Dust Fall Research Articles

Initial pedogenic processes, mineral and chemical transformations and mobility of trace elements in Technosols on dumps of the former copper mines in Miedziana Góra and Miedzianka, the Świętokrzyskie Mts., south-central Poland

Technosols develop, among others, on dumps of former copper mines which became overgrown in spontaneous plant succession. The aim of the study was to determine the effect of pedogenesis on soil properties, mineral and geochemical composition, as well as operationally defined forms of As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn in Technosols developed on former mine dumps of the Miedziana Góra and Miedzianka former mining areas in south-central Poland. The studied Technosols were weakly developed soils with a simple soil profile comprising (1) C horizons in the subsoil and (2) O and A (or AC) horizons in the topsoil. The pHH2O of soils was 5.5–8.1. High soil pHH2O values were due to occurrence of carbonates (up to 25 %). The highest content of total organic carbon (TOC) and total nitrogen (TN) was found in O horizons as well as in A and AC horizons including buried A horizon. Soil magnetic susceptibility (χ) was 6.0–171.3 × 10–8 m3 kg−1. In each profile, the highest χ values were typical of A horizons including the buried A horizon. The most common minerals present in all profiles were quartz, kaolinite and mica. There were also admixtures of carbonates (dolomite, calcite), feldspars (orthoclase and albite), jarosite, goethite and traces of Fe sulphides. SEM-EDS analyses showed that soil substrate was subject to transformations of sulphides into Fe oxides. Moreover, pedogenic Cu carbonates were found in pores and on coarse materials. Technosols were enriched in Ag, As, Cd, Co, Cu, Hg, Mo, Ni, Pb, Sb, Zn, U and Th. The most mobile trace elements in the studied Technosols were Cd, Cu and Zn. Topsoil horizons of the studied soils contained a considerable share of Pb, Cu, Zn and Ni bound with soil organic matter. Arsenic was mostly bound with Fe oxides. First indicators of pedogenesis in the studied Technosols are (1) accumulation of soil organic matter in the topsoil followed by the decrease of soil pH and leaching of carbonates, (2) mineral transformations in the soil substrate (alteration of sulphides into Fe oxides and jarosite; origin of pedogenic Cu carbonates due to crystallization from soil solutions), (3) increase of magnetic susceptibility in the topsoil which may be an effect of atmospheric dust fall out or pedogenic transformation of Fe oxides into the phases with higher magnetic susceptibility and (4) the effect of soil properties, mineral composition and soil organic matter on geochemical forms of potentially toxic trace elements. The novelty value of the study lies in the identification of pedogenic Cu carbonates and the potential effect of soil-forming processes on the increase of topsoil magnetic susceptibility.

Radioactivity of Technosols on thermal power station ash disposal sites: Assessment of potential radiological human‐health risk

AbstractSoil radioactivity is a poorly recognized form of land degradation; however, there are regions all around the world where it can be dangerous to the environment and human health. The aim of the study was to analyze the radioactivity of Technosols developed on thermal power station (TPS) ash disposal sites. Total concentration of uranium (U), thorium (Th), and cesium (Cs), as well as the radioactivity of select radionuclides in Technosols were determined to recognize the level of radioactivity and to assess the potential radiological health risk. Total U, Th and Cs concentrations in Technosols were in ranges 1.5 to 11.3, 4 to 22.9, and 0.2 to 21.3 mg·kg−1, respectively. The radioisotope activities in Technosols (in Bq·kg−1) were in the 1.6–25.5 (137Cs); 29.2–1265 (40K); 26.2–99.9 (228Th); 27.9–100 (228Ra); 20.5–134. (226Ra); 32.8–177 (210Pb); 23.9–144 (238U); 1.2–7.0 (235U) ranges. The activity concentrations were slightly higher than the activities of non‐contaminated soils. Technosols developed from bituminous coal ash had higher 40K, 228Th, and 228Ra activity concentrations than soils developed from lignite ash. Artificial 137Cs occurred in surface horizons of Technosols due to fall of atmospheric dust enriched in 137Cs. Annual effective dose (AED) in Technosols amounted 0.07–0.16 mSv·a−1 and was somewhat higher than the global and Polish average (0.06 and 0.07 mSv·a−1, respectively) for outdoor external terrestrial radiation. The radioactivity of the investigated Technosols is slightly above the average radioactivity of native soils. The radiological human‐health risk related to the analyzed soils is low.

Mineral magnetism and palaeoenvironment recorded in loess in southern England

ABSTRACTExtensive research has focused on the loess deposits in southern England, aiming to unravel their stratigraphic and palaeoenvironmental significance. However, no systematic mineral magnetic study on these deposits has yet been undertaken. Here we address this by investigating the magnetic mineral composition and alignment of loess at two sites in southern England, Lowland Point (LP) on the Lizard Peninsula of Cornwall, and Pegwell Bay (PB) in eastern Kent on the Isle of Thanet. A set of rock magnetic analyses was conducted to understand mineral magnetism within the studied sections. In addition, the primary depositional origin of the magnetic fabrics as well as their overprinting caused by various possible post‐depositional processes were examined through anisotropy of magnetic susceptibility (AMS). The magnetic mineral composition is similar at both sites, derived from both sedimentary (aeolian) and post‐depositional processes. The AMS results show magnetic foliation that varies between the two sites, aligning with the bedding plane, indicating deposition from gravitational dust fall at the PB site, and a stronger wind transport energy at the LP site. Although the magnetic lineation of bulk AMS is relatively weak, there is a noticeable tendency towards alignment in most samples, with flow directions from the SE indicated at both sections if a strong wind is assumed at LP, although with a possible SW direction if a weaker wind is assumed. These observations may imply the preservation of palaeowind directions during dust transport, with a substantial southerly component, which contradicts previous assertions of dominant northerly or northeasterly winds. Indeed, a possible dominant southeasterly wind direction between 25 and 18 ka would suggest a limited influence of katabatic, westerly or polar northeasterly winds during dust transport, and rather may imply the effect of low‐pressure systems passing through the English Channel during that period.

Entrapment of atmospheric particle bound heavy metals by ferns as evidenced by lead (Pb) isotope and MixSIAR: Implications for improving air quality

Plant metal uptake can occur through both soil-root and atmospheric transfer from leaves. The latter holds potential implications for development of biofiltration systems. To explore this potential, it is crucial to understand entrapment capacity and metal sources within plants. As ferns absorb materials from atmosphere, this study focuses on two abundant fern species growing in densely populated and highly polluted regions of Eastern India. Gravimetric quantification, elemental concentration and Pb isotopic analyses were performed by segregating the ferns into distinct components: foliage dusts (loose dust (LD) and wax-bound dust (WD)) and plant tissue (leaves and roots). To understand metal sources, the study analyzes soil, and atmospheric particulates (PM10 and dust fall (DF)). Results indicate that, while LDs have soil dust influence, wax entraps atmospheric particulates and translocates them inside the leaves. Furthermore, roots demonstrate dissimilar isotopic ratios from soil, while displaying close association with atmospheric particulates. Isotopic composition and subsequent mixing model reveal dominant contribution from DF in leaves (53–73%) and roots (33–86%). Apart from DF, leaf Pb is sourced from PM10 (21–38%) with minimal contribution from soil (6–10%). Conversely, in addition to dominance from DF, roots source Pb primarily from soil (12–62%) with a meagre 2–8% contribution from PM10.

The rise and fall of dust in the Universe

ABSTRACT We estimate how the mean density of dust in the Universe varies with redshift, using submillimetre continuum observations and a method designed to minimize the effect of dust temperature. We have used the Herschel Astrophysical Terahertz Large Area Survey (Herschel-ATLAS) to show that the median temperature of dust in galaxies is $\simeq 22\ \mathrm{ K}$ and does not vary significantly with redshift out to z = 1. With this as our estimate of the mass-weighted dust temperature, we have used an 850-μm survey of the field of the Cosmological Evolution Survey (COSMOS) to estimate the mean density of dust in 10 redshift bins over the range 0 < z < 5.5. We find that the mean density of dust increased by a factor of ≃10 from z = 5 to z = 2, declined slightly to z = 1, and then steeply to the present day. The relationship between the mean density of dust and redshift is similar to the relationship between the mean star formation rate and redshift, although the increase for the former is steeper from z = 5 to z = 2. We have also used the submillimetre measurements to estimate the mean density of gas over the same redshift range. The values we estimate for the dust-traced gas are much lower and with a different redshift dependence than those for estimates of the mean density of atomic gas but similar to those for estimates of the mean density of the CO-traced gas. We find that the depletion time for the dust-traced gas in the Universe as a whole declines with redshift in the same way as seen for individual galaxies.

Characteristics of Atmospheric Dust Fall Pollution and Its Chemical Composition and Mass Reconstruction in Mentougou District of Beijing

To study the characteristics of atmospheric dust fall pollution in Mentougou District of Beijing, the monthly average monitoring results of 57 atmospheric dust fall samples from two state-controlled ambient air stations in Mentougou District from 2018 to 2022 were collected, and the atmospheric dust fall pollution status and its time variation characteristics in Mentougou District were analyzed. In order to explore the characteristics of chemical components of atmospheric dust fall and the results of quality mass reconstruction and their sources, 57 dust fall samples were collected using the active suction method at the Sanjiadian State-controlled Ambient Air Station. The mass concentration of dust fall and its chemical components were measured, the characteristics of chemical components in atmospheric dust fall were studied, and the mass reconstruction of the main components of atmospheric dust fall was performed using particle mass reconstruction technology. The reliability of the mass reconstruction results and the reasons for its undetermined components were also discussed. The results showed that from 2018 to 2022, the monthly dust fall in Mentougou District of Beijing changed periodically, being the maximum in April or May in spring and the minimum in October or November in autumn, and the maximum monthly dust fall was 3.2 to 8.4 times the minimum monthly dust fall. The order of the quarterly average monthly dust fall was as follows:spring>summer>autumn>winter, and the dust fall mainly came from spring and summer, accounting for 40.1%-43.0% and 23.8%-37.5% of the total annual dust fall, respectively. The annual average monthly dust fall in Mentougou District of Beijing showed a significant downward trend. The dust fall in 2022 had decreased by 52.8% compared with that in 2018, with an average annual decline of 13.2%, which was related to the improvement in the fine management level of urban environmental protection in Beijing in recent years. In 2021, soil dust had a significant impact on dust fall in Mentougou District, with an actual contribution of 44.2%. The chemical components in the atmospheric dust fall in Mentougou District were mainly water-soluble ions, crustal elements, organic carbon(OC), and elemental carbon(EC). The total mass of the measured chemical components accounted for 65.0% of the mass fraction of the dust fall. The secondary organic carbon(SOC) was also an important component of the atmospheric dust fall, and its mass concentration was 13.5 μg·m-3, accounting for 96.4% of the mass fraction of OC. The main components of atmospheric dust fall mass reconstruction were crust element fugitive dust, organic matter(OM), SO42-, NO3-, NH4+, trace elements, EC, and Cl-, with mass concentrations of 34.8, 28.0, 20.6, 15.0, 5.6, 4.3, 3.2, and 2.2 μg·m-3, accounting for 25.5%, 20.6%, 15.1%, 11.1%, 4.1%, 3.2%, 2.3%, and 1.6% of the dust fall quality, respectively. The atmospheric dust fall mainly came from the soil dust, construction cement dust, biomass combustion, waste incineration, and secondary transformation process. The measured mass concentration of atmospheric dust fall had a good correlation with the reconstructed mass concentration of chemical components, and the determination coefficient R2 was 0.8173. The undetermined components in the mass reconstruction results accounted for 16.5% of the dust fall mass, of which the particle bound water(PBW) in the dust fall accounted for 6.2% of the dust fall mass, and the remaining undetermined components might have been related to the unmeasured components, the selected estimation coefficient of OM and crustal elemental dust, the particle size composition, the selected chemical component analysis method, and its measurement error.

Risk Assessment of Heavy Metals in Dust Fall Around Reservoirs in Typical Ecologically Fragile Areas and Traceability Based on APCS-MLR Model

To assess the health risk status and pollution sources of heavy metals in the atmosphere of ecologically vulnerable areas, the surrounding area of Dahekou Reservoir in Xilingol League was selected as the study area. From 2021 to 2022, 12 monitoring points for atmospheric dust fall were collected for a period of one year. A total of 144 samples were collected to determine the contents of eight types of heavy metals, namely Cr, Ni, Pb, Cu, Zn, Mn, As, and Cd. The potential ecological index (Eri) and health risk assessment model were used to assess the risk level of atmospheric heavy metals on ecological security and human health. The analysis of enrichment factors, principal components, and the model of absolute principal component multiple linear regression (APCS-MLR) receptor were used to analyze the sources of heavy metal pollution qualitatively in the atmosphere of the study area. The results showed that:① the mean value of the comprehensive potential ecological risk of heavy metals in the annual atmospheric dust fall in the study area was at a high ecological risk, and only the Cd value was at a very high risk level among the heavy metals, whereas the remaining were at a slight risk. ② The results of the health risk showed that intake by hand, mouth, and skin contact were the main exposure routes, which led to non-carcinogenic and carcinogenic risks. Children were under non-carcinogenic and acceptable carcinogenic risks in different months. During those months, the main source of the risks was As. ③ Through enrichment factor analysis, principal component analysis, and APCS-MLR receptor model calculation, the results revealed that the proportion of wind-blown sources was the largest, accounting for 37.82%, and the contribution rates of coal combustion and traffic sources to Cu, Cd, Pb, and Zn were 73.01%, 40.22%, 70.31%, and 32.82%, respectively. The contribution rate of mining activities to As was 42.59%, while that of industrial sources of Cd was 22.01%; the contributions of other human activity sources of Cd, As, Pb, and Zn were 21.12%, 34.40%, 23.04%, and 32.15%, respectively.

The Impacts of Molybdenum Exploration on Cd and Zn Contents in Surface Water: Evidence from a Molybdenum Mine in the Xiaoqinling Mountains

In order to study the impact of molybdenum ore development in a large molybdenum mining area in the Xiaoqinling Mountains on the water and sediment quality of the Wenyu stream, surface water, sediment, and surrounding rock samples were collected, and the Cd and Zn contents were analyzed. The pollution status and ecological risk degree of river water and sediment samples in the Wenyu stream watershed were evaluated using the single element pollution index method, geoaccumulation index method, Hakanson potential ecological risk assessment method, potentially toxic elements (PTEs) health risk assessment, and PTEs pollution comprehensive index method. Finally, the impact of mining development on the contents of Cd and Zn in the Wenyu stream were discussed, and the sources of pollution were identified. The study revealed that the levels of Cd and Zn in 23 water samples collected from the primary channel of the Wenyu stream were markedly higher compared to the unaffected contrast area. Similarly, the concentrations of Cd and Zn in the 17 sediment samples were significantly elevated compared to the average values in the reference area. These findings indicated that The Wenyu stream was heavily impacted by the molybdenum mining activities, resulting in a high ecological risk associated with the sediment in the primary channel. Acid mine drainage in the mining area, sediment release activities, and atmospheric dust fall are considered to be the main sources of PTEs polluting the Wenyu stream watershed. Relevant personnel should complete a thorough river water quality investigation and perform ecological environment restoration so as to ensure sustainable economic development.

Pollution Characteristics of Carbonaceous Components in PM10 and PM2.5 of Road Dust Fall and Soil Dust in Xi'an

To investigate the pollution characteristics of carbonaceous components in PM10 and PM2.5 of road dust fall and soil dust in Xi'an and enrich their source profiles, samples from five sites of road dust fall and 16 sites of soil dust were collected in Xi'an from April to May 2015. The ZDA-CY01 particulate matter resuspension sampler was used to obtain PM10 and PM2.5 samples, and the Model5L-NDIR OC and EC analyzer were used to determine the concentrations of organic carbon (OC) and elemental carbon (EC) in PM10 and PM2.5. The pollution and sources of carbonaceous aerosol in PM10 and PM2.5 were investigated by analyzing OC and EC characteristics, ratio, and the principal component analysis statistical model. The results showed that the proportions of OC in PM10 and PM2.5 at the various dust fall sites differed, ranging from 6.0% to 19.4% and 7.6% to 29.8%, respectively. The ratios of EC in PM10 and PM2.5at the different dust fall sites were relatively small, accounting for 0.6%-2.2% and 0.2%-3.6% in urban sites, respectively; however, EC was almost undetectable in most peripheral soil dust. The proportions of carbonaceous components in PM10 and PM2.5 followed the order of urban road dust fall>external control dust>river beach soil dust>soil dust and urban road dust fall>soil dust>external control dust>river beach soil dust, respectively. OC dominated the carbonaceous aerosols at the different sites, which was relatively low in urban road dust fall. The OC to total carbon (TC) ratios in PM10 and PM2.5 at urban road dust fall were 85.2%-95.3% and 87.9%-98.9%, respectively. The OC to TC ratios in PM10 and PM2.5 of soil dust were relatively high, exceeding 99%. Carbonaceous components were primarily concentrated in fine particles. The pollution distribution of carbonaceous components in the urban road dust fall sites was consistent, whereas that in the different soil dust sites were quite different. The carbonaceous components in urban road dust fall and soil dust were primarily affected by pollutant source emissions such as biomass burning, coal burning, gasoline, and diesel vehicle exhaust. There were differences in the source contribution rates of carbonaceous aerosols in PM10 and PM2.5.

Indoor Airborne Microbiome and Endotoxin: Meteorological Events and Occupant Characteristics Are Important Determinants.

Airborne bacteria and endotoxin may affect asthma and allergies. However, there is limited understanding of the environmental determinants that influence them. This study investigated the airborne microbiomes in the homes of 1038 participants from five cities in Northern Europe: Aarhus, Bergen, Reykjavik, Tartu, and Uppsala. Airborne dust particles were sampled with electrostatic dust fall collectors (EDCs) from the participants' bedrooms. The dust washed from the EDCs' clothes was used to extract DNA and endotoxin. The DNA extracts were used for quantitative polymerase chain (qPCR) measurement and 16S rRNA gene sequencing, while endotoxin was measured using the kinetic chromogenic limulus amoebocyte lysate (LAL) assay. The results showed that households in Tartu and Aarhus had a higher bacterial load and diversity than those in Bergen and Reykjavik, possibly due to elevated concentrations of outdoor bacterial taxa associated with low precipitation and high wind speeds. Bergen-Tartu had the highest difference (ANOSIM R = 0.203) in β diversity. Multivariate regression models showed that α diversity indices and bacterial and endotoxin loads were positively associated with the occupants' age, number of occupants, cleaning frequency, presence of dogs, and age of the house. Further studies are needed to understand how meteorological factors influence the indoor bacterial community in light of climate change.

A comparison of passive and active dust sampling methods for measuring airborne methicillin-resistant Staphylococcus aureus in pig farms.

Methicillin-resistant strains of Staphylococcus aureus (MRSA) are resistant to most β-lactam antibiotics. Pigs are an important reservoir of livestock-associated MRSA (LA-MRSA), which is genetically distinct from both hospital and community-acquired MRSA. Occupational exposure to pigs on farms can lead to LA-MRSA carriage by workers. There is a growing body of research on MRSA found in the farm environment, the airborne route of transmission, and its implication on human health. This study aims to directly compare two sampling methods used to measure airborne MRSA in the farm environment; passive dust sampling with electrostatic dust fall collectors (EDCs), and active inhalable dust sampling using stationary air pumps with Gesamtstaubprobenahme (GSP) sampling heads containing Teflon filters. Paired dust samples using EDCs and GSP samplers, totaling 87 samples, were taken from 7 Dutch pig farms, in multiple compartments housing pigs of varying ages. Total nucleic acids of both types of dust samples were extracted and targets indicating MRSA (femA, nuc, mecA) and total bacterial count (16S rRNA) were quantified using quantitative real-time PCRs. MRSA could be measured from all GSP samples and in 94% of the EDCs, additionally MRSA was present on every farm sampled. There was a strong positive relationship between the paired MRSA levels found in EDCs and those measured on filters (Normalized by 16S rRNA; Pearson's correlation coefficient r = 0.94, Not Normalized; Pearson's correlation coefficient r = 0.84). This study suggests that EDCs can be used as an affordable and easily standardized method for quantifying airborne MRSA levels in the pig farm setting.

Design and fabrication of dust removal nanoarray structure on the surface of solar cell glass cover

A nanoarray structure was constructed on the quartz glass cover surface, which had both strong dust removal ability and significant anti-reflection. Firstly, a structure model of dust removal nanoarray was established to investigate the effects of the structural parameters such as the period, the depth, and the duty ratio. Then a nanoarray structure was prepared on the glass surface with nano-imprinting and plasma etching, then modified with atomic layer deposition to adjust its structural parameters. The results show that the dust removal performance of the glass cover improved by about 14% after being constructed a 500-nm period nanoarray structure. As the etching time and the number of deposited layers increased, the dust removal performance first increased and then decreased. After 30 min etching and 50 layers of atomic deposition, the nanoarray improved the dust removal performance of the glass cover by about 45%. Moreover, this nanoarray structure also had an obvious anti-reflection function, improving the transmittance within 350–1100 nm of the glass cover by 0.63% before dust fall, by 1.23% after the dust fall at a 30° inclination angle, and by 1.51% at a 60° inclination angle.

Assessment of radioactivity in particulate matter and soil from selected mining towns of Erongo region, Namibia

The presence of radionuclides in particulate matter (PM) associated with mining operations in communities located at the edge of the mine sites have been either greatly ignored or poorly understood, leading to the underestimations of the radionuclides concentrations in PM and health impact. In this study, measurements of radioactivity in PM and soil were made in the two mining towns of Karibib and Arandis to assess the human health radiological impact on the people around the mining sites. Dust fall samples were collected for a period of six months i.e. May 2017 to October 2017 using open bucket sampler procedure according to the American Society for Testing and Materials Standard Method (ASTM D1739) while some soil samples were collected using a soil auger. The samples were measured for the presence radionuclides using a well calibrated gamma-ray spectrometer coupled with a high purity germanium detector.In particulate matter samples, the mean activity concentrations of 226Ra, 238U, 232Th, 210Pb, and 40K were found to be 81.24±1.00, 57.99±2.61, 72.10±1.67, 55.89±6.21, 682±19.81 Bq.kg−1, respectively. Similarly, in soil samples, the mean activity concentrations were found to be 66.41±1.77 Bq.kg−1 for 226Ra, 52.79±3.40 Bq.kg−1 for 238U, 71.30±2.40 Bq.kg−1 for 232Th, Bq.kg−1 for 71.50±5.99 210Pb and 797.36±18.26 Bq.kg−1 for 40K. The activity concentrations revealed higher levels of radionuclides associated with the 238U series, which were distributed unevenly across the sites. The results were comparable to global values of 11 to 64 Bq.kg−1 for 238U, 17 to 60 Bq.kg−1 for 232Th, and 140 to 850 Bq.kg−1 for 40K.The activity concentrations were used to compute the absorbed dose (D), annual effective dose equivalent (AEDE), radium equivalent activity concentrations (Ra eq), external and internal hazard indices (H ex and H in), Gamma Index (Iγ), Alpha Index (Iα) and excess lifetime cancer risk (ELCR). The mean radiological parameters in most samples were found to be within acceptable limits, with Raeq 370 Bq.kg−1, which corresponds to an upper safe limit of AEDE of 1 mSv.yr−1, the prescribed safe limit by the International Commission on Radiological Protection (ICRP), and thus the potential radiological health effects may not be significant.

Multi-year monitoring of atmospheric dust fall as a sink for lead in an agro-industrial and petrochemical city of Argentina. Geo-accumulation and ecological risk assessment.

A multi-year monitoring data set of potentially harmful elements (PHEs), which are present in the chemical composition of atmospheric settleable particulate matter (SPM) in the urban, industrial and port areas in Bahía Blanca, was studied in order to assess potential ecological risk. The selected PHEs were metal elements of local and regional environmental importance (Cd, Cr, Cu, Ni, Pb, and Zn). Seventeen sampling campaigns were carried out between April 2013 and September 2019. After the microwave-assisted acid digestion of samples, the total contents of the PHEs were determined by ICP-OES. The annual dry deposition rate, the indexes associated with the potential ecological risk (RI) and the degree of geo-accumulation (Igeo) of each PHE were calculated. The results indicated that: (a) there are 3 groups (I, II, III) of PHEs with differentiated concentration levels, ranked I (Pb > Zn > Cu) > II (Cr ≈ Ni) > III (Cd) (p < 0.01) in all the studied areas; (b) the median of the total deposition rate was 1mgcm-2. month-1 with a significant relative contribution of Pb; (c) a considerable increase in geo-accumulation of Pb indicated that SPM was functioning as a sink for Pb, and also reflected a significant progressive increase in the potential ecological risk in all sites (p < 0.01); and (d) there were chemometrically identified potential sources of Pb, Cu and Zn emissions that would be associated mainly to the resuspension of dust from geogenic, industrial and urban origin, and to a lesser extent, to other gaseous emissions of the industrial sector. This work highlights three major aspects of environmental assessment: (a) the value of continuous monitoring as an important tool to detect long-term trends; (b) the importance of the role of dust fall as a useful environmental indicator of lead geo-accumulation; and (c) the great utility of geo-accumulation and potential ecological risk indices as rapid quantitative assessment tools of environmental pollution.

Impact of Mining and Ore Processing on Soil, Drainage and Vegetation in the Zambian Copperbelt Mining Districts: A Review

The regional environmental–geochemical surveying of the long-term impacts of mining and ore processing on a large part of the Zambian Copperbelt mining district was carried out by the Czech Research Group with cooperation of the Geology Department, University of Zambia, and the Geological Survey of Zambia in the period 2002–2018. This included the characterization of various sources of contamination, the extent of contamination of soils and crops, and the degree of contamination of river water and sediments. Solid speciation studies of potentially harmful chemical elements (PHEs), plant and human bioaccessibility studies, and a range of mineralogical techniques were used to assess the pathways of PHE cycling in terrestrial and aqueous systems and their impacts on human health. Ores of the Zambian Copperbelt mining district are mined for Cu and Co, but a number of other trace elements (Pb, As, Cd, Hg, Pb, Zn) gradually accumulated in soils and stream sediments. It was concluded that the most important problems related to ore mining and processing are the contamination of soil and crops due to dust fall out from tailing facilities and emissions from smelters. Moreover, leakages of solutions from tailing dams, insufficient technological control of their stability and breakdowns on pipelines transporting slurry from treatment plants to tailing impoundments cause contamination of water courses and deposition of metal(loids) in stream sediments. However, the contamination of the Kafue River water is relatively limited due to its high neutralization capacity. In contrast, in some Kafue River tributaries, especially those close to big mining centers, the concentrations of dissolved Cu and Co are high (up to 14,752 μg/L and 1917 μg/L) and exceed Zambian effluent limits. We also recommend measures that could contribute to minimizing the impact of ore mining and processing on the environment and the health of the local population.

New insight into the geochemical mechanism and behavior of heavy metals in soil and dust fall of a typical copper smelter

The desorption mechanism of heavy metals (HMs) in soil around the mining region are complex and affected by multiple pollution sources, including sewage discharge and atmospheric deposition. Meanwhile, pollution sources would change soil physical and chemical properties (mineralogy and organic matter), thus affecting the bioavailability of HMs. This study aimed to investigate the pollution source of HMs (Cd, Co, Cu, Cr, Mn, Ni, Pb, and Zn) in soil near mining, and further evaluate influence mechanism of dust fall on HMs pollution in soil by desorption dynamics processes and pH-dependence leaching test. Result presented that dust fall is the primary pollution source to HMs accumulation in soil. Additionally, the result of mineralogical analysis in dust fall revealed that quartz, kaolinite, calcite, chalcopyrite, and magnetite are the major mineralogical phases by XRD and SEM-EDS. Meanwhile, the abundance of kaolinite and calcite in dust fall is higher than in soil, which is the primary reason of higher acid-base buffer capacity of dust fall. Correspondingly, the weakened or disappeared of hydroxyl after the adding acid extraction (0–0.4 mmol· g−1) demonstrated that hydroxyl is the main participants of HMs absorption in soil and dust fall. These combined findings suggested that atmospheric deposition not only increases the pollution loading of HMs in soil, but also changes the mineral phase composition of soil, which would increase the adsorption capacity and bioavailability of HMs in soil. This is very remarkable that heavy metals in soil influenced by dust fall pollution could be released preferentially when soil pH is changed. The present results of this study would provide efficient and scientific targeted strategies for pollution control of HMs in soil near mining areas.

Loess or lake sediments: Resolving the origin of massive beds in the Lower Jurassic of southern Africa

Throughout Earth's history, dust deposits have been considered sensitive markers of fluctuations in global atmospheric circulation patterns. However, the identification of ancient dust deposits remains problematic, as their massive (structureless) nature impedes an unequivocal classification. In southern Africa, the Lower Jurassic Clarens Formation is dominated by intriguing structureless sandy siltstones that have been interpreted as loess even though classical diagnostic outcrop‐scale loess features are not observed. In this study, we utilized grain characteristics such as size, shape, sorting and fabric to assess the origin of these ubiquitous massive beds, as compared to strata with a known origin in the unit. Based on these grain characteristics, the massive beds can be grouped into six different facies types (Facies 1–6). Facies 1 has very similar grain features to the large‐scale cross‐bedded strata and thus it is interpreted as migrating dune deposits, only apparently massive. The dominant grain size with a large proportion of very fine‐grained sand and the random grain fabric suggests that Facies 2 resulted from sandy dust fall (short‐term suspension), whereas Facies 3 is interpreted as aeolian dust, having features consistent with modern and ancient loess due to its dominant silt grain size and random grain fabric. Features in Facies 4 are undiagnostic and could reflect a range of aeolian processes, although a dominant silt grain size may suggest an overwhelming loess component. Facies 5 and 6 show primary aeolian signatures with the preferred grain orientation being evidence of reworking in an aqueous setting (e.g., lake, stream). These six facies types represent a spectrum of depositional processes that occurred in response to erg migration and climatic changes along this Early Jurassic erg margin. Their facies diversity is evidence for: (1) dry and windy conditions in SW Gondwana during the Sinemurian to Pliensbachian, and (2) reworking of the aeolian sediments in various fluvial and lacustrine settings during the development of one of the largest known sand seas in Earth's history.

Source apportionment and source-specific risk evaluation of potential toxic elements in oasis agricultural soils of Tarim River Basin

As rapidly developing area of intensive agriculture during the past half century, the oases in the source region of the Tarim River have encountered serious environmental challenges. Therefore, a comparative analysis of soil pollution characteristics and source-specific risks in different oases is an important measure to prevent and control soil pollution and provide guidance for extensive resource management in this area. In this study, the concentration of potential toxic elements (PTEs) was analyzed by collecting soil samples from the four oases in the source region of the Tarim River. The cumulative frequency curve method, pollution index method, positive matrix factorization (PMF) model, geographical detector method and health risk assessment model were used to analyze the pollution status and source-specific risk of potential toxic elements in different oases. The results showed that Cd was the most prominent PTE in the oasis agricultural soil in the source region of the Tarim River. Especially in Hotan Oasis, where 81.25% of the soil samples were moderately contaminated and 18.75% were highly contaminated with Cd. The PTEs in the Hotan Oasis corresponded to a moderate level of risk to the ecological environment, and the noncarcinogenic risk of soil PTEs in the four oases to local children exceeded the threshold (TH > 1), while the carcinogenic risk to local residents was acceptable (1E−06 < TCR < 1E−04). The research results suggested that the Hotan Oasis should be the key area for soil pollution control in the source region of the Tarim River, and agricultural activities and natural sources, industrial sources, and atmospheric dust fall are the priority sources that should be controlled in the Aksu Oasis, Kashgar Oasis and Yarkant River Oasis, respectively. The results of this study provide important decision-making support for the protection and management of regional agricultural soil and the environment.

Role of intracameral Caspofungin in the management of Aspergillus keratitis: A case report

Abstract A 48-year-old male patient with a history of fall of dust in his right eye while driving came for a second opinion. On examination, he had a dry-looking ulcer with feathery margins and a hypopyon, suggestive of fungal keratitis. Scraping showed septate fungal filaments. Aspergillus niger grew in culture, and the patient was asked to use frequent natamycin eye drops. However, the hypopyon continued to increase, so ketoconazole tablets were added. Intracameral injection of Amphotericin B was advised, but in view of a severe shortage of the drug in the region, injection of Caspofungin (CAS) was given intracamerally with patient consent. With a combination of oral, topical, and intracameral antifungal medication, the ulcer slowly resolved over a period of 1 month, leaving behind a nebulomacular corneal scar in a quiet eye. Intracameral CAS may provide a safe and effective alternative to voriconazole and amphotericin B in the setting of Aspergillus keratitis.

工矿区不同类型生物结皮对大气降尘重金属的富集规律及其影响因子

PDF HTML阅读 XML下载 导出引用 引用提醒 工矿区不同类型生物结皮对大气降尘重金属的富集规律及其影响因子 DOI: 10.5846/stxb202203220700 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 宁夏自然科学基金项目(2021AAC03007); 国家自然科学基金项目(41961001, 31760144) Enrichment law of atmospheric dustfall heavy metal pollution by different types of biocrusts in mining areas and its influencing factors Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:大气降尘是矿区土壤重金属的主要来源,而生物结皮对大气降尘重金属有显著的富集作用。为探究不同类型生物结皮对大气降尘重金属的富集规律及其影响因子,选取宁东典型火电厂周边生物结皮广布区作为试验样地,3类生物结皮作为研究对象,并以临近裸土作为对照,对比分析了生物结皮富集大气降尘过程中土壤理化性质、酶活性及重金属含量的变化,采用相关分析、冗余分析和方差分解方法探讨了不同类型生物结皮的结皮层(A层)和层下土壤(B层)重金属含量与其土壤物理、化学性质及酶活性之间的关系。结果表明:燃煤烟尘是矿区大气降尘重金属污染的主要来源,涉及重金属元素包括Cd、Cr、Hg、Pb、Zn、As。生物结皮对源自大气降尘的重金属元素均具有显著的富集作用,且在不同演替阶段生物结皮间的富集规律完全一致:藓结皮>混生结皮>藻结皮;重金属综合污染指数评价结果显示:生物结皮对重金属具有表层富集效应,表现为A层污染程度高于B层。不同类型生物结皮A、B层综合污染指数存在显著差异,排序为:藓结皮>混生结皮>藻结皮;和对照相比,三类生物结皮均能通过富集大气降尘增加其A、B层养分和细颗粒物含量并改善土壤质地。方差分解结果表明,土壤化学性质是影响重金属含量解释度最高的单类环境变量,而相关性和冗余分析结果表明:有机质含量、电导率、酶活性、容重等是影响不同类型生物结皮A、B层土壤重金属含量的主要环境因子。 Abstract:Atmospheric dust fall is the main source of soil heavy metals in mining area. Biocrusts have a significant enrichment effect on heavy metal. In order to explore enrichment laws of how biocrust at different succession stages capture and concentrate heavy metals from atmospheric dust fall and its influencing factors, biocrusts wide-spread area around typically thermal power station in Ningdong Energy Industrial Base were taken as experimental site, three types of biocrusts were selected as study objects, and bare soils nearby were set as control. Based on the comparison analysis of changes of soil physicochemical properties, enzyme activities and heavy metal contents during the process of the enrichment of atmospheric dust fall by biocrusts, the relationship between heavy metal contents and soil physicochemical properties, enzyme activities of biocrustal layer (A horizon) and subsoil (B horizon) were analyzed by using the methods of correlation analysis, redundancy analysis and variance partitioning analysis. The results indicated that, flue gas was the main source of atmospheric dust fall heavy metal pollution, the involved heavy metal elements including Cd, Cr, Hg, Pb, Zn, As. Biocrusts had significant enrichment effect on heavy metal elements derived from atmospheric dust fall, and demonstrated a totally consistent law among biocrusts of different types as followed Moss crust >Mixed crust >Algal crust. The comprehensive pollution index indicated that biocrusts had a certain surface enrichment effect on heavy metals, which demonstrated as A horizon had a higher pollution level than that of B horizon. Compared with control, the three types of biocrusts all could enrich atmospheric dust fall and increase the nutrient, fine particles and improve its soil textures of A and B horizons. Variation partitioning results indicated that soil chemical properties were the single environmental variables of the highest degree of explanation influencing the heavy metals content. Redundancy and correlation analysis showed that soil organic matter, electrical conductivity, enzymatic activity, bulk density were the main environmental factors that influenced the heavy metals content in A, B horizons of different biocrusts. 参考文献 相似文献 引证文献