Background levels of trace and ultra-trace elements in soils of Japan

Five hundred and fourteen soil samples collected from 78 sites in Japan were analyzed for their contents of trace and ultra-trace elements. We estimated the background levels (natural abundance) of 57 elements in soils. The concentration ranges were so wide that the ratios of the highest values to the lowest values were more than 100 for all the elements, with the exception of Be, Ga, Mo, Ag, In, Sn, and Ba. While the concentrations of the first transition elements (₂₁Sc to ₃₀Zn in atomic numbers) were higher than the concentration of the other elements, those of lighter (₃Li and ₄Be) and heavier elements tended to decrease, with an increase or decrease of atomic numbers, with the apparent exception of Pb, Th, and U. Concentrations of elements with even atomic numbers were, in most of the cases, higher than the concentrations of both adjacent elements with odd atomic numbers. Frequency distribution of most of the elements was strongly positively skewed. Markedly positive correlation coefficients (r>0.9) were observed among the elements within the same group in the Periodic Table in many combinations. The dendrogram obtained by cluster analysis showed that the occurrence and distribution of the elements in soils were mostly controlled by the chemical properties of each element, rather than by the nature and properties of individual soil samples. The total contents of the elements in soils were strongly dependent on the chemical composition of the parent rocks from which respective soils were derived.     

Background concentrations of elements in soils of China

Water, Air, & Soil Pollution - Mean concentrations of 62 elements, pH, organic matter and grain size have been computed for soil samples from 4,095 locations throughout mainland China The...     

Trace elements in some Northern Nigerian soils

Abstract

The concentrations of the more‐or‐less strongly retained trace elements present in the root zone of some northern Nigerian soils were determined. The soils were chosen to represent some of the more extensively distributed soil orders under cultivation in the Nigerian savanna zone. Extraction by concentrated HNO₃ was used to determine the so‐called “total”; amount of retained Cu, Zn, Pb, Ni, Cd, and B in the soils. Aqueous solutions of the chelating agents, EDTA and DTPA, were used to extract the more weakly retained Cu, Zn, Pb, Ni, and Cd; whereas, hot water was used to extract the weakly retained B. The “total”; and the more‐weakly‐retained contents of these trace elements were significantly correlated with the amount of clay, silt, and the oxalate‐extractable oxyhydroxides present in the soils; whereas, only the weakly retained elements were significantly correlated with the content of organic matter in the soil. Both the “total”; concentrations and weakly‐retained Cu, Zn, and B were so low that deficiency problems may develop in these sandy soils if cultivated more intensively on a commercial scale without due precautions. The concentrations of the weakly‐retained toxic elements, Pb, Ni, and Cd, were low indicating that industrial pollution has not yet occurred.     

Conditions related to solubility of rare and minor elements in forest soils

Soil solutions expelled by high‐speed centrifugation (13900 g) of intact soil sample cores at field moisture from 30 forest topsoils (A horizons of mainly Dystric and Eutric Cambisols, according to the FAO‐Unesco system) low in clay were subjected to analysis of 60 elements, using ICP‐MS and ICP‐AES. Concentrations measured were related to soil and soil solution properties assumed to be important for the solubility of elements, using stepwise regression analysis. On an average two thirds of the variability in soil solution concentration of elements were accounted for by, in particular, organic C concentrations, pH and/or nitrate concentrations of the solutions, varying among elements from 19 to 90 %. Concentrations of elements strongly positively related to soil solution acidity were Al, Be, Ge, Li, Ni, Pb, and Zn, strongly negatively related to acidity were Ca, Mo, and W. Most positively related to nitrate concentrations in soil solutions were B, Ba, Cd, Mg, Mn, and Sr; negatively were Nb, Ta, and Ti. Concentrations of organic C in the soil solutions correlated positively, often quite closely, with most of the other elements studied, including La, all the lanthanides, and with Ag, Br, Cr, Fe, Ga, Hf, Hg, In, P, Th, U, Y, and Zr. Soluble organic compounds were apparently ’︁carriers’ of these elements in the soil solution. The concentrations of elements in HNO₃ digests of the soils usually accounted for just little or no statistical variability of their soil solution concentrations.     

四川茶区土壤营养元素背景值研究

采用单道扫描等离子发射光谱仪(ICP-AES)对四川茶区72个产茶县422个取样点035.cm土层中P、S、K等17种营养元素含量进行测定,分析了该地区茶园土壤的无机营养元素背景值特征。结果表明,四川茶区土壤中P、K、Ca、Mg、S等5种大、中量元素均相对贫乏;微量元素Mn、B、Zn在大部分地区土壤中相对富集,而Fe、Mo在大部分地区土壤相对贫乏;其他元素中Se和Sb相对富集,其浓集系数K值分别为5.45和22.3。方差分析表明,17种营养元素的含量在不同产茶地区土壤中的差异均显著。土壤中营养元素的背景值因土壤类型的不同而表现出一定的差异,其中棕壤中的营养元素含量相对丰富,而红壤中营养元素的含量相对缺乏。因此应有针对性地增施有机肥及微量元素肥料,以补充相对贫乏的营养元素。     

中国某些土壤中的水溶性稀土元素

Water-soluble rare earth elements (WSREEs) of four typical soil profiles in China were determined by using a high-resolution inductively coupled plasma mass spectrometer. Results showed that the contents of WSREEs decreased from upper layer to lower layer of soils in the southern part of China with a high rainfall and low pH but increased for soils in the northern part of China with a low rainfall and relatively higher pH. Contents of WSREEs in soils were lower than 100 μg kg^-1 in most cases, and varied greatly with both different soils and different layers of the same profile. The highest content was 2816.3 μg kg^-1 but the lowest was 17.6 μg kg^-1 only. The content of individual rare earth lement (REE) in the soil solution also varied greatly with the highest one ranging from 8.4 to 1373 μg kg^-1 for Ce and the lowest one from 0.05 to 4.48 μg kg^-1 for Lu. The sum of WSREEs in the first soil layers ranged from 121.5 to 345.6 μg kg^-1. Great variations existed among ratios of REEs extracted with water to the total REEs of soils, ranging from 0.02×10^-3 to 13.2×10^-3. But as the upper layer was considered, the ratio showed only a small difference, ranging from 0.79×10^-3 to 1.69×10^-3.     

Determination of N-nitrosodimethylamine levels in some Canadian 2,4-D amine formulations

Levels of N-nitrosodimethylamine (NDMA) were determined in 112 samples of 2,4-dichlorophenoxyacetic acid, (2,4-D), formulated as the dimethylamine salt, collected over a 2 year period from products on the Canadian market. A sample aliquot is partitioned with dichloromethane, and the co-extracted dimethylamine is removed by cleanup on a silica gel column. The eluates containing NDMA are concentrated, an internal standard of N-nitrosodipropylamine is added, and nitrosamine levels are determined using a gas chromatograph interfaced with a thermal energy analyzer. Recoveries of NDMA and N-nitrosodiethylamine spiked into samples were 103 +/- 16 and 96.3 +/- 9.8%, respectively. Of the 112 samples analyzed, 92 were below 1 part per million (ppm) relative to the amount of 2,4-D in the samples, 16 were between 1 and 5 ppm, and 4 were greater than 5 ppm. The gas chromatographic column used is compared to a conventional packing material for volatile nitrosamine analysis. Formation of NDMA during cleanup and analysis was shown not to occur.     

Distribution of some elements in soils of the Barada River bank in Syria

Abstract

The distribution of zinc (Zn), copper (Cu), lead (Pb), and arsenic (As) in a soil of the Barada River bank in eastern Damascus, Syria, was studied. The results showed a normal distribution of these elements with some anomalies. The mineralogical and physical studies did not reveal any changes, indicating that elemental anomalies were man made.     

Distribution of elements in some Fe-Mn nodules and an iron-pan in some gley soils of New Zealand

Three soil nodules and an iron-pan have been analysed for the elements Al, Si, Ti, V, Mn, Fe, Co, Ni, Cu and Zn using an electron microprobe. From the surface analysis it appears that the nodules consist of two major concentration zones of enrichment, viz. Mn-rich, Fe-rich zones and a third zone low in Mn and Fe. The elements Co, Ni, Cu and Zn are enriched in the first zone, whereas vanadium is enriched in the second zone. Four concentration zones are distinguishable in the iron-pan, Ti-rich, Fe-rich, Ti and Fe-rich and a zone low in Ti and Fe. The metals Mn, Co, Ni, Cu and Zn are mainly enriched in the Ti/Fe-rich zone. The associations of the trace elements with the major components of the nodules and iron pan are discussed in terms of physico-chemical factors.     

Properties and distribution of iron oxides and their association with minor elements in the soils of south-western Australia

Iron oxides from 39 soils derived from various parent materials in south-western Australia have been studied using a variety of techniques. Goethite and hematite were the only two Fe oxides present. The goethite/(goethite+hematite) ratio ranged from 0.18 to 1.0, and was highest in soils on acidic igneous rocks, decreasing for soils on alluvial and mafic parent materials. In a few soils derived from acid rocks only goethite was present. The redness rating of soils increased linearly with increasing amount of hematite. Al substitution in goethite ranged from 13 to 35 mol%, with higher values for soils on acid igneous rocks (median value = 26 mol%) than for soils on mafic (19 mol%) and alluvial (17 mol%) parent materials. Substitution of A1 in hematite ranged from 4 to 23 mol%, and was greatest in soils on mafic parent materials (median value = 12 mol% A1). A1 substitution in hematite was about half of that in associated goethite. The dehydroxylation temperature for goethite increased linearly with increasing A1 substitution. Goethite and hematite had similar crystal sizes (c. 20 nm), and both were in the form of irregular plates. Dissolution with 1 M HCl of iron oxides concentrated from the soils by 5 M NaOH digestion could be described both by the Cube Root Law and by Kabai's equation. Only one straight line was obtained for the dissolution data using Kabai's equation for samples containing both goethite and hematite, in contrast to the results of other workers. Major proportions of the Co, Cr, Cu, Mn, Ni and Zn in the soils were concentrated with the iron oxides, and the dissolution kinetics of these elements indicate that some may be present in the structure of the iron oxides.     

杭州市城市土壤中重金属、磷和其它元素的特征

Health implications of inhaling and/or ingesting dust particles with high concentrations of heavy metals from urban soils 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 82 locations in Hangzhou City were measured to: a) assess their distribution in urban environments; and b) understand their differentiation as related to land use. Metal mobility was also studied using a three-step sequential chemical fractionation procedure. 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 commercial and industrial areas, most samples had metal concentrations below their allowable limits. Statistical analyses revealed that the 16 measured elements in urban soils could be divided into four groups based on natural or anthropic sources using a hierarchical cluster analysis. Additionally, Cu, Pb, and P showed similar spatial distributions with significant pollution 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 were the main sources of these seven metals. Moreover, the data highlighted land-use as a major influence on heavy metal concentrations and forms found in topsoils with large proportions of soil Cd, Co, Cr, and Ni found in residual fractions and soil Cu, Pb and Zn mainly as extractable fractions.     

Trace elements in Bangladesh paddy soils

Abstract

A study was carried out to investigate the status of four micronutrients, iron (Fe), copper (Cu), manganese (Mn), and zinc (Zn), and five other trace elements, cobalt (Co), chromium (Cr), nickel (Ni), lead (Pb), and strontium (Sr), in paddy soils of Bangladesh. Soil samples were digested by hydrofluoric acid (HF)‐nitric acid (HNO₃)‐perchloric acid (HClO₄) for determination of total contents of the nine elements, while DTPA, ASI and 0.1 Mhydrochloric acid (HC1) methods were used for determination of available Fe, Cu, Mn, and Zn. Total trace element contents were found to vary with physiography on which soils are distributed. In general, Ganges Tidal Floodplain soils had the highest content, whereas terrace soils had the lower content. Among the soil properties examined, clay content had a good relation with total trace element contents in the topsoil, except for Sr. Based on the variation with physiography or clay content, the nine trace elements could be grouped into six groups: Cu, Fe and Zn, Pb, Co and Cr and Ni, Mn, Sr. According to the extractable levels of four micronutrients, Bangladesh paddy soils had the medium to optimum amounts of Fe and Cu, but were deficient sporadically in Mn and extensively in Zn. It was indicated that paddy soils of Bangladesh are yet to be polluted with heavy metals.     

Imogolite in some ando soils

It was reported in a preceding paper⁷⁾ that the Ando soils from Uemura, Choyo, and Kawanishi contained an unknown mineral colloid which was distinctly different in some respects from coexisting allophane. In the Uemura soil, this clay fraction made up more than 20 per cent of the total clay and more than 6 per cent of the soil⁷⁾.     

Trace elements in tropical Asian paddy soils

Attempts were made to evaluate correlations of total trace elements with various soil characters in the hope that such correlations would allow prediction of the trace element status of paddy soils in Tropical Asia.

Among the 11 trace elements studied, Ni and Cr showed by far the highest correlation, followed by the pairs of V and Zn, Ni and Zn, and Cr and Zn.

High positive correlations of trace elements with soil characters were found for the following pairs: total Fe₂O³, and V and Zn, total K₂0 and Rb, total CaO and Sr, total TiO₂, and V, total Al₂0³ and Zn, 10 Å clay content and Rb, clay and V, and sand and Zr. Among the negative correlations, the highest was between total SiO₂ and V, followed by those between total SiO₂ and Zn and sand and Zn.

Soil material classes and inherent potentiality ratings previously established were found to have some value for the prediction of the status of certain trace elements in soil.     

Urease activity in some Trinidad soils

The effects of urea concentration, soil moisture content, period of storage of soil samples, temperature and toluene on the urease activity of fifteen Trinidad soils were investigated. From the multiple regression analysis of clay content, organic carbon, CEC and amorphous Fe and Al and the urease activity of the soils, it was found that the urease activity in the presence of toluene was largely associated with the clay-organic matter complex whereas in the absence of toluene it was associated with the organic matter of the soils.     

Phosphate fractions in some tanzania soils

Inorganic-P fractions were determined in 17 soil profiles from eight soil orders widely occurring in Tanzania. Most of the inorganic-P fractions decreased with depth. Where soils were young, or calcareous, or the parent material rich in phosphorus-bearing minerals, Ca-P was the dominant inorganic-phosphorus fraction. Where the soils were highly weathered, Al-P and Fe-P were the dominant fractions.     

Fixed ammonium in some Bangladesh soils

Nitrogen is the most deficient element and the most limiting factor for crop production in Bangladesh. The total N content in Bangladesh soils ranges between 0.02 and 0.12% (Ahsan and Karim 1988). The low N content indicates the presence of a small organic N pool and suggests that inorganic N plays an important role as a N source for crops. Contribution of “fixed” or “nonexchangeable” NH₄ ⁺ to the N economy of soil has been reported for many tropical soils (Rodrigues 1954; Moore and Ayeke 1965; Dalal 1977; Sahrawat 1995). However, there are few reports on fixed NH₄ ⁺ status in Bangladesh. In the present study, therefore, attempts were made to collect data on fixed NH₄ ⁺ of some major soil series from the important physiographic units of Bangladesh.     

Urea transformation in some tropical soils

The effects of incubation at 20°, 30° and 40°C and urea concentrations of 0, 50, 100 and 200 μg N/g soil on urea hydrolysis and nitrification were investigated in three Nigerian soils. At constant temperature urea hydrolysis and rate of NO₃^? accumulation increased with increasing rate of urea addition. Urea was rapidly hydrolyzed within 1 week of incubation. Nitrification in Apomu soil increased with increasing incubation temperature. Nitrification was slow in acid Nkpologu soil (pH 4.7). Texture, cation exchange capacity and C:N ratios of the soils were not related to urea hydrolysis or nitrification. Nitrite accumulation in these soils was insignificant. Soil pH was decreased by nitrification of hydrolyzed urea-N.     

Saccharides in some Japanese paddy soils

Monosaccharides released by acid hydrolysis from paddy field soil, from the light and the heavy fraction of soil, front some plant fragment were determined using automated anio-exchange chromatography.

Between 5 and 12 per cent of the organic carbon was present as saccharides.

The monosaccharide composition of the different soils was very similar, in spite of differences in the absolute amount of saccharides present. The amount of the various monosaccharide in the whole soil was found to be in the order glucose»xylose galactose, mannose, arabinose rhamnose ribose.

The monoccharide composition of the soils showed a marked contrast to that of the rice ra8ment, and partially decomposed plant remains taken from the soil. Glucose, xylose, arabi-the predominant saccharides in the rice fragments and the plant remains, while the amounts of galactose, mannose, rhamnose were negligibly small.

It was found that the proportion of galactose, mannose, rhamnose and ribose in the heavy fraction Of soil was greater than that of glucose, xylose, and arabinose

The present observation was in agreement with the view that soil sauharides comprised Pentoses originates in plant materials.

The molar ratio of xylose to mannose was calculated to show the characteristics of the mono-saccharide composition of soils and some plant muerials.     

Effects of trace elements on urease activity in soils

Disposal of sewage sludges and effluents on agricultural land is becoming a widespread practice. Most sludge samples disposed on soils contain large quantities of various trace elements. Studies of 20 trace elements commonly found in sludge samples showed that they inhibit the activity of urease in soils and that their order of effectiveness as inhibitors of urease depends on the soil. When the trace elements were compared by using 5 μmiol·g^?1 soil, however, some of them showed the same order of effectiveness as urease inhibitors in the six soils studied i.e., for the monovalent and divalent ions, Ag⁺ ≥ Hg²⁺ >Cu²⁺ >Cd²⁺ >Zn²⁺ >Sn²⁺ >Mn²⁺, and generally, Fe²⁺ >Fe²⁺andCu²⁺ >Cu⁺. Other trace element ions that inhibited urease were Ni²⁺, Co²⁺, Pb²⁺, Ba²⁺, As³⁺ B³⁺, Cr³⁺, Al³⁺. V⁴⁺ Se⁴⁺ and Mo⁶⁺. Of the trace element ions studied, only As⁵⁺ and W⁶⁺ did not inhibit urease activity in soils.Studies on the distribution of urease activity showed that it is concentrated in surface soils and decreases with depth. Urease activity was proportional to organic C distribution in each soil profile and was significantly correlated with organic C in the surface soils studied.