scholarly journals Soil additives immobilising heavy metals in contaminated soils

2022 ◽  
Vol 7 (1) ◽  
pp. 5-9
Author(s):  
Othmar Horak ◽  
Wolfgang Friesl-Hanl
Keyword(s):  
Heavy Metals ◽  
Ammonium Nitrate ◽  
Clay Minerals ◽  
Iron Oxides ◽  
Contaminated Soils ◽  
Plantago Lanceolata ◽  
Toxic Heavy Metals ◽  
Plant Availability ◽  
Other Substances ◽  
Soil Additives

Addition of iron oxides, lime, clay minerals and other substances can be used to decrease the plant availability of toxic heavy metals such as Pb, Zn, and Cd. Extractability and consequently plant concentrations may be reduced in some cases by more than 50%. The assessment of remediation processes is supported by biomonitoring methods in the field with Plantago lanceolata and in the greenhouse by barley test experiments, in combination with extraction by ammonium nitrate.

Organic and metallic pollutants in water treatment and natural wetlands: a review

2012 ◽  
Vol 65 (1) ◽  
pp. 76-99 ◽  
Author(s):  
K. Haarstad ◽  
H. J. Bavor ◽  
T. Mæhlum
Keyword(s):  
Heavy Metals ◽  
Aquatic Plants ◽  
Metal Uptake ◽  
High Capacity ◽  
Treatment Wetlands ◽  
The European Union ◽  
Toxic Heavy Metals ◽  
Limit Values ◽  
Fish Samples ◽  
Other Substances

A literature review shows that more than 500 compounds occur in wetlands, and also that wetlands are suitable for removing these compounds. There are, however, obvious pitfalls for treatment wetlands, the most important being the maintenance of the hydraulic capacity and the detention time. Treatment wetlands should have an adapted design to target specific compounds. Aquatic plants and soils are suitable for wastewater treatment with a high capacity of removing nutrients and other substances through uptake, sorption and microbiological degradation. The heavy metals Cd, Cu, Fe, Ni and Pb were found to exceed limit values. The studies revealed high values of phenol and SO4. No samples showed concentrations in sediments exceeding limit values, but fish samples showed concentrations of Hg exceeding the limit for fish sold in the European Union (EU). The main route of metal uptake in aquatic plants was through the roots in emergent and surface floating plants, whereas in submerged plants roots and leaves take part in removing heavy metals and nutrients. Submerged rooted plants have metal uptake potential from water as well as sediments, whereas rootless plants extracted metals rapidly only from water. Caution is needed about the use of SSF CWs (subsurface flow constructed wetlands) for the treatment of metal-contaminated industrial wastewater as metals are shifted to another environmental compartment, and stable redox conditions are required to ensure long-term efficiency. Mercury is one of the most toxic heavy metals and wetlands have been shown to be a source of methylmercury. Methyl Hg concentrations are typically approximately 15% of Hgt (total mercury). In wetlands polycyclic aromatic hydrocarbons (PAH), bisphenol A, BTEX, hydrocarbons including diesel range organics, glycol, dichlorodiphenyltrichloroethane (DDT), polychlorinated biphenyls (PCB), cyanide, benzene, chlorophenols and formaldehyde were found to exceed limit values. In sediments only PAH and PCB were found exceeding limit values. The pesticides found above limit values were atrazine, simazine, terbutylazine, metolachlor, mecoprop, endosulfan, chlorfenvinphos and diuron. There are few water quality limit values of these compounds, except for some well-known endocrine disrupters such as nonylphenol, phtalates, etc.

scholarly journals Heavy metal composition of maize and tomato grown on contaminated soils

2018 ◽  
Vol 3 (1) ◽  
pp. 414-426
Author(s):  
A.O. Adekiya ◽  
A.P. Oloruntoba ◽  
S.O. Ojeniyi ◽  
B.S. Ewulo
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Contaminated Soils ◽  
Heavy Metal Contamination ◽  
Mining Area ◽  
Atomic Absorption Spectrophotometry ◽  
Toxic Heavy Metals ◽  
Mining Site ◽  
Solanum Lycopersicum L ◽  
Sources Of Pollution

Abstract The study investigated the level of heavy metal contamination in plants {maize (Zea mays) and tomato (Solanum lycopersicum L.)} from thirty soil samples of three locations (Epe, Igun and Ijana) in the Ilesha gold mining area, Osun State, Nigeria. Total concentrations of As, Cd, Co, Cr, Cu, Ni, Pb and Zn were determined using atomic absorption spectrophotometry. Spatial variations were observed for all metals across the locations which was adduced to pH and the clay contents of the soils of each location. The results showed that heavy metals are more concentrated in the areas that are closer to the mining site and the concentrations in soil and plants (maize and tomato) decreased with increasing perpendicular distance from the mining site, indicating that the gold mine was the main sources of pollution. The mean concentrations of heavy metals in plants (tomato and maize) samples were considered to be contaminated as As, Cd and Pb respectively ranged from 0.6 - 2.04 mg kg-1, 0.8 - 5.2 mg kg-1, 0.8 - 3.04 mg kg-1 for tomato and respectively 0.60 - 2.00 mg kg-1, 1.50 - 4.60 mg kg-1 and 0.90 - 2.50 mg kg-1 for maize. These levels exceeded the maximum permissible limits set by FAO/WHO for vegetables. In conclusion, monitoring of crops for toxic heavy metals is essential for food safety in Nigeria.

Batch and column tests for the development of an immobilization technology for toxic heavy metals in contaminated soils of closed mines

1998 ◽  
Vol 37 (8) ◽  
pp. 81-88 ◽  
Author(s):  
A. Jang ◽  
Y. S. Choi ◽  
In S. Kim
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Contaminated Soils ◽  
Mine Drainage ◽  
Fine Sand ◽  
Design Parameters ◽  
Batch Adsorption ◽  
Toxic Heavy Metals ◽  
Chemical Additives ◽  
Column Tests

Laboratory tests of various chemical treatments for the immobilization of copper, nickel, and lead in soils typically found at mine facilities were evaluated. A series of batch, adsorption tests, and lab-scale continuous column tests were conducted to optimize the design parameters for the full-scale immobilization processes. The laboratory test program consisted of batch and column experiments to measure the leachability and subsequent immobilization of the single heavy metal, Cu2+, Pb2+, and Ni2+ in an artificial soil which was composed of bentonite and quartz fine sand. Batch equilibrium methods were used to test the ability of a large number of chemical additives to react with heavy metals in contaminated soil. The two best treatment chemicals (CaO and Na2S) for each soil-metal combination were selected for more detailed columns studies. The column tests were carried out in the acidic pH range. According to the results of the column leaching test, it was found that the degree of heavy metal leaching is highly dependent on pH. An adsorption test was performed under acidic conditions (pH 4) to evaluate bentonite as an additive to treat acid mine drainage (AMD).

The role of clay minerals and the effect of H+ ions on removal of heavy metal (Pb2+) from contaminated soils

2000 ◽  
Vol 37 (2) ◽  
pp. 296-307 ◽  
Author(s):  
Loretta Y Li ◽  
Raymond S Li
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Surface Charge ◽  
Clay Minerals ◽  
Contaminated Soils ◽  
Surface Charges ◽  
Buffer Solution ◽  
Soil System ◽  
Variable Charge ◽  
Acid Leach

The importance of the surface charge of clay minerals (fixed or variable) and the effect of H+ ions on the adsorption and removal of Pb2+ ions from contaminated soil are investigated using kaolinite (variable charge) and two illitic (fixed charge) soils with pH 3.9 and 9.2. The adsorption-desorption characteristics of Pb2+ ions were determined using batch equilibrium tests and acid leach tests with various acids used to leach the soils. Under the same adsorption conditions, illitic soil adsorbed much more Pb2+ ions than kaolinite. The difference is largely due to the surface charges on the clay minerals. Removal of Pb2+ ions from variable-charge minerals (e.g., kaolinite) requires much less effort than removal of Pb2+ ions from constant-charge minerals (e.g., illite). The surface charge of a clay mineral has an important effect. By increasing the number of H+ ions available in the soil system with a buffer solution such as NaOAc-HOAc, heavy metals adsorbed on the clay surface are expelled to pore water. The increase in H+ ions in the soil system also assists in dissolving any metal carbonates, thereby increasing the solubility of heavy metals in illitic soil. The more H+ ions available in the pore fluid, the more Pb2+ ions can be released from the system.Key words: clay minerals, sorption, desorption, heavy metal, hydrogen ion, electrokinetic, acid leach.

scholarly journals Coordination Properties of the Fungal Metabolite Harzianic Acid Toward Toxic Heavy Metals

Toxics ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 19
Author(s):  
Gaetano De Tommaso ◽  
Maria Michela Salvatore ◽  
Rosario Nicoletti ◽  
Marina DellaGreca ◽  
Francesco Vinale ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Contaminated Soils ◽  
Biological Activities ◽  
Chemical Properties ◽  
Antimicrobial Activities ◽  
Biological Properties ◽  
Phytopathogenic Fungi ◽  
Tetramic Acid ◽  
Toxic Heavy Metals ◽  
Beneficial Effects

Some Trichoderma strains are known for their capacity to produce harzianic acid, a metabolite belonging to the tetramic acid derivatives. Harzianic acid has interesting biological properties, such as antimicrobial activities against phytopathogenic fungi and promotion of plant growth. It also possesses remarkable chemical properties, including the chelating properties toward essential transition metals, which might be related to the biological activities. Increasing knowledge on chelating properties might be relevant for understanding the various beneficial effects of harzianic acid in the interaction between the producer fungi and plants. In this work, the coordination capacity of harzianic acid was studied to evaluate the formation and stability of complexes formed with toxic heavy metals (i.e., Cd2+, Co2+, Ni2+, and Pb2+), which might have a crucial role in the tolerance of plants growing in metal-contaminated soils and in abiotic stress.

scholarly journals Physical Separation of Contaminated Soil Using a Washing Ejector Based on Hydrodynamic Cavitation

2021 ◽  
Vol 14 (1) ◽  
pp. 252
Author(s):  
Kanghee Cho ◽  
Hyunsoo Kim ◽  
Oyunbileg Purev ◽  
Nagchoul Choi ◽  
Jaewon Lee
Keyword(s):  
Heavy Metals ◽  
Removal Efficiency ◽  
Contaminated Soil ◽  
Contaminated Soils ◽  
Fine Particles ◽  
Soil Aggregates ◽  
Hydrodynamic Cavitation ◽  
Toxic Heavy Metals ◽  
Treatment Technology ◽  
Physical Separation

A washing ejector is a pre-treatment technology used to remediate contaminated soil by separating fine particles. The washing ejector developed in this study is a device that utilizes fast liquid jets to disperse soil aggregates by cavitation flow. The cavitation phenomenon is affected by the Bernoulli principle, and the liquid pressure decreases with the increase in kinetic energy. The cavitating flow of the fluid through the Ventrui nozzle can remove surface functional groups and discrete particles. The main methodology involves the removal of small particles bound to coarse particles and the dispersion of soil aggregates. Particle collisions occur on the surface soil, such as the metal phase that is weakly bound to silicate minerals. It was observed that the dispersed soil affected the binding of toxic heavy metals and the mineralogical characteristics of the soil. The quantity of oxides, organic matter, and clay minerals affected the properties of the soil. An almost 40–60% removal efficiency of total metals (As, Zn, and Pb) was obtained from the contaminated soils. After treatment by a washing ejector, the volume of fine particles was reduced by 28–47%. When the contaminants are associated with particulates, separation using a washing ejector can be more effective. Therefore, physical separation improves the removal efficiency of heavy metals from soil aggregates.

ASSESSMENT OF HEAVY METAL CONCENTRATION IN COCONUT WATER

1970 ◽  
pp. 07-10
Author(s):  
MdDidarul Islam, Ashiqur Rahaman, Aboni Afrose
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Heavy Metal Concentration ◽  
Coconut Water ◽  
Toxic Heavy Metals ◽  
High Concentration ◽  
Toxic Heavy Metal ◽  
Low Concentration ◽  
Wet Ashing ◽  
Aas Method

This study was based on determining concentration of essential and toxic heavy metal in coconut water available at a local Hazaribagh area in Dhaka, Bangladesh. All essential minerals, if present in the drinking water at high concentration or very low concentration, it has negative actions. In this study, fifteen samples and eight heavy metals were analyzed by Atomic Absorption Spectroscopy (AAS) method which was followed by wet ashing digestion method. The concentration obtained in mg/l were in the range of 0.3 to 1.5, 7.77 to 21.2, 0 to 0.71, 0 to 0.9, 0 to 0.2, 0.9 to 17.3, 0.1 to 0.9, 0 to 0.9 and 0 to 0.7 for Fe, Ni, Cu, Cd, Cr, Zn, Pb and Se respectively. From this data it was concluded that any toxic heavy metals like Cd, Cr, Pb and Ni exceed their toxicity level and some essential nutrients were in low concentration in those samples. 

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