Search Results (4,473)

The accumulation of heavy metals in fish tissues is widely recognized as an indicator of aquatic environmental pollution, and the analysis of their content provides a basis for assessing ecological risk and the safety of aquatic food. The European eel (Anguilla anguilla) is a species frequently used as a bioindicator in environmental studies due to its wide geographic distribution, long life cycle, and high capacity for bioaccumulation of heavy metals in various tissues. The aim of this study was to assess the variation in the accumulation of heavy metals, i.e., mercury (Hg), lead (Pb), arsenic (As), and cadmium (Cd), in the tissues (muscle, liver, gonads, and gills) of European eels caught in two locations in Polish inland waters. The obtained results showed significant differences both in the concentration levels of individual elements and in their co-occurrence in the examined tissues. The statistical methods used, including correlation analysis, heat maps, and principal component analysis (PCA), allowed for a comprehensive assessment of the relationships between metals and the identification of factors differentiating the studied populations. The obtained results clearly indicate that fish residing in similar environments for long periods exhibit significant differences in heavy metal content in various fish tissues. Fish obtained from environments with potentially higher levels of heavy metal inputs, such as the Oder River EMU compared with the Vistula River EMU, showed higher levels of heavy metal accumulation in tissues. This study also found that the concentration of heavy metals tested did not exceed the safe standards for human fish consumption. Full article

Cadmium (Cd) pollution poses significant threats to ecosystems and human health, with agricultural soils in China particularly affected. Ilex verticillata, a popular ornamental plant, has not been extensively studied for its response to Cd stress. This study investigated the physiological and molecular mechanisms underlying Cd stress tolerance in I. verticillata, focusing on auxin signaling pathways. Under Cd stress (500 mmol/kg soil), I. verticillata exhibited inhibited stem growth, reduced photosynthetic capacity, and elevated oxidative stress markers such as malondialdehyde, H₂O₂, ·O₂⁻, and antioxidant enzyme activities. Transcriptomic analysis revealed 3750 differentially expressed genes (DEGs) with significant enrichment in auxin signaling pathways. Six nucleus-localized IvIAA genes were identified and shown to interact with the transcription factor IvMYB77, suggesting a regulatory module in Cd stress responses. These findings highlight the role of auxin signaling in mediating Cd stress tolerance and provide insights into the molecular adaptation of I. verticillata to heavy metal pollution. Full article

For future Mars colonization, crop production will be a challenge due to the chemical composition of the Martian Regolith, which contains perchlorates and heavy metals. This research was conducted to determine if the use of Arbuscular Mycorrhizal Fungi (AMF), Plant Growth-Promoting Bacteria (PGPB), and fertilization have a positive effect on tomato growth in a Martian Regolith Analog. The analog contains 52.54% SiO₂, 1.81% TiO₂, 17.66% Al₂O₃, 9.46% Fe₂O₃, 0.145% MnO, 3.43% MgO, 7.09% CaO, 3.95% Na₂O, 1.96% K₂O, and 0.55% P₂O₅. Two hundred and forty tomato plants were grown for 45 days. One hundred and twenty tomato plants grown over perchlorate-polluted analog (1% m/m) died in less than 2 weeks, while 120 tomato plants grown in a non-polluted analog survived. Forty-eight plants supplemented with Long–Ashton solution increased their shoot length 100% more than the control plants and the plants inoculated with the commercial AMF formulation TM-73^MR and PBB; the latter showed 25% mycorrhizal colonization. There was no significant difference between the growth parameters of inoculated plants and non-inoculated plants. However, there was a significant difference compared to the plants supplemented with Long–Ashton solution. The perchlorate is toxic to tomato plants, and the metal content of the analog was not a limiting factor for tomato growth or AMF colonization. Full article

To investigate the seasonal characteristics, sources, and regional transport patterns of precipitation components in the high-elevation mountainous regions, field sampling was conducted at Mt. Heng (Hunan, South China) from June 2021 to May 2022. In total, 114 precipitation samples were collected and subjected to chemical analysis, including pH, major inorganic ions, and heavy metals. During the study period, the precipitation at Mt. Heng was generally weakly acidic. The concentrations of metals and acidic anions (NO₃⁻ and SO₄²⁻) were higher in the winter and lower in the summer, whereas the concentration of the primary neutralizing cation, NH₄⁺, peaked during the summer. An association was observed between precipitation pH and metal concentrations, whereby acidic precipitation samples exhibited marginally elevated metal concentrations overall. An additional analysis of winter precipitation chemistry at Mt. Heng revealed an increasing trend of ions from 2015 to 2018, followed by a decrease from 2019 to 2021. This trend coincided with the concentrations of NO₂ and SO₂ in the surrounding cities, reflecting the results of clean air actions. The results of the source analysis revealed five major sources: secondary sources (41.5%), coal combustion (24.7%), a mixed source of biomass burning and aged sea salt (11.6%), dust (10.8%), and industrial emissions (11.4%). Backward trajectory cluster analysis revealed that air masses originating from the northern regions were generally more polluted than those from the southern regions. This study provides fundamental data and scientific support for regional atmospheric pollution control and ecological protection in South China. Full article

Plastic pollution is a major global challenge, especially nanoplastics (NPs) emerging as harmful pollutants due to their small size, reactivity, and persistence in ecosystems. Among them, cigarette butts composed of cellulose acetate (CA) are one of the most widespread and hazardous sources of terrestrial NPs. In this study, the immunotoxic, biochemical, and histopathological effects of cellulose acetate nanoplastics (CA-NPs) derived from smoked cigarette butts (SCB-NPs), unsmoked cigarette butts (USCB-NPs), and commercial cellulose acetate (CCA-NPs) were evaluated on the earthworm Allolobophora caliginosa. Adult worms were exposed for 30 days to 100 mg/kg CA-NPs in artificial soil under controlled laboratory conditions. Results revealed that SCB-NPs induced the most pronounced alterations, including increased lysozyme and metallothionein levels, reduced phagocytic and peroxidase activities, and depletion of protein and carbohydrate reserves. Histological examination showed vacuoles in epithelial layer vacuolization, space between muscle fiber disruption, and degeneration in gut and body wall, especially under SCB-NP exposure. USCB-NPs and CCA-NPs caused milder but still significant effects. Taken together, these findings highlight that the high toxicity of SCB-NPs is due to the presence of combustion-derived toxicants (nicotine, polycyclic aromatic hydrocarbons, and heavy metals), which exacerbate oxidative stress, immune suppression, and tissue damage in soil invertebrates. This study underscores the ecological risk of cigarette butt-derived NPs and calls for urgent policy measures to mitigate their terrestrial impacts. Full article

Heavy metal pollution poses a serious threat to soil ecosystems worldwide, as long-term exposure can alter microbial community functioning and reduce overall ecosystem resilience. This study investigated the impact of heavy metal contamination in technogenic industrial areas of the East Kazakhstan Region on soil microbial communities. Soil samples were collected for chemical and metagenomic analyses. Concentrations of Zn, Pb, Cu, and Cd were quantified by flame atomic absorption spectrometry (FAAS). Using long-read whole-metagenome nanopore sequencing, we conducted strain-level profiling of soils with different levels of metal contamination. This approach provided high-resolution taxonomic data, enabling detailed characterization of microbial community structure. Heavy metal exposure did not significantly reduce microbial diversity or richness but influences the quality of community composition. Metal-resistant taxa dominated contaminated soils. Overall, the results highlight the value of long-read sequencing for resolving strain-level responses to environmental contamination. Full article

Floods and wildfires are two extreme environmental events with significant yet different impacts on soil health and on two particularly important soil pollutants, heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs), which are directly associated with ishytoxic properties and their ability to enter the food chain. The present study includes a methodological approach that was based on a literature review of published studies conducted worldwide regarding these two phenomena. The main forms of both pollutants, their possible sources and inevitable deposition onto the soil surface, along with their behavior–transport–mobility, and their residence time in soil were investigated. Furthermore, the changes that both HMs and PAHs induce in the physicochemical properties of post-flood and post-fire soils (in soil pH, Cation Exchange Capacity (CEC), organic matter content, porosity, mineralogical alterations, etc.), are investigated after a literature review of various case studies. Wildfires, in contrast to floods, can more easily remove large quantities of heavy metals into the soil ecosystem, most likely due to the intense erosion they cause. At the same time, floods appear to significantly burden soils with PAHs. In wildfires, the largest mean increases were observed for Mn (386%), Zn (300%), and Cu (202%). In floods, Pb showed the highest mean increase (534%), with Cd also rising substantially (236%). Regarding total PAHs, mean post-event concentrations reached 482.3 μg/kg after wildfires, compared to 4384 μg/kg after floods. Changes in the structure and chemical composition of flooded and burned soils may also affect the mobility and bioavailability of the pollutants under study. Overall, these two phenomena significantly alter soil quality, affecting both ecological processes and potential health impacts. Full article

Hetero-multicomponent metal oxide catalysts are attracting increasing attention for wastewater remediation due to their tunable band structures, synergistic redox activity, and enhanced stability. This review thoroughly evaluates recent progress in the synthesis and application of such catalysts, highlighting Ti–Cu–Zn nanostructures as a representative case study. We examine synthesis approaches—including hydrothermal, biosynthesis, precipitation, and spray-based methods, with additional insight into sol–gel and other less commonly applied techniques—with emphasis on their suitability for constructing layered and multicomponent heterostructures. Mechanistic aspects of photocatalysis, Fenton and Fenton-like processes, adsorption, and electrochemical routes are discussed, with particular focus on charge separation, reactive oxygen species (ROS) generation, and pollutant-specific degradation pathways. Comparative performance metrics against antibiotics, pesticides, dyes, and fertilizers are analyzed, alongside considerations of leaching, reusability, and scale-up potential. Importantly, while significant progress has been made for organic micropollutants, applications in heavy metal remediation remain scarce, highlighting an urgent research gap. By situating Ti–Cu–Zn systems within the broader class of multicomponent catalysts, this review not only synthesizes current advances but also identifies opportunities to expand their role in sustainable wastewater management, including field deployment, regulatory compliance, and integration into decentralized treatment systems. Full article

To investigate the impacts of the continuous application of urban sewage sludge on heavy metal pollution risks in wine grape orchards, this study conducted a five-year field plot experiment using wine grapes as the test crop. The experimental design included three sludge application rates and a control without sludge application. Soil physicochemical properties, the single-factor and integrated pollution indices (PI and NIPI) of heavy metals, potential ecological risk indices (EI and RI), and the safe application duration of sludge were analyzed. The results suggest that sludge application significantly increased soil organic matter, total nitrogen, total phosphorus, and available phosphorus by 39.99–46.56%, 59.37–73.69%, 83.57–143.19%, and 88.79%, respectively, while reducing soil bulk density by 8.70–27.92%. The PI and EI of Cd exhibited significant linear increases with the duration of sludge application, with annual increments of 0.010 and 0.31, respectively. Hg was influenced by both the application rates and duration, with annual increments of 0.013 and 0.52 for the PI and EI, respectively. These two elements collectively drove overall increases of 7.31–24.96% in NIPI and 32.51–59.90% in RI, with mean annual increases of 0.0064 and 0.84, respectively. In contrast, Cr, Pb, and As showed no significant changes. Based on the calculated environmental capacities of Cd and Hg, the safe application durations were estimated to be 46.99–126.93 and 48.58–131.21 years, respectively. These results demonstrate that under the current application intensity, sludge can improve soil fertility in the short term with controllable ecological risks. However, considering their potential environmental risks, the continuous accumulation of Cd and Hg necessitates vigilance. Full article

Urease-producing bacteria (UPB) have great potential for the bioremediation of heavy-metal pollution through biomineralization and adsorption. In this study, a strain of UPB, C7-12, was isolated from heavy-metal-contaminated soil in a lead–zinc mining area and identified as Serratia marcescens. The heavy-metal removal ability, influencing factors, and precipitation mode of this UPB strain in solution were investigated. The cadmium (Cd) removal rate in a Cd (1 mg/L) solution from C7-12 reached 85%, and pH was the main influencing factor. With urea mediation, S. marcescens C7-12 biomineralizes the Cd²⁺ in solution to form CdCO₃ and removes it through extracellular precipitation and surface adsorption. Furthermore, the removal rates of Cd²⁺, Pb²⁺, Zn²⁺ and Cu²⁺ in solution by S. marcescens C7-12 were 33–65%, 28–32%, 22–49%, and 38–44%, respectively. The precipitation mode involves coprecipitation of multiple heavy metals to form a mineral. These heavy metals are adsorbed on the surface of bacteria through the participation of carboxyl, amino, and phosphate functional groups and extracellular polymeric substances. Therefore, S. marcescens C7-12 has strong biomineralization and adsorption capacity for heavy-metal ions in solution, which can provide potential resources for the bioremediation of heavy-metal-contaminated soil and water. Full article

Around eight million people—mainly in cities—die prematurely from pollution-related diseases; thus, studies of urban dust have become increasingly relevant over the last two decades. In this study, an assessment of heavy metal and metalloid contamination in urban dust was conducted in downtown Murcia, Spain. The objectives were to evaluate the level of contamination and the associated health risks, both with a spatially explicit focus. One hundred and twenty-eight urban dust samples were collected, each from a 1-square-meter area, using plastic tools to prevent contamination. The dust was dried and weighed, then acid-digested before analysis via inductively coupled plasma mass spectrometry. Corresponding maps were then generated using a geographic information system. The elements analyzed in the urban dust (with their median concentrations, given in mg/kg) were As (2.14), Bi (14.06), Cd (0.38), Co (1.88), Cr (71.17), Cu (142.60), Fe (13,752), Mn (316.64), Mo (3.90), Ni (21.94), Pb (106.27), Sb (6.54), Se (4.34), Sr (488.08), V (28.05), and Zn (357.33). The sequence of median concentrations for the analyzed elements was Fe > Sr > Zn > Mn > Cu > Pb > Cr > V > Ni > Bi > Sb > Se > Mo > As > Co > Cd. The pollution assessment reveals that the city is moderately polluted. Using local background levels, the elements with median values exceeding the threshold for considerable contamination were As, Cu, Pb, Sb, Se, and Zn. Using the global background level, the elements with median values exceeding the threshold for considerable contamination were Bi, Cu, Mo, Pb, Sb, Se, and Zn. The median value of the sum of the hazard index (1.82) indicates a risk to children’s health. The hazard index revealed that 43% of the sites pose a relative risk to children. In contrast to previous global studies, the present research provides a multi-scale assessment of urban pollution and health risks. Pollution is evaluated by metal, city, zone, and site, while health risks are assessed by metal, city, and site. We recommend a strategy for both local authorities and residents. Full article

In Guangxi, China, the area used to plant sugarcane is growing in order to meet the Fourteenth Five-Year Plan’s objective of sugar self-sufficiency (2021–2025). Comprehensive soil heavy metal data are necessary for growing area expansion in order to inform farmers and policymakers. Here, we analyzed soil samples from ten sugarcane-growing counties/districts of Guangxi by employing four different risk assessment indices. Our results indicate that the studied soils are moderately to strongly acidic and are deficient in soil organic matter (<6 g/kg). Single-factor pollution index evaluation revealed detectable heavy metal pollution, with Cd present above reference levels in all ten areas, Cr in six, Pb in four, As in two, and Hg in two areas. The Nemerow comprehensive pollution index indicated that the overall soil pollution level was mild, except for Jiangzhou district (moderate). The geo-accumulation index revealed significant anthropogenic enrichment, with severe Cr pollution (Igeo > 3) across all regions and Pb and As contamination ranging from moderate to severe, particularly in Jiangzhou district. Contrastingly, Cd and Hg showed no significant enrichment (Igeo < 0) relative to the local background, though their sources require further investigation. The potential ecological risk assessment showed a high risk, specifically from As in Jiangzhou district, which was the only area showing a moderate comprehensive potential ecological risk. A significant positive correlation was found between the total and bioavailable contents of all five heavy metals, whereas soil pH and organic matter were significantly negatively correlated with the bioavailability of Cr and Pb, but positively correlated with As and Hg. The availability of Cd, however, was independent of pH and OM, suggesting the influence of other, unmeasured geochemical factors. These results highlight specific and localized environmental risks that may require targeted management to ensure agricultural safety, ecosystem health, and sustainable sugarcane production. Full article

Soil heavy metal contamination poses significant risks to ecological safety and human health, particularly in rapidly industrializing cities. Effectively identifying pollution sources is crucial for risk management and remediation. GIS coupled with data mining techniques, provide a powerful tool for quantifying and visualizing these sources. This study investigates the concentration, spatial distribution, and sources of heavy metals in urban soils of Bengbu City, an industrial and transportation hub in eastern China. A total of 139 surface soil samples from the urban core were analyzed for nine heavy metals. Using integrated GIS and PCA-APCS-MLR data mining techniques, we systematically determined their contamination characteristics and apportioned sources. The results identified widespread Hg enrichment, with concentrations exceeding background levels at all sampling sites, and a Cd exceedance rate of 28.06%, leading to a moderate ecological risk level overall. Spatial patterns revealed significant heterogeneity. Quantitative source apportionment identified four primary sources: industrial source (37.1%), which was the dominant origin of Cr, Cu, and Ni, primarily associated with precision manufacturing and metallurgical activities; mixed source (26.7%) governing the distribution of Mn, As, and Hg, mainly from coal combustion and the natural geological background; traffic source (22.3%) significantly contributing to Pb and Zn; and a specific cadmium source (13.9%) potentially originating from non-ferrous metal smelting, electroplating, and agricultural activities. These findings provide a critical scientific basis for targeted pollution control and sustainable land-use management in analogous industrial cities. Full article

Sewage sludge (SS) management and wastewater (WW) treatment remain among the most critical environmental challenges. The pyrolysis of sewage sludge to produce biochar (BC) represents a sustainable and circular strategy for waste valorization and pollution mitigation. This scoping review provides a comprehensive overview of BC derived from SS (BCxSS), with particular emphasis on how pyrolysis conditions affect key physicochemical characteristics such as yield, ash content, pH, surface area, and functional groups. Although substantial research has focused on the removal of heavy metals and organic pollutants using BCxSS, far less attention has been directed toward its potential for pathogen adsorption and inactivation, revealing a notable research gap. Recent studies highlight BCxSS as a versatile material with considerable promise in adsorption and catalysis. However, its application in pathogen removal remains insufficiently investigated, underscoring the need for further investigation into sorption mechanisms and biochar–microbe interactions. Full article

As plastic and heavy metal pollution continue to escalate, the co-occurrence of microplastics and heavy metals in the environment poses significant threats to ecosystems and human health. This study was designed to explore the combined effects of polyethylene microplastics (PE-MPs) and cadmium (Cd) pollution on wheat seedlings, focusing on antioxidant enzyme activity and Cd bioaccumulation. At low concentrations of PE ($1\mathrm{mg}·{\mathrm{L}}^{-1}$), peroxidase (POD) activity in wheat shoots slightly increased without significance, while at higher concentrations ($50\mathrm{mg}·{\mathrm{L}}^{-1}$ and $100\mathrm{mg}·{\mathrm{L}}^{-1}$) of PE, POD activity was significantly inhibited compared to $0\mathrm{mg}·{\mathrm{L}}^{-1}$ PE treatment. At Cd exposure activity, with POD activity in the shoots increasing by 73.7% at $50\mu \mathrm{mol}·{\mathrm{L}}^{-1}$${\mathrm{Cd}}^{2+}$ compared to $0\mu \mathrm{mol}·{\mathrm{L}}^{-1}$ Cd treatment. When wheat seedlings were exposed to a combination of $50 \mathrm{mg}·{\mathrm{L}}^{-1}$ PE and Cd at different concentrations Cd, significant differences in POD activity were observed in the shoots compared to the control group, showing an upward trend with increasing Cd concentration. However, the addition of PE suspension generally reduced POD activity in wheat shoots compared to Cd treatment alone. Specifically, the presence of $50\mathrm{mg}·{\mathrm{L}}^{-1}$ PE did not significantly alter POD activity in the wheat shoots ($p>0.05$). Furthermore, exposure to different concentrations of Cd resulted in a general increase in POD activity of roots, with significant differences observed at $5\mu \mathrm{mol}·{\mathrm{L}}^{-1}$ and $25\mu \mathrm{mol}·{\mathrm{L}}^{-1}$ Cd ($p<0.05$). Regarding Cd bioaccumulation, at Cd low concentrations ($1\mu \mathrm{mol}·{\mathrm{L}}^{-1}$ and $5\mu \mathrm{mol}·{\mathrm{L}}^{-1}$), PE significantly promoted Cd accumulation in the shoots. However, at high Cd concentrations ($50\mu \mathrm{mol}·{\mathrm{L}}^{-1}$), PE microplastics reduced Cd accumulation in the shoots but promoted its accumulation in the roots.These results suggest that PE microplastics influence the bioavailability of Cd, mitigating the toxic effects of high Cd concentrations. This paper scientifically elucidates the ecotoxicological effects of co-contamination for microplastics and heavy metals, also their potential impacts on agricultural production are discussed. Full article