Baseline Levels of Metals in Volcanic Soils of the Azores (Portugal)

Data on metal concentrations present in the soils of the Azores (Portugal) are scarce. The goal of this study was to measure the current levels of several metals in the top horizon of soils of two areas, distinguishable by their volcanic activity and physical characteristics, in order to establish some baseline concentrations of these elements. Soil samples were taken in similar ways from five sites in a volcanically active area and another five sites in an area without volcanic activity. Particle-size fractions, % organic matter, moisture content, pH, and major and trace elements compositions were measured. In general, the concentrations of trace metals in the soils from Santa Maria (inactive volcanism) were higher than those from Furnas (active volcanism), with the exception of Zn. The soils from Furnas, which have slightly lower pH and less % clay-silt than Santa Maria, will probably make such trace metals as Zn become more readily bioaccessible, and therefore pose a larger threat to living organisms inhabiting these soils.     

Changes in Bacterial Community Structure and Abundance in Agricultural Soils under Varying Levels of Arsenic Contamination

Arsenic contamination from groundwater used to irrigate crops is a major issue across several agriculturally important areas of Asia. Assessing bacterial community composition in highly contaminated sites could lead to the identification of novel bioremediation strategies. In this study, the bacterial community structure and abundance are assessed in agricultural soils with varying levels of arsenic contamination at Ambagarh Chauki block, Chhattisgarh, India, based on polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) of the 16S rRNA gene and the most probable number-polymerase chain reaction (MPN-PCR). The results revealed that the bacterial communities of arsenic-contaminated soils are dominated by β-proteobacteria (36%), γ-proteobacteria (21%), δ-proteobacteria (11%), α-proteobacteria (11%), and Bacteroidetes (11%). The bacterial composition of high arsenic-contaminated soils differed significantly from that of low arsenic-contaminated soils. The Proteobacteria appeared to be more resistant to arsenic contamination, while the Bacteroidetes and Nitrospirae were more sensitive to it. The bacterial abundance determined by MPN-PCR decreased significantly as As-toxicity increased. In addition to As, other trace metals, like Pb, U, Cu, Ni, Sn, Zn and Zr, significantly ( p < 0.01) explain the changes in bacterial structural diversity in agricultural soils with different level of arsenic contamination, as determined by canonical correspondence analysis (CCA).     

Bioavailability of Potentially Toxic Elements in Foraged Fruits from a Former Industrial Site

Samples of foraged fruits from a former industrial site have been analyzed for potentially toxic elements (PTEs) (i.e., As, Cd, Cr, Cu, Ni, Pb, and Zn). The foraged fruit (blackberries, rosehips, and sloes) was gathered over two seasons along with samples of soil from the same sampling areas. All samples were acid digested, using a microwave oven, and then analyzed by inductively coupled plasma mass spectroscopy (ICP-MS). The concentration levels of the selected elements in foraged samples varied between not detectable limits and 24.6 μg/g (Zn). The soil-to-plant transfer factor was assessed for the PTEs. In all cases, the transfer values obtained were less than 1.00, indicating that the majority of the PTEs remains in the soil and that the uptake of PTEs from soil to plant at this site is not significant.     

Contamination Levels Remaining in Aznalcóllar Spill-Affected Soils (Spain) Following Pyritic Sludge Removal

Potentially toxic elements (PTE) in aqua regia extracts were analyzed by ICP in order to determine the remaining degree of contamination of the selected points along Agrio and Guadiamar rivers. The studied area was affected in 1998 by the accidental spillage from a flotation plant for complex sulfides located at Aznalcóllar (Spain), it was covered by acidic waters and pyritic sludge. Emergency response for the remediation of the contaminated soils, for avoiding greater ecological impact, and waiting for possible ulterior remedial actions, was the removal of the superficial sludge. Sampling was done after the sludge removal operations 1 year after the spill, at different depths down to 300?cm. The results show that the soils affected are still contaminated by several PTE at different degrees and depths depending on their particular conditions. In general, superficial soil samples became highly contaminated. The contamination of soils is due, in general, to processes of sludge infiltration and PTE leaching. The sludge infiltration is due, in part, to the heavy machinery used to remove the sludge. A moderate degree of contamination remains in some soils down to 120 or 300?cm.     

Modeling Sorption of Cd,Hg and Pb in Soils by the NICA-Donnan Model

Metal adsorption is an important process at the soil-solution interface that controls metal bioavailability and toxicity. In this study, batch adsorption experiments were conducted to investigate the binding of Cd, Hg and Pb in soils collected from around metal smelters in Quebec and Ontario, Canada. It was found that soil organic matter enhanced the retention of Cd, Hg and Pb. Assuming that the surfaces of soil particles behaved similarly to organic matter, we used the Non-Ideal Competitive Adsorption (NICA)-Donnan model to derive the parameters for surface complexation of the three metals. The shape of the Cd, Hg and Pb adsorption isotherms are briefly discussed with respect to the results of the experimental measurements and the model predictions. The average values of the NICA-Donnan model parameters could be used to give reasonable predictions of metal sorption in the soils of this study.     

Arbuscular mycorrhizal fungi in the growth and extraction of trace elements by Chrysopogon zizanioides (vetiver) in a substrate containing coal mine wastes

Vetiver (Chrysopogon zizanioides) is a fast-growing, high biomass producing plant employed for environmental rehabilitation. The study evaluated the effects of arbuscular mycorrhizal fungi (AMF) on the growth and trace element phytoextracting capabilities of vetiver in a substrate containing coalmine wastes in Southern Brazil. AMF included Acaulospora colombiana, Acaulospora morrowiae, Acaulospora scrobiculata, Dentiscutata heterogama, Gigaspora margarita, and Rhizophagus clarus. Among those, A. colombiana, G. margarita, and R. clarus promoted higher growth. AMF stimulated average increments in the accumulated P of 82% (roots), 194% (shoots first harvest—90 days) and 300% (shoots second harvest—165 days) and affected the phytoextraction of trace elements by vetiver, with larger concentrations in the roots. Plants inoculated with A. colombiana, A. morrowiae, and A. scrobiculata, in addition to the control, presented the highest levels of Cu and Zn in the roots. Overall, G. margarita stimulated the highest production of biomass, and, therefore, showed the most significant levels of trace elements in the plants. This work shows the benefits of certain AMF (especially A. morrowiae, G. margarita, and R. clarus) for the production of biomass and P uptake by vetiver, demonstrating the potential of those species for the rehabilitation of coal-mine-degraded soils.     

Contamination of Floodplain Soils along the Wupper River,Germany, with As,Co, Cu,Ni, Sb,and Zn and the Impact of Pre-definite Redox Variations on the Mobility of These Elements

This study demonstrates that floodplain soils of the River Wupper, Germany, are seriously contaminated with metal(loid)s. We used an automated biogeochemical microcosm system allowing controlled variation of redox potential (E_H) to assess the impact of pre-definite redox conditions on the dynamics of arsenic (As), cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), antimony (Sb), and zinc (Zn) in homogenized soil material taken from an acid floodplain soil. The concentrations of Co, Cu, Mn, Ni, Sb, and Zn in soil solution were low at low E_H, possibly due to the precipitation of metal sulfides, and increased with rising E_H, presumably caused by their association with dissolved organic carbon (DOC). A significant positive correlation between metal/DOC-ratio and E_H indicated that the binding of the metals to DOC shifted from stronger to weaker when E_H rose. Decreasing As concentrations with increasing E_H in soil solution indicated co-precipitation with Fe(hydr)oxides and/or oxidation of more soluble As(III) to less soluble As(V) during oxidation. The other studied elements seemed not to co-precipitate with newly formed Fe(hydr)oxides when E_H rose, possibly due to the prevailing low pH. In the future, the specific role of DOC and sulfur chemistry on metal(loid) dynamics should be elucidated more fully, and similar studies should be conducted with additional frequently flooded soils worldwide to verify these results.     

Zinc and Copper Bioaccumulation in Brassica napus at Flowering and Maturation

The aim of this research was to investigate the capability of Brassica napus to bioaccumulate zinc and copper from artificially contaminated soil at the flowering and maturation phenological stage. The trial was set up in a greenhouse and the plants were cultivated in pots. The agricultural soil utilized was contaminated with zinc and copper sulfate (300 and 600 mg/kg, respectively). The soil and plant samples were simultaneously collected during the flowering (8 weeks after seeding) and maturation (harvest time, 13 weeks after seeding) stages, and the heavy metal concentrations were then analyzed. The production of vegetable biomass and the length of the roots were measured. The results showed that B. napus accumulated zinc and copper and translocated these elements in different ways in the harvestable parts of the plants. The zinc bioaccumulation was higher than that of copper. At flowering, zinc was mainly accumulated in the shoots (stems + leaves). Copper was particularly accumulated in the roots, during the entire life cycle. Taking into account the biomass production, the highest heavy metal removal by the shoots (above‐ground parts) occurred at the flowering stage for both zinc and copper. The high bioavailability of zinc and copper in the soil did not severely affect the root length and the biomass production.     

Heavy Metal Contamination in the Brownfield Soils of Cleveland

The results esults of a survey of heavy metal contamination at Cleveland area brownfields and public spaces are presented. Soils were analyzed using a 24?h, 1N HCl extraction procedure. The study was conducted to seek brownfield soils that manifest properties of “old” sequestered contamination and to develop a better understanding of the nature and extent of heavy metal burdens at brownfield sites in the Greater Cleveland area. The results indicated that Cleveland brownfields commonly yield soil burdens well above remediation triggers for residential soils and often yield values above industrial remediation triggers. It was also discovered that public areas in the vicinity of brownfields commonly have heavy metal contamination significantly above background levels and occasionally above residential remediation triggers. These results indicate that brownfields redevelopment initiatives should proceed with caution. The appropriate remediation goals or restrictions must be imposed to control urban exposure to heavy metal contamination.     

Impact of Land-Use Patterns on Chemical Properties of Trace Elements in Soils of Rural,Semi-Urban,and Urban Zones of the Niger Delta,Nigeria

The study of the concentrations of Cr, Zn, Cd, Pb, Ni, and Cu in soils under different land uses in rural, semi-urban, and urban zones in the Niger Delta was carried out with a view to providing information on the effects of the different land uses on the concentrations of trace elements in soils. Our results indicate significant variability in concentrations of these metals in soils under different land uses in rural, semi-urban, and urban zones. The maximum concentrations of metals in the examined soil samples were 707.5 mg.kg^?1, 161.0 mg.kg^?1, 2.6 mg.kg^?1, 59.6 mg.kg^?1, 1061.3 mg.kg^?1, and 189.2 mg.kg^?1 for Cr, Zn, Cd, Pb, Ni, and Cu, respectively. In the rural zone, the cassava processing mill is a potent source of Ni, Cr, Cu, and Zn while agricultural activities are a source of Cd, and automobile emissions and the use of lead oxide batteries constitute the major sources of Pb. In the urban zone, soils around the wood processing mill showed elevated concentrations of Cu, Cr, Zn, and Ni, while soils around automobile mechanic works and motor parks showed elevated levels of Pb. Elevated Cd concentrations were observed in soils under the following land uses: urban motor park, playground, welding and fabrication sheds, and metallic scrap dump. The contamination/pollution index of metals in the soil follows the order: Ni > Cd > Cr > Zn > Cu > Pb. The multiple pollution index of metals at different sites were greater than 1, indicating that these soils fit into “slight pollution” to “excessive pollution” ranges with significant contributions from Cr, Zn, Cd, Ni, and Cu.     

Study of Heavy Metal Distribution in Soils Impacted with Crude Oil in Southern Nigeria

The study presents the levels and enrichment factors of heavy metals in soils of southern Nigeria that have received significant impact of crude oil spillage. The results revealed that the concentrations of heavy metals in the examined soils fitted into levels found in agricultural soils except for cadmium. Heavily impacted sites showed elevated levels of heavy metals compared to less impacted sites and background levels. The mean enrichment factors for Cd, Cu, Cr, Pb, Mn, Ni, and Zn were 37.3, 2.8, 14.4, 14.0, 0.77, 5.4, and 1.27 for topsoil and 37.5, 1.30, 7.81, 1.59, 4.12, and 1.28 for subsoil, respectively. This clearly indicates that there is gradual build-up of heavy metals in these soils as a result of the oil spillage and related anthropogenic activities in this area.     

Proximal Spectral Sensing to Monitor Phytoremediation of Metal-Contaminated Soils

Assessment of soil contamination and its long-term monitoring are necessary to evaluate the effectiveness of phytoremediation systems. Spectral sensing-based monitoring methods promise obvious benefits compared to field-based methods: lower cost, faster data acquisition and better spatio-temporal monitoring. This paper reviews the theoretical basis whereby proximal spectral sensing of soil and vegetation could be used to monitor phytoremediation of metal-contaminated soils, and the eventual upscaling to imaging sensing. Both laboratory and field spectroscopy have been applied to sense heavy metals in soils indirectly via their intercorrelations with soil constituents, and also through metal-induced vegetation stress. In soil, most predictions are based on intercorrelations of metals with spectrally-active soil constituents viz., Fe-oxides, organic carbon, and clays. Spectral variations in metal-stressed plants is particularly associated with changes in chlorophyll, other pigments, and cell structure, all of which can be investigated by vegetation indices and red edge position shifts. Key shortcomings in obtaining satisfactory calibration for monitoring the metals in soils or metal-related plant stress include: reduced prediction accuracy compared to chemical methods, complexity of spectra, no unique spectral features associated with metal-related plant stresses, and transfer of calibrations from laboratory to field to regional scale. Nonetheless, spectral sensing promises to be a time saving, non-destructive and cost-effective option for long-term monitoring especially over large phytoremediation areas, and it is well-suited to phytoremediation networks where monitoring is an integral part.     

Controlling Factors and Pollution Assessment of Potentially Toxic Elements in Topsoils of the Issyk-Kul Lake Region,Central Asia

The Issyk-Kul Lake region is well known for its magnificent scenery and unique scientific significance. With multivariable statistical methods, the contents of several geochemical elements (Fe, Mn, V, Zn, Cr, Co, Ni, Cu, As, Mo, Cd, Sb, Tl, Pb, and Hg) and total organic matter of 61 topsoil samples were analyzed, and then, the results were used to assess the environmental factors controlling the concentrations of potentially toxic elements (PTE) in the region. The results showed that most of the elements including Fe, Mn, V, Cr, Co, Ni, Cu, As, and Sb reflected the natural state, but several PTE (Zn, Mo, Hg, Cd, Pb, and Tl) had been influenced by anthropogenic factors. Among these, Zn, Mo, Hg, and Cd were significantly correlated with the organic matter content, which suggests that agricultural soils will accumulate more PTE. From the calculations for the human risk assessment of anthropogenically derived PTE (Zn, Mo, Hg, Cd, Pb, and Tl), the risks for ingestion in this region were found to be higher than those for inhalation and dermal absorption; however, the results also suggested there are no non-carcinogenic risks for all anthropogenically influenced PTE in the current state.     

Remediation of Clay Soils Contaminated with Potentially Toxic Elements: The Santo Amaro Lead Smelter,Brazil, Case

The remediation of clayey soil contaminated by potentially toxic elements is a challenging task, especially because of the low permeability and strong affinity of such toxic elements, which prevent the effective use of low-cost in situ remediation methods. The clay soil from the region of the former Santo Amaro primary lead smelter has high concentrations of potentially toxic elements, especially Pb, Cd, Sb, and Zn. This study presents a preliminary evaluation of remediation by soil washing and thermal stabilization, which can support clean-up initiatives for this site. The treatment results indicate that soil washing using EDTA can be an effective method to clean up the soil; however, the solid-liquid separation step by filtration is slow. Soil thermal treatment at temperatures higher than 800°C in an oxidant atmosphere results in the formation of ceramic structure because of the high smectite content, which stabilizes the potentially toxic elements. The estimated cost for remediation by soil excavation, replacement, and stabilization, of the critically contaminated site at the Santo Amaro region is estimated at about 20 to 30 million US$.     

Organic Contamination in Soils Associated with Cemeteries

This study examined the organic contaminants in soils from an older cemetery in Ohio. Thirty soil samples at various depths and distances from graves were obtained and analyzed using organic solvent extraction, concentration, and gas chromatography with mass selective detector. The signatures of methylene chloride-extracted organic compounds show interesting trends vertically within the cemetery, with less apparent horizontal trends. Alkanes in the 18 to 34 carbon number range dominated most core samples. However, the abundance of the lighter C₁₈ to C₂₆ alkanes is unique to the deep samples onsite. Statistically, depth is relatively unimportant in predicting the abundances of the heavier compounds, whereas distance from the nearest grave is significant to predicting the area of light and heavy alkanes. These signatures are very similar to those obtained through maturation and release of organic matter in the subsurface. Evidence indicates release of organic compounds into the surrounding vicinity of the cemetery, but not necessarily off-site.     

水稻苗床土壤调酸后对土壤酶活性及一些营养元素的影响

水稻苗床土壤调酸后对土壤酶活性及一些营养元素的影响唐咏,梁成华,张中原,李焕珍（沈阳农业大学,１１０１６１）（沈阳市土肥工作站,１１００３４）ＥｆｆｅｃｔｓｏｆＳｏｉｌＡｃｉｄｉｆｉｃａｔｉｏｎｏｎＥｎｚｙｍｅＡｃｔｉｖｉｔｉｅｓａｎｄＮｕｔｒｉｅｎ...     

Assessment of Heavy Metals Contamination and Potential Ecological Risk in Soils Affected by a Former Mn Mining Activity,Drama District,Northern Greece

Manganese mining activities in the Drama district, northern Greece, have resulted in a legacy of abandoned mine wastes at the “25 km Mn-mine” site. Current research was focused on the western Drama plain (WDP), constituting the recipient of the effluents from Xiropotamos stream, which passes through the “25 km Mn-mine” place. A total of 148 top soil samples were collected and their heavy metals (HMs) concentrations (Mn, Pb, Zn, Cu, Cd, and As) were determined using inductively coupled plasma mass spectrometry. Enrichment factor (EF), geoaccumulation index (Igeo), and pollution load index (PLI) were calculated as an effort to assess metal accumulation, distribution, and pollution status of the soils due to the former mining activity. The overall potential ecological risk of HMs to the environment was also evaluated using the potential toxicity response index (RI). Results showed that peak values of the elements (13 wt% for Mn, 0.2 wt% for Pb, 0.2 wt% for Zn, 0.1 wt% for As, 153 mg/kg for Cu, and 27.5 mg/kg for Cd) were found in soils from sites close to and along both sides of the Xiropotamos stream. In this sector of WDP, values of EF, Igeo, and PLI classify the soils as moderately to highly polluted with Mn, Pb, Zn, Cd, and As. Based on RI values, soils in this part of WDP display considerable to very great potential ecological risk and, therefore, a remediation has to be applied. The main cause of soil contamination is considered the Xiropotamos downstream transfer and dispersion of Mn mine wastes via flooding episodes.     

Evaluation of some heavy metals toxicity in Channa punctatus and riverine water of Kosi in Rampur,Uttar Pradesh,India

This study was aimed to assess the bioaccumulation and concentration level of three heavy metals such as Chromium (Cr), Cadmium (Cd) and Lead (Pb) in the riverine water and edible fish, Channa punctatus obtained from River Kosi, Rampur, Uttar Pradesh, India. These toxic heavy metals are released into the environment because of E-waste, industrial activities, municipal urban runoff, coal burning, fertilizers etc., then paved the way into the aquatic system due to direct input, atmospheric deposition, and erosions caused by rain. There is every apprehension of aquatic animals getting exposed to elevated levels of heavy metals, thus possessing harmful effects both to flora and fauna. The concentrations of Cd, Cr and Pb in water were found to be 0.051 ± 0.026, 1.091 ± 0.408, and 0.019 ± 0.002 whereas in the kidneys of Channa punctatus, as 0.076 ± 0.208, 0.482 ± 0.059, and 0.127 ± 0.705 respectively.     

Trace Elements in Street and Household Dusts in Amman,Jordan

This research aims at quantifying the concentrations of heavy metals within the home environment in Amman, the capital city of Jordan, and to compare the total concentrations of indoor dusts to that of exterior dusts and soils. Housedust samples were collected from different zones of Amman. Street dust samples and garden soil samples were collected in the immediate vicinity within 10–50 m of each residence. The geometric mean concentrations of metals in the household dust were Pb, 169 mg/kg; Cd, 2.92 mg/kg; Zn, 1985 mg/kg; Cu, 133 mg/kg; Cr, 66 mg/kg; Co, 21 mg/kg; Ni, 31 mg/kg; Mn, 284 mg/kg; Be, 3.0 mg/kg; Ba, 43 mg/kg; B, 697 mg/kg and Al, 1441 mg/kg. Comparisons of household dust, garden soil and street dust were based on the same particle size fraction. Results showed housedust samples to contain higher concentrations for Pb, Zn, Cr, Ni, Cd, Cu and B, than either street dust or garden soil samples. However, the differences between Pb and Cr levels in the three different sample categories were insignificant. Enrichment factor calculations and the enrichment factor ratios indicated that patterns of enrichment of indoor dust differ from that of exterior dusts.     

压力罐消解ICP-MS法同时测定全血中5种微量元素

为了建立同时测定全血中微量元素铬、锰、砷、镉、铅的电感耦合等离子体质谱(ICP-MS)分析法,采用压力罐消解技术对全血样品进行消化,使用ICP-MS法对全血中的五种微量元素铬、锰、砷、镉、铅含量进行测定。结果显示,全血样品中所测定的5种微量元素浓度为0~0.20μg·mL-1时,线性关系良好,相关系数r>0.999,各元素相对标准偏差(RSD)均小于5.0%(n=6),加标回收率为88.4%~107.6%,本法对铬、锰、砷、镉、铅的最低检出浓度分别为0.60、1.4、0.70、0.048、0.18μg·L-1。表明运用ICP-MS同时检测全血中微量元素具有良好的准确度和精密度、灵敏度高、检出限低、元素之间的干扰少,方法高效可行。