Background Levels Of Trace Elements Research Articles

Smelter-derived soil contamination in Luanshya, Zambia

Extensive mining and smelting contributed to the declining quality of Luanshya soils. The local smelter was the epicenter of contamination as shown by a spatial distribution analysis. Closeby soil profiles smelter exhibit extremely high Cu concentrations (up to 46,000 mg kg−1 Cu) relative to deeper layers where only background levels of trace elements were observed. A remote profile did not exhibit significant contamination.Lead isotopic ratios revealed that Pb contamination in the Luanshya soils was not smelter-derived. It was shown in this way that the historical usage of leaded gasoline was the main source of this metal. Although the Luanshya smelter also produced Co, this metal was not an important contaminant.Copper leaching was a concern in Luanshya. Upwards of 52 % of Cu was extractable in the exchangeable step of a sequential extraction procedure (SEP), but only for samples where Cu concentrations were high, suggesting that Cu was released exclusively from anthropogenic particles. This was supported by the SEP results for similar depths at the remote soil, where only a small fraction of Cu was labile (5.6 %). Lead and Co were strongly bound in the soils throughout.The excess of Cu in the topsoils was mostly bound in smelter-derived particles. These appeared as spherical fast-cooled droplets composed mostly of sulfides, oxides, and glass. X-ray diffraction and electron probe microanalysis of those particles allowed for a phase classification. Compositions were regularly not stoichiometric so most particles were classified as intermediate solid solutions. However, molecular proportions often closely resembled those of bornite, chalcanthite, cuprospinel, covellite, delafossite, diginite, or hydrous ferric oxides. Concentrations of Cu were often 100 % near the center of the particles indicating an inefficient smelting process. Weathering to some degree was common, which in conjunction with the susceptibility of Cu leaching was highly alarming.

Background levels of DTPA-extractable trace elements in calcareous soils and prediction of trace element availability based on common soil properties

Background levels of trace elements (TEs) are a crucial reference to assess the effects of human activity on soils globally. Traditionally background levels based on total TEs have been determined. However, levels of available TEs, the quantity of TEs that affects soil organisms and plant growth, have much greater relevance for biogeochemical processes. Therefore, here we determined background levels of diethylenetriaminepentaacetic acid (DTPA)-extractable contents of nine TEs in 100 soil samples from a region in Western Iran dominated by calcareous soils that has experienced low levels of human activity. Background levels determined using the iterative 2-δ technique were as follows (with comparable results using the distribution function method): Mn 11.6, Fe 6.9, Pb 1.6, Cu 1.1, Ni 0.6, Zn 0.6, Co 0.4, Cd 0.3, and Cr 0.1 mg kg−1. We further assessed how much of the variance in percentage available of total TE levels (DTPA-extractable fractions) can be explained by common soil properties. Unsurprisingly, pH and calcium carbonate equivalency were crucial parameters and for example explained 34 % of Cr availability. Electric conductivity and clay/sand content were equally important and explained 28 % and 35 % of Cu and Ni availability, respectively. The factor that explained most of the variance across all TEs was the soil organic matter content (explained for example 41 % and 21 % of Mn and Zn availability). Interestingly, the DTPA-extractable fractions of Cu, Mn, and Ni increased 4-fold and Zn 2-fold with an increase in organic matter (OM) content from 0.1 to 2 % in such high-pH soils. Multiple linear regression modelling using common soil properties reliably predicted TE availability (R2 values for measured versus predicted availability 84–93 %). These findings could help understand and predict TE behavior in calcareous soils and guide management practices.

Comparative Assessment of the Quality of Aerosol Filters for the Analysis of Ambient Air Pollution

Introduction. Atmospheric aerosols contain many carcinogenic and toxic substances, a significant part of which is represented by heavy metals. Traditionally, metal analysis is preceded by air sampling on AFA-HA-20 filters; yet, the lack of regulations on permitted background levels of trace elements in the filter material may limit reliability of measurements. Selection of filters with similar technological parameters can be a way to improve analytical accuracy. Objective: To determine contamination of different types of filters and to establish its effect on the results of spectral analysis of airborne metal concentrations in a large industrial city. Materials and methods: We analyzed unexposed AFA-HA-20 filters and Merck Millipore MF filters (n = 30 each) for the content of 13 heavy metals identified as priority pollutants within the Federal Clean Air Project. To assess the effect of filter contamination on the analytical error, air sampling was performed by exposing Merck Millipore MF filters at mobile monitoring stations in the city of Lipetsk. The filters were then analyzed by inductively coupled plasma mass spectrometry with prior microwave mineralization. Results: Our findings confirm the repeatedly obtained data on metal contents in null AFA-HA-20 filters and indicate significantly lower levels of contamination of unexposed Millipore MF filters made of mixed cellulose ethers. Conclusions: The risk of obtaining false positive and false negative results depends on the level and variability of the content of a particular trace metal in the filter. The AFA-HA-20 type of filters traditionally used for ambient air sampling may itself confound measurement result.

Mass balance of nine trace elements in two karst catchments in southwest China

High geological background levels of trace elements (TEs) and high population density in the karst areas of southwest China have imposed environmental pressure on the fragile ecosystems in this region. Understanding the mass budget of TEs, especially the toxic ones, is of great importance to sustain future developments. This study investigates the mass balance and fate of nine TEs (cadmium, arsenic, lead, chromium, copper, nickel, zinc, thallium, and antimony) in two karst catchments (Huilong and Chenqi) in southwest China through estimation of their mass budgets in throughfall, open field precipitation, total suspended particulate matter (TSP), litterfall, fertilization, harvested crops, surface runoff, and underground runoff. The estimated net fluxes are positive, indicating a source region, for four elements (Cu, Cr, Ni, and Tl) and negative, indicating a sink region, for five elements (As, Cd, Pb, Sb, and Zn) in both catchments. The net fluxes for the nine elements in Chenqi catchment are within a relatively small range (2.6, 2.0, 1.6, 0.6, −0.05, −0.5, −0.5, −2.9, and −3.3 mg m−2 yr−1 for Cu, Ni, Cr, Tl, Cd, Zn, Sb, Pb, and As, respectively), but in Huilong catchment in quite a large range (15.5, 6.0, 1.0, 0.8, −0.3, −0.9, −4.5, −7.5, and −8.7 mg m−2 yr−1 for Tl, Cr, Ni, Cu, Cd, Sb, As, Pb, and Zn, respectively). Rainfall (12.3%–66.2%) and litterfall (18.4%–81.3%) are the major input flux pathways, while crops harvest (16%–99%) is the major output flux pathway for the TEs in both catchments, indicating that the fate of TEs is shaped by both natural factors such as precipitation and litterfall and human activities such as fertilization and crop harvesting in these forestland-farmland compound karst catchments. Results from this study suggest that restoring forests from low-yield sloping farmlands will be useful for controlling TEs pollution in these fragile karst regions with high geological background TEs.

Background levels of trace elements in brown and red seaweeds from Trindade, a remote island in South Atlantic Ocean

Trace elements in organisms are normally higher in well-developed coastal areas than on oceanic islands. Few studies have used seaweeds as their sentinels on islands. This study established background levels of trace elements (As, Cd, Pb, Zn, Cu and Hg) for four seaweed species (Dictyopteris delicatula and Canistrocarpus cervicornis, brown algae; Ceratodictyon variabile and Palisada perforata, red algae) from Trindade, an oceanic Brazilian island, and verified potential differences associated to distinct environmental conditions. Spatial differences were not detected for As, Hg and Cd in samples, although the highest concentrations of these elements were observed in brown seaweeds. The highest Zn, Pb and Cu concentrations in seaweeds from the only inhabited beach may be a signal of the onset of human footprints on this still pristine, remote island. By comparison with background described in the literature, concentrations of trace elements in seaweeds were low, thus, allowing them to be considered reference levels.

Quality reference values of trace elements in Brazilian organosols

Determination of the natural background levels of trace elements in organosols and the proposal of quality reference values (QRVs) for these elements are essential for monitoring these soils because they are fragile and subject to change more intensely and rapidly than other soil classes. Given the above information, the objectives of this study were to determine the QRVs of trace elements for organosols and to correlate some soil properties with the occurrence of these elements. Forty organic soil horizon samples from different regions of Brazil were selected to determine the pseudo-total content of trace elements. The samples were separated into three groups according to a cluster analysis. The soil variable Fe and C contents had the strongest influence on the trace element contents in the organosols and were therefore used in the group classification functions. QRVs were proposed according to the 75th percentiles of the groups. The classification functions are a suitable tool for the allocation of new samples into previously established groups and may potentially be used to estimate the degree of organosol degradation.

Background levels of trace elements and soil geochemistry at regional level in NE Italy

Trace elements of both lithogenic and anthropogenic origin occur in soils distributed in various solid state forms, in the organic fraction and in the soil solution, and their fate in the environment depends upon several factors. The distribution patterns of element concentration are primarily influenced by the lithology of parent material, and secondly by the soil forming processes, that modify the basic geochemical composition and redistribute the content of metals within the soil profile. Alteration processes may lead to the release of potentially toxic elements, particularly heavy metals, into the environment. In this study, our objectives were to evaluate the background level and the concentration range of heavy metals in soils of a famous environmental scenery in northern Italy, to ascertain metal distribution and to identify possible contamination of some sites, and the related environmental hazard, with special reference to the pollution of the Dolomites area, which is a unique and delicate ecosystem. A regional soil survey was carried out in recent years in forested areas of the Trentino Region, in northern Italy. The territory investigated extends over approximately 400,000 ha (70% of the whole region), mostly in mountain areas. Approximately 460 soil samples from more than 120 representative soil profiles were collected and analysed for routine analyses and total Cu, Ni, Pb, Cd, Zn, Cr, Fe, Mn contents. Soils were grouped into 5 groups according to their pedogenetic characteristics. Most soil horizons (260) have acid reaction (mean pH = 6.1), though many are developed from calcareous rocks. Soil texture varies from sandy loam to silty loam. Cation exchange capacity varies consistently with the nature of parent material, as well as base saturation. The organic matter content is generally high at surface, and decreases with depth, the richest horizons (up to 11%) being those from calcareous materials. Background levels of trace elements in the soils investigated are consistent with currently recorded trace element concentration of soils from Western Europe. A geological matrix effect may be accounted for metal release by parent material weathering. Therefore, no contamination is recorded in the whole Trentino region. Nevertheless, metal accumulation in surface horizons at some sites may be ascribed to atmospheric input from local agricultural or industrial activities. Statistical analysis of geochemical data enhanced identification of pedogenetic processes responsible for the formation of soil groups with different weathering stages, and proved a useful tool to outline pedogenetic trends.

Soil contamination of heavy metals in the Katedan Industrial Development Area, Hyderabad, India

Studies on quantitative soil contamination due to heavy metals were carried out in Katedan Industrial Development Area (KIDA), south of Hyderabad, Andhra Pradesh, India under the Indo-Norwegian Institutional Cooperation Programme. The study area falls under a semi-arid type of climate and consists of granites and pegmatite of igneous origin belonging to the Archaean age. There are about 300 industries dealing with dyeing, edible oil production, battery manufacturing, metal plating, chemicals, etc. Most of the industries discharge their untreated effluents either on open land or into ditches. Solid waste from industries is randomly dumped along roads and open grounds. Soil samples were collected throughout the industrial area and from downstream residential areas and were analysed by X-ray Fluorescence Spectrometer for fourteen trace metals and ten major oxides. The analytical data shows very high concentrations of lead, chromium, nickel, zinc, arsenic and cadmium through out the industrial area. The random dumping of hazardous waste in the industrial area could be the main cause of the soil contamination spreading by rainwater and wind. In the residential areas the local dumping is expected to be the main source as it is difficult to foresee that rain and wind can transport the contaminants from the industrial area. If emission to air by the smokestacks is significant, this may contribute to considerable spreading of contaminants like As, Cd and Pb throughout the area. A comparison of the results with the Canadian Soil Quality Guidelines (SQGL) show that most of the industrial area is heavily contaminated by As, Pb and Zn and local areas by Cr, Cu and Ni. The residential area is also contaminated by As and some small areas by Cr, Cu, Pb and Zn. The Cd contamination is detected over large area but it is not exceeding the SQGL value. Natural background values of As and Cr exceed the SQGL values and contribute significantly to the contamination in the residential area. However, the availability is considerably less than anthropogenic contaminants and must therefore be assessed differently. The pre- and post-monsoon sampling over two hydrological cycles in 2002 and 2003 indicate that the As, Cd and Pb contaminants are more mobile and may expect to reach the groundwater. The other contaminants seem to be much more stable. The contamination is especially serious in the industrial area as it is housing a large permanent residing population. The study not only aims at determining the natural background levels of trace elements as a guide for future pollution monitoring but also focuses on the pollution vulnerability of the watershed. A plan of action for remediation is recommended.

Solid/liquid partition coefficients to model trace element critical loads for agricultural soils in Canada

Canadian consumers are demanding a sustainable agricultural industry as well as products delivered under Best Management Practices (BMPs). Trace element accumulation in soils may influence crop productivity, food quality and ecosystem and human health. Canada’s feed and foodstuff export industry has already faced cases of penalties for high trace element content [cadmium (Cd) in durum wheat]. Thus, it is imperative to be able to estimate the accumulation and potential short- and long-term impacts of trace elements in soil. A national-level Trace Element Indicator (TEI) based on present loadings of trace elements to agricultural land is in progress. An Expert Panel including Canadian, American and Australian experts guided the assembly of a proposed methodology for this TEI. The proposed TEI, described briefly here, is a critical load approach with a single expression of the risk of impact from single or multiple trace elements from multiple sources (manures, biosolids, effluents and fertilizers and natural processes), invoked in a stochastic manner. Two key data requirements are the current background levels of trace elements in soil, and the leachability of these trace elements. A survey of total and soluble concentrations of 54 elements in up to 112 soils was completed. Although preliminary in scope, these represent key soil series in Canada. From this, a database of the solid/liquid partition coefficient, Kd, was computed. These Kd values will be used to characterize the leachability of the trace elements. Key words: Cadmium, copper, zinc, lead, nickel, uranium, metals, Kd, distribution coefficient

Trace Element Concentrations of Three Soils in Central Appalachia

Trace Element Concentrations of Three Soils in Central Appalachia

Trace element hydrochemical assessment of the Calabar Coastal Plain Aquifer, southeastern Nigeria using statistical methods

Groundwater samples from 33 locations within the Coastal Plain Sands aquifer of Calabar (Nigeria) were collected and analysed for 43 trace elements by means of ICP-MS. The aim of this study is to determine the natural background levels of trace elements as a guide for future pollution monitoring of the aquifer. Secondly, this article focuses on the pollution vulnerability of the coastal plain sand aquifer. Statistical methods have been used to determine the source(s) of these elements. Results show that the area is characterised by four types of groundwater, including: Na-HCO3, Na-HCO3-Cl, Na-Cl and Ca-Na-HCO3-Cl. Secondly, all the elements considered are below normal averages. In addition, the Spearman correlation shows significant correlation especially among the lanthanide group of elements (p<0.0001). Factors analyses indicate mainly two groups of elements. The first group being due to the natural geochemical process (weathering/leaching of the basement lithology; characteristics of the elements) and the second is due to tidal flushing of the estuary. This indicates that the source of the trace element in the aquifer is due to a geogenic process and not anthropogenic. Thus, the present data set will serve as a reference source for pollution monitoring in the area.

Natural background levels of trace elements in wild plants: Variation and distribution in plant species

The natural levels of trace elements in wild plants of Japan were investigated. Wild plant shoots were collected at 16 sites from central to eastern Japan. The concentrations of various trace elements, namely, Be, Cu, Zn, Mo, Cd, Sb, Cs, Ba, La, Tl, Pb, Bi, in the 410 samples of 209 species were simultaneously analyzed by inductively coupled plasma mass spectroscopy. Geometric means were calculated with the data arranged according to plant species, some basic statistical parameters were calculated. Distribution of all the elements except La showed significant logarithmic normal pattern. The average concentrations of Sb, Cs, Ba, La, Pb, Bi in Pterophyta were higher than those in Anthophyta. The concentrations of Be, Cu, Ba, La, Pb were higher in Dicotyledonopsida than in Monocotyledonopsida and the reverse was true for Mo concentrations. Cu, Cd, Cs concentrations were higher in Sympetalidae than Archichlamiidae. Concerning plant families, Moraceae and Cyperaceae contained more Mo, Compositae, Polygonaceae, Liliaceae more Cd, Saxifragaceae more Cs, Polygonaceae more TI, the families belonging to Pterophyta showed higher Cd, Sb, La, Pb, Bi concentrations.

Natural background levels of trace elements in wild plants

Natural background levels of trace elements in wild plants were investigated. Firstly, the validity of the analytical methods using inductively-coupled plasma mass spectroscopy after wet digestion with HNO3 and HF was confirmed. Measurement results for standard plant material were almost the same as the certified values of Cu, Zn, Mo, Cd, Sb, and Pb. Additionally, other 6 elements, Be, Cs, La, Ba, n, and Bi were also analyzed simultaneously. Secondly, 87 plant species were collected from our Institute, and the basic statistical parameters of the element concentrations were calculated. Although distribution of the concentrations of Cu, Zn, Mo, Ca, Sb, and Pb displayed as logarithms was considered to be more symmetrical than that of normal data, only distribution of Cu and Cd fitted to a normal curve by chi-square test. Variance of element concentration was larger among species than within a species. Thirdly, plants and soils from 16 sites located in the central and eastern parts of Japan were collected. Median values of elemental concentrations in wild plants were used as representative values of a site, and median values among sites were 7.17,28.2, 0.367,0.150,0.031,0.701,0.009,0.043,32.4,0.125, 0.010, and 0.006 for Cu, Zn, Mo, Cd, Sb, Pb, Be, Cs, Ba, La, Tl, and Bi, respectively. The results for Cu, Zn, Mo, Pb, Be, La, and Bi were similar to the element concentrations for "Reference Plant," cited from a study by Markert (Markert, B. 1992: Multi-element analysis in plant materials. Analytical tools and biological questions. In Biogeochemistry of Trace Metals, Ed. D.C. Adriano, p. 401–428, Lewis Publishers, Boca Raton). The level of Cd was slightly higher and the levels of Sb, Cs, and Tl slightly lower than those of the “Reference Plant.” Our results for Be were 10-times as high as that for the “Reference Plant,” but very close to the concentrations reported by other researchers in Japan. Finally, to investigate the relationship of trace element concentrations between plants and soils, element concentrations in soils were analyzed after extraction with HF and HNO3 A high correlation was found in the case of Tl, but not for the other elements.

河川水・雨のウラン，トリウム，ランタノイドなど微量元素のバックグラウンド調査

河川水・雨のウラン，トリウム，ランタノイドなど微量元素のバックグラウンド調査

Trace and rare earth element content of white clay soils of the Three River Plain, Heilongjiang Province, P.R. China

Three representative pedons of white clay soils in the Three River Plain, Heilongjiang Province, P.R. China were sampled to establish background levels of trace elements and rare earth elements (REE) and to evaluate pedogenic redistribution of these elements. Trace elements and REE in soil samples and clay separates were measured by instrumental neutron activation analysis. New information was obtained for the background levels and pedogenic behavior of 20 trace elements and 10 REE. Cl, Br, I and Hg were enriched in the Ah horizon. Elements having an adsorption affinity for Mn and Fe oxyhydroxides (As, Co and Mn) were concentrated in the E horizon. Elements associated with clay minerals (Cr, Rb, V and Zn) were elevated in soil samples from the illuvial horizon, while elements present in resistant minerals (Sr, Ti, Hf and Zr) had relatively uniform profile distributions. Possible chemical causes of the trace element redistribution and partitioning are also discussed in the paper. REE were enriched in clay fractions compared to whole soil. Ce positive anomalies seen in normalized curves of REE for the E horizon were attributed to precipitation and accumulation of the element in pedogenic Fe-Mn nodules. The Gd break, even-odd and tetrad effects were present in normalized curves, which indicates fractionation of REE during weathering. The high ratio of light REE (sum La) to heavy REE (sum Lu) for the soil can be attributed to a warm, humid geochemical weathering environment in the past.

Background levels of microelements in soils of Italy

A systematic survey on the distribution of geochemically and texicologically relevant trace elements in the soils of Italy was carried out on 32 soil profiles, developed in different environmental and pedological conditions. The aim of this study was to collect basic information on the background levels of trace elements, their geochemical behaviour and the relationships between weathering and pedogenetic processes. The statistically processed analytical results led to the following conclusions: (i) Trace element distribution in the profiles studied is consistent with pedochemical behaviour and rock lithology. A comparison with the world soil means shows that there are no significant differences, except for those elements largely utilised in agriculture (Cu, Zn) or, because of pollution, (Pd, Cd), or natural accumulation (Ni, Cr); (ii) data processing by cluster analysis shows marked correlations between some elements, for example, Al-V, Ni-Cr, Mn-Co. Groups of geochemically homogeneous samples, which correspond to the great soil families characteristic of each pedological landscape, are also indicated; (iii) evidence of soil contamination is provided by the high levels of some elements, especially in the A horizon. Cu and Zn seem to be concentrated in the Ap horizon of cultivated soils, while Pd and Cd may be derived from the atmosphere.