Heavy Metals In Different Parts Research Articles

Heavy metals removal from industrial wastewater of Biskra (Algeria) by Arundo donax and Phragmites australis.

Industrial effluents pose a serious environmental problem, because they contain toxic contaminants mainly heavy metals that are the most dangerous to humans, animals, plants, and the environment in general. Phytoremediation using macrophytes is an adopted technique for the environment decontamination due to its efficiency and cost-effectiveness. The present study aims to highlight the capabilities of macrophytes to remove heavy metals from wastewater of Biskra region (Algeria). The methodology consists of filling out the filters planted with Arundo donax and Phragmites australis with raw industrial wastewater, then recovering decontaminated water after 15 days to assess removal of lead, copper, zinc, and iron. Both plants had shown a good efficiency for the removal of metals loaded in wastewater eliminating about 94 to 98% of initial concentration. In addition, calculated bioaccumulation factor (BAF) had confirmed the accumulation of heavy metals in different parts of experimental plants; recorded values of BAF > 1 allowed the consideration of Arundo donax and Phragmites australis as good hyper-accumulator plants. Obtained results confirm the efficiency of phytoremediation technology using macrophytes for the wastewater treatment in particular and the environment decontamination in general.

Assessing the deposition of heavy metals in edaphotopes and synantrophy vegetation under the conditions of technological pollution of the city

The object of this study is a regional center with a developed industry and a significant traffic load. The study provides an assessment of the impact of the urbanization process on the conditions of development of urban edaphotopes and their role in the functioning of urban ecosystems. It was determined that the geochemistry of the soils of urban ecosystems is significantly different from natural landscapes, which is due to the symbiosis of natural and anthropogenic factors. The content of mobile forms of heavy metals in the soil of 14 localities of different functional zones within the city was investigated. A comparative assessment of the spatial heterogeneity of the content of heavy metals in the vegetative organs (root, shoot) of the diagnostic species Polygonum aviculare L. was performed. Based on the sources of emission of heavy metals and the formed geochemical anomalies, a direct dependence was established on their accumulation by the vegetative organs of Polygonum aviculare L. According to the calculated biological absorption coefficient (BAC), high bioavailability for the accumulation of man-made toxicants Cu, Zn, Pb, Cd by the phytomass of Polygonum aviculare L. was proven. It was determined that the content of heavy metals in different parts of the test object is due to their physiological ability to accumulate these toxicants in the root and above ground mass. Active translocation of toxicants from the soil to the roots is characteristic of localities with intense influence of man-made factors, for which the value of the bioavailability coefficient varies within 0.6>BAC<0.85. Correlation coefficients between the content of heavy metals in the atmosphere, soil, and vegetative organs of the plant were determined. The research allows us to evaluate the prospects for using Polygonum aviculare L. as a cumulative indicator of metal pollution in urban technogenic ecosystems and their high phytoremediation value under conditions of environmental pollution with heavy metals

Mangrove (Avicennia marina) parts as proxies in marine pollution of Nizampatnam Bay, East Coast of India: An integrated approach

This study focuses on the assessment of heavy metals (HM) concentration and pollution status of the Nizampatnam Bay, east coast of India, from mangrove plant parts (roots and leaves) and sediment samples. This is the first of its kind work (comparison of data from both mangrove and sediment samples) from the third largest mangrove ecosystem in India. To carry out this work, plant (Avicennia mariana) and sediment samples were collected from five stations. The collected samples were carefully subjected to the laboratory methods and heavy metal concentrations were determined by using inductively coupled plasma-optical emission spectroscopy (ICP-OES). The obtained results were juxtaposed with the optimal values of world surface pollution rock averages, and noticed heavy metals such as Cd and Cu exceed the optimal values. To know the contamination levels and the chemical elements that contribute to the pollution, various environmental indices, viz., contamination factor, enrichment factor, geoaccumulation index, and pollution load index were, carried out on the sediment sample data. To ascertain the mangrove plant's capacity (in the study area) for accumulation and translocation of heavy metals in different parts of the plants, factors such as bio-concentration and translocation were calibrated.

Assessment about bioindicator capacity of acrocarpous moss Campylopus schmidii exposed to abandoned pyritic tailings.

Terrestrial mosses are promising species to study concerning metal deposition, absorption, and soil fertility as moss biocrusts. However, acrocarpous moss, as a kind of terrestrial mosses, has not yet been well understood, both in environmental monitoring and ecological application, especially exposed to an abandoned pyrite mining. Herein, we investigated the concentrations of different heavy metals in soil underlying acrocarpous moss Campylopus schmidii at three distances from an abandoned pyrite mine tailings (0.5, 1, 2km) by sampling analysis, as well as the accumulation properties of heavy metals in different parts of mosses and soil nutrients under intact mosses and moss-free layers. The results indicated that the soil we researched was heavily polluted by Cr, Cu, and Cd, which was 4.46, 4.18, and 1.77 times higher than the standard of risk screening values for soil environment quality in China. And there was a marked difference in the concentrations and distribution of heavy metals in mosses, with higher concentrations of Cr, Cu, Ni and Pb mainly in the ageing parts. In addition, mosses can effectively promote soil fertility. Compared with the bare soil without the moss layer, the total organic matter and total potassium concentrations of the soil covered by the intact moss layer were significantly increased, by 113.91% and 186.08% respectively. Correlation analysis indicated that similar pollution sources for Zn, Cd, Cu, and Pb, and the concentrations of these heavy metals in soil connected with the distance from the source of pollution. Overall, we expected that these findings could assess the greater potential of single native dominant moss species C.schmidii to act as biomonitors in specific pyrite mine tailings characterized by barren soil with strong acids (pH<4.0) and polymetallic pollution. Meanwhile, our results revealed may serve as a possibility reference for similar areas and is recommended for developing a vegetative cover utilizing local acrocarpous mosses to achieve greening of degraded tailings in the future, as well as environmental management and protection.

Some Heavy Metals in Different Parts of Consumed Chickens in Lahijan City – Iran; Health Risk Assessment

Some Heavy Metals in Different Parts of Consumed Chickens in Lahijan City – Iran; Health Risk Assessment

Heavy Metals in Cassava (Manihot esculenta Crantz) Harvested from Farmlands along Highways in Owerri, Nigeria

Concentrations of heavy metals (Cu, Pb, Zn, Ni, Cd) in cassava grown on farmlands along highways in Owerri, was investigated. Cassava leaves and root samples were harvested from cassava farms along three major roads with high traffic density and another rural road that served as control location. Standard laboratory procedures to determine the concentration of these metals were adopted using Atomic Absorption Spectrophotometer. The metal concentrations in mg/kg in cassava root showed high levels of Cu (6.29±0.0346), Zn (8.49±2.243), Pb (0.5267±0.3156) and Cd (0.1167±0.0833). The concentrations of the heavy metals in the cassava leaves were of the order: Zn &gt; Cu &gt;Pb&gt; Ni &gt; Cd. Soil plant transfer factor values for all the metals in all the sites indicated medium accumulation. Heavy metal concentrations in soil showed significant correlation with concentrations in cassava root with no significant statistical differences in bioaccumulation of heavy metals in different parts of cassava. The overall results showed evidence of some heavy metal pollution on the soils and cassava plant.

An assessment of toxic heavy metals in soil and plants (Allium cepa and Daucus carota) by GFAAS

ABSTRACT Toxic metals were identified from soil and different edible and non edible parts of Allium cepa and Daucus Carota. Results showed that there is significant metal movement from soil to vegetables. Different vegetables have different mechanism of metal sorption and uptake. Levels of heavy metals in soil were in the order of Zn>Cu>Ni>Sb>Co>Mn>As>Cd>Pb>Cr before the cultivation of vegetables i.e. Allium cepa and Daucus carota. Ten in number heavy metals including essential metals i.e. Zinc, Copper and Manganese and non essential metals nickel cobalt, arsenic, cadmium, antimony, chromium and lead were selected for investigation. Samples were classified into soil before cultivation, after cultivation, edible and non edible parts of vegetables Allium cepa and Daucus carota. The results showed significant metal movement in the entire chain from soil to the different parts of vegetables. These vegetables were grown in the selected soil samples and heavy metals were estimated by using graphite furnace atomic absorption spectrometer. Soil samples were also analysed again and significant reduction in metal concentration was found after vegetation. Results of heavy metals in different parts of the Allium cepa and Daucus Carota showed a very interesting correlation that toxic metal movement was automatically stopped when reached near the edible part of the vegetables. It seems as if some natural barriers across the plant persist which prohibit the toxic metal movement towards the edible parts. It is quite evident from the results that metal movement from soil to vegetables is significant and it should remain same in the edible parts as well. But in edible parts metal amount was extraordinary low which can not be considered as dangerous for human health. The results provide useful biological and toxicological effect of toxic heavy metals in soil and edible and non edible parts of vegetables.

Sub-cellular localization and quantitative estimation of heavy metals in lemongrass plants grown in multi-metal contaminated tannery sludge

Major objective of the study was to assess the localization pattern of heavy metals in different parts of lemongrass plant when grown in multi-metal contaminated sites. Microscopic and quantitative investigations (by ICP-OES) were carried out in root and leaves of plant to examine the compartmentalization of heavy metals. Along with it, the morphological variations in the size of trichomes in test plants were also perceived. Differential distribution of Cr, Pb, Ni and Cd was observed in root and leaf sections. Localization of these heavy metals in different parts of the plant cultivated in sole tannery sludge was compared with the plants grown in garden soil; which served as control. Histochemical methods for Pb, Cd and Ni detection revealed their significant accumulation in the root and leaf sections. Cr accumulation in roots of test plants was confirmed by fluorescence staining. Translocation factor <1 was recorded for Cr but greater than 1 for Ni and Pb. Moreover, Bioaccumulation factor >1 was observed for Ni and Pb. SEM studies revealed that the size of trichomes enlarged in plants grown in tannery sludge. Hence, our study provides an insight into the localization pattern of heavy metals in lemongrass plants and suggests that lemongrass can serve as a Ni and Pb phytoextractor when grown in multi- metal contaminated sites. In addition, enhancement in the size of trichomes was detected due to heavy metal stress which may prompt increment in essential oil yield thus; cultivation of lemongrass in heavy metal contaminated sites can also prove profitable economically.

Application of artificial neural network model for the identification the effect of municipal waste compost and biochar on phytoremediation of contaminated soils

This research was carried out to assessing the potential of Bromus tomentellus for phytoremediation with biochar and municipal waste compost amendments to improving the clean-up efficiency of soils contaminated with chromium (Cr) and zinc (Zn). Soil amendment was added to contaminated soil in three levels (%0: Control; without organic fertilizer, biochar and compost 1%, biochar and compost 2%). It also determines the applicability of artificial neural network (ANN) in the modeling of the extraction process. The physiochemical properties of the contaminated soil, including pH, Electrical Conductivity (ECe), Cation Exchange Capacity (CEC) and Sodium Adsorption Ratio (SAR) were determined. After validation of the applied artificial neural network, the effect of municipal waste compost and biochar treatment on the absorption of heavy metals in different parts of the plant was investigated. Also, the range of adding amending factors to the soil through the neural network increased from 2% in experimental data to 5% in predicting data. The neural network was taught for heavy metals in soil and plant, so the amount of Correlation coefficient (R2) value in most cases was higher than 0.9 and close to 1 which means the Group Method of Data Handling (GMDH) and artificial neural network was usable for over-predicting data. The results indicated that by adding compost percentage, the absorption of Zn is also increased. The highest concentration of Zn (274.82 mg/kg) and Cr (26.66 mg/kg) was observed by adding 0.8% compost and 0.52% biochar, respectively. The maximum Cr concentration for compost (25.19 mg/kg) was detected by adding 1% compost.

Comparative assessment ofusing Miscanthus × giganteus for remediation of soils contaminated by heavy metals: a case of military and mining sites.

Contamination of soil by heavy metals is among the important environmental problems due to their toxicity and negative impact to human health and the environment. An effective method for cleaning the soil from heavy metals is phytoremediation using the second-generation bioenergy species Miscanthus × giganteus. The purpose of this research is to study the benefits of M. × giganteus cultivation at the soils taken from the mining and former military sites contaminated by As, Pb, Zn, Co, Ni, Cr, Cu, V, Mn, Sr, and U as well as at the soil artificially contaminated by Zn and Pb, to evaluate the physiological parameters of the plant, to establish peculiarities of the phytoremediation process, and to characterize the behavior of the plant in relation to the nature and concentrations of the metals in the soils. Results showed that M. × giganteus was resistant to heavy metals (tolerance index ≥ 1) and that the greatest portion of metals accumulated in the root system. The morphological parameters of the plant while grown on different soils are influenced by soil type and the content of contaminants. The stress effect while growing M. × giganteus on soil artificially contaminated by Zn and Pb was evaluated by measuring the content of pigments (chlorophylls a, b, and carotenoids) in the plant's leaves. The decrease in the total content of chlorophylls, Сa + b/Сcar and transpiration rate of water along with the increase in the water absorbing capacity were observed. The accumulation of heavy metals in different parts of the plant was determined; bioaccumulation coefficient and values of translocation factor were calculated. The obtained results showed that M. × giganteus was an excluder plant for nine highly toxic elements (As, Pb, Zn, Co, Ni, Cr, Cu, V, U) and an accumulator species for the moderately dangerous elements (Mn, Sr). Further research will be focused on the extraction of stable stimulated plant-growth-promoting rhizobacteria from the rhizosphere of M. × giganteus and formulation on that base the plant-bacterial associations as well as on the comparison of the plant physiological parameters, biochemical soil activity, and accumulation of heavy metals in the Miscanthus tissues between first and second vegetations.

Accumulation and Translocation of Heavy Metals in Eggplant (&amp;lt;i&amp;gt;Solanum melongena L.&amp;lt;/i&amp;gt;) Grown in a Contaminated Soil

A pot experiment was conducted to investigate the effects of the rock phosphate application on accumulation and translocation of heavy metals from the soil to the roots, shoots and fruits of eggplant (<i>Solanum melongena</i> L.) grown in a sewage sludge amended soil contaminated with Cd, Pb and Ni were 30, 30 and 60 mgkg^-1, respectively. The obtained results demonstrated that the sewage sludge application caused a significance accumulation of metals in the fruits of eggplant. The concentrations of these metals in the fruits were in the order of: Pb > Cd > Ni. The fruits of eggplant were not safe for the human consumption, because the levels of heavy metals exceeded the permissible limits. These, heavy metals in different parts of eggplant can be ranked in the order of: roots > shoots > fruits, were (mgkg^-1). The soil-plant transfer factor (TF) showed that the order of uptake of metals by eggplant was: Cd > Ni > Pb. This calls for concern especially in the case of Pb and Cd which are highly toxic and of no known biological use. Therefore, Eggplant should not be cultivated in the farms and fields which use sewage sludge contaminated with heavy metals as an amendment.

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English

Assessment of Heavy Metals in Different Parts of Ruta chalepensis L. Rutaceae Medicinal Plant and Soil Samples Collected from Three Selected Zones in Jordan

ABSTRACTDifferent parts of Ruta chalepensis L. medicinal plant and soil samples collected from three zones in Jordan (Irbid, Al-Mafraq, and Ma'an) were analyzed for determination of Pb, Cu, Zn, Cd, Ni, and Fe by atomic absorption spectrometry (AAS). Heavy metal levels in washed and unwashed parts of R. chalepensis were evaluated and compared statistically. Results show that there was a variation in heavy metal concentrations related to washed and unwashed parts of R. chalepensis in the three zones. Moreover, Pb, Zn, Cu, Cd, and Ni were concentrated in the following order: flowers > leaves > stems, whereas Fe was concentrated in the following order: leaves > flowers > stems. Two standard reference materials of plant (SRM 1790a; spinach, CRM 281; ryegrass) and a standard reference material of soil (GBW 07406) were examined to validate the method used. Results indicate that high recoveries were obtained. Significant variation existed in metal content in different parts of R. chalepensis L. for the various locations (P ≤ 0.05).

Phytoremediation of heavy metal contaminated buriganga riverbed sediment by Indian mustard and marigold plants

Locally available Indian mustard (Brassica juncea) and Marigold (Tagetes patula) plants can be used in a cost‐effective, environment‐friendly approach for treatment of landfills developed using heavy metal contaminated Buriganga riverbed sediments. In this study heavy metal uptake by Indian mustard and Marigold plants from heavy metal contaminated Buriganga riverbed sediments were assessed. Initial characterization of the Buriganga riverbed sediments showed concentrations of chromium, lead, copper, and zinc in the sediments higher than the toxicity reference values given for these heavy metals in soil for terrestrial plants, and soil invertebrate. The average background concentration of chromium, lead, copper, and zinc in the Buriganga riverbed sediments were found to be 141.5 mg/kg, 34.9 mg/kg, 38.7 mg/kg, and 287.5 mg/kg, respectively. Hence the newly developed area using such landfills poses a great threat to the surrounding flora and fauna. It was observed that both Indian mustard and Marigold plants accumulated these heavy metals in different parts of the plant from the contaminated sediments and were able to maintain a growth rate of more than 90% compared to that in noncontaminated soil. The results indicated rapid phytoextraction of most heavy metals by the Indian mustard during its final growth phase, whereas rapid phytoextraction of most heavy metals was observed in case of Marigold in its initial growth phase. Total chromium, lead, copper, and zinc uptakes (in mg/kg of plant dry weight) by Indian mustard plant in 12 weeks were 102.6, 28.9, 53, and 1861.5, respectively. The uptakes (in mg/kg of plant dry weight) of the same heavy metals by Marigold plant in 12 weeks were found to be 112.3, 104.25, 82.5, and 716.75, respectively. Marigold showed higher uptake efficiency for chromium, lead, and copper, while Indian mustard was found to be more efficient for zinc uptake. Hence both of these plants can be appropriately used as necessary for treating heavy metal contaminated landfills developed using Buriganga riverbed sediments. © 2015 American Institute of Chemical Engineers Environ Prog, 35: 117–124, 2016

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The present investigation was aimed to study the distribution, enrichment and accumulation of heavy metals in soil and Vigna mungo (Black gram, var. Pant U-30) after irrigation with distillery wastewater. A field experiment was conducted in the experimental garden of Gurukula Kangri University, Haridwar during the year 2012 and 2013. Treatments of distillery wastewater viz. 20%, 40%, 60%, 80% and 100% was used for irrigation of V. mungo along with bore well water (control). The results revealed that distillery wastewater showed significant (P < 0.05/ P < 0.01) effect on the soil characteristics viz., EC, pH, Cl-, OC, Na+, K+, Ca2+, Mg2+, Fe2+, TKN, PO43-, SO42-, Cd, Cr, Cu, Mn and Zn of the soil. The soil characteristics were recorded to be positively correlated with different concentration of distillery wastewater. The agronomical characteristics viz., shoot length, root length, number of flowers, pods, dry weight, chlorophyll content, leaf area index (LAI), crop yield and harvest index (HI) of V. mungo were recorded maximum with 40% concentration of distillery wastewater. The biochemical components viz., crude proteins, crude fiber and crude carbohydrates were noted maximum with 40% concentration of distillery wastewater. The enrichment factor of heavy metals was in the order of Cd>Cr>Zn>Cu>Mn for soil and Cu>Mn>Zn>Cr>Cd for V. mungo after irrigation with distillery wastewater. The accumulation of various heavy metals in different parts of V. mungo were in order of leaves>shoot>root> fruits for Cu, Mn and Zn, root>shoot>leaves>fruit for Cd and Cr after distillery wastewater irrigation. Therefore, the distillery wastewater with appropriate dilution can be used as a bio-fertigant for the V. mungo.

Effect of Organic Acids on Heavy-Metal Uptake and Growth of Canola Grown in Contaminated Soil

Heavy-metal pollution of soils causes many environmental, animal, and human health problems. Phytoextraction of heavy metals from contaminated soils is an effective and economic technique. Humic acids are naturally occurring phenol body polymerisates, which form chelate compounds with heavy metals. In the present study the influence of soil- applied humic, citric, and malic acids on the lead (Pb), cadmium (Cd), and chromium (Cr) uptake from a contaminated soil by canola plant was examined in a greenhouse experiment. The experiment was arranged in factorial design based on randomized complete blocks with three replications. The factors of experiment included three organic acids (humic, citric, and malic acid) as first factor and five concentrations [0, 0.001, 0.002, 0.003, and 0.004 (v/v)] as second factor. The results showed that increase in organic acid concentration significantly increased heavy-metal uptake by canola plant, which accumulated heavy metals in different parts of the plant. In addition, crop growth representing by plant height and plant dry weight as well as seed production significantly decreased. Based on these results, canola can be considered as effective crop for phytoextraction of heavy metals from contaminated soils.

Photochemical Studies of&lt;i&gt; Eichhornia crassipes&lt;/i&gt; (Water Hyacinth)

Eichhornia crassipes is a floating macrophyte. It is capable of assimilating large quantities of toxic metals, some of which are essential for plant growth. Water Hyacinth grows rapidly in water with a high level of nutrients like nitrogen and phosphorous. The plants have been shown to absorb trace elements such as Silver (Ag), Lead (Pb), Cadmium (Cd) and Copper (Cu) reported by Lu et al [1]. The purpose of this study is to determine the distribution of heavy metals in different parts of the Water Hyacinth . Such a detail study has been taken for the first time. It is expected that the metal distribution within the plant species would be a representation of the concentration and distribution of the water in which it is found. Plants have the ability to accumulate non-essential and essential trace elements and this ability could be harnessed to remove pollutant metals from the environment. Aluminum, cadmium, calcium, copper, iron, lead, magnesium and zinc have been found in different amounts in roots, stems, leaves and flowers.

Photochemical Studies of&lt;i&gt; Eichhornia crassipes&lt;/i&gt; (Water Hyacinth)

Eichhornia crassipes is a floating macrophyte. It is capable of assimilating large quantities of toxic metals, some of which are essential for plant growth. Water Hyacinth grows rapidly in water with a high level of nutrients like nitrogen and phosphorous. The plants have been shown to absorb trace elements such as Silver (Ag), Lead (Pb), Cadmium (Cd) and Copper (Cu) reported by Lu et al [1]. The purpose of this study is to determine the distribution of heavy metals in different parts of the Water Hyacinth . Such a detail study has been taken for the first time. It is expected that the metal distribution within the plant species would be a representation of the concentration and distribution of the water in which it is found. Plants have the ability to accumulate non-essential and essential trace elements and this ability could be harnessed to remove pollutant metals from the environment. Aluminum, cadmium, calcium, copper, iron, lead, magnesium and zinc have been found in different amounts in roots, stems, leaves and flowers.

유통 환제의 유해 중금속 함량 및 위해도 평가

The objective of this study is investigation of contamination levels and assessment of health risk effects of heavy metals in herbal pills. 31 Items and 93 samples were obtained for this investigation from major herbal medicine producing areas, herbal markets and on-line supermarkets from Jan to Jun in 2010. Inductively coupled plasma mass spectrometer method was conducted for the quantitative analysis of Pb, Cd and As. In addition, the mer- cury analyzer system was conducted for that of Hg without sample digestion. The average contents of heavy metals in samples were as follows : 0.87 mg/kg for Pb, 0.08 mg/kg for Cd, 2.87 mg/kg for As and 0.16 mg/kg for Hg, respec- tively. In addition, the average contents of heavy metals in different parts of plants, including cortex, fructus, herba, radix, seed, algae and others were 0.63 mg/kg, 3.94 mg/kg, 1.42 mg/kg, 1.05 mg/kg, 0.16 mg/kg, 22.31 mg/kg and 10.17 mg/kg, respectively. After the estimations of dietary exposure, the acceptable daily intake (ADI), the average daily dose (ADD), the provisional tolerable weekly intake (PTWI) and the relative hazard of heavy metals were eval- uated. As the results, the relative hazards compared to PTWI in samples were below the recommended standard of JECFA as Pb 3.1%, Cd 0.9%, Hg 0.5%. Cancer risks through slope factor (SF) by Ministry of Environment Republic Korea and Environmental Protection Agency was 4.24 × 10 �7 for Pb and 3.38 × 10 �4 for As (assuming that the total arsenic content was equal to the inorganic arsenic). Based on our results, possible Pb-induced cancer risks in herbal pills according to parts used including cortex, fructus, herba, radix, seed, algae and others were 1.95 × 10 �7 , 1.45 × 10 �6 , 2.14 × 10 �7 , 6.27 × 10 �7 , 1.99 × 10 �8 , 3.61 × 10 �7 and 9.64 × 10 �8 , respectively. Possible As-induced cancer risks in herbal pills by parts used including cortex, fructus, herba, radix, seed, algae and others were 1.54 × 10 �5 , 7.24 × 10 �5 , 1.23 × 10 �4 , 2.02 × 10 �5 , 3.25 × 10 �6 , 2.18 × 10 �3 and 5.67 × 10 �6 respectively. Taken together, these results indicate

Non-Uniform Electrokinetic Removal of Heavy Metals from Contaminated Soil with Permeable Reactive Composite Electrodes

A hexagonal unit cell for non-uniform electrokinetic (EK) remediation was constructed and the electric field distribution of the cell was simulated using MATLAB software. The changes of soil pH and residues of heavy metals in different parts of the cell during the permeable reactive composite electrode electrokinetic (PRCE-EK) remediation were also studied. The results showed that, the changes of soil pH, the removal of heavy metals and the distribution of the non-uniform electric field in the cell were closely related to one another during the PRCE-EK remediation. Simulation of electric field distribution could help to predict the changes of soil pH of different parts of the cell, and then help to optimize the EK remediation process. The results also showed that an acidic migration band, which could prevent premature precipitation of heavy metals to a certain extent and promote EK removal of heavy metals, was formed in the whole hexagonal cell when the cathode used PRCE during the non-uniform EK remediation of cationic metallic ions, Cd2+ and Pb2+. After 480 hours of remediation, the total removal efficiency of Cd and Pb were 89.9% and 69.3%, respectively. Further prolonging remediation and constantly replacing electrodes with new ones could obtain better remediation results.