Search Results (359)

Heavy metals in farmland soils pose severe threats to agricultural productivity and food safety. To investigate contamination in the soil–wheat/corn system, 24 sets of adjacent farmland soil, wheat, and corn plant samples were collected near metal smelting facilities in Jinchang City, a typical urban oasis in northwestern China. Concentrations of Ni (nickel), Cu (copper), and Co (cobalt) were measured. Results indicated mean soil concentrations of 143.66 mg kg⁻¹ (Ni), 130.00 mg kg⁻¹ (Cu), and 24.04 mg kg⁻¹ (Co), all exceeding background values for Gansu Province, confirming that the sampling sites exhibit varying degrees of contamination with Ni, Cu, and Co. Correlation analyses revealed strong intermetal relationships (Ni, Cu, Co; p < 0.01), while spatial distribution patterns showed that Ni in wheat and corn grains closely mirrored soil Ni distribution. The bio-concentration factor (BCF) for wheat roots surpassed that of corn roots, highlighting wheat’s greater susceptibility to heavy metal uptake. Heavy metal levels in crop organs exceeded limits set by the Safety Guidelines for Feed Additives. Geo-accumulation indices and potential ecological risk assessments demonstrated substantial metal accumulation and varying ecological risks, with contamination levels ranked as Cu > Ni > Co. Non-carcinogenic hazard indices indicated elevated health risks for children consuming locally grown wheat and corn. This study provides a scientific foundation for crop rotation strategies and soil remediation in the region. Full article

Technological proliferation relies on critical elements such as rare earth elements (REEs) and raises environmental problems associated with raw material extraction, industrial manufacturing, and the informal management of the growing e-waste. Algae are good bioindicators of contamination and have shown promise as biosorbents for remediating metal-contaminated environments. However, the effects of REEs on algae are still poorly documented and understood. This study investigated the uptake of yttrium (Y)—one of the most frequently used REEs, particularly in fluorescent lamps—by Ulva sp., as well as its effects on total chlorophyll content, relative growth rate, and biochemical performance. The algae were exposed to Y for 72 h at environmentally relevant concentrations, including levels found in e-waste leachates (0.5, 5.0, 50, and 500 mg/L). Ulva sp. removed 86% of Y within 72 h, with a bioconcentration factor of up to 621. EDTA analysis revealed that over 90% of yttrium was retained on the algal surface. SEM-EDS mapping showed crystal structures on the algae where Y was present. While the relative growth rate was unaffected by the tested Y gradient, photosynthesis was significantly impaired at 500 mg/L. Despite the activation of defence mechanisms, cell damage was observed at most Y concentrations tested, highlighting the potential risks associated with the presence of REEs in aquatic environments. Full article

Danube Delta (DD), an ecologically vulnerable site, together with fish populations, which are significant food resources, are largely exposed to heavy metal contamination. This study was developed in the Babina–Cernovca sector of DD in September 2023. Zinc (Zn), and iron (Fe) were identified in water, while copper (Cu), iron (Fe), and manganese (Mn) were in sediments (mud). Proximate composition of the muscle tissues of eight fish species identified in the area was assessed. The muscle was also tested to identify heavy metals contamination. The contamination degree was assessed using bioaccumulation and bioconcentrations factors. The relation between nutritional parameters and metals was tested using bivariate and multivariate analyses. Samples were analyzed by specific laboratory tests, and data were processed using ANOVA, Spearman correlation, Principal Component Analysis (PCA), and hierarchical clustering. S. erythrophthalmus, C. gibelio, and A. alburnus have the highest metal bioaccumulation capacity, exhibiting species-specific accumulation patterns. PCA and clustering analysis reflect the influence of species and environmental factors on heavy metal accumulation in fish tissue. The study integrates the heavy metals content with nutritional parameters in fish muscular tissue, using bivariate and multivariate analysis for assessing fish vulnerability to heavy metals exposure in the Danube River. Full article

To explore strategies for the safe utilization of farmland co-contaminated with cadmium (Cd) and lead (Pb), this field study systematically evaluated the impacts of humic acid (HA) and potassium fulvate (PF) at different application rates (0, 1500, 3000, and 4500 kg·ha⁻¹) on the growth, yield, and translocation of Cd and Pb within the soil–plant system of maize (Zea mays L.). The results showed that while HA and PF did not significantly alter total soil Cd and Pb concentrations, they markedly reduced their bioavailable fractions. This mitigation of heavy metal phytotoxicity significantly promoted maize growth and yield, with the high-dose HA treatment increasing yield by a maximum of 32.9%. Both amendments dose-dependently decreased Cd and Pb concentrations, bioconcentration factors (BCF), and translocation factors (TF) in all maize tissues, particularly in the grains. At equivalent application rates, PF was slightly more effective than HA in reducing heavy metal concentrations in the grains. Notably, a significant positive correlation was observed between Cd and Pb concentrations across all plant parts, confirming a synergistic accumulation and translocation mechanism. This synergy provides a physiological explanation for the broad-spectrum immobilization efficacy of these humic substances. In conclusion, applying HA and PF presents a dual-benefit strategy for increasing yield and reducing risks in Cd- and Pb-contaminated farmlands. This study proposes a differentiated application approach: PF is the preferred option when ensuring food-grade safety is the primary goal, whereas high-dose HA is more advantageous for maximizing yield in soils with low-to-moderate contamination risk. Full article

Understanding heavy metal behavior in arid saline soils is critical for phytoremediation in degraded lands. This study investigated metal distribution and plant enrichment in the Tarim Basin using 323 soil and 55 plant samples (Populus euphratica, Tamarix ramosissima, cotton, jujube). Analyses included redundancy analysis (RDA) and bioconcentration factor (BCF) assessments. Key findings reveal that elevated salinity (total salts, TS > 200 g/kg) and alkalinity (pH > 8.5) immobilized As, Cd, Cu, and Zn. Precipitation and competitive leaching reduced metal mobility by 42–68%. Plant enrichment strategies diverged significantly: P. euphratica hyperaccumulated Cd (BCF = 1.59) and Zn (BCF = 2.41), while T. ramosissima accumulated As and Pb (BCF > 0.05). Conversely, cotton posed Hg transfer risks (BCF = 2.15), and jujube approached Cd safety thresholds in phosphorus-rich soils. RDA indicated that pH and total salinity (TS) jointly suppressed metal bioavailability, explaining 57.6% of variance. Total phosphorus (TP) and soil organic carbon (SOC) enhanced metal availability (36.8% variance), with notable TP-Cd synergy (Pearson’s r = 0.42). We propose a dual-threshold management framework: (1) leveraging salinity–alkalinity suppression (TS > 200 g/kg + pH > 8.5) for natural immobilization; and (2) implementing TP control (TP > 0.8 g/kg) to mitigate crop Cd risks. P. euphratica demonstrates targeted phytoremediation potential for degraded saline agricultural systems. This framework guides practical management by spatially delineating zones for natural immobilization versus targeted remediation (e.g., P. euphratica planting in Cd/Zn hotspots) and implementing phosphorus control in high-risk croplands. Full article

Untreated tannery wastewater (UTW) poses unprecedented threats to the aquatic and irrigation systems due to severely limited pollution removal efficiency (RE %) by the limited capacity and design of wastewater treatment plants in developing countries. An exploitation of treatment wetlands (TWs) like floating treatment wetlands (FTWs) face hydraulic performance and survivability and establishment challenges of transplanted hydrophytes in the severely toxic UTW. Such challenges were overcome by designing a horizontal flow floating treatment wetland (HFFTW) and diluting UTW at 0, 25, 50, and 75 with harvested rainwater (HRW), viz. UTW:HRW (% v:v) for lowering phytotoxicity to the phytotolerance range of the tested hydrophytes, viz. Eichhornia crassipes (EC) and Pistia stratiotes (PS) in the HFFTW, i.e., EC-HFFTW and PS-HFFTW. Both hydrophytes showed heavy metals’ translocation factor being ≥1, i.e., and acted as excellent hyperaccumulators of heavy metals. The average metal RE (%) was 64 (Cr), 61 (Cd), 45 (Pb), 44 (Cu), and 50.1 (BOD) for E. crassipes, and 44 (Cr), 54 (Cd), 42.2 (Pb), 42 (Cu), and 40 (BOD) for P. stratiotes. Significant reductions in the organic pollution load witnessed by significant drops in BOD and COD made UTW a safer irrigation medium for Petunia hybrida while inducing an increase in the bioconcentration factor (BCF) of PS and EC. The study concluded that the designed HFFTW showed significantly greater RE (%) and yield of reclaimed water than conventional FTWs based on its hydraulic performance. The design HFFTW carries a field scale application capacity for improvising treatment efficiency of the combined effluent plant of KTWMA (Kasur Tannery Waste Management Agency), Kasur, Pakistan. Full article

Mercury (Hg) pollution from artisanal and small-scale gold mining (ASGM) is a global environmental and public health concern. In Indonesia, ASGM remains widespread, yet assessments of multimedia contamination and health risks are limited. This study quantified Hg concentration in water, sediment, soil, fish, and cassava to evaluate environmental pollution and potential health risks in Waluran, Sukabumi, Indonesia. Mercury concentration in ASGM was higher than in the reference area, especially in fish (median: 4.76 mg/kg dw), cassava leaves (median: 15.7 mg/kg dw), and tailing sediments (median: 171 mg/kg dw). A remarkably high Hg concentration (9760 mg/kg dw) was detected in soil from amalgam-burning spots. An elevated Hg concentration was observed in the reference area, suggesting widespread contamination and potential for long-range dispersion. Over 85% of ASGM samples were categorized as heavily to extremely contaminated by the geo-accumulation index (I_geo). Bioaccumulation assessment indicated a high bioconcentration factor (BCF) in fish and moderate bioaccumulation factor (BAF) in cassava roots. Hazard Quotients (HQ) were greater than 1 for most exposure pathways in both adults and children, with the greatest risk deriving from cassava leaf consumption. These findings indicate severe Hg contamination within ASGM-affected communities and underscore the urgent need for public health interventions, environmental monitoring, and strengthened regulations to reduce Hg exposure in Indonesia. Full article

Purpose: This study aimed to investigate the migration and distribution characteristics of trace elements in the soil–tea system in the Cuiya tea area of Meitan County, Guizhou Province. Methods: The contents of trace elements (Cd, Fe, La, Mg, Mn, Ni, Se, Pr, Sm, Zn) in tea and soil samples were determined by inductively coupled plasma emission spectrometry (ICP-OES). Results: The average contents of heavy metals in soil and tea from Meitan County were below the Chinese national standards, while also meeting the criteria for selenium enrichment. Within the soil–tea system, Mn in tea leaves exhibited a significant negative correlation with soil Mn, while Cd showed a significant positive correlation with soil Cd. This pattern was consistent across both the topsoil and subsoil. The tea plants exhibited a high enrichment capacity for Mn, Mg, and Zn, but a low capacity for Sm, Fe, and Cd. Among the studied areas, the enrichment effect was most pronounced in SL, XH, and MJ towns. Conclusions: Significant spatial variations were observed in the concentrations of trace elements in both tea and soil across the Meitan tea area. This study provides a scientific basis for understanding the enrichment and migration of trace elements within the soil–tea system of Meitan County, Guizhou, and for tracing the geographical origin of its tea. Full article

Mining and metallurgical activities negatively impact ecosystems due to the release of potentially toxic elements (PTEs). This study assesses PTE pollution and accumulation in native plant species that have spontaneously colonized a historical mining site (Michaly, site A) and a nearby metallurgical smelter site (Varvara, site B) on the Lavreotiki Peninsula, Attika, Greece. Soils were analyzed for As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sb, and Zn. A total of 89 native plant taxa across 28 families were identified. The aerial parts from dominant species were analyzed for PTE concentrations, and bioconcentration factors (BCFs) were calculated. One-way ANOVA and principal component analysis (PCA) using R were used for statistical evaluation. Soils at both sites showed elevated As, Cd, Cr, Cu, Ni, Pb, Sb, and Zn; Mn was high only at site B, while Co and Fe remained at background levels. Several plant species, especially at Michaly, had elevated concentrations of As, Cd, Co, Cr, Fe, Pb, Sb, and Zn in their aerial parts. BCFs indicated general PTE exclusion from aerial parts, particularly at site B. Native vegetation on these contaminated sites shows resilience and PTE exclusion, highlighting their potential for phytoremediation, especially phytostabilization, and ecological restoration in similarly polluted Mediterranean environments. Full article

This study provides a comprehensive six-year assessment (2018–2023) of heavy metal contamination in the Romanian Black Sea sector, integrating data from seawater, surface sediments, and benthic mollusks. Sampling was conducted across a broad spatial gradient, including transitional, coastal, shelf, and offshore waters beyond 200 m depth. Concentrations of six potentially toxic metals, including cadmium (Cd), lead (Pb), nickel (Ni), chromium (Cr), copper (Cu), and cobalt (Co), were measured to evaluate regional variability, potential sources, and ecological implications. Results indicate some exceedances of regulatory thresholds for Cd and Pb in transitional and coastal waters, associated with Danube River input and coastal pressures. Seabed substrate analysis revealed widespread enrichment in Ni, moderate levels of Cr, and sporadic Cd elevation in Danube-influenced areas, along with localized hotspots of Cu and Pb near port and industrial zones. Biological uptake patterns in mollusks (bivalves Mytilus galloprovincialis and Anadara inequivalvis and gastropod Rapana venosa) highlighted Cd among key metals of concern, with elevated Bioconcentration Factor (BCF) and Biota–Sediment Accumulation Factor (BAF). Offshore waters generally exhibited lower pollution levels. However, isolated exceedances, such as Cr outliers recorded in 2022, suggest that deep-sea inputs from atmospheric or maritime sources may be both episodic in nature and underrecognized due to limited monitoring coverage. The combined use of water, sediment, and biota data emphasize the strength of multi-matrix approaches in marine pollution evaluation, revealing persistent nearshore pressures and less predictable offshore anomalies. These findings contribute to a more complete understanding of heavy metal distribution in the northwestern Black Sea and provide a scientific basis for improving long-term environmental monitoring and risk management strategies in the region. Full article

The kinetic parameters of No.0 fuel oil and Pinghu crude oil water-accommodated fractions (WAFs) during accumulation and elimination in Exopalaemon carinicauda were quantified using a semi-static two-compartment kinetic model. The accumulation phase data were analyzed via nonlinear regression to obtain kinetic parameters, yielding critical values including the uptake rate constant (k₁), elimination rate constant (k₂), bioconcentration factor (BCF), equilibrium body burden (C_Amax), and biological half-life (B_1/2). Modeling results demonstrated distinct kinetic parameters for the two oils. For No.0 fuel oil, the average values were k₁ = 5.21; k₂ = 0.1105; BCF = 48.98; C_Amax = 2.95 mg/kg; and B_1/2 = 6.40 days. For Pinghu crude oil, the averages were k₁ = 10.25; k₂ = 0.1044; BCF = 98.15; C_Amax = 8.48 mg/kg; and B_1/2 = 6.64 days. The uptake rate constant (k₁) and BCF generally decreased with increasing petroleum hydrocarbon exposure concentrations in ambient seawater, while the elimination rate constant (k₂) remained relatively constant across different concentrations. C_Amax increased proportionally with the petroleum hydrocarbon exposure concentration. Goodness-of-fit tests confirmed that the petroleum hydrocarbon concentrations in the experimental data were well described by the semi-static two-compartment model. Throughout the testing period, the concentration of No.0 fuel oil in Exopalaemon carinicauda remained lower than that of Pinghu crude oil. Full article

To investigate the responses and mechanisms of slash pine under low orthophosphate (Pi) stress and to identify Pi-efficient lines, we analyzed 12 indices related to biomass, root traits, and tissue Pi concentration across 13 slash pine lines subjected to varying Pi treatments. The composite assessment value of low-phosphorus tolerance (D) was calculated by evaluating these 12 response indicators through principal component analysis, in conjunction with the fuzzy membership function method. Nine low-phosphorus tolerance factors (LPTFs)—including above-ground fresh weight (0.69), below-ground fresh weight (0.52), total root length (0.56), root surface area (0.63), root volume (0.67), above-ground Pi concentration (0.78), below-ground Pi concentration (0.52), bioconcentration factor (0.77), and P utilization efficiency (−0.76)—showed significant correlations with D (p < 0.05). Utilizing these nine LPTFs, cluster analysis classified the 13 lines into the following three groups according to their low-phosphorus (P) tolerance: high-P-efficient, medium-P-efficient, and low-P-efficient lines. Under low Pi and Pi-deficiency treatments, line 27 was identified as a high-P-efficient line, while lines 1, 6, and 9 were classified as low-P-efficient lines. Notably, eight genes (SPX1, SPX3, SPX4, PHT1;1, PAP23, SQD1, SQD2, NPC4) and five genes (SPX1, SPX3, SPX4, PAP23, SQD1) were significantly up-regulated in the roots and leaves of both line 27 and line 9 under low-phosphorus stress, respectively. However, the high-P-efficient line 27 exhibited a stronger regulatory capacity with a higher expression of two genes (SPX4, SQD2) in the roots and nine genes (SPX1, SPX3, SPX4, PHT1;1, PAP10, PAP23, SQD1, SQD2, NPC4) in the leaves under low Pi stress. These findings reveal differential responses to low Pi stress among slash pine lines, with line 27 displaying superior low-P tolerance, enabling better adaptation to low Pi environments and the maintenance of normal growth, development, and physiological activities. Full article

The soil phytomonitoring and phytostabilization potential of Syringa vulgaris and Ficus carica was evaluated regarding 16 priority polycyclic aromatic hydrocarbons (PAHs) using a chemometric approach and the calculation of bioconcentration factors (BCFs) for each individual PAH in plants’ roots from each selected location in the Bor region. PAHs in roots and the corresponding soils were analyzed using the QuEChERS (Quick, Effective, Cheap, Easy, Rugged, Safe) method with some new modifications, gas chromatography/mass spectrometry, Pearson’s correlation study, hierarchical cluster analysis, and BCFs. Several central conclusions are as follows: Each plant species developed its own specific capability for PAH management, and root concentrations ranged from not detected (for several compounds) to 5592 μg/kg (for fluorene in S. vulgaris). In some cases, especially regarding benzo(a)pyrene and chrysene, both plants had a similar tactic—the total avoidance of assimilation (probably due to their high toxicity). Both plants retained significant quantities of different PAHs in their roots (many calculated BCFs were higher than 1 or were even extremely high), which recommends them for PAH phytostabilization (especially fluorene, benzo(b)fluoranthene, and benzo(k)fluoranthene). In soil monitoring, neither of the plants are helpful because their roots do not reflect the actual situation found in soil. Finally, the analysis of the corresponding soils provided useful monitoring information. Full article

Urban parks are an integral component of cities; however, they are susceptible to heavy metal contamination from anthropogenic sources. Here, we investigated the moss Pleurozium schreberi and tree leaves as bioindicators for monitoring heavy metal contamination in urban parks. We determined heavy metal concentrations in P. schreberi, leaf tissues of selected tree species, and soil samples collected from various locations within a designated urban parks. The order of heavy metal accumulation was Zn > Pb > Cr > Cu > Ni > Cd > Hg in soil and Zn > Cu > Pb > Cr > Ni > Cd > Hg in P. schreberi. The order was Zn > Cu > Cr > Ni > Pb > Cd > Hg in linden and sycamore leaves, while birch leaves displayed a similar order but with slightly more Ni than Cr. The heavy metal concentration in the tested soils correlated positively with finer textures (clay and silt) and negatively with sand. The highest metal accumulation index (MAI) was noted in birch and P. schreberi, corresponding to the highest total heavy metal accumulation. The bioconcentration factor (BAF) was also higher in P. schreberi, indicating a greater ability to accumulate heavy metals than tree leaves, except silver birch for Zn in one of the parks. Silver birch displayed the highest phytoremediation capacity among the analysed tree species, highlighting its potential as a suitable bioindicator in heavy metal-laden urban parks. Our findings revealed significant variation in heavy metal accumulation, highlighting the potential of these bioindicators to map contamination patterns. Full article

To investigate the remediation efficiency of different plant species on cadmium (Cd)-contaminated soil, this study conducted a pot experiment with two woody species (Populu adenopoda and Salix babylonica) and two herbaceous species (Artemisia argyi and Amaranthus hypochondriacus). Soils were collected from an abandoned coal mine and adjacent pristine natural areas within the dam-adjacent section of the Three Gorges Reservoir Area to establish three soil treatment groups: unpolluted soil (T1, 0.18 mg·kg⁻¹ Cd), a 1:1 mixture of contaminated and unpolluted soil (T2, 0.35 mg·kg⁻¹ Cd), and contaminated coal mine soil (T3, 0.54 mg·kg⁻¹ Cd). This study aimed to investigate the growth status of plants, Cd accumulation and translocation characteristics, and the relationship between them and soil environmental factors. Woody plants exhibited significant advantages in aboveground biomass accumulation. Under T3 treatment, the Cd extraction amount of S. babylonica (224.93 mg) increased by about 36 times compared to T1, and the extraction efficiency (6.42%) was significantly higher than other species. Among the herbaceous species, A. argyi showed the maximum Cd extraction amount (66.26 mg) and extraction efficiency (3.11%) during T2 treatment. While A. hypochondriacus exhibited a trend of increasing extraction amount but decreasing extraction efficiency with increasing concentration. With the exception of S. babylonica under T1 treatment (BCF = 0.78), the bioconcentration factor was greater than 1 in both woody (BCF = 1.39–6.42) and herbaceous species (BCF = 1.39–3.11). However, herbaceous plants demonstrated significantly higher translocation factors (TF = 1.58–3.43) compared to woody species (TF = 0.31–0.87). There was a significant negative correlation between aboveground phosphorus (P) content and root Cd (p < 0.05), while underground nitrogen (N) content was positively correlated to aboveground Cd content (p < 0.05). Soil total N and available P were significantly positively correlated with plant Cd absorption, whereas total potassium (K) showed a negative correlation. This study demonstrated that woody plants can achieve long-term remediation through biomass advantages, while herbaceous plants, with their high transfer efficiency, are suitable for short-term rotation. In the future, it is suggested to conduct a mixed planting model of woody and herbaceous plants to remediate Cd-contaminated soils in the tailing areas of reservoir areas. This would synergistically leverage the dual advantages of root retention and aboveground removal, enhancing remediation efficiency. Concurrent optimization of soil nutrient management would further improve the Cd remediation efficiency of plants. Full article