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Understanding soil fertility, influenced by macronutrients such as nitrogen, phosphorus, and potassium, is essential for the implementation of adaptive agriculture based on various soil conditions. Near-infrared spectroscopy technology provides non-destructive, rapid soil property measurements without chemicals, and is applicable both in the field and in the laboratory. However, the wide NIR spectrum range and neural network complexities can hinder Artificial Neural Network (ANN) training and inference, leading to time and resource inefficiency, particularly without sophisticated computing devices. This study examined data reduction methods to enhance ANN performance in predicting soil macronutrients using NIR spectra. Multiple Linear Regression (MLR) and Principal Component Analysis (PCA) were applied to select wavelengths from the 1000–2500 nm for ANN input, comparing their performance. Approximately 237 NIR reflectance data points from paddy soils were transformed into absorbance data. MLR used forward selection to identify wavelengths with correlations higher than 0.9, whereas PCA selected wavelengths corresponding to the loading factor peaks for each principal component. These selected wavelengths served as inputs for the ANN model. The ANN performance was assessed using the correlation and determination coefficients, RMSE, RPD, and model consistency. For nitrogen, the PCA+ANN model with reflectance spectra performed better (RPD 2.4-4.8) than the MLR+ANN model (RPD 2.2-2.6) using fewer wavelengths (5-9 for PCA+ANN vs. 9-12 for MLR+ANN). For phosphorus estimation, the PCA+ANN model also excelled (RPD 2.3-7.0 vs. 2.3-2.4) with fewer wavelengths (4-7 vs. 7). The PCA+ANN model showed superior performance (RPD 4.3-9.5 vs. 4.2-4.4), using the same number of wavelengths (4-8 vs. 4-6). [ABSTRACT FROM AUTHOR]

Inadequate waste management and illegal trash dumping continue to be the leading causes of severe environmental pollution. Human exposure to harmful heavy metals has emerged as a serious health concern on the continent. Some people in Alice, a small town, grow their food in home gardens. They use animal manure and compost derived from soil obtained from landfills to enhance the fertility of the garden soil. Heavy metal heaps in garbage disposals are constantly present, releasing dangerous amounts of metal into the environment. The harmful effects of heavy metals on plants lead to unsanitary conditions and environmental problems. Animals and people who consume these vegetables may also be at risk for health problems. Assessing the soil's enzyme activity can potentially lessen the negative effects of the accumulated pollutants and improve the soil's overall health and quality. Soil enzymes are biologically active components that have a catalytic impact and are released from root exudates, crop residues, and animal remains. The activity of enzymes serves as an excellent bioindicator of soil cleanliness and quality because they are sensitive to heavy metals. X-ray diffraction (XRD) was used to quantify the mineral elements in soil using 40 kV parallel beam optics, 30 mA, and CuKα radiation. Meanwhile, the activity of the enzyme was essayed in different coupled substrates. Thirteen (13) clay minerals were found, including Talc 2M, Kaolinite 2M, and Chlorite Lawsonite Muscovite 2M1. The detected trace elements have high concentration levels that exceed the World Health Organization's (WHO) allowed levels. The identified elements affected the enzyme activity at different levels. The Mn, Al, Si, V, Ti, and Ca negatively affect soil enzyme activity, specifically invertase (INV). However, the amount of Mg, K, Fe, and Zn showed a slightly positive effect on the same enzyme (INV). According to this view, these elements come from several sources, each with a particular impact on soil contamination and enzyme activity. High levels of heavy metals in this study may be due to improper waste disposal, limited recycling opportunities, lack of public awareness, and inadequate enforcement of waste management regulations. It is essential to employ Fourth Industrial Revolution (4IR) technologies, correct disposal techniques, suitable agricultural methods, preventive regulations, and efficient waste management to mitigate the negative effects of heavy metals on the environment. [ABSTRACT FROM AUTHOR]

This article presents the findings of a field experiment conducted in West Bengal to study the growth, yield, and water use efficiency of grass pea under different nutrient management practices. The results showed that fertilizing the grass pea plot with the recommended dose of fertilizer along with foliar application of Borax resulted in the highest plant height, number of branches, dry matter accumulation, number of pods per plant, pod length, number of seeds per pod, and 100-seed weight. The plot treated with RDF+ Borax also recorded the highest seed yield, stover yield, and water use efficiency. The study concludes that the combined use of RDF with Borax is the best option for better production of grass pea in terms of quality and quantity in the New Alluvial Zone of West Bengal. [Extracted from the article]

The development of suitability species models look for the availability to growth in a study area. These models can be used for different targets. In this research, a suitability model of Eucalyptus has been developed to soils contaminated by trace elements management. Guadiamar Green Corridor has been selected due to the huge data available regarding trace elements, forestry species and so on. Logistic regression (LR) and Random Forest (RF), as popular machine learning model, were applied in a geodatabase from Guadiamar Green Corridor with more of 20 years of data. This database is composed by soil physical and chemical variables, climate (temperature min and max, annual precipitation), forestry species. The results show the poor performance of LR and RF applied directly over the unbalanced training set. However, when Upsampling or SMOTE are applied, both procedures improve its sensitivity, however, RF show more improve that LR. The methodology applied can help to determine the potential distribution of Eucalyptus in similar Mediterranean areas and extended to different areas according to Soil, Climate and Trace Elements data. Finally, the models developed under this research work can be used to reduce human and environmental health by trace elements taking into account local conditions but also climate change scenarios. [ABSTRACT FROM AUTHOR]

Urban areas are the hot-spots of soil pollution, as a result of increase in urban populations, vehicular transport increase and industrial growth. Due to the rapid growth of urbanization, urban soil contamination by potentially toxic trace elements (PTEs) has become one of the major public health and environmental concern. This research assessed PTEs (As, Cd, Pb, Cr, Cu, Co, Mn, Zn, and Ni) concentrations in urban soils from the Kermanshah urban areas in western Iran. Thirty soil samples were collected from residential urban parks, as from depth of 0––20 cm. Concentrations of PTEs in the soil were determined by ICP-OES. Multivariate analysis method was applied to distinguish the anthropogenic and natural sources of PTEs. Also geostatistics and geographical information system (GIS) were applied to produce spatial distribution patterns. The contamination degree of PTEs was assessed on the basis of geoaccumulation index (Igeo), the Enrichment factor (EF), single pollution index (Pi) and Nemerow pollution index (PINemerow). Applying principal component analysis (PCA), three components were extracted. The first principal component with a high loading for Mn, Co, Cd, Cu, and As, the second principal component, with high contribution of Cr, Ni and Pb and the third component having strong loadings of Zn. Mn, Co, Cd, Cu, and As may be defined as an anthropogenic, Cr, Ni and Pb reflect the contribution of natural and anthropogenic sources and Zn was mostly controlled by natural sources. The results of Pi were consistent with PCA. Spatial distributions showed that that the higher Pb concentration was concentrated mostly in the central and south parts of the city and higher Cd in the east parts of the study area. The map of As indicated maximum concentration in the north and west parts of the study area. Similar trends of spatial distributions between Cu and Zn, between Cr, Ni, and between Co and Mn were observed. The metal concentrations indicated that the Kermanshah city is threatened by PTEs associated with anthropogenic activities specially traffic. [ABSTRACT FROM AUTHOR]

Public recreation areas in cities may be constructed on land which has been contaminated by various processes over the history of urbanisation. Charles Veryard and Smith's Lake Reserves are adjacent parklands in Perth, Western Australia with a history of horticulture, waste disposal and other potential sources of contamination. Surface soil and soil profiles in the Reserves were sampled systematically and analysed for multiple major and trace elements. Spatial analysis was performed using interpolation and Local Moran's I to define geochemical zones which were confirmed by means comparison and principal components analyses. The degree of contamination of surface soil in the Reserves with As, Cr, Cu, Ni, Pb, and Zn was low. Greater concentrations of As, Cu, Pb, and Zn were present at depth in some soil profiles, probably related to historical waste disposal in the Reserves. The results show distinct advantages to using spatial statistics at the site investigation scale, and for measuring multiple elements not just potential contaminants. [ABSTRACT FROM AUTHOR]

Trace metal concentration in soils of Iyara area of Warri, Delta State was studied using geophysical and geochemical techniques. Eight vertical electrical sounding (VES) using SAS 1000 Terrameter with maximum current electrode spread of 150 m in the Schlumberger configuration was carried out. The geoelectric layers obtained are topsoil, clay, sand and fine-medium grained sand. The fine to medium grained sand of the third and fourth layers mainly constitute the aquifer with a depth ranging from 4.8 - 11.0 m. Soil samples were collected at three of the VES stations covering the dumpsite and stations away from the dumpsite. The trace metal content was higher than the maximum allowable levels in soils as specified by the World Health Organisation (WHO) and Department of Petroleum Resources of Nigeria (DPR) except for Pb with undetected concentration in VES 3, Mn with 135 mg/kg in VES 1 and undetected in VES 3 and VES 7. The Multiple pollution index, Enrichment factor, and Non-carcinogenic hazard decreases with increasing distance from the dumpsite. The soil around the dumpsite has been impacted and the results of this study will serve as background information for soil studies and groundwater development in the area. [ABSTRACT FROM AUTHOR]

The Gemer region (Slovakia) belongs to areas with a high concentration of risk elements. The contents of Cu, Ni, Pb, Cd, Hg and Mn were determined in soils and cultivated agricultural production from lands in three cadastres of the Gemer region (Henckovce (48.713845, 20.426189) and Nižná Slaná (48.717373, 20.4208423), cultivated crop—spring triticale; Gemerská Poloma (48.704523, 20.487645), cultivated crop—maize). Bioavailable forms of Pb (0.306–0.532 mg/kg) and Cd (0.104–0.154 mg/kg), pseudototal forms of Cd (3.07–3.98 mg/kg) and Hg (0.484–2.18 mg/kg) represented the highest risk in soils. The highest contents of Pb (Cd, Hg) were in maize from Gemerská Poloma: 0.898 (0.081, 0.399) mg/kg DM. Soils were classified based on several indicators of soil contamination. The highest values of indicators are: Contamination factor (Cf 29.1—Hg), Degree of contamination (Cdeg 51.5), Potential ecological risk factor (Er 1163—Hg), Potential ecological risk index (RI 1,520), Pollution load index (PLI 4.76), Geo-accumulation index (Igeo 5.60—Hg). All indicators concerned the lands of Henckovce and Gemerská Poloma, RI also concerned the land of Nižná Slaná. Bioaccumulation factor (BAF) was calculated to assess the plant's ability to absorb the risk element. For both crops and all risk elements, BAF values were < 1. Obtained results indicate heavy metal contamination of soils, therefore monitoring of soils in investigated area is necessary. [ABSTRACT FROM AUTHOR]

BACKGROUND AND OBJECTIVES: Urban farming makes a substantial influence on the household economy of the urban poor especially in developing countries. Urban soil the hot spot of urban farming is a natural sink for contaminants especially the trace elements derived mainly from anthropogenic activities. This study's aim was to quantify the concentrations of selected trace elements (Cr, Mn, Cu, Ni, and Zn) in topsoil (0-20 cm) and subsoil (21-50 cm) and to evaluate whether their concentration vary during dry and rainy season. METHODS: Grid soil sampling method was used to collect soil samples and their total concentration was determined using a portable X-ray Fluorescence Spectrometer. FINDINGS: The study revealed that the topsoil had higher concentration than sub soil. The topsoil concentration in mg/kg were 61.62, 4042.58, 30.82, 43.90 and 456.43 for Cr, Mn, Ni, Cu and Zn respectively. The subsoil concentration in mg/kg were 54.67, 3791.38, 30.32, 27.83 and 370.32 for Cr, Mn, Ni, Cu and Zn respectively. It also noted that concentration of the trace elements was higher during dry season than wet season but not significantly different (P = .05) for all the elements. CONCLUSION: The study recommends that there is need to monitor levels of trace elements investigated in soil to ensure they do not reach detrimental levels. [ABSTRACT FROM AUTHOR]

Fungi play a key role in the functioning of soil in terrestrial ecosystems, and in particular in the remediation of degraded soils. The contribution of fungi to carbon and nutrient cycles, along with their capability to mobilise soil trace elements, is well-known. However, the importance of life history strategy for these functions has not yet been thoroughly studied. This study explored the soil-fungi relationship of two wild edible fungi, the ectomycorrhizal Laccaria laccata and the saprotroph Volvopluteus gloiocephalus. Fruiting bodies and surrounding soils in a mine-spill contaminated area were analysed. Isotope analyses revealed Laccaria laccata fruiting bodies were 15N-enriched when compared to Volvopluteus gloiocephalus, likely due to the transfer of 15N-depleted compounds to their host plant. Moreover, Laccaria laccata fruiting bodies δ13C values were closer to host plant values than surrounding soil, while Volvopluteus gloiocephalus matched the δ13C composition to that of the soil. Fungal species presented high bioaccumulation and concentrations of Cd and Cu in their fruiting bodies. Human consumption of these fruiting bodies may represent a toxicological risk due to their elevated Cd concentrations. [ABSTRACT FROM AUTHOR]

The article is devoted to the estimation of microelements content in soil in of Uzbekistan. It is established that the properties of soil, its sanitary condition and the degree of its pollution may affect the level of morbidity in the population. The data obtained as a result of studies indicate that most of Uzbekistan is a biogeochemical region with a reduced content of iodine, fluorine, iron, copper, cobalt and phosphorus in the soil, high magnesium and calcium content. Relationships have been revealed between the insufficient content of fluorine in water, soil and plants and the development of caries, while the iodine deficiency is endemic goiter in the human body. The content of these chemicals in the soil can be prioritized from a sanitary point of view. [ABSTRACT FROM AUTHOR]

Pollution from potentially toxic trace elements (PTEs) is becoming serious and widespread in farmland soils in China, threatening food security and human health. Few large-scale studies systematically analyzed their temporal-spatial trends over vast spatially elaborate sites. The soil health status of the main grain producing areas was first announced based on a total of 3662 spatially elaborate farmland topsoil sites from the 1980s to the 2000s. Nearly 21.5% of sites were polluted, although only slightly. Pollution from the Cd, Ni, Cu, Zn, and Hg was more serious. Pollution was more extensive in the south than in the north. There was an increasing trend in the PTE concentrations, especially Cd with a growth of 21–25%, and in the proportion of mixed pollution at the sites (19.3%), Cd (21.5%), Pb (3.6%), Zn (5.7%), Cu (7.0%), and Hg (3.1%). Furthermore, temporal variations in severe Cd pollution and mixed-level Hg pollution in the north are severer. This study may provide guidance for policymakers regarding the protection and high-risk area of PTE contamination in the soils. [ABSTRACT FROM AUTHOR]

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Available information about the application of clay minerals (e.g. sepiolite) at nanoscale levels for stabilization of potentially toxic trace elements in soils and wastewaters is very limited. Therefore, this study was carried out to: (i) determine how removal of Pb and Cu from aqueous solutions (containing 150 mg/kg Pb and Cu) differs between microparticles (<10 μm) and nanoparticles (<100 nm) of sepiolite, and (ii) find out the kinetic parameters of Pb and Cu adsorption onto micro- and nano-sized particles of sepiolite. Batch experiments at eleven contact times (5, 10, 20, 30, 60, 120, 240, 480, 720, 1440 and 2880 min) with three replications were conducted and the data were evaluated using pseudo-first order, pseudo-second order, and intraparticle diffusion models. The results indicated that the sorption of Pb and Cu onto both microparticles and nanoparticles of sepiolite follows an increasing trend with contact time, and it is a three-stage process that is well described by the pseudo-second-order kinetic model. Intraparticle diffusion modeling showed that intraparticle diffusion was not the only mechanism that influenced the rate of Pb and Cu uptake by the nano- and microparticles of sepiolite. The maximum adsorptions of Pb and Cu by sepiolite nanoparticles were 34.70 and 24.50 mg g−1, respectively, higher than those of the microparticles (27.17 and 17.10 mg g−1). To identify how the addition of sepiolite nanoparticles (10 and 20 g/kg soil) would function as a soil amendment relative to Pb and Cu pollution, the leaching potential of Pb and Cu was also tested, using distilled water and 1 M NH 4 NO 3 solutions from the two soils with clay loam and sandy loam textures. The results implied that the addition of sepiolite nanoparticles to both the sandy loam and clay loam soils increased their ability to retain Pb and Cu elements in comparison with the control. In both the clay loam and sandy loam soils, the amounts of Pb and Cu leached using the 1 M NH 4 NO 3 solution were significantly higher than those with distilled water. The amounts of metals eluted using 1 M NH 4 NO 3 solution from the sandy loam and clay loam soils treated with 20 g kg−1 nanoparticles of sepiolite were 7.15% and 5.33% for Cu, and 6.44% and 4.55% for Pb, respectively. The results also illustrated that using water and NH 4 NO 3 solutions, the metal extraction yield was greater in the sandy loam soil than in the clay loam soil. The highest amounts of Pb (9.76%) and Cu (9.88%) leached from the soils were observed in the sandy loam soil, using 1 M NH 4 NO 3 solution, but without any addition of sepiolite nanoparticles. In contrast, the clay loam soil leached with water and amended with 20 gkg−1 sepiolite nanoparticles showed the least amount of Pb (3.49%) and Cu (3.93%) in the leachates. In conclusion, sepiolite nanoparticles improved the efficiency of Pb and Cu removal from aqueous solutions and their immobilization in soils with sandy loam and clay loam textures. The findings also emphasize the importance of extracting agents in evaluating the amounts of Pb and Cu leached from the soils. • Pb and Cu adsorption on both microparticles and nanoparticles followed pseudo-second order model. • Nanoparticles were more effective than microparticles to remove Pb and Cu from solutions. • The leached amount of Pb and Cu using NH 4 NO 3 solution was higher than distilled water. • The metal extraction yield was greater in the sandy loam soil than clay loam soil. • In all experiments, the leached amount of Pb was less than Cu. [ABSTRACT FROM AUTHOR]

Element cycling in the terrestrial environment is heavily reliant upon processes that occur in soil solution. Here we present the first application of microdialysis to sample iodine from soil solution. In comparison to conventional soil solution extraction methods such as Rhizon™ samplers, centrifugation, and high-pressure squeezing, microdialysis can passively sample dissolved compounds from soil solution without altering the in-situ speciation of trace elements at realistic soil moisture conditions. In order to assess the suitability of microdialysis for sampling iodine, the permeability factors and effect of perfusion flowrate on I− and IO 3 − recovery was examined in stirred solutions. Furthermore, microdialysis was used to sample native soluble iodine at a range of water contents and iodine-enriched soils to investigate iodine soil dynamics. Total iodine concentrations were measured using ICP-MS. Inorganic species and the molecular weight distribution of organically bound iodine were determined by anion exchange and size exclusion chromatography (SEC) coupled to an ICP-MS, respectively. The most effective recovery rates in stirred solution were observed with the slowest perfusion flowrate yielding 66.2 ± 7.1 and 70.5 ± 7.1% for I− and IO 3 −, respectively. Microdialysis was proven to be capable of sampling dissolved iodine from the soil solution, which accounted for <2.5% of the total soil iodine and speciation followed the sequence: organic-I > I− > IO 3 −. The use of SEC coupled to (i) UV and (ii) ICP-MS analysis provided detail regarding the molecular weight distribution of dissolved org-I compounds. Dissolved org-I was detected with approximate molecular weights between 0.1 and 4.5 kDa. The results in this study show that microdialysis is a suitable technique for sampling dissolved iodine species from soils maintained at realistic moisture contents. In addition, inorganic iodine added to soils was predominately bound with relatively low molecular weight (<4.5 kDa) soluble organic matter. • Microdialysis is a suitable means of sampling dissolved iodine. • Microdialysis is capable of sampling soil solutions at variable moisture contents. • A SEC-ICP-MS method was developed to detect dissolved organic iodine compounds. • Dissolved organic iodine compounds have relatively low molecular weights (<4.5 kDa). [ABSTRACT FROM AUTHOR]

Risk assessment of soils polluted by potentially toxic trace elements generally is a complex procedure that includes many variables and parameters, many of them difficult to assess. The proposed methodological approach is an easier procedure to obtain reasonable security for the potential risk of a soil contaminated by trace elements. This approach can be successfully applied in most of the case studies, avoiding a sometimes flawed risk analysis procedure, which many times leads to an unnecessary declaration of soil pollution, resulting in mandatory and expensive reclamation actions. The protocol supposes that: a) high concentrations of potentially toxic trace elements exceeding generic reference levels are not always a risk to human health, and b) the mobile fractions of potentially toxic trace elements and their bioavailability are the key factors to consider in any sort of risk assessment, when such assessments are needed. The proposal consists of successive steps that ranges from a simple documentation and investigation of available information of the history, present state of the potential polluted site (PPS), mapping and field works to a detailed study that involves determination of local reference values, geoaccumulation factors, soil parameters, mobility, bioavailability, operational speciation, etc. For As, Hg, Cd, and Pb, particular procedures are also proposed. As can be deduced from the proposal, anomalously high concentrations of potentially toxic trace elements in a soil, although they may exceed the generic reference levels, do not always pose a health risk. Thus, risk assessment is only necessary in a very few cases. • Trace elements exceeding soil screening levels not always pose a health risk • Local baseline and bioavailable fraction should be key factors to consider for risk assessment. • The proposed protocol avoids undesirable errors derived from risk analysis methods. • The method allows assessing the potential risk without overestimating the pollution. [ABSTRACT FROM AUTHOR]

In the present study, we assessed the non-carcinogenic and carcinogenic human health risk due to exposure to trace elements in soil and indoor dust in Puchuncaví valley. We also determined the associations between trace element concentration in hair/toenails and the estimated chronic daily intake of trace elements in soil and indoor dust. We found statistically significant association between the trace element concentration in hair/toenails and the estimated chronic daily intake of soil and indoor dust. Indoor dust was more important than soil in terms of human exposure to trace elements in Puchuncaví, due to the high concentration of trace elements on this environmental media and long periods of time that the population spends at their households. With regards to non-carcinogenic risk, we found that there was no health risk associated to soil and indoor dust exposure in the Puchuncaví valley, because none of the hazard quotient values surpassed 1.0. However, carcinogenic risk due to arsenic exposure was above the threshold value of 1.0E-04 in the population of young children (from 1 to 5 years old) in all studied areas, including the control, and in the population of children (from 6 to <18 years old) in the exposed area. Such risk values are classified as unacceptable (US EPA, 2001), requiring some target intervention from the Chilean government. [ABSTRACT FROM AUTHOR]

Purpose: Urbanization is an important process that changes land use pattern and the sustainability of agroecosystems in the urban-rural transition zone. Through intensified anthropogenic activity, urbanization magnifies trace element (TE) inputs into soils and alters the balance of soil element fluxes. This study aims to investigate the effects of urbanization on the spatial dynamics of soil HMs in peri-urban zones and the distinct behaviors of TEs in response to urban sprawl. Materials and methods: An area (15 km × 16 km) in the Chinese northeastern black soil region was selected to represent a typical urban-rural transition feature that received heavy impact by urbanization in last decade. Two hundred topsoil samples were taken from locations dominated by Phaeozem soils and analyzed for total Zn, Cu, As, Pb, Cd, Cr, Ni, and Hg. Principal component analysis (PCA) was used to distinguish the probable sources of TE inputs into the soils. The overall TE pollution of soils was evaluated by the Nemerow comprehensive pollution index. Inverse distance weighting algorithm combined with autocorrelation analysis was used to analyze the spatial patterns of soil TE distribution. Results and discussion: The mean concentrations of the studied TEs, with the exception of Hg and As, were higher than their background values, and their concentrations were always higher in the part closer to the urbanized area. Soil pollution assessment shows that the overall pollution status was moderate, but for Cd and Cu, numerous hotspots were identified due to the overuse of agrochemicals. PCA showed that Cu, Zn, Pb, and Cd as the first component were due to urbanization and agronomic practices, whereas As, Ni, and Cr as a second group were primarily of lithogenic origin, partly due to urbanization, and Hg was related to the atmospheric deposition of industrial waste gas. Conclusions: Increasing urban sprawl in the study area resulted in higher TE concentrations in the southern part of the region than the northern part, confirming the positive effect of urbanization on excessive soil TE accumulation. Although the pollution status was not yet serious, with the current rate of urban growth, arable soils in the peri-urban area will continuously be contaminated and control measures must be taken to prevent the cumulative impact on human health. [ABSTRACT FROM AUTHOR]

In the present investigation, soil nutrient characteristics of three stands were studied. The soil organic matter content showed a hierarchy of Pinus massoniana forest > slope farmland > Eucommia ulmoides plantation> maple-Cinnamomum camphora mixed plantation in horizontal direction. However, with an increasing depth of soil layer, the soil organic matter content showed a decreasing pattern. The soil total nitrogen phosphorus and potassium contents of different vegetation types followed a pattern of Eucommia ulmoides plantation > maple-Cinnamomum camphora mixed plantation > Pinus massoniana forest > slope farmland. In this, the soil total nitrogen and phosphorus content decreased significantly with the increase in soil depths. The soil available nitrogen, potassium and phosphorus content of different vegetation types exhibited a pattern which follows slope farmland > Eucommia ulmoides plantation > maple-Cinnamomum camphora mixed plantation > Pinus massoniana forest. The soil available nitrogen, potassium and phosphorus content decreased with the soil depth increase. The pattern followed for soil trace elements of different vegetation types were Eucommia ulmoides plantation > slope farmland > Pinus massoniana forest > maple-Cinnamomum camphora mixed plantation. The average contents of trace elements in 0-10 and 10-20 cm of soil layer followed a gradation of Fe > Mn > Zn > Pb > Ni > Cu > Cd. 'Grain to Green Program' increased the soil nutrient content of different vegetation types, and soil nutrient content decreased with the soil depth increase. In this study, significant correlations were observed among soil nutrient elements in different vegetation types. [ABSTRACT FROM AUTHOR]

Selenium (Se), a trace element in the soil, is mainly ingested by the human body from the soil-plant system through food chain. Meanwhile, Se in the soil is subjected to geological, geographical environmental factors and soil properties. Therefore, it is essential to study contents and distributions of Se in the soil for developing Se-enriched agricultural products and protecting human health. Jieyang City is one of distinctive agriculture areas of Guangdong Province, China, and the status of soil Se has an important impact on the development of local distinctive agriculture. Based on the above reasons, a total of 1 330 topsoil samples (0-20 cm) and 331 deep soil samples (150-200 cm) were collected systematically from Jieyang City to discuss the distribution, enrichment characteristics and influencing factors (including parent materials, soil types, land using types, soil physicochemical properties and elevation) of soil Se. Results showed that contents of Se in topsoil ranged from 0.02 to 2.01 mg/kg with a geometric mean value of 0.48 mg/kg that was 1.66 times larger than the average Se contents of soil in China. The topsoils of Jieyang City were in the category of Se sufficiency and Se abundance on the whole. According to the spatial distribution derived by the Kriging interpolation, soils of Se abundance were mainly distributed in Puning, Huilai and northern edge of Jieyang City. The Se enrichment area in the topsoil reached 52.03% of Jieyang City, but the spatial distribution was scattered, which may be related to factors such as parent materials and soil types. Strong Se enrichment soils were mainly distributed in the areas of granite and siltstone, while most of the soil which came from quaternary alluvial deposits was not enriched. Analysis of variance showed that different parent materials, soil types and land use patterns had different effects on soil Se contents and enrichment. The main factor affecting Se contents in surface soil of Jieyang City was soil parent materials. The soils which derived from mudstone and tuff were more likely to enrich Se. Among different land use types, farmland had great influences on soil Se content due to long-term agricultural activities. Among different soil types, yellow soil and latosolic red soil were easy to enrich Se due to their high contents of organic matter. Although soil Se content differed among different land use types, it was not obvious that soil Se was affected by human activities in Jieyang City. In addition, the physicochemical properties of soil and altitude were also important factors of leading to Se enrichment in the topsoil of Jieyang City. Regression analysis showed that there was a significantly negative correlation between Se and pH (P<0.01), and Se was significantly positively correlated with TOC (P<0.01), Fe2O3 (P<0.01) and Al2O3 (P<0.01) in the topsoil. Spearman correlation analysis showed that the Se content in the topsoil of Jieyang City had a significantly positive correlation with elevation (P<0.01). The higher elevation, the soil Se was more easily enriched. Thus, in the development process of distinctive agriculture in Jieyang City, it is recommended to rationally use Se-enriched soils, plant Se-enriched crops, and promote the development of local distinctive agriculture in accordance with the principle of adapting to local conditions. [ABSTRACT FROM AUTHOR]

Abstract Information on chemical fertility status and on trace element concentrations for Singapore soils is sparse. In this study, concentration and distribution of nutrients and trace elements in forest soils of Singapore, and the effect of geology on the current conditions of soils, were evaluated. Litter and mineral soil samples (0–10 cm, 10–20 cm, 20–50 cm) were divided into three groups according to geology (sedimentary rocks, Neogene-Quaternary sediments and igneous rocks). Basic soil properties, exchangeable cations including cation exchange capacity (CEC), and pseudototal concentrations of 17 elements including nutrients and potentially toxic elements (PTE; As, Cd, Cu, Cr, Ni, Pb, Zn) were determined. Results showed that the soils of Singapore were acidic (pH 3.7–6.2) and characterised by a low CEC (maximum mean value: 100 mmol c kg−1) and low P concentrations (mean values of 0.28 g kg−1 or less) irrespective of geology. Pseudototal concentrations of PTE were also low, except for As. However, significantly (p < 0.05) higher concentrations of soil organic carbon, total P, base forming elements, exchangeable base cations and PTE (except As and Cd) were found in soils developed on sedimentary rocks and Neogene-Quaternary sediments compared to those developed on igneous rocks. Although total N and S concentrations did not differ significantly between the three geological groups, the differences in nutrient status were more pronounced than in trace element levels across geology. The properties of forest soils, which are mainly unaffected by anthropogenic activities, vary depending on the parent material, i.e. igneous or sedimentary rocks and Neogene-Quaternary sediments. Highlights • A comprehensive data set for Singapore soils with reference to geology is presented. • Geology is particularly important for soil nutrient status. • Trace element concentrations in forest soils are generally low. • Arsenic concentrations are elevated in soils developed on igneous rocks. • These data can be used to assess soil pollution in Singapore. [ABSTRACT FROM AUTHOR]

This study is aimed to investigate the transfer of potentially toxic trace elements from soils to plants grown under the impact of Alaverdi's mining complex and assess the related dietary exposure to local residents. Contamination levels of potentially toxic trace elements (Cu, Ni, Pb, Zn, Hg, As, Cd) in soils and plants were determined and afterwards, transfer factors, estimated daily intakes, target hazard quotients, and hazard indexes were calculated. Some trace elements (Pb, Zn, Cd) exceeded the maximum allowable levels. EDIs of Cu, Ni, Hg for the majority of studied fruits and vegetables exceeded the health-based guideline values. Meanwhile, in case of combined consumption of the studied food items, the estimated cumulative daily intakes exceeded health-based guideline values not only for the aforementioned trace elements but also for Zn in the following sequence: Zn > Hg > Ni > Cu. HI > 1 values highlighted the potential adverse health effects for local population through more than one trace element. Detailed investigations need to be done for the overall assessment of health risks, taking into consideration not only adverse health effects posed by more than one toxic trace element but also through other exposure pathways. [ABSTRACT FROM AUTHOR]

Trees are considered good candidates for phytoremediation of soils contaminated with trace elements (TE), e.g. mine tailings. Using two year-old Tilia cordata plants, we demonstrated the nature and the scale of root architecture, especially root apices, as an indicator of mining sludge toxicity and plant capability to cope with these stress conditions. The novelty of our research is the analysis of the root response to substrate with extremely high concentrations of numerous toxic TE, and the 3D illustration of the disorders in root apex architecture using a clarity technique for confocal microscopy. The analysis demonstrates (1) a marked reduction in the size of the root apex zones (2) the occurrence of vascular tissues abnormally close to the root apex (3) collapse of the internal tissues in many root apices. Simultaneously, at the cellular level we observed some signs of a defensive response - such as a common increase of cell wall (CW) thickness and the formation of local CW thickenings - that enlarge the CW capacity for TE sequestration. However, we also detected harmful effects. Among others, a massive deposition of TE in the middle lamella which caused major damage - probably one of the reasons why the inner tissues of the root apex often collapsed – and the formation of incomplete CWs resulting in the occurrence of extremely large cells. Moreover, many cells of the root apex exhibited degenerated protoplasts. All these alterations indicate the harsh conditions for lime growth and survival and simultaneously, the manifestation of a defensive response. The obtained results allowed us to conclude that analysis of the nature and scale of structural alterations in roots can be useful indicators of plant ability to cope with stress conditions, e.g. in prospect of using the examined plants for reclamation of soils contaminated with TE. Image 1 • Clearing technique excellently documented the nature of root architecture alterations. • Root architecture analysis clearly shows the extremely high toxicity of the substrate. • Mining sludge exposure caused an increase of CW capacity for TE sequestration. • CW thickening occurred not only in the laboratory but also in similar to field conditions. • Presence of incomplete CW indicates a strong cell dysfunction. The nature and scale of alterations in root apex architecture can be considered as an indicator of mining sludge toxicity and the degree of plant resistance to contaminated substrate. [ABSTRACT FROM AUTHOR]

In the present work the content of cadmium, copper, chromium, lead, nickel and zinc in soil samples from a dairy located in surroundings of Sagua electrochemical company was determined by atomic absorption spectroscopy. The levels found in different samples do not exceed the reference limit values: Cd (6.1 mg.kg-1), Co (253.3 mg.kg-1), Cr (4418.3 mg.kg-1), Cu (269.9 mg.kg-1), Ni (3030.8 mg.kg-1), Pb (113.6 mg.kg-1), Zn (260.1 mg.kg-1)) for Cuban soils. Trends in distribution of metals in soils of this dairy is to increase its concentration with depth, being more pronounced for nickel and zinc. [ABSTRACT FROM AUTHOR]

The present study summarizes the results of investigations of the trace element distribution in soils and their uptake by plants of natural habitats on the ultramafic and acidic rocks of the Polar Urals and Chukotka in the Arctic Russia. Concentrations of Fe, Mn, Zn, Cu, Ni, Cr, and Cowere determined by atomic absorption spectrometry in 194 plant species of 30 families and 157 soil samples. Two leaches were used for the soil - 1 M ammonium acetate (exchangeable) and 1 M HNO3 (acid soluble); a mixture of 1.5 M HNO3 and 3.7 M HCl was used for the plants. The levels of Fe, Cr and especially Ni in the soils on the ultramafic rocks exceeded those of soils on the acidic rocks. The mineral composition of plant species varies depending on the differences in chemical and mineralogical composition of the two soil-forming rock types. Taxon-specific features in the accumulation of potentially toxic elements in plants of these regions have been revealed for the first time. The data on the metal accumulation ability of plant species show that the species Thlaspi cochleariforme DC. and Alyssum obovatum (C.A. Mey) Turcz. (Brassicaceae) could be considered as Ni hyperaccumulators. These species could therefore have potential for Ni phytoextraction from contaminated soils. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Gasification biochars showed comparable performance in metal(loid) immobilization to that of pyrolysis biochar. • Biochar amendment affected soil microbial activity and the response of different microbials varied with different biochars. • Parameters from EEM-PARAFAC modeling of soil DOM showed close correlation with soil microbial activity. Abstract Compared to pyrolysis biochar (PBC), gasification biochar (GBC) differs in both composition and surface functionalities due to the use of an oxidizing purging gas. This work compares the effect of using PBC and GBC as soil amendments on the soil properties, trace metal bioavailability, soil microbial activity, and soil dissolved organic matter (DOM). Biochar-driven reduction of bioavailable metals does not necessarily result in a positive impact on the soil microbial growth. The DOM in the soil was strongly related to the soil microbial activity, as revealed by the strong correlation between the soil dehydrogenase activity (DHA) and soil dissolved organic carbon (r = 0.957, p < 0.01). Three identified fluorescent components (C1, C2, C3) in the soil DOM were closely associated with the soil microbial activity, for instance, with a clear positive correlation between the soil DHA and C1 (r = 0.718, p < 0.05) and a significant negative correlation between the total bacterial fatty acid methyl ester content and C3 (r = -0.768, p < 0.05). The bioavailability of Cd and Zn is not only related to the pH and surface functionalities of the biochar, but also to its aromatic carbon and inorganic mineral composition. This study further demonstrates that a fluorescence excitation-emission matrix coupled with parallel factor analysis is a useful tool to monitor changes in the soil quality after application of biochar, which is greatly relevant to the soil biota. [ABSTRACT FROM AUTHOR]

Abstract Playas are common natural occurrences in the Southern High Plains of Texas and act as sources of runoff in rural and urban settings and provide habitat for migratory waterfowl. Rural and urban playas in Lubbock County, TX were geochemically compared in order to optimize management for ecological functionality. Soil texture, specifically sand and clay, and organic matter concentration influenced geochemical properties such as trace element concentration, pH, and electrical conductivity. Rural playas contained more clay, organic matter, trace elements, and electrical conductivity than urban playas. Urban playas had a higher pH and roughly twice the sand content of rural playas. The prevalence of sand in urban playas likely influences groundwater recharge dynamics and potentially disqualifies these lakes as Vertisols owing to their sandy nature. The soil mineralogy between urban and rural playas were also different. Quartz and muscovite were the dominant minerals in urban and rural playas, respectively. The differing soil properties between rural and urban playas signify the necessity of unique management strategies. Highlights • Physicochemical comparisons were made between urban and rural playas. • Urban playas featured higher sand content and pH than rural playas. • Rural playas featured higher organic matter and heavy metals. [ABSTRACT FROM AUTHOR]

Abstract The use of fertilizers and fungicides causes the accumulation of trace elements in vineyard soils that may increase their bioavailability for plants. The aims of this study were to evaluate the cadmium (Cd), copper (Cu), nickel (Ni), and zinc (Zn) accumulation and distribution in three depths of 10 vineyard soils using total content, fractionation and DTPA extraction, and also to measure the content of trace elements in aerial parts of grapevines. The highest contents of Cd, Cu, Ni and Zn were observed at 0–20 cm layer and decreased with the depth. The mean total contents of the trace elements in the surface layer of row and between row soil samples were (mg kg−1) respectively, Cd 2.39, 2.43; Cu 46.63, 44.11; Ni 45.55, 44.30; Zn 100.92, 95.35. The highest percentage of the Cd was associated with carbonate (CARB) fraction, while the greatest percentage of the Cu, Ni and Zn were present in the residual (RES) fraction. Therefore, the Cd may be formed bioavailable and leachable forms in vineyard soils. The mobility factor (MF) values in row soil samples ranged from 39–51, 7–11, 6–10 and 4–10 for Cd, Cu, Ni and Zn, respectively indicating high leachability of Cd. The DTPA-extractable contents of trace elements in the surface layer were higher than those in the subsurface layers. The mean bioavailable contents of trace elements in the surface layer of row and between row soil samples were (mg kg−1) respectively, Cd 0.43, 0.43; Cu 2.19, 2.12; Ni 1.71, 1.71; Zn 2.45, 2.34. The content of trace elements in the leaves was higher than the berries. The mean contents of trace elements in leaves and berries were (mg kg−1) respectively, Cd 0.36, 0.00; Cu 5.91, 5.39; Ni 9.58, 6.27; Zn 27.04, 8.06. Trace element contents showed the following order: Zn > Ni > Cu > Cd in leaves and berries. The transfer factor (TF) values of trace elements in the leaves were higher than the berries and showed the following order: Zn > Ni > Cu > Cd in leaves and Ni > Cu > Zn > Cd in berries. There were significant and positive correlations between total and bioavailable contents of Cd, Cu, Ni and Zn in soils with correlation coefficients 0.97, 0.89, 0.66 and 0.85, respectively. The Cd and Cu contents in the aerial part of plants showed significant and positive correlations with total and bioavailable contents of these trace elements in soils, whereas the Ni and Zn contents in the aerial part of plants correlated significantly and positively only with bioavailable contents of these trace elements in soils. Graphical abstract Unlabelled Image Highlights • The highest content s of Cd, Cu, Ni and Zn were observed at 0–20 cm layer and decreased with the depth. • The Cd formed bioavailable and leachable forms in vineyard soils. • Total and bioavailable contents of Cd, Cu, Ni and Zn correlated positively and significantly in soils. • Trace elements showed the following order: Zn > Ni > Cu > Cd in leaves and berries. [ABSTRACT FROM AUTHOR]

Abstract The objective of this study was to determine the natural concentrations of Hg and Se in 45 representative soil profiles from the Cerrado biome in central Brazil, and to correlate their concentrations with soil chemical and physical characteristics. The study area was composed of three sub-regions: Goiás, Northwest of Minas Gerais, and Minas Gerais Triangle. Selenium and Hg concentrations were determined by acid digestion and atomic absorption spectroscopy. Data were subjected to analysis of variance on the means of the Hg and Se variables within each soil class at two depths, followed by multivariate statistical methods. The Hg concentrations ranged from 15 to 182 μg kg−1 and the Se concentrations ranged from 22 to 72 μg kg−1. The soil characteristics that most contributed to Hg concentrations in the soils, according to principal component analysis, were Fe 2 O 3 , FeO, TiO 2 , pH, P 2 O 5 , and effective CEC. In general, the soils of the Cerrado biome have deficient Se concentrations. The Humic Rhodic Acrustoxes have Hg concentrations above the prevention reference value for soils of Minas Gerais. Highlights • Natural Hg and Se concentrations in Cerrado soils are low. • Concentrations of Hg correlated positively with the main oxides found in tropical soils. • Humic Rhodic Acrustoxes may act as sinks to accumulate Hg. • The soils in this study are considered deficient in Se. [ABSTRACT FROM AUTHOR]

Abstract To understand the distribution of soil elemental concentrations and their potential sources of trace metal contamination in the high-conservation Nee Soon freshwater swamp forest in Singapore, we analyzed samples from 227 surface and 35 subsurface (auger profiles) locations. Our assessment involved distribution maps, principle component analysis, cluster analysis, and correlation analysis of element concentrations determined from a mixed acid digestion and measurement on an ICP-MS. We found a distinct zonation in the distribution of several elements (Ba, Cr, Cu, Fe, Mn, Pb, Sr, Ti, V, and Zn) between the upper and lower catchment that gives an erroneous notion of widespread contamination in the lower catchment. We believe this zonation is natural, likely related to differences in the underlying geology. However, Cu, Pb, and Sb concentrations were greatly enriched by anthropogenic activities on military training lands in the lower catchment, firing ranges in particular. Barium, Sr, and Zn also appear to be enriched in the lower part of the catchment, possibly from anthropogenic activities including military activity and roads. Although soils in the catchment are not highly contaminated, isolated areas with high concentrations of Cu, Pb and Sb may warrant management attention given the sensitive nature of the urban forest, which includes the last remaining fresh water swamp forest in Singapore. Highlights • Elemental zonation is naturally related to zonation in underlying bedrock. • Anthropogenic activities produce hotspots of high concentrations of heavy metals. • Potential heavy metal contaminants are not being mobilized from disturbed lands. • High concentrations of Cu, Pb and Sb are generated by activities on military lands. [ABSTRACT FROM AUTHOR]

The orogenic peridotites and pyroxenites of the Ulten Zone (north Italy) record multistage metasomatism by crust-derived melts and fluids within a Late-Variscan mantle wedge. We acquired new major and trace element data as well as garnet and whole-rock iron speciation for a representative suite of samples, with the aim to further constrain element cycling and the redox state attending the development of the major mineralogical and textural rock types that occur within the Ulten Zone. Initially, spinel peridotites were refertilized by mafic melts in the hot and shallow mantle wedge, followed by garnet formation as the peridotites were carried towards a cool, subducting slab of continental crust by corner flow. Upon exhumation, ingress of aqueous, crust-derived fluids provoked amphibole-forming reactions, which caused gradual consumption of garnet and clinopyroxene and transformation from coarse- to fine-grained assemblages. Since Si, Al, Na, Ti, Ca and HREE formerly stored in reactants were not fully accommodated in newly-formed phases, these elements were partially removed from the bulk-rock, generating more depleted compositions resembling residues after partial melting. Unexpectedly, the remaining garnet retains low Fe3+/ΣFe (<0·046) even after the bulk-rocks became strongly enriched in Fe3+ during metasomatism and retrogression (Fe3+/ΣFe = 0·11–0·23), which was mostly stored in coexistent amphibole and interstitial serpentine. Low Fe3+/ΣFe in garnet is consistent with Δlog f O2 = FMQ-1·7 to FMQ-0·3 at 2 GPa. Combined with previous studies, this is evidence for garnet growth within a heterogeneously oxidized mantle wedge, reflecting a variable extent of percolation by oxidizing aqueous fluids. During metasomatism, concomitant variable enrichment in LILE, LREE and some HFSE, and significant compositional differences between sampling localities, reflect both variable fluid/rock ratios at small spatial scales but also indicate chromatographic effects that likely relate to different positions relative to the subducting crust releasing fluids into the mantle wedge. Hydration by dilute fluids during retrogression did not result in additional enrichment in fluid-mobile elements, but caused further replacement of garnet and clinopyroxene. This study highlights the control that changing mineralogies, developed in response to interaction with various crustal melts and fluids under variable pressure-temperature and redox conditions in a continental subduction zone, exert on the retention or release of major and trace elements in peridotite. In particular, formation and/or persistence of amphibole and dolomite, as documented in the present study, suggest that the subduction-modified mantle wedge is an efficient trap for volatiles and fluid-mobile elements. [ABSTRACT FROM AUTHOR]

Abstract The chemical stabilization, or immobilization, of trace elements (metals and metalloids; TE) in contaminated soil has been studied for decades. A vast number of scientific publications are available on the method performance in laboratory settings, reporting that the application of various soil amendments to contaminated soil reduces TE mobility, bioavailability and toxicity. The most commonly used soil amendments include organic matter, iron oxides, phosphates, ashes, and lately biochar, alone or in combination with each other and/or lime. Most of the implemented field studies show a certain degree of improvement in soil and/or vegetation status following amendment. Regardless the positive performance of the technique in the laboratory, field validations and demonstrations remain scarce. The establishment of a field experiment often involves permits from authorities and agreements with site owners, both of which are considerably more time-consuming than laboratory tests. Due to conservative institutional structures, public authorities have been slow to adopt alternative remediation technologies, especially when the total TE concentration in soil remains the same and all of the associated risks are not yet convincingly described. For this reason, researchers should also focus on enhancing public knowledge of alternative remediation techniques so that future projects which aim to demonstrate the effectiveness of in situ immobilization techniques under natural conditions will be supported. Graphical abstract Image 1 Highlights • Vast body of literature is available on TE immobilization in contaminated soil studied at laboratory scale. • Ca 50 published field studies of the technique demonstration/validation in field were found. • Most of the field studies show a certain improvement in the soil and/or vegetation status. • Institutional barriers contribute to the slow transition from laboratory to field demonstrations. [ABSTRACT FROM AUTHOR]

Abstract Rapidly detecting trace levels of organic contaminants in complex mediums is a great challenge for mass spectrometry analysis. Especially in dealing with large quantities of soil samples, the laborious sample pretreatment process is exhausting and time consuming. Here, a simple method for quickly identifying and quantifying tetrabromobisphenol A (TBBPA) in soils and sediments has been developed via paper spray ambient mass spectrometry coupled with a stable isotope internal standard technique in this study. The soil and sediment extracts, spiked with a certain amount of 13C 12 -TBBPA (Ring-13C 12), are directly loaded and separated on chromatographic paper, sprayed and ionized by a high negative voltage, and ultimately analyzed by mass spectrometry without purification and chromatography separation processes. Data acquisition for each test can be finished within 1 min. In the quantification of TBBPA, a linear range of 0.1–100 µg L–1, a limit of detection of 0.039 µg L–1 and a relative standard deviation (c = 1.0 µg L–1, n = 5) of 5.3% are obtained. The spiking recoveries range from 90.4% to 101.1% for analyzing ten soil and sediment samples (0.012–30.14 µg g–1 dw), suggesting that the method should be a promising strategy for rapidly detecting organic pollutants in soils and sediments. Graphical abstract A simple method for quickly identifying and quantifying tetrabromobisphenol A (TBBPA) in soils and sediments has been developed via paper spray ambient mass spectrometry coupled with a stable isotope internal standard technique. fx1 Highlights • Tetrabromobisphenol A in soils and sediments can be rapidly and precisely detected. • Purification and chromatography separation processes are not needed. • As low as 0.039 µg L–1 of TBBPA (limit of detection) can be detected. • High-throughput analysis of soil and sediment samples is achieved. [ABSTRACT FROM AUTHOR]

The aim of the study was to determine the effect of increasing doses of cobalt (0, 20, 40, 80, 160, 320 mg/kg d.m. of soil) on the total content of trace elements in soil after application of manure, clay, charcoal, zeolite and calcium oxide. The neutralizing substances were applied at 2% of the soil weight, and calcium oxide at a dose corresponding to one hydrolytic acidity. The content of the cobalt, cadmium, lead, chromium, nickel, zinc, copper, manganese and iron was determined in soil. The contamination of soil with cobalt and the application of neutralizing substances had significant effects on the total content of trace elements in soil In the series without substances, the soil contamination with cobalt increased the content of cobalt, lead, chromium, nickel and zinc in soil. All the neutralizing substances reduced the content of cobalt, manganese and iron in soil. The highest decrease in the cobalt content was observed in the series with manure, whereas the highest decrease in zinc occurred after addition of charcoal. The decrease in the content of the other metals (except nickel and lead) was observed in the pots with CaO and zeolite. The effect of other neutralizing substances depended on the trace element. [ABSTRACT FROM AUTHOR]

Halogens are primarily located within surface reservoirs of the Earth; as such they have proven to be effective tracers for the identification of subducted volatiles within the mantle. Subducting lithologies exhibit a wide variety of halogen compositions, yet the mantle maintains a fairly uniform signature, suggesting halogens may be homogenized during subduction to the mantle or during eruption. Here we present halogen (Cl, Br, and I), K, noble gas, and major and trace element data on olivines from three seamounts along the Hawaiian‐Emperor seamount chain to determine if the deep mantle source has retained evidence of halogen heterogeneities introduced through subduction. High Ni contents indicate that the Hawaiian‐Emperor mantle source contains a recycled oceanic crust component in the form of pyroxenite, which increases from the 46% in the oldest (Detroit) to 70% in the younger seamount (Koko). Detroit seamount retains mid‐ocean ridge basalts (MORB)‐like Br/Cl and I/Cl, while the Br/Cl and I/Cl of Suiko and Koko seamounts are higher than MORB and similar to altered oceanic crust and dehydrated serpentinite. Helium isotopes show a similar evolution, from MORB‐like values at Detroit seamount toward higher values at Suiko and Koko seamounts. The correlation between pyroxenite contributions, Br/Cl, I/Cl, and 3He/4He indicates that subducted material has been incorporated into the primordial undegassed Hawaiian mantle plume source. The identification of recycled oceanic crustal signatures in both the trace elements and halogens indicates that subduction and dehydration of altered oceanic crust may exert control on the cycling of volatile elements to the deep mantle. Key Points: Trace elements in Emperor seamount olivines indicate magmatism sampled an increasing proportion of pyroxenite through timeHigher than mantle Br/Cl and I/Cl in the younger seamounts indicate that the pyroxenite contains a subducted volatile componentHelium isotope variations indicate that Hawaiian plume magmatism also sampled primitive material derived from the deep mantle [ABSTRACT FROM AUTHOR]

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Abstract Establishment of geochemical background and threshold values of potentially toxic elements is essential for soil management activities. Available topsoil data collected in the Bulgarian soil quality monitoring network are explored for the concentrations of the potentially toxic elements (PTEs) of As, Cd, Cr, Cu, Hg, Ni, Pb and Zn. The ‘median + 2MAD’ and TIF methods for obtaining geochemical threshold values, which differentiate sampling sites with background from those with unusually high element concentrations, are presented. Comparison of the derived national geochemical threshold values with those obtained in European studies outlines the specificity of the Bulgarian PTE background concentrations among the other southern European countries. The threshold values for Cd, Cu, Ni, Pb and Zn are more similar to those derived from the northern European countries since the As and Cr ones are more close to the values derived for southern Europe. The geochemical threshold of Hg is almost one order of magnitude as high as the southern European derived value. The usage of geochemical threshold values for soil risk assessment is suggested by comparison with soil quality guideline values adopted in other countries. The combination of threshold values based on 90th percentile with geochemical mapping identifies the priority areas for further assessment. Regions with more than 2 PTEs (2.26% of the Bulgarian territory) are suggested for detailed (eco)toxicological assessment. Graphical abstract Unlabelled Image Highlights • Determination of geochemical background and threshold values for 8 potentially toxic elements in Bulgarian top soils • Comparison of 2 statistical approaches for the calculation of geochemical threshold values • Identification of priority areas for further assessment based on threshold values and geochemical mapping [ABSTRACT FROM AUTHOR]

Abstract The concentrations of Cd, Cr and Pb in soil samples and As, Cd, Cr and Pb in plant specimens were analyzed in an arid area in central Iran. Plants were categorized into desert-adapted (Haloxylon ammodendron , Atraphaxis spinosa and Artemisia persica) and non-desert species. It was found that the trace element (TE) accumulating potential of the desert species (Haloxylon ammodendron and Artemisia persica) with a mean value of 0.1 mg kg−1 for Cd was significantly higher than that of the majority of the non-desert species with an average of 0.05 mg kg−1. Artemisia also had a high As accumulating capability with a mean level of 0.8 mg kg−1 in comparison with an average of 0.2 mg kg−1 for most of the other plant species. The mean values of Cr and Pb in Haloxylon ammodendron and Artemisia persica were 5 and 3 mg kg−1, respectively. Among the desert-adapted plants, Atraphaxis proved to be a species with high Cr and Pb accumulating potential, as well. The geoaccumulation index and the overall pollution scores indicated that the highest environmental risk was related to Cd. Different statistical analyses were used to study the spatial patterns of soil Cd and their connections with pollution sources. The variogram was estimated using a classical approach (weighted least squares) and was compared with that of the posterior summaries that resulted from the Bayesian technique, which lay within the 95% Bayesian credible quantile intervals (BIC) of posterior parameter distributions. The prediction of cadmium values at un-sampled locations was implemented by multi-Gaussian kriging and sequential Gaussian simulation methods. The prediction maps showed that the region most contaminated by Cd was the north-eastern part of the study area, which was linked to mining activities, while agricultural influence contributed less in this respect. Graphical abstract Image 1 Highlights • Trace element accumulating potential of desert plants was high. • Haloxylon , Atraphaxis and Artemisia genera are potential candidates for phytoremediation. • Mine sites significantly contributed toward detected values of cadmium. • Generated maps of cadmium produced by SGS were more reliable that multi-Gaussian kriging method. [ABSTRACT FROM AUTHOR]

A 15-day batch experiment was conducted to investigate the behaviours of Fe, Mn, and Al oxides upon attack by three common low-molecular-weight organic acids, and their effects on liberation of trace elements from a multi-contaminated soil. While the capacity of malic acid to mobilize soil-borne Fe, Mn, and Al was weaker compared to citric and oxalic acids, a similar trend was observed, showing that the concentration of dissolved Fe, Mn, and Al increased with increasing duration of the experiment. Marked increase in metal concentrations only took place after 5 or 7 days of the experiment. For the same organic acid treatment, Fe, Mn, and Al all showed a very similar temporal variation pattern. The concentration of dissolved Fe, Mn, and Al was markedly controlled by the total Fe, Mn, and Al contained in the soil, respectively. It appears that manganese oxides were more reactive to the organic acids, as compared to their Fe and Al counterparts. However, when multiple organic acids were present, the soil-borne Fe, Mn, and Al were mobilized rapidly within the first 5 or 7 days of the experiment and then tended to decrease. The formation of insoluble Fe, Mn, and Al organic complexes tended to be enhanced due to co-existence of multiple organic acids, resulting in the re-immobilization of the dissolved Fe, Mn, and Al. The organic acid-driven dissolution of Fe, Mn, or Al had a major control on the mobilization of As, Cr, Zn, Ni, Cu, and Cd that were bound to these oxides with a correlation coefficient being frequently greater than 0.9 for As, Cr, Zn, and Ni. [ABSTRACT FROM AUTHOR]

Research was carried out to determine and asses the influence of mining industries on soil contamination with application of various pollution indices. For soil sampling 13 points were selected. Soil samples were analyzed for heavy metals by AAS. Eleven elements were determined and the greater quantities were generally observed in case of Mo and Cu. During the testing of soil pollution level pollution load index, degree of contamination (Cd) and geoaccumulation index were used. The correlation analysis revealed the strongest positive correlation between molybdenum and copper and that the high content of mentioned elements in soil was caused by mining industry. Assessment based on Cd showed that the 33.3% of A horizon soil samples referred to a very high degree of pollution. Obtained results will be useful for implementation of control measures of pollution and the remediation techniques. [ABSTRACT FROM AUTHOR]

Trace elements released by human activity are ubiquitously detected in surface soil. The trace element contamination statuses of 20 sampling stations at two busy informal industrial sites of Harare city, Zimbabwe, were evaluated using geochemical indices. Spectrophotometric determinations of concentrations of trace elements in surface soil indicated generally higher values than the reference site and the average upper earth's crust. High contamination factors were observed for trace elements across sampling stations at Gazaland and Siyaso informal industrial sites. Concentrations exhibited heterogeneous distribution of trace elements in surface soil varying with the nature of activity at a sampling station. The pollution load index and degree of contamination suggested highly contaminated surface soil with Cd, Cu and Pb particularly where the following activities were done: (1) welding, (2) automobile maintenance and (3) waste dumping. These results may be very important to reduce soil contamination. Paving surfaces may help to reduce dispersal of trace elements deposited on surface soil to other stations and minimise human exposure via inhalation and contact. [ABSTRACT FROM AUTHOR]

Abstract In order to acquire a better knowledge of iron forms, clay minerals and the content and distribution of trace elements in soils mostly used for agriculture in the semi-arid Brava Island (Cape Verde), iron speciation, mineralogy and chemical contents in the clay-size fraction (<2 μm) of incipient soils developed on sediments and phonolitic pyroclasts was performed by Mössbauer spectroscopy, X-ray diffraction and neutron activation analysis. In contrast with the whole samples in the clay-size fraction of all the studied soils only Fe(III) was detected. Iron and chromium are depleted suggesting their occurrence as ferromagnesian and oxide minerals present in coarser particles. Rare earth elements are concentrated in the clay-size fraction, and significant differences are found in their distribution which may be partially due to oxidation, since Ce anomalies were observed. Among the other chemical elements studied, high concentrations of arsenic, bromine, and particularly antimony were found in the clay-size fraction of soils where all the Fe oxides are nano-sized, confirming the predominant adsorption of these elements on the nano-particles surface. The existence of significant amounts of these elements as well as of vitreous phases in fine particles of these soils may contribute to their mobility and accumulation in groundwater and in plants, both by absorption and by dust deposition onto the plant leaves. Highlights • REE enrichment in the clay-size fraction of sediments and phonolitic pyroclast soils. • High concentrations of As, Br and especially Sb in clay-size fraction. • Predominant adsorption of As, Br and Sb on nano-sized iron oxide particles surfaces. • Only Fe(III) occurs in clay-size fraction of the topsoils. • All the Fe oxides occurring in the fine fractions are nano-sized. [ABSTRACT FROM AUTHOR]

Despite the advanced activity of urban soil research, comparison of available trace metal contents in the soil of settlements has not yet been well investigated. First aim of research was the comparison of human impacts on urban soils in two Hungarian cities with different structure and development. To detect the sources of contamination, Szombathely and Sopron cities were separated into urban, suburban and peri-urban areas. Altogether 192 topsoil samples were collected at 0–20 cm in order to measure the physicochemical properties of the soil. Instead of total element contents, plant-available trace metal concentrations – Cd, Co, Cu, Ni, Pb, Zn – were determined using ICP-OES method. Due to different geological conditions, urban soils of the investigated settlements had similar properties in the case of pH, CaCO 3 and texture. In the case of plant available trace metals, limit excesses were found in urban and peri-urban areas mostly, but high values were recorded in the suburb. The amount of Cd available , Co available and Ni available were negligible. Downtown area was the most contaminated in both cities, but extremes appeared in suburban areas. In Szombathely, Cu available values were <40 mg Cu/kg, but extremely high Cu available results were found in the peri-urban viticulture areas of Sopron (>90 mg Cu/kg). The samples taken alongside busy roads near the city centre were Pb available -contaminated due to traffic. The Pb available concentration decreased slightly towards the suburban areas of the cities. The Zn available level exceeded 40 mg Zn/kg in soils taken from the watercourses of Szombathely. The highest trace metal pollution levels were recorded in soils of public parks of Sopron. Urban soils of Szombathely were more homogenized than urban soils of Sopron. Based on statistical analyses and comparison of the relations of urban, suburban, and peri-urban areas of Sopron to Szombathely, Szombathely's urban soils show more homogeneity. [ABSTRACT FROM AUTHOR]

Peri-urban horticulture performs environmental and socio-economic functions and provides ecological services to nearby urban areas. Nevertheless, industrialization and water pollution have led to an increase in the exposure of peri-urban vegetables to contaminants such as trace elements (TEs) and organic microcontaminants (OMCs). In this study, the occurrence of chemical contaminants (i.e., 16 TEs, 33 OMCs) in soil and lettuce leaves from 4 farm fields in the peri-urban area of the city of Barcelona was assessed. A rural site, outside the peri-urban area of influence, was selected for comparison. The concentration of TEs and OMCs ranged from non-detectable to 803 mg/kg dw and from non-detectable to 397 μg/kg dw respectively in the peri-urban soil, and from 6 · 10 −5 to 4.91 mg/kg fw and from non-detectable to 193 μg/kg fw respectively in lettuce leaves. Although the concentration of Mo, Ni, Pb, and As in the soil of the peri-urban area exceeded the environmental quality guidelines, their occurrence in lettuce complied with human food standards (except for Pb). The many fungicides (carbendazim, dimetomorph, and methylparaben) and chemicals released by plastic pipelines ( tris (1- chloro -2-propyl)phosphate, bisphenol F, and 2-mercaptobenzothiazole) used in agriculture were prevalent in the soil and the edible parts of the lettuce. The occurrence of these chemical pollutants in the peri-urban area did not affect the chlorophyll, lipid, or carbohydrate content of the lettuce leaves. PCA (Principal Component Analysis) showed that soil pollution, fungicide application, and irrigation water quality are the most relevant factors determining the presence of contaminants in crops. [ABSTRACT FROM AUTHOR]

Abstract: Ombrotrophic bogs are widely used to reconstruct the history of atmospheric metal deposition. Minerotrophic fens are potential archives as well but not much attention has been paid to them. This study examined the accumulation of major and trace elements in a poor fen of Fenghuang Mountain, NE China. Peat cores were dated by 210Pb and 137Cs techniques and elemental analyses were conducted after a two-step sequential digestion with HCl. Results suggest no significant pollution for other trace metals but Pb in Fenghuang Mountain area. Atmospheric soil dust flux (ASD) was calculated from the Ti content in the peat, and its decreasing trend over the last 60 years agrees with the East Asian winter monsoon (EAWM) shift, which suggests that ASD could be a potential climatic proxy for the EAWM variability in the region. [ABSTRACT FROM AUTHOR]

Trace elements contamination in soils caused by improper electrical waste (e-waste) recycling activities has attracted a lot of attention, and soaring levels of trace elements in e-waste recycling sites and the adjacent farmlands were well-recognized. However, the knowledge of pollution degree, ecological risk of trace elements in a whole e-waste recycling region was still limited. In this study, soil samples collection was conducted in a typical e-waste recycling region (approximately 30 km 2 ), and the concentrations of eight trace elements (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) were analyzed. Moreover, pollution index, enrichment factor, potential ecological risk, hazard quotient, and hazard index were calculated and used to assess the risk of the ecosystem and human health. The results showed that the mean concentrations of Cd, Cu, and Hg were significantly higher than their standard values of China; the excess portion was 90.2% for Cu, 87.4% for Cd, and 47.6% for Hg, indicating the regional contamination of these metals. The values of enrichment factors further demonstrated that Cd, Cu, and Hg were the most significantly enriched metals in the study area, which might be associated with e-waste activities. On the other hand, the concentrations of Cr and Ni were comparable with their background values, suggesting that they were mainly affected by soil parent materials. Health risk assessment indicated that the carcinogenic risk for the local habitants was unacceptable. Results of this study suggest that soil remediation strategies in e-waste recycling region should not only focus on the sites where e-waste recycling facilities located (i.e. hot spots), but consideration should also be given to control regional risk in farmlands. [ABSTRACT FROM AUTHOR]

In the last few decades, metal oxide nanoparticles have shown impact in various areas, and such an impact causes an increased release in a different environment like soil, water, or air. A limited number of studies on soils showed that the biochemical parameters were affected by the metal oxide nanoparticles. However, the influence of metal oxide nanoparticles on soil elements has not been investigated. For this aim, zinc oxide nanoparticles were applied to two different soils; also, the effect of planting on soil elements was investigated via the cultivation of various plants roots (taproots, fibrous, bulb). Soils were treated with zinc oxide nanoparticles at 0, 1.0 and 20.0 mg during 4 weeks. Then, surface soil samples were collected and digested using an acid digestion procedure. Some biochemically important elements (Ca, Zn, Mg, Fe, Al, Cu, Co, Ni) were determined using a microwave plasma atomic emission spectrometer. The effect of time and dose-dependent zinc oxide nanoparticles on the element contents of different soils was investigated during planting, and the results were statistically evaluated. [ABSTRACT FROM AUTHOR]

The aim was to evaluate eight methods of boron (B) extraction in different soils from Córdoba and Sucre, Colombia. 37 samples were collected at a depth of 0-20 cm and carried to Soil and Water Laboratory of University of Córdoba for its chemical characterization. The available boron was extracted with the following methods: modified hot water, calcium chloride (CaCl2) 0.05, hydrochloric acid (HCl) 0.05, barium chloride (BaCl2) 0.006, manitol 0.05 + CaCl2 0.01, Ca(H2PO4)2H2O 0.008 in mol L−1, mehlich-1 and ammonium acetate (NH4OAc) (1.0 mol L−1, pH = 7.0). The major quantity of boron was extracted with mehlich-1, HCl 0.05 mol L−1 and hot water, extracting 0.36, 0.29 and 0.26 mg kg−1, respectively. The extracting solution that correlated with the hot water method was HCl 0.05 mol L−1 (r = 0.81); followed by Ca(H2PO4)2H2O 0.008 mol L−1 (r = 0.62) and mehlich-1 (r = 0.54). According to characteristic and heterogeneity of soils, we recommend HCl method to extract available boron. [ABSTRACT FROM AUTHOR]

This study examined the dissolved organic matter (DOM) components of cow dung using a combination of fluorescence (excitation-emission matrix, EEM) spectroscopy and parallel factor (PARAFAC) modelling along with eleven trace metals using ICP-MS and nutrients (NH4+ and NO3−) using an AA3 auto analyser. EEM-PARAFAC analysis demonstrated that cow dung predominantly contained only one fluorescent DOM component with two fluorescence peaks (Ex/Em = 275/311 nm and Ex/Em = 220/311 nm), which could be denoted as tyrosine by comparison with its standard. Occurrence of tyrosine can be further confirmed by the FTIR spectra. Trace metals analysis revealed that Na, K and Mg were significantly higher than Ca, Fe, Mn, Zn Sr, Cu, Ni and Co. The NH4+ concentrations were substantially higher than NO3−. These results thus indicate that the dissolved components of the cow dung could be useful for better understanding its future uses in various important purposes. [ABSTRACT FROM AUTHOR]

This study is aimed at determining the level of environmental degradation as well as the concentration of trace elements in soil and stream sediments in order to evaluate the environmental impact of the mining operation. Twenty-five (25) soils and ten (10) stream sediment samples were collected from the study area. The physicochemical parameters were determined using appropriate instrumentation with the aid of a digital pH meter (Milwaukee meter) to measure the pH and electrical conductivity, total dissolved solids, moisture content and loss on ignition of the soil and stream sediment samples. The pH of the soil sample ranged from (6.10 to 7.19); Electrical conductivity ranged from (21.3 to 279.4 µS/cm), moisture content varied from (0.60% to 7.20%), and the LOI ranged from (2.03% to 18.62%). The results of the analysis showed that the concentrations of the trace elements in the soils and stream sediment samples were slightly higher than the background values. Plots of the trace elements in stream sediment samples show moderate, consistent decrease downstream except at points where there was mine water discharge into the main river. The pollution levels of heavy metals were examined in stream sediment and soil samples using different assessable indices, such as the enrichment factor, which showed significant-moderate enrichment for Cr, Th, Nb, Zn, Pb, Y and Zr and the geo-accumulation index, which showed practically moderate contamination with Cr, Ni and Sr based on regional background reference values. Geo-accumulation index and contamination index for soils and stream sediment revealed uncontaminated to moderate contamination. Likewise, elements with moderate contamination were Cr, Ni and Sr. The Pearson correlation showed that there were significant positive associations among selected metals in soil and stream sediment samples. [ABSTRACT FROM AUTHOR]