Trace elements contamination of agricultural soils affected by sulphide exploitation (Iberian Pyrite Belt,Sw Spain)

Agricultural soils of the Riotinto mining area (Iberian Pyrite Belt) have been studied to assess the degree of pollution by trace elements as a consequence of the extraction and treatment of sulphides. Fifteen soil samples were collected and analysed by ICP-OES and INAA for 51 elements. Chemical analyses showed an As–Cu–Pb–Zn association related with the mineralisation of the Iberian Pyrite Belt. Concentrations were 19–994 mg kg⁻¹ for As, 41–4,890 mg kg⁻¹ for Pb, 95–897 mg kg⁻¹ for Zn and of 27–1,160 mg kg⁻¹ for Cu. Most of the samples displayed concentrations of these elements higher than the 90th percentile of the corresponding geological dominium, which suggests an anthropogenic input besides the bedrock influence. Samples collected from sediments were more contaminated than leptosols because they were polluted by leachates or by mining spills coming from the waste rock piles. The weathering of the bedrock is responsible for high concentrations in Co, Cr and Ni, but an anthropogenic input, such as wind-blown dust, seems to be indicative of the high content of As, Cu, Pb and Zn in leptosols. The metal partitioning patterns show that most trace elements are associated with Fe amorphous oxy-hydroxides, or take part of the residual fraction. According to the results obtained, the following mobility sequence is proposed for major and minor elements: Mn, Pb, Cd, > Zn, Cu > Ni > As > Fe > Cr. The high mobility of Pb, Cu and Zn involve an environmental risk in this area, even in soils where the concentrations are not so high.     

Major and trace elements in plants and soils in Horton Plains National Park,Sri Lanka: an approach to explain forest die back

Forest die back has been observed from 1980s in the montane moist forest of Horton Plains in the Central Sri Lanka for which the aetiology appears to be uncertain. The concentration levels of Na, K, Ca, Mg, Fe, Mn, Cu, Ni, Zn and Pb in canopy leaves, bark and roots, which were collected from dying and healthy plants of three different endemic species, Calophyllum walkeri, Syzygium rotundifolium and Cinnamomum ovalifolium, from three different die back sites were studied. Soils underlying the plants were also analyzed for their extractable trace metals and total contents of major oxides. Analysis of dead and healthy plants does not show any remarkable differences in the concentrations of studied trace elements. The results show that there is a low status of pollution based on the concentrations of chemical elements of environmental concern. Extractable and total trace element analysis indicates a low content of Ca in soils due to high soil acidity that probably leads to Mg and Al toxicity to certain plants. Relatively high Al levels in the soil would affect the root system and hamper the uptake and transport of essential cations to the plant. It therefore seems that the forest declining appears to be a natural phenomenon, which occurs due to the imbalance of macro and micronutrients in the natural forest due to excessive weathering and the continuous leaching of essential elements.     

Transport and sediment–water partitioning of trace metals in acid mine drainage: an example from the abandoned Kwangyang Au–Ag mine area, South Korea

Transport and sediment–water partitioning of trace metals (Cr, Co, Fe, Pb, Cu, Ni, Zn, Cd) in acid mine drainage were studied in two creeks in the Kwangyang Au–Ag mine area, southern part of Korea. Chemical analysis of stream waters and the weak acid (0.1 N HCl) extraction, strong acid (HF–HNO₃–HClO₄) extraction, and sequential extraction of stream sediments were performed. Heavy metal pollution of sediments was higher in Chonam-ri creek than in Sagok-ri creek, because there is a larger source of base metal sulfides in the ores and waste dump upstream of Chonam-ri creek. The sediment–water distribution coefficients (K _d) for metals in both creeks were dependent on the water pH and decreased in the order Pb ≈ Al > Cu > Mn > Zn > Co > Ni ≈ Cd. K _d values for Al, Cu and Zn were very sensitive to changes in pH. The results of sequential extraction indicated that among non-residual fractions, Fe–Mn oxides are most important for retaining trace metals in the sediments. Therefore, the precipitation of Fe(–Mn) oxides due to pH increase in downstream sites plays an important role in regulating the concentrations of dissolved trace metals in both creeks. For Al, Co, Cu, Mn, Pb and Zn, the metal concentrations determined by 0.1 N HCl extraction (Korean Standard Method for Soil Pollution) were almost identical to the cumulative concentrations determined for the first three weakly-bound fractions (exchangeable + bound to carbonates + bound to Fe–Mn oxides) in the sequential extraction procedure. This suggests that 0.1 N HCl extraction can be effectively used to assess the environmentally available and/or bioavailable forms of trace metals in natural stream sediments.     

Environment impact of heavy metals on urban soil in the vicinity of industrial area of Baoji city,P.R. China

Heavy metals in soils are of great environmental concern, in order to evaluate heavy metal contents and their relationships in the surface soil of industrial area of Baoji city, and also to investigate their influence on the soils. Soil samples were collected from 50 sites, and the concentration of Pb, Zn, Cu, Cr, Ni heavy metals and the contents of characteristics in soil from industrial area of Baoji city were determined with X-ray fluorescence method. The concentrations of Pb, Zn, Cu, Cr and Ni in the investigated soils reached the amount of 2,682.00–76,979.42, 169.30–8,288.58, 62.24–242.36, 91.96–110.54 and 36.14–179.28 mg kg⁻¹, respectively. The major element Pb contents of the topsoils were determined. to highlight the influence of ‘anthropic’ features on the heavy metal concentrations and their distributions. To compare, all values of elements were much higher than those of unpolluted soils in the middle of Shaanxi province that average 16.0–26.5, 67.1–120.0, 17.8–57.0, 46.9–65.6 and 24.7–34.6 mg kg⁻¹ for Pb, Zn, Cu, Cr and Ni, respectively. An ensemble of basic and relativity analysis was performed to reduce the precipitate of Pb in soil was extremely high and greatly relativity with other elements. Meanwhile, Pb, Zn, Cu, Cr, Ni heavy metals were typical elements of anthropic activities sources, so it was easy to infer to the tracers of anthropic pollutions from the factorial analysis, which was coming from the storage battery manufactory pollutions. The pollutant distributions were constructed for the urban area which identified storage battery manufactory soot precipitate as the main source of diffuse pollution and also showed the contribution of the topsoils of industrial area of Baoji city as the source point of pollution. Consequently, the impact of heavy metals on soil was proposed and discussed. These results highlight the need for instituting a systematic and continuous monitoring of heavy metals and other forms of pollutants in Baoji city to ensure that pollution does not become a serious problem in the future.     

Spatial distribution of trace elements in floodplain alluvium of the upper Blackfoot River,Montana

The Mike Horse Mine tailings dam in western Montana was partially breached in 1975 due to heavy rainfall and a failed drainage bypass. Approximately 90,000 tons of metal and arsenic-enriched tailings flowed into Beartrap Creek and the Blackfoot River. The spatial distribution of trace elements As, Cd, Cu, Mn, Pb, and Zn in floodplain alluvium of the upper Blackfoot River were examined along 20 transects in the upper 105 river kilometers downstream from the tailings dam. Trace element concentrations decrease with distance from the failed dam, with As reaching background concentrations 15 km from the Mike Horse dam, Cd and Pb at 21 km, Cu at 31 km, and Mn and Zn at 37 km. Distance from the Mike Horse tailings dam and mine area is the dominating factor in explaining trace element levels, with R ² values ranging from 0.67 to 0.89. Maximum floodplain trace element concentrations in the upper basin exceed US. EPA ecological screening levels for plants, birds and other mammals, and reflect adverse hazard quotients for exposure to As and Mn for ATV/motorcycle use. Trace element concentrations in channel bank and bed alluvium are similar to concentrations in floodplain alluvium, indicating active transport of trace elements through the river and deposition on the floodplain. The fine fraction (<2 mm) of floodplain alluvium is dominated by sand-sized particles (2.0–0.05 mm), with Cu and Mn significantly correlated with silt-sized (0.05–0.002 mm) alluvium. Ongoing remediation in the headwaters area will not address metal contamination stored downstream in the channel banks and on the floodplain. Additionally, some trace elements (Cu, Mn and Zn) were conveyed farther downstream than were others (As, Cd, Pb).     

Evaluation of elemental enrichments in surface sediments off southwestern Taiwan

Surface slices of 20 sediment cores, off southwestern Taiwan, and bed sediment of River Kaoping were measured for major and trace elements (Al, As, Ca, Cd, Cl, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, S, Si, Ti, V, and Zn) to evaluate the geochemical processes responsible for their distribution, including elemental contamination. Major element/Al ratio and mean grain size indicate quartz-dominated, coarse grained sediments that likely derived from sedimentary rocks of Taiwan and upper crust of Yangtze Craton. Bi-plot of SiO₂ versus Fe₂O₃^T suggests the possible iron enrichment in sediments of slag dumping sites. Highest concentrations of Cr, Mn, P, S, and Zn found in sediments of dumping sites support this. Correlation analysis shows dual associations, detrital and organic carbon, for Cr, P, S, and V with the latter association typical for sediments in dumping sites. Normalization of trace elements to Al indicates high enrichment factors (>2) for As, Cd, Pb, and Zn, revealing contamination. Factor analysis extracted four geochemical associations with the principal factor accounted for 25.1% of the total variance and identifies the combined effects of dumped iron and steel slag-induced C–S–Fe relationship owing to authigenic precipitation of Fe–Mn oxyhydroxides and/or metal sulfides, and organic matter complexation of Fe, Mn, Ca, Cr, P, and V. Factors 2, 3, and 4 reveal detrital association (Ti, Al, Ni, Pb, Cu, and V), effect of sea salt (Cl, Mg, Na, and K) and anthropogenic component (As and Zn)-carbonate link, respectively, in the investigated sediments.     

Trace element distributions in aquatic sediments of Danang – Hoian area, Vietnam

 Distribution of the trace elements Cr, Cu, Ni, Pb and Zn in surficial sediments of the river/sea environment in Danang – Hoian area (Vietnam) was investigated to examine the degree of metal pollution caused by anthropogenic activities. Point sources from domestic and industrial wastes are identified as dominant contributors of trace element accumulation. Surficial sediments of Hoian River show extremely high total concentrations of Cu (Average Concentration 295 μg/g), Ni (AC 112 μg/g), Pb (AC 396 μg/g) and Zn (AC 429 μg/g) that exceed assigned safety levels ER-M. Similarly, the sediments of Han River show high Pb (AC 188 μg/g) and Zn (AC 282 μg/g) contents. In marine sediments of Thanhbinh beach Pb is also enriched (138 μg/g) above guideline levels. In contrast the sediments of the Cude River are dominated by trace element concentrations close to background values. Received: 17 December 1998 · Accepted: 6 May 1999     

A comparison of geochemical information obtained from two fluvial bed sediment fractions

 A total of 121 bed sediment samples were collected from a 5.8-km stretch of Manoa Stream, Hawaii. Samples were physically partitioned into two grain-size fractions, <63 μm and 63–125 μm, acid digested and analyzed by ICP-AES and FAAS. Non-parametric matched-pair statistical testing and correlation analysis were used to assess differences and strengths of association between the two fractions for Al, Ba, Cu, Fe, Mn, Ni, Pb, Ti and Zn. Results indicated statistically significant differences between fractions for all elements except Mn. Concentrations were significantly greater in the <63 μm fraction for Al, Cu, Pb, Ti and Zn, while Ba, Fe and Ni were higher in the 63–125 μm fraction. Though some elements had statistically significant differences between fractions (Al, Ba, Fe and Zn) percentage differences were in the range of analytical precision of the instrument and thus differences were not practically significant. Correlation analysis indicated strong positive associations for all elements between the two fractions (p<0.0001). Three contamination indices indicated similar degrees of pollution for each size fraction for four elements having an anthropogenic signal (Ba, Cu, Pb and Zn). The environmental information obtained from the 63–125 μm fraction was essentially equivalent to that from the <63 μm fraction. In this system it is clear that both bed sediment fractions indicate anthropogenic enrichment of trace metals, especially Pb, and further supports previous research that has found that aquatic sediments are critical median for tracing sources of pollution. Received: 17 August 1998 · Accepted: 30 October 1998     

Trace elements in groundwater of Hindon-Yamuna interfluve region, Baghpat district, Western Uttar Pradesh

The present study was carried out in parts of Hindon-Yamuna interfluve region to evaluate the concentration of trace elements (Al, Cr, Mn, Fe, Ni, Co, Cu, Zn, As, Se, Cd, B and Pb) in groundwater. Pre-monsoon groundwater samples were collected in 2007 from 22 locations distributed throughout the study area, and were analyzed using Inductive Coupled Plasma Mass-Spectrophotometer (ICPMS). Trace element analyses show high concentration levels for Al and Cr in almost all groundwater samples. Relatively high values are also reported for Pb, Se, Fe and Mn (as per B.I.S (1991) standard for drinking water) in few samples. These high concentrations of metal ions in groundwater were probably due to discharge of untreated effluents from Textile, dyeing and other industries. As far as Al is concerned, its source is rather enigmatic.     

The pollution of marine sediments by trace elements in the coastal region of Togo caused by dumping of cadmium-rich phosphorite tailing into the sea

 The marine coastal sediments from Togo have been analysed for the trace elements Cd, Cr, Cu, Ni, Pb, Sr, V, Zn and Zr to ascertain the geo-ecological impact of dumping of phosphorite tailings into the sea. Trace element concentrations ranged from 2–44 ppm for Cd, 22–184 ppm for Cu, 19–281 ppm for Ni, 22–176 ppm for Pb, 179–643 ppm for Sr, 38–329 ppm for V, 60–632 ppm for Zn and 18–8928 ppm for Zr. Regional distribution of trace elements in the marine environment indicates that the concentrations of Cr, Cu, Ni, Pb, V, Sr and Zn increase seawards and along the coastal line outwards of the tailing outfall, whereas Cd and Zr showed reversed spatial patterns. Sorting and transport of phosphorite particles by coastal currents are the main factors controlling the distribution of particle-bound trace metals in the coastal environment. The Cd, Sr and Zn concentrations decrease with decreasing grain size in marine coastal sediments, whereas Cr, Cu, Ni and Zn concentrations increase with decreasing grain size. Percolation and shaking experiments were carried out in laboratory using raw phosphate material and artificial sea water. Enhanced mobilization of Cd from phosphorites by contact with the sea water was observed. Received: 11 May 1998 · Accepted: 20 October 1998     

Alteration of crystalline zircon solid solutions: a case study on zircon from an alkaline pegmatite from Zomba–Malosa, Malawi

A natural, altered zircon crystal from an alkaline pegmatite from the Zomba–Malosa Complex of the Chilwa Alkaline Province in Malawi has been studied by a wide range of analytical techniques to understand the alteration process. The investigated zircon shows two texturally and chemically different domains. Whereas the central parts of the grain (zircon I) appear homogeneous in backscattered electron images and are characterised by high concentrations of trace elements, particularly Th, U, and Y, the outer regions (zircon II) contain significantly less trace elements, numerous pores, and inclusions of thorite, ytttrialite, and fergusonite. Zircon II contains very low or undetectable concentrations of non-formula elements such as Ca, Al, and Fe, which are commonly observed in high concentrations in altered radiation-damaged zircon. U–Pb dating of both zircon domains by LA-ICPMS and SHRIMP yielded statistically indistinguishable U–Pb weighted average ages of 119.3 ± 2.1 (2σ) and 118 ± 1.2 (2σ) Ma, respectively, demonstrating that the zircon had not accumulated a significant amount of self-irradiation damage at the time of the alteration event. Electron microprobe dating of thorite inclusions in zircon II yielded a Th–U-total Pb model age of 122 ± 5 (2σ) Ma, supporting the age relationship between both zircon domains. The hydrothermal solution responsible for the alteration of the investigated zircon was alkaline and rich in CO₃ ²⁻, as suggested by the occurrence of REE carbonates and CO₂-bearing fluid inclusions. The alteration of the crystalline, trace element-rich zircon is explained by an interface-coupled dissolution-reprecipitation mechanism. During such a process, the congruent dissolution of the trace element-rich parent zircon I was spatially and temporally coupled to the precipitation of the trace element-poor zircon II at an inward moving dissolution-precipitation front. The driving force for such a process was merely the difference between the solubility of the trace element-rich and -poor zircon in the hydrothermal solution. The replacement process and the occurrence of mineral inclusions and porosity in the product zircon II is explained by the thermodynamics of solid solution-aqueous solution systems.     

Comparison between non-residual Al,Co, Cu,Fe, Mn,Ni, Pb and Zn released by a three-step sequential extraction procedure and a dilute hydrochloric acid leach for soil and road deposited sediment

Surprisingly little is known about the relationship between the labile phases removed by sequential extraction procedures and those liberated by single leaches that minimally impact the alumino-silicate matrix of solids. This investigation examines the relationship between the summed concentrations of Al, Co, Cu, Fe, Mn, Ni, Pb and Zn released by an optimized 3-step standardized sequential extraction procedure and those released by a single 0.5 M HCl leach. Thirty-nine representative soil and road deposited sediment samples were examined from an urban watershed, in Honolulu, Hawaii, which has been shown to have a high degree of traffic-associated pollution. Properties of samples analyzed varied widely and exhibited a range in cation exchange capacities from 7 to 59 cmol_c/kg, pH values from 3.5 to 7.9, and organic C contents from 1 to 29%. Results indicate that the dilute HCl leach was slightly more aggressive than the sequential procedure as it removed significantly more Al, Cu, Fe, Mn and Ni; though no significant differences were observed between Co, Pb and Zn concentrations liberated by the two approaches. Both approaches showed limited dissolution of the crystal lattice with ⩽9% of the total Al liberated. Regardless of approach, element mobility was the same with the order being: Pb>Mn>Zn>Co≈Cu>Ni>Fe ∼ Al. Regression analysis indicated highly significant (P<0.0001) logarithmic relationships between the two digestion procedures, with coefficients of determination (r²) ⩾92% for all elements except Fe (54%) and Ni (64%). Further support for the strong relationships between elements liberated by both digestions was gained from geochemical contrasts between anomalous and background levels and concentration enrichment ratios. This was particularly true for Pb and Zn, the most anthropogenically enhanced trace metals in the watershed. All data indicated that a dilute HCl leach was a valuable, rapid, and cost-effective analytical tool in contamination assessment.     

The relationship between soil geochemistry and die back of montane forests in Sri Lanka: a case study

Tropical montane forests of Sri Lanka form a unique ecosystem with more than 50% of endemic plant species. It has been noted that trees, belonging to different size and age classes of these forest, have been dying due to a yet unknown factor. This phenomenon was first observed in the Horton Plains National Park, which is a high plateau, composed of tropical montane forests. Later dying of forests were observed at several areas including Hakgala montane forest. Physical parameters trace nutrients as well as toxic element concentrations in soils, were studied in order to identify the possible geochemical factors behind the forest die back. Systematic soil sampling was carried out covering the entire Horton Plains National Park and random samples were collected from Hakgala montane forest. Samples were analyzed for available Fe, Mn, Zn, Cu, Ni, Cd, Al and Pb using standard colorimetric and atomic absorption spectrometric procedures. Physical parameters such as pH, moisture content, and conductivity of the samples were also measured. Among extractable micro-nutrients Cu and Zn, and Ni show no deficiency or excess levels. However, the recorded available high concentrations of Fe, Mn and Al can be toxic to certain montane plant species. Acidic moist soil of the area may enhance the toxic effects of these elements. Possible source of these elements should be the underground lithology of the area. According to the results obtained, there is a relationship between forest die back and high Pb concentrations. The same phenomenon was also observed in the Hakgala forest. The distribution pattern of Pb in the Horton Plains coincides well with the die back distribution pattern. The observed Pb values at Horton Plains and Hakgala are almost similar to values observed at Pannipitiya and Dombagaskanda locations, which are located close to main roads carrying heavy traffic. It is quite possible therefore, that Pb toxicity may be a significant factor behind the forest die back even though other factors should not be completely ruled out at this juncture. Strong monsoon winds, bringing Pb from the polluted southwestern part of the country, can be the most possible source of soil Pb. Further studies however are indeed necessary to confirm the conclusion.     

Heavy metal contamination of coastal lagoon sediments by anthropogenic activities: the case of Nador (East Morocco)

Nador lagoon sediments (East Morocco) are contaminated by industrial iron mine tailings, urban dumps and untreated wastewaters from surrounding cities. The lagoon is an ecosystem of biological, scientific and socio-economic interests but its balance is threatened by pollution already marked by biodiversity changes and a modification of foraminifera and ostracods shell structures. The aim of the study is to assess the heavy metal contamination level and mobility by identifying the trapping phases. The study includes analyses by ICP-AES and ICP-MS, of, respectively, major (Si, Al, Mg, Ca, Fe, Mn, Ti, Na, K, P) and trace elements (Sr, Ba, V, Ni, Co, Cr, Zn, Cu, As, Pb, Cd) in sediments and suspended matter, heavy metals enrichment factors calculations and sequential extractions. Results show that sediments contain Zn, Cu, Pb, V, Cr, Co, As, Ni with minimum and maximum concentrations, respectively, of 4–1190 μg/g, 4–466 μg/g, 11–297 μg/g, 11–194 μg/g, 9–139 μg/g, 1–120 μg/g, 4–76 μg/g, 2–62 μg/g. High concentrations in Zn are also present in suspended matter. The enrichment factors show contamination in Zn, Pb and As firstly induced by the mining industry and secondly by unauthorized dumps and untreated wastewaters. Cr and Ni are bound to clays, whereas V, Co, Cu and Zn are related to oxides. Thus, the risk in metal mobility is for the latter elements and lies in the oxidation–reduction-changing conditions of sediments.     

Status of anthropogenically induced metal pollution in the Kanpur-Unnao industrial region of the Ganga Plain, India

 The Ganga Plain is one of the most densely populated regions and one of the largest groundwater repositories of the Earth. For several decades, the drainage basin of the Ganga Plain has been used for the disposal of domestic and industrial wastes which has adversely affected the quality of water, sediments and agricultural soils of the plain. The concentrations of Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sn, Zn and organic carbon were determined in river sediments and soils of the Ganga Plain in the Kanpur-Unnao industrial region in 1994 and 1995 (pre-monsoon period of April–May). High contents (maximum values) of C-org (12.0 wt. %), Cr (3.40 wt. %), Sn (1.92 wt. %), Zn (4000 mg/kg), Pb (646 mg/kg), Cu (408 mg/kg), Ni (502 mg/kg) and Cd (9.8 mg/kg) in sediments (<20 μm fraction); and C-org (5.9 wt. %), Cr (2.16 wt. %), Sn (1.21 wt %), Zn (975 mg/kg) and Ni (482 mg/kg) in soils (<20 μm) in the pre-monsoon period of 1994 were found. From 1994 to 1995 the contents of Fe and Sn in sediments increase whereas those of C-org, Cd, Cu, Ni and Zn decrease. Considering the analytical errors, Al, Co, Cr, Mn and Pb do not show any change in their concentrations. In soils, the contents of Cd, Fe and Sn increase whereas those of Ni decrease from 1994 to 1995. Aluminium, Co, Cr, Cu, Mn, Pb and Zn do not show any change in their concentrations from 1994 to 1995. About 90% of the contents of Cd, Cr and Sn; 50–75% of C-org, Cu and Zn; and 25% of Co, Ni and Pb in sediments are derived from the anthropogenic input in relation to the natural background values, whereas in soils this is the case for about 90% of Cr and Sn; about 75% of Cd; and about 25% of C-org, Cu, Ni and Zn. The sediments of the study area show enrichment factors of 23.6 for Cr, 14.7 for Cd, 12.2 for Sn, 3.6 for C-org, 3.2 for Zn, 2.6 for Cu and 1.6 for Ni. The soils are enriched with factors of 10.7 for Cr, 9.0 for Sn, 3.6 for Cd, 1.8 for Ni and 1.5 for Cu and Zn, respectively. Received: 3 March 1998 · Accepted: 15 June 1998     

Fe–Al–organic Colloids Control of Trace Elements in Peat Soil Solutions: Results of Ultrafiltration and Dialysis

Size fractionation of ~40 major and trace elements (TE) in peat soil solutions from the Tverskaya region (Russia) has been studied using frontal filtration and ultrafiltration through a progressively decreasing pore size (5, 2.5, 0.22 μm, 100, 10, 5, and 1 kD) and in situ dialysis through 6–8 and 1 kD membranes with subsequent analysis by ICP-MS. In (ultra) filter-passed permeates and dialysates of soil solutions, Fe, Al, and organic carbon (OC) are well correlated, indicating the presence of mixed organo-mineral colloids. All major anions and silica are present in “dissolved” forms passed through 1 kD membrane. According to their behavior during filtration and dialysis and association with mineral or organic components, three groups of elements can be distinguished: (i) species that are weakly affected by size separation operations and largely (>50–80%) present in the form of dissolved inorganic species (Ca, Mg, Li, Na, K, Sr, Ba, Rb, Cs, As, Mn) with some proportion of small (1–10 kD) organic complexes (Ca, Mg, Sr, Ba), (ii) biologically essential elements (Co, Ni, Zn, Cu, Cd) mainly present in the fraction smaller than 1 kD and known to form strong organic complexes with fulvic acids, and, (iii) elements strongly associated with aluminum, iron and OC in all ultrafiltrates and dialysates with 30–50% being concentrated in large (>10 kD) colloids (Ga, Y, REEs, Pb, Cd, V, Nb, Sn, Ti, Zr, Hf, Th, U). For most trace metals, the proportion in the colloidal fraction correlates with their first hydrolysis constant. This implies a strong control of negatively charged oxygen donors present in inorganic/organic colloids on TE distribution between aqueous solution and colloid particles. It is suggested that these colloids are formed during plant uptake of Al, Fe, and TE from mineral matrix of deep soil horizons and their subsequent release in surface horizons after litter degradation and oxygenation on redox or acid/base fronts. Dissolved organic matter stabilizes Al/Fe colloids and thus enhances trace elements transport in soil solutions.     

Factor analysis of the elemental composition of <Emphasis Type="Italic">Pteridium aquilinum</Emphasis> from serpentine and granite soils as a tool in the classification of relations between this composition and the type of parent rock in the Ślęża Massif in Lower Silesia,Poland

Concentrations of the elements N, P, K, Ca, Mg, S, Fe, Mn, Cu, Zn, Ni, Cr, Co, Mo, Cd and Pb were measured in serpentine and granite soils and in the fern Pteridium aquilinum sampled from the Ślęża Massif in Lower Silesia, Poland. The serpentine soils were typical for serpentine soils in general with deficiency of K and Ca and excess of Mg, Ni and Cr. The principal component analysis (PCA) ordination based on the matrix of concentrations of elements in plants growing on serpentine and granite soils enabled the identification of the parent material from which ferns in this study were collected. This method indicated that the ferns from granite soils were distinguished by higher concentrations of Mo and Pb, while those from serpentine soils were distinguished by higher concentrations of Mg, Ni, Cr and Co. These differences in bioaccumulation reflect the higher concentrations of total and plant-available forms of Mg, Ni, Cr, Co in serpentinite and the higher concentrations of total Mo and total and plant-available Pb in granites as reported in literature. The different parent material types in the Ślęża Massif on which the investigated soils were developed influence the concentration and type of elements accumulated in P. aquilinum.     

Trace element geochemistry in topsoil from East China

The concentrations of 23 trace elements in 50 topsoil samples collected from sites ranging between 18°19′N and 49°13′N in East China were analyzed. Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, and Ta have mean contents more than two times higher than in the continental upper crust. Three elements, Rb, Sr, and Ba, are present at lower concentrations than in the continental upper crust. Finally, a group of elements consisting of Ge, Y, Zr, Nb, Sc, Hf, Pb, Th, and U are present at concentrations 1–2 times higher than in the continental upper crust. However, concentrations of trace elements are mainly affected by parent rock. The contents of Sc, Ti, V, Cr, Mn, Co, and Cu for 29 soils from basalt were found to increase from north to south, whereas Rb, Sr, and Ba contents were found to decrease. In addition, element concentration shows a close relationship with annual average temperature (AAT) as well as annual average precipitation (AAP). Since the 29 soils are all from basalt, the trends of the elemental contents should reflect the influence of climate, which determines the intensity of weathering. These elemental trends suggest that the content of certain elements may indicate the intensity of basalt weathering. Ba/Nb and Sr/Nb ratios were both found to have good correlations with AAT and AAP in this study, which means that these ratios can also indicate the intensity of chemical weathering of basalt.     

Atmospheric wet deposition of trace elements to central Tibetan Plateau

To investigate trace elements in wet precipitation over the Tibetan Plateau (TP), a total of 79 event-based precipitation samples were collected from September 2007 to September 2008 at Nam Co Station. Samples were analyzed for concentrations of Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb using inductively coupled plasma-mass spectrometry (ICP-MS). The annual volume-weighted concentrations of elements were generally comparable to other background sites, and much lower than urban areas. The enrichment factors (EF) showed that, in comparison with the Tibetan soils, the wet precipitation had elevated concentrations of Cr, Co, Ni, Cu, Zn, Cd and Pb, probably indicating their anthropogenic origins. Other elements (Al, Fe, Mn and V) with enrichment factor value of <10 may derive mainly from crustal sources. The principal component analysis further confirmed the two different groups of elements in wet deposition samples. The backward trajectories were calculated for each precipitation event using the NOAA HYSPLIT model. The results indicated significant differences of EF for trace elements of anthropogenic origin between the summer monsoon and non-monsoon seasons. The data obtained in the present study indicated that pollutants can affect remote high altitude regions like the Tibetan Plateau through long-range transport, especially in the summer monsoon season.     

Geochemical factors controlling accumulation of major and trace elements in Greenland coastal and fjord sediments

 The major (Al, Ti, Ca, Mg, Fe, Mn, Si) and trace element (Cd, Cr, Cu, Hg, Li, Ni, Pb, V, Zn) concentrations in surficial (<20 cm) sediments from fjords and open coastal waters around Greenland have been determined. Regionally, high concentrations of Fe, Ti, Mg, Cr, Cu, Ni, and V occur in some west and east coast sediments, but they appear to be natural in origin, as there is no indication of anthropogenic influence. Chemical partition indicates that most of the heavy metals are structurally bound in various silicate, oxide, and sulfide minerals. These host minerals occur more or less equally in the coarse and fine sediment fractions (material >63 μm and <63 μm) and have accumulated at the same rate as other detrital clastic material. Provenance and glaciomarine deposition are the main factors controlling the abundance and distribution of the major and trace elements. The chemical composition reflects the mineralogical differences in the provenance of glacial marine material deposited by water and ice adjacent to Greenland. The main source of the sediments enriched in Ti, Fe, Mg, Cr, Cu, Ni, and V appears to be material derived from the volcanic rocks of the Mesozoic-Tertiary Provinces of Greenland by glacial erosion. Received: 26 June 1995 · Accepted: 11 August 1995