Search Results (4,128)

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

Background/Objective: Prostate cancer (PCa) is the leading cause of death in the ageing male population across the globe, and trace metals have garnered much attention due to their sometimes-dual role in cellular mechanisms, as such contribute to the development and progression of prostate cancer. Methods: This review consolidates the results of case-control studies that investigated the concentrations of certain trace metals—Arsenic (As), cadmium (Cd), mercury (Hg), manganese (Mn), nickel (Ni), lead (Pb), selenium (Se), and zinc (Zn) in various biological samples. Results: There are decreased concentrations of Se and Zn and increased Cd concentrations in samples of PCa patients when compared to healthy controls. As, Hg, Ni, and Pb concentrations have proven to be insignificant. Conclusions: There are other variables to consider and limitations that need to be investigated in studies of this nature; however, the results have been consistent in that increased exposure to toxic metals such as Cd, along with a deficiency in protective essential nutrients like Zn and Se, tends to produce a prostatic environment. 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

Glaesserella parasuis (G. parasuis) is a key pathogen responsible for swine respiratory disease, and the development of broadly protective vaccines is hampered by its high antigenic diversity. The iron-acquisition protein TbpB is a conserved vaccine candidate, but the cellular immune responses it elicits, particularly T-cell subset dynamics during immunization and challenge, remain insufficiently defined. This study characterized these responses after oral immunization of colostrum-deprived piglets with the TbpB^Y167A mutant. Ten colostrum-deprived piglets were allocated to immunized and non-immunized (PBS) groups, immunized at days 15 and 30 of life and subsequently challenged with G. parasuis (45 days old); peripheral blood mononuclear cells were collected at baseline, after each immunization, and at 1 and 3 days post-infection. Multiparametric flow cytometry was used to quantify major leukocyte subsets and T-cell phenotypes defined by sIgM, CD172a, CD3, TCRγδ, CD8α/β, CD4 and CD27 expression. Booster immunization induced significant expansion of B cells (p < 0.01), TCRγδ T cells (p < 0.01), CD8⁺ αβ T cells (p < 0.001) and CD4⁺ memory T cells (p < 0.01) in immunized piglets compared with controls. After challenge, CD8⁺ cytotoxic T cells in immunized animals rapidly shifted from naïve to memory phenotypes, peaking at 48–72 h (p < 0.01). These biphasic T-cell dynamics are consistent with the protective efficacy previously demonstrated for this vaccine in colostrum-deprived piglets, and support a key contribution of TCRγδ, CD8⁺ cytotoxic and CD4⁺ memory T cells to immunity against G. parasuis and to the design of next-generation vaccines. 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

Soil contamination by heavy metals (HMs) threatens crop productivity, food safety, and ecosystem health, especially in intensively cultivated Mediterranean regions. This study investigated the influence of soil HM contamination on nutrient uptake, photosynthetic traits, and metal bioaccumulation in avocado (Persea americana Mill.) orchards. Twenty orchard sites were sampled, collecting paired soil and mature leaf samples. Soil physicochemical properties and HM concentrations were determined, while leaves were analyzed for macro- and micronutrients, photosynthetic pigments, and metal contents. Bioaccumulation Factors (BAFs) were computed, and multivariate analyses (Principal Component Analysis (PCA), Hierarchical Cluster Analysis (HCA), Linear Discriminant Analysis (LDA), and Partial Least Squares Regression (PLSR)) were applied to assess soil–plant relationships, complemented by Monte Carlo simulations to quantify probabilistic contamination risks. Results revealed substantial inter-site variability, with leaf Cd and Pb concentrations reaching 0.92 and 3.54 mg/kg, and BAF values exceeding 1 in several orchards. PLSR models effectively predicted leaf Cd (R² = 0.789) and Pb (R² = 0.772) from soil parameters. Monte Carlo simulations indicated 15–25% exceedance of FAO/WHO safety limits for Cd and Pb. These findings demonstrate that soil metal accumulation substantially alters avocado nutrient balance and photosynthetic efficiency, highlighting the urgent need for site-specific soil monitoring and sustainable remediation strategies in contaminated orchards. Full article

The present study investigates the potential of poplar (Populus spp.) biomass from phytoremediation plantations as a feedstock for downdraft fixed bed gasification. The biomass was characterized in terms of moisture, ash content, elemental composition (C, H, N, O), and calorific values (HHV and LHV), confirming its suitability for thermochemical conversion. Gasification tests yielded a volumetric syngas production of 1.79 Nm³ kg⁻¹ biomass with an average composition of H₂ 14.58 vol%, CO 16.68 vol%, and CH₄ 4.74 vol%, demonstrating energy content appropriate for both thermal and chemical applications. Alkali and alkaline earth metals (AAEM), particularly Ca (273 mg kg⁻¹) and Mg (731 mg kg⁻¹), naturally present enhanced tar reforming and promoted reactive gas formation, whereas heavy metals such as Cd (0.27 mg kg⁻¹), Pb (0.02 mg kg⁻¹), and Bi (0.01 mg kg⁻¹) were detected only in trace amounts, posing minimal environmental risk. The results indicate that poplar pruning residues from phytoremediation sites can be a renewable and sustainable energy resource, transforming a waste stream into a process input. In this perspective, the integration of soil remediation with syngas production constitutes a tangible model of circular economy, based on the efficient use of resources through the synergy between environmental remediation and the valorization and sustainable management of marginal biomass—i.e., pruning residues—generating environmental, energetic, and economic benefits along the entire value chain. Full article

This study evaluated the geochemical contamination and ecological risk of metal(oid)s (As, Cd, Cr, Cu, Pb, Hg, and Zn) in sediments from four sites within a section of the Madre de Dios River, Peru—an area affected by artisanal alluvial gold mining and with limited prior research that considers its local geochemical complexity. Sediment samples were collected between 2013 and 2020, spanning seven river flood seasons and four low river flow seasons. Background values were estimated using ProUCL 5.2, considering local climatic and geological conditions. Environmental quality indices revealed that sediments in the studied river section were mainly contaminated and exhibited high ecological risk due to Hg, used in gold amalgamation, which showed peak values in 2013 and subsequently declined to moderate levels. Cd exhibited contamination and ecological risk until 2016, with non-detectable values thereafter, while As, Cu, Cr, Pb, and Zn showed low environmental alteration. Factor analysis and principal component analysis indicated a natural origin for Cu, Cr, Pb, and Zn, whereas Hg showed an anthropogenic source linked to mining. Elevated concentrations of Hg, Cr, and Zn during the river flood season highlight the influence of hydrological dynamics on contaminant mobilization within these sites of the river section. Full article

This study examines the post-war evolution of groundwater quality in Mosul by evaluating the seasonal and annual behavior of physicochemical parameters and heavy metals, while differentiating the responses of shallow and deep aquifers and determining whether groundwater conditions during the early recovery period (2022–2023) indicate natural improvement or continued deterioration. Groundwater samples from shallow (W5–W8) and deep (W1–W4) wells were collected across four sampling campaigns representing both wet and dry seasons. Shallow wells exhibited marked seasonal increases, with pH, electrical conductivity (EC), and total dissolved solids (TDS) increasing during the dry season, driven by evaporation and limited recharge. Nutrient concentrations (PO₄³⁻, NO₃⁻, SO₄²⁻) showed similar seasonal rises but declined slightly in 2023 following reduced rainfall. Heavy metals (Cd, Pb, Cr, Ni, Zn) displayed pronounced seasonal peaks in the wet season and higher annual averages in 2023, suggesting delayed mobilization from contaminated soils. In contrast, deep wells remained relatively stable, reflecting the buffering capacity of deeper geological formations. Statistical analyses supported these patterns: shallow wells demonstrated significant seasonal variability (p < 0.05) across most parameters, whereas deep wells exhibited limited seasonal differences and no significant annual variation. These findings indicate that shallow aquifers—particularly those constructed during the conflict—are more vulnerable to post-war environmental stresses, while deeper aquifers retain greater resilience. Overall, the study underscores progressive degradation of shallow groundwater linked to post-conflict conditions and highlights the need for sustained monitoring, stricter regulation of groundwater use, and targeted remediation strategies to protect drinking and irrigation resources in conflict-affected regions. These insights are crucial for developing sustainable groundwater management strategies in post-war urban environments. Full article

Tolerance to metals develops independently across plant species and even among populations of the same species under strong environmental pressure. This study compares the morphology and leaf anatomy of Dianthus carthusianorum L. originating from a Zn–Pb waste dump (metallicolous ecotype, M) and from unpolluted areas (non-metallicolous ecotype, NM), exposed to toxic concentrations of Cd, Pb, or Zn under chronic (field) and acute (hydroponic) metal stress. The aim was to identify leaf anatomical adaptations that support growth of the M ecotype in metal-polluted environments and to assess structural changes induced by acute exposure in both ecotypes. In both ecotypes, metal exposure caused alterations of mesophyll cells and the formation of abundant calcium oxalate (CaOx) crystals. Two oxalate forms were determined: insoluble (CaOx crystals) and soluble oxalates, with the former predominating. Following metal treatment, the M ecotype accumulated nearly twice as much of both forms as the NM ecotype, indicating a key role of oxalates in metal detoxification via precipitation of excess metal ions as metabolically inactive CaOx. Interestingly, elevated CaOx levels were also observed in M ecotype leaves grown under control (no metal application) conditions, suggesting a genetically fixed adaptation to metal-rich environments. Full article

This study investigates the accumulation potential of Brassica napus L. and Zea mays L. cultivated on soils contaminated with Zn, Cd, Cu and Pb, using HEDTA—Hydroxyethyl Ethylenediamine Triacetic Acid—to enhance metal mobility. The research addresses a gap in the literature regarding the dual-purpose use of energy crops for assisted phytoextraction and bioenergy recovery. Two pot experiments were conducted on soils of different textures, with HEDTA applied at 2.5 and 5 mmol·kg⁻¹. Metal concentrations in soil and plant tissues were measured, and indices such as the geoaccumulation index (Igeo), bioconcentration factors (BCF), translocation factor (TF), metal tolerance index (MTI), crop growth rate (CGR) and higher heating value (HHV) were calculated. Results showed that HEDTA significantly increased Cd and Zn mobility, leading to higher accumulation in rapeseed shoots. Maize demonstrated phytostabilization by retaining metals in roots. Rapeseed biomass exhibited a higher HHV (up to 20.6 MJ·kg⁻¹) and greater carbon and hydrogen content, indicating suitability for thermochemical conversion. Maize, with lower ash content, showed potential for bioethanol production. The findings support the integration of chelate-assisted phytoextraction with energy recovery from biomass. Full article

Dry eye disease is a common condition in which tear production or quality is insufficient to lubricate the eyes properly. Standard treatment usually involves lubricating eye drops. In this study, we assessed the human health risks, including both non-carcinogenic and carcinogenic effects, associated with long-term exposure to the chemical elements arsenic (As), cadmium (Cd), cobalt (Co), iron (Fe), nickel (Ni), lead (Pb), and zinc (Zn) in eye drops used in Brazil. The results indicated that the Co concentration (1.1048 mg/kg) in the eye drops sample 5 exceeded the limit established by the ICH Q3D (R2) guideline for parenteral products (0.5000 mg/kg). Additionally, As levels in eye drop samples 2, 8–10, 12, 13, and 16, as well as Cd levels in samples 2, 3, 8–10, and 12, exceeded the limits established by the Brazilian Pharmacopoeia for parenteral administration (0.0500–0.0532 mg/kg). The main health risk appears to come from oral exposure, as the drug can drain into the nasal cavity via the nasolacrimal duct and then be absorbed through the gastrointestinal tract. While none of the tested eye drops posed non-carcinogenic risks, carcinogenic risks from oral exposure to As and Cd were identified, with overall risk levels exceeding acceptable thresholds. These findings emphasize the need for strict regulation and continuous monitoring of these products to reduce health risks and prevent long-term damage. Full article

Heavy metals (arsenic, cadmium, and lead) remain one of the most common and complex environmental problems worldwide. Accordingly, there is a growing need for eco-friendly and affordable materials derived from agricultural waste for the removal of heavy metals from contaminated water. This study aims to demonstrate how biodegradable pineapple leaf cellulose (PLC) can be used effectively in the remediation of heavy metals. The PLC adsorbent was prepared by treating it with ethyl alcohol (EtOH, 99.5%), calcium chloride (CaCl₂), and 0.8 M sodium hydroxide. A scanning electron microscope equipped with energy-dispersive X-ray spectroscopy (SEM-EDS) and Fourier transform infrared spectroscopy (FT-IR) was used to investigate the surface of the adsorbent. Inductively coupled plasma mass spectrometry (ICP-MS) was employed to measure the concentration of metals before and after adsorption. Removal of metal ions (As⁵⁺, Cd²⁺, and Pb²⁺) by PLC was investigated under varying conditions, including pH, contact time, and adsorbent dosage. The analysis of cellulose composite revealed significant potential for adsorption of heavy metals such as As⁵⁺, Cd²⁺, and Pb²⁺. The highest removal efficiency of heavy metal ions was detected at a pH ranging from 3 to 7. The biosorption order of PLC at pH 6 was Pb²⁺ > Cd²⁺ > As⁵⁺ with 99.53% (63.45 mg/g), 98.44% (37.23 mg/g), and 42.40% (16.27 mg/g), respectively. After 120 min, the equilibrium of the adsorption process was reached for As⁵⁺, Cd²⁺, and Pb²⁺. FT-IR characterization discovered an increased abundance of functional groups on the adsorbent. The SEM-EDS analysis confirmed the occurrence of elements on the surface of PLC. The study revealed that the use of PLC is an innovative method for removing heavy metals from aquatic milieus, a potential resource for eco-friendly and affordable wastewater treatment. Full article

This study evaluated the effects of domestic cooking methods (pan-frying, smoking, and grilling) on the concentrations of elements of toxicological concern and essential elements (Cd, Cr, Cu, Fe, Mn, Ni, Zn, and Pb) in the traditionally consumed Black Sea bluefish (Pomatomus saltatrix). The investigation also included an assessment of the associated health risks and benefits by calculating carcinogenic and non-carcinogenic effects as well as benefit–risk ratios. Toxic heavy metals such as Cd, Ni, and Pb were found to be below the maximum residual limits (MRLs) established by relevant food safety authorities. Cooking generally led to increased concentrations of both essential and toxic elements compared to raw samples, with the highest increases observed in grilled and smoked samples. Furthermore, evaluations of (a) estimated weekly intakes (EWIs), (b) target hazard quotients (THQs) for Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn, and (c) hazard quotient ratios for essential fatty acids (HQ_EFA) relative elements indicated that consumption of these cooked bluefish species does not pose significant health risks to consumers. Full article