Search Results (136)

This study investigates the environmental stability of ferronickel slag (FNS) and primary lead slags (GCS and FCS) from historical metallurgical complexes in Greece, in rainwater and seawater media. Leaching experiments revealed that nickel is the most mobile element from FNS (43.5 μg·g⁻¹ in seawater after 90 days). Chromium release, on the other hand, is very limited, not exceeding 0.04 μg·g⁻¹. In lead slags, zinc and lead exhibit significant leaching (up to 650 and 230 μg·g⁻¹, respectively), while arsenic release reaches 22.6 μg·g⁻¹. GCS contains pores primarily in the range of 50–90 Å. The majority of pore volume in FCS is centered around 30 Å. The porosity appears to have a significant effect on the element’s leachability. Pb, Zn, As, Sb, and Cd are released in significantly higher amounts from the finely porous FCS compared to GCS. Thermodynamic modeling was used to identify the pollutant speciation in water media in relation to the oxygen concentration. The release of toxic elements such as Cr from FNS and As from lead slags is enhanced under oxic (open-air) conditions. Therefore, their land disposal poses a greater environmental threat compared to sea disposal, where anoxic conditions prevail. Full article

Evolutionary processes involving sustainability are here expressed in units of classical mechanics, where newly evolved traits are distance, segments of evolutionary trees are time, and species as entire character sets are mass. Data arranged on a morphological evolutionary tree (caulogram) allow precise calculations of evolutionary velocity, acceleration, momentum and force, with force interpretable as resistance to environmental change. Stem-taxon trees of species of the moss family Streptotrichaceae and Pottiaceae tribe Pleuroweisieae were developed as sets of minimally monophyletic genera, and annotated with numbers of newly evolved traits per species. Calculations provided evidence that precise and comparative measures of the results of sustainable evolutionary processes may be calculated, and, as directly derived from expressed traits, are also accurate and informative about processes leading to resilience across multiple extinction events. The two groups evidenced similar, gradual evolutionary rates, implying that similar evolutionary processes occur across 110 my for Streptotrichaceae and 66 my for Pleuroweisieae, although habitats differ. Extension of sets of new traits per species into the past imply origination of the oldest extinct recognizable progenitors near the Permian–Triassic extinction event, when a cut-off in all data imply a complete over-haul of the character set for both groups, i.e., a major change in evolutionary mass. Speciation occurs in bursts. Extinction is gradual, the negative of acceleration. The rates of origination of genera over time for both groups are nearly the same as those previously proposed for genera of extinct horses. Plateaus in graphs of species per genus imply ancient quadratic patterns of speciation. The combination of process-governed stability through stasis of morphological traits, and of resilience as the ability to survive multiple extinction events has apparently little changed, and both contribute to sustainability over geologic time. Full article

High levels of phosphorus cause eutrophication, leading to water blooms and making the water undesirable in aquatic environments. Surface water pollution by phosphorus (P) is caused by both point and diffuse sources. Despite the recent technological advancements in wastewater phosphorus removal, this element persists in aquatic ecosystems, particularly in sediments, often in non-bioavailable forms (in the case of precipitation by aluminum salts) or within biomass associated with high concentrations of heavy metals, rendering it unsuitable for reuse. In this paper, we review the measures and methods commonly used for reducing or removing bioavailable phosphorus, with a focus on the strategies and methods for direct in situ phosphorus removal or reuse, including the use of microbial biofilms and aquatic macrophytes, natural and constructed wetlands, and biotised (biologically enhanced) solid-phase sorbents or woodchip bioreactors. This paper also highlights the significance of bioavailable phosphorus from both the hydrochemical perspectives, examining phosphorus speciation, solubility, and the geochemical interactions influencing mobility in water and sediments, and the biological perspectives, which consider phosphorus uptake, bioaccumulation in aquatic organisms, and the role of microbial and plant communities in modulating phosphorus cycling. This overview presents sustainable phosphorus management approaches that are key to reducing eutrophication and supporting ecosystem health. Full article

Milk and dairy products play a key role in the human diet but may also be vehicles for toxic contaminants, particularly heavy metals and metalloids (HMs), such as lead (Pb), cadmium (Cd), mercury (Hg), and arsenic (As). This integrative review examines peer-reviewed studies published between 2015 and 2025 to examine sources, occurrence, and health risks associated with HM contamination in milk and dairy products. Key sources include industrial emissions, agricultural runoff, contaminated feed and water, and inadequate packaging. This review highlights regulatory inconsistencies, limited surveillance, and underuse of metal speciation analysis, which hinder accurate toxicity assessment. Advances in trace-level HM detection systems are discussed in terms of sensitivity, accessibility, and feasibility. Studies from diverse geographic regions frequently report high levels of Pb and Cd in samples originating from industrialized areas in low- and middle-income countries. Health risk indicators, such as target hazard quotients (THQs) and margins of exposure (MOEs), often exceed safety thresholds, particularly in children, indicating significant public health risks, especially with prolonged exposure. These findings underscore the urgent need for systematic contaminant monitoring, harmonized regulations, source-focused mitigation policies, and investment in rapid, cost-effective testing technologies to safeguard milk and dairy product safety worldwide. Full article

Against the challenge of extreme lead (Pb) contamination (>15,000 ppm) in industrial polluted soils, where conventional agents fail to disrupt stable Pb–soil complexes—this study extends our prior cadmium (Cd) remediation research to validate amino acid ionic liquids (AAILs) for highly recalcitrant metals. Fifteen AAILs were screened via batch washing, with [Met][NO₃] (methionine-based) demonstrating the highest Pb removal efficiency. Single-factor optimization revealed that under the conditions of 0.8 mol/L, 6:1 liquid–soil ratio, 60 min, 85.4% Pb was removed from severely contaminated soil by [Met][NO₃]. Kinetic analysis using four common models showed that the second-order kinetic equation provided the best fit, indicating that Pb removal was predominantly driven by chemical reactions such as complexation or ion exchange. After washing, the contents of various Pb species were significantly reduced, thereby mitigating environmental risks. Notably, no substantial changes in soil texture were observed. However, a marked increase in organic matter content was detected, accompanied by decreases in soil pH and mineral element concentrations. Analysis of soil mineral composition, functional groups, and chemical speciation revealed that [Met][NO₃] primarily facilitated Pb removal through ion-exchange and coordination reactions. This study establishes [Met][NO₃] as a green agent with dual efficacy: it achieves high-efficiency remediation of severely Pb-contaminated soil while ensuring environmental sustainability, thus highlighting its potential for practical application. Full article

Polyploidisation is a very common phenomenon in the plant kingdom and plays a key role in plant evolution and breeding. It promotes speciation and the extension of biodiversity. It is estimated that approximately 47% of flowering plant species are polyploids, derived from two or more diploid ancestral species. In natural populations, the predominant methods of whole-genome multiplication are somatic cell polyploidisation, meiotic cell polyploidisation, or endoreduplication. The formation and maintenance of polyploidy is accompanied by a series of epigenetic and gene expression changes, leading to alterations in the structural, physiological, and biochemical characteristics of polyploids relative to diploids. This article provides information on the mechanisms of formation of natural and synthetic polyploids. It presents a number of examples of the effects of polyploidisation on the composition and content of secondary metabolites of polyploids, providing evidence of the importance of the phenomenon in plant adaptation to the environment, improvement of wild species, and crops. It aims to gather and systematise knowledge on the effects of polyploidisation on plant physiological traits, including stomatal conductance (Gs), transpiration rate (Tr), light saturation point (LSP), as well as the most important photosynthetic parameters determining biomass accumulation. The text also presents the latest findings on the adaptation of polyploids to biotic and abiotic stresses and explains the basic mechanisms of epigenetic changes determining resistance to selected stress factors. Full article

Ceria is an important redox catalyst due to the facile Ce³⁺/Ce⁴⁺ switching at its surface. Therefore, in situ determination of the oxidation state of surface cerium cations is of significant interest. Infrared spectroscopy of probe molecules such as CO holds great potential for this purpose. However, the ability of CO to reduce Ce⁴⁺ cations is an important drawback as it alters the initial cerium speciation. Dinitrogen (N₂), due to its chemical inertness, presents an attractive alternative. We recently demonstrated that low-temperature ¹⁵N₂ adsorption on stoichiometric ceria leads to the formation of complexes with Ce⁴⁺ cations on the (110) and (100) planes (bands at 2257 and 2252 cm⁻¹, respectively), while the (111) plane is inert. Here, we report results on the low-temperature ¹⁵N₂ adsorption on reduced ceria nanoshapes (cubes, polyhedra, and rods). A main band at 2255 cm⁻¹, with a weak shoulder at 2254 cm⁻¹, was observed. We attributed these bands to ¹⁵N₂ adsorbed on Ce³⁺ sites located on edges and corners as well as on {100} facets. In conclusion, ¹⁵N₂ adsorbs on the most acidic surface Ce³⁺ sites and enables their distinction from Ce⁴⁺ cations. Full article

Cyanide species pose an environmental concern as they inhibit important biological processes in humans and aquatic systems. There is more focus on free-CN and weak acid dissociables cyanide as hazardous species compared to strong acid dissociables due to their higher reactivity and toxicity. However, the strong acid dissociables cyanide also poses health concerns as it liberates free-CN under ultraviolet irradiation or when present in acidic solutions. Detection of strongly acid dissociables cyanide typically requires its digestion in acidic solutions and measurement of the gaseous HCN produced. A simple infrared spectroscopic method is described here to speciate and quantify three strong acid dissociables cyanide: [Fe(CN)₆]³⁻, [Co(CN)₆]³⁻, and [Au(CN)₂]⁻. The strategy involves precipitating the strongly acid dissociables cyanide using cetyltrimethylethylammonium bromide, capturing the precipitate on a polyethylene membrane, and quantifying the individual strongly acid dissociables cyanide from the IR spectrum recorded in transmission mode through the membrane. Controlling the particle diameter to be in the range of 0.2–2 µm is important. Particles less than 0.2 µm pass through the membrane, whereas particles larger than about 2 µm lead to nonlinearity in quantification. The average %recoveries for [Fe(CN)₆]³⁻, [Co(CN)₆]³⁻, and [Au(CN)₂]⁻ were 100% (%RSD = 7), 91% (%RSD = 7), and 101% (%RSD = 8), respectively. The detection limit for [Fe(CN)₆]³⁻ and [Co(CN)₆]³⁻ were both 20 ppb CN⁻, whereas [Au(CN)₂]⁻ was 100 ppb CN⁻. The detection range was 20–750 ppb CN⁻ for [Fe(CN)₆]³⁻ and [Co(CN)₆]³⁻ and 100–750 ppb CN⁻ for [Au(CN)₂]⁻ with a linear regression of R² = 0.999–1.000. Full article

Active and abandoned mining sites are significant sources of heavy metals and metalloid pollution, leading to serious environmental issues. This study assessed the environmental risks posed by potentially toxic elements (PTEs), specifically arsenic (As) and antimony (Sb), in the Technosols (mining residues) of the former Pejão coal mine complex in Northern Portugal, a site impacted by forest wildfires in October 2017 that triggered underground combustion within the waste heaps. Our methodology involved determining the “pseudo-total” concentrations of As and Sb in the collected heap samples using microwave digestion with aqua regia (ISO 12914), followed by analysis using hydride generation-atomic absorption spectroscopy (HG-AAS). The concentrations of As an Sb ranging from 31.0 to 68.6 mg kg⁻¹ and 4.8 to 8.3 mg kg⁻¹, respectively, were found to be above the European background values reported in project FOREGS (11.6 mg kg⁻¹ for As and 1.04 mg kg⁻¹ for Sb) and Portuguese Environment Agency (APA) reference values for agricultural soils (11 mg kg⁻¹ for As and 7.5 mg kg⁻¹ for Sb), indicating significant enrichment of these PTEs. Based on average I_geo values, As contamination overall was classified as “unpolluted to moderately polluted” while Sb contamination was classified as “moderately polluted” in the waste pile samples and “unpolluted to moderately polluted” in the downhill soil samples. However, total PTE content alone is insufficient for a comprehensive environmental risk assessment. Therefore, further studies on As and Sb fractionation and speciation were conducted using the Shiowatana sequential extraction procedure (SEP). The results showed that As and Sb levels in the more mobile fractions were not significant. This suggests that the enrichment in the burned (BCW) and unburned (UCW) coal waste areas of the mine is likely due to the stockpiling of lithic fragments, primarily coals hosting arsenian pyrites and stibnite which largely traps these elements within its crystalline structure. The observed enrichment in downhill soils (DS) is attributed to mechanical weathering, rock fragment erosion, and transport processes. Given the strong association of these elements with solid phases, the risk of leaching into surface waters and aquifers is considered low. This work underscores the importance of a holistic approach to environmental risk assessment at former mining sites, contributing to the development of sustainable remediation strategies for long-term environmental protection. Full article

Potentially toxic elements (PTE), such as cadmium (Cd), lead (Pb), and arsenic (As), threaten rice (Oryza sativa L.) crop productivity and pose significant risks to human health when they are present in soil. This review summarizes the current understanding of soil and rice contamination with As, Cd, and Pb to provide an in-depth understanding of the dynamics of these contaminants and the mechanisms regulating their flow from soil to plants. It focuses on the following aspects: (1) these metals’ geochemical distribution and speciation in soil–rice systems; (2) factors influencing the transformation, bioavailability, and uptake of these metals in paddy soils; (3) metal uptake, transport, translocation, and accumulation mechanisms in rice grains; and (4) the roles of transporters involved in metal uptake, transport, and accumulation in rice plants. Moreover, this review contributes to a clearer understanding of the environmental risks associated with these toxic metals in soil–rice ecosystems. Furthermore, it highlights the challenges in simultaneously managing the risks of As, Cd, and Pb contamination in rice. The study findings may help inspire innovative methods, biotechnological applications, and sustainable management strategies to mitigate the accumulation of As, Cd, and Pb in rice grains while effectively addressing multi-metal contamination in paddy soils. Full article

An experimental and computational methodology was developed for ionic speciation of Pb²⁺ and Cd²⁺ with dissolved organic matter (DOM) in surface seawater (SSW) from the Bay of Bengal (BoB) in eastern Bangladesh. Differential pulse anodic stripping voltammetry (DPASV) with a thin mercury film glassy carbon electrode (TMFGC) was used to measure free and DOM-bound Pb²⁺ and Cd²⁺. A continuous binding model was used to calculate the binding constants for metal ions with experimentally found complex ligands like DOM in the BoB. The ionic speciation and distribution of all major naturally occurring ions and toxic Pb²⁺, Cd²⁺, and DOM were calculated using a computational chemical equilibrium model, MINTEQA. We found that the change in pH with increasing dissolved carbon dioxide due to global warming will cause drastic changes in the bioavailability of Pb²⁺ by the year 2050. Full article

Wood ash, a byproduct of woody biomass power generation, has potential as an alternative K fertilizer due to its high K content and pH-raising properties. However, concerns remain about heavy metal contaminants like Cr and the limited understanding of element dynamics in soil–solution–crop systems after wood ash’s application. This study examined the effects of 1% (w/w) wood ash on element dynamics and komatsuna (Brassica rapa var. perviridis) uptake in low-K soil through a pot experiment. XRD was used to analyze mineral composition, SEM-EDS to observe surface and elemental properties, and XANES to examine Cr speciation in wood ash. Soil solution analysis covered macro- and micronutrients, heavy metals, anions, pH, and DOC, while crop element concentrations and aboveground dry weight were also quantified. The chemical speciation of Cu and Cr in a soil solution was modeled using Visual MINTEQ. Wood ash significantly increased K concentrations (from 17 mg/L to 650 mg/L) in the soil solution, along with Ca, Mg, P, and Mo, while reducing Ni, Mn, Zn, and Cd levels. Komatsuna K uptake surged from 123 mg/kg to 559 mg/kg, leading to a 3.31-fold biomass increase. Notably, the Cd concentration in the crops dropped significantly from 0.709 to 0.057 mg/kg, well below the Codex standard of 0.2 mg/kg. Although Cu and Cr concentrations rose in the soil solution, crop uptake remained low due to >99% complexation with fulvic acid, as confirmed by Visual MINTEQ modeling. This study confirms that wood ash is an effective K fertilizer, but emphasizes the need for risk mitigation strategies to ensure safe and sustainable agricultural application. Full article

Heavy metals, especially lead (Pb), is the major cause of pollution in the military shooting range soils. Bullets, which are primarily made of Pb, are a substantial source of this pollution. On speciation, this Pb is distributed into its different metal forms. Different physicochemical properties of the soil like pH, moisture content, cation exchange capacity (CEC), and organic matter play a very crucial role in the distribution, transformation, and bioavailability of the Pb. The concentration of Pb found in different shooting ranges is examined. Moreover, bullet weathering and the availability of contaminants in the soil are influenced by the physicochemical properties of the soil. For the management of firing range pollution, a variety of strategies have been investigated, including soil washing, phytoremediation, and chemical stabilization. This review focus on the pollution status of different shooting ranges, the impact of the physicochemical properties of soil on the distribution, speciation, and transformation of Pb, and different mitigation strategies to control Pb pollution in military shooting ranges. Full article

This study aims to investigate the influence of cadmium (Cd) speciation transformation on P-wave velocity under different soil moisture conditions, providing critical insights into the subsurface characteristics of contaminated soils. Taking Cd-contaminated soil as the research subject, P-wave velocity and the speciation distribution of Cd in soils with different moisture contents and Cd adsorption levels were measured. The results reveal that when the soil is contaminated by Cd, the porosity is altered and it eventually lead to change P-wave velocity. By increasing the moisture content of soils, the redox potential (Eh) rises and the pH decreases, which lead to the speciation transformation of Cd from carbonate-bound state (CAB), Fe-Mn oxide-bound state (FMO), and organic and sulfide-bound state (ORB) to the exchangeable state (EX). These transformations of Cd to EX result in the increase in soil porosity, which lead to the decrease in P-wave velocity. In addition, linear regression analysis was conducted the P-wave velocity (∆V) and the EX (∆EX) at various Cd adsorption levels. The analysis shows that there is a strong linear relationship between exchangeable Cd content and P-wave velocity, and the determination coefficient is about 0.9, which provides a reliable basis for monitoring soil Cd contamination by using P-wave velocity. This study provides valuable insights into the relationship between the speciation distribution of heavy metals in soil and the properties of acoustic wave. Full article

This study assessed PM_2.5 concentrations and heavy metal composition in blacksmith workshops located in Mekarmaju village, Bandung Regency, Indonesia. The PM_2.5 levels measured across seven workshops showed significantly elevated concentrations, ranging from 166.88 µg/m³ to 513.80 µg/m³, greatly exceeding the indoor air quality recommended by the World Health Organization (WHO). Chemical analysis revealed toxic heavy metals within PM_2.5, including iron (Fe), chromium (Cr), nickel (Ni), manganese (Mn), zinc (Zn), and lead (Pb), with total heavy metal concentrations varying significantly between workshops. The highest concentration was recorded in workshop B (61.8 µg/m³), while the lowest was in workshop F (6.1 µg/m³). These metals are associated with severe health risks such as respiratory and cardiovascular diseases, neurotoxicity, and increased cancer risk with prolonged exposure. Strong correlations between PM_2.5 and metals such as Fe, Cr, and Mn indicate that emissions from metalworking processes are primary sources of indoor pollution. Although this pilot study provides crucial baseline data, limitations such as a short sampling duration and a small sample size suggest the need for further research. Future studies should include long-term, continuous monitoring and detailed chemical speciation to enhance our understanding of occupational health risks. Full article