Elements In Soils Research Articles

Wykorzystanie testów kontaktowych do oceny gleb rolniczych

A soil has been of great concern throughout the world due to increasing environmental awareness and interest in the quality and management of such soils. Košice, the city in eastern Slovakia, is exposed to typical urban contamination sources such, furthermore, being the largest steel producer in Central Europe, it is long-term environmentally loaded by the iron and steel works that represent the largest source of (metallic elements) contamination in Slovakia. Five sampling sites located in the surrounding of U.S.Steel Košice (Slovakia), were selected, where almost all the agricultural soils were polluted by the metallic elements (Fe3+, Al3+, Mn2+, Cu2+, As3+). Agricultural soils toxicity was assessed with the toxicity bioassay -Phytotoxkit. Tests of limit concentrations of the elements (Fe3+, Al3+, Mn2+, Cu2+ and As3+) and Tests of soil concentration series (100-50-25-12.5%) - screening tests mustard Sinapis alba and Lepidium sativum were performed. The testing of the concentration range was performed in order to determine the values of 14d/EC50 and the possibility of comparing the ecotoxicity of metallic elements in agricultural soils (ISO 11269-2 Soil quality). Four concentrations were prepared in test plates: 12.5 - 25 - 50 - 100% soil samples. Concentration of metals in the soil samples ranged from 24400 to 39000 mg/kg for iron; 54000 to 85000 mg/kg for aluminum; 381 to 1035 mg/kg for manganese; 27 to 59 mg/kg for copper; and 7 to 36 mg/kg for arsenic. Based on the median concentration, the metals in the soils were arranged in the following decreasing order: Al3+ > Fe3+ > Mn2+ > Cu2+ > As3+. In the agricultural soils (4USS-PW) showed high contamination values for the iron with a median 35300 mg/kg, aluminum with a median 82500 mg/kg, manganese with a median 1027 mg/kg. The median level of arsenic in the soil (4USS-PW) was 34 mg/kg, this indicate higher concentration as the limit concentration is 25 mg/kg (Law No. 220/2004-2). Agricultural soils 1-3USS and 5USS showed less than 50% inhibition of the seed germination and root growth in the S.alba and L. sativum tests compared to the control, excepting of soil from 4USS plant west (values of the EC50 to 65%). Thus, the results of phytotoxicity tests were consistent with the chemical data. The rapid increase in urbanization, industrialization, human population, and traffic flow has resulted in the environment surrounding farmland ecosystems being critically contaminated by metallic elements.

Sorption of ciprofloxacin and enrofloxacin on alkaline cropland soil in semiarid regions: Roles of pH, ionic strength, and ion type

Animals manure and chemical fertilizers are widely applied to agricultural soils to mitigate soil fertility decline resulting from intensive farming practices. However, the use of antibiotics such as ciprofloxacin (CIP) and enrofloxacin (ENR) in these manures introduces certain environmental risks. The sorption of CIP and ENR in soil is influenced by various factors. Soil cations (i.e., Na+, K+, Mg2+, and Ca2+) and artificially introduced ions (NH4+) can affect the sorption behavior of CIP and ENR in alkaline agricultural soils through mechanisms such as ion exchange and competitive sorption. To investigate the effects of ionic strength and ion type on the sorption of antibiotics in alkaline agricultural soil, batch equilibrium experiments were conducted in this study. The results showed that the affinity of alkaline farmland soil to CIP and ENR was poor, and Kd was only 159 L/kg and 89 L/kg, respectively. Increases in temperature and pH inhibited CIP and ENR sorption on soil. Mineral elements in the soil strongly inhibited CIP and ENR sorption. Conversely, NH4+ promoted the Kd values of CIP and ENR by 46% and 221%, respectively. Additionally, under different influencing factors, both the sorption affinity (Kd) and sorption amount of ENR were lower than those of CIP. These findings indicate that ENR has a greater migration potential and poses a greater environmental risk in agricultural soils. Alkaline soil and mineral elements increase the migration potential of CIP, ENR, but the introduction of NH4+ in agricultural production can weaken the migration potential of them.

Exploring the potential of biochar for the remediation of microbial communities and element cycling in microplastic-contaminated soil

The detrimental effects of microplastics (MPs) on soil microbial and elemental raise significant environmental concerns. The potential of remediation with biochar to mitigate these negative impacts remains an open question. The remediation effects of biochar derived from corn and cotton straw on MPs concerning soil microorganisms and element cycling were investigated. Specifically, biochar induced substantial remediations in microbial community structure following MP exposure, restoring and fortifying the symbiotic network while exerting dominance over microbial community changes. A combined treatment of biochar and MPs exhibited a noteworthy increase in the abundance of NH4+, NO3−, and available phosphorous by 0.46–2.1 times, reversing the declining trend of dissolved organic carbon, showing a remarkable increase by 0.36 times. This combined treatment also led to a reduction in the abundance of the nitrogen fixation gene nifH by 0.46 times, while significantly increasing the expression of nitrification genes (amoA and amoB) and denitrification genes (nirS and nirK) by 22.5 times and 1.7 times, respectively. Additionally, the carbon cycle cbbLG gene showed a 2.3-fold increase, and the phosphorus cycle gene phoD increased by 0.1-fold. The mixed treatment enriched element-cycling microorganisms by 4.8–9.6 times. In summary, the addition of biochar repaired the negative effects of MPs in terms of microbial community dynamics, element content, gene expression, and functional microbiota. These findings underscore the crucial role of biochar in alleviating the adverse effects of MPs on microbial communities and elemental cycling, providing valuable insights into sustainable environmental remediation strategies.

Quantitative source apportionment and health risk assessment of trace elements in surface soils around the Shazand chemical industrial district, northwestern of Iran

A comprehensive study aimed at measuring trace elements pollution in the Shazand chemical industrial district, located in northwestern Iran, was conducted. Employing principal component analysis (PCA) and positive matrix factorization (PMF), we identified sources of trace elements and assessed associated health risks for inhabitants. The results showed that the mean concentrations of Pb, Cd, Ni, Zn, and As of 190 topsoil samples exceeded the background values, except for Cu. The total noncancer risk values for adults and children were 0.72 and 7.95, respectively, and the total carcinogenic risks were 8.46 E – 05 and 2.69 E – 04, respectively. The noncarcinogenic risk for children was above the threshold level, but low for adults. The total potential carcinogenic health risks for children exceeded the threshold of 1 E – 04 indicating a high carcinogenic risk for them, whereas the risk for adults was considered acceptable. Furthermore, As was the primary hazardous metal to human health, followed by Cd and Ni. According to the results of the PMF model, four factors were extracted for trace elements, including natural source, transportation sources, industrial sources, and agricultural sources, which contributed about 27.9%, 17.51%, 29.15%, and 25.44% to pollution of the area, respectively. Anthropogenic sources contributed far more to the potential health risks posed to inhabitants of the study area. These findings can assist governmental agencies in implementing targeted control strategies to prevent the contamination of heavy metals.

Oral bioaccessibility of potentially toxic elements in various urban environmental media

An important aspect of geochemical studies is determining health hazard of potentially toxic elements (PTEs). Key information on PTEs behaviour in the human body in case of their ingestion is provided with the use of in vitro bioaccessibility tests. We analysed and compared oral bioaccessibility of a wide range of PTEs (As, Cd, Ce, Cr, Cu, Hg, La, Li, Ni, Pb, Sb, Sn, Zn), including some that are not often studied but might pose a human health hazard, in soil, attic dust, street dust, and household dust, using Unified BARGE Method (UBM). Additionally, feasibility of usage of scanning electron microscope techniques in analyses of solid residuals of UBM phases was tested. Results show that bioaccessible fractions (BAFs) of PTEs vary significantly between individual samples of the same medium, between different media and between the gastric and gastro-intestinal phases. In soil, attic dust and street dust, bioaccessibility of individual PTE is mostly higher in gastric than in gastro-intestinal phase. The opposite is true for PTEs in household dust. In all four media, with the exception of Pb in household dust, among the most bioaccessible PTEs in gastric phase are Cd, Cu, Pb, and Zn. During the transition from the stomach to small intestine, the mean BAFs of most elements in soil, attic dust, and street dust decreases. The most bioaccessible PTEs in gastro-intestinal phase are Cu, Cd, Ni, and As. Micromorphological and chemical characterisation at individual particle level before and after bioaccessibility test contribute significantly to the understanding of oral bioaccessibility.

Rapid and High-Performance Analysis of Total Nitrogen in Coco-Peat Substrate by Coupling Laser-Induced Breakdown Spectroscopy with Multi-Chemometrics

Nitrogen is an important nutrient element for crop growth. Rapid and accurate acquisition of nitrogen content in cultivation substrate is the key to precise fertilization. In this study, laser-induced breakdown spectroscopy (LIBS) was used to detect the total nitrogen (TN) of coco-peat substrate. A LIBS spectrum acquisition system was established to collect the spectral line signal of samples with wavelengths ranging from 200 nm to 860 nm. Synergy interval partial least squares (Si-PLS) algorithm and elimination of uninformative variables (UVE) algorithm were used to select the spectral data of TN characteristic lines in coco-peat substrate. Univariate calibration curve and partial least squares regression (PLSR) were used to build mathematical models for the relationship between the spectral data of univariate characteristic spectral lines, full variables and screened multi-variable characteristic spectral lines of samples and reference measurement values of TN. By comparing the detection performance of calibration curves and multivariate spectral prediction models, it was concluded that UVE was used to simplify the number of spectral input variables for the model and PLSR was applied to construct the simplest multivariate model for the measurement of TN in the substrate samples. The model provided the best measurement performance, with the calibration set determination coefficient () and calibration set root mean square error (RMSEC) values of 0.9944 and 0.0382%, respectively; the prediction set determination coefficient () and prediction set root mean square error (RMSEP) had values of 0.9902 and 0.0513%, respectively. These results indicated that the combination of UVE and PLSR could make full use of the variable information related to TN detection in the LIBS spectrum and realize the rapid and high-performance measurement of TN in coco-peat substrate. It would provide a reference for the rapid and quantitative assessment of nutrient elements in other substrate and soil.

Occupational and human health risks of exposure to potentially toxic elements (PTEs) in top soils from steel fabrication workshops

IntroductionEnvironmental pollution caused by potentially toxic elements (PTEs) from anthropogenic sources has become a global concern due to its deleterious effect on humans and ecosystem health. Therefore, this study evaluated the concentrations of PTEs, pollution level and human health risk in topsoil from ten (10) steel fabrication workshops in Abeokuta, Ogun State, Nigeria. Materials and methodsTen (10) composite soil samples were collected in November 2023, from 10 different steel fabrication workshops in proximity to residence in Abeokuta, Ogun State, Nigeria. One (1) gram of processed sample was digested using aqua regia and PTE concentration estimated using atomic absorption spectrophotometer (AAS). Pollution index assessment was determined using enrichment factor (EF) and geo-accumulation index (I-geo) while descriptive statistics and correlation were subjected to statistical package for social sciences (SPSS). ResultsThe result showed that Iron (Fe) (11,500 – 42,100 mg kg−1), Lead (Pb) (10.7 – 583 mg kg−1), Chromium (Cr) (16.3 - 49.7 mg kg−1), Zinc (Zn) (34.6 – 343 mg kg−1), Manganese (Mn) (109 – 840 mg kg−1), Nickel (Ni) (2.23 - 25.3 mg kg−1), Copper (Cu) (16.6 -107 mg kg−1) and Cadmium (Cd) (2.23 - 25.3 mg kg−1) were present. Mean concentration for Pb (179±202 mg kg−1) is higher than the Canada soil guideline value (CSGV) (140 mg kg−1) while other PTEs are within the recommended limit. Pollution indices revealed EF (Cd and Pb) and I-geo (Cd) as the primary pollutants in the soil while the strong significant correlation between Cr, Cu and Mn p < 0.05. Cr, Ni, Pb and that of Cu, Mn, Ni, Pb, Zn p < 0.01 suggest an emanation from both geogenic and anthropogenic sources. Human health risk assessment revealed Fe as the most dosed PTE and ingestion as the major pathways of exposure especially to children being the most susceptible. Hazard index (HI) and total cancer risk (TCR) values for PTEs were <1 and within the acceptable threshold (1 × 10−6 – 1 × 10−4) except for Pb (3.93E+01; 1.16E-03) in adults respectively. ConclusionThe study showed that the topsoil from the steel fabrication workshop is polluted with Pb and Cu toxicity and the adult (residents and workers) population exposed to the soil is potentially at a non-cancer and cancer risk.

Assessing the impact of climate and crop diversity on regional greenhouse gas emissions and water demand of cropland

To tackle the challenges of climate warming and freshwater scarcity, evaluating greenhouse gas (GHG) emissions and water demand in agricultural production can contribute positively to sustainable agricultural practices. This study aims to quantify the GHG emissions and water requirements of three major grains in diverse environmental regions in China, with a specific focus on exploring their spatial heterogeneity due to regional differences. The parameterized DNDC model was used to quantify crop GHG emissions, while the Penman-Monteith equation was utilized to assess crop water demand. The result showed that the total GHG emission of major grain in China was 372.43 Tg/yr (CO2), 11.68 Tg/yr (CH4), 475.56 Gg/yr (N2O) respectively; and the water demand was 473.60 Gm3, in 2015. The Middle-lower Yangtze Plain (MLYP) had the highest emission and water demand. High-temperature and high-precipitation regions had greater GHG emission intensity; the intensity of different GHG emissions was significantly influenced by the type of crops. Late rice had the highest emission intensity. The geospatial distribution of GHG emissions and water demand displayed opposite patterns, with meteorological conditions and crop types as the main reasons. Soil bulk density was the most significant soil element influencing regional emissions. These results will help to assess the spatial heterogeneity of agricultural “water and carbon”, and the quantitative results can be used as evaluation indicators to establish resource- and environment- friendly agricultural cropping patterns suitable for different cropping regions.

Inorganic mineral elements in sandy soil, and their effect on agricultural crops "The soil of the Libyan Kufra Oasis as a model"

Inorganic mineral elements in sandy soil, and their effect on agricultural crops "The soil of the Libyan Kufra Oasis as a model"

Pollutant accumulation characteristics of substrates and mechanism of microbial action in different ecological ditches

ABSTRACT Ecological ditches serve as one of the important measures for the concentrated infiltration of stormwater in the construction process of sponge cities. Prolonged concentrated infiltration of stormwater can lead to the accumulation of pollutants and pollution risks in the substrate of ecological ditches. In this study, two different substrate ecological ditches were constructed, namely, a combined substrate ecological ditch with zeolite + ceramsite (EA), and a biological substrate ecological ditch (EB). The accumulation characteristics of pollutants and microbial mechanisms in the ecological ditches were evaluated by simulating the cumulative rainfall test for three years. Results showed that there was serious total nitrogen (TN) contamination in both EA and EB substrates, with mean values of 718.6 and 802.7 mg/kg, respectively. The average contents of potentially toxic elements (Cu, Pb, and Zn) in EA and EB substrates were higher than the background values of soil elements in China, and Cu posed considerable ecological risks to the environment. Proteobacteria was the dominant phylum and accounted for 32.85–41.33% in two ditches; the total number of denitrifying functional bacterial genera in the EB increased by 1.53% than EA, which proved that the biological substrate was more favourable for the growth of denitrifying microorganisms. The accumulation characteristics of pollutants and microbial mechanisms in the ecological ditches with different substrates above provide a reference for extending the service life of ecological ditch facilities.

Potential toxic elements (PTEs) in rhizosphere soils and crops under a black shale high geological background: Pollution characteristics, distribution and risk assessment

The LouShao Basin in Hunan Province is covered with two sets of black rock series containing various potential toxic heavy metal elements. The rock series are rich in various potential toxic heavy metal elements, and the weathered black shale is the main formation of local farmland soil, making it a typical area with high geological background in China. The purpose of this study is to assess the regional ecological and health risks by studying the correlation between the content of heavy metal elements enriched in rhizosphere soil, non-rhizosphere soil, and crops, and the concentration of heavy metal elements in the main source, black shale rocks. The results show that the elements in the black shale far exceed the world average of rock, severely affecting soil element concentrations. Se element is the most severely polluted in rhizosphere soil, exceeding the background value by 7 times. The concentration of heavy metals between rock-non-rhizosphere soil-rhizosphere soil-crops decreases linearly. The distribution of pollution has strong spatial autocorrelation, and the high geological background is the main reason. Pollution index results show significant pollution of Se, Cr, Hg, and Cd in crops, with the pollution of heavy metal element Cr in corn being extremely serious with Igeo = 6.71. The ecological risk order is Se > Cd > Cr > As > Pb > Hg. Humans mainly contact elements through skin contact and food chain intake. The HI value of heavy metal element Cd is greater than 1, indicating a high carcinogenic risk. Human exposure to Cd through skin contact and food chain intake may lead to related diseases such as kidney stones, and pose greater harm to children.

Rare earth elements (REEs) in soils and plants of Bangka Island (Indonesia) focussing on (hyper)accumulation

Abstract Background and Aims Indonesia is one of the most biodiverse regions in the world, but only a few metal hyperaccumulator plants have been reported from this vast country. This study aimed to discover rare earth element (REE) hyperaccumulator plants on Bangka Island, an area known to have REE enriched soils associated with tin placer deposits. Methods Prior to this study, herbarium specimens at the Universitas Bangka Belitung Herbarium were screened using non-destructive X-ray Fluorescence (XRF) scanning to detect specimens with anomalous REE concentrations. Fieldwork was subsequently conducted to collect samples from plant species suspected to be (hyper)accumulators based on the earlier XRF survey. Scanning electron microscopy and micro-XRF were used to verify the possibility of surface contamination by soil particles in plant specimens, and inductively coupled plasma atomic emission spectroscopy (ICP-AES) was used to determine total elemental concentrations in the plant material. Results Blechnopsis orientalis was found to hyperaccumulate REEs up to 3000 µg g−1 as well as arsenic up to 2100 µg g−1. The non-destructive analysis found no dust or soil contamination on B. orientalis specimens, confirming it as a genuine REE and arsenic hyperaccumulator. Additionally, the known REE hyperaccumulator Dicranopteris linearis was confirmed to be a REE hyperaccumulator on Bangka Island. Conclusion Blechnopsis orientalis is a REE hyperaccumulator with high potential for phytoextraction as it is a faster growing and larger species than D. linearis. As B. orientalis and D. linearis are native to Bangka Island, both should be studied further for their application in rehabilitating and extracting REEs from the (abandoned) tin mine areas.

Ecological and Health Risk Assessment of Potentially Toxic Elements in Soils from Black Soil Region, Northeast China

Ecological and Health Risk Assessment of Potentially Toxic Elements in Soils from Black Soil Region, Northeast China

Performance of agricultural factors on yield of sweet corn (Zea mays L. Saccharata ) - A review

Sweet corn producers and industries require more reliable cultivars which could be accomplished by hybrid breeding. However, progressive phenological growth may be affected by different factors. In this paper, we analyze the key factors that determine the growth and yield of sweet corn. Environmental factors such as temperature and photoperiod were strong determinants of dates of flowering and harvest which are often crucial to yield in diverse climates and agricultural systems, besides the country's pedological conditions, especially soil fertility, affected phenological development. The effectiveness of fertilization in improving sweet corn growth performance was significantly influenced by the soil characteristics, the water supply, the genotype, and the agrotechnological factors. Therefore, genetic improvement of hybrids should be incorporated into the climate and soil elements to stabilize sweet corn yields in various agroecosystems. Decisions made in the sowing period are very significant, as up to 30% of the obtained yield may depend on making the proper choice. Deviation from the optimum date (either early or late sowing) may decrease yield. When deciding about the sowing date of maize, one needs to consider climate, soil quality, geographical location, temperature, weed infestation, sowing seed quality, and the ripening time of the hybrid to be produced.

Soil pollution and elemental sources along Barapukuria coal mine, Bangladesh: Implications for eco-environmental and health risk assessment

For the first time, different pollution indices and a receptor model have been used to quantify eco-environmental and health risk assessments as well as identify the sources of potentially toxic elements in soil along the Barapukuria Coal Mine (BCM). Individual indices include enrichment and contamination factors showing the soil samples are moderately to highly contaminated by arsenic, cobalt, chromium, copper, lead, and zinc and heavily contaminated by sulfur. According to the geo-accumulation index, there is significant pollution with arsenic (1.24 ± 0.38), lead (1.49 ± 0.58), cobalt (1.49 ± 0.58), and sulfur (1.63 ± 0.38). Modified hazard quotient and ecological risk factor values also suggest low to moderate environmental risk hazards from the same elements. The nemerow pollution index, pollution load index, nemerow risk index, ecological risk index, and toxic risk index of soil range from 1.65 to 3.03, 0.82–1.23, 11–26, 77–165, and 6.82–11.76 suggest low toxic risk and moderate pollution, among other synergistic indices. Health risk assessment indicates that iron poses lower cancer risk for children than adults, while both face unacceptable cancer risks from inhaling chromium, cobalt, or arsenic. Principal component and phylogenetic cluster analysis extracted by the multiple linear regression with the absolute principal component score (APCS-MLR) model refer to the fact that manganese, iron, titanium, and nickel have originated from geogenic sources, while coal mine effluents enrich elements like arsenic, chromium, zinc, lead, uranium, sulfur, thorium, and zinc and phosphorous sourced from agriculture. In addition, geogenic and anthropogenic sources, including mine and agriculture activities, could potentially pollute the soil and ecosystem. The findings are crucial for regional and national planners in devising strategies to mitigate potentially toxic element pollution in soil along coal mine areas.

The Passive Environmental Effect of the Fungicide Benomyl on Soil Promoting Bacteria and Concentration of Some Important Soil Elements

Loam examples were gathered through the 2020-2021 rising periods, and the following measurements were made: Viable bacterial count by reducing root colonization. The outcomes of reviewing the impact of the fungicide Benomyl on development and viable microflora count revealed that the highest microbial count was in Al-Madaein 80 ×103 CFU/mL was recorded ., and the lowest count was 60 ×103 CFU/mL for the Aushtar area, The microbial viable count values for the affected microorganisms with Benomyl were decrease to 27×103 and 65 × 103 CFU/mL respectively. Those consequences specify that Benomyl has a robust choosiness contrary to microflora, especially when compared to the benomyl effect as folded dose, the microflora l count decreases to 25 ×103 CFU /mL in the Aushtar area and increases to 60 ×103 CFU/mL in Al-Madaein area. Whereas the study estimated the level of eight elements in soil (Mn, Fe, Cu, Zn, NO3, P, K, and NH4) cultured with Cyperus rotundus L. Which mentioned the effect of benomyl on these levels after three days of treatment. Mn concentration ranged between 5.96 to 9.11 ppm, while after fungicide benomyl, it decreased to 5.63 -6.53 ppm similar results were observed for other elements. The highest affected element was Mn in the Aushtar area. Those consequences designate that Benomyl has a stout fussiness in contrast to soil nutrients. The greatness of benomyl impacts on loam ingredients and procedures were minor, qualified to impact on mycorrhizal root foundation (reduction through benomyl).

The Content of Heavy Metals and Trace Elements in Different Soils Used under the Conditions of Homestead Plots and Field Agricultural Lands of Ukraine

The Content of Heavy Metals and Trace Elements in Different Soils Used under the Conditions of Homestead Plots and Field Agricultural Lands of Ukraine

Earthworm cast microbiomes differ across soil types in northern forests

Earthworms influence soil properties and element cycling, notably through the formation of casts. These biogenic structures are hotspots of microbial activity and play a role in soil carbon and nutrient dynamics. Previous research revealed that earthworm casts harbour distinct microbiomes from mineral soils under controlled laboratory conditions. But field studies are scarce, especially in northern forests currently undergoing earthworm invasion. Identifying drivers of earthworm cast microbiomes in the field and their potential differences with mineral soils and forest floors is therefore crucial to advance our understanding of their impact on soil functioning and nutrient cycling. Using a combined PLFA and DNA (ITS and 16S) approach, we characterized the fungal and bacterial communities of field-collected earthworm casts from three soil types: Luvisols, Brunisols (WRB: Cambisols), and Podzols. We compared them with those of surrounding mineral soils and forest floors. We did not find evidence of community filtering effects following gut transit and mixing of mineral soil and forest floor, as α- diversity and species richness were not reduced in casts. Cast microbiomes were dominated by taxa also found in forest floors and mineral soils. Yet they presented key differences in that they were systematically enriched in saprotrophic fungi and Bacteroidota and depleted in ectomycorrhizal fungi. Further, they were more similar to forest floor than mineral soil microbiomes. We also found that, although cast microbiomes were dominated by taxa common to casts of all sites, they differed across soil types. This finding highlights the prevailing role of pedogenesis in explaining the microbiome composition of field-aged casts. Our results also underscore the importance of sampling both forest floors and mineral soils when investigating the effects of earthworms on carbon and microbial dynamics in forest ecosystems.

Spatial diffusion of potentially toxic elements in soils around non-ferrous metal mines

This study focuses on the diffusion patterns of principal ore-forming elements (Pb and Zn) and associated elements (Cd, Cu, Cr, and As) in lead-zinc ore. Sampling points in upwind and downwind directions of lead-zinc ore areas at various densities (1 N/km2 – 4 N/km2) were categorized. This study analyzed the statistical relationship between the content of PTEs in the soil around lead-zinc ore and the source strength and dominant wind direction, constructed one-dimensional and two-dimensional diffusion model, and simulated the EER scope caused by PTEs. The findings indicate that: (1) concerning source strength, the content of PTEs in soils of high-density ore aggregation areas is significantly higher than in low-density ore aggregation areas. However, the impact of source strength decreases with decreasing ore grade, with a difference in Pb content of 1.71 times among principal ore-forming elements and almost consistent Cd content among associated elements. (2) Regarding the transport pathways, for most PTEs, the inverse proportion coefficients downwind are higher than upwind, approximately 1.18–3.63 times, indicating greater migration distances of PTEs downwind due to atmospheric dispersion. (3) By establishing a two-dimensional risk diffusion model, the study simulates the maximum radius of risk diffusion (r = 5.7 km), the 50% probability radius (r = 3.1 km), and the minimum radius (r = 0.8 km) based on the maximum, median, and minimum values statistically obtained from the EER. This study provides a scientific basis for implementing preventive measures for PTEs accumulation in soil within different pollution ranges. Different risk prevention and control measures should be adopted for PTEs accumulation in soil within the three ranges after cutting off pollution sources. Subsequent research should further investigate the impact and contribution of atmospheric transmission and surface runoff on the diffusion of PTEs in areas with high risk near lead-zinc ore.

Superposition principle of impact on the working environment of actuating elements for site preparation machines

Problem. The analysis of the ripper working elements designs showed that their improvement perspective direction is using vibration and impact actuating elements. They work by the principle of dynamic energy accumulation with its subsequent use. However, there are currently no approaches to determining the tip rational parameters with the dynamic cutting edge. Goal. The main hypothesis formation and justification of the superposition principle impact on the working environment of actuating elements for ripper-pick. Methodology. Analytical methods of studying the soil destruction process by site preparation machines equipped tip with a dynamic cutting edge were used. Results. The presented model that describes the soil destruction process by the tip with the dynamic cutting edge has been developed. It combines the work of static force, determined by the traction parameters of the base machine, and the work of dynamic forces, determined by the physical and mechanical conditions of the soil destruction process. As a result, we obtained an equation for determining the force to overcome soil cutting resistance by the tip with the dynamic cutting edge. Originality. We propose to apply the superposition principle of effecting several factors on the working environment simultaneously in the soil destruction process by ripper-pick, such as static and dynamic load, due to the possibility of energy accumulation with subsequent use. This would create the high-speed power pulse on the cutting edge to ensure the preliminary formation of the compressed zone in the massif, with decreases in the power intensity of the static load for complete separation of the soil element. Practical value. The presented hypothesis will allow the technological basis development of such systems creation and application to develop fundamentally new technical solutions, to create effective, safe and durable working elements.