cd readings were below the detectable range for all samples tested. Cr mean concentration was 216.95 mg kg⁻¹ (minimun concentration 86, maximun 358); V mean concentration was 119.09 mg kg⁻¹ (minimun concentration 69, maximun 1,209); As mean concentration was 51.24 mg kg⁻¹ (minimun 13.3 and maximun 319.4); Ni mean concentration was 45.64 mg kg⁻¹ (minimun concentration 21.2 and maximun 125.6); Cu mean concentration was 33.25 mg kg⁻¹ (minimun concentration 19.3 and maximun 135); Pb mean concentration was 15.19 mg kg⁻¹ (minimun 1.12 and maximun 1013). Metal distribution generally showed spatial variability ascribed to significant anthropogenic perturbation by mining tailing type. Hg showed vertical profile characterized by surface enrichment, with concentrations in the upper layer (93.7–82.2 mg kg⁻¹ in front of 3.4 of the rock value) exceeding, in several occasions, the background value. The results obtained denote a potential toxicity of some heavy metals in some of the studied samples. Water-soluble mercury could enter the aquatic system and accumulate in sediments. Mercury and other heavy metals contamination depended on the duration and intensity of mining activities.     

Lead and nickel biosorption with a fungal biomass isolated from metal mine drainage: Box–Behnken experimental design

The Pb(II) and Ni(II) biosorption of a fungal biomass isolated from mine drainage of metal-processing industries in Balya (Bal?kesir province, Turkey) was optimized using a response surface methodology by altering parameters such as pH, initial metal concentration, contact time and biosorbent dosage. This strain was shown to be highly similar to Penicillium sp. Furthermore, zeta potential measurements and Fourier transform infrared spectroscopy were performed to understand the adsorption mechanism. A Box–Behnken design with 29 experiments was used to evaluate the interactions between independent variables. The results showed that the fungal biomass isolated from the metal mine drainage could have a significant environmental impact through the biosorption of Pb(II) and Ni(II) in waters polluted with heavy metals, particularly in the drainage from metal mines. The maximum removal values were 76 and 47 % at pH 4.5 for both Pb(II) and Ni(II), with 123 and 33 mg/L initial metal concentrations, 65 and 89 min contact times and 0.2 and 1.6 g/L biosorbent, respectively.     

Transformation of organic carbon and its potential impact on lead weathering in firing range soils

Lead （Pb） is normally considered as a trace element in soils and sediments for geochemical study. However, the concentration of Pb in firing range soils is generally so high that it should be considered as a major element during the evaluation of the soil geochemical properties. Soil organic matter （SOM） has been reported as one of the major factors to expedite the corrosion of metallic lead （Pb） in acidic and organic-rich soils. The main impacts of SOM on the fate and transport of Pb in firing range soils lie in the following two aspects; （1） the complexation of organic matter with Pb, which has received lots of attention, and; （2） changes in soil redox potential due to the transformation of SOM and its subsequent impact on Pb speciation, which has rarely been investigated. Soils from 6 different firing ranges are selected for this study. These samples have been stored under a closed condition for more than 3 years. The soil moisture contents were well-retained, as all the samples were kept in closed plastic buckets. The analytical data showed that the summation of the soil total organic carbon content （TOC） and inorganic carbon contents （TIC） were consistent with soil total carbon contents （TC） measured in previous years, although the TOC and TIC contents have changed respectively after years of storage. In general, it is observed that the soil TOC decreased against an increase of TIC. The mass balance on such a transformation suggested a major conversion of organic carbon （Corg） to inorganic carbon （CO3^2-） in the stored soils.     

Mercury in river sediments, floodplains and plants growing thereon in the drainage area of the Idrija mine, Slovenia

Half a millennium mercury production at Idrija is reflected in increased mercury contents in all environmental segments. The bulk of roasting residues from the middle of the 19th century to 1977 was discharged directly into the Idrijca River, and the material was carried at high waters to the Soca River and farther into the Adriatic Sea. It has been estimated that 45500 tons of mercury were emitted into the environment during the operating period of the mine, which ceased production in 1994. In the lower reaches of the Idrijca the riverine deposits with high mercury contents have been, and will be in the future a source of mercury polluted sediment. Stream sediments were monitored at the same locations along the Idrijca and Soca rivers （70 kin） every 5 years since 1991 （1991-2005）. Grain size distribution was determined by dry sieving and fractions for geochemical analysis were prepared （〈0.04 and 〈0.125 mm）. Soils on river terraces were sampled at 5 localities in the lower course of Idrijca. At two locations of the terrace profiles the samples of averaged meadow forage and plantain （Plantago lanceolata） were collected within a 50-meters radius. We found that there was no decrease in mercury concentration in active river sediments during the last 20 years. Upstream from the Idrija Town the mercury concentrations in active river sediments vary from 1 to 10 mg/kg （average 3.3 mg/kg）. From Idrija to Spodnja Idrija the mercury concentrations increase extremely and vary greatly （32-4,121 mg/kg, the average is 734 mg/kg）. From Spodnja ldrija to the Idrijca-Soca confluence is the average 218 mg/kg, and 57 mg/kg downstream in the Soca River sediments.     

Nature and practical implications of heterogeneities in the geochemistry of zinc-rich,alkaline mine waters in an underground F–Pb mine in the UK

Water pollution arising from base metal sulphide mines is problematic in many countries, yet the hydrogeology of the subsurface contaminant sources is rarely well-characterized. Drainage water pumped from an active F–Pb mine in northern England has unusual chemistry (alkaline with up to 40 mg.l⁻¹ Zn) which profoundly impacts the ecology of the receiving watercourse. Detailed in-mine surveys of the quantity and quality of all ground water inflows to the mine were made. These revealed major, temporally persistent heterogeneities in ground water quality, with three broad types of water identified as being associated with distinct hydrostratigraphic units. Type I waters (associated with the Firestone Sill aquifer) are cool (<10°C), Ca–HCO₃–SO₄ waters, moderately mineralized (specific electrical conductance (SEC)≤410 μS.cm⁻¹) with <4 mg.l⁻¹ Zn. Type II waters (associated with the Great Limestone aquifer) are warmer (≈15°C), of Ca–SO₄ facies, highly mineralized (SEC≤1500 μS.cm⁻¹) with ≤40 mg.l⁻¹ Zn. Type III waters (in the deepest workings) are tepid (>18°C), of Ca–HCO₃–SO₄ facies, intermediately mineralized (SEC≤900 μS.cm⁻¹) with ≤13 mg.l⁻¹ Zn, and with significant Fe (≤12 mg.l⁻¹) and Pb (≤8 mg/l). Monotonic increases in temperature and Cl⁻ concentration with depth contrast with peaks in total mineralization, SO₄ and Zn at medium depth (in Type II waters). Sulphate, Pb and Zn are apparently sourced via oxidation of galena and sphalerite, which would release each metal in stoichiometric equality with SO₄. However, molal SO₄ concentrations typically exceed those of Pb and Zn by 2–3 orders of magnitude, which mineral equilibria suggest is due to precipitation of carbonate “sinks” for these metals. Contaminant loading budgets demonstrate that, although Type II waters amount to only 25% of the total ground water inflow to the mine, they account for almost 60% of the total Zn loading. This observation has important management implications for both the operational and post-abandonment phases of the mine life cycle.     

Genesis of fahlore in the Tianbaoshan lead–zinc deposit,Sichuan Province,China: a scanning electron microscopy–energy dispersive spectroscopy study

The Tianbaoshan deposit, located in the southwestern part of the Yangtze Block, is a representative Pb–Zn deposit in the Sichuan–Yunnan–Guizhou Pb–Zn metallogenic province. The Pb–Zn orebodies are hosted in the upper Sinian Dengying Formation dolostone. The predominant minerals are sphalerite, galena, pyrite, chalcopyrite, quartz, and calcite with minor arsenopyrite, fahlore, and dolomite. The deposit is characterized by relatively strong Cu mineralization. However, the relationship between Pb–Zn and Cu mineralization is unknown. We analyzed the mineralogy and composition of fahlore, chalcopyrite, arsenopyrite, sphalerite, and galena using scanning electron microscopy–energy dispersive spectroscopy, with the aim of providing new evidence for the genesis of the Pb–Zn–(Cu) ore. The results show that the Cu ore in the deposit is dominated by chalcopyrite and fahlore, both of which formed before or during the Pb–Zn ore-forming stage. The fahlore showed dramatic compositional variation and was characterized by negative correlations between Ag and Cu, and between As and Sb, suggesting substitution of Ag for Cu, and that As and Sb substitute in the same site in the fahlore lattice. Based on backscattered electron images and composition, the fahlore was divided into two types. Type I fahlore crystallized early and is characterized by enrichment of Cu and depletion in Ag and Sb. Type II fahlore formed after Type I, and is rich in Ag and poor in Cu and As. Moreover, galena and fahlore are the host minerals of Ag. The variation of valence state with As host mineral—from fahlore to arsenopyrite—indicates the metallogenic environment changed from relatively oxidizing to reducing with a high pH. In the light of Gibbs energies of reciprocal reactions and isotherms for cation exchange, the composition of the fahlore implies its ore-forming temperature was lower than 220 °C, corresponding with typical Mississippi Valley-type (MVT) deposits. Based on the geologic character and geochemical data of this deposit, we suggest that the Tianbaoshan deposit belongs to the MVT deposit category.     

Controlling factors and environmental implications of mercury contamination in urban and agricultural soils under a long-term influence of a chlor-alkali plant in the North–West Portugal

This study aims at assessing the extent of total mercury (Hg) contamination in urban and agricultural soils under long-term influence of a chlor-alkali plant, located at about 1 km away from a town centre. Moreover, it aims at identifying the main factors controlling Hg contents’ distribution and associated potential hazards to environment and human health. The median value of total Hg for soil surface layer (0–10 cm) was 0.20 mg/kg (data ranging from 0.050 to 4.5 mg/kg) and for subsurface layer (10–20 cm) 0.18 mg/kg (data ranging from 0.046 to 3.0 mg/kg). The agricultural area showed higher Hg concentrations (ranging from 0.86 to 4.5 mg/kg) than urban area (ranging from 0.05 to 0.61 mg/kg), with some results exceeding target values set by the Dutch guidelines. Mercury concentrations observed in the studied area are more likely to be associated with the influence of the chlor-alkali plant and with the use of historically contaminated sludges and water from a nearby lagoon in agriculture, than to the impacts of urban development. The statistical correlations between Hg concentrations and soil properties suggest that anthropogenic metal sources should influence the spatial distribution more than the geological properties. Although the Hg emissions were drastically reduced 10 years ago, the area under influence of the chlor-alkali plant is still facing potential health and environmental threats arising from soil contamination.