Pb-Zn Mining Area Research Articles

Isolation, characterization, and selection of heavy metal-resistant and plant growth-promoting endophytic bacteria from root nodules of Robinia pseudoacacia in a Pb/Zn mining area

Multiple heavy metals (HMs) commonly coexist in mining areas, which highlights the necessity to select multiple HM-resistant plant growth-promoting bacteria for improving phytoremediation efficiency. In this study, we isolated and characterized 82 endophytic bacteria from the root nodules of black locust (Robinia pseudoacacia) grown in a Pb-Zn mining area. There were 80 isolates showing resistance to four HMs, 0.01–18.0 mM/L for Cd, 0.2–40.0 mM/L for Zn, 0.3–2.2 mM/L for Pb, and 0.2–1.4 mM/L for Cu. Indole-3-acetic acid production, siderophore production, and 1-aminocyclopropane-1-carboxylate deaminase activity were detected in 43, 50, and 17 isolates, respectively. Two symbiotic isolates selected with the highest potential for HM resistance and PGP traits, designated Mesorhizobium loti HZ76 and Agrobacterium radiobacter HZ6, were evaluated for promotion of plant growth and metal uptake by R. pseudoacacia seedlings grown in pots containing different levels of Cd, Zn, Pb, or Cu. HZ76 significantly increased plant shoot biomass, while HZ6 did not, compared with non-inoculated controls. The results indicate that inoculation with HZ76 or HZ6 relieved HM stress in the plants, depending on the type and concentration of HM in the treatment. Mesorhizobium loti HZ76 may be a better candidate for application in phytoremediation than A. radiobacter HZ6. The microsymbiosis between HM-resistant rhizobia and R. pseudoacacia is an interesting mutualistic system for phytoremediation in mining areas contaminated with multiple HMs.

Heavy Metal Pollution and Ecological Risk Assessment of the Agriculture Soil in Xunyang Mining Area, Shaanxi Province, Northwestern China.

Mining is considered to be one of the most significant sources of environmental pollution with regard to heavy metals. Mineral mining causes large quantities of mercury, cadmium, and other elements to be released into the environment and naturally poses a serious threat to environment. This paper will analyze the pollution status of agricultural soil caused by the mining of heavy metals in various mining areas in the Xunyang County in the Shaanxi Province of China, an area in famous for its resource mining. Equally, it will look at the potential ecological risk assessment process that is used to analyze the ecological risks of mining heavy metals in agricultural soil located in the surrounding areas. Based on the soil investigation, As pose a moderate ecological risk on the Au mining area. In addition, the Hg metals pose a significantly high potential ecological risk and Cd metals pose a considerable potential ecological risk on the Hg mining area. In the Pb-Zn mining area, a significantly high potential ecological risk was mainly posed by Cd. These results suggest that many heavy metals pose a high potential ecological risk on the agricultural soil in these three mining areas in the Xunyang County, and may cause elevated heavy metal contents in crops, eventually jeopardizing the health of local residents who consume food grown in polluted soil.

Evaluation of Heavy Metals in Stream Sediments from Abakaliki Pb – Zn Ore Mining Areas of Ebonyi State, Nigeria

This research is an assessment of toxic metals in stream sediments from the Abakaliki Pb-Zn mine area of Ebonyi state. Heavy metals in stream sediment samples were analysed using Atomic Absorption Spectrometer (AAS). Physicochemical parameters were determined show that pH is generally low (3.65) resulting from the dissolution of the sulphide Ore. The heavy metal mean trend indicates that Fe > Zn >Pb> Cr >Cu > Ni > AS > Cd in the stream sediment samples. Fe, Zn, Cu, Pb and Cr were observed to be high. The variations for the heavy metals suggest that mining operation is responsible for the distribution and redistribution of chemical elements. The values of contamination factor for the stream sediment indicate moderate contamination for Cd, As and Ni while Fe, Zn, Pb, Cu and Cr show very high contamination. The result of enrichment factor (EF) using Fe concentration as normalizing value show that Ni, Cd, Cr, As, and Cu have depletion to mineral enrichment while Pb and Zn show moderate enrichment. The result of the Correlation analysis and principal component analysis ( R- Mode and Q-mode) applied to the data analysis show that Zn, Pb, Cd, Cu, and Cr heavy metals originated from similar sources but may have been influenced by mining operation while Ni and As are attributed to a geogenic source. Proper sewage disposal practice and soil remediation are recommended.

Use of magnetic biochars for the immobilization of heavy metals in a multi-contaminated soil

Modified biochars, including magnetic biochars, have been tested in water for the removal of inorganic pollutants. However, at present it is unknown if they possess benefits over conventional biochar materials in relation to land remediation. A paddy soil was collected near Liantang village in Lechang Pb-Zn mine area in Guangdong Province (China). The soil was polluted with Cd, Cu, Zn and Pb, with total contents of 1.4mg/kg, 80mg/kg, 1638mg/kg and 2463mg/kg, respectively. We prepared magnetic and conventional biochar from two feedstocks (poultry litter and Eucalyptus) at a temperature of 300 and 500°C. A sequential extraction procedure for the speciation of heavy metals and a phytotoxicity test using rice were performed. Acid-soluble Cd in soils amended with PLB was 8 to 10% lower than in the control polluted soil. This figure was 27 to 29% for acid-soluble Zn and 59 to 63% for acid-soluble Cu. In some cases, differences were found between the heavy metal fractionation in samples amended with magnetic and conventional biochars. Plant biomass was unaffected by most treatments, but increased by 32% in the treatments containing magnetic poultry litter biochar. Our study shows that a careful choice of feedstock is of utmost importance for successful containment of heavy metals in a multi-contaminated mining area soil. An appropriate choice of feedstock (in the case of this study poultry litter vs. eucalyptus) was more determinant with respect to the mobility of pollutants than altering pyrolysis temperature or modifying surface properties through magnetization. However, surface modification through magnetization can have a significant impact on plant yield and offer comparative advantages in the management of some degraded landscapes.

Origin and spatial distribution of heavy metals and carcinogenic risk assessment in mining areas at You'xi County southeast China

An extensive study on the spatial distribution and source apportionment of heavy metals in soils and so by risk assessment at You'xi County, a major Pb–Zn mining area southeast China, was conducted in this contribution. A total of 93 soil samples were examined with the concentration of heavy metals (As, Cd, Cr, Cu, Hg, Pb, and Zn), pH, and soil organic matter (SOM) contents by using geostatistical approaches combined with geographic information system (GIS) analysis. The mean values of heavy metals were determined to be 7.9±5.8, 12.8±14.1, 80.4±42.0, 34.4±45.0, 0.12±0.13 368.5±873.6, and 369.6±505.5mgkg−1 (mean±SD) for As, Cd, Cr, Cu, Hg, Pb, and Zn, respectively. Contents of all heavy metals present in the study area were considerably higher than their background values of provincial and national standards except for As. A principle component analysis revealed the main origin of heavy metals: soil parent materials for Cu, Pb, and Zn; atmospheric deposition during mining processes for Cr, and Hg; and human farming activities for Cd. Carcinogenic risk was assessed with an average value of 69.3×10−6mgkg−1, suggesting an average of 69 individuals per million people being predisposed to cancer. Meanwhile, the identification of heavy metal sources in agricultural soils might be beneficial to local soil protection and soil quality improvement.

Distribution and Risk Assessment of Heavy Metals in Soils from a Typical Pb-Zn Mining Area

Distribution and Risk Assessment of Heavy Metals in Soils from a Typical Pb-Zn Mining Area

Pb – Zn - Cd ACCUMULATOR PLANTS GROWN AROUND THE GÖRGÜ(YESİLYURT) Pb – Zn MINE, -MALATYA, TURKEY

A study was carried out to identify Cd, Pb and Zn concentrations which exist in the roots and stems of Astragalus pycnocephalus Fischer and Verbascum euphraticum L. plants which grow in the Görgü Pb-Zn mining area. A total of 60 samples were collected, 30 samples from plants and 30 samples from the soils where the plants grow. When the anaytical results gained are statistically examined, according to correlation coeffi cients graphic between the soil and plant, fi nding positive correlation between (A. Pycnocephalus) soil-root (Cd, r =0.77), soil-stem (Cd, r =0.86) and soil-stem (Pb, r =0.77) could mean that these could be indicator plants and can be used for remediation of the soils polluted by Cd and Pb metals. It is observed that the metallic concentration times values of the plants in this study taken from polluted areas compared to the plants taken from unpolluted areas, are quite high in total 44 samples. Transition factor is >1 in some sample locations and range between 0.13 and 2.07. Enrichment coeffi cients is>1 for the location of V11 (Cd, root/soil). A. Pycnocephalus and V. Euphraticum, in some locations, according to transition factor, enrichment coeffi cients, times values and element concentrations could be identifi ed as accumulator/hyperaccumulator for Cd, Pb and Zn elements..

Accumulation Characteristics and Chemical Speciation of Cd, Zn and Pb in Soils Impacted by a Pb-Zn Mining Area

Accumulation Characteristics and Chemical Speciation of Cd, Zn and Pb in Soils Impacted by a Pb-Zn Mining Area

Multivariate factor assessment for lithogenic and anthropogenic distribution of macro and trace elements in surface water. Case study: Basin of the Bregalnica river, Republic of Macedonia

<p class="Default">This study presents the spatial distribution of 69 elements in the surface water of the Bregalnica river basin. The concentration of elements was determined using inductively coupled plasma with mass spectrometry (ICP-MS) and inductively coupled plasma - atomic emission spectrometry (ICP-AES). The data summary results were reduced with the application of multivariate factor analysis, whereupon three dominant geochemical associations were obtained: F1 (Ca-K-Mg-Na-Ba-Li-Mn-Sr-V), F2 (Al-Fe) and F3 (Sb). Anthropogenic enrichments of Pb and Zn occur in the Pb-Zn mine area. The obtained data exceeded the maximum allowed concentrations in accordance with the national regulation for surface water quality. Trace elements including REEs were significantly correlated with the dominant geological formations characteristic of the different sub-regions in the investigated area.</p>

Concentrations, spatial distribution, and risk assessment of soil heavy metals in a Zn-Pb mine district in southern China.

China is one of the largest producers and consumers of lead and zinc in the world. Lead and zinc mining and smelting can release hazardous heavy metals such as Cd, Pb, Zn, and As into soils, exerting health risks to human by chronic exposure. The concentrations of Cd, Zn, Pb, and As in soil samples collected from a Pb-Zn mining area with exploitation history of 60years were investigated. Health risks of the heavy metals in soil were evaluated using US Environmental Protection Agency (US EPA) recommended method. A geo-statistical technique (Kriging) was used for the interpolation of heavy metals pollution and Hazard Index (HI). The results indicated that the long-term Pb/Zn mining activities caused the serious pollution in the local soil. The concentrations of Cd, As, Pb, and Zn in topsoil were 40.3±6.3, 103.7±37.3, 3518.4±896.1, and 10,413±2973.2mg/kg dry weight, respectively. The spatial distribution of the four metals possessed similar patterns, with higher concentrations around Aayiken (AYK), Maseka (MSK), and Kuangshan (KS) area and more rapidly dropped concentrations at upwind direction than those at downwind direction. The main pollutions of Cd and Zn were found in the upper 60cm, the Pb was found in the upper 40cm, and the As was in the upper 20cm. The mobility of metals in soil profile of study area was classed as Cd>Zn≫Pb>As. Results indicated that there was a higher health risk (child higher than adult) in the study area. Pb contributed to the highest Hazard Quotient (57.0~73.9%) for the Hazard Index.

Ecotoxicological risks of the abandoned F-Ba-Pb-Zn mining area of Osor (Spain).

Due to its potential toxic properties, metal mobilization is of major concern in areas surrounding Pb-Zn mines. In the present study, metal contents and toxicity of soils, aqueous extracts from soils and mine drainage waters from an abandoned F-Ba-Pb-Zn mining area in Osor (Girona, NE Spain) were evaluated through chemical extractions and ecotoxicity bioassays. Toxicity assessment in the terrestrial compartment included lethal and sublethal endpoints on earthworms Eisenia fetida, arthropods Folsomia candida and several plant species, whereas aquatic tests involved bacteria Vibrio fischeri, microalgae Raphidocelis subcapitata and crustaceans Daphnia magna. Total concentrations of Ba (250-5110mgkg-1), Pb (940 to >5000mgkg-1) and Zn (2370-11,300mgkg-1) in soils exceeded intervention values to protect human health. Risks for the aquatic compartment were identified in the release of drainage waters and in the potential leaching and runoff of metals from contaminated soils, with Cd (1.98-9.15µgL-1), Pb (2.11-326µgL-1) and Zn (280-2900µgL-1) concentrations in filtered water samples surpassing US EPA Water Quality Criteria (2016a, b). Terrestrial ecotoxicity tests were in accordance with metal quantifications and identified the most polluted soil as the most toxic. Avoidance and reproduction tests with earthworms showed the highest sensitivity to metal contamination. Aquatic bioassays performed in aqueous extracts from soils confirmed the results from terrestrial tests and also detected toxic effects caused by the mine drainage waters. Algal growth inhibition was the most sensitive aquatic endpoint. In view of the results, the application of a containment or remediative procedure in the area is encouraged.

Multivariate statistical approach to identify metal contamination sources in agricultural soils around Pb–Zn mining area, Isfahan province, Iran

The aims of this study are to evaluate the extent of toxic metal pollution in agricultural soils near the Pb–Zn mining area (Irankuh mining area, Isfahan Province, Iran), and to find out their origins. A total of 32 grab topsoil samples collected from an agricultural field were analyzed for toxic metals including Pb, Zn, Ni, Cu, and Cd using atomic absorption spectrophotometry. The results of the analyses showed that the mean concentrations of Pb, Zn, Ni, Cu, and Cd were 51.80, 60.34, 35.75, 12.05, and 1.38 mg/kg, respectively. Multivariate analysis including correlation coefficient analysis, factor analysis and cluster analysis were used to examine the relationship between the toxic elements and also identify their possible pollution sources. According to the factor and cluster analyses, the 5 toxic metals were classified into three groups. The first group comprised of Cu, Zn, and Pb; while the second and third groups were made up of Ni and Cd, respectively. The average value of Geoaccumulation index (I geo) for Ni, Zn, Cu, Pb, and Cd in the soil samples were obtained to be 0.23, 0.80, 0.96, 1.60, and 4.62, respectively. Geoaccumulation index evaluation indicated that the agricultural soil samples were moderately polluted with respect to Zn, Cu, and Ni; moderately to strongly polluted with respect to Pb; and heavily to extremely polluted with respect to Cd. Results of this study can be used for planning and performing appropriate future remediation activities at the site.

Influence of Combined Soil Heavy Metal Pollution on Soil Enzyme Activity in the Pb–Zn Mining Area of Southern Shaanxi

Influence of Combined Soil Heavy Metal Pollution on Soil Enzyme Activity in the Pb–Zn Mining Area of Southern Shaanxi

Metal speciation in agricultural soils adjacent to the Irankuh Pb–Zn mining area, central Iran

Mining activities are a significant potential source of metal contamination of soils in surrounding areas, with particular concern for metals dispersed into agricultural area in forms that are bioavailable and which may affect human health. Soils in agricultural land adjacent to Pb–Zn mining operations in the southern part of the Irankuh Mountains contain elevated concentrations for a range of metals associated with the mineralization (including Pb, Zn and As). Total and partial geochemical extraction data from a suite of 137 soil samples is used to establish mineralogical controls on ore-related trace elements and help differentiate spatial patterns that can be related to the effects of mining on the agricultural land soils from general geological and environmental controls. Whereas the patterns for Pb, Zn and As are spatially related to the mining operations they display little correlation with the distribution of secondary Fe+Mn oxyhydroxides or carbonates, suggesting dispersion as dust and in forms with limited bioavailability.

Ore metal concentration in soil and stream sediments of Pb-Zn mining area in North Vietnam

Ore metal concentration in soil and stream sediments of Pb-Zn mining area in North Vietnam

Multivariate statistical analysis of heavy metals in soils of a Pb–Zn mining area, India

Surface soil samples collected from a Pb and Zn mining area in India were subjected to multi-elemental analysis by using inductively coupled plasma-atomic emission spectrometry. Multivariate statistical methods such as principal component analysis and cluster analysis, coupled with correlation coefficient analysis, were used to analyze the data and to apportion the possible sources of elements in soils of a metal mining area. Soils in this area have elevated heavy metal concentrations especially Pb, Zn, Mn, Cu, As, and Tl. Using principal component (PC) analysis, six components were extracted, out of which two PCs explaining 50.12% of total variance are more important. The first principal component with a high contribution of Ag, As, Be, Cd, Co, Cu, Mg, Mn, Ni, Pb, and Zn was deemed to be technogenic/anthropogenic component, and the second principal component, with high loadings for the five discerning variables (Al, Be, Cr, K, Li), was considered as lithogenic component. The third component having strong loadings of Ba, Ca, K, and Na is supposed to have a mixed origin (lithogenic as well as technogenic). Electrical conductivity and total organic matter were not correlated with any element and also have a strong loading in the fifth component which is probably the biomass and ions present in these soils. The findings of the principal component analysis were also substantiated by the cluster analysis. The present study would not only enhance our knowledge regarding the soil pollution status in the study area but would also provide us information to manage the sources of these elements in the study area.

Native Plant Communities in an Abandoned Pb-Zn Mining Area of Northern Spain: Implications for Phytoremediation and Germplasm Preservation

Plants growing on metalliferous soils from abandoned mines are unique because of their ability to cope with high metal levels in soil. In this study, we characterized plants and soils from an abandoned Pb-Zn mine in the Basque Country (northern Spain). Soil in this area proved to be deficient in major macronutrients and to contain toxic levels of Cd, Pb, and Zn. Spontaneously growing native plants (belonging to 31 species, 28 genera, and 15 families) were botanically identified. Plant shoots and rhizosphere soil were sampled at several sites in the mine, and analyzed for Pb, Zn and Cd concentration. Zinc showed the highest concentrations in shoots, followed by Pb and Cd. Highest Zn concentrations in shoots were found in the Zn-Cd hyperaccumulator Thlaspi caerulescens (mean = 18,254 mg Zn kg−1 DW). Different metal tolerance and accumulation patterns were observed among the studied plant species, thus offering a wide germplasm assortment for the suitable selection of phytoremediation technologies. This study highlights the importance of preserving metalliferous environments as they shelter a unique and highly valuable metallicolous biodiversity.

Mercury contamination and its potential health effects in a lead–zinc mining area in the karst region of Guangxi, China

Mercury contamination of the environment is of worldwide concern because of its global presence and its potent neurotoxicity. Mining, smelting and the electronics industry are the main sources of Hg pollution. However, few studies have been performed to investigate systemic Hg contamination in metal mining regions. In this study, concentrations of Hg in air, farmland soil, and crops were measured in a Pb–Zn mining area in the karst region of Guangxi, China. Key factors that could affect Hg distribution, such as the fate of waste ore and waste residue, were analyzed. Geo-statistical methods were adopted to analyze the characteristics of spatial structure and distribution of Hg. The results show that Hg contamination in this region is serious. The total mercury (T-Hg) content is far higher than the Level II Limit Value of Chinese Soil Standards of 0.30 mg kg−1, showing obvious directional characteristics from WNW to ESE. Highest Hg concentrations were found in the WNW portion of the study area. The contamination of paddy soil is higher than that in dry farmland soil. The vertical distribution of T-Hg and its decrease with depth suggest that the important sources are waste water irrigation and the improper disposal of the waste ore and waste rock. The T-Hg concentrations in the agricultural products examined exceed the Chinese tolerance value (0.02 mg kg−1 for rice and 0.01 mg kg−1 for vegetables), indicating the seriousness of the problem. The ecological environment and the safety of food grown in this mining area are being affected, with the result that human health is possibly being affected.

Translocation and Accumulation of Boron in Roots and Shoots of Plants Grown in Soils of Low Boron Concentration in Turkey's Keban Pb-Zn Mining Area

Boron (B) concentrations were investigated in both shoots and roots of Euphorbia macroclada, Verbascum cheiranthifolium, and Astragalus gummifer grown in soil of the Keban, Turkey, Lead–zinc–copper–fluoride mining area, which has an arid climate. Soil B concentrations were also investigated. Plants and their associated soil samples were collected and analyzed by Inductively Coupled Plasma–Mass Spectrometry (ICP-MS). Total B concentrations of soils in the study area were very low (mean: 4.97 mg kg−1) as compared with those in surface soils in other countries. Boron concentrations of plant organs were several times higher than those in their associated soils. The mean values of B concentrations in roots of E. macroclada, V. cheiranthifolium, and A. gummifer were 25, 70, and 69 mg kg−1, respectively, while those in shoots were 75, 115, and 77 mg kg−1, respectively. Results indicate that roots and shoots of plants grown in soils with low B concentrations can be used both as biomonitors for environmental contamination and biogeochemical indicators for B.

Identification of a Cd accumulator Conyza canadensis

One of key steps of phytoremediating heavy metal contaminated soils is still the identification of hyperaccumulator and accumulator. In a former published article, Conyza canadensis L. Cronq. expressed some basic properties of Cd-hyperaccumulators. In this study, concentration gradient experiment and two sample-analyzing experiments were used to identify whether this plant is a Cd-hyperaccumulator. When grown on soil spiked with Cd at the rate of 10 and 25 mg kg −1 in concentration gradient experiment, C. canadensis had both Cd enrichment factor (EF) and Cd translocation factor (TF) greater than 1, while the shoot biomass did not differ significantly as compared to the control. On the other hand, with Cd-spiking rates of 10 and 25 mg kg −1, the Cd concentration in the shoot did not exceed 100 mg kg −1, which is considered as the minimum shoot Cd concentration to qualify as a hyperaccumulator. In the sample-analysis experiments from a Pb–Zn mine area and wastewater irrigation region, C. canadensis also showed Cd-accumulator characteristics. Based on the results accomplished, we propose C. canadensis as a Cd-accumulator.