scholarly journals Immobilization of Potentially Toxic Elements in Contaminated Soils Using Thermally Treated Natural Zeolite

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3777
Author(s):  
Oana Cadar ◽  
Zamfira Dinca ◽  
Marin Senila ◽  
Anamaria Iulia Torok ◽  
Florin Todor ◽  
...  

Rehabilitation of contaminated soils is a complex and time-consuming procedure. One of the most cost-effective and easy-to-use soil remediation approaches is the use of amendments that stabilize the potential toxic elements (PTE) in soil by reducing their mobility and bioavailability. The stabilization of Cu, Pb, Zn, Cd, Co, Cr, Ni in a contaminated soil using 5% and 10% amendment with thermally treated natural zeolite was investigated using a sequential extraction procedure, contamination and environmental risk factors. The results showed that after amendment, the PTE concentration decreased in the exchangeable and reducible fractions and increased in the oxidizable and residual fractions. The highest immobilization effect, consisting in the decrease of exchangeable fractions with 69% was obtained in case of 10% zeolite amendment and 90 days of equilibration time for Pb; also, more than half of the mobile fraction was immobilized in case of Zn, Cu, and Co and about one third in case of Ni, Cr, and Cd. Generally, the immobilization effect of the 5% and 10% amendment is comparable, but a higher equilibration time enhanced the immobilization effect, especially in the case of Cd, Co, Cu, Pb, and Zn.

2019 ◽  
Vol 25 (2) ◽  
pp. 169-178 ◽  
Author(s):  
Dimitrios Alexakis ◽  
Dimitra Gamvroula ◽  
Eleni Theofili

ABSTRACT Total contents of 36 potentially toxic elements are summarized for agricultural topsoil (n = 12; soil depth = 0–20 cm), subsoil (n = 12; soil depth = 20–40 cm), and representative rock samples collected from a Mediterranean site (Megara Plain, Greece). The five-stage sequential extraction procedure for the geochemical partitioning of cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), manganese (Mn), and nickel (Ni), proposed by Tessier, was applied to topsoil and subsoil collected from the study area. Soil Cd was highly associated with exchangeable fraction, illustrating high bioavailability of this element. The order of mobility of the elements was as follows: Cd > Cu > Co > Zn > Ni > Cr > Mn. Results from sequential extraction experiments illustrated that the bioavailability of Cu, Co, and Zn is moderate, while Ni, Cr, and Mn presented low bioavailability, indicating that these elements could pose a limited threat to the quality of crops. Cadmium is the chief contamination controlling factor posing moderate potential ecological risk. The contamination sources of the examined elements are discussed.


Author(s):  
Sabry M. Shaheen ◽  
Ali El-Naggar ◽  
Jianxu Wang ◽  
Noha E.E. Hassan ◽  
Nabeel Khan Niazi ◽  
...  

2020 ◽  
Author(s):  
Pablo Higueras ◽  
Karen Arroyo ◽  
JuanAntonio Campos ◽  
Jesus Peco ◽  
JoseMaria Esbrí ◽  
...  

<p>Cinnabar mining, to obtain mercury, is still an important activity for the residents of the Sierra Gorda in Mexico, so this activity is currently source of mercury emission and possibly of other potentially toxic elements (PTE). In this work, seven study sites, located in areas with presence of exploitations of active or decommissioned mercury mines, have been studies with the aim of characterizing its occurrence and their effects on soil health.</p><p>Biogeochemical analyses have been carried out with the purpose of identifying the key factors related with nutritional and toxicological status of these soils, looking for possible relationships between mercury, PTEs and their impact on the enzymatic activity of the soil.</p><p>The values ​​obtained for total mercury ranged from 5 to 159 ppm; comparing these values with those from an uncontaminated area, we observe that all zones are above reference range (0.01 to 0.03 mg/kg) and that four of them exceed the maximum permissible limits (23 mg/kg), according to Mexican regulations. Other measured PTE elements were Pb, with a range between 18.7 to 814.1 mg/kg; Cu between 45.4 to 94.2 mg/kg; Zn between 145.1 to 555.8 mg/kg; As between 30.5 to 1590 mg/kg; and Sb between 18.3 to 169.6 mg/kg.  Comparing with other areas, anomalous concentrations of trace elements in soils with the following values are considered: Pb up to 10,000 mg/kg, Cu up to 2,000 mg/kg, Zn up to 10,000 mg/kg and As up to 2500 mg/kg; none of the determined elements exceeds these reference values. In the case of enzymatic activities, a range between 111.36 and 332.38 µgTPF g<sup>-1</sup>day<sup>-1</sup> was obtained with dehydrogenase. These values are slightly higher compared to other Hg contaminated soils (110 µgTPF g<sup>-1</sup>day<sup>-1</sup>) described by this team. For the acid phosphatase, a range between 516.72 to 1606.34 µgPNF g<sup>-1</sup>h<sup>-1</sup>; and for alkaline phosphatase a range between 1624.92 to 4070.82 µgPNF g<sup>-1</sup>h<sup>-1</sup>. These values correspond to those measured in Sokolov, Czech Republic, ranging from 381 to 1510 µgPNF g<sup>-1</sup>h<sup>-1</sup> for acid phosphatase and 455 to 4820 µgPNF g<sup>-1</sup>h<sup>-1</sup> for alkaline phosphatase measured in topsoil layer from spoil heaps after brown coal mining.</p><p>Our results show that the soil has contents of PTE elements indicating low pollution degree, except for Hg, registering concentrations above the maximum permissible limits for non-industrial soils; however, the results of the enzymatic activity reflect a "good" activity. Therefore, the incidence of the presence of these metals in the soil health, as measured through enzymatic activity, does not have a significant impact and the studied soils can be considered as suitable for commercial, residential or agricultural uses.</p>


2020 ◽  
Vol 134 ◽  
pp. 105046 ◽  
Author(s):  
Kumuduni Niroshika Palansooriya ◽  
Sabry M. Shaheen ◽  
Season S. Chen ◽  
Daniel C.W. Tsang ◽  
Yohey Hashimoto ◽  
...  

Chemosphere ◽  
2008 ◽  
Vol 73 (5) ◽  
pp. 776-784 ◽  
Author(s):  
J. Kierczak ◽  
C. Neel ◽  
U. Aleksander-Kwaterczak ◽  
E. Helios-Rybicka ◽  
H. Bril ◽  
...  

2020 ◽  
Vol 12 (22) ◽  
pp. 9370
Author(s):  
Marie Hechelski ◽  
Brice Louvel ◽  
Pierrick Dufrénoy ◽  
Alina Ghinet ◽  
Christophe Waterlot

The effects of P-fertilizers (mono- and di-calcium phosphates) on the bioavailability of metals and nutrients in leaves and stems of Miscanthus × giganteus were studied in mesocosm and field experiments in order to propose a new way for the valorization of miscanthus biomass. The concentration of potentially toxic elements was generally higher in stems than in leaves. Although P-fertilizers were added to contaminated soils under sustainable conditions (from 0.022% to 0.026% w/w), the average of leaf and stem biomass generally increased in the presence of P-fertilizers due to the changes in the speciation of phosphorus. Leaves of the investigated miscanthus may be of great interest as a catalyst in organic chemistry, since the Ca concentration was up to 9000 mg kg−1 DW. Stems represent a potential biomass that can be used as renewable resource of Lewis acids, currently used in organic syntheses (the sum of Zn, Cu, Mn, Fe, Mg, Si and Al was near 1000 mg kg−1 DW). The percentage of Cd and Pb in leaves and stems of miscanthus did not significantly change with P-fertilizers. Depending on the mesocosm and field experiments, it ranged from 0.004% to 0.016% and from 0.009% and 0.034% for Cd in leaves and stems, respectively, and from 0.004% to 0.015% and from 0.009% and 0.033% for Pb in leaves and stems, respectively.


2021 ◽  
Author(s):  
Sabina Rossini-Oliva ◽  
Erika S. Santos ◽  
Maria Manuela Abreu

<p>In many countries is quite common that abandoned mines are close to agricultural areas and might be used for plant food cultivation or animal grazing. However, soils adjacent to mining areas and/or developed on mine wastes can be a source of potentially toxic elements (PTE) for plants. This might be a potentially risk for human and animal health needing to be monitored before taking a decision.</p><p>Ferragudo is an abandoned Fe–Mn mine located in SW of Portugal (Beja district) considered with intermediate level of environmental hazard impact due to small volumes of mine wastes with relatively low total concentrations of PTE, except for Mn. In this area holm oak woodland was implemented and soils are usually used for grassland. Animals such as cow, sheep and goat graze in this mining area. Chemical characterization of soil-plant system and potential human health risks of the plants associated with soil contamination were assessed. Samples of oak and grass (total n=8 each) were collected (spring 2017) and composite soil samples around plants, up to 10 cm depth were also collected. Soil properties were analyzed and concentrations of macro and micronutrients in soils and plants (shoots) were determined.</p><p>No statistical differences were observed between soils around grass and oak for all the studied parameters. Soils had a pH close to neutral and a good fertility. The mean total content in soils was 86.12 and 88.36 g Mn/kg, and 47.58 and 48.45 g Fe/kg around grass and oak, respectively. These values are higher than the average concentrations in non-contaminated soils of the region (0.74 g Mn/kg and 36.83 g Fe/kg). The Mn and Fe concentration in the soils available fraction (Rhizo method) was lower compared to total (397–441 mg Mn/kg and 18–11 mg Fe/kg in oak and grass, respectively). The concentration in the available fraction of other potentially toxic elements such as Cu and Zn was very low. Although the soils had high concentrations of Mn and Fe, the plant cover is significant and soils are totally colonized by herbaceous plants. Studied species showed a different accumulation pattern for the studied elements except for Cu. Quercus ilex showed concentrations of Fe in leaves (mean 158 mg/kg) lower than in grasses (mean 272 mg Fe/kg) while the opposite pattern was observed for Mn (mean 1363 mg/kg for oak and 353 mg/kg for grasses). Manganese concentrations in oak leaves were much greater than the normal range for mature leaf tissues but non-toxic for cattle and other domestic animals. The Fe concentration in the aerial part of both plants was much lower than the maximum tolerable value for cattle, sheep and poultry and also lower than the range considered normal for plants. Copper and Zn concentration in oak and grass was below the normal values for plants and lower than toxic levels for cattle. The concentration of Mn and Fe in the aerial parts of the studied plant species did not reach toxic levels for animal graze, indicating that these soils can be used for pasture.</p>


Toxics ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 184
Author(s):  
Fotis Bilias ◽  
Thomai Nikoli ◽  
Dimitrios Kalderis ◽  
Dionisios Gasparatos

Soil contamination with potentially toxic elements (PTEs) is considered one of the most severe environmental threats, while among remediation strategies, research on the application of soil amendments has received important consideration. This review highlights the effects of biochar application on soil properties and the bioavailability of potentially toxic elements describing research areas of intense current and emerging activity. Using a visual scientometric analysis, our study shows that between 2019 and 2020, research sub-fields like earthworm activities and responses, greenhouse gass emissions, and low molecular weight organic acids have gained most of the attention when biochar was investigated for soil remediation purposes. Moreover, biomasses like rice straw, sewage sludge, and sawdust were found to be the most commonly used feedstocks for biochar production. The effect of biochar on soil chemistry and different mechanisms responsible for PTEs’ immobilization with biochar, are also briefly reported. Special attention is also given to specific PTEs most commonly found at contaminated soils, including Cu, Zn, Ni, Cr, Pb, Cd, and As, and therefore are more extensively revised in this paper. This review also addresses some of the issues in developing innovative methodologies for engineered biochars, introduced alongside some suggestions which intend to form a more focused soil remediation strategy.


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