Enrichment Of Zn Research Articles

Late Cretaceous black shales from the Tuscan Sedimentary Succession (northern Tuscany, Italy): geochemistry and ore mineralogy

We report on the first geochemical and mineralogical study of the Late Cretaceous black shales and black phyllites occurring within the basal portion of the “Scaglia toscana” and “Scisti sericitici” formations, respectively (Northern Apennines, northern Tuscany, Italy). The black shales occurring within the “Scaglia toscana” Formation are interbedded with red and greenish shales and form cm-thick layers; in some localities they are characterized by the occurrence of cm- sized pyrite nodules. Black phyllites and meta-cherts in the “Scisti sericitici” Formation are associated with Cu ores and with a small pyrite-molybdenite mineralization. These rocks are made of variable amounts of quartz, “chlorite”, illite/muscovite, pyrite ± calcite ± albite plus accessory amounts of baryte, apatite, sulfides and sulfosalts. In addition, they contain abundant carbonaceous matter (2-12 wt% total organic carbon). Whole-rock analyses by ICP-MS reveal a marked enrichment of Cd, Ag, Zn, Sb, Cu, Mo, V, Pb, and Tl with respect to the average marine shale and to the more typical shales of the “Scaglia toscana” fm. The distribution of these elements in the studied samples is compatible with a strongly anoxic and euxinic depositional environment. The hyper-enrichment of Cd, Ag, Zn, Sb and Cu strongly suggests that besides from seawater these elements were extracted from additional sources, most likely hydrothermal vents.

The effectiveness of foliar applications of different zinc source and urea to increase grain zinc of wheat grown under reduced soil nitrogen supply

Nitrogen is important for the enrichment of grain Zn when Zn is foliarly applied. However, decreasing soil N input has become a major issue for environmental protection. A 2-yr field experiment was conducted to evaluate the effectiveness of spraying different Zn sources [ZnSO4 or Zn(Gly)2] combined with or without urea on grain Zn concentration and bioavailability under reduced soil N rates, both in single wheat plantation and winter wheat-summer maize rotation. Results showed that foliar application of Zn(Gly)2 significantly increased grain Zn concentration by 88% under wheat-summer maize rotation and 150% under single wheat plantation. The effectiveness of foliar ZnSO4 application in increasing grain Zn was similar with that of Zn(Gly)2. Adding urea to foliar ZnSO4 or Zn(Gly)2 further increased grain Zn concentration under reduced soil N rates. Grain Zn biavailability increased with the reduction of soil N rates, but decreased after application of foliar Zn fertilizers. Foliar fertilization significantly increased protein, Fe, and Mn concentrations in grain, and the magnitudes of these increases were greater when Zn(Gly) 2 alone or ZnSO 4 plus urea were applied. Simultaneous foliar application of ZnSO4 and urea slightly increased farmer’s net income. These results suggest that foliar application of ZnSO 4 plus urea can be used as efficient and economical fertilization strategies to increase Zn concentration and bioavailability in wheat grain under reduced soil N supply, and consequently minimize Zn deficiency in humans.

A combined multivariate approach analyzing geochemical data for knowledge discovery: The Vazante – Paracatu Zinc District, Minas Gerais, Brazil

The Vazante Group comprises a Proterozoic sequence of carbonate and siliciclastic rocks located in Minas Gerais, Brazil. It is the host of the Vazante-Paracatu Zinc District, including world-class hypogene zinc silicate deposits, in the southern part, and several Pb – Zn sulfide deposits in the northern part, all hosted in dolomitic rocks. A recent study revealed the occurrence of base metal sulfide mineralization that formed prior to the Brasiliano orogenic event in the siliciclastic rocks (Serra do Garrote Formation) that underlie these dolomite-hosted silicates and sulfide deposits. These siliciclastic rocks were considered as potential sources of elements for the hydrothermal fluids that formed the dolomite-hosted deposits, however there was little evidence of depletion of the source rocks during the orogenic event. In this paper, Random Forest is used in unsupervised mode along with t-distributed Stochastic Neighbor Embedding (t-SNE) and principal component analysis (PCA) over a lithogeochemical dataset of samples of the Serra do Garrote siliciclastic rocks collected throughout the basin to provide insights about processes related to the mineralizing system at the Vazante-Paracatu District.Multivariate analysis reveals that the Serra do Garrote Formation geochemical signature typical of pre-orogenic mineralization. This is characterized by PC1+ with association of Zn, Cd, Cu, Hg, In, V ± Sb, Se, Mo, Re, which corresponds to nearly 60% of the variance in the data. This suggest that these elements are related to a widespread and/or, long-living hydrothermal activity without an efficient mechanism to focus the metal-bearing fluids, causing basin-scale sub-economical Zn and related metal enrichment. Furthermore, PC2 and PC6 distinguish the zones with signatures interpreted to be related to depletion. PC2+ separates Cd-poor sphalerite, which is typical of the generation of sphalerite that occur in zones with textural evidence of remobilization. PC6+ with association of As, organic carbon and S, identified the zones where sphalerite was leached from the pyrite-rich layers. Areas with multivariate signatures of both pre-orogenic enrichment and syn-orogenic depletion in the source siliciclastic rocks include the Vazante-North Extension and Varginha zinc silicate deposits/occurrence, Ambrósia silicate zinc deposit and the Engenho Velho prospect. Preliminary exploration in this prospect revealed hydrothermal alteration typical of the zinc silicate deposits. This study is pioneering in applying these numerical models in possible source rocks to assist in identifying targets for exploration in basins.

Seasonal Chemical Composition Characteristics and Source Apportionment of PM2.5 in Zhengzhou

The aim of this study was to fully understand the pollution characteristics and sources of PM2.5 in Zhengzhou, and to investigate the differences in four seasons and between urban and suburban areas. At the Zhengzhou environmental monitoring center (urban areas) and Zhengzhou University (suburban areas), 1284 environmental PM2.5 samples were collected in the four seasons of 2018. The concentrations of nine kinds of inorganic water-soluble ions, organic carbon, elemental carbon and 27 kinds of elements, were measured by ion chromatography, carbon analyzer, and X-ray fluorescence spectrometry, respectively. Enrichment factors (EF), index of geoaccumulation (Igeo), potential ecological risk index (RI), chemical mass balance model (CMB), backward trajectory, and potential source contribution function were the methods used to study the chemical component characteristics and source differences of PM2.5 in different seasons in the urban and suburban areas of Zhengzhou. The results showed that the annual average PM2.5 concentration at the Zhengzhou environmental monitoring center and Zhengzhou University sites reached (59.7±24.0) μg·m-3 and (74.7±13.5) μg·m-3, respectively. The PM2.5 concentration at the suburban point was higher than at the urban point with the exception of winter, and the seasonal mean concentration decreased in the order of winter > autumn > spring > summer. Compared with the urban areas, the suburban areas were more affected by crustal substances in spring, and the concentrations of all components were higher in summer and autumn than the urban areas. Nevertheless, urban areas were more affected by coal burning sources and motor vehicle sources in winter. The component analysis results showed that the influences of soil dust and building dust were greater in the suburbs in spring than in the urban areas. In autumn, the suburbs were more affected by biomass sources than the urban areas, while the urban areas were more affected by building dust than were the suburbs. The concentrations of Cu, As, Zn, Pb, and Sb were strongly influenced by anthropogenic sources, and the enrichments of Zn, Cu, As, and Pb in urban areas were greater than in the suburbs. In addition, Zn, Cu, As, and Pb exhibited potential ecological risks. The outcomes of the CMB model showed that dust sources, secondary sulfate, secondary nitrate, and coal burning sources contributed significantly to PM2.5 concentrations in spring, summer, autumn and winter, respectively. The contributions of secondary pollution sources (secondary organic aerosol, secondary sulfate, and secondary nitrate) and motor vehicle sources to urban areas were higher than to suburban areas, and the influences of biomass sources in autumn and winter were significantly higher than in spring and summer and urban areas. The backward trajectory results indicated that the local PM2.5 concentration was affected by distant transmission from the northwest except in summer, was affected by neighboring provinces in the east in four seasons, and was affected by transmission from the south, with the exception of winter. Furthermore, the consequences of potential sources demonstrated that the local PM2.5 concentration was mainly affected by the potential areas in Henan province and its boundary with neighboring provinces.

Geogenic pollution, fractionation and potential risks of Cd and Zn in soils from a mountainous region underlain by black shale

This study investigated the pollution, fractionation and potential risks of heavy metals in soils from a mountainous area with black shale outcropping, with emphasis on Cd and Zn. Elevated concentrations of heavy metals in black shales reflected high geochemical baseline in the study area. Metals released from oxidative weathering were redistributed and retained during pedogenic processes, leading to enrichment of Cd, Cu, Cr, Ni, V and Zn in soils. As a highly concerned metal pollutant, the content of Cd in all collected samples (N = 112, Cd: 0.44–16.1 mg/kg) exceeded the risk screening value for Chinese agricultural land. Metals in local soils were retained through adsorption onto soil constituents clay minerals and FeMn oxides and/or precipitation within secondary minerals. Based on sequential extraction, Cd and Zn fractionated in soils, with Cd mainly occurring in the mobile fraction (47.9% to 78.7%) as adsorbed, FeMn oxides and carbonate associated phases, whereas residual fraction (67.1%) dominated for Zn, followed by FeMn oxides coagulation (17.9%). Metals in residual soils from slopping location were highly related to metals in the parent rocks distributed more heterogeneously than metals in alluvial soils from flat location. High levels of heavy metal pollution in soils posed potential risks to the local eco-environmental systems and community, and Cd was highly concerned due to its high mobility. Cultivation in alluvial soils from valleys poses less risk than in residual soils, but appropriate approaches to reduce the risk in local soils is still necessary. The findings from this study provide basic knowledge and insight for risk control and targeted management of soils with geogenic heavy metal pollution in black shale outcropped mountainous areas.

Formation of highly Zn-enriched sulfide scale at a deep-sea artificial hydrothermal vent, Iheya-North Knoll, Okinawa Trough

Artificial hydrothermal vents, created by boreholes that discharge hydrothermal fluids and useful for observing secular changes in mineral precipitates and the chemical compositions of hydrothermal fluids, are periodically cleaned of scale deposits. Here, we report petrographic and geochemical features of hydrothermal scale with a concentric structure and extreme enrichment in Zn, recovered as an intact plug from an artificial hydrothermal vent pipe in the Okinawa Trough. The scale consists of sphalerite with accessory galena and chalcopyrite, and minor cotunnite (PbCl2), barite, an unidentified Zn sulfate, and Bi-rich minerals. It comprises at least five concentric layers alternating between thin, reddish-brown porous layers composed of relatively Fe-rich sphalerite accompanied by galena and chalcopyrite, and coarse-grained, dark gray layers dominated by relatively Fe-poor sphalerite. Cotunnite occurs only in the innermost reddish-brown layer, and barite occurs only in the uppermost and innermost layers. The scale is composed of > 50 wt% Zn, several wt% Fe and Pb, and < 1 wt% Cu, Mn, and Cd, a composition consistent with the solubility of Zn and Cu in a hydrothermal fluid at 304–311 °C and pH 4.7–5.0. We suggest that the concentric layers are related to periodic scale removal operations through which (1) mostly clogged pipe conditions and weak hydrothermal discharge alternate with (2) fully open pipe conditions and vigorous hydrothermal discharge, thus affecting sulfur fugacity and [Cl−] and [SO42−] activities in the hydrothermal fluid and leading to the formation of concentric layers of precipitated minerals.

Urban street dust in the Middle East oldest oil refinery zone: Oxidative potential, source apportionment، and health risk assessment of potentially toxic elements

The current study is the intented to investigate the intensity of pollution, source characterization, oxidative potential, and human health risks of fourteen potentially toxic elements in the street dust of the Middle East oldest oil refinery zone. Thirty five street dust samples were collected from various regions in Abadan and Khorramshahr cities. The mean concentration of As, Mo, Cu, Pb, Hg, Zn, Cd, and Sb in Abadan street dust were 5.55, 3.39, 83.68, 49.82, 4493.54, 281.24, 1.15,and 1.17, while in Khorramshahr As, Mo, Cu, Pb, Hg, Zn, Cd, and Sb were.14, 2.58, 74.35, 56.50, 0.74, 214.26, 0.62, and 1.18, respectively. The concentration of these elements in both cities is higher than the local background values. Potential ecological risk index and pollution load index at all stations of both cities are greater than 1, indicating a high pollution load in the study area. Calculated enrichment factor showed high enrichment of Hg, Sb, Cd, Mo, Cu, Pb, and Zn in both areas. Of particular concern is the enrichment factor for mercury which proved to be 3370.54 ppb in the vicinity of the petrochemical unit in Abadan city (EF > 40). The results of positive matrix factorization receptor model together with geochemical maps and multivariate statistics indicated that industrial activities (especially petrochemical industries) are responsible for Hg, Cu, and Zn pollution, while exhaust emissions are responsible for Mo, Pb, Cd, and Sb, and natural sources for Al, Cr, Mn, Fe, Co, and Ni. The percentage of OPAA in the region ranged from 15.1 to 26.4 and OPGSH ranged from 9.5 to 24.4. The percentage of OPTOTAL/μg (OPAA/μg + OPGSH/μg) values varied between 0.6 and 1. The health risk evaluation models indicated that specific attention should be paid to Hg, Cd, Pb, and Zn and that the higher oxidative potential of street dust recovered from polluted locations is also a matter of concern in Abadan and Khorramshahr Cities.

Flood hazard assessment and characteristics of cement kiln dust in Ain Sukhna industrial area, north‐western part of the Gulf of Suez, Egypt

AbstractThis study investigated the geochemical and mineralogical characteristics combined with heavy elements concentrations of Cement kiln dust (CKD) in Ain Sukhna industrial area, North‐western part of the Gulf of Suez, Egypt and the influence of flash floods in its stability. Flooding severity is moderate with several water erosional processes. The CKD characterized by very poorly sorted/very fine‐sands to silt. CaO and SiO2 are major components with enrichment of chloride/sulfate ions. High enrichment of Sr, Zn, Pb, Cd, Sb, and Se are related to variations in shale/limestone feeds during cement formation. The threshold effect level exceeds the standard value for Cd, Pb, and Zn at S3 that indicates adverse biological effects. Sylvite, calcite, and halite minerals were dominated. Three main principal components recognized the shale, calcium/magnesium carbonate dissolution, and the scavenging effect of sulfate for heavy elements. Monitoring the CKD leachability and proper management plans are prerequisite for environmental protection in the future.

Geochemical behavior and remobilization potential of trace elements in surface sediments from the baixada santista industrial area, Southeastern Brazilian coast

A three-stage sequential extraction procedure optimized by the European Community Bureau of Reference (BCR) was applied to assess the geochemical behavior and environmental mobility of As, Cr, Cu, Ni, Pb and Zn in surface sediments from two ecosystems under different anthropogenic influences, the Estuarine Complex of Santos and Sao Vicente (ECSSV) upper estuary (high anthropogenic influence) and the Bertioga channel (low anthropogenic influence), both of which are located on the coast of Sao Paulo, Brazil. In general, the difference between the regions varied considerably for almost all these elements, and the values for the Bertioga channel were always lower than those found in the upper estuary. Among all the elements, Zn showed the greatest mobility, being present mainly in the acid-soluble fraction. Arsenic and Pb were associated with the reducible fraction, and Cu and Ni in the oxidizable fraction. Meanwhile, Cr was mainly found in the residual fraction. Although previous studies, regarding total concentrations suggest the probable enrichment of Cu, Pb and Zn in the surface sediments of the ECSSV, according to our results and the Risk Assessment Code (RAC) analysis, only Zn presented a high risk of bioavailability, and the modified Risk Assessment Code (mRAC) only showed six samples in the inner estuary with a medium risk of mobilization. Therefore, this study can serve as a management tool and optimize the monitoring efforts of chemical pollution in the region.

Synergistic improvement of soil organic carbon storage and wheat grain zinc bioavailability by straw return in combination with Zn application on the Loess Plateau of China

Organic amendment can increase soil zinc (Zn) availability and its uptake in cereals. Conversely, Zn transformation in soil may modify soil organic carbon (SOC) dynamics. To date, the effects of the simultaneous addition of organic material and Zn fertilizer on soil SOC storage and crop Zn enrichment have received little attention. Here, with a view to clarifying this problem, a 2-year wheat-based field study was conducted on the Loess Plateau in China with the following treatments: control, SR alone (SR7.5, 7.5 Mg·ha−1), ZF alone (ZF15, 15 kg Zn·ha−1), and SR plus ZF (ZF15SR7.5). The results indicate that loss of SOC after 2 years was 0.6 Mg·ha−1 in the control soil, and an input of 2.2 Mg C·ha−1·y−1 was needed to maintain the pre-experimental SOC stock. However, the increase in SOC storage after 2 years was 1.0 Mg·ha−1 in soil with SR7.5 and 2.6 Mg·ha−1 in soil with ZF15SR7.5, which accounted for 9.3% and 24% of residue-C input, respectively. On the other hand, the concentration of available Zn in soil with ZF15 was 3-fold higher than that in the control soil, but lower than that in soil with ZF15SR7.5 in both years. The Zn uptake by wheat and the grain Zn concentration also increased as the soil Zn availability increased, especially in the second year. Most importantly, in soil with ZF15SR7.5, the wheat grain Zn concentration reached 38 mg·kg−1 after 2 years, and the estimated dietary-absorbed Zn was 3.65 mg·d−1, which met the recommended Zn intake of 3 mg·d−1 for adults. Therefore, combining SR and ZF shows a promising synergistic effect for the enhancement of both SOC storage and wheat grain Zn bioavailability on China’s Loess Plateau and other drylands.

Formation and evolution of multistage ore-forming fluids in the Miocene Bangpu porphyry–skarn deposit, Southern Tibet: Insights from LA–ICP–MS trace elements of quartz and fluid inclusions

Abstract The large Bangpu Mo–Cu–Pb–Zn deposit, is a Mo-rich (~0.089%), Cu-poor (~0.32%) porphyry–skarn deposit located in the northeastern Gangdese porphyry copper belt (GPCB), Southern Tibet. In this study, LA–ICP–MS data for fluid inclusions and quartz formed during different stages of the mineralization are used to (1) constrain changes in fluid composition during mineralization; (2) infer the origin, transport pathways, and conditions of ore precipitation; and (3) explore the influence of magma chamber on fluid exsolution and shallow mineralization. The Cu content of the vapor-rich (VL) inclusions is higher than that of the halite-bearing (LVH) inclusions, while the Mo, Pb, and Zn contents of the VL and LVH inclusions are similar, indicating that Mo, Cu, Pb, and Zn had a common source, which is inferred to be the intermediate-level magma chamber. The metal contents of fluid inclusions in the early stage potassic alteration-related vein (A vein) and later stage sericitic alteration-related vein (B vein) are similar but variable, implying the intermediate-level magma chamber was too small to form a large stable fluid system. The enrichment of Mo, Pb, and Zn in the Bangpu deposit relative to other porphyry deposits in the GPCB is related to the participation of ancient crustal material. A comparison of our results with those from super-large porphyry Cu deposits elsewhere indicates that metal-rich fluids are not the sole factor to form ore deposits, and the variability of metal contents in the early exsolved fluids is a better predictor of mineralization potential than absolute metal concentrations.

Investigation of Zn- and Pb-rich deposits on water-wall tubes in three coal-fired boilers

In this study eight types of deposits were collected from the surface of water-wall tubes, in the lower and middle sections of three pulverized coal boilers. The chemical characterization of all deposits formed under reducing atmosphere was explored. Based on thermodynamic calculation of Pb-Zn-O-S system, the causing for Pb and Zn enrichment in deposits was analyzed, and then the deposition mechanism of Pb- or Zn-rich particles was clarified. The results show that, Fe, Zn and Pb sulfides are contained substantially in deposits and their enrichment has a sequence of time in the profile section of deposits. Pb element as PbS is enriched in the inner layer of deposits, due to the direct condensation of PbS(g) or and Pb(g). While the Zn enrichment in layered deposits falls behind Pb element. Zn element exists largely as the form of ZnS and ZnAl1.04S2.13 in the depositing layer, which is attributed to the heterogeneous condensation of Zn(g) rather than ZnS(g), the sulfidation reaction of Zn(g), and the subsequent thermophoresis deposition of fine particles. The mole ratio of S to Pb + Zn in deposits could be used for roughly and quickly evaluating the degree of sulfide corrosion.

Oral bioaccessibility of potentially toxic elements (PTEs) and related health risk in urban playground soil from a medieval bell metal industrial town Khagra, India.

In vitro oral bioaccessibility assay (simple bioaccessibility extraction test) was used to assess bioaccessible PTEs (As, Cd, Co, Cu, Fe, Mn, Ni, Pb, Sn, and Zn) in 16 playground soils of Khagra, which is a medieval bell metal industrial town at Murshidabad district, West Bengal, India. The aim was also to establish levels of potentially toxic elements (PTEs) in soil, their origin, and human health risk, particularly on children. The average pseudo-total PTEs content in playground soil samples was in the decreasing order of Fe (18,988mgkg-1) > Zn (1229mgkg-1) > Cu (999mgkg-1) > Mn (343mgkg-1) > Pb (181mgkg-1) > Sn (132mgkg-1) > Co (8.63mgkg-1) > As (5.21mgkg-1) > Cd (0.88mgkg-1). The pollution indices indicate significant enrichment of Cd, Cu, Pb, Zn, and Sn in the playground. The bioaccessible percentage of PTEs in the 16 playground soils ranged from 0 to 80.25%, where the range of percentage of bioaccessibility was 13.24-62.50, 0-61.46, 16.82-28.79, 5.05-73.06, 0.96-6.14, 2.28-38, and 0-80 for As, Cd, Co, Cu, Fe, Ni, and Zn, respectively. The order of percentage of bioaccessibility was As > Mn > Zn > Sn > Cu > Co > Pb > Cd > Ni > Fe. PCA extracted two major factors indicating the anthropogenic (Cd, Cu, Ni, Pb, Zn, and Sn) and geogenic (Co, Fe, and Mn) source. Stepwise multiple regression analysis exhibited that the oral bioaccessibility of PTEs did not correlate with physicochemical parameters like pH, EC. In contrast, Sn had a significant correlation with that of organic matter. The health risk for pseudo-total as well as bioavailable fraction in playground soil depicted that children were more vulnerable to ingestion of soil contaminated with PTEs, particularly for Cu and Pb. A risk management plan with the bioaccessible data involving detailed site-specific exposure factors to indicate the importance of the study in terms of child health safety is required.

Apportionment of some chemical elements in soils around the coal mining area in northern Bangladesh and associated health risk assessment

In this work, fifteen chemical elements viz., Pb, Cd, Cr, As, Ag, Mn, Fe, Co, Ni, Cu, Zn, Na, K, Ca, and Mg were estimated in the coal mine-impacted soil samples sourced from Barapukuria coal mine area of Bangladesh using atomic absorption spectrometer and flame photometer for assessing their contamination levels with an implication to human health and environment. The level of considered elements was found to be lower compared to their corresponding world normal limit, except for Zn. Physicochemical properties of soils such as pH, oxidation-reduction potential, and electrical conductivity, as measured using a multiparameter meter in aqueous solution, indicated the acidic nature of soils with the presence of considerable oxidizing and ionic substances. Principal component, cluster, and correlation analyses ascertained the probabilistic anthropogenic sources of elemental contaminations and significant inter-parameter associations. These analyses suggest that Zn, Cu, Ni, Co, Cd, Mn, and As in soil originated from anthropogenic activities, particularly from the adjacent coal mining operations, indicating a common source of origin. Enrichment factor (EF), geo-accumulation index (Igeo), contamination factor (CF), pollution load index (PLI), ecological risk factor (Er), potential ecological risk index (RI), and human health risk assessment of chemical elements were employed for evaluating the impact of potentially hazardous elements in soils on surrounding environment and local residents. EF values suggest a significant enrichment of Ag, As, Zn, Cd, Pb, Co, Ni, Mn, and Cu in soils having anthropogenic origin while K, Cr, Ca, Na, and Mg originated from geogenic sources. The Igeo and CF data indicate a considerable accumulation of Cd, As, Ag, and Zn in the soil. A moderate risk potential was manifested by the Er and RI indices posing a threat to the soil environment. The non-carcinogenic threat was observed mostly among the children cohort due to the preponderance of these elemental concentrations.

Multi-Stage Introduction of Precious and Critical Metals in Pyrite: A Case Study from the Konos Hill and Pagoni Rachi Porphyry/Epithermal Prospects, NE Greece

The Konos Hill and Pagoni Rachi porphyry-epithermal prospects in northeastern Greece are characterized by abundant pyrite that displays important textural and geochemical variations between the various ore stages. It is commonly fine-grained and anhedral in the porphyry-related mineralization (M- and D-type veins), while it forms idiomorphic, medium- to coarse-grained crystals in the late, epithermal style veins (E-type). Porphyry-style pyrite from both prospects is characterized by an enrichment in Co, Se, Cu, and minor Zn, and a depletion in other trace elements, like Bi, Mo, Ag, etc. Pyrite in epithermal-style mineralization is mostly characterized by the presence of As, Bi, Pb, Ni, and Se. Gold in pyrite from all mineralization stages occurs as a non-stoichiometric substituting element, and its abundance correlates with As content. Arsenic in pyrite from Konos Hill records an increase from the porphyry stage to the epithermal stage (along with gold); however, at Pagoni Rachi, the highest Au and As contents are recorded in D-type pyrite and in the epithermal stage. The composition of the studied pyrite marks changes in the physico-chemical conditions of the ore-forming fluids and generally follows the geochemical trends from other porphyry-epithermal systems elsewhere. However, a notable enrichment of Se in the porphyry-style pyrite here is a prominent feature compared to other deposits and can be considered as an exploration tool towards Au-enriched mineralized areas.

Depositional environment and metal distribution in mangrove sediments within middle region of tropical estuaries, Karnataka, west coast of India

Two mangrove sediment cores representing middle region of the Panchagangavali Estuary (one each at Chakra Estuary and Halady Estuary) were analysed for sedimentological and geochemical parameters. The data revealed prevalence of uniform violent hydrodynamic energy condition in the Chakra Estuary (core G3), whereas, varying and relatively calm hydrodynamic energy conditions in the Halady Estuary (core G4). All the studied metals (Al, Fe, Mn, Ni, Zn, Cu and Cr) were of mainly lithogenic origin in both the estuaries, except Co which may be derived from a different source. The Enrichment Factor (EF) indicated deficiency to minimal enrichment of Fe, Mn, Ni, Zn, Cu and Co whereas, Cr showed a moderate enrichment in sediments. However, metals Fe, Ni, Zn, Cr and Cu were relatively enriched in the top section 3 of Halady Estuary indicating their enhanced release in recent years possibly due to increased human activities and high rain fall in the catchment area.

Uptake of trace elements and isotope fractionation of Cu and Zn by birch (Betula pendula) growing on mineralized coal waste pile

Aims of the present study were to determine the extent of the uptake of selected trace elements by birch (Betula pendula Roth) growing on the partly burnt coal waste pile and to evaluate isotopic fractionation of copper (Cu) zinc (Zn). Substrates, birch sap and leaves were collected in the coal waste pile and in a reference area outside the waste pile. The concentration of trace elements in birch sap and leaves both in birch growing on the coal waste pile and at reference sites increase in the range of U, As, Se > Cd, Mo, Cu > Pb > Ba ≫ Zn. However, the uptake of elements by birch is restricted when concentration of metals in substrates are too high.Compared to the isotopic composition of Cu in waste substrates and soils (δ65Cu = – 0.93 to + 1.49‰), this element in sap and leaves (δ65Cu = – 0.58 to −1.64 and – 0.59 to – 2.35‰, respectively) is depleted in heavy isotope regardless of plant-available concentration of Cu in substrates. Compared to the isotopic composition of Zn in substrates (δ66Zn = – 0.20 to 1.43‰), its isotopic composition in sap and leaves (δ66Zn = – 0.85 to + 1.00 and – 0.21 to + 0.57‰, respectively) is depleted in the heavy isotope only when the plant-available concentration of Zn in the substrate and soil is high (>20 mg kg−1). At low plant-available concentration of Zn no isotopic fractionation or enrichment of Zn in the heavy isotope was recorded.

Fourteen years of compost application in a commercial nectarine orchard: effect on microelements and potential harmful elements in soil and plants

The objective of this experiment was to valuate, after 14 years, the impact of annual compost applications on micronutrient and potentially toxic trace elements on nectarine tree uptake and soil fertility. The study was performed in the Po valley, Italy, on the variety Stark RedGold (grafted on GF677). Since orchard planting, the following treatments were applied, in a randomized complete block design, with four replicates: 1. unfertilized control; 2. mineral fertilization (N was supplied as NO3NH4 at 70–130 kg ha−1 year−1); 3. compost at 5 t DW ha−1 year−1; 4. compost at 10 t DW ha−1 year−1. The actual rate of application was 12.5 (LOW) and 25 (HIGH) t ha−1, since compost was concentrated in the tree row. Compost was made from domestic organic wastes mixed with pruning material from urban ornamental trees and garden management and stabilized for 3 months.The supply of compost HIGH induced an enrichment of soil total Cu, Zn and Cd, and a decrease of Fe and Co concentration; with values always below the European threshold limits for heavy metals in the soil. In addition, compost (at both rates) increased availability (DTPA-extractable) of Fe, Mn and Zn, Cd, Ni, and Pb in the top soil (0–0.15 m).Total micronutrient and trace element tree content was not affected by fertilization treatments; however, the recycled fraction returned to the soil at the end of the season through abscised leaves and pruned wood of Cu, Fe, Mn and Zn was increased by mineral fertilization; Fe and Zn also by compost HIGH. Our data show that the introduction of compost at both 12.5 and 25 t ha−1 year−1 in the row did not increase the risk of pollution related to potentially toxic trace elements and at the same time increased the bioavailability of Fe, Mn and Zn.

Geographical information systems based ecological risk analysis of metal accumulation in sediments of İkizcetepeler Dam Lake (Turkey)

This study analyzed the spatial distribution, potential ecological risks and possible sources of metal concentrations, organic carbon, chlorophyll degradation products and CaCO3 content from surface sediment samples in İkizcetepeler Dam Lake using ecological-toxicological indices, multivariate statistical analysis, and geographical information systems (GIS) software. One core sample and 32 surface sediments were taken from the Dam Lake, while seven lithologic samples were taken from various points in the basin. To identify anthropogenic influences in the Dam Lake from the before dam was constructed period to the present day, the enrichment factor (EF), contamination factor (CF), geoaccumulation index (Igeo), toxic risk index (TRI) and pollution load index (PLI) indices were calculated based on lithologic background values. Modified ecological risk (mER) and modified potential ecological risk (mPER) were calculated separately according to core sample and lithologic background values. Therefore, ecological risk during Anthropocene was determined using core sample values. Results pointed to significant enrichment of Ni (6.93), moderate enrichment of As (3.88), Cr (2.86), Mn (2.54), Hg (2.34), and Cd (2.04) and low level enrichment of Pb (1.20), Cu (1.15), Zn (1.08), and Fe (0.80). Ecological risk was listed as Hg (94) > Cd (61) > As (38) > Ni (35) > Cu (5.98) > Cr (5.72) > Pb (5.68) > Zn (1.07) according to lithologic background values and as Hg (59) > Cd (29) > As (9) > Ni (8) > Cu (7) > Pb (5) > Cr (2.97) > Zn (1.42) according to core background values. A significant level of ecological risk was determined for Hg (94), medium level ecological risk for Cd (61), and close to moderate level ecological risk for As (38) and Ni (35). The risk was low for all the other metals. According to the core sample background values, ecological risk was at the lowest limit of the most significant level for Hg (81), moderate for Cd (50) and low for other metals. Overall, this indicates a low (123) and moderate (201) potential ecological risk in İkizcetepeler Dam Lake based on core and lithologic background values, respectively.

The influence of natural weathering on the behavior of heavy metals in small basaltic watersheds: A comparative study from different regions in China

This paper investigates the dynamics between basalt weathering and heavy metal accumulation through a comparative study of 37 small basaltic watersheds within different climate zones in the Yungui (the Pearl River Basin in southwest China), Xuyi (the Huaihe River Basin in east China) and Leiqiong regions (Hainan Island in south China). From a comprehensive sampling regime of stream water, riverbed sediments and bedrock, this study shows that the concentrations of heavy metals in river water are far below the national surface water quality standard and WHO quality standard for drinking water, indicating no significant ecological risk for water body in these basaltic areas. In contrast, the riverbed sediments exhibit varying degrees of heavy metal enrichment in the process of weathering from bedrock to sediments: without enrichment for Cr, Ni, Cu and Zn, but significant enrichment for Cd, As and Pb. Cd exhibits the largest ecological risk of all the heavy metals in the basaltic watersheds especially in the Yungui region, which can be mainly attributed to the high geological background values in this area. Comparative studies of some major basalt watersheds in the world show that temperature, runoff and elevation differences significantly affect the chemical weathering rates and thus the accumulation of heavy metals.