Health and environmental problems due to contamination are global concerns. Phytoremediation - a biological and sustainable technique - employs plant species to remove, slow down, integrate or ...decompose certain contaminants to purify soil and water. Our study consisted in contaminating specimens of aquatic macrophyte Hydrocleys nymphoides (Willd.) in the laboratory to test their effectiveness in absorbing and interacting with lead. We analyzed different histological planes of the section and characterized the morphological development of this species. We cultivated 30 plant specimens and 10 control specimens in hydroponic lead acetate solutions at two different concentrations each, 2 and 4 mg.L-1. Statistical analysis revealed that even after contact with lead, specimens grew normally, increasing the number of leaves and flowers. They also presented greater stomatal development and spongy parenchyma thickening, corroborating that this macrophyte can effectively decontaminate water bodies contaminated with lead, constituting a low-cost and ecological alternative.
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•A magnetic pine cone gel beads (MPCB) based adsorbent was successfully prepared.•Single and binary adsorption systems of Cu(II) and Cr(VI) were investigated.•High adsorption capacity ...of 69.8 mg.g−1 for Cu(II) and 132.5 mg.g−1 for Cr(VI).•Modeling of isotherms by statistical physics and competitive Langmuir model.•Adsorption mechanism of Cr(VI) and Cu(II) onto MPCB was elucidated.
Recently, the use of magnetic sorbents has gained a spread attention due to their eco-friendly characteristic, ease of separation and low cost. Herein, a novel biocomposite sorbent magnetic pine cone gel beads (MPCB) was synthetized and investigated for the single and the simultaneous removal of Cu(II) and Cr(VI) from aqueous solution. Pine cones waste materials were first magnetized with Fe3O4 nanoparticles then were encapsulated in calcium gel beads. The physicochemical properties of the prepared MPCB were characterized via scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction and Fourier transform infrared spectrometry (FTIR) analysis. The influences of pH, contact time and initial concentration of metal ions on the sorption process were examined. The adsorption mechanism was investigated; it mainly involved complexation/chelation with surface functional groups, electrostatic interaction and ion exchange. A physical model was adopted to attribute new physico-chemical interpretations of the adsorption mechanism. The kinetic results showed good correlation with pseudo second-order model and the equilibrium data were fitted well to the Langmuir isotherm model with maximum adsorption capacity of 68.64 and 212.22 mg g−1 for Cu(II) and Cr(VI) respectively. In the multi-components system, both competitive and synergistic effects were observed. An antagonism effect was exerted by Cu(II) ions on Cr(VI) sorption while Cu(II) adsorption was not affected and even slightly enhanced by the presence of Cr(V) ions. The competitive sorption behavior of metal ions was analyzed by the modified competitive Langmuir model which provides good fit for the Cu experimental data. This study proves that the MPCB hold great promise for using as effective sorbent for potentially toxic metals remediation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The distribution, pollution level, sources and health risk of Hg, As, Cd, Cu, Cr, Ni, Mn, Fe, Pb, Sb and Zn in urban street dust were investigated. X-ray diffraction analysis of dust samples shows ...that the mineralogy of airborne dusts is dominated by calcite, dolomite and quartz. The total concentration of trace elements across the sampling sites ranged from 36.8 to 234.3 mg kg−1 for Pb, 0.004–4.504 mg kg−1 for Hg, 160.9–778.3 mg kg−1 for Zn, 245–652 mg kg−1 for Mn, 39.4–117.9 mg kg−1 for Ni, 31.6–105.9 mg kg−1 for Cr, 49.8–232.5 mg kg−1 for Cu, 5.3–8.6 mg kg−1 for As, 0.31–0.85 mg kg−1 for Cd, 0.76–9.45 mg kg−1 for Sb, and 16,300–24,900 mg kg−1 for Fe. The enrichment factor results reveal the following order: Cu > Hg > Sb > Zn > Pb > Ni > Cr > As > Mn > Cd > Fe. Among the measured elements, the highest mobility factor belongs to Pb (79.2%), Hg (74.6%), Zn (64.1%) and Mn (56.4%). According to the calculated Hazard Quotient (HQ) and Hazard Index (HI), special attention should be paid to Hg, Pb, Zn, and Mn in the street dusts of Shiraz. Multivariate statistics indicate that traffic, natural soil particles and industrial activities are likely to be the main sources of heavy metals in Shiraz street dusts.
•This study assesses a comprehensive environmental risk of urban trace metal pollution.•This study evaluates mineralogy and human health risk combined with the speciation of trace metals.•Calcite, dolomite and quartz are main mineralogical components of dust.•This study points the critical contaminated metals that need to be paid special attention.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Soil remediation mitigates hazards from contaminants but could deprive soils of initial biota and enzymes. Historically contaminated acidic soil from Arnoldstein (Austria) and calcareous soil from ...Meza (Slovenia) were washed with 30 and 100 mmol kg−1 ethylenediaminetetraacetate (EDTA) to remove 78 and 60% of Pb as a main pollutant. Remediation of the Arnoldstein soil decreased urease activity and increased β-glucosidase activity, measured in a 15-week experiment. The dehydrogenase activity and microbial gene abundances were not significantly impeded compared to the original soil. Conversely, the use of a high dose of EDTA in the Meza soil, necessary for effective remediation of calcareous soils, resulted in pronouncedly decreased enzyme activities (3.2 times on average) and repressed fungal ITS and increased bacterial 16S rRNA gene abundance. Remediation shifted the microbial community composition in both soils. For revitalisation, the remediated soils were amended with compost, inocula of un-contaminated soil and (Arnoldstein soil) biochar enriched with soil extract. Amendments inconsistently affected the Arnoldstein soil: compost increased the dehydrogenase activity and altered the microbial community composition, biochar enhanced the β-glucosidase activity, and all amendments decreased the microbial abundance (1.6 times on average). In contrast, amendments efficiently revitalised the remediated Meza soil; compost and soil inoculum returned the enzyme activities back to the baseline in the original soil, increased the fungal abundance above that in the original soil and restored the microbial community composition.
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•Pb was efficiently EDTA-washed from acidic and calcareous contaminated soils.•Soil enzymes and microbial community were assessed as soil-health indicators.•Higher EDTA doses required in calcareous soil deteriorated microbial life.•Soil and compost amendments efficiently revitalised remediated calcareous soil.•Amendments to less EDTA-impeded acidic soil were inconsistent and inefficient.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The mine abandonment is generally associated with the release of potentially toxic metals into the environment, which may depend on metals speciation, soil properties and climate conditions. The goal ...of the present work was to assess the environmental impact of the abandoned Pb-Zn mine “Las Musas” (Spain) using an integrative approach. The impact on soils and surface waters was performed using: chemical parameters, quantification of potentially toxic metals (Cd, Cu, Pb and Zn), and ecotoxicological responses using lethal and sub-lethal bioassays with organisms' representative of different trophic level ((soil: Eisenia fetida (mortality and reproduction test); Latuca sativa and Lollium perenne (seedling emergence); and water: Vibrio fischeri (luminescence inhibition), Daphnia magna (immobility and reproduction test), Thamnocephalus platyurus (mortality), Pseudokirchneriella subcapitata (growth inhibition)). The results showed soils with neutral to slight alkaline pH (7.64–8.18), low electric conductivity (125–953 μS/cm) and low organic matter levels (0.20–1.85%). For most of the soil samples, Pb was the only metal which surpassed the limit proposed by the Canadian soil quality guidelines, with values ranging from 42.2 to 181.4 mg/kg. The ecotoxicological results showed that the soils with the highest levels of Pb induced a decrease on E. fetida reproduction and on L. sativa germination, indicating negative impacts on the habitat function. The analysis of the surface waters showed levels of Zn surpassing the legal limit adopted from the Water Framework Directive (37.0 to 69.0 μg/L). The ecotoxicological results highlight the importance of bioassays that evaluate the behavior of species, when assessing the risk of mining areas with non-acid soils and waters with high nutrients/organic matter concentrations and low concentrations of potentially toxic metals. The results indicated a moderate environmental risk from potentially toxic metals, at the areas analyzed around the Azuaga mine.
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•Environmental impact of an old abandoned Pb-Zn mine on soil and water was assessed.•Soils still have high Pb levels and restricted habitat function to soil organisms.•Water pollution with metals is low and mixed with other anthropogenic pollutants.•Environmental risk is limited in the area of the study.•Risk assessment of non-acid mining areas should integrate toxicological behavior responses.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The impacts of the partitioning of potentially toxic metals (PTM) within the estuarine environment is highly complex, but is of key significance owing to increases in populations living within such ...sensitive environments. Although empirical data exist for the partitioning of metals between the dissolved and particulate phases, little is known regarding the impacts of extracellular polymeric substances (EPS) upon the flocculation of particles within such a dynamic system nor the resultant influence on the distribution of metals between the particulate and dissolved phases. This prevents regulators from fully understanding the fate and risks associated with metals in estuaries. This study provides data associated with the simulation of 3 settlings typical of the turbulent mixing found in estuaries and partitioning of copper, cadmium, nickel, arsenic, lead and zinc for 3 salinities (0, 15, 30 PSU) reflecting the full salinity range from freshwater to seawater. Experiments were completed with and without the presence of EPS, using kaolin as the mineral particulate. The results showed significant differences between salinity, PTMs and turbulence for the experiments with and without EPS present. Overall, salinity was the main factor controlling the PTM partitioning to sediment, however the flocculation process did impact on the PTM distribution and with the addition of EPS the impact was more pronounced. The data highlighted the importance of taking account of EPS within any estuarine sediment process modelling, for relying on simple partitioning with corrections for salinity would likely lead to significant bias.
Variations in partitioning coefficient, Kp, for 6 potentially toxic metals (PTMs) at three catchment salinities for slack water at low tide (low turbulent shear stress, τ = 0.10 Pa). Solid bars show Kp for mineral-only sediment (biotic case); Outlined bars show Kp for sediment containing EPS (biotic case). Display omitted
•Turbulence shear stress impacts on trace element partitioning•Naturally occurring biopolymers significantly impact trace element partitioning•Biopolymer increases partition coefficients for some metals by orders of magnitude•Saline waters prone to partitioning changes for elements with biopolymer present•Rate of particulate PTM deposition likely to vary by two orders of magnitude across tidal cycles
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Mining and smelting of mineral resources causes excessive accumulation of potentially toxic metals (PTMs) in surrounding soils. Here, biochar-based sulfidated nanoscale zero-valent iron (SNZVI/BC) ...was designed via a one-step liquid phase reduction method to immobilize cadmium (Cd) and zinc (Zn) in a copolluted arable soil. A 60 d soil incubation experiment revealed that Cd and Zn immobilization efficiency by 6 % SNZVI/BC (25.2-26.2 %) was higher than those by individual SNZVI (13.9-18.0 %) or biochar (14.0-19.3 %) based on the changes in diethylene triamine pentaacetic acid (DTPA)-extractable PTM concentrations in soils, exhibiting a synergistic effect. Cd
or Zn
replaced isomorphously Fe
in amorphous ferrous sulfide, as revealed by XRD, XPS, and high-resolution TEM-EDS, forming metal sulfide precipitates and thus immobilizing PTMs. PTM immobilization was further enhanced by adsorption by biochar and oxidation products (Fe
O
and Fe
O
) of SNZVI via precipitation and surface complexation. SNZVI/BC also increased the concentration of dissolved organic carbon and soil pH, thus stimulating the abundances of beneficial bacteria, i.e., Bacilli, Clostridia, and Desulfuromonadia. These functional bacteria further facilitated microbial Fe(III) reduction, production of ammonium and available potassium, and immobilization of PTMs in soils. The predicted function of the soil microbial community was improved after supplementation with SNZVI/BC. Overall, SNZVI/BC could be a promising functional material that not only immobilized PTMs but also enhanced available nutrients in cocontaminated soils.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Washing with organic acids and dissolved organic carbon (DOC) is a promising technique for effective removal of potentially toxic metals from agricultural soils and the two key factors are the ...screening of inexpensive, high-efficiency, and environmentally friendly washing agents and the safe treatment of waste eluent. We used extracts from agro-forestry wastes (pineapple peel, lemon peel, grapefruit peel and gardening crabapple fruit) to develop a facile two-stage sequential washing method (extracts and/or citric acid (CA) and coupled with extracts) and regenerated waste eluent. The washing efficiencies of Cd and Cu were significantly increased by pineapple peel (PP) using two-stage sequential washing with the sequence of PP + CA-PP > CA-PP > PP-PP. The potential pollution risk from soil Cd was lowered by 33.0% from moderate to low risk, and soil nutrient contents increased. 80.9% of Cd and 81.3% of Cu in waste eluent were efficiently removed by the PP residues. The removal mechanisms of metals in soils and eluents by PP washing agents and residues can be attributed to acid activation, cation exchange and complexation between metal ions and carboxyl groups. Therefore, the PP extracts and residues are potentially suitable for the removal of Cd and Cu from polluted agricultural soils and washing waste eluents.
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•Pineapple peel (PP) extracts are feasible for removal of heavy metals in farmland.•Mixed agents PP + CA-PP have a synergistic effect and enhance heavy metals removal.•Two-stage sequential washing is a facile method to achieve remediation aim.•Soil fertility is maintained or enhanced after two-stage sequential washing.•PP residues can effectively regenerate the waste eluent after soil washing.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Phytoremediation involves the use of plants to remediate contaminated sites. This study evaluates the effect of phytoremediation on mineral and heavy metal concentration in agricultural soil within ...the vicinity of mechanic village Wukari using Zea mays interplanted with Striga hermonthica (SMV-MS), Zea mays alone (SMV-M), Zea mays inter-planted with Striga hermonthica alongside the application of fertilizer (SMV-MSF) and Zea mays alone alongside fertilizer application (SMV-MF). The bioconcentration of mineral and heavy metal and their translocation factors from the root to shoot of maize plants were estimated using empirical models. The result reveals that the efficiency of phytoextraction of the mineral and heavy metals were within the range: P (3.12 – 44.71 %), K (16.89 – 96.32 %), Mg (0.013 – 94.12 %), Mn (2.31 – 99.98 %), Si (20.92 – 52.07 %), Zn (2.74 – 21.65 %), Pb (10.44 – 100 %), Cd (0.75 – 42.85 %), Fe (7.42 – 98.57 %) and Al (19.14 – 98.69 %) respectively. The mean root and shoot bioconcentration factors (BCFs) of K, Mg, Mn and Al were greater than one indicating higher accumulation of the elements in the root and shoot of the maize plants. The root BCF of the elements was generally in the order: Mn > K > Mg > Cd > S i > Al > P > Fe > Zn > Pb while the shoot BCF was in the order: Mn > K > Mg > Al > Fe > Cd > S i > P > Zn > Pb. The mean root to shoot translocation factors (TF) of P, Mn, Zn, Pb, Cd, Fe and Al were greater than one indicating effective translocation of the elements from the root to shoots. The translocation factors were generally in the order: Fe > Al > Pb > Mn > Zn > P > Cd > Mg > S i > K.
Soil management using fertilizers can modify soil chemical, biochemical and biological properties, including the concentration of trace-elements as cadmium (Cd), chromium (Cd) and nickel (Ni). ...Bacterial isolates from Cd, Cr, and Ni-contaminated soil were evaluated for some characteristics for their use in bioremediation. Isolates (592) were obtained from soil samples (19) of three areas used in three maize cultivation systems: no-tillage and conventional tillage with the application of mineral fertilizers; minimum tillage with the application of sewage sludge. Four isolates were resistant to Cr3+ (3.06 mmol dm−3) and Cd2+ (2.92 mmol dm−3). One isolate was resistant to the three metals at 0.95 mmol dm−3. All isolates developed in a medium of Cd2+, Cr3+ and Ni2+ at 0.5 mmol dm−3, and removed Cd2+ (17–33%) and Cr6+ (60–70%). They were identified by sequencing of the gene 16S rRNA, as bacteria of the genera Paenibacillus, Burkholderia, Ensifer, and two Cupriavidus. One of the Cupriavidus isolate was able to remove 60% of Cr6+ from the culture medium and showed high indole acetic acid production capacity. We evaluated it in a microbe-plant system that could potentially be deployed in bioremediation by removing toxic metals from contaminated soil.
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•Bacterial isolates (592) were obtained from Cd, Cr, and Ni contaminated soil.•Several isolates showed resistance to more than 2 mmol dm−3 of Cd2+, Cr3+, and Ni2+.•One isolate was simultaneously resistant to about 1 mmol dm−3 Cd2+, Cr3+, and Ni2+.•Cupriavidus sp. removed 60% of Cr6+ from the culture medium.•Cupriavidus sp. produces IAA in the culture medium and showed potential for use in bioremediation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
