Search Results (321)

Thallium (Tl) contamination of soils in lead-zinc mining areas poses potential ecological risks, and the impact of microplastics on Tl accumulation by hyperaccumulator plants remains unclear. This study examined soils collected from the Daliangzi lead-zinc mining area to investigate the characteristics of Tl contamination. These soil samples were used in plant cultivation experiments. The thallium contents in both the soil and plant samples were determined using acid digestion followed by inductively coupled plasma mass spectrometry (ICP-MS). The contamination level, plant enrichment capacity, and ecological risk were then comprehensively evaluated through the Geo-accumulation index (I_geo), Bioconcentration factor (BCF), and potential ecological risk index. The results indicated that the I_geo of Tl in the soil was 2.413, corresponding to a moderately to heavily polluted level, which necessitates focused attention. Polyethylene exhibited markedly opposing effects on Pteris vittata and Solanum nigrum: it significantly promoted Tl accumulation in the former, while distinctly inhibiting it in the latter. Microplastics could modify the pH value of soil, as well as the contents of nitrogen (N) and phosphorus (P). Risk assessment indices indicated that Tl pollution in this region reaches a very high contamination level with moderate potential ecological risk. Polyethylene and polypropylene demonstrated a species-specific promoting effect on Tl adsorption by the two hyperaccumulator plants, with polyethylene significantly enhancing the Tl accumulation capacity of P. vittata and polypropylene distinctly promoting Tl adsorption in S. nigrum. Full article

High-altitude mine wastelands in Southwest China present formidable challenges for ecological rehabilitation due to extreme climatic stressors and multi-element contamination. Ecological restoration is closely related to soil environment. However, the mechanism by which parent material-induced heterogeneity governs spontaneous vegetation succession is still poorly understood. We established 36 plots (216 quadrats) to investigate the soil physical and chemical properties and vegetation restoration of propylite, porphyry and siltstone in the Xifanping Copper Mine, Sichuan Province. Furthermore, fifteen metal/metalloid elements (Au, Ag, Mo, W, Cu, Pb, Zn, Hg, As, U, Se, Cr, Sn, Ti, Total Fe₂O₃), soil pollution and vegetation structure were evaluated. The study area exhibited severe composite pollution (mean Nemerow integrated pollution index = 8.09), primarily driven by Au, Ag, Mo, W, and Cu. Vegetation surveys identified 34 vascular plant species from 12 families. Propylite-derived substrates supported significantly higher species richness, Shannon–Wiener diversity, and soil organic matter than porphyry and siltstone. Redundancy analysis (RDA) identified soil organic matter (SOM) and bulk density (BD) as dominant environmental filters, with SOM explaining 14.03% of community variance (p < 0.01). Two native pioneers, Potentilla supina and Cynoglossum wallichii, were identified as specialized uranium (U) accumulators with bioconcentration factors of 13.39 and 4.49, respectively. Lithological inheritance dictates early successional trajectories by influencing edaphic structure and nutrient bioavailability. The identified U-accumulating species provide a valuable genetic resource for implementing Assisted Natural Regeneration (ANR) and developing sustainable phytoremediation strategies in contaminated alpine ecosystems. Full article

Minimizing cadmium (Cd) contamination in rice grains is crucial for ensuring food security and promoting sustainable agriculture. Recent studies have investigated soil immobilization and foliar spraying for reduced cadmium accumulation in rice, yielding positive results. This study aimed to confirm the synergistic effects of the co-application of Ca-Mg soil immobilization and foliar spraying Si(OH)₄ on Cd uptake and transport in rice through field trials. The results indicated that Ca-Mg decreased the transfer of Cd from soil to root by 33.9% to 55.7%, Si(OH)₄ reduced the transfer of Cd from leaf to rachis by 43.8% to 69.7%, and the transfer of Cd from husk to brown rice was lowered by 33.4% to 61.2%. Compared with single application, co-application significantly decreased the bioconcentration factor (BCF)_{soil-brown rice} (p < 0.05), leading to brown rice Cd accumulation conforming to the National Food Safety Standard (<0.20 mg kg⁻¹),with an input–output ratio of 1.47–1.60. Furthermore, Ca-Mg + Si increased rice grain production. Comprehensive analyses using PLS-PM revealed that Ca-Mg and Si(OH)₄ directly or indirectly inhibited the translocation of Cd from stems to brown rice, with foliar-sprayed Si(OH)₄ significantly contributing to the reduction in Cd content in brown rice. Considering the economic cost and safety of production, Ca-Mg + Si(OH)₄ serves as a viable solution that promotes substantial rice growth and enhances yield while additionally inhibiting the accumulation and translocation of Cd in rice. Full article

The geochemistry of karstic paddy soils significantly influences Cd bioavailability and its accumulation by rice. However, there is limited research on Cd translocation and accumulation in rice, grown in paddy soil with elevated CaO and Zn levels. Addressing this, a field-based study in Hanyuan County, Sichuan Province, China, examined the Cd distribution and translocation patterns across the soil–root–straw–grain continuum, aiming to elucidate how elevated CaO and Zn levels regulate Cd accumulation in grains. The geochemical characterization of the soil revealed elevated concentrations of cadmium (Cd), calcium oxide (CaO), and zinc (Zn), with mean values of 2.12 ± 2.93 mg/kg, 5.77 ± 5.80 wt.%, and 359 ± 472 mg/kg, respectively. The sequential extraction results (by Tessier) demonstrated that the distribution of Cd followed the general order: residual > Fe-Mn oxide-bound ≈ exchangeable ≈ carbonate-bound > organic matter-bound. The exchangeable Cd content ranged from 0.063 to 0.93 mg/kg, accounting for up to 21.4% of the total Cd on average. The correlation analysis, Bioconcentration Factor (BCF), and Transfer Factor (TF) of Cd in different rice tissues, and structural equation modeling (SEM) revealed that elevated CaO and Zn levels in soil exhibit synergistic effects in inhibiting Cd accumulation in grains. Specifically, the CaO in soil reduces the Cd bioavailability by the formation of carbonate-bound specie (CdF2), thereby inhibiting Cd uptake by roots. In rice tissues, Zn could limit Cd translocation, particularly from roots to straws. Consequently, the regional rice Cd exceedance rate (25.8%) was significantly lower than that reported for other similar karst soils in China (over 50%). Full article

A study on the sources, bioconcentration, and translocation of heavy metals in Haloxylon ammodendron in the Eastern Junggar Coalfield, Xinjiang, China, was conducted and evaluated. The quantities of Pb, Cd, and Cr were 1.2, 22.5, and 1.9 times higher than the baseline values of Xinjiang soils, respectively. The mean concentrations of these heavy metals in the rhizosphere soil of Haloxylon ammodendron were 48.81, 17.74, 93.25, 3.32, 29.05, and 26.95 mg/kg. The exceedance rates for Cd, Cr, and Pb in bare soil were 100%, 99.03%, and 75.73%, respectively, indicating significant accumulation of heavy metals, with Cd demonstrating the highest enrichment degree. Most sampling sites showed moderate pollution according to the Pollution Load Index (PLI). Meanwhile, the Pollution Index (PN) indicated elevated pollution levels at all the sampling sites, with Cr identified as the first contaminant. The absolute principal component score–multiple linear regression (APCS-MLR) model revealed three principal sources of heavy metal pollutants in soil: 44.2% from natural processes and mining activities, 22.7% from industrial coal combustion and sewage, and 33.1% of undetermined origins. The bioconcentration factors (BCFs) and translocation factors (TFs) revealed Haloxylon ammodendron to have clear accumulation and translocation abilities with respect to these heavy metals. The fuzzy membership function showed that the overall assessment score for Haloxylon ammodendron was 9.1325, indicating the substantial remediation potential of Haloxylon ammodendron for heavy metal pollutants, especially for Cd. Furthermore, Haloxylon ammodendron demonstrated substantial Pb and Cr accumulation and remediation ability. Haloxylon ammodendron exhibited remarkable heavy metal accumulation and translocation abilities, making it a suitable tool for phytoremediation in the study area. The findings of this study will prove useful in promoting and implementing sustainable mining practices and safeguarding regional ecological security and may contribute to advancing local ecological conservation and social economic development. Full article

Nitric oxide (NO) is recognized as a key signaling molecule involved in plant tolerance to abiotic stress. Yet, its role in regulating cadmium (Cd) detoxification and ion homeostasis remains insufficiently understood across different lettuce genotypes. This study aimed to elucidate the NO-mediated mechanisms underlying Cd stress mitigation by focusing on oxidative regulation, ion balance, and Cd accumulation dynamics in lettuce. Three lettuce varieties (Lactuca sativa L.), namely curly (var. crispa), romaine (var. longifolia), and iceberg (var. capitata), were exposed to 100 and 500 µM Cd, with or without 200 µM sodium nitroprusside (SNP), under controlled greenhouse conditions in a modified Hoagland solution. Growth traits, antioxidant enzyme activities [catalase (CAT) and ascorbate peroxidase (APX)], oxidative stress markers [hydrogen peroxide (H₂O₂), malondialdehyde (MDA), membrane permeability (MP), and proline], ionic homeostasis [potassium (K), calcium (Ca), iron (Fe), zinc (Zn), copper (Cu), and manganese (Mn)], and Cd accumulation indices [bioconcentration factor (BCF), translocation factor (TF), total accumulation rate (TAR), and net accumulation via roots (NetAcc)] were evaluated. Cd exposure significantly reduced biomass production, photosynthetic pigment contents, and the accumulation of essential mineral nutrients, while markedly increasing oxidative stress indicators. Antioxidant responses varied among varieties, with Cd generally stimulating CAT activity but suppressing APX, indicating redox imbalance. SNP application partially restored antioxidant enzyme activities, reduced membrane damage, and alleviated oxidative stress in a genotype-dependent manner. Cd accumulation indices revealed substantial Cd uptake and translocation, particularly in curly and iceberg lettuce. SNP significantly reduced BCF, TF, TAR, and NetAcc values, suggesting NO-mediated restriction of Cd mobility, possibly through enhanced root sequestration and detoxification processes. Moreover, SNP improved K⁺, Ca²⁺, Fe²⁺, and Mn²⁺ homeostasis, highlighting its role in maintaining selective ion transport under Cd stress. Among the tested varieties, curly lettuce exhibited the highest NO-induced tolerance, followed by iceberg and romaine lettuce. Overall, the findings demonstrate that NO acts as an effective regulator of redox balance, ion homeostasis, and Cd detoxification, thereby enhancing physiological resilience and reducing Cd accumulation in lettuce exposed to Cd stress. From a sustainability perspective, these findings highlight the potential of NO application as an effective strategy to reduce Cd accumulation in leafy vegetables, thereby contributing to safer food production and more sustainable crop management under heavy metal-contaminated conditions. Full article

Heavy metal pollution in mining wastelands poses a serious threat to soil quality and ecosystem sustainability, particularly in cold-climate regions where phytoremediation efficiency remains poorly understood. The present study aims to determine the risk of heavy metals in soils and the phytoremediation potential of native dominant spontaneous plants in lead–zinc mining wasteland and located in a cold region characterized by harsh winters and heavy snowfall. Soil samples (n = 60) and plant tissues (n = 84) were collected across the study area, and the concentrations of Cd, Pb, Zn, and Cu in rhizosphere soils and plant tissues were determined using atomic absorption spectrophotometry. Bioconcentration and translocation factors were calculated to evaluate plant metal enrichment and transport capacities. The results revealed that the concentrations of Cd, Pb, Zn, and Cu were at a relatively high potential ecological hazard level in the tailing ponds and surrounding areas. Field surveys showed that indigenous dominant spontaneous plants were better adapted to the harsh climatic conditions and poor soil matters than non-native plants, making them more economical and reliable candidates for phytoremediation. The study unexpectedly identified Commelina communis as a Cu phytostabilization candidate and found several metal-enriching plant species (n = 6), including Scirpus, Typha, Carex, Artemisia, Commelina, and Polygonum. The results can serve as a basic plant resource database for government institutions related to natural, ecological, and environmental sustainable management, offering new insights into self-sustaining phytoremediation strategies and sustainable ecological restoration in cold-region mining areas. Full article

Leafy green vegetables provide important nutrients for human growth; however, human health is highly compromised through consumption of vegetables contaminated by heavy metals. Therefore, the study aimed to investigate the bioaccumulation of heavy metals in five different leafy green vegetables and soils and determine the human health risks that may arise from consuming those vegetables from Tonga town in Mpumalanga province, South Africa. Soils and five edible leafy vegetables (i.e., lettuce, cabbage, rape, pumpkin leaves, and spinach) were assessed for bio-concentration factor, daily intake of metals, health risk, and target hazard quotient across the study sites. The Si, K, Na, Ca, Mg, Al, and Fe concentrations were high in the soils. In general, vegetables exhibited elevated Ca, Fe, Si, Al, and Sr levels, although spinach had high Na concentrations. The bioconcentration factor showed the following trends: Mg > B > Si > V for trace metals and Cr > Co > Mn > Ni > B for heavy metals in lettuce, spinach, and pumpkin leaves. The human risk index for all vegetables showed that all metals were not likely to induce any health hazards to humans, and the target hazard quotient for B, Si, V, Al, Cr, Mn, Fe, Ni, Zn, and Pb showed potential for substantial health risk hazard. The findings of this study generally reveal that the concentrations of the analysed metals exceeded the permissible limits established by the World Health Organisation and the Food and Agricultural Organisation. Given the high levels of metals detected in the soil and vegetables within the study area, it is important to investigate the potential implications for human health and mitigate both acute and chronic health challenges associated with heavy metal exposure. Furthermore, this study will guide policymakers in developing improved regulations and safety standards for agricultural practices and environmental protection, particularly for vulnerable peri-urban and rural communities. Full article

To investigate the regulatory mechanisms of arbuscular mycorrhizal fungi (AMF) on the growth, cadmium (Cd) uptake and translocation of plants with distinct mycorrhizal dependency (MD), a pot experiment was conducted using Paspalum notatum (high MD) and Lolium perenne (low MD) under two Cd gradients (5 mg·kg⁻¹, 50 mg·kg⁻¹) with AMF-inoculated/non-inoculated treatments, with 0 mg·kg⁻¹ set as the control group. AMF significantly enhanced the dry weight and colonization rate of both plant species, and the MD of Paspalum notatum remained consistently higher. The growth-promoting effect of AMF (quantified by MD) exceeded the toxicity induced by Cd stress, thereby mitigating growth inhibition by promoting hyphal growth in the rhizosphere. AMF improved the root bioconcentration factor (BCF) and total Cd extraction capacity of the plants, which was correlated with the plants’ inherent Cd absorption capacity but not with MD. AMF exerted species-specific regulatory effects on the translocation factor (TF): the TF of Paspalum notatum increased after inoculation, while that of Lolium perenne decreased. Full article

Phytoremediation is an eco-friendly and in situ solution for remediating heavy metal-contaminated soils, yet practical application requires timely and accurate effectiveness evaluation. However, conventional chemical analysis of plant parts and soils is labor-intensive, time-consuming and limited for large-scale monitoring. This study proposed a rapid sensing framework integrating laser-induced breakdown spectroscopy (LIBS) with deep transfer learning and spectral indices to assess phytoremediation effectiveness of Sedum alfredii (a Cd/Zn co-hyperaccumulator). LIBS spectra were collected from plant tissues and diverse soil matrices. To overcome strong matrix effects, fine-tuned convolutional neural networks were developed for simultaneous multi-matrix quantification, achieving high-accuracy prediction for Cd and Zn (R²_test > 0.99). These predicted concentrations enabled calculating conventional phytoremediation indicators like bioconcentration factor (BCF), translocation factor (TF), plant effective number (PEN), and removal efficiency (RE), yielding recovery rates near 100% for TF and PEN. Additionally, novel spectral indices (SIs)—directly derived from characteristic wavelength combinations—were constructed to bypass intermediate quantification. SIs significantly improved the direct evaluation of Zn removal and translocation. Finally, a decision-level fusion strategy combining concentration predictions and SIs enhanced Cd removal assessment accuracy. This study validates LIBS combined with intelligent algorithms as a rapid sensor tool for monitoring phytoremediation performance, facilitating sustainable environmental management. Full article

The present study examined the safety of 86 veterinary antiparasitic drugs in mammals based on their mobility in the soil–water compartment, bioconcentration factor in fish, and blood–brain barrier permeability. An in silico analysis was performed based on biomembrane permeability descriptors, using novel multiple linear regression, boosted tree, and artificial neural network models. Additionally, intestinal absorption in humans was predicted quantitatively using pkCSM software and qualitatively using SwissADME. It was established that the majority of studied drugs are at least slightly mobile in soil, are unlikely to bioaccumulate in fish, and may be absorbed from the human gastro-intestinal tract; in addition, some of them have high potential to enter the mammalian brain. Full article

Heavy metals are among the most hazardous pollutants to human health and can be particularly harmful when inhaled or ingested. Therefore, the concentrations of heavy metals in fruits and vegetables grown in regions with high levels of heavy metal pollution should be carefully examined. This study investigated the variation in aluminum (Al), nickel (Ni), and zinc (Zn) concentrations by species and organ in tomatoes, peppers, eggplants, cucumbers, and corn grown near the industrial zone in Düzce, a heavily polluted city in Europe. We determined bioconcentration factors (BCFs) and translocation factors (TFs) in plant organs and assessed the health risk through the Target Hazard Quotient (THQ) and Hazard Index (HI). The results show that Al pollution in the region significantly exceeded the World Health Organization (WHO) and European Union (EU) limit values, and accumulated in all plant organs, including fruits. Furthermore, high levels of metals were translocated from the soil into the organs of peppers and tomatoes. The HI indicated a potential non-carcinogenic health risk (HI > 1) from the consumption of tomatoes, cucumbers, and peppers, primarily driven by Ni. Based on these results, it is recommended that local authorities address Al pollution in the region, avoiding the cultivation of tomatoes and peppers and instead cultivating corn and eggplant. We also observed that Zn levels were very high in the aerial parts of the plants, reaching up to 90% compared to Ni and Al. This study underscores the need to reduce Zn absorption rates, as dietary intake can pose a significant threat to human health. 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

Modern pesticide risk assessment relies on data on bioaccumulation and acute aquatic toxicity, yet generating such data is labour-intensive and animal-demanding. This study evaluated whether phospholipid affinity of pesticides, quantified by the chromatographic hydrophobicity index CHI_IAM obtained from high-throughput gradient biomimetic chromatography, can serve as a surrogate descriptor of these endpoints. Nineteen pesticides representing different chemical and functional classes were analyzed on IAM.PC.DD2 columns, and CHI_IAM values were determined. Bioconcentration factors (BCF) in fish and acute toxicity data (96 h LC₅₀ for fish, 48 h EC₅₀ for Daphnia magna) were retrieved from the Pesticide Properties DataBase. CHI_IAM ranged from −12.1 to 54.8 and correlated strongly with log₁₀BCF (r = 0.84) and log₁₀LC₅₀ in fish (r = −0.84), and moderately with log₁₀EC₅₀ for Daphnia (r = 0.76). Highly lipophilic pesticides with high CHI_IAM showed elevated BCF and low LC₅₀/EC₅₀ values, whereas polar compounds with low CHI_IAM exhibited negligible bioconcentration and low acute toxicity. Deviations from these trends, for compounds with specific modes of action, highlighted the contribution of mechanisms beyond membrane toxicity. Overall, CHI_IAM measured under high-throughput conditions retains prognostic value for ecotoxicological assessment and may serve as a rapid experimental descriptor to support preliminary screening. Full article

Agricultural soils surrounding mining areas are often polluted with heavy metals (HMs) due to long-term mining activities and high geological background values. In this study, we investigated the distribution and transport of Cu, Cr, Zn, Cd, Pb, and As in a soil–rice system near a century-old mining site, evaluated their toxic effects on rice (Oryza sativa L.) throughout the growth period, and assessed the associated health risks using the Nemerow index and potential ecological risk index. The results showed that HM contents in rice grown in contaminated soils were significantly higher than in the control. HMs mainly accumulated in roots, with the lowest contents in grains. Cd exhibited the highest enrichment capacity, with bioconcentration factors of 0.79, 1.04, and 1.95 at the tillering, heading, and maturity stages, respectively, and its accumulation increased with rice growth. Transport from stems to leaves was relatively strong. HM exposure significantly inhibited rice growth, reducing plant height, biomass, tiller number, and panicle emergence. In addition, oxidative stress indicators and antioxidant enzyme activities, as well as root amino acid exudation, were markedly altered under HM stress. According to soil–rice HM contents, the pollution level of agricultural soils reached a high class, with As, Pb, Cd, and Zn as the main contributors. The potential ecological risk reached a moderate level, with Cd identified as the dominant factor. Notably, the health risks to children were substantially higher than those to adults, and Monte Carlo simulation indicated a 100% probability of non-carcinogenic and carcinogenic risks for adults and children. The above results highlighting the urgent need for risk management in mining-affected regions. Full article