Behaviour of Potassium and Trace Elements in Rhizosphere of Flue-Cured Tobacco (Nicotiana Tabacum L.)

The study on the behaviour of potassium,phosphate and trace elements,Fe,Mn,Cu and Zn,in the rhizosphere of different varieties of flue-cured tobacco (Nicotiana tabacum L.)with high and low potassium application rate with rhizobag technique showed that soil available K,soil available P,and slow available K was in depletion status,whereas DTPA extractable Fe,Mn,Zn and Cu accumulated obviously in rhizosphere.The depletion and accumulation rates of mineral nutrients differed in degree with K application rate,soil type,and tobacco variety.The content of available K in both rhizosphere and bulk soil and K concentration in tobacco leaf increased significantly,and the available P in rhizosphere dropped with more K application.The DTPA-Fe content of red soil much lower in pH was higher than that of calcareous soil in bulk soil.But the DTPA-Fe content of calcareous soil was much higher than that of red soil in rhizosphere,which was considered perhaps to be mainly related to releasing of Fe phytosiderophore.Nitrate coule increase depletion of a vailable K in rhizosphere and also soil pH in comparision with ammonium.     

Determination of Major and Trace Elements in Plant Samples by Inductively Coupled Plasma–Mass Spectrometry

The determination of several trace elements [arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), molybdenum (Mo), nickel (Ni), and lead (Pb)] in plant samples using inductively coupled plasma–mass spectrometry (ICP‐MS) was evaluated. It was established experimentally that moderate amounts (0.2–2%) of dissolved solids decreased the analyte signals significantly. Internal standardization with Rh was efficiently used to compensate for these matrix effects. The accuracy of the method was verified using reference materials digested according to two different procedures: dry ashing and microwave digestion. No significant differences were observed between measured concentrations and certified values. The investigation was next extended for the determination of major elements [aluminum (Al), boron (B), calcium (Ca), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), sodium (Na), phosphorus (P), and zinc (Zn)] on the same reference materials. The ICP‐MS values agree well with the values supplied. However, it appeared that Sc was the most useful internal standard for major elements.     

Selective Dissolution Analysis of Major and Trace Elements in an Allophanic Andisol Acidified by Long‐Term Fertilizer Application

A long‐term (61 years) experimental field was used to examine the effect of acidification on the chemical composition of an allophanic Andisol in northeastern Japan. The pH values of the 1:10 water extract of the plow layer soils were 4.1, 4.7, and 6.2 for three fertilizer application treatments: chemical fertilizers only (CF), CF and compost (CFC), and CFC with liming, respectively. Three batch dissolution analyses were conducted to determine water‐soluble and exchangeable (D1), D1 plus, inorganically bound elements to noncrystalline clays and organically bound elements (D2), and total concentration of elements (TCE, 45 elements). The D1 fraction of 20 elements increased, and that of eight decreased with acidification. The D2 fraction of lithium increased, and that of eight elements decreased with acidification. Because the D2 fraction of many other elements and TCE were not strongly altered, present acidification of this soil can be restored with liming and other necessary amendments.     

Investigation of Soil Concentrations of Persistent Organic Pollutants, Trace Elements, and Anions Due to Iron–Steel Plant Emissions in an Industrial Region in Turkey

The spatial distribution of several air pollutants emitted from iron–steel industries in Hatay-Iskenderun industrial region in Turkey was investigated by measuring their concentrations in soil. Collected soil samples (n?=?20) were analyzed for persistent organic pollutants (POPs; i.e., polycyclic aromatic hydrocarbons, polychlorinated biphenyls, polybrominated diphenyl ethers, and polychlorinated naphthalenes), anions, and trace elements. Generally, all measured POP concentrations and marker trace elements for iron–steel industry (Zn, Pb, and Cu) were high relative to those reported previously for rural and urban areas around the world, and they were comparable to those measured recently in a similar industrial region (Aliaga, Izmir, Turkey). For all investigated POPs, elements, and anions, the highest concentrations were measured at points located north of the iron–steel industries where their emissions are transported by the prevailing southerly winds. The spatial distribution and levels of POPs, elemental, and anionic concentrations indicated that the iron–steel plants in Hatay-Iskenderun region are important sources for these pollutants. Statistically significant relationships between several organic and inorganic pollutants further confirmed that they are emitted by common sources (iron–steel plants).     

Forms of Rare Earth Elements in Soils: Ⅱ. Differentiation of Rare Earth Elements

The present paper deals mainly with the relationships between the distribution of rare earth elements (REE) in different forms in soils and the atomic number and with the odd-even phenomenon in the distribution of ionic lanthanides in soils.The enrichment tendency of light REE relative to heavy REE in soils was pointed out on the experimental results about the proportions of Ce-group and Y-group elements in different REE forms in soils.Meanwhile,the differentiation of Tm in different soil REE forms was compared and the reasons why Tm is enriched in soils were preliminarily discussed.     

Mycoremediation of Potentially Toxic Trace Elements——a Biological Tool for Soil Cleanup: A Review

Anthropogenic and geogenic activities release potentially toxic trace elements (PTEs) that impact human health and the environment.Increasing environmental pollution stresses the need for environmentally friendly remediation technologies.Physico-chemical treatments are effective,but are costly and generate secondary pollution on-or off-site.Phytoremediation is a biological treatment that provides positive results for PTE eradication with few limitations.Mycoremediation,a type of bioremediation to use macrofungi (mushrooms) for PTE extraction from polluted sites,is the best option for soil cleanup.This review highlights the scope,mechanisms,and potentials of mycoremediation.Mushrooms produce a variety of extracellular enzymes that degrade polycyclic aromatic hydrocarbons (PAHs),polychlorinated biphenyls (PCBs),pesticides,dyes,and petroleum hydrocarbons into simpler compounds.Cadmium (Cd),lead (Pb),mercury (Hg),chromium (Cr),copper (Cu),zinc (Zn),and iron (Fe) have been effectively extracted by Phellinus badius,Amanita spissa,Lactarius piperatus,Suillus grevillei,Agaricus bisporous,Tricholoma terreum,and Fomes fomentarius,respectively.Mycoremediation is affected by environmental and genetic factors,such as pH,substrate,mycelium age,enzyme type,and ecology.The bioaccumulation factor (BAF) can make clear the effectiveness of a mushroom for the extraction of PTEs from the substrate.Higher BAF values of Cd (4.34),Pb (2.75),Cu (9),and Hg (95) have been reported for Amanita muscaria,Hypholoma fasciculare,Russula foetens,and Boletus pinophilus,respectively,demonstrating their effectiveness and suitability for mycoremediation of PTEs.     

Ratios of Closely Related Elements in Soil and Their Implications

This paper has investigated the ratios of closely related elements such as Mn, Cr, V, Ni, Co, Cu, Pb, Cd, Ba, Sr, La and Ce in the major soils of China, and the factors affecting them, and explored their use as indicators in soil formation, material transport and environmental pollution. Results show that the effect of soil-forming processes on the ratios of closely related elements varied with different elements, and became greater in the sequence of Ce/La <V/Cr=Ni/Co<Zn/Cu=Zn/Pb<Zn/Cd <Mn/Cr <Ba/Sr. The magnitude of the variation in the ratios of closely related elements depended on the chemical properties of the elements themselves, on the one hand, and the parent material and climatic conditions on the other.     

Comparison of Soil Clean-up Standards for Trace Elements Between Countries: Why do they differ? (9 pages)

Goal, Scope and Background

In the nineteen nineties most European countries issued legislation on soil protection, including soil contamination. In the case of a presumed contamination, soil investigation mostly follows a stepwise approach starting with a preliminary investigation, then an in-depth investigation and, finally, remediation. Soil clean-up standards are often foreseen as trigger criteria to determine the need for an in-depth soil investigation or for remediation. There are however large differences in soil clean-up standards. This is partly because of the different roles of soil clean-up standards in each legislative framework and partly because of differences in the soil clean-up standard (SCS) derivation procedures. Despites these differences there are large similarities in the concepts of the derivation procedures for clean-up standards. A better understanding of the differences in clean-up standards is needed. In order to clarify the variation, the background of the clean-up standards for a selected number of countries was investigated. The objective of this paper is to investigate the underlying reason why country-wide generic soil and groundwater clean-up standards of eight trace elements (cadmium, chromium (III), copper, mercury, lead, nickel, zinc and arsenic) differ between the selected countries.

Main Features

To avoid misinterpretation of the differences in application of the clean-up standards, a short overview of the legislative role of clean-up standards is given first. Differences in model concepts and parameter values are discussed, followed by a comparison of the generic soil and groundwater clean-up standards for trace elements and a discussion on the sources of variation. The influence of the use of ecotoxicological criteria and data for the derivation of soil clean-up standards will be discussed in more detail. Selected countries were Canada, the Flemish Region (Belgium), France, Germany, Great-Britain, the Netherlands, Norway, Sweden, Switzerland and United States of America (USA).

Results and Discussion

When soil clean-up standards for eight trace elements (cadmium, chromium (III), copper, mercury, lead, nickel, zinc and arsenic) were compared between the selected countries differences of more than a factor 1000 arose. Notwithstanding the use of similar derivation procedures, differences were caused by the use of different software models with their specific input data, boundary conditions and applied protection criteria for humans and the ecology. Ecotoxicological criteria tend to lower the soil clean-up standard for the selected trace elements.

Conclusions

In the countries that are included in this study, clean-up standards are used is different ways, this is for the determination of the necessity for remediation or for the need for further soil investigation. This paper shows a wide variation in the clean-up standards, which has further implication on the decision for remediation or further investigation and, hence, the financial costs of soil management. All the clean-up standards have as primary goal the protection of human health. A number of countries also include the protection of the ecological function of the soil. Differences in selected software model, (standard) parameters values, selected human toxicological and ecotoxicological criteria, are reason for a substantial variation in the clean-up standards for trace elements.

Recommendations and Perspective

. Is this variation justified? The derivation of soil clean-up standards involves - besides scientific elements - political elements, like differentiation in landuse types (agricultural, residential, recreational, industrial), receptor at risk or protection level. It is obvious that harmonization of these elements will be complicated. However, a European action programme, like the thematic strategy for soil protection, could initiate this process of harmonization. Nevertheless, soil-clean-up standards could never be uniform over the whole of Europe because they include country specific elements (geographical, ethnological) and political decisions.     

Forms of Rare Earth Elements in Soils: Ⅰ. Distribution

The distribution of rare earth element (REE) forms in soils is given in the present paper on the basis of sequential fractionation and determination of 34 representative surface soils collected from all parts of China.Results obtained show that the extraction rate of water soluble and exchangeable REE had the odd-even phenomenon and that of organically bound REE from La to Lu tended to reduce gradually with the increase of atomic number.The stability of Sc and the activity and enrichment of Tm in soils are proposed.Furthermore,the paper makes a preliminary discussion on the differences in the concentration distribution of various forms of individual REE in some soils.     

Adsorption and Desorption of Exogenous Rare Earth Elements in Soils:Ⅰ. Rate and Forms of Rare Earth Elements Sorbed

Adsorption and desorption of exogenous rare earth elements (REE) in soils were studied.Results showed that soils had strong adsorbability for REE and the rate of adsorption of REE was over 95% of the added REE in these tests.The characteristics of adsorption isotherms corresponded well with the both Freundlich and Temkin equations,but deviated from the Langmuir equation.The adsorption of REE tended to increase with the rising of soil pH.A sequential extraction method used for studing the desorption and distribution of REE sorbed in soils are also discussed.     

Spatial Differentiation of Elements in Soils on Red-Earthy Hill Landscape of Central China

Samples of 21 soil profiles and 165 top soils from an area of approximate 1.5km^2 on red-earthy hill landscape were collected and analysed.The content of Ca,Mg,K,P,Fe,Mn,Zn and Cu in soils relate with the kind of parent material and the position of topography,however,there is great variation due to the local difference of the form of soil utilization.From the difference in spatial distribution of elements content,it is believed that eight kinds of elements are lost by chemical leaching and physical translocation,meanwhile some are added (such as Ca,P,K,Mg) and some mobilized (such as Fe,Mn,Zn,Cu and P) through cultivation,fertilization and irrigation in the soils on the landscape investigated.The sectional differentiation in abundance or deficiency of elements in top soils on the landscape investigated is distinct,which is important for carrying out agricultural management and reasonable fertilization according to local conditions.     

Heavy Metals, Phosphorus and Some Other Elements in UrbanSoils of Hangzhou City, China

Health implications of inhaling and/or ingesting dust particles with high concentrations of heavy metals from urbansoils are a subject of intense concern. Understanding the geochemistry of these metals is key to their effective management. Total concentrations of heavy metals, phosphorus (P) and 8 other elements from topsoil samples collected at 82locations in Hangzhou City were measured to:a) assess their distribution in urban environments;and b) understand theirdifferentiation as related to land use. Metal mobility was also studied using a three-step sequential chemical fractionationprocedure. About 8.5%, 1.2%, 3.6%, 11.0% and 30.3% of the soil samples had Cd, Cr, Cu, Pb, and Zn concentrations,respectively, above their allowable limits for public and private green areas and residential use. However, in commercialand industrial areas, most samples had metal concentrations below their allowable limits. Statistical analyses revealedthat the 16 measured elements in urban soils could be divided into four groups based on natural or anthropic sourcesusing a hierarchical cluster analysis. Additionally, Cu, Pb, and P showed similar spatial distributions with significantpollution in commercial zones, suggesting vehicle traffic or commercial activities as dominant pollutant sources. Also, Cd,Co, Cr, Ni, Zn, Mn and Fe had the highest concentrations in industrial locations, signifying that industrial activities werethe main sources of these seven metals. Moreover, the data highlighted land-use as a major influence on heavy metalconcentrations and forms found in topsoils with large proportions of soil Cd, Co, Cr, and Ni found in residual fractionsand soil Cu, Pb and Zn mainly as extractable fractions.     

Trace Analysis of N-Nitrosamines in Water Using Solid-Phase Microextraction Coupled with Gas Chromatograph–Tandem Mass Spectrometry

A method that utilizes solid-phase microextraction (SPME) coupled with gas chromatography (GC) and chemical ionization tandem mass spectrometry (MS/MS) was developed for analyzing a group of emerging pollutants, N-nitrosamines, in water. The developed analytical method requires a water sample of less than 5 ml and only 1.5 h for complete analysis. The method detection limits for N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine, and N-nitrosodi-n-propylamine were in the range of 3.2 to 3.5 ng/l; for N-nitrosomorpholine, it was 15.2 ng/l. The method was successfully employed to measure the N-nitrosamine concentration at trace levels of nanogram per liter in four water treatment plants (WTPs) and one water distribution system. In the WTPs, only NDMA was detected in the treatment processes. Within the treatment train, NDMA was observed after chlorination. The level of NDMA significantly declined after slow sand filtration due presumably to microbial degradation. The NDMA concentration collected from consumer tap water was about 40% higher on average than that in the finished water. The excellent performance of the SPME/GC/MS/MS method in various water matrices as well as the shorter analysis time and smaller sample volume compared to currently used extraction techniques makes it an alternative means for the analysis of N-nitrosamine in drinking water, wastewater, and laboratory research with small reactors.     

Sulphur Isotopes, Trace Elements and Mineral Stability Diagrams of Waters from the Abandoned Fe–Cu Mines of Libiola and Vigonzano (Northern Apennines, Italy)

The geochemical characteristics of rills draining pyrite-chalcopyrite tailings impoundments and of bordering streams were investigated at the ophiolite-hosted Libiola and Vigonzano abandoned massive sulphide mines, northern Apennines Italy. Water samples were analysed for major and trace chemical composition, hydrogen and oxygen isotope composition, and sulphur isotope composition of aqueous sulphate. Sulphur isotope composition was determined also for some samples of ore sulphides. At Libiola, the newly acquired chemical results on waters corroborate those from previous investigations, thus providing additional support to existing geochemical models in terms of metal distribution, solid phases precipitation, reaction path modelling and mixing reaction paths, and environmental problems. At Vigonzano, the chemical characteristics of waters are similar to those at Libiola. In both localities, solution-secondary phase equilibria estimated using an updated thermodynamic dataset account for mineralogy in the field, including poorly crystalline phases like jurbanite and hydrowoodwardite. The hydrogen and oxygen isotope composition of waters at Libiola and Vigonzano agrees with their meteoric origin. Acid to neutral mine waters do not show any significant isotope shift with respect to the initial water, in spite of the oxidation of even large amounts of pyrite/chalcopyrite ore. The sulphur isotope composition of aqueous sulphate in mine rills at Libiola (δ ³⁴S?=?5.6 to 8.5‰; mean 6.5‰) matches that of massive sulphide ore (δ ³⁴S?=??0.5 to 6.7‰; mean 5.8‰), in keeping with the supergenic origin of the sulphate and related isotope effects in the sulphide oxidation process. Sulphate in mine waters at Vigonzano displays lower δ ³⁴S values in the range 0.6 to 1.5‰. The δ ³⁴S signature of massive ore specimens is within the range reported for most volcanic-hosted massive sulphide deposits, including Cyprus-type deposits.     

Post-catastrophe Analysis of the Fundão Tailings Dam Failure in the Doce River System,Southeast Brazil: Potentially Toxic Elements in Affected Soils

On November 5, 2015, after the collapse of the Fundão tailings dam, a massive amount of iron mine waste was released into the Doce River system in southeast Brazil. The aim of our study was to determine the mass fractions of potentially toxic elements in soil affected by the deposition of material by the waste wave. A preliminary screening was performed with portable X-ray fluorescence spectrometry (PXRF) and principal component analysis (PCA). The EPA 3050B method was further applied to digest the samples for quantitative determination of As, Ba, Cr, Cu, Mn, Ni, Pb, V, and Zn by inductively coupled plasma mass spectrometry. PCA was useful to classify the mine waste samples based on the Fe signal from the PXRF spectra, in spite of the heterogeneous nature of the material discharged into the Doce River system. The anomalous levels of As (up to 164 mg kg^?1) and Mn (as high as 2410 mg kg^?1) found in some mine waste and affected soil samples are within the background ranges typically observed in the soils of the Iron Quadrangle region. The toxicity characteristic leaching procedure shows no evidence of hazards regarding As, but a high natural background level of Mn was found in the mobile fraction. This preliminary environmental assessment highlights the importance of evaluation of long-term effects on soil directly impacted, as well as on the aquatic biota of the Doce River system and adjacent coastal environment given the large affected area, which includes regions with varying background levels of toxic elements.     

Microbial Activity Indices： Sensitive Soil Quality Indicators for Trace Metal Stress

Physicochemical properties, total and DTPA （diethylenetriaminepentaacetic acid）-extractable Cu, Zn, Pb and Cd contents, microbial biomass carbon （C） content and the organic C mineralization rate of the soils in a long-term trace metal-contaminated paddy region of Guangdong, China were determined to assess the sensitivity of microbial indices to moderately metal-contaminated paddy soils. The mean contents of total Cu, Zn, Pb and Cd were 251, 250, 171, and 2.4 mg kg^-1 respectively. DTPA-extractable metals were correlated positively and significantly with total metals, CEC, and organic C （except for DTPA-extractable Cd）, while they were negatively and highly significantly correlated with pH, totall Fe and Mn. Metal stress resulted in relatively low ratios of microbial biomass C to organic C and in remarkable inhibition of the microbial metabolic quotient and C mineralization rate, which eventually led to increases in soil organic C and C/N. Moreover, microbial respiratory activity showed a stronger correlation to DTPA-extractable metals than to total metal content. Likewise, in the acid paddy soils some “linked” microbial activity indices, such as metabolic quotient and ratios of basal respiration to organic C, especially during initial incubation, were found to be more sensitive indicators of soil trace metal contamination than microbial biomass C or basal respiration alone.     

Trace metal pollution in freshwater sediments of the world’s largest mercury mining district: sources,spatial distribution,and environmental implications

Purpose

The Almadén mining district has suffered long-term extraction activity, and this has left significant areas of decommissioned mining liabilities. Nowadays, the uncontrolled runoff and related erosion and transport of trace metal-enriched soils and sediments affect the whole freshwater ecosystem. The goal of this study was to distinguish geogenic from mining-related sources of trace metals in freshwater sediments, to understand their dispersion in the watershed, and, finally, to evaluate the potential environmental implications for future corrective plans.

Materials and methods

Freshwater surface sediment samples were collected from ten points along the main streams of the watershed (nine inside the mining district and one control point outside the district). Sediments were air dried and analyzed by different standard methods for pH, total major and trace element concentrations, total organic carbon, and grain size. In addition to the determination of the enrichment factor, a multi-statistical approach was applied involving discriminant analysis, Student’s t test, and Mann-Whitney U analysis.

Results and discussion

Sediments inside the district contained high levels of major and trace elements with respect to the control point. The predominance of fine fractions in these sediment samples appears to be one of the most important factors that affects trace metal concentrations. Among the trace elements, not only Hg but also As, Pb, and Zn are discriminative geochemical markers, thus allowing the identification of the different mining sources and their individual or combined impact throughout the district. Furthermore, the high enrichment factors obtained for As, Hg, Pb, and Zn with respect to the local background values highlight the persistent and severe impact from the decommissioned mines on the freshwater surficial sediments and their potential geoavailable risk for aquatic organisms.

Conclusions

The geochemistry of freshwater sediments alone demonstrates that different contamination sources are recognizable within the mining district and these can be related to the specific decommissioned mines. In addition, the discrete sources can be clearly distinguished on the basis of the statistical analysis of the geochemical data. Despite the closure of the mines, stream sediments are still the main repository of trace metals within the district, and they are therefore a potential threat to the freshwater ecosystem.

     

Effects of Various Salt–Alkaline Mixed Stresses on the State of Mineral Elements in Nutrient Solutions and the Growth of Alkali Resistant Halophyte Chloris Virgata

Chloris virgata, a naturally alkali-resistant halophyte, was studied. Various salt–alkali conditions with different salinities and pHs were established by mixing sodium chloride (NaCl), sodium bicarbonate (NaHCO₃), sodium sulfate (Na₂SO₄), and sodium carbonate (Na₂CO₃), in various proportions. The effects of these salt–alkali conditions on the state of mineral elements in nutrient solutions were analyzed using the GEOCHEM-PC program. The relative growth rate (RGR) and tillering rate of stressed C. virgata were determined. The activities of metal ions in nutrient solutions, apart from potassium (K⁺), decreased with both increased salinity and pH, and high pH resulted in precipitation of metal ions and phosphate. Consequently, the high pH of salt–alkaline mixed stress could cause severe nutrient stress in plants. However, when pH was 6.40–8.74, the effects of pH on RGR and tillering rate were not significant, and the high pH surrounding roots might be resisted by the root cells and prevented from invading the intracellular environment. Only when pH > 8.74 did the harmful action of high pH emerge, and the increased pH induced the severe decreases of RGR and tillering rate at the same salinity. The results indicated that pH adjustment outside the roots might be a key physiological mechanism for C. virgata resisting alkali stress.