Search Results (33)

Soil contamination with heavy metals (HMs) poses a significant environmental threat. Phytoremediation, a sustainable and eco-friendly emerging bioremediation approach, utilizes plants to remove, immobilize, or stabilize soil contaminants. This study examines the interactive effects of sulfur (S), ethylenediaminetetraacetic acid (EDTA), and olive mill wastewater (OMW) on HM uptake and the growth of maize (Zea mays L.) and mustard (Brassica juncea). Mustard exhibited superior dry matter (DM) yield (2.4 g/pot with 5% OMW), nutrient uptake, and tolerance to metal toxicity. The translocation factor (TF) and bioaccumulation factor (BF) for maize and mustard plants vary significantly with different treatments. For maize, the S 2T/ha treatment achieved the highest TF and BF for cadmium (Cd), while 5% OMW led to maximum chromium (Cr) and manganese (Mn) uptake. In mustard, 5% OMW treatment resulted in the greatest bioconcentration factor (BCF) for cadmium (Cd), lead (Pb), and zinc (Zn), whereas sulfur application yielded the highest TF for Cd. The 5% OMW treatment overall enhanced HM uptake most significantly. Lower sulfur application rate (1 ton/hectare) increased the availability Cd and Pb, boosting plant growth and nutrient uptake. For instance, 1 ton/hectare of sulfur elevated Cd availability to 24.102 mg·kg⁻¹ in maize and 58.705 mg·kg⁻¹ in mustard. EDTA treatments further improved metal bioavailability, increasing Cd levels in maize (10.09 mg·kg⁻¹) and mustard (7.78 mg·kg⁻¹). Mustard’s superior tolerance and nutrient efficiency identify it as a promising candidate for phytoremediation of HM-contaminated soils in arid regions. Innovative treatments with sulfur, EDTA, and olive mill wastewater significantly enhance soil decontamination and plant growth. Full article

Microplastic (MP) contamination in soil is an emerging environmental concern, influencing the mobility and bioavailability of heavy metals (HMs). This study investigates how different MP types (PP, PS, PVC, HDPE, LDPE, PES, and PET-Glitter) affect HM behavior in soil, focusing on sorption/desorption, and the extraction efficiency of Pb, Cu, Co, Ni, Cr, and Cd. Soil samples incubated with MPs showed significant pH increases, particularly with PES and HDPE at 0.8 and 0.6 pH units, respectively. The extraction experiments using 0.05 M EDTA and 0.01 M CaCl₂ revealed that MPs altered metal bioavailability—with HDPE reducing Pb mobility by 15%—and increased Cd and Co mobility by 10–20%. The batch sorption tests confirmed higher Pb adsorption onto HDPE but decreased Cd and Co sorption compared to control soils without MP. These findings demonstrate that MPs act as additional sorption sites, modifying metal speciation and availability, which has critical implications for soil health, agricultural sustainability, and remediation strategies. However, results may vary based on soil type, MP aging, and environmental conditions, indicating the need for further long-term field studies. This research provides valuable insights into the complex interactions between MPs, heavy metals, and soil systems, contributing to a better understanding of pollution dynamics and risk assessment in contaminated environments. Full article

Bulgarian wines are renowned worldwide and serve as a symbol of the country. However, ensuring wine authenticity and establishing reliable methods for its assessment are critical challenges in wine quality control. This study investigates the migration of chemical elements within the soil/grape/wine system and utilizes the findings to develop a method for identifying specific elements capable of distinguishing the geographical origin of wine. Additionally, it explores the potential to determine its botanical origin. Thirty monovarietal Bulgarian wines, specifically produced for this study with precisely known geographical and botanical origins, were analyzed for 20 chemical elements. These included macroelements such as Al, B, Ba, Ca, Cu, Fe, K, Mg, Mn, Na, P, Sr, and Zn, as well as microelements like As, Cd, Co, Cr, Li, Ni, and Pb. The study encompassed white wines from Chardonnay, Muscat Ottonel, Sauvignon Blanc, Tamyanka, and Viognier varieties, as well as red wines from Egiodola, Broad-Leaved Melnik, Cabernet, Cabernet Franc, Cabernet Sauvignon, Marselan, Melnik, Merlot, Pinot Noir, and Syrah. The chemical composition was determined in soil extracts (using acetate and EDTA extract to represent the bioavailable fraction), vine leaves, primary musts, and raw wines before clarification and stabilization. Statistically significant correlation coefficients were calculated for the soil/leaves, soil/must, and must/wine systems, enabling an analysis of the migration of chemical elements from soil to wine and the concentration changes throughout the process. The results identified elemental descriptors capable of indicating the geographical origin of wine. Full article

Heavy metal pollution has become increasingly severe, with distinctive physiological characteristics of rice leading to significant accumulation of arsenic (As) and cadmium (Cd) in grains, posing serious health risks. Biological soil crusts (BSC) are common in paddy soils and exhibit a strong capacity to bind trace heavy metals. This study investigated the effects of exogenous iron (Fe)/manganese (Mn) and urea on the effectiveness of BSC (20 mg L⁻¹) in removing As (2 mg L⁻¹) and Cd (100 μg L⁻¹) and analyzed the heavy metal distribution. Fe/Mn addition increased As adsorption by BSC from 51.2% to 83.0% but reduced Cd adsorption from 73.2% to 50.3%, whereas urea inhibited As uptake but enhanced Cd capture. Under co-contamination, the As removal ability of the BSC remained unchanged, but Cd removal improved. As was primarily present in the non-EDTA exchangeable fraction (79.0%), which increased to 96.4% and 85.8% in the presence of Fe/Mn, and urea, respectively. Cd was mainly in the sorbed fraction (51.6%), which increased to 61.0% with urea. These results confirm that BSC exhibits a strong ability to adsorb As and Cd under irrigated water with combined As and Cd contamination, iron/manganese and urea can also enhance this ability. The application of exogenous Fe/Mn providing the raw material for the mineralization process and the presence of urea enhancing the biological activity of the colonies. This study provides an eco-friendly strategy for remediating As and Cd in paddy fields. Full article

In order to effectively decrease cadmium (Cd) in rice grains in contaminated paddy soil and maintain the safe production of rice, identifying excessive Cd in rice caused by rice varieties or soil Cd is critical, but it is currently lacking. In the present study, the soil ethylenediaminetetraacetic acid (EDTA)-extractable Cd (EDTA-Cd) and the bioaccumulation factors of rice based on EDTA-Cd (BCF_EDTA-Cd) were used to develop an approach to identify excessive Cd in rice caused by rice varieties or soil Cd. Based on an empirical soil–plant transfer model and species sensitivity distribution (SSD), BCF_EDTA-Cd and EDTA-Cd were divided into five grades. The results showed that the five grades of the EDTA-Cd (minimum value less than 0.11 mg/kg and maximum value greater than 2.93 mg/kg) and BCF_EDTA-Cd (minimum value less than 0.09 and maximum value greater than 1.40) were classified in the normal soil pH range. Further, the conversion equation between EDTA-Cd and diethylene triamine pentaacetic acid (DTPA)-Cd was obtained through linear regression analysis using 67 sets of soil data from the literature. In addition, the four selected rounding thresholds for the percentage of EDTA-Cd to total soil Cd (EDTA-Cd) (%) were 52.5, 67.5, 82.5, and 97.5%. A selected soil EDTA-Cd (%) (about 75%) can be used to identify the status of soil bioavailability, especially in soil with high background Cd. Finally, a set of 1084 pairs of rice and soil data for Cd-contaminated soils was used to investigate the respective contributions of rice varieties and soil Cd when Cd in rice exceeds the limit (0.2 mg/kg). Based on field experiment data, a systematic identification approach for the causes of rice Cd exceeding the limit, soil Cd or rice variety, was established and applied. In conclusion, under Cd exposure conditions, the importance of the causes of Cd in soil and rice varieties can be identified, and their contributions can be distinguished, thus helping to identify the causes of Cd contamination in rice. Full article

Foliar zinc (Zn) application can affect the accumulation and bioaccessibility of cadmium (Cd) and Zn in crops. However, the mechanisms by which foliar Zn application influences Cd and Zn bioaccessibility remain elusive. This study examined the effects of spraying ZnSO₄ and ZnNa₂EDTA on bioaccessibility and chemical forms of Cd and Zn in pakchoi (Brassica chinensis L.) shoots and evaluated human health risks via pakchoi consumption. Spraying ZnSO₄ reduced the concentrations of ethanol-extractable (F_ethanol) and deionized water-extractable (F_d-H2O) Cd, as well as the corresponding bioaccessible Cd concentrations (20.3–66.4%) and attendant health risks of Cd, whereas spraying high-dose ZnNa₂EDTA significantly increased the concentrations of both Cd forms and bioaccessible Cd. Spraying ZnSO₄ and high-dose ZnNa₂EDTA significantly increased the concentrations of Zn in F_ethanol and F_d-H2O and the corresponding bioaccessible Zn concentrations (0.8–8.3-fold). F_ethanol and F_d-H2O were the primary sources of bioaccessible Cd and Zn, contributing more than 59% of the bioaccessible Cd and Zn. These results indicate that foliar Zn application can affect Cd and Zn bioaccessibility in pakchoi mainly by modulating Cd and Zn in F_ethanol and F_d-H2O. These findings provide scientific support for the development of more efficient measures to produce safe and high-quality leafy vegetables from Cd-polluted soils. Full article

Phytoremediation is considered an effective strategy for remediation of heavy-metal-contaminated soil in mining areas. However, single-species plants cannot reach the highest potential for uptake of heavy metals due to inhibition of their growth by high concentrations of heavy metals in the soil. Therefore, this study has explored the effects of illite application and two plant species’ co-cropping on soil quality, plant growth, and heavy metal transformation in a soil–plant system. The results reveal that the addition of 1% (mass fraction) of illite significantly enhances soil pH. The co-cropping of Ilex cornuta and Epipremnum aureum is beneficial for improving the organic matter content of the soil. The contents of EDTA-extractable Pb, Zn, and Cu were significantly reduced by 29.8–32.5%, 1.85–5.72%, and 30.0–32.9%, respectively, compared to the control. The co-cropping of Ilex cornuta and Epipremnum aureum promoted enrichment effects of Epipremnum aureum on Pb and Ilex cornuta on Cd (p < 0.05). The co-cropping pattern lowered the biomass of Ilex cornuta and Epipremnum aureum; however, co-cropping of Ilex cornuta and Epipremnum aureum promoted the elimination of Pb, Zn, Cu, and Cd from the soil at 13.0–75.8%, 11.1–38.2%, 8.39–88.4%, and 27.8–72.5%, respectively. It is concluded that illite application combined with co-cropping of Ilex cornuta and Epipremnum aureum is highly effective for the elimination of Pb, Zn, Cu, and Cd from contaminated soil. This study provides a theoretical basis and pathway for the restoration of heavy-metal-contaminated soil in mining with the application of bentonite combined with phytoremediation. Full article

Despite notable achievements in the development and application of the remediation of metal-contaminated soils, the search for and study of promising immobilizing agents continues. This article presents a new approach to using brown coal and activated carbon and their application for metal stabilization. An experiment was conducted to test Medicago falcata L. on soils from industrial areas contaminated with varying levels of lead (Pb), cadmium (Cd), chromium (Cr), zinc (Zn), copper (Cu), and nickel (Ni) with the addition of carbons. This plant is a stress-tolerant leguminous species. In this study, the total content of metals in soil and the available forms to plants (single extractions with 0.02 M ethylenediaminetetraacetic acid, EDTA) were determined, along with metal contents in the plant. The use of carbons lowered the phytoavailable forms of metals for plants and thus, resulted in a reduction in the phytotoxicity of the soils. The contents of the tested metals in the roots and shoots were lower than in the combinations of soils with no carbon added. The activated carbon had a stronger effect on limiting the availability of metals than brown coal in relation to plants growing on soils without added carbon; the percentage of reduction for the shoots was Cr (18.2%) > Zn (11.5%) > Ni (10.7%) > Cu (10.3%) > Cd (8.9%) > Pb (2.4%) and Cu (13.3%) > Cr (12.5%) > Zn (10.5%) > Pb (9.0%) > Ni (5.7%) > Cd (4.6%) for roots. Metals reduced the growth of Medicago falcata L. roots from 44 to 21%, while the growth of shoots was reduced from 25 to 2%. Adding carbons to soils in all combinations resulted in a decrease in the following pollution indices: pollution index (PI), pollution load index (PLI), and non-carcinogenic (HQ) and carcinogenic risk factors (ILCR). Full article

High concentrations of toxic cadmium (Cd) in soils are problematic as the element accumulates in food crops such as rice and cacao. A mitigation strategy to minimise Cd accumulation is to enhance the competitive uptake of plant-essential metals. Theobroma cacao seedlings were grown hydroponically with added Cd. Eight different treatments were used, which included/excluded hydroponic or foliar zinc (Zn) and/or iron (Fe) for the final growth period. Analyses of Cd concentrations and natural stable isotope compositions by multiple collector ICP-MS were conducted. Cadmium uptake and translocation decreased when Fe was removed from the hydroponic solutions, while the application of foliar Zn-EDTA may enhance Cd translocation. No significant differences in isotope fractionation during uptake were found between treatments. Data from all treatments fit a single Cd isotope fractionation model associated with sequestration (seq) of isotopically light Cd in roots and unidirectional mobilisation (mob) of isotopically heavier Cd to the leaves (ε¹¹⁴Cd_seq-mob = −0.13‰). This result is in excellent agreement with data from an investigation of 19 genetically diverse cacao clones. The different Cd dynamics exhibited by the clones and seen in response to different Fe availability may be linked to similar physiological processes, such as the regulation of specific transporter proteins. Full article

Testing the feasibility of soil phytoremediation requires the development of models applicable on a large scale. Phytoremediation mechanisms include advanced rhizosphere biodegradation, phytoaccumulation, phytodegradation, and phytostabilization. The aim of this study was to evaluate the phytoremediation potential of the Sinapis alba. Identification of the factors influencing the extraction process of metals from contaminated soils in a laboratory system suitable for evaluating the phytoavailability of these metals in three solutions (M1-CaCl₂, M2-DTPA, and M3-EDTA) included the following: distribution of metals in solution (Kd), soil properties and mobile fractions (SOC, CEC, pH), response surface methodology (RSM), and principal component analysis (PCA). The evaluation of the phytoremediation potential of the Sinapis alba plant was assessed using bioaccumulation coefficients (BACs). The accumulation of heavy metals in plants corresponds to the concentrations and soluble fractions of metals in the soil. Understanding the extractable metal fractions and the availability of metals in the soil is important for soil management. Extractable soluble fractions may be more advantageous in total metal content as a predictor of bioconcentrations of metals in plants. In this study, the amount of metal available in the most suitable extractors was used to predict the absorption of metals in the Sinapis alba plant. Multiple regression prediction models have been developed for estimating the amounts of As and Cd in plant organs. The performance of the predictive models generated based on the experimental data was evaluated by the adjusted coefficient of determination (aR2), model efficiency (RMSE), Durbin–Watson (DW) test, and Shapiro–Wilk (SW) test. The accumulation of the analyzed metals followed the pattern Root > Pods > Leaves > Seeds, stems > Flowers for As and Leaves > Root > Stem > Pods > Seeds > Flowers for Cd in soil contaminated with different metal concentrations. The obtained results showed a phytoremediation potential of the Sinapis alba plant. Full article

This study investigated the removal of cadmium (Cd) and lead (Pb) from the soil through phytoremediation using ryegrass combined with chelating agents. Soil leaching experiments were employed to determine the extraction efficiencies of chelating agents, including ethylenediaminetetraacetic acid (EDTA), citric acid (CA), sodium glutamate tetra acetate (GLDA), oxalic acid (OA), and diethylenetriaminepentaacetic acid (DTPA) on Cd and Pb. Soil pot experiments were conducted to determine the effects of five different chelating agents—GLDA, EDTA, DTPA, CA, and OA—on the growth of ryegrass and the enrichment of Cd and Pb. The main findings were as follows: (1) the extraction efficiencies for Cd and Pb in soil were found to be GLDA > EDTA > DTPA > CA > OA and EDTA > DTPA > GLDA > CA > OA, respectively. (2) The aminopolycarboxylic acid class of chelating agents significantly reduced Cd and Pb contents in the weak acid extractable and reducible states in the studied soil, yet were less effective in the extraction of their residue state. Using chelating agents increased the proportion of residual heavy metals while reducing those in the weak acid extractable and reducible states in the soil, thereby mitigating the harmful effects of these heavy metals on the soil ecology. Full article

The aim of the current study was to assess the cadmium (Cd) phytoremediation potential of Helianthus annuus L. that was exposed to 50, 100, and 150 mg/kg of cadmium for 15, 30, and 60 days with application of EDTA (Ethylenediaminetetraacetic acid) in the soil and IAA (indole acetic acid) as a foliar spray. The results indicated that the concentration, duration of exposure, and amount of Cd affect the phytoremediation potential. The maximum Cd was observed at 60 days (32.05, 16.86, and 10.63%) of Cd application, compared to 15 (2.04, 0.60, and 1.17%) or 30 days (8.41, 3.93, and 4.20%, respectively), in a dose-dependent manner. The application of EDTA in the soil and foliar IAA enhanced the Cd accumulation in the plants at 15, 30, and 60 days of exposure, with maximum accumulation at 60 days. Exposed plants with foliar IAA application showed 64.82%, 33.77%, and 25.84% absorption at 50, 100, and 150 mg/kg, respectively. Apart from higher absorption, the cadmium translocation to the edible part of the plants ceased, i.e., the seeds had 0% accumulation. The interesting fact was recorded that efficient phytoremediation was recorded at 15 days of exposure, whereas maximum phytoremediation was recorded at 60 days of exposure. To minimize the stress, the host also produced stress-related metabolites (i.e., flavonoids, phenolics, proline, and sugar) and antioxidants (i.e., catalases and ascorbate peroxidases). From the current evidence, it could be assumed that the use of EDTA and IAA, along with hyperaccumulating plants, could be a possible green method to remediate Cd-contaminated soil efficiently in a short period of time. Full article

Soil remediation is an important practice in the restoration of heavy metal-contaminated soils and reduce the heavy metal exposure of the local population. Here, we investigated the effect of an ex-situ soil washing technique, based on ethylenediaminetetraacetic acid (EDTA) as a chelating agent, on a contaminated Cambisol. Lead, Cd and Zn were investigated in different soil fractions, drainage water and four vegetables from August 2019 to March 2021. Three treatments consisting of (C) contaminated soil, (W) washed soil and (WA) washed soil amended with vermicompost and biochar were investigated in an outdoor raised bed set up. Our results showed that the total and bioavailable metal fractions were significantly reduced but failed to meet Austrian national guideline values. Initial concentrations in the soil leachate increased significantly, especially for Cd. Vegetables grown on the remediated soil took up significantly lower amounts of all heavy metals and were further reduced by the organic amendment, attaining acceptable values within EU guideline values for food safety. Only spinach exceeded the thresholds in all soil treatments. The increase in soil pH and nutrient availability led to significantly higher vegetable yields. Full article

In order to investigate the effects of Cl⁻ and SO₄²⁻ based fertilizers on the accumulation of cadmium (Cd) in rice plants, a long-term experiment, which has been conducted since 1975, and a short-term pot experiment were designed. The results of the long-term experiment showed that the highest total grain Cd was found in the treatment of fertilizers with rich Cl⁻, which was 72.7% higher compared to conventional fertilization (CF). However, there was no significant difference between the CF and fertilization with rich SO₄²⁻ treatments. This phenomenon can be explained by the concentrations of the EDTA extractable Cd being significantly increased by 60% under Cl⁻ treatment, while SO₄²⁻ treatment showed no significant effect. In the short-term trial, compared to CF, Cd concentrations in the roots increased by 1.07 and 0.93 times in the Cl⁻ and SO₄²⁻ treated soils, respectively, under Cd1.2 exposure. Meanwhile, Cd concentrations in the shoots enhanced by 96% in Cl⁻ treated soil but decreased by 34.6% in SO₄²⁻ treated soil. It was therefore concluded that fertilizer-borne Cl⁻ significantly increased the Cd concentration in rice grains in the long-term experiment, but fertilizer-borne SO₄²⁻ had no significant effect on the Cd concentration in rice grains. However, in the pot experiment, SO₄²⁻ based fertilizers decreased Cd transport to the shoots of a rice plant grown in a Cd contaminated soil. These findings will improve the rational fertilization of Cd contaminated soils and the production of safer rice. Full article

Heavy metal-polluted soil represents an important stress condition for plants. Several studies demonstrated that growth inhibition under metal stress and metal-induced damages, including genotoxicity, is particularly pronounced at the early stages of seedling growth. Moreover, it is reported that heavy metals enter the cytoplasm to exert their detrimental effect, including DNA damage. In this work, we estimated (i) metal-induced genotoxicity by ISSR molecular markers and (ii) the distribution of the metal fractions between symplast and apoplast by EDTA washing, in three cultivars of Cynara cardunculus var. altilis (L.) DC (Sardo, Siciliano, and Spagnolo), grown in hydroponics for 15 days with Cd or Pb: In line with the literature, in all cultivars, the genotoxic damage induced by Pb was more severe compared to Cd. However, a cultivar-specific response was evidenced since Spagnolo showed, under metal stress, a significantly higher genome template stability compared to the other examined cultivars. The lower genotoxicity observed in Spagnolo could depend on the lower intracellular metal concentration measured in this cultivar by chemical analysis. Accordingly, light microscopy highlighted that Spagnolo developed smaller and more numerous epidermal cells under metal stress; these cells would provide a larger wall surface offering a wider metal sequestration compartment in the apoplast. Full article